ES chapter 3 Proposed development 18 JUNE - Viridor · 2019-07-01 · opportunity to promote the...

3Ch 3Proposed development

Replacement of Lakeside EfW and HTI Facilities Lakeside EfW Ltd ES Chapter 3: Proposed development

Terence O’Rourke Ltd 227705 June 2019

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3. Proposed development

Introduction

3.1 The proposed replacement Lakeside EfW and HTI facilities encompass the following elements:

• A twin stream energy from waste (EfW) facility – located towards the centre of the application site and with a design capacity to treat 440,000 tonnes per annum (tpa) of residual waste material. The inputs will typically comprise residual municipal waste collected from households in Slough, Reading, Bracknell Forest, Wokingham, Brent, Ealing, Harrow, Hillingdon, Hounslow, Richmond upon Thames, Surrey and Wiltshire, with the remainder arising from commercial and industrial (C&I) sources from Berkshire, Surrey and West London where the waste has a similar composition to municipal waste. The EfW building will also include education, administrative and welfare facilities.

• A high temperature incinerator (HTI) – located immediately north of the EfW building and designed to treat up to 10,000 tpa. The inputs will comprise mainly clinical waste which comes from hospitals, GP surgeries and dentists, together with industrial, animal by-products and zoo wastes, contraband wastes and other public / educational wastes that require destruction as hazardous waste.

• A steam turbine generator – located to the west of the main EfW building, which is designed to utilise high pressure steam from water heated by the combustion processes and generate approximately 44 MW of electrical power, of which approximately 39 MW will be exported to the local electrical distribution network and the remainder used within the EfW and HTI. Steam created by the HTI process will be added to that of the EfW to improve the efficiency of the EfW process. The proposals will also be able to export up to 20 MWth of heat in the form of steam or hot water in the future, should an off-site recipient be identified.

• Buildings and structures ancillary to the EfW and HTI – these include: gatehouses, weighbridges, air cooled condensers, maintenance workshops, portacabins, heat stations, storage tanks, bin stores, staff and visitor parking and internal roads.

• Landscape planting – along parts of the site boundary and access road to screen the lower part of the buildings and the activity on the site at ground level.

• Drainage – a proposed surface water network for the developed site including the new access road and a proposed foul water network discharging domestic foul and trade effluent at similar flow rates to the existing EfW site into a local sewer.

• A new site access road including a footpath / cycle path – linking the proposed site directly to the existing A4 Colnbrook by-pass.

• A temporary construction compound – situated to the immediate south of the main EfW and HTI site, which will be used for the storage of materials and plant, for site offices and construction staff car parking and for any ancillary facilities required during the construction phase. This area will be fully reinstated following the completion of construction and commissioning.



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There will also be a temporary working buffer in other areas of the site to allow for ease of construction. These areas will be fully restored following cessation of use.

3.2 This chapter covers the following key elements of the proposals:

• The proposed buildings and structures

• The EfW facility / process

• The HTI facility / process

• The day to day operation of the EfW and HTI facilities

• Construction details

• Demolition of replacement facilities (should Heathrow Airport expansion not proceed)

Buildings and structures

3.3 The layout of the facilities is illustrated in figure 3.1. Three-dimensional representations of the EfW and HTI are shown in figures 3.2 a-b, please note these are computer-generated images that have not been used for assessment purposes.

The main EfW and HTI buildings and stacks

3.4 The EfW building will be 150m long, between 40 – 75m wide and up to 42m in height, relative to the ground level at the highest level of the roof (64.5m AOD). The primary axis of the EfW building will run north - south. The building is positioned towards the centre of the site and is surrounded by internal access roads and service areas. Elevations of this building are shown in figures 3.3a-b and a longitudinal section in figures 3.4a-b.

3.5 The EfW building will house the following plant process equipment: the waste reception system consisting of access ramp, waste tipping hall and storage bunker, two process lines (with each having a waste feed crane and grab, furnace feed hopper, grate, furnace (primary combustion chamber), auxiliary burners, high temperature secondary combustion zone, boiler, flue gas treatment plant and one stack and residue handling systems), a feed water treatment system, a fire water tank, a standby generator, one stack array (comprising one stack for each EfW process line and one for the HTI), control and monitoring systems and office, welfare and education centre facilities. The south facing slope of the roof will also be fitted with 1,500m2 of solar panels.

3.6 The HTI building will be 67m long, 47m wide and up to 20m in height relative to the ground level at the highest level of the roof (43m AOD). Elevations of this building are shown in figures 3.5a-b and a longitudinal section in figure 3.6. The building will be located to the immediate north of the EfW building.

3.7 The HTI building will house the following process equipment: the waste reception system (consisting of a waste storage area, a secure storage area and a bin loading zone) a conventional furnace, a high temperature secondary combustion zone, a waste heat boiler, a quench tower, flue gas treatment system linked to a dedicated stack in the EfW building, control and monitoring systems, and office and welfare facilities.



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3.8 The three 55m (77.5m AOD) stacks will be situated at the northern end of the EfW building in a stack array. The height of the stacks was determined following consultation with Heathrow Airport Limited, National Air Traffic Services and the Civil Aviation Authority. Each stack will have an outside diameter of approximately 2.25m. The stacks have been structurally designed to meet all predicted climatic conditions and will be suitably protected from lightning strike. The stacks will also have an external access ladder (with a safety hoop or safety rail) and platforms for sampling points for manual measurement and connections for continuous emissions monitoring equipment. Obstruction lights will be fitted to the top of each stack as required to meet the European Aviation Safety Agency Aerodrome Regulation and Implementing Rules (EU 139/2014).

3.9 The administration and welfare section of the EfW building will include a reception area, general office space, individual management offices and welfare facilities. The education facility will include a multi-functional meeting room (with capacity for accommodating up to 45 people and exhibition space) together with a reception / office / store room for personal protective equipment, refreshment facilities and toilets. The education centre will provide the opportunity to promote the importance of good waste management to all ages of the community.

3.10 In addition to the main control room, an electrical control room and a plant room, the HTI building will also include administration and welfare facilities, including office and store room facilities, a staff room, showers, lockers, toilets and a laundry room.

3.11 With regard to design, the EfW building will sit on a plinth of split faced blockwork in a light colour, with polished slate grey banding. Above the blockwork will be a flat metal panel cladding system in light grey. The stacks will be painted matt grey to reduce their visual impact against the sky. The roof will be clad in aluminium standing seam with a dull finish to reduce reflectivity. The main office facade will be a dark grey curtain walling system with grey infill panels at the floor zones. Louvres will be mid-grey coated steel louvres. The main tipping hall doors and ground floor roller shutter doors will be coloured mid blue and matt grey. The HTI and other buildings / structures will be constructed from the same materials and have the same appearance as the EfW building.

Steam turbine and generator

3.12 The building housing the steam turbine equipment will be 25.6m long, 24.8m wide and 17.4m in height. Elevations of this building are shown in figure 3.7 and a longitudinal section in figure 3.8. The building will be situated to the west of the EfW building and to the north of the air-cooled condensers. The pipes that connect the boilers within the EfW building to the steam turbine will form a pipe bridge that will be enclosed within cladding that matches the EfW cladding material.

Air-cooled condensers

3.13 The air-cooled condensers, which return the low-pressure steam from the turbine to water, will be situated to the immediate south of the turbine building.



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The condensers will cover a total area of 1,065m2. The condenser units will be situated on an elevated platform, see elevations in figure 3.9.

Heat stations

3.14 Two heat station buildings that will in the future enclose plant that transfers heat generated by the combustion process off site to heat users, will be situated to the west of the main EfW and HTI buildings. Heat station 1 will be 14m long, 13m wide and 9.5m high and heat station 2 will be 15m long, 10m wide and 8m high. The replacement EfW and HTI site layout has been designed to enable the combined heat and power (CHP) pipework to be installed relatively easily beneath site roads once customers are identified.

Gatehouses and weighbridges

3.15 There will be two single storey gatehouses, one at the south west entrance to the site primarily serving the EfW and HTI and the other at the south east entrance to the site, primarily serving as the staff and visitor entrance, but also for HGVs exiting the HTI. The location of both are shown on figure 3.1. The EfW and HTI gatehouse will be 10m long, 5m wide and 3m high. Staff will control access to the main EfW and HTI buildings and the weighbridges from this gatehouse. All vehicles carrying EfW waste, residues or process materials will be required to weigh in and out of the facility. The other gatehouse will be 5.5m long, 3m wide and 3m high.

3.16 The EfW facility will have two weighbridges, one for incoming vehicles and one for exiting vehicles. The weighbridges will be situated to the immediate north of the EfW and HTI gatehouse. HTI vehicles do not require weighing as HTI waste is weighed within the HTI building itself. All HTI-related vehicles will bypass the weighbridges to enter / leave the site.

Maintenance workshops and portacabins

3.17 Maintenance workshops will be provided in a building 25.6m long, 15.25m wide and 10.5m high (to the parapet). The workshop will have a total floor area of 361m2. The building is proposed to the north of the EfW gatehouse (see figure 3.1). A full complement of tools and spares required for the operation and maintenance of the EfW and HTI facilities will be held both in the workshops and in appropriate locations around the EfW and HTI buildings.

3.18 An area for six temporary portacabins, for use during maintenance shut down periods only, will be provided to the west of the maintenance car park (see figure 3.1). Each portacabin will be 7.5m long, 3m wide and 2.6m high. The portacabins will be used by the maintenance staff for welfare facilities and offices.

3.19 Between the maintenance workshop building and the portacabins will be a maintenance storage area for the storage of related equipment and a maintenance set down and turning area.



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Ancillary development

Parking

3.20 Parking for 120 cars (including two spaces for mobility impaired users) will be provided on the site to the east of the EfW building, close to the entrance of the administration, welfare and education facilities, see figure 3.1. This parking will be for the use of employees, visitors and maintenance contractors. Two parking spaces for minibuses will be provided to cater for parties of visitors attending the site. All visits will be by prior appointment. Twenty-four secure spaces for bicycles and up to five motor cycle spaces will be provided adjacent to the EfW building for use by staff and visitors.

3.21 Of the staff and visitor parking spaces 10% will be provided with electric charging points to encourage the uptake of electric vehicles. These charging points will be located immediately adjacent to the administration, welfare and education section of the EfW building. There is the ability to increase provision should there be greater demand in the future.

3.22 Eighteen car parking spaces will also be provided for maintenance staff immediately to the east of the maintenance portacabins, to the west of the EfW building.

Electrical distribution

3.23 The replacement EfW and HTI will operate on separate electrical distribution systems for internal power distribution and export power via a single grid connection. The EfW will export power to the grid under the conditions imposed by an export agreement established with a local network operator. The specific performance requirements of the grid connection will be addressed through a formal grid connection application process.

3.24 The local network distribution operator will be responsible for connecting the EfW to the national grid. It will be responsible for obtaining any permissions or permits required to develop the necessary connection infrastructure. As such the planning application boundary does not include the grid connection route from the EfW site to the substation. However, the potential effects resulting from the construction of the connecting cablework have been considered in this ES (no effects are considered to arise during operation as the cables will be underground).

3.25 The existing Lakeside Road EfW currently connects to the Longford substation, which is approximately 630m to the south east of the existing site, off Galleymead Road. As this substation is situated in an area required for the expansion of Heathrow Airport, a new substation is likely to be provided in a similar area, near the edge of the airport’s extended boundary. For the purposes of this assessment it is assumed that initially a cable route will run from the proposed replacement EfW and HTI site along the new access road to the A4 Colnbrook by-pass, route eastwards along the A4 and connect to the existing high voltage substation at the existing Lakeside Road facilities, which already connect to the Longford substation. It is then assumed that when the new substation is constructed, new connecting cables will be laid from the A4, within existing or proposed new road / road verges, to the new substation.



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Gas

3.26 One 12m high, 5.5m diameter gas storage tank is proposed to the east of the HTI building, as natural gas is required for the HTI combustion burners. However, if a direct connection to the gas mains is possible (via the proposed new access road) then this will be the preferred gas supply and the tank will not be required.

Telecommunications and data systems

3.27 The closest existing telecommunications network is situated along the A4 Colnbrook bypass. Therefore, it will be this network from which the telecommunications supply to the EfW will be sourced. The telecommunication systems to be provided at the site will comprise telephone connections, broadband internet connections, CCTV and signal cables for the fire alarm. The telecommunications cables will route from the A4, up the proposed new access road and then be distributed throughout the site via a network of ducts between buildings.

Surface water

3.28 The proposed development will give rise to surface water run-off from the roads within the site, buildings, vehicle parking areas and other hardstanding areas. It is proposed that the surface water run-off from these areas is collected via rainwater down pipes, linear drainage channels and a number of external gullies, passed through oil interceptors and silt traps and then discharged via gravity into two below ground attenuation crate systems. Here the surface water will be attenuated, prior to discharge at greenfield run off rates, into the existing ditch to the north of the site boundary. As the level of the two crates will be lower than the existing ditch, it is proposed to pump the surface water from the attenuation crates to the ditch via a rising main. The combined discharge rate of the pumps will be restricted to the greenfield discharge rate of 5.3 l/s. There is the potential for permeable paving to be used in the car parking areas and for infiltration drainage to be used in the north west of the site, depending on the outcome of infiltration testing. Infiltration drainage will not be used in the area of the former landfill site. A Class 1 by-pass separator is also proposed to minimise the pollution generated from vehicles accessing the site and the car parking area.

3.29 At present there are several ditches within and around the proposed site which require diversion as part of the replacement facilities. It is proposed to create a new ditch, running to the north of the site, to replace those that will be severed by the replacement EfW and HTI. This new ditch will match the profile of the existing and provide continuity of drainage for the adjacent land, as well as an additional discharge location for the site drainage. The surface water drainage from the site will be split into two systems and will have two discharge points to dissipate the surface water along the length of the ditch. These two systems will be based on similar catchment areas and flows as the existing pre-developed site. Smaller land drainage ditches will also be created along the south and eastern boundaries to collect land drainage and convey it to the existing drainage ditches for eventual discharge to the Horton Brook, as per the existing pre-development site.



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3.30 Surface water from the access road from the A4 will be collected using a mixture of kerbed drainage, gullies, carrier pipes and drainage ditches where appropriate. The surface water will be split, with some flowing north into the EfW site surface water drainage network via the proposed petrol interceptor and the remainder flowing south, discharging into the Colne Brook. Drainage from the A4 junction, assumed to be adopted by the local highway authority, will flow into the existing highway drainage network.

3.31 A rainwater harvesting tank will also be installed to collect rainwater from building roof areas. This water will be used on site to support site activities / processes where appropriate.

3.32 A detailed description of the drainage arrangements for the site and flood risk is included within the Drainage Strategy Report and the Flood Risk Assessment that are submitted as part of the application.

Foul water

3.33 Under normal operations there will not be any liquid process emissions from the EfW or HTI plants. Where practicable, waste waters generated from the processes will be re-used / recycled within the facilities. Process effluents and wash down waters collected from internal process areas will be collected in a process effluent system. The process effluents will then be collected within the process water drainage systems for re-use. In the event that excess process effluents are generated, such as during periods of maintenance, these will be discharged to sewer in accordance with a trade effluent consent which will be secured from Thames Water.

3.34 Subject to formal approval from Thames Water, it is proposed to discharge all foul water from the proposed development, which will principally be from domestic sources, into Thames Water’s manhole located in close proximity to the existing sludge dewatering centre to the east of the site. The below ground foul water drainage system will be separated into domestic systems and trade effluent. This is to ensure that any liquid waste produced by the industrial processes during atypical operations has been separated from the domestic system to enable a sampling point for the trade effluent waste to comply with any requirements for trade effluent licences that may be imposed by Thames Water. Domestic foul and trade effluent flows will be combined after passing through the sampling chamber prior to connection with Thames Water’s sewer.

Potable / mains water

3.35 The closest existing mains water supply is located beneath the A4 Colnbrook bypass. The replacement EfW and HTI facilities will require a new connection via the new access road. The incoming water supply will need to be separated into industrial water, fire-fighting water and potable water. Industrial and fire-fighting water supplies will be boosted on site to ensure adequate pressure is maintained in the systems.

Access and circulation

3.36 All vehicles will access the replacement EfW and HTI facilities from the A4 Colnbrook bypass. A new access road will be constructed from the bypass to



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the replacement EfW and HTI site and will require a new priority T junction, which will be situated approximately 650m to the west of Lakeside Road. The local highway network, new junction and access road are shown in figures 3.10 – 3.11. The access road will be approximately 820m long, 10.3m wide and will comprise a 7.3m wide carriageway and a 3m wide shared footway/cycleway. It will cross an existing public right of way (bridleway 2a) that connects Colnbrook to Richings Park.

3.37 The access road has been designed to accommodate two-way HGV and RCV flow and will provide two points of access to the replacement facilities. It also includes an access stub for provision of future access to adjacent land.

3.38 Figure 3.12 illustrates the various vehicle circulation routes within the site.

Security

3.39 A boundary fence for the replacement EfW and HTI facilities will provide perimeter security. This will be a 2.4m palisade fence and will extend without interruption around the outer perimeter of the EfW and HTI development area to prevent unauthorised access to the facilities. The main entrance gates will be electrically driven sliding gates. They will be open during normal working hours and closed at all other times. Pedestrian gates will be situated adjacent to the main entrance gates. They will be fitted with automatic closing mechanisms and remain closed at all times when not in use for access. Supervised CCTV will monitor the entrance gates, pedestrian gates and the whole boundary.

Lighting

3.40 The replacement EfW and HTI’s lighting design is based on the use of appropriate lighting to provide safe working conditions in all areas of the development area, whilst minimising light pollution and the visual impact on the local environment. A mixture of wall mounted and column mounted luminaires will provide lighting to walkways, roads and car parking areas. The access road from the A4 to the site entrance will be illuminated via further column mounted luminaires. The luminaires used will not project light above the horizontal plane, ensuring that direct upward light pollution will be zero and will be glare rated to minimise the impact on both human and ecological receptors. Further details are set out within the lighting assessment that accompanies the planning application.

Landscape planting

3.41 The proposal will see the site levelled to 22.5m AOD (it currently ranges from approximately 21m AOD in the north to approximately 26m AOD in the south) and the loss of the majority of the existing trees and areas of scrub vegetation within the site area. It is proposed to fence off any mature trees within the proposed temporary construction compound during site preparation and construction activities in accordance with BS 5837: 2012.

3.42 Planting within the site will be restricted to the car park area in the south east corner, with tree planting consisting of oak and alder where space is available along the northern boundary of the car park. Planting around the north and western site boundaries will include new native planting such as willow, hazel,



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field maple, spindle, alder, dogwood, holly and blackthorn. Fruit bearing trees will be kept to a minimum due to the proximity of Heathrow Airport. While not screening the EfW and HTI buildings, the planting will assist in breaking up the building mass and a degree of the ground level activity. Grass verges will be provided on either side of the proposed new access road from the new junction with the A4. The detailed landscape planting scheme for the site is illustrated in figure 3.13.

Climate change adaptation and greenhouse gas emissions

3.43 The replacement EfW and HTI facilities include the following measures to reduce their greenhouse gas emissions and minimise their vulnerability to climate change:

• The facilities will generate energy through the combustion of waste and effectively represent a low carbon energy source. The generation of low carbon energy can assist in the reduction of greenhouse gas emissions by displacing more carbon-intensive energy sources such as coal and natural gas.

• The existing EfW facility generates 40.5 MW of electricity, 37 MW of which is exported to the local grid. As well as ensuring that this low carbon energy generation will continue, the improvements in efficiency mean that the relocated EfW will increase electricity generation to approximately 44 MW and the export of electricity to 39 MW.

• The facilities will have the capability to export heat, in the form of steam or hot water, should a suitable off-site user be identified in future.

• The south-facing roof of the EfW building will be fitted with 1,500m2 of photovoltaic panels which will make a further contribution to renewable energy generation at the site.

• The facilities will use LED lighting, which will reduce electricity use.

• The low-pressure steam generated by the existing HTI facility is used to improve the efficiency of the EfW process. This arrangement will continue at the relocated facility.

• Rainwater will be harvested from the roof area to supply site activities / processes where appropriate. In addition, water-efficient fittings will be specified for the staff facilities.

• Bottom ash from the existing EfW is currently used to make aggregates suitable for construction and road projects, while the air pollution control residues (APCr) are recycled into carbon negative aggregate that is used to make carbon negative building blocks. The company that recovers the APCr is able to capture 1,056 tonnes of carbon per annum during the APCr recovery process. These arrangements will continue for the replacement EfW, resulting in reduced use of primary resources for aggregate production. It is also proposed that the carbon negative blocks will be used where possible in the construction of the replacement EfW facility, which will reduce the use of primary resources in the development.

• The application site is in flood zone 1 and is largely at low or very low risk of surface water flooding, although part of the north east of the site and the field drain on site are at medium to high risk. The surface water drainage strategy incorporates a 40% allowance for climate change and two below



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ground attenuation crates that will store surface water prior to discharging it into existing and new ditches to the north of the site at greenfield run off rates. These measures will ensure that the proposed development will not be at increased risk of flooding as a result of climate change.

• The facilities will be built in accordance with the requirements of the prevailing Building Regulations in relation to target emission rates of CO2 and target fabric energy efficiency rates.

The EfW facility

3.44 The main inputs and outputs for the EfW facility are shown in figure 3.14 and a generic flow diagram of the energy recovery process is provided in figure 3.15.

The EfW combustion process

3.45 Incoming waste will be delivered to the plant in RCVs or HGVs. The RCVs are from local residual waste collection (kerbside) rounds and the HGVs are from off-site waste transfer stations or approved third party suppliers. The plant will not operate under an open-door basis. Only approved suppliers will use the plant to ensure compliance with waste acceptance criteria as well as limits on daily inputs.

3.46 Vehicles will be weighed on arrival at the site and periodically inspected at the gatehouse before proceeding to the tipping hall. Once the waste has been tipped into the EfW bunker, the delivery vehicles will exit the EfW facility via the weighbridge and have their weight recorded again prior to leaving the site.

3.47 The waste bunker will be housed within the tipping hall and constructed in concrete. The storage capacity of the bunker will be equivalent to approximately four days of waste storage.

3.48 A crane grab will transfer the waste from the bunker into a feed hopper to feed the combustion chamber. The grab will also be used to mix and homogenise the incoming waste, and will remove any unsuitable or non-combustible items identified within the bunker. The combustion chamber will use a moving grate to agitate the fuel bed and promote good burnout of the waste, ensuring a uniform heat release.

3.49 Primary combustion air will be drawn from the waste reception areas and fed into the combustion chamber beneath the grate. This will maintain negative pressure in waste reception areas.

3.50 Secondary combustion air will be injected into the flame body above the grate to facilitate the combustion of waste on the grate. Further up the flue, above the combustion zone, ammonia will be injected to react with oxides of nitrogen formed in the combustion process. The ammonia will reduce the concentration of nitrogen oxides (NOx) in the flue gas to achieve required emission limits.

3.51 The combustion chamber will be provided with auxiliary burners. These are used during start up to ensure the combustion chamber temperature reaches the required 850°C prior to feeding of waste into the combustion chamber. Interlocks will prevent the charging of waste until the temperature within the combustion chamber has reached 850°C. During normal operation the burners



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are not used unless the temperature falls below 850°C The auxiliary burners will typically operate for up to 16 hours during a start-up event and up to two hours during a shutdown.

3.52 Bottom ash will fall from the end of the grate into a discharger, comprising a water bath. The water will act as an ash quench and make it possible to remove cooled bottom ash without dust generation. The ash will then be transferred to a dedicated incinerator bottom ash (IBA) storage area.

3.53 The EfW facility will be designed to comply with the requirements set out in the Industrial Emissions Directive (IED) and the emission limits set out in the Final Draft Waste Incineration BREF (best available technique reference document).

Energy recovery

3.54 Heat will be recovered from the flue gases by means of a water tube boiler integral with the furnace. The heat will be transferred through a series of heat exchangers. The hot gases from the furnace first pass through evaporators that raise the steam which then passes into the boiler.

3.55 Superheated steam will be supplied to a high efficiency turbine which, through a connecting shaft, will turn a generator to produce electricity. To generate the pressure drop in order to drive the turbine, the steam will be condensed back to water. The majority will be condensed in the air-cooled condenser (ACC) following the turbine at a pressure well below atmospheric.

3.56 Up to 20 MWth of heat from the EfW facility will be available for export to existing and potential local heat users. Depending on the requirements of any heat users, either high pressure steam or hot water could be supplied. High pressure steam could be extracted from the turbine and piped directly to heat users. Alternatively, low pressure steam exiting the turbine (prior to the condensers) could pass through an onsite heat exchanger to heat up water for use in a heat network. The volume of steam extracted would vary depending on the heat load requirements of the heat users.

Flue gas treatment

3.57 Flue gases generated from the combustion process will be cleaned before being released into the atmosphere to the appropriate standards required to protect human health and the environment. The flue gas treatment (FGT) systems will be designed to comply with the requirements of the Waste Incineration BAT reference document.

3.58 The abatement of oxides of nitrogen (NOx) will be achieved by careful control of combustion air and a NOx abatement system. NOx will be formed in the boiler at high temperature from nitrogen in the waste and in the combustion air. The NOx abatement system will use a NOx reagent (ammonia) which will be injected into the flue gas stream to minimise emissions of nitrogen dioxide (NO2).

3.59 The acid gas abatement system will use lime as a reagent to reduce concentrations of acid gases, such as sulphur oxides (SOx) and hydrogen chloride (HCl), in the flue gas stream.



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3.60 Powdered activated carbon (PAC) will be used as an adsorbent to remove volatile metals, dioxins and furans. Both PAC and lime will be held in dedicated storage silos and injected into the flue gas stream. The flue gases containing the reagents will pass through a reaction chamber and into a bag filter arrangement where reaction products and un-reacted solids will be removed from the flue gases. The residue, referred to as APCr, will accumulate on the outside of the filter bags. The filter bags will be periodically cleaned by a reverse jet of air displacing the filtered residue into chutes beneath.

3.61 The APCr collected by the bag filters will be held in a silo from where it will be recycled back into the flue gas stream at the top of the reaction chamber. As fresh reagents are added, an equivalent quantity of residues collected from the bag filters will be removed.

3.62 The cleaned gas will be monitored for pollutants and discharged to atmosphere via two 55m stacks (one per EfW waste treatment line).

Residues and ashes

3.63 The process will result in two separate ash streams: IBA and APCr. IBA is a recyclable non-hazardous waste. IBA from the existing EfW at Lakeside Road is currently transported to a company in Brentford where it is used to make sustainable aggregates suitable for construction projects and road construction. 100% of the bottom ash from the proposed replacement facility will be used for secondary aggregate production.

3.64 APCr is classed as hazardous due to its elevated pH and requires either treatment or specialist landfill disposal. The APCr from the existing Lakeside Road EfW facility is sent for treatment and used to create a lightweight, high quality, sustainable carbon-negative aggregate called Carbon8 Aggregate which is used to make carbon negative building blocks as well as in other construction material products. These arrangements to treat and not landfill will continue for the replacement facility.

3.65 The APCr will be removed from site in enclosed tankers thereby minimising the chance of spillage and dust emissions.

Emissions monitoring

3.66 Emissions from the stack will be continuously monitored using a continuous emission monitoring system (CEMS) for the following pollutants:

• Particulates

• Sulphur dioxide

• Hydrogen chloride

• Carbon monoxide

• Nitrogen oxides

• Ammonia

• VOCs, expressed as total organic carbon



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3.67 There will be two CEMS systems, one per waste incineration line, and an installed back-up which can operate on both lines in the event of a CEMS failure. In addition, periodic monitoring will be undertaken of pollutants which are not able to be monitored continuously, such as hydrogen fluoride, metals and dioxins and furans.

Raw material handling and storage

3.68 In addition to the residual waste that will be tipped into the EfW bunker, the following raw materials will be required for EfW process operations:

• Dry lime - used to react with acid gases in the FGT process, will be stored in silos on site.

• PAC - used for the absorption of volatile heavy metals and organic components and will be added with the lime in the FGT process. The PAC will be stored in silos and delivered via tanker.

• Ammonia - used for the abatement of NOx in a NOx abatement system. Ammonia will be delivered in liquid form and stored in tanks on-site.

• Water treatment chemicals - used to treat water in the water treatment plant that provides feedwater to the boiler. The chemicals will be stored in a bunded area within the water treatment plant.

• Fuel oil - used for the primary and auxiliary support burners, the emergency generator and mobile plant and equipment. The fuel oil will be stored in a bunded storage tank.

3.69 In addition to the raw materials described above, various maintenance materials will be stored in an appropriate manner and used in small quantities. These will include hydraulic and silicone-based oils, greases, insulants, refrigerant gases for the air conditioning plant, glycol/antifreeze for cooling, welding gases, CO2 and foam agents for fire-fighting, electrical switchgear and gas emptying and filling equipment.

The HTI facility

3.70 The main inputs and outputs for the HTI facility are shown in figure 3.16 and a generic flow diagram of the HTI process is provided in figure 3.17.

The HTI combustion process

3.71 Waste will be delivered to site via road in bins. Once the delivery vehicles have unloaded, they will exit the HTI facility. The waste will then be stored within the bins in designated storage areas until such time as it can be incinerated.

3.72 The bins will be manually moved to a lift and tip unit, where the waste will be tipped directly from the bins onto the waste feed belt to a hopper. Prior to entering the lift and tip unit, the bins will be weighed on a platform scale. There will be multiple bin tippers. Automatic control systems will signal when the waste is to be tipped onto the conveyor, with an interlock preventing waste from being loaded into the hopper until conditions in the primary chamber are correct. Waste will then be fed into the primary combustion chamber via a grate system. The empty bins will be washed, disinfected and moved to a clean storage area ready for collection and reuse.



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3.73 Primary combustion air will be drawn from the waste reception areas and fed into the combustion chamber beneath the grate. This will maintain negative pressure in waste reception areas. Secondary combustion air will be injected into the flame body above the grate to facilitate the combustion of waste on the grate.

3.74 The combustion chamber will be provided with low-NOx design auxiliary burners which will combust natural gas. The burners will raise the primary combustion chamber temperature to the required 1,000-1,100°C prior to the feeding of waste into the combustion chamber. Interlocks will prevent the charging of waste until the temperature within the combustion chamber has reached 1,000-1,100°C. During normal operation, if the temperature falls below 1,000-1,100°C, the burners will be initiated to maintain the temperature above this minimum.

3.75 The secondary combustion chamber must maintain a minimum of 1,100°C. Within the combustion chamber, ammonia will be injected to react with oxides of nitrogen formed in the combustion process.

3.76 Bottom ash will fall from the end of the grate into a fully sealed system to prevent dust emissions.

3.77 The HTI Facility will be designed to comply with the requirements set out in the IED and the emission limits set out in the Final Draft Waste Incineration BREF.

Energy recovery

3.78 Heat will be recovered from the flue gases by means of a waste heat recovery boiler where the heat in the gases will be used to produce saturated steam. Gas conditioning will be used – water will be injected by twin fluid nozzles to produce the steam. The flue gases will be cooled from 1,100 °C to approximately 250-260°C. The hot flue gases will then be cooled to the correct temperature required for the abatement reactions using lime and activated carbon.

3.79 Provision will be made for heat to be exported to the EfW plant when it is in operation, to increase energy efficiency.

Flue gas treatment (FGT)

3.80 Flue gases generated from the combustion process will be cleaned before being released into the atmosphere to the appropriate standards required to protect human health and the environment. The FGT system will be designed to comply with the requirements of the Waste Incineration BAT Reference document.

3.81 The acid gas abatement system will utilise a dry system, using lime as a reagent to reduce concentrations of acid gases, such as SOx and HCl, in the flue gas stream. This abatement technology has the benefit that it does not produce a liquid effluent and does not require additional heat in the boiler flue gas to evaporate water as in a semi-dry FGT process. The lime will then be transported pneumatically to be injected into the flue gas stream. Powdered activated carbon (PAC) will be used as an adsorbent to remove volatile metals, dioxins and furans.



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3.82 The flue gases containing the reagents will pass through a reaction chamber and into a bag filter arrangement where reaction products and un-reacted solids will be removed from the flue gases. The APCr will accumulate on the outside of the filter bags. The filter bags will be periodically cleaned by a reverse jet of compressed air displacing the filtered residue into chutes beneath.

3.83 The APCr collected by the bag filters will be held in special bags from where it will be recycled back into the flue gas stream at the top of the reaction chamber. As fresh reagents are added, an equivalent quantity of residues collected from the bag filters will be removed.

3.84 The cleaned gas will be monitored for pollutants and discharged to atmosphere via a stack located within the EfW facility.

Residues and ashes

3.85 The process will result in two separate ash streams: IBA and APCr. The composition of the IBA and APCr from the HTI is different to that from the EfW and will require disposal to landfill. The APCr is also stored in bags rather than silos due to the lower volumes produced and these bags cannot currently be handled at the same facility as the EfW APCr is processed. IBA and APCr from the existing HTI plant is taken to Wingmoor Landfill at Bishops Cleeve and this will continue for the replacement facility.

Emissions monitoring

3.86 Emissions from the stack will be continuously monitored using a CEMS for the same pollutants as the EfW emissions noted previously (i.e. particulates, sulphur dioxide, hydrogen chloride, carbon monoxide, nitrogen oxides, ammonia and VOCs expressed as total organic carbon). Flow rate and oxygen content will also be measured. There will be an installed back-up CEMS which can operate in the event of a CEMS failure. In addition, periodic monitoring will be undertaken of pollutants which are not able to be monitored continuously, such as hydrogen fluoride, metals and dioxins and furans.

Raw material handling and storage

3.87 In addition to the HTI waste itself, the following raw materials will be required for the HTI process operations:

• Dry lime - used to react with acid gases in the FGT process, will be stored in silos on site. Delivery of lime will be via tanker, with pneumatic offloading by means of an on-board truck compressor into the silo.

• PAC - used for the absorption of volatile heavy metals, volatile organic compounds and dioxins and will be added with the lime in the FGT process. The PAC will be delivered by road and stored in bags/sacks in a designated storage area or in a suitably designed silo.

• Ammonia (either liquid or solid) - used for the abatement of oxides of nitrogen. The ammonia will be delivered by road and stored in big bags/sacks in a designated storage area or in a suitably designed silo/tank.



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• Water treatment chemicals - used to treat water in the water treatment plant that provides feedwater to the boiler. The chemicals will be stored in a bunded area near the water treatment plant.

• Natural gas - used by the combustion burners. The gas will be stored in a gas storage tank or supplied via mains connection.

3.88 In addition to the raw materials described above, various maintenance materials will be stored in an appropriate manner and used in small quantities. These will include the same as set out previously for the EfW (e.g. hydraulic and silicone-based oils, greases, insulants, etc.).

EfW and HTI operations

Operating hours

3.89 The EfW and HTI will both operate 24 hours a day, seven days a week, though there will be periods of annual maintenance when waste processing is reduced. These working hours are the same as at the current facilities. The majority of deliveries and collections will be received / made between 05:00 and 22:00 hours Mondays to Fridays and 06:00 and 14:00 hours on Saturdays. However, some deliveries and / or collections will take place outside of these hours to take account of traffic conditions, to prevent the build-up of waste at transfer stations and following holiday periods or for other operational reasons.

Staff

3.90 A total of 77 staff will be employed directly on site (as for the existing Lakeside Road facilities) 50 at the EfW and 27 at the HTI. The EfW will have a five-shift pattern but will use six teams, which means one team is always available for other duties and to provide cover (e.g. for holiday, sickness and training). The EfW shift pattern will be based on an average 40-hour week, working 12-hour shifts. Working hours, shift patterns and rotas will be set to meet the needs of the plant and will be regularly reviewed with the members of each team in order to ensure optimum working conditions are maintained. The 24 members of staff not working shifts or to a rota will work standard office hours.

3.91 The HTI will have a five-shift pattern and use five teams that work a 40-hour week, over 12-hour shifts. Twenty-three members of staff will work shifts. As administration work for the HTI is undertaken elsewhere, only four members of staff will work standard office hours.

Vehicle movements and trip distribution

3.92 The number of vehicle movements generated by the proposed replacement facilities will be very similar to those generated by the existing Lakeside Road facilities and will be based on operational requirements (i.e. deliveries of different waste types, deliveries of process materials, materials removed from site for processing / recycling and reject loads). Currently the EfW facility generates around 144 RCV (with a 6 tonne payload) or HGV (with a 25 tonne payload) movements each way per weekday (i.e. 288 RCV or HGV movements in total). The HTI facility generates 13 HGV movements each way per day (i.e. 26 HGV movements in total).



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3.93 The trips associated with movement of waste to the site will follow a daily distribution similar to that currently experienced by the operational facilities at Lakeside Road, with a peak in late morning and early afternoon, with minimal trips to site during the traditional peak hours on the main highway.

3.94 In addition to the delivery of wastes and process materials and the export of process materials, vehicle movements will also be generated as a result of maintenance activities, deliveries related to administration and welfare on site, and visitor and staff movements. In relation to maintenance, administration and welfare activities, it is anticipated that these will be limited.

3.95 The EfW will employ a total of 50 staff, mostly in a shift pattern. At any given time approximately 25 - 30 personnel will be present on site during the day, three of these will be in administration roles (working from 08:00 to 17:00) and approximately three personnel will be present overnight and at weekends. The site will operate 24 hours per day, with the shift changeover taking place outside of the peak traffic flow hours on the public highway. Overall staff traffic generation will be minimal.

3.96 Similarly, the HTI will employ a total of 27 staff, mostly in a shift pattern. Approximately 5 - 10 personnel will be present on site at any given time. HTI operations will also take place 24 hours per day, with the shift changeover outside of the peak traffic flow hours on the public highway.

3.97 Due to the nature of the facilities it is anticipated that most of the visitor trips will be made outside the conventional peak hours and amount to a few each month.

3.98 The majority of waste deliveries to the EfW and HTI facilities will be made in RCVs, HGVs and smaller vehicles (box vans) and these will continue to use the A4 Colnbrook by-pass and wider road network to access the site just as existing deliveries to the Lakeside Road facilities do.

Education facilities

3.99 The EfW and HTI replacement site will be available for visits by local interested parties during the normal day shift opening hours, by prior arrangement, subject to health and safety and operational priorities. Grundon Waste Management and Viridor have a history of supporting education and research projects and specific provision will be made for the presentation of the facilities and operations as a resource for local schools and educational establishments.

Maintenance

3.100 The EfW and HTI facilities will operate a detailed maintenance programme to ensure systems and equipment operate safely, effectively and reliably. The maintenance programmes for the two facilities will aim to maintain and improve overall efficiency, reduce emergency repairs, reduce unscheduled equipment shutdowns and the duration of such shutdowns, decrease process faults or reduced performance due to equipment problems and extend the useful life of equipment, repairing and adapting it where necessary.



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3.101 Individual items of plant and equipment (e.g. nozzles, filters, electric motors etc.) will have a defined frequency of inspection, checking, cleaning, adjustment and servicing. Maintenance of large items of equipment at the EfW facility (e.g. the boiler, flue gas treatment equipment, grate, hopper and ash handling) will require each line to be shut down. It is estimated that each EfW line will need to be shut down for approximately 17 days per year. Depending on the results of these shutdowns, a total shutdown of both lines simultaneously for approximately 14 days is likely once every four years, during which maintenance of the shared items of equipment takes place (e.g. steam turbine, generator). The HTI, with its one line, will need to be shut down for approximately 44 days per year over three separate periods, usually in May, August and December, with August being longer to allow for maintenance of the main plant components.

Spillages

3.102 Due to the proposed nature of operations at the site there is potential for a range of spillages involving significantly different materials. A number of spill procedures will be produced for each potential spillage event identified, including spillage of raw material inputs to the plant, ready use consumables and waste material outputs. Suitable and sufficient equipment will be maintained on site (such as spill kits) in order to deal with the predicted scale of possible spillages of material. Staff will receive training in the use of the spill kits and will regularly practise as part of the normal operation of the facility. Under all circumstances, priority will be given to the potential environmental and health and safety impacts of spillages. Engineering controls will be employed where these would reduce the potential for spillage (or minimise the impact of spillage) e.g. bunded areas for fuel storage above ground.

Abnormal operating conditions

3.103 Procedures and training will be in put in place for dealing with abnormal operating conditions (e.g. failure of an auxiliary burner, FGT bag, CEMS or electricity supply). The EfW and HTI facilities have been designed to avoid the need for regular shutdowns but if any incident endangers or is likely to endanger personnel, or there is a risk of serious damage to the facilities, or a complete power failure, an emergency shutdown will be necessary (a standby generator will be present on site to support the safe shut down of the facilities at any time). A full set of procedures will be developed and implemented on site for an emergency shutdown. These will be published in an Emergency Plan. Appropriate drill and training exercises will be undertaken at regular intervals to ensure that all plant operatives are aware of and are competent to identify and respond to plant emergencies.

3.104 The EfW and HTI facilities will be equipped with comprehensive fire protection and detection systems which will comply with the requirements of the National Fire Protection Association’s recommended practice for fire protection for electricity generating plants and high voltage direct current converter stations (NFPA 850). Automatic fire alarm detection will be provided throughout specified areas as well as manual alarm break glass call points. An underground fire main will encircle the EfW and HTI plant facilities and will supply a number of fire hydrants and will spur off at strategic points to supply the water-based fire protection system. Within the HTI a water deluge system will also be employed.



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Nuisance control

Dust and odour controls

3.105 Combustion air will be drawn from above the waste pit so that odours and airborne dust are drawn from the bunker into the incineration line thus preventing their escape to atmosphere. Odour will also be controlled by keeping the doors between the waste tipping area and the waste bunker closed when there are no waste deliveries occurring.

3.106 Waste feed hoppers will be designed to ensure that emissions of dust and odours are minimised. By ensuring that the hopper dimensions exceed those of the grab, the potential for stray items of waste to accumulate on the floor and for dust and waste to be blown from the hoppers will be minimised.

3.107 Potential emissions of dust and fumes from the bottom ash discharger will be minimised by the quenching process and storage systems proposed.

3.108 As part of ongoing occupational health protection dust level checks will be carried out on a regular basis in operational areas of the EfW facility where high dust levels may be present. This will provide an early warning of increasing dust levels, at which point action will be taken to reduce dust levels.

3.109 Daily olfactory checks will be carried out around the perimeter of the site to check for odours.

3.110 In the event of a plant shutdown, which might result in waste being held in the EfW bunker for a period of time, the doors to the bunker will be kept shut. If necessary fresh waste will be used to cap older waste in order to minimise odours. A water-based deodoriser will also be hired if necessary to assist in odour management.

3.111 Odour control in the HTI facility will be managed in a similar manner. Waste arrives at the site and is stored in secure, air-tight containers. Waste is then loaded onto the belt feeder and transferred to the furnace. The primary air for the combustion process is taken from within the HTI building, providing a level of negative pressure and minimising the emissions of odour from the facility.

3.112 There is minimal potential for dust arisings from the HTI waste pre-incineration given the nature of the waste. Dust from the bottom ash will be contained within a fully sealed system and the building will be under negative pressure.

3.113 The site access road will be properly maintained and regular checks will be carried out on road conditions. Cleaning will be carried out as necessary. Vehicles will also be checked to ensure that they are clear of loose waste and that their loads are secure.

Noise controls

3.114 Most noisy plant items will be installed inside the EfW and HTI buildings rather than outside, and equipped with noise insulation if necessary. The air-cooled condensers have been designed to reduce noise and tonal components, and have been located to the south west of the site in order to have minimum noise impact on permanent local receptors. Doors will be kept closed when not in use



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to prevent noise egress. A sound attenuator will be fitted to the exhaust of the EfW and HTI flue gas ID fans. Waste vehicle movements at night will be limited and regular maintenance of plant items will ensure noise does not become a problem.

3.115 Mobile plant for the site will comply with the most up-to-date standards, including noise emissions. All mobile plant will be operated and maintained in accordance with the manufacturer’s instructions. Mobile plant that does not comply with the agreed operating noise limits will be taken out of service until compliance is achieved.

3.116 Noise level checks will be carried out on a regular basis in operational areas of the EfW and HTI facilities where high noise levels may be present. Early warning of increasing noise levels will result in a noise reduction or mitigation programme.

Pest control

3.117 Waste delivered for disposal will only be stored in the designated areas of the two buildings and any spillage of waste will be recovered in accordance with specific, time limited procedures. This will reduce the potential for feeding patterns to be established by vermin and therefore discourages infestation. The design of the waste bunker for the EfW will ensure that the bunker is watertight and this will prevent access to the contained waste by burrowing pests such as rats or squirrels. The bunker will be enclosed and under cover thereby reducing access to waste for birds and the tipping hall have been designed so as to eliminate roosting points for birds.

3.118 Routine cleaning and good housekeeping will reduce the potential for the facilities to provide an attractive environment for vermin and this will be implemented through the maintenance programmes. In the event that pests are identified, an action plan will be developed to eliminate or reduce the potential for nuisance to neighbours.

3.119 Daily visual checks will be undertaken of the waste storage areas and EfW tipping hall / waste bunker area, as well as the access road and the site generally. If pests are reported appropriate measures will be taken and pest control specialists utilised where necessary. In addition to these measures, the EfW tipping hall will be washed periodically and standard pest control methods will be implemented.

Litter controls

3.120 All vehicles carrying waste into or out of the EfW facility will be covered or sheeted, thereby ensuring the potential for litter to escape is minimised. The delivery and storage of all waste within buildings on site further minimises the potential for wind-blown litter to occur. A daily check will also be made to key areas of the site (e.g. the tipping hall) to identify any build-up of waste. These combined measures will ensure that control of litter is maintained at all times.



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Community relations

3.121 Lakeside EfW Ltd operates a good neighbour culture which it applies to its existing Lakeside Road site and facilities, and which will be applied to the replacement Lakeside EfW and HTI facilities. Implementation of this culture includes the maintenance of a local liaison group, which meets on a regular basis to discuss the operation of the plant and any potential issues or queries that those in the local community have. It provides a forum for community stakeholders to be informed and consulted regarding site operations and procedures. Liaison group members will continue to include locally elected representatives of the community as well as representatives of the Environment Agency, SBC and other stakeholders as appropriate.

Environmental management

3.122 The existing EfW and HTI facilities at Lakeside Road are both currently certified to ISO14001 Environmental Management System with the BSI accreditation body. They also meet ISO9001 Quality Management and OHSAS18001 Occupational Health and Safety requirements. These quality management systems will be implemented at the replacement Lakeside EfW and HTI facilities, thus indicating Lakeside EfW Ltd’s aim to achieve the highest practical standards of quality, safety, occupational health and environmental control and performance at the replacement site.

Construction

EfW and HTI construction programme

3.123 A construction contractor will be appointed to design and build the EfW and HTI facilities. The total site preparation and construction programme for the EfW and HTI facilities is expected to last for approximately 36 months (early 2020 – late 2022), with a twelve-month commissioning and testing period immediately following (2023) (this is longer than usual as only one line of the EfW will be commissioned at a time). The anticipated programme for construction activities is as follows:

• 2020 – 2021 Construction of new junction on the A4 and new access road

• 2020 – 2021 Civil works (including: mobilisation period, plant preparation, landfill clearance, site leveling, set up of construction compound, laying foundations for waste bunker, boiler areas, flue gas treatment areas, construction of internal site roads and car parking, etc.)

• 2021 – 2022 External works (including: access area available for boilers and tower cranes, construction of weighbridge area, laying of underground cabling and provision of external security, etc.)

• 2020 – 2022 Erection of plant equipment (including: installation of various tower cranes, assembly and erection of boilers, FGT plant, furnace grates, refractories and thermal insulation, conveyor systems, bag filters, stack installation, silo installations, ducts / connecting pipework, air cooled condensers, steam turbine, transformer and associated cabling, etc.)

• 2021 - 2022 Steel structure and cladding (including: steel super structure for EfW and HTI buildings, cladding for both buildings, installation of solar panels, etc.)



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• 2023 Commissioning and plant take over (including: high voltage power ready to start pre-commissioning, pre-commissioning and cold test period (i.e. cold commissioning), hot test period (i.e. hot commissioning), operability test)

Site preparation, demolition and construction activities

3.124 Some preliminary enabling works, including the formation of the new junction off the A4 Colnbrook bypass and a temporary construction drainage scheme, will be undertaken prior to the main works commencing.

3.125 The temporary construction compound will be created to the south of the main site. This will contain the laydown area for plant, storage area for materials and the parking area for contractors. The perimeter of the construction site (including the temporary construction compound) will be fenced to provide secure boundaries. A security system will be installed to prevent unauthorised access to the site.

3.126 Once all the enabling works are complete, the stripping of any remaining topsoil from the northern half of the main site will commence; this will be stored for re-use as landscape material if possible. The excavation areas for the rest of the main site and the access road will also be marked out.

3.127 The site has a history of contamination, with the southern half of the main site, the temporary construction compound and the access road all being located on a former landfill site. Some of the material present in this area will therefore need to be exported off site and disposed of at authorised landfill facilities depending on the nature of the waste extracted (to be determined following a detailed contaminated land investigation).

3.128 The first phase of construction will involve construction of the new access road, the initial portion of the internal site road and the batters around the site. This is likely to take approximately 12 months. Standard road construction methods will be used to construct the new access road and the associated junction on the A4 Colnbrook bypass. Once the new road is operational, the kerb line along the A4 will be reinstated and the road verges restored to grass.

3.129 The proposed access road will cross an existing public right of way (bridleway 2a) that connects Colnbrook to Richings Park. Construction works will be securely segregated from the bridleway during construction of the road under the requirements of Traffic Signs Manual Chapter 8 (2009) or Safety at Street Works and Road Works - A Code of Practice (2013). Members of the public using the bridleway will be protected from the works and vehicular traffic by means of continuous barriers that clearly delineate and warn pedestrians of the works’ presence. Where the bridleway crosses the access road, a Temporary Traffic Regulation Order or Temporary Traffic Notice will be provided. This will be discussed in full with Slough Borough Council in due course. The width, surfacing materials and continuous barrier type will be appropriate for all users of the bridleway, including equestrian users.

3.130 Due to the nature of the ground conditions it is considered likely that pile foundations will be required for the majority of the EfW and HTI plant. Determination of the suitable piling technique to be applied will be carried out



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following additional geotechnical and contaminated land investigation work that is scheduled post planning.

3.131 Construction of the EfW and HTI buildings will take place simultaneously. The key construction activity initially will concentrate on the construction of the EfW waste bunker and foundations for other key areas of plant. Following the completion of the bunker walls in the EfW and equipment foundations and floor slabs for both buildings, work will commence on the erection of the process plant, which will be handled by large crawler cranes or tower cranes. Once this is complete the building steelwork can be erected.

3.132 Following the installation of the main process plant for both the EfW and HTI, and the construction of the enclosure steelwork, the installation of the cladding will take place. Cladding will be erected using long reach tower cranes. During this time the mechanical and electrical building services will be installed.

3.133 The final elements of work will be the installation of the external circulation roads, car parking areas and landscape works.

3.134 It is assumed that the off-site grid connection (both the temporary and long term connections as stated previously) will involve the excavation of a trench along existing or new roads / paths. It is likely that the installation contractor will seek to open as much trench at a time as possible so that suitable ducts can be laid quickly. Once the trench is backfilled and reinstated the electricity cable will be drawn through the ducts.

3.135 The framework CEMP provided in technical appendix C sets out the high level mitigation measures that will be applied during the site preparation and construction period to avoid adverse impacts on the receiving environment (e.g. provision of a wheel-wash at the entrance to the site to ensure that any construction vehicles leaving the site do not dirty the surrounding roads).

Construction employment

3.136 The number of people employed on site at any one time will vary considerably, but it is estimated (based on experience with similar projects elsewhere) that the average will be 420 over the 36-month construction period and 120 over the 12-month commissioning period. It is anticipated that there will be a peak in employment during months 16 – 21, during which up to 750 construction workers could be on site, as indicated in figure 3.18.

3.137 Skilled labour will be supplied by the sub-contractors. It is not known at present how many will be from the local area. All labourers not employed locally are likely to stay in local guest houses.

Site preparation and construction traffic

3.138 All site preparation and construction traffic will access and depart the site either westbound via the A4 Colnbrook bypass, London Road and the M4 or eastbound via the A4 Colnbrook bypass, Stanwell Moor Road, the A3113 and the M25. No construction vehicles will pass through Colnbrook village to the south of the A4.



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3.139 Based on experience of similar projects elsewhere it is predicted that site preparation and construction activities will generate, on average, 84 HGV movements each way per day (i.e. 168 HGV movements in total). Peak HGV movements are anticipated during months 10 – 12, when there is likely to be around 170 HGV movements each way per day (i.e. 340 HGV movements in total). HGV movements associated specifically with the removal of the landfill and the provision of fill materials has been estimated at around 42 HGV movements each way per day (i.e. 84 HGV movements in total) during months 1 – 3 of the site preparation and construction programme. Figure 3.19 provides a more detailed breakdown of the likely vehicle movements anticipated over the site preparation, construction and commissioning periods. It is assumed that HGV movements will be spread over the course of the working day, with a maximum of 20 HGV movements per hour.

3.140 Additionally, the movement of construction staff will result on average in 280 vehicle movements each way per day (i.e. 560 vehicle movements in total) and 500 vehicle movements each way per day (i.e. 1,000 vehicle movements in total) during the peak construction period (months 16 - 21). In line with standard practice, for the purposes of assessment it has been assumed that there will be 1.5 construction workers per car. All construction staff will park on site (within the temporary construction compound) and as staff will be working shifts, it is assumed that construction staff movements to and from site will occur mainly between the hours of 07:00 – 09:00 and 17:00 – 19:00 hrs. The framework construction environment management plan (CEMP) (technical appendix C) highlights measures intended to reduce vehicle trips.

Work hours

3.141 Construction work audible outside of the site boundary will take place during standard hours, e.g. 07:00-19:00 hrs Monday-Saturday, with no work on Sundays or public holidays. Delivery of oversize plant and equipment, internal fit out, internal works and other non-intrusive works may take place outside of these times. Extraordinary events such as concrete pours may also need to take place outside these hours as by their nature they need to be continuous.

Procedures for storing, handling and haulage of construction waste

3.142 Detailed procedures for the removal, temporary storage, handling and haulage of the landfill, excavation, demolition and construction waste will be developed once further design and survey work has been completed, the nature of the waste material is fully understood and routes for recycling and disposal of waste material are established. All procedures will adopt best practice and ensure that materials are safely handled whilst fully mitigating any risk of pollution to the environment or any contamination, which may jeopardise effective reuse or recycling. The framework CEMP covers waste management and is based on a number of key concepts that aim to manage and reduce construction waste.

Environmental protection measures during construction

3.143 In order to effectively manage environmental impact and nuisance control an environmental risk assessment will be undertaken of all construction activities (over and above that undertaken as part of the EIA process). The risk assessments will prioritise the risks to the environment and the potential



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consequences if the risk is realised. Control measures will be introduced in order to remove or reduce the risk to an acceptable level. The detailed CEMP that will be prepared in due course will cover all construction activities. The CEMP will encompass standard best practice approaches to construction and all the relevant mitigation measures identified by the EIA process and set out in this ES. Typical environmental and nuisance considerations and proposed control measures are presented in the framework CEMP (technical appendix C).

Commissioning

3.144 Commissioning / testing of the EfW and HTI facilities will commence following completion of the civil works and the erection and installation of all equipment, and is likely to take approximately twelve months as it is planned to commission one line of the EfW at a time. Lakeside EfW Ltd will agree a written commissioning programme with the Environment Agency, which will also describe the commissioning protocols with regard to meeting regulatory requirements, e.g. noise monitoring, emissions monitoring and the calibration / verification of CEMS equipment.

3.145 Commissioning will take place in two stages; 'cold' and 'hot' commissioning. Cold commissioning of the facilities involves confirming that all items of plant and equipment function as intended. This will include line checking, rotation checking, electrical testing, calibration, etc. It will also include testing of any computer control systems, validation of safety systems and interlocks, and interfaces with external services. Cold commissioning will occur before waste is delivered to the EfW and HTI facilities. Hot commissioning will involve operating the EfW and HTI facilities with waste and verifying that the waste treatment technologies achieve their desired aims.

3.146 At the end of hot commissioning the EfW and HTI facilities will then undergo performance testing to verify that the facilities achieve their contractual performance requirements. On satisfactory completion of the performance tests, the facilities will be presented for independent certification. Once the tests are complete and the certificates issued, the facilities will be deemed ready for full service commencement.

Demolition / decommissioning

3.147 In the event that Heathrow Airport Ltd’s airport expansion proposals are not consented or Heathrow Airport Ltd does not wish to proceed with their expansion plans, the replacement EfW and HTI facilities and access road must be demolished, removed and the site reinstated to open grazing land. For the purposes of the assessment, it has been assumed that demolition, site clearance and reinstatement activities and associated vehicle movements (both HGVs and staff) would be of a similar nature / number to those outlined above in relation to site preparation and construction. It is also assumed that the same environmental management and control measures that will be set out in the outline CEMP will also apply to any demolition, clearance and site reinstatement activities. It is anticipated that the demolition of the buildings, removal of the plant equipment and reinstatement of the site back to open grazing, would take approximately 2-3 years.

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Figure 3.1 Site layout

Ordnance Survey © Crown Copyright 2018. All rights reserved. Licence number 100022432

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Figure 3.2a and b 3D images of the EfW and HTI buildings

a) View looking west across staff and visitor parking

b) 3D section view of west elevation of main building cut along internal street

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Figure 3.3a Proposed elevations: EfW building


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Figure 3.3b Proposed elevations: EfW building


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Figure 3.4a Longitudinal sections of the EfW


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Figure 3.4b Longitudinal sections of the EfW


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Figure 3.5a Proposed elevations: HTI building

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Figure 3.5b Proposed elevations: HTI building

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Figure 3.6 Longitudinal sections of the HTI

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X02 X01X03X04X05X06 /AA TH-ZZ-DR-A-200

00 Ground FloorFFL

0.000

U/S CladdingPlinth3.000

Y01

Roof Low LevelU/S

15.500

Y03Y04 Y02

01 First FloorFFL

5.000

Y05

-01 - C. PumpFFL

-2.500

/BB TH-ZZ-DR-A-200

00 Ground FloorFFL

0.000

U/S CladdingPlinth3.000

Y01

Roof Low LevelU/S

15.500

Y03 Y04Y02

01 First FloorFFL

5.000

Y05

-01 - C. PumpFFL

-2.500

/BB TH-ZZ-DR-A-200

X02X01 X03 X04 X05 X06/AA TH-ZZ-DR-A-200

KEY TO MATERIALS

A - PLINTH WALL - Split face blockwork natural white + grey band

B - CLADDING - Metal cladding grey Sirius RAL 9006 from Eurogroup G Series Architectural Cladding

C -

D -

E -

F -

ROOF - Euroseam Roof from Euroclad with Organic Patina Aluminum standing seam and 'Dull' finish

LOUVRES - Steel colour-coated grey RAL 7012

ROLLER SHUTTER DOORS - Aluminium colour blue RAL 5010

OTHER DOORS - Steel doors colour matt grey RAL 9006

Rev

Revision date

Drawing number

First Issue Date

Org Project number

Scale

Client

Project Name

Drawing name Suitability

Drawn by Check by

PELHAM HOUSE 25 PELHAM SQUARE BRIGHTON BN1 4ETT: 01273 695535 www.crowtherassociates.co.uk

CROWTHERASSOCIATES ARCHITECTS LLP

As indicated

C1816 - CAA - TH - ZZ - DR - A - 300 S1

10/05/19

CAA 1816

MN JJLakeside 2

Lakeside EFWTH - Elevations

0 1 32 4 5 10

SCALE IN METERS

1 : 100

East Elevation1 : 100

North Elevation

1 : 100

South Elevation1 : 100

West Elevation

B

E

C

A EF A

B

C

B

C

A

C

B

AF

Figure 3.7 Proposed elevations: turbine building

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Figure 3.8 Longitudinal section of the turbine building

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Figure 3.9 Proposed elevations:air cooled condensers

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A3113

A3044

M4

B470

A4

M25

M25

ILakeside EfW Ltd

Drawn by:

JCChecked by:

ER

Contains OS data © Crown copyright and database right 2018. Licensed under the Open Government Licence v3.0 Licence No. 100019980.

Copyright Terence O'Rourke Ltd, 2019

29 May 2019

Scale: 1:20,000 @A3

Routes to be taken byconstruction HGVs

Planning application boundary

Revision

227705/09

Local highway network

Replacement Lakeside EfW and HTI Facilities

Status

0 500 mN

Enterprise House 115 Edmund StreetBirmingham B3 2HJ

BIRMINGHAM

www.torltd.co.uk

TELEPHONE020 3664 6755

Everdene House Deansleigh Road Bournemouth BH7 7DU

BOURNEMOUTH

7 Heddon Street London W1B 4BD

LONDON

Figure 3.10 Local highway network

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Figure 3.11a Proposed new junction and site access road

Contains public sector information licensed under the Open Government Licence v3.0. Published by The Environment Agency

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Figure 3.11b Proposed new junction and site access road

Contains public sector information licensed under the Open Government Licence v3.0. Published by The Environment Agency

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xoodxxoodx

2 stream EfW

Waste bunker

Staff / visitor parking

Main EfW / HTI

vehicle entrance

FGT

HTI loading bay

TurbineMaintenance workshops

Switch gear

Transformer

Maintenance car park

Heat station

01

Heat station

02

Education centre

Offi

ce

entra

nce

RA

MP

KJ KJKJ

FF

F FStaff

/visitor entrance

(occasional use by HTI vehicles)

KJ

I

F

FF

F B

H H

AA

HF G

EA C

G A

GG

HI

F

D

BC

DB

IF

E

CE HF

CE A

A

G

CEBA

DC

FE

G

IH

BA

DC

FE

G

IH

F

ABCDEFGHIJK

Waste truckBottom ashARCrDiesel oil truckLime /activated carbon truckMaintenance truckCMI truckHLC/NaOJ/Ammonia truckMetal recycling truckStaffVisitorHTI

Ash bunker

Figure 3.12 On-site vehicle circulation

based on drawing by


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Permanent site boundary

Application site boundary

Proposed trees

Retained trees

Removed trees

Removed planting

Proposed native planting mix

Proposed grass seeding

Proposed shrub planting

Based upon the 2017 Ordnance Mastermap vector data with the permission of the Ordnance Survey on behalf of Her Majesty’s Stationery Office © Crown copyright. Terence O’Rourke Ltd Licence No. 100019980.

© Terence O’Rourke Ltd 2019.

N0 100 m

Figure 3.13a Site landscape scheme

3.13a

3.13b

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Permanent site boundary

Application site boundary

Proposed trees

Retained trees

Removed trees

Removed planting

Proposed native planting mix

Proposed grass seeding

Proposed shrub planting

N

Based upon the 2017 Ordnance Mastermap vector data with the permission of the Ordnance Survey on behalf of Her Majesty’s Stationery Office © Crown copyright. Terence O’Rourke Ltd Licence No. 100019980.

© Terence O’Rourke Ltd 2019.

100 m

210

Figure 3.13b Site landscape scheme

3.13b

3.13a

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* Quantity may vary depending upon waste composition

RESIDUAL WASTE 440,000 tonnes

per annum

AIR POLLUTION

control chemicals

AIR POLLUTION RESIDUES

BOTTOM ASH

NET ELECTRICITY 44 MW

HEAT (up to 20 MWth steam / hot water)

ELECTRICITY NETWORK (39 MW)

LOCAL CUSTOMERS

RECYCLING(sustainable aggregate)

RECYCLING

ENERGY from

WASTE

RECYCLING(sustainable carbon neutral aggregate)

EfW

Figure 3.14 EfW inputs and outputs flow diagram

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LAKESIDE EFWProcess flow diagram

1 Waste delivery 2 Waste collection pit / bunker 3 Combustion air fan 4 Burning mass 5 Super heater 6 Boiler

7 Flue gas treatment (FGT) 8 Carbon and lime injection 9 BAG plant 10 Air pollution control residues

(APCr)11 Induced draft fan12 Continuous emission

monitoring system (CEMS)

13 Stack 14 Recovered metals 15 Incinerator bottom ash (IBA) 16 Electricity generator

ST Steam turbine G GeneratorTX Transformer

TREATMENT / SECONDARY AGGREGATE PROCESSING

OUTLETFOR CHP

RECYCLING

Figure 3.15 EfW process flow diagram

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HTI WASTE 10,000 tonnes

per annum

AIR POLLUTIONcontrol chemicals

HIGH TEMPERATUREINCINERATOR

LOW PRESSURE STEAM(sent to EfW plant

to improve efficiency)

BOTTOM ASH

AIR POLLUTION CONTROL RESIDUES

RECYCLING(secondary aggregate)

LANDFILL

HTI

Figure 3.16 HTI inputs and outputs flow diagram

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1100oC - 1000oC

PRE FILTERMONITORING:

6%

ID FAN

55m STACK

Figure 3.17 HTI process flow diagram

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800

750

700

650

600

550

500

450

400

350

300

250

200

150

100

50

0

30

Construction employment

Note: Construction employment

In the absence of an appointed contractor assumptions have been made on construction employment on the basis of experience of similar projects elsewhere. The figures in the above chart were derived from the passenger vehicle construction traffic figures shown in figure 3.21 and the assumption that there will be 1.5 construction workers per vehicle.

150

300

510

660

750

750

660

555

360

210

120

120

120

120

120

Peak employment

Construction programme

Year 1 Year 2 Year 3 Year 4

2020 2021 2022 2023

2020 2021 2022 2023


Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Civil Construction

Mechanical erection

Cold commissioning

Hot commissioning

Figure 3.18 Indicative construction programme and employment

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FOLD

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1000

950

900

850

800

750

700

650

600

550

500

450

400

350

300

250

200

150

100

50

0

260

200

60

40 0 0 0 0 0 0 2 0 4 0 6 0 4 0 4 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0

200

200

200

400

240

240

680

340

340

880

250

250

1000

250

250

1000

160

160

110

110

880

740

480

90 90

48 48

280

160

160

14 1414 14

160

14 14

160

14 14

160

14 1424 24

Traffic Movement Type (All traffic movements are too and from site unless indicated otherwise)

Note: Construction traffic

In the absence of an appointed contractor assumptions have been made on construction traffic on the basis of experience of similar projects elsewhere. Assumptions include:

• A three-year site preparation and construction programme, plus a one-year commissioning programme. The latter is longer than usual due to the proposed commissioning of one line at a time.

• All materials entering and leaving the site during the construction phase will do so by road.

• A vehicle movement is defined as a vehicle arriving or leaving the site (e.g. 1000 passenger vehicle movements per day = 500 movements to the site and 500 movements from the site).

• The passenger vehicle movements are predicted from a peak workforce of 750 workers, with an estimated 1.5 personnel per vehicle based on assumptions used for similar projects.

• Due to shift working patterns it is assumed that construction workers will arrive at the site between the hours of 07.00-09.00 and depart between the hours of 17.00 – 19.00.

• HGV movements are expected to be spread over the course of the working day, with a maximum of 20 HGV movements per hour.

• The figures do not allow for any special one-off significant concrete pour events as it is not known at this stage whether this will be required by the contractor or whether concrete will be batched on site rather than delivered pre-mixed. The need for such special events would be discussed and agreed with SBC beforehand if required.

• For a typical EfW / HTI project it could be assumed that, further to landscaping requirements, up to 30,000 m3 of soil would be expected to be removed from site during the earthworks phase. Using an assumed soil density of 1,850 kg/m³ and an assumed vehicle payload of 30 tonnes, the total number of additional vehicle movements required would be 1,850. Assuming that it takes no less than 10 minutes to fill a vehicle, an additional 120 vehicle movements would occur each

day over an assumed ten-hour working day (e.g. 08:00 to 18:00). However, as the proposed replacement site is not a typical site and includes landfill that requires removal, as well as fill that may not be able to be derived on-site, an additional 80 movements (40 to the site and 40 from the site) have been included for the first quarter of year 1, when site preparation activities will be underway, bringing the total to 200. The additional vehicle movements themselves are based on a series of assumptions as follows: (1) total cut tonnage is based on soil density of 1,850 kg/m³ and is calculated to be 65,108 tonnes for road and the main site (2) total fill tonnage is based on a soil density of 1,850 kg/m³ and is calculated to be 57,817 tonnes for the road and main site (3) volumes have been calculated based on the existing and proposed surface levels (4) an additional 600mm

depth of excavation for road and EfW site construction build up has been allowed for (5) no allowance has been made for building foundations as this cannot be estimated at this stage (6) no allowance has been made for site wide drainage ditches or over-digging of earthworks (in relation to capping of the landfill material) at this stage, and (7) all the cut material is assumed to be landfill (although this may not be the case).

• It is assumed that the soil removal will be completed in the first quarter of the construction program rather than stored on or adjacent to site.

• Several abnormal loads are expected during the construction phase for turbine, generator, boiler panels and tanks. These are expected to peak at six deliveries per day during the peak construction period. The abnormal loads are expected to occur during the mechanical and process construction phase in the second year of the construction program. The return vehicles from site are assumed to be classed as a normal HGV load rather than an abnormal loads.

1) Passenger Vehicles

2A) HGVs for general bulk deliveries or collections (incl. concrete deliveries)

2B) HGVs for cut and fill deliveries and collections

2) Combined HGVs (2A + 2B)

3) Abnormal loads (daily delivery to site only)

Peak passenger vehicles

Peak HGVs


2020 2021 2022 2023

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Figure 3.19 Estimated construction traffic

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