Thames Water

Mogden Sewage Treatment Works

Residents Liaison Meeting

7 March 2012

Thames Water

Agenda

� Review of previous minutes

� Operations and communications

� Talk: Mogden Plan 2021 and Beyond

� Mosquito survey results

� Sewage Treatment Work Upgrade Project – an update

� AOB

Thames Water

Operations and communications

Thames Water

Operations update

� WAMI (Work, Asset Management and Information) has been introduced at Mogden

� The planning of work carried out by Technicians on site is now fully automated and will ensure the right person is in the right place at the right time with the right tools

� New handheld devices will record all work carried out on our assets which will allow robust future investment decisions to be made

� Enables seamless integration of Operations and Maintenance functions

Thames Water

Operational Correspondence2009 – 2012

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OtherMosquitoesOdour and mosquitoesOdour

Thames Water

Notifications December – Present

December 2011� Mogden Upgrade – Christmas construction activity

January 2012� Mogden Upgrade – construction update

February 2012� Mogden Update newsletter – general notification� Primary tank drain down – a precautionary notice � Mogden Upgrade – construction update� Primary tank drain down – a precautionary notice

March 2012� None

Thames Water

Communications update

� Our latest Mogden Update newsletter went out in February 2012

� A new interpretation board has been installed in the middle of the public footpath that runs through Mogden telling passers by about the sewage treatment process

Mogden STWInvestment Plan 2021

and Beyond

2

Thames Water’s obligations

� Legal requirement to effectively drain and treat sewage

including planning for population growth

(Section 94 Water Industry Act 1991)

� Legal requirement to meet water quality discharge standards

set by the Environment Agency

(Urban Wastewater Treatment Directive)

� Regulatory requirement to maintain stable serviceability of our

assets and processes (Ofwat)

� Provide good value for money for our customers

3

History of Mogden STW

� 1930’s – A and B batteries were constructed as part of the West

Middlesex Drainage Scheme

� 28 small STWs were closed and replaced with a large trunk sewer

system draining to Mogden STW

� 1960’s – C battery was constructed

� 1999 – D battery was constructed

� 2011 E battery is being constructed, anticipated completion date in 2013

4

Drivers for expansion

Population growth

� London’s population is expected to increase over the next

10 - 20 years

� Increases in volumes of wastewater will require treatment

and storage using more or larger tanks

Water quality obligations

� Continual improvement of the River Thames through more

stringent water quality obligations

� Solutions to meet these standards often requires more or

larger tanks to increase treatment capability

5

2011 – 2021

� Current extension project is designing to a 2021 horizon

� Designed with some headroom likely to accommodate growth until 2026

� 2010 London Plan housing target of 62,300 additional units

� Predicted population increase of 149,500

6

2011 – 2021

� Current upgrade is to meet a new suspended solids and

more stringent ammonia and BOD discharge standard

� Improved quality of final effluent

� Increased capacity will reduce the frequency of storm

discharges to the River Thames

� Potential future requirements include chemical treatment

using nitrogen, phosphorus

� The EA has not yet made a decision about these therefore

there is uncertainty about future quality requirements after

2016

7

Post 2021

� Continued population growth post 2021 is difficult to forecast accurately

� GLA forecast of 6% from 2021 up to 2031

� Predicted population increase of 144,100

2021 - 2031 GLA Population Forecast

1950000

2000000

2050000

2100000

2150000

2200000

2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031

population

8

Post 2021

� Uncertainty in population growth forecasts and new quality

obligations

� The water industry undertakes medium term planning in 5

year AMP cycles

� Water efficiency is forecast to increase due to more

environmentally efficient homes and water saving initiatives

– this will reduce flows

� Sustainable urban drainage and the removal of surface

water from the foul sewers – this will reduce flows

� There will still be a net increase in flow and load

(concentration of waste matter)

9

Post 2021

� Mogden will continue to be the main treatment works for all

sewage coming from the existing catchment

� Mogden will continue to meet all quality standards set by the

Environment Agency

� Some land is available for a post 2021 expansion if necessary

� Innovative solutions to increase treatment capacity - doing

more with what we have rather than building more

� Save customers money and minimise our carbon foot print

� All options will be investigated before an investment decision is

made – Best whole life cost option

� Continue to work with our neighbours and regulators on

managing and minimising odour

Thames Water

Mosquito Survey Results

Thames Water

Guide to week numbers – 2012

January Weeks 1 – 5February Weeks 5 – 9March Weeks 9 – 13April Weeks 13 – 18May Weeks 18 – 22June Weeks 22 – 26July Weeks 26 – 31August Weeks 31 – 35September Weeks 35 – 39October Weeks 40 – 44November Weeks 44 – 48December Weeks 48 - 52

Thames Water

Mosquito data- Number of sites inspected

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Average 03-07 2008 2009 2010 2011 2012

Thames Water

Mosquito data- Percentage of sites showing any activity

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Average 03-07 2008 2009 2010 2011 2012

Thames Water

Mosquito data- Percentage of sites showing any adults

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Average 03-07 2008 2009 2010 2011 2012

Thames Water

Mosquito data- Percentage of sites with many adults

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Thames Water

Mosquito data- Percentage of sites with many adults (2)

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Thames Water

Mosquito data- Percentage of sites with larvae activity

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Average 03-07 2008 2009 2010 2011 2012

Thames Water

Sewage Treatment Works Upgrade Project – an update

MogdenMogden

UpgradeUpgrade

Key progress to date

� Most of the civil engineering work - such as building foundations and

tanks – is now complete.

� This means our noisiest construction activities are over.

� The focus of our work continues to be on mechanical and electrical

installation.

� We have started reducing the western embankment to its final height,

which will be carried out in phases until completion in the autumn.

Inlet works

This is where we filter the sewage to remove grit and other large items.

� The structures are complete and most of the mechanical equipment has been installed.

� We are currently installing the odour control covers, and the power supply to the new equipment.

� We will commission the new inlet works in the spring.

Inlet works (cont)

Primary settlement tanks

This is where solids settle to the bottom and are then removed.

� The main structures are

complete and all the

associated mechanical

equipment has been

installed.

� We are now working on

connecting the new covered

tanks to the new odour

control unit and finishing the

electrical infrastructure.

� We will start commissioning

in the spring.

Aeration lanes

This is where we encourage bacteria to eat the organic matter.

� All five new lanes are

complete.

� 1000 pre-cast panels have

been used to create the

lanes, reducing the number

of deliveries to site and

impact on local traffic.

� We are now constructing

the Intermediate Pumping

Station.

Final settlement tanks

This is where the remaining solids are removed before the effluent is returned to the River Thames.

� Eight of the ten new final tanks have been built.

� The remaining two tanks will be finished this month.

� Backfilling has started around the FSTs (see picture)

Sludge stream

This is where the remaining sludge is broken down and turned into energy.

� Five new gas compressors

and a new raw sludge

holding tank are now

operational.

� 11 of the 16 digesters

have been refurbished.

� This work will allow us to

power up to 40 per cent of

the new extension with

renewable energy.

New odour control units (OCU)

We are installing two new odour control units as part of this project:

� OCU no.11 will control the odour for the new Inlet works and primary tanks. Installation will be complete around spring 2012 when it will be fully commissioned.

� OCU no.12 will control the odour for the new sludge stream. We will soon start building this, which will be complete by the end of 2012.

The western embankment

� We’ve started removing the earth temporarily placed on the mound, meaning the embankment will be back to its original height in the autumn.

� At this point we will start planting the embankment and surrounding area with native trees, shrubs, and herb-rich grassland including wildflowers, encouraging biodiversity and improving our neighbours outlook.

Electrical infrastructure

� As part of the upgrade

we are also upgrading

the electrical

infrastructure.

� We recently took

delivery of two new 40-

tonne transformers.

� In conjunction with the

renewable energy that

we generate on site,

these will provide

enough electricity to

power the entire works.

In the community – Thames 21 clean-up

� Thames Water

and Black &

Veatch staff

volunteered with

Thames 21 in

February.

� Cleared litter and

debris from river

bed around

Isleworth Ait.

� Similar events

planned for

coming months.

Tour of upgrade works

� Dates available to tour of new works are as follows:

� Thursday 12 April

� Thursday 19 April

� Thursday 26 April

� There are two time slots available:

� 10am to 12.30pm

� 2pm to 2.30pm

� All attendees will receive a Health & Safety induction ahead of the tour

� An invitation will be sent out and joining instructions will follow

Thames Water

AOB

Thames Water

Proposed dates of meetings:

� Wednesday 6 June 2012

� Wednesday 5 September 2012

� Wednesday 5 December 2012

Thames Water

Need to contact us about Mogden?

Call the Mogden 24hr line (via the Thames Water

Operations Contact Centre):

0845 641 0030

To subscribe to email notifications, email us at:

mogden@thameswater.co.uk

Visit our website:

www.thameswater.co.uk/mogden

Write to us:

Customer FeedbackPO Box 286

SwindonSN38 2RA