Osmosis Manual English

User Manual for Seawater Reverse Osmosis Plant SRO-250 1 GENERAL INFORMATION

Index I 1 General Information 1.1 How Reverse Osmosis Works 1.2 How to Use Reverse Osmosis 1.3 Reverse Osmosis Membrane and Module Designs 1.3.1 Spiral Wound Elements 1.4 Reverse Osmosis System Design 1.4.1 Feedwater Pretreatment 1.4.2 Fouling 1.4.2.1 Membrane Scaling 1.4.2.2 Metal Oxide Precipitation 1.4.2.3 Device Clogging 1.4.2.4 Colloidal Fouling 1.4.2.5 Biological Fouling 1.4.3 Pretreatment Section 1.4.4 Desalination Section 1.4.5 Post-Treatment Section 1.5 Factors Influencing Reverse Osmosis Performance 1.5.1 Pressure 1.5.2 Temperature 1.5.3 Feedwater Salt Concentration 1.5.4 Recovery 2. System Description 2.1 Process Description 2.1.1 Feedwater Inlet 2.1.2 Filtration (disc filter unit) 2.1.3 Dechlorination (NaHSO3 dosing) 2.1.4 RO-membrane protection ( Dosing Scale Inhibitor) 2.1.4.1 Fine Filter (cartridge filter) 2.1.5 Reverse Osmosis System 2.1.5.1 High Pressure Pump 2.1.5.2 Modules (Pressure Vessels and Membrane Elements) 2.1.6 Clean Water System 2.1.7 Brine System (Concentrate) 2.1.7.1 Flushing Tank [B3] 2.1.8 Flushing and Circulation Cleaning System 2.2 Technical Data 3.0 Function of the Main Components 3.1 Disc Filter 3.1.1 Technical Data 3.1.2 operating the filter equipment 3.1.3 backwashing the filter equipment 3.1.4 First Filling with Water 3.1.5 Maintenance 3.2 Dechlorinator (NaHSO3 dosing unit) 3.2.1 Technical Data dosing equipment for dechlorination 3.2.2 Dosing System for Scaling Inhibitor

3.3.1 Technical data 3.4 Fine Filter 3.5 High Pressure Pump 3.6 RO-Modules 3.6.1 Adjustment of the RO-System


3.7 Flushing and Cleaning System 3.8 Chlorination dosing unit 3.8.1 Technical data 3.9 EMSR Electronic Measuring and Control Equipment

4 System Operation Instruction 4.1 Safety Instructions 4.1.1 Noises 4.1.2 Sources of Danger 4.2 Commissioning and Start Up 4.2.1 Requirements 4.2.2 Requirements before Start Up 4.2.2.1 General Information 4.2.2.2 Removal of Conservation 4.3 Manual Start Up 4.3.1 Requirements 4.3.2 Execution 4.4 Shut Off 4.5 Automatic Start Up 5 Measuring and Control Equipment 6 Maintenance 6.1 Membrane Elements 6.1.1 Conservation 6.1.2 Reconservation 6.1.3 Exchange of the Module 6.1.4 Sampling 6.2 Operation log

7 Disturbance, fault analysis and repair hints

8 General Cleaning Instructions

9 Glossary of terms in water treatment


10 Documentation of individual components

1 general arrangement PID valve chart instrumentation list power consumption list design computing

2 general description for installation and commissioning

3 Drawing 4 program SPS program floppy disc OP7 5 control equipment wiring diagrams soft starter electrical parts floppy disc 6 membranes and pressure vessels 7 filters disc filters cartridge filter 8 aggregates booster pump high pressure pump rinsing pump dosing pumps 9 armatures 10 measuring and regulation instruments temperature conductivity Redox potential flow level pressure 11 common spare part list 12 safety data sheets 1 certificates

User Manual for Seawater Reverse Osmosis Plant SRO-250 1 GENERAL INFORMATION General Information This manual describes how the unit should be operated and maintained. It also contains some general information on the reverse osmosis process. The operating and safety instructions of this manual must be observed carefully. The SRO unit is shipped workshop-tested and ready for connection. Wrong operation or misuse may affect the performance and can involve :

• danger to life and limp of the operating staff, • damages to the SRO unit, • affect the quality of the produced water All persons involved in commissioning, operating, servicing, and maintaining the SRO unit must be adequately qualified and must be familiar with the content of this manual. Some sections of this manual incorporate special warnings. Underlined letters denotes the type of warning: DANGER!

Denotes an immediate danger. Disregard of this warning involves danger to life and limb. WARNING!

Denotes a potentially dangerous situation. Disregard of this warning involves danger to life and limb.

CAUTION!

Denotes a dangerous situation. Disregard of this warning can involve serious injuries. NOTE! Denotes tips and other useful information. Disregard of this warning involves danger to the SRO-unit and other property.


Important Phone and Fax Numbers

RWO Repair and Service

Tel. : + 49 421 5370535

Fax : + 49 421 5370540

RWO Spare Part Service

Tel. : + 49 421 5370518

Fax : + 49 421 5370540

RWO Eqipment Sales

Tel. : + 49 421 5370511

Fax: + 49 421 5370542

Important:

Please always specify the RWO order number and the equipment serial number.

User Manual for Seawater Reverse Osmosis Plant SRO-250 1 GENERAL INFORMATION 1.1 How Reverse Osmosis Works Osmosis occurs when pure water flows from a dilute saline solution through a membrane into a higher concentrated saline solution. The phenomenon of osmosis is illustrated in Fig.1.1. A semipermeable membrane is placed between two compartments, with a salt solution in one compartment and pure water in the other compartment. Semipermeable means that the membrane is permeable to some species, and not to others. Assume that the membrane is permeable to water, but not to salt. The membrane will then allow water to permeate through it to the other side.

As a fundamental rule of nature, this system will try to reach equilibrium. That means, it will try to reach the same salt concentration on both sides of the membranes. The only possible way is for water to pass from the pure water compartment to the salt-containing compartment, to dilute the salt solution. Fig. 1.1 also shows that under this condition osmosis can cause a rise in the height of the salt solution. This height will increase until the pressure of the column of water is so high that the force of the column stops the water flow. The equilibrium point of this water column height in terms of water pressure against the membrane is called osmotic pressure or osmotic head (see Fig. 1.1(b)). By application of a pressure in excess of the osmotic pressure to this column of water, the direction of water flow through the membrane can be reversed. This, shown in Fig. 1.1(c), is the basis of the reverse osmosis process. Note that the reversed flow produces pure water from the salt solution, since the membrane is not permeable to salt. 1.2 How to Use Reverse Osmosis Today reverse osmosis is a widely known and accepted versatile separation process. It can reduce the TDS of the feedwater by up to 99,9 %. In practice >95 % rejection is usual. Rejection of bacteria, viruses, and pyrogens is 100 %. After removal of suspended matter and pre-treatment reverse osmosis is suitable to upgrade seawater of up to 50000 ppm, brackish water, and saline wells to produce potable water. A simplified reverse osmosis process is shown in Fig. 1.2. Reverse osmosis is operated as a continuous process. With a high pressure pump, pressurised saline feed water is continuously pumped to the module system. Within the module, consisting of a pressure vessel (housing) and a membrane element, the feed water will be split in a low-saline product, called permeate and a high-saline brine, called concentrate or reject. A flow

Saltsolution

Purewater

semi-permeable membrane

Pressure

(c) Reverse osmosis(b) Osmotic equilibrium(a) Osmotic flowsemi-permeable membrane

Osmotic head(pressure)

Saltsolution

Purewater

semi-permeable membrane

Fig. 1.1 Principles of osmosis and reverse osmosis.

User Manual for Seawater Reverse Osmosis Plant SRO-250 1 GENERAL INFORMATION regulating valve, called concentrate valve, controls the percentage of feedwater that is going to the concentrate flow and the permeate which will be obtained from the feed.

1.3 Reverse Osmosis Membrane and Module Designs Four basic types of RO module designs are in commercial use: tubular, plate-and-frame, hollow fibre, and spiral wound modules. The first two designs seldom compete with spirals and hollow fibre modules in desalination and water purification. Of the two other element types the spiral wound elements are the most important for offshore and naval applications. Typically spiral wound configuration offers significantly lower replacement costs, simpler plumbing and greater design freedom than other configurations.

1.3.1 Spiral Wound Elements The design of spiral wound elements, Fig. 1.3, contains two layers of membrane glued back-to-back onto a permeate collector fabric (permeate channel spacer). This membrane envelope is wrapped around a perforated tube into which the permeate empties from the permeate channel spacer. A plastic netting is wound into the device to maintain the feedstream channel spacing .

One specific advantage of spiral wound elements is that they can be linked together into a series of two to seven elements within a single pressure vessel. Thus, up to seven times the flow of product water can be handled with only a single set of plumbing connections for feed, concentrate and permeate to a pressure vessel. In case of a spiral wound module consisting of a pressure vessel and several spiral wound elements, pressurised water flows into the vessel and through the feedstream channels between the spiral windings. The feed water becomes more and more concentrated and will enter the next element, and at last exits from the last element to the concentrate valve where the pressure will be released. The permeate of each element will be collected in the common permeate tube installed in the centre of each element and flows to the permeate collecting pipe outside of the pressure vessel.

Permeate

ConcentrateFeedwater

Concentrate valve

Module(Pressure vessel & element)

High pressure pump

Feed WaterChannel Spacer

Permeate Tube Permeate ChannelSpacer

Reverse OsmosisMembranes

Fig. 1.2. Reverse osmosis process

Fig. 1.3. Spiral Wound Element (Glue Line Dotted).

User Manual for Seawater Reverse Osmosis Plant SRO-250 1 GENERAL INFORMATION Spiral wound elements are standard devices for seawater desalination because they show a high rejection rate, low susceptibility to plugging and a wide pH and temperature range tolerance as well as relatively low purchase and operating costs.


1.4 Reverse Osmosis System Design In practice an entire RO water desalination system consists of the pretreatment section, the desalination section, and the post-treatment section. Pretreatment techniques are used to minimise fouling, scaling, and membrane degradation. Common techniques are filtration and chemical treatment for the adjustment of operating variables. Post-treatment is employed to achieve the required product quality.

1.4.1 Feedwater Pretreatment Pretreatment may be based on membrane considerations, such as dechlorination for poly-amide membranes or pH adjustment to prevent hydrolysis for cellulose acetate-based membranes. However the major pretreatment requirement for any reverse osmosis unit is the prevention of membrane fouling.

1.4.2 Fouling The phenomenon of fouling is complex, and is complicated because the word is used to describe several related problems. Fouling affects all types of membranes and devices, but this short review presents only basic concepts of fouling with respect to the reverse osmosis elements and techniques. All aspects of fouling involve the trapping of some type of material within the RO unit itself or on the surface of the membrane. Since causes, symptoms and cures are different, five potential problems should be considered:

1.4.2.1 Membrane scaling Membrane scaling is caused by the precipitation of some salts dissolved in the feedwater. Since the salts are concentrated in the reverse osmosis process, their solubility limits can be exceeded, and thus precipitation can occur. Three basic approaches are used to control scale: • Conversion control to avoid exceeding solubility. • Removal of one of ions responsible for a scale-forming compound. This can be achieved

by softening or addition of acid. • Inhibiting the crystal growth of a scale forming compound by addition of an inhibitor. 1.4.2.2 Metal Oxide Precipitation Soluble species in the feedwater can be oxidised in the reverse osmosis system ahead of the modules, or in the element itself, to form insoluble species which can then deposit in the elements. Iron is the prevalent cause for fouling by this mechanism. Iron fouling may be avoided by two approaches:

• Removal of the iron from the feed supply by clarification and/or filtration processes. • Prevention of oxidation from ferrous (soluble) to the ferric (oxidised) state.

1.4.2.3 Device Clogging Plugging is caused by mechanical filtration in which particles too large to pass through the feed-brine passage are trapped in the device. Most units however are adequately protected by the minimum-prefiltration system consisting of cartridge filters.

1.4.2.4 Colloidal Fouling • Colloidal fouling means the entrapment of colloids on the membrane surface and is

caused by the coagulation of the colloids during the reverse osmosis process. The two main parameters which control the rate of coagulation, and thus the rate of fouling, are:

User Manual for Seawater Reverse Osmosis Plant SRO-250 1 GENERAL INFORMATION • Concentration of colloids. There are several techniques which can be used to lower the

colloidal concentration to an acceptable level, .e.g. filtration, using sand, carbon, etc., or coagulation followed by sedimentation and gravity sand filtration.

• Stability of the colloids. In theory there are several techniques to stabilise colloids, but to date only ion exchange softening has proven practical.

1.4.2.5 Biological Fouling Biological fouling is caused by the growth of micro-organisms in the reverse osmosis system. The aromatic polyamide membranes used in the spiral wound configuration are completely impervious to bacterial attack. However, precautions should be taken to minimise bacterial proliferation in all types of permeators. For potable water the most commonly used biocide is chlorine. Feedwater containing chlorine should be de-chlorinated prior to the RO system, because chlorine reacts with the polyamide membrane material.

1.4.3 Pretreatment Section The pretreatment on ships would ideally adjust to the changing feedwater quality. However, the pretreatment is usually reduced to precautions against membrane scaling, colloid fouling and biological fouling. For seawater the only scalant encountered is calcium carbonate, and preventing its pre-cipitation is accomplished by pH adjustment to pH 6.0 - 6.5 or by addition of a scale inhibi-tor. With a recovery rate below 15 % scale prevention techniques are often unnecessary.

The stabilisation of the colloids is usually impractical. Thus only the reduction of the concentration of the colloids is used to control colloidal fouling. The minimum pre-filtration system used with most units consists of 5 or 10 µm cartridge filters. Prior to the cartridge filters additional pressure media filters may be installed to remove the bulk of the suspended matter and the colloids. The specification in regard to the Silt Density Index is less than 5 for spiral wound elements. Preautions used to prevent biological fouling on feed-brine side are ultraviolet sterilisation, sodium bisulphite shock treatment (500 ppm for 20-30 min once a day), and chlorination- dechlorination.

1.4.4 Desalination Section The desalination section includes a set of membrane elements, housed in pressure vessels which can be arranged in arrays. In a single-array system, two or more modules are arranged in parallel, while in multi-array systems two or more arrays are arranged in series. Feed, product and concentrate are connected to manifolds. A high pressure pump is used to feed the modules. Instrumentation, spare parts and tools for services are added as required. A cleaning-in-place (CIP) system facilitates the cleaning of the membranes. It may also be used as automatic flushing system to remove high salinity seawater from the system after shutdown and power failures. The desalination section is complete with an inlet feedwater and outlets for permeate and concentrate.

1.4.5 Post-Treatment Section Post-treatment should be chosen according to end-product use. In seawater desalination for drinking water production this is usually pH adjustment, rehardening and disinfection. Permeate contains a certain amount of of free carbon dioxide, which can reduce the pH of the permeate down to below 7.0 In the post-treatment system the free carbon dioxide is neutralised with hydrated lime or caustic soda, or it is filtered through dolomitic materials. A suitable means for disinfection are UV sterilizers. Additional chlorination may be required if the water is stored in a reservoir for an extended time period.

User Manual for Seawater Reverse Osmosis Plant SRO-250 1 GENERAL INFORMATION 1.5 Factors Influencing Reverse Osmosis Performance The permeate flux and the salt rejection are the key performance parameters of the RO process. They are mainly influenced by variable parameters which are as follows:

• Pressure • Temperature • Feed water salt concentration • Recovery The graphs below show the impact of each of those parameters when the other parameters are kept constant. They are intended to help the operator to adjust the plant performance to varying feedwater temperatures and salt concentrations. In practice, there is normally an overlap of two or more effects.

The arrows attached to the curves point to the corresponding axis of ordinate 1.5.1 Pressure With increasing effective feed pressure the permeate salinity will decrease while the permeate flux will increase as shown in Fig. 1.4.

1.5.2 Temperature If the temperature increases and all other parameters are kept constant, the permeate flux and the salt passage will increase (see Fig. 1.5)

SaltRejection

PermeateFlux

Pressure

SaltRejection

PermeateFlux

Temperature

Fig. 1.4. Performance vs. Pressure

Fig. 1.5. Performance vs. Temperature

User Manual for Seawater Reverse Osmosis Plant SRO-250 1 GENERAL INFORMATION 1.5.3 Feedwater Salt Concentration Fig. 1.6 shows the impact of the feedwater salt content on the permeate flux and the salt rejection. With increasing salt concentration the permeate flux will decrease and the salt passage will increase.

1.5.4 Recovery The recovery rate is ratio of permeate flow to feed flow. In case of increase of recovery the permeate flux will decrease and stop if the salt concentration reaches the value where the osmotic pressure of the concentrate is as high as the applied feed pressure. The salt rejection will drop with increasing recovery (see Fig. 1.7).

SaltRejection

PermeateFlux

Feed Concentration

SaltRejection

PermeateFlux

Recovery

Fig. 1.6. Performace vs. Feedwater Salt Concentration

Increasing

Permeate Flow

Salt Passage

Effective Pressure ↑ ↓Temperature ↑ ↑Feed Salt Concentration ↓ ↑Recovery ↓ ↑

increasing ↑ decreasing ↓ Table 1.1. Main factors influencing reverse osmosis performance.

Fig. 1.7. Performance vs. Recovery.

User Manual for Seawater Reverse Osmosis Plant SRO-250 2 GENERAL DESCRIPTION 2 System Description In the following sections, the components of the plant and their function will be explained. The abbreviations used in the text, e.g. KA1, refer to the flow diagram of the plant. Fittings, pipelines etc are only shown in individual cases. If there is a need, refer to the detail drawing in the Appendix. The following rule applies to operation, maintenance and repair of the plant and it is imperative that it be held to. If not, the guarantee is null and void. It is generally the case that membrane equipment is designed to operate in a continuous mode, as far as possible. Interruptions of longer than 48 hours are to be avoided. If such an interruption does occur, the equipment must be re-conserved following the shutdown and de-conserved before re-commissioning and starting up.

User Manual for Seawater Reverse Osmosis Plant SRO-250 2 GENERAL DESCRIPTION 2.1 Process Description

2.1.1 Feedwater Inlet

The inlet of the untreated seawater will be delivered by the external installed booster pump. The pump will be started from control board of the SRO. After start the water flows into the system through KA1 which will be opened after start automatically. The water must be at the specified inlet conditions. The inlet pressure is controlled by the pressure switch [PSA-1] which gives the possibility to check booster pump’s function and will occur a system shut down (alarm suppression adjustable; standard: 10 sec during normal operation). The volumetric flow of untreated water is measured and indicated by FQIS1, so the actual value is given to Profi bus and a pulse signal is used for counting. 2.1.2 Filtration (disc filter unit) The untreated water flows to filtration, splits in 4 equal streams which are fed to 4 disc filter systems each consisting 5 single filters. So 20 single filters are arranged in parallel. The water enters via incoming line, flows through the single filter vessel in radial direction and leaves the filter via effluent line. Two batteries each consisting of 10 single filters are arranged. Whole procedure (also backwashing – automatic started by PDIS1- measuring the existing pressure drop) is mentioned below in the special 3.1. Backwashing is possible by switching the arranged pneumatic valves. For control air preparing an air service unit is fitted in filter area (see chapter 10). 2.1.3 Dechlorination (NaHSO3 dosing) The filtered water flow then passes the line to the fine filter. Here is installed an injection point for dosing of NaHSO3. This was built in to be sure of preventing the destruction of the membranes by any free chlorine which might be present in the incoming water because of chlorination in ship’s system before. The dosing is designed for max. content of 2 mg/l Cl. The dosing pump is controlled by a Redox measurement QI1. The measurement will give alarm for new adjustment of pump in case the Redox potential is becoming out of desired range. The dosing unit is consisting of chemical vessel B2 and a dosing pump PD2 as well as the necessary valves, hoses etc. A low level switch LSA-2.1 is used to check the level of the chemical solution inside the vessel and to prevent pump’s dry running. Further pump’s operation is coupled to the open position of KA1 and minimal flow rate (adjustable) at FQIS1. For function of dosing unit see chapter 3.2 and 10. 2.1.4 RO-Membrane Protection (Dosing Scale Inhibitor) The next stage of the water treatment is the addition of a scale inhibitor to prevent scale deposits. The injection point is located after the Redox measurement. The dosing unit consists of the chemical vessel (B1) and a dosing pump (PD1) as well as the necessary valves, hoses etc. A low level switch [LSA-1.1] is used to check the level of the chemical solution inside the vessel and to prevent pump’s running empty. Further pump’s operation is coupled to the open position of KA1 and minimal flow rate (adjustable) at FQIS1. For function of dosing unit see chapter 3.2 and 10.

User Manual for Seawater Reverse Osmosis Plant SRO-250 2 GENERAL DESCRIPTION 2.1.4.1 Fine Filter (Cartridge Filter) The last stage of treatment of the inlet water is the fine filtration using a cartridge filter. The filter housing [F1] contains 7 pcs. of 40“ cartridges with fineness of 1 micron. The cartridges are there to remove the finely suspended particles which have managed to get past all the previous barriers. Two pressure gauges [PI3, PI4] allow the pressure drop across the filter to be measured and so to decide when the cartridges should be replaced. For filter instruction see chapter 3.4 and 10. 2.1.5 Reverse Osmosis System The water flow from the pretreatment stage is now led to the reverse osmosis system. The first step is to raise the pressure of the water to the necessary one by a high pressure pump. 2.1.5.1High Pressure Pump The high pressure pump [P3] is a multi stage centrifugal pump with a V-belt drive. Pump, motor and belts housing are all mounted on the main frame of the equipment. A safety valve [SV1] is fitted at the pressure side of the pump to prevent overloading the pipelines on the pressure side. On the suction side, the [PSA-2] prevents the pump running dry. The system is also shut down if the suction pressure drops < 2 bar. This ensures the necessary pressure rise and "catches" any failure in the untreated water supply. From the high pressure pump, the untreated water (which will now be referred to as feedwater) is fed to the feedwater inlet of the first membrane module. A pressure gauge [PI5] and a pressure switch [PSA+1] are mounted between the high pressure pump and the first module. The pressure gauge serves to monitor and adjust the operating pressure whereas the transmitter is an overpressure protection which operates at p > 70 bar for membranes protection. By hand valve [FH4] and [PI6] a raw pressure adjustment is possible when necessary.

2.1.5.2 Modules (Pressure Vessels and Membrane Elements) The 6 modules located on the wall side of the equipment are arranged as 2 x 3 in parallel. Each module consists of a pressure vessel and 3 reverse osmosis membrane elements (or permeators). The membrane elements are spiral-wound sea-water elements SW made from thin-film composite membranes that are particularly well suited to the desalination of sea water. In normal operation, the high pressure pump feeds the saline feedwater to the modules. Inside the modules, the feedwater splits into a product stream with extremely low salinity (permeate) and a concentrate stream with increasing salinity. The concentrate of the first element is the feed of the following element. The product headers of the 3 elements are joined by a so-called interconnector and connected to the permeate connector of the modules. The whole procedure is taking place in a 2 array manner. So the concentrate coming from the first one (3 pressure vessels in parallel) will be used as feed for the second array (also 3 pressure vessels in parallel).

User Manual for Seawater Reverse Osmosis Plant SRO-250 2 GENERAL DESCRIPTION 2.1.6 Clean Water System The permeate produced in the modules is collected in the permeate header outside the modules. Sample valves are fitted to take samples from single pressure vessel. The permeate flows to the conductivity measuring cell [QI2] of the salinity meter. The measured conductivity is the criterion for the product quality control. If the conductivity lies above the limit setting, an alarm is given. As conductivity is temperature-dependent, the signal is temperature compensated. The reference temperature for the compensation of the conductivity is 25 °C. After that the permeate passes the flowmeter FQIS2. This is installed for monitoring systems production and for controlling the regulation valve VR1. The regulation of this needle valve where the pressure relieve is taking place is organised so, that the permeate production will be constant. This is important for changing feed temperatures in different regions. Additionally FQIS2 gives the signal for creating the dosing pulse for NaOCl dosing unit [B4+PD4] for disinfection before permeate is leaving the unit. After that a pressure switch PSA+2 is installed. The purpose of this pressure switch is protection against too high permeate back pressure which can, for example, cause a backflow. High back pressures lead to membrane damage as these cannot tolerate reverse flows. The pressure on the concentrate side must therefore always be above that on the permeate side. This is always the case when the plant is in operation – this can, however, change when the plant is stopped. This is where the installed non return valve comes into play. In the permeate line are also installed two motor valves [MV3,MV4]. During normal operation MV4 is open, MV2 is closed. Permeate will leave the plant. MV2 will be opened (MV3 is closed then) after system’s start only for filling up the rinsing tank B3 with permeate at first. This is necessary for system’s flushing when unit will be stopped the next time.

2.1.7 Brine System (Concentrate) The concentrate of the first element is the feed water of the second and, so on. The fluid held back becomes more and more concentrated until it leaves the last element. The pressure loss across the two modules can be determined from the two pressure gauges PI6 and PI7. With the start of the high pump, depending on adjustment of VR1, the pressure is built up and the permeate production begins. The concentrate flows through the needle valve VR1, which is used to adjust the necessary pressure for desired permeate production at given feed temperature. So VR1, the concentrate flow control valve, controls the volumetric ratio of concentrate to permeate flow. The operating pressure, i.e. the feed water pressure generated by the high pressure pump, is displayed by the pressure gauge PI7. After VR1 the pressure will be at atmospheric range. For preventing high pressure in the line pressure switch PSA+3 is installed which causes a system shut down too. By reading flow meter FI1 the concentrate flow rate is shown and so the recovery rate can be computed. 2.1.7.1 Flushing Tank [B3]

In case of chemical cleaning the concentrate flow can be diverted into the vessel of the flushing and cleaning system (volume 1500l) via a branch pipe. The diversion is made opening the hand valves FH5, KH4 and PV2 after closing FH7. This allows a circulating flow over the modules during chemical cleaning of the plant.

User Manual for Seawater Reverse Osmosis Plant SRO-250 2 GENERAL DESCRIPTION 2.1.8 Flushing and Circulation Cleaning System

After the sensor of the conductivity measurement QI1, there is a branch line from the main permeate pipe to the flushing and circuit cleaning system. This is used to displace concentrate when the plant is shut down and in cleaning/maintaining the membranes. The inlet is controlled by the motorised valve VM3. After each start of the plant, the valve VM3 is opened so that the first permeate charge is used to fill the vessel B3. When the level of the switch LS+3.1 is reached, the valve VM3 is closed and VM4 will be opened so that the outflow of permeate from the plant begins. After each stop in plant operation, the permeate in B3 is used to discharge the concentrate on membranes surface. With the start of the concentrate discharge, the motorised valve KA1 in the untreated water line closes. The pump P3 starts to feed permeate from B3 into the untreated water line. The permeate flows over the cartridge filter and the high pressure pump to the modules. Apart from displacing the concentrate, the flushing and cleaning system also is used to maintain the membranes. An aqueous cleaning solution can be put into the vessel B3 and be used to clean the membranes. The pump runs till LS-3.1 is reached. The discharge pressure can be read from PI8. Also for preparing the chemical solution the pump is useful. By closing PV2 and opening KH5 an internal circuit for mixing can be organised. Additionally a temperature alarm TSA+1 is installed. During cleaning circuit the temperature will raise. Max. acceptable temperature is 40°C. When the value is reached an alarm will be given and the cleaning has to be finished (or make a break) or new solution has to be used.

User Manual for Seawater Reverse Osmosis Plant SRO-250 2 GENERAL DESCRIPTION

2.2 Technical Data (see also PID Schematic, Drawing No. 700062_MZ ) Unit Design data Untreated water volumetric flow l/h 35000 at p= 5 bar Flushing water volumetric flow (untreated water)

l/h 43000 at p= 5 bar

Permeate production l/h 10420 Max. salt content in permeate µS/cm 500 Recovery rate % 35 Design temperature °C 25 Operating pressure bar approx. 56 (at T= 25°C) pH value [-] approx. 6.0 (without post treatment) Untreated water specification raw water temperature range °C 2-40 °C

raw water feed pressure at inlet bar 5 raw water salinity ppm 36.000 Dissolved solids/TDS max. ppm 36.500 Blocking index SDI, max. [-] 5 Free chlorine, max. ppm 0,1 pH value - Normal operation [-] 2-11 - For short periods [up to 30 min] [-] 1-12 Dimensions Length mm common length (pretreatment +

osmosis) 11.000 mm Width mm 2000 Height mm 2200 Connections Untreated water inlet [-] DN 80 Concentrate outlet [-] DN 80 waste water discharge [-] DN 80/50 (filter) Permeate outlet [-] DN 50 Air for pneumatic control [-] G 3/4” Weight Operational weight kg approx. 8400 Power supply Supply voltage/frequency V/Hz 3 x 450 / 60 Power (general) kW App. 105 Main supply [-] 3 Phase/PEN

Table 2.1. Technical Data

User Manual for Seawater Reverse Osmosis Plant SRO-250 3 DESCRIPTION OF MAIN COMPONENTS 3 Function of the main components 3.1 Disc Filter

The documentation for the individual components should also be read in combination with this description. A disc filter installation of 4 x IF2/5/010/PP is used to treat the water before it goes to the reverse osmosis. The filter installation consists of four lines disc filters with 4 x 5 single battery elements. Fineness is carried out with 10 µm. Elements are made from PP with internal backflushing. The rated performance is 42 m³/h (parallel operation of the filters). The necessary operating inlet pressure is approx. 5 bar. The first filtration takes place over special formed discs. Seawater that has been cleaned by passing through the single filter vessels is used for back flushing another one. Backflushing is started when single pressure drop of 0.5 bar in PDS1 is reached (adjustable) and operates automatically. All elements will be flushed step by step now. Additionally an adjustable time for starting of backflushing is implemented (changeable). Also a max. number of rinsing cycles per hour (standard adjustment – 3 - changeable) is seted for sending an alarm because of bad feed conditions. The upstream pressure at the inlet is monitored via PSA-1. If the pressure drops below the seted value, the complete plant is shut down. The alarm is suppressed for 30 s during start procedure and 10 s during normal operation to prevent a false signal. This values are adjustable via OP7.

Note: - The plant is purely for use in filtering sea water. The supplier is not liable for damage caused by inappropriate use. - Chemicals are not necessary to run the plant. To prevent bacterial growth, a conservation of the plant is recommended if it will be stored for longer times. - Re-commissioning of the plant is done according to the special chapter 10/7.

3.1.1 Technical Data

Type: IF2/5/010/PP Manufacturer: Arkal No. Of filters: 4 pcs. Filter rate: 35 m³/h Maximum capacity: 43 m³/h (parallel operation) Operating temperature: 2-40° C Operating gauge pressure: 4 - 6 bar Permitted press. difference: 0,5 bar Pipe size, inlet : DN 80 PVC Valves: pneumatic Filter ∅ : 160 mm Cylindrical height of housing: 410 mm Backflushing water flow: 43 m³/h Necessary flushing water pressure: 5,0 bar Start of backflushing: automatic; initiated by PDS 1 Flushing water run off: free of back pressure, with gradient

User Manual for Seawater Reverse Osmosis Plant SRO-250 3 DESCRIPTION OF MAIN COMPONENTS

3.1.2 Operating the Filter Equipment

A rough filtration of solids to bring 35 m³/h seawater to service water is the preparatory stage for the RO plant. The filter is ready equipped in the works. The water flows through the filter from out to the inside. During operation, the pressure difference increases from an initial value of about 0.1 bar to about 0.3 bar. The automatic backflushing than sets in (standard 0.5 bar). The pressure difference is measured for this purpose (PDS1). In addition, there is a timer integrated into the control system which allows a time-dependent backflushing (see documents on the timer setting). A counter for backflush cycles/time is also integrated to give an alarm in case of too often backflushing.

3.1.3 Backflushing the Filter Equipment

The backflushing takes place automatically at p= 0.5 bar in PDS1 (standard adjustment – adjustable). On-board control air supply is used for controlling the pneumatic valves. This air is fed from the installed control air maintenance unit. The control air is monitored by a pressure switch. The backflushing of the filters takes place during normal operation of the plant. The LED’s at solenoid valve plate for control air supply to the pneumatic valves monitors the process. For details see special chapter 10/7.

3.1.4 First Filling with Water

The filling takes place according to water entry from booster pump and the filter coming into operation. For quick deaeration of system it is helpful to start some cycles of backwashing by hand at the beginning. After that the deaerator near water entry will ensure the complete filling of the unit.

3.1.5 Maintenance

- For maintenance, observe the rules and recommendations for the individual components.

- The switch contact PDS1 should be checked once a month and adjusted if necessary.

- For longer periods of standing still the filter has to be drained completely. Should inside bacterial growth took place, it can be removed before new start by opening the single batteries and clean the discs in a warm water solution with Permaclean or adequate substance.

User Manual for Seawater Reverse Osmosis Plant SRO-250 3 DESCRIPTION OF MAIN COMPONENTS 3.2 Dechlorinator (NaHSO3 dosing unit) For this purpose a dosing unit (see special chapter 10/8) is installed. The unit

consists of chemical tank B2, dosing pump PD2 and Redox measuring instrument. Further for control valve position of KA1 and min. flow rate at FQIS1 is used.

For used chemical see the safety data sheet Na2S2O5. The adjustment of stroke length and pumps frequency is explained in special manual.

The dosing container is equipped with level indicator which occurs a message and pump’s stop.

3.2.1 Technical Data dosing equipment for dechlorination

Pump type (PD2): gamma/L Gala 1000 Manufacturer: Prominent Material: PPE Q max.: 0.8 l/h P max.: 10 bar P: 0.02 KW Dosing chemical: Na2S2O5 Purpose: dechlorination Water flow rate: 35 m³/h (for 30% recovery) Dosing quantity: 3 g/m³ (for 100% concentration) Dosing quantity Na2S2O5: 105 g/h Capacity of dosing pump (P=85%): 0.7 l/h Capacity of supply tank: 60l (with LSA-2.1 as dry run protection) Total dosing quantity: 9 kg/tank Content sufficient for: app. 85 h operation

Observe the instructions in the document for individual components. Note:

The operating of dosing pump is coupled to the min. feed flow at FQIS1. Redox potential measurement QI1 is used for defining are desired range. 2 limit values can be seted for defining it. In case the measured value becomes out an alarm will be given for new adjustment of pump. Additionally the operation is coupled with valve KA1 which will open after systems start by the PLC (programmable logic controller). The chemical can be dosed at 100% concentration. Only freshwater may be used for dilution. The dosing pump should be adjusted to give the dosing quantity specified in the instructions. The quantity given is for chlorine content of 2 mg/l max. If there are variations in water quality, the supplier should be consulted because of danger of damaging the membranes. The same is true for failure of dosing equipment or in case of insufficient dosing.

User Manual for Seawater Reverse Osmosis Plant SRO-250 3 DESCRIPTION OF MAIN COMPONENTS 3.3 Dosing Equipment for Scaling Inhibitor

The dosing of HD30 hinders the formation of scale on the membranes. The system consists of a supply tank, the dosing pump, dosing fittings and piping.

3.3.1 Technical data:

Pump type (PD1): gamma L/ gala 1000 Manufacturer: Prominent Material: PPE Q max.: 0.8 l/h P max.: 10 bar P : 0.02 KW Dosing chemical: HD 30

Purpose: Hinder scale formation Water flow rate: 35 m³/h (for 30 % recovery) Dosing quantity for concentrate (100%): 5-10 g/m³ Dosing quantity BF 1000: 245 g/h

Capacity of dosing pump (for P=85%): 0.7 l/h Capacity of supply tank: 60l (with LSA-1.1 as dry run protection)

Total dosing quantity HD 30 : 20 kg / tank Content sufficient for: app. 85 h operation

Observe the instructions in the documentation for the individual components.

Note: The operating of the dosing pump is controlled by flow meter FQIS1 (min. flow rate) and coupled to the valve KA1 by the PLC (programmable logic controller). The chemical can be dosed at 100% concentration. A dilution of up to 10% is possible to get into the dosing range of the pump. Only fresh water may be used for this. There is however a danger of bacterial growth with a dilute solution. Unused solution should therefore be replaced after 3 days at the latest. The dosing pump should be adjusted to give the dosing quantity specified in the instructions. The quantity given is for sea-water. If there are variations in water quality, the supplier should be consulted because of the danger of scaling in the modules. The same is true for the failure of the dosing equipment or in the case of insufficient dosing.


3.4 Fine Filter

This filter carries out a fine filtration after the disk filters and is made as cartridge filter, type 07PP40-F80-VV-HSS-BAS with 7 off 40“ cartridges with a pore size of 1 µm. The cartridges are contained in a PP pressure housing. The pressure difference is determined from PI3 and PI4. The cartridges should be replaced if the pressure difference exceeds 1 bar. In addition, the cartridges should be inspected every two weeks. If fouling is visible on the cartridges then these should be replaced, even if the pressure difference limit has not been reached. To do this, screw off the head of the filter. The filter should be vented once a week or as necessary via FV1.1.

Following a cartridge change the filter should be run-in for about 5 min. by opening the valve FH3 and draining off the water. For further details, see the documentation for the individual components.

3.5 High Pressure Pump

The production of the necessary system pressure is achieved using a booster module of multistage centrifugal pipe covered pump. Pump type: BME 17-19 Manufacturer: Grundfos Serial-No.: 681366 Power supply: 90 KW; 450 V , 60 Hz Motor: 3 phase 280 SMA, ABB Note: Observe carefully the instructions in the documentation for the individual components. The operating pressure necessary for the process in each case is described in chapter 10/8. To protect the pump against running dry, a pressure switch (PSA-2) is mounted on the suction side.

The shut-off pressure is set to 3.0 bar (at first adjustment but can be changed during commissioning) in the works. After an automatic shut-down of the system, it can be started again by pressing the reset button as soon as the water pressure (PI4) is in the working range. If the operating conditions, the water quality and the temperatures are constant and it is necessary to raise the system pressure for getting the same permeate production, a flushing of the modules or a new adjustment of the system should be carried out. If this does not help, you should consult the supplier.


3.6 RO Modules

The RO plant is fitted with spiral wound modules. The recovery rate of the reverse osmosis elements is, as already mentioned, determined by the following factors:

Operating pressure Feed water temperature Feed water salinity

Whilst the temperature and salinity are properties of the sea-water, the operating pressure is automatically adjusted using the pressure control valve (VR1).

For the system are installed: Pressure vessel: 6 pieces 8“ GRP pressure piping in series from the Phoenix company Membrane modules: 3 per pressure vessel, from the company DOW Membrane: SWHR-380 Installation: 3 pcs. 8” in parallel. Two batteries out of 3 pieces in line For further information see the membrane manufacturer’s documentation.

3.6.1 Adjustment of the RO System

Intended recovery: 30 % Permeate flow (indication: FQIS2): 10.4 m³/h Design temperature: 25° C Inlet flow of untreated water: 35 m³/h, p = 5 bar Concentrate rejection flow (indication: FI1) : 24.6 m³/h Ensure during the running of the plant that the permeate is not under pressure when fed to the storage tank. All external shut-off valves in the permeate and concentrate lines must be fully open in order to prevent back pressure (possibly also reverse flow) occurring in the modules (=destroying the membranes). As an additional safety measure, the permeate and concentrate sides are fitted with over-pressure protection (PSA+2, PSA+3), which give an alarm if p > 4 bar (first adjustment – changeable) and shut the plant down. Each line has a none-return valve to prevent backflow.

Attention: If the water temperature changes, a pressure compensation will take place at VR1. This will be achieved by regulating the flow rate at FQIS2 to a constant rate (10.4 m³/h). To prevent scaling on the membranes a minimal flow range is necessary. That’s why the regulation is limited to max. change of valve position. Apart from that, there are no changes to be made in the basic settings. Cleaning of the elements should be done when the permeate flow drops by 10% below the set level, the salinity of the permeate rises noticeably (FQIS2) or the pressure difference across the osmosis modules (PI6,PI7) or the inlet pressure rises by 15 % (for constant operating conditions). Flow rates and pressures during the first 48 hours of commissioning should be noted and entered in the operating log. The operating log should be filled out completely once a day when the RO plant is running (see Appendix).


3.7 Flushing and Cleaning System

The system consists of the flushing vessel B3 ( V = 1500l) with 1 level measurements (with 3 switching levels) for controlling the rinsing water pump P3. The system with its piping is fully integrated in the RO plant. With its help the following are carried out: 1. The membrane modules are flushed with permeate after each shutdown. 2. If needed, the chemical cleaning of the RO modules can be carried out. The flushing function under normal operation is shown in paras. 4.3.2 and 4.4. The cleaning of the RO modules is necessary when the pressure difference across the modules increases by more than 15 % or the pressure on the inlet side of the modules rises by more than 15% (but not when this is caused by temperature effects). The cause for this can lie in a fail operation (e.g. the dosing chemicals have run out or the dosing has been wrongly adjusted) or from fouling or scaling. For this reason, a regular preventive cleaning of the modules can be necessary – this shows itself in the first months of operation. We recommend initially an annual preventive cleaning. The cleaning must be done by the staff. Given sufficient notice, it can also be done by the supplier. The cleaning process is described generally in the section number 8. The correct procedure depends essentially on the type and degree of fouling and so cannot be set down as a universal rule. Citric acid and an alkaline cleaner are used mostly. The disinfection is done with peracetic acid (of a suitable quality). The steps in the cleaning have to be done as stipulated by the supplier. The chemicals are put together in the tank B3 and transported through the plant in a depressurised condition by the pump P3). The complete plant is shut down for this. There then follows the mixing of chemicals in vessel B3. Fresh water is necessary for this. To produce the cleaning solution the pump 3 is used in internal circuit by opening KH5 and closing PV2. The circuit should be operated for app. 5 min. After that close the valve and open PV2 (adjustment for pump’s pressure is possible here). MV3 and MV4 are closed. Before starting the procedure open the valves FH5 and close FH7. The flushing pump P3 is started up and pumps round a closed circuit. The high pressure pump remains shut down. The dosing equipment is not operational (high pressure pump is not running). After each step in the cleaning procedure, the flushing vessel should be emptied and the plant, not under pressure, thoroughly rinsed with untreated water. For this, first close FH5 and then open FH7. The pumps then are used to drain the used cleaning solution from the system. Then open the motorised valve KA1 and flush the plant with sea-water using the external feed system. After the flushing and the resetting of the valves as well as a new mixing of cleaning solution using permeate, the next cleaning step can be carried out. The cleaning circuit valves are closed again and the outlet valves opened. It is absolutely necessary that you keep to item 8 of the accompanying cleaning specification. Please read it. Conservation of the RO-Modules is necessary, if the SRO - Plant is shut off for a period longer than 48 hours. The conservation has to be done in accordance with the RWO - Service Department.


Rinsing Pump Data Allweiler Type : NI-H 40-160/01-W3 Capacity : 35 m³/h at p= 4.1 bar Power Consumption : 8.6 KW Please see the individual documentation as enclosure.

3.8 Chlorination dosing unit (NaOCl dosing unit) For this purpose a dosing unit (see special chapter 10/8) is installed. The unit

consists of chemical tank B4 and dosing pump PD4. Further for control valve position of KA1 and min. flow rate at FQIS1 is used.

For used chemical see the safety data sheet NaOCl. The adjustment of stroke length and pumps frequency is explained in special manual.

The dosing container is equipped with level indicator which occurs a message and pump’s stop.

3.8.1 Technical Data dosing equipment for chlorination

Pump type (PD2): gamma/L Gala 1601 Manufacturer: Prominent Material: PPE Q max.: 1.4 l/h P max.: 10 bar P: 0.02 KW Dosing chemical: NaOCl Purpose: chlorination permeate flow rate: 10.4 m³/h (for 30% recovery) Dosing quantity: 2 g/m³ (for 100% concentration) Dosing quantity Na2S2O5: 105 g/h Capacity of dosing pump (P=85%): 1.2 l/h Capacity of supply tank: 60l (with LSA-2.1 as dry run protection) Total dosing quantity: 1.6 kg/tank Content sufficient for: app. 50 h operation

Observe the instructions in the document for individual components. Note:

The operating of dosing pump is coupled to the min. feed flow at FQIS1. Additionally the operation is coupled with valve KA1 which will open after systems start by the PLC (programmable logic controller). The chemical can be dosed at as given above. Only freshwater may be used for dilution. The dosing pump should be adjusted to give the dosing quantity specified in the instructions. The quantity given is for chlorine content of 2 mg/l for storaging. In case of failure of dosing equipment or in case of insufficient dosing contact the deliverer.


3.9 EMSR Electronic Measuring and Control Equipment

The process of the SRO-Plant is controlled by the SIEMENS S 7 PLC (Programmable Logical Control). The control panel is equipped with all necessary switches, LED - indications and displays. The SRO-Plant might be operated

• manual • automatic at side • external from control room

All necessary automatic emergency stop requirements to project the SRO-Systems are implemented. Note: All electrical components of the control panel for the operation of the SRO - Plant and a short form of the start up procedure are indicated in the schedule OP7 (incl. foil for menue). The indication module of SRO-System OP7 is explained in the special schedule for it. In DB100 a list of important values for operation is memorised and can be given to IAMCS by Profi bus connection. Following parameters are available: 1 Booster pump P1 operation/fault 2 pmin. at PTA-1 achieved 3 discfilter via PDS1 max. number of backwashing cycles / time is reached 4 PD1 operation /fault-min. level 5 PD2 operation /fault-min. level 6 QI1 Redox potential analogue value 7 TSA+1 temperature exceeding max. value 8 pmin. at PTA-2 achieved 9 high pressure pump operation /fault 10 PTA+1 max. pressure exceeded 11 QI2 conductivity analogue value 12 FQIS2 flow analogue value 13 PTA+2 max. pressure exceeded 14 PTA+3 max. pressure exceeded 15 PD4 operation /fault-min level 16 level LS3.1- reached 17 level LS3.1++ reached 18 rinsing pump P3 operation/fault 19 control device voltage failure Also the implemented program is listed and given as floppy disk. The whole wiring is shown in E5527.

User Manual for Seawater Reverse Osmosis Plant SRO-250 4 SYSTEM OPERATION

4 System Operation Instructions 4.1 Safety Instructions 4.1.1 Noise

The continuous noise level of the reverse osmosis system - high pressure pump can reach 76 dB(A). Also at needle valve it is high. When working on the equipment, hearing protection should be worn.

4.1.2 Sources of Danger

Danger

Voltages > 41 V Direct contact leads to injury. Set the main switch to position 0 before working on the electrical parts of the system or the consumers. Warning All pumps have moving parts. The cover for this should never be removed when the motor is running. If it has to be removed for maintenance or other purposes, it should be replaced without delay as soon the work is finished. Warning Pressure vessels and pipelines are sources of danger. These should be depressurised before working on the system.

4.2 Commissioning and Start-up

Note: All designations in the description refer to the given PID in the Appendix.

4.2.1 Requirements a) Power supply to the system is established. Danger Voltage > 41V Direct contact can lead to injury The power in-feed must be established by qualified personnel Danger Explosion hazard! The system may not be operated in an Ex-area b) Pipe connections for feed water inlet, permeate and concentrate outlet as well as drains are made and are water-tight. All interconnecting pipes are well fitted and tight.


Danger Pressure vessels and lines are sources of danger. These should be depressurised first before working on the system. c) All wiring between both containers is carried out in acc. to the given diagrams. This has to be done in well manner acc. to VDE rules by skilled staff. d) The raw water entry is connected to platform’s pump system. Warning All pipes and especially the discfilter section is constructed for pmax.= 10 bar. A pressure safety device should be installed in upstream system. e) The feed water available meets the required inlet conditions, i.e. it contains no substances which are atypical for sea-water, it is oil-free, the feed temperature is inside the given range. The chlorine concentration at inlet is max. 2 mg/l.

f) The dosing systems are filled in acc. to given information (see chapter 3). Dosing pumps are checked for function and adjusted to 50% capacity. g) All pumps are checked for function and rotating direction. h) The external permeate tank is empty.

i) The coupling of the system control to the level switch of the permeate storage tank is made.

j) connection from ship’s control air system to control air maintenance device at solenoid valve at solenoid valve plate for pneumatic valves in discfilter area is made and tight.

4.2.2 Requirements before Start-up 4.2.2.1 General Information The system is delivered in a conserved state.

this means that the spiral wound module for reverse osmosis and its piping system have been protected by a conservation solution against bacterial fouling. Before the permeate can be consumed, it is therefore necessary to carry out a de-conservation.

4.2.2.2 Removal of Conservation

1- All external valves in the feed water, concentrate and waste water lines should be open and the external valve in the line to the permeate storage tank closed.

2- The unit don’t need to be started. For flushing out the chemicals it is only necessary to use the booster pump. The following has to be carried out:

open the following valves: PV1,KH2, KH3,FV1.1 FH4,VR1, FH7 At least open KH1 and let in seawater to the system with booster pump’s

pressure of 5 bar. Hold on for app. 15 minutes. After that stop the pump and close KH1. Now the

system is free of conservation chemicals. 4.3 Manual Start-up


The system must be started by hand following a de-conservation, a long period out of service (> 48h) and after an emergency shutdown. This is not necessary in normal operation but of course possible.

4.3.1 Requirements All elements are in the positions as at the end of 4.2.2.2 .

All dosing equipment has been filled. 4.3.2 Execution

Before switching on all hand valves in permeate and concentrate line should be opened, but the following must be closed:

KH1, FV1.1 (use only for deaeration), and FH5. Raw water with right pressure is available at KA1 by booster pump. Control air is available too. Further the following is to do: 1-2Q1, 2Q2, 2Q3, 2Q4 to position I -switch board lamps and current meters are in operation; 230 V control voltage and 24 V DC are available 2-2S1 to position I -voltage measuring in operation -measuring instruments installed in piping and switch board are in operation 3- 4S0 to Auto (for operation of single parts only switch to Man.) 4-4S1 motorvalve raw water to auto 5-5S1 dosing antiscale to auto 6-6S1 dosing NaHSO3 (dechlorination) to auto in case the raw water chlorination in upstream is in operation 7-8S1 high pressure pump to auto 8-10S1 rinsing pump to auto 9- 11S1 pressure regulating motorvalve in concentrate line VR1 to auto 10-11S2 filling motorvalve MV3 to auto 11-11S3 permeate motorvalve MV4 to auto 12-11S3 motorvalve permeate to auto (MV3) 13-13S1 dosing NaOCl to auto 14-3S1 to position start (for control voltage on; light, heating and venting are available too) Operation of the unit will be made by using menue of OP7 (password supervisor: 100) For lamps indication at switch board use the labels below the lamps. After start delay the unit starts with opening KA1 and filling the unit. Then dosing and high pressure pumps starting operation. Value for Redox potential is monitored at 7N1 and will occur pulse for operation of dechlorination dosing. Also conductivity at 12N1 is monitored and an alarm in case of exceeding the adjusted limit will be also created (incl. in common alarm). Further the measuring values from FQIS1 are monitored at 3P1 and from FQIS2 at 12P1. Monitors creating signals to the SPS for connection to the IAMCS.


FQIS2 is delivering the permeate flow rate also for regulation of VR1. This will be done continuously in following manner: A flow range is defined by setting a max. value for flow max. and computing a min. one by subtraction of adjustable value from seted max. one. 1. Flow exceeds max. limit – VR1 will be opened (max. fully open) until the

measured one at FQIS2 is in range again. 2. Flow achieved computed min. value - VR1 will be closed until the measured one

at FQIS2 is in range again or the max. value for valve position changing is reached.

So the system pressure increases/decreases at PI7 by regulation of needle valve position VR1 coming from SPS via FQIS2. This procedure will be arranged so, that the permeate stream at FQIS2 should be constant at 10.4 m³/h. The adjustment is limited to a max. changing by end position switch at the valve to ensure minimal flow rate at concentration side of membranes (preventing of scaling). The pressure at PI5 is depending of raw water temperature and salinity content in raw water. For extreme conditions (required with 2°C) it may reach max. 70 bar. Warning Max. pressure adjustment of the system can be max. 70 bar at PSA+1 because further increasing will destroy the membranes. First produced permeate (app. first hour) after first start should be given back to the sea. After that extern permeate tank can be filled by opening the external tank valve. During operation all process data are available direct at installed instruments and so far as implemented at OP7. For handling of OP7 follow the instruction foil with main and submenue.

Note 1 The permeate production of the system is temperature-dependent as already explained. The

design was carried out for a feed temperature of 25°C. In case of deviation from this value to higher ones the permeate production and residual salinity in permeate will raise.

So the regulation will occur a readjustment of VR1 to lower pressure value. Because of that the permeate production will be lower (aim is to ensure the same 10.4 m³/h as the unit is made for.) So the monitored pressures at PI5,PI6 and PI7 will be lower. Should the conductivity of the permeate exceed the limit setting of 600 µS/cm (corresponding salinity 420 mg/l) with 3 min delay (first adjustment) an alarm will be signalised; the value can be read off on 12N1. The unit will continue the production. The permeate flows at first through the open motorised valveVM3 to the rinsing water tank B3. When the tank is full ( LS+3.1 is achieved) VM2 closes and VM3 will be opened. The permeate flows to the external permeate line. (- in case of pressure level > 3 bar at PSA+2 and/or for PSA+3 in permeate or concentrate line the system will shut down because of overpressure alarm). All situations can be red at OP7.

Note 2


To eliminate scaling on the membranes, an inhibitor HD 30 is injected into the line following the discfilter. The dosing is in operation when min. flow at FQIS1 is given and the valve KA1 is open.

For setting the dosing pump see para. 3.3. Note 3 For chlorination after treatment chlorine granulat solution will be injected into the permeate

line before water will leave the unit. The dosing is in operation when min. flow at FQIS1 is given and the valve KA1 is open.

For setting the dosing pump see para. 3.3.

4.4 Shut Off

- the system is automatically shutdown if any of the following limit settings PSA-1, PSA-2, PSA+1, and/or PSA+3 are exceeded. The settings made in the factory are as follows:

PSA-1 PDS1 PSA-2 PSA+1 PSA+2 PSA+3 5 bar 0.5 bar 3 bar 70 bar 3 bar 3 bar

PDS1 will occur a backflushing of discfilter unit. Backflushing is taking place filtermodule by filtermodule. So there isn’t necessary a production brake for that.

- In normal operation stop the unit by using external signal or by OP7 menue. - High pressure pump stops. - KA1 will close. - Dosing pumps will stop. - Pump P3 starts and flushes the RO system via fine filter with first permeate out of tank

B3 as long as low level LS-3.1 is reached. - the flushing discharges via the concentrate line and displaces the concentrate in the

RO modules. This reduces the osmotic pressure on the membranes. It also restricts the fouling in the modules.

- the system can be stooped for 24h without taking any particular precautions against fouling

- if the system is taken out of service for more than 48h, then the following should be done: a) Prevent drying out of the membranes (drying out means destruction of the

membranes) b) The system should be conserved against biological fouling or brought into service

once every 24h.

4.5 Automatic Start-up

This function is given, by using the external contact from permeate tank at X4 44/45. So after start the unit is running continuously until it will be stopped because of external level switch in tank.

User Manual for Seawater Reverse Osmosis Plant SRO-250 5 Measuring and Control Equipment 5 Measuring and Control Equipment

This section describes the construction of the operating panel, the function of the operating

and alarm displays and the wiring of the control cubicle. Take note of the foil for OP7 with it’s menue for starting and operation during normal service. Note: The control program together with its parameters for the complete system which lies in the

PLC (programmable logic controller) has been burned on to an EPROM and is so protected against erasure. A print-out of the control program is included in this chapter. Also a floppy disc. Parameter changes should only be made in agreement with the supplier. If not, the guarantee is null and void.

User Manual for Seawater Reverse Osmosis Plant SRO-250 6 MAINTENANCE 6 Maintenance

Each piece of equipment should be maintained as laid down in its own set of maintenance instructions. Reading this set of user instructions is no substitute for the studying of the individual operating instructions and specifications. The added operating log should be filled out completely to make it easier to understand the cause of any faults and failures. One can also see whether there were any signs of an prior to the actual occurrence of the failure. The guarantee is null and void in all points when all the columns have not been completed or the maintenance work has not been carried out according to the manufacturer's specifications. During the agreed warranty period, the system must be maintained two times per year by the supplier.

Should it be necessary to replace membrane modules, then the supplier should be contacted.

We therefore recommend, for the above reasons, that the customer take out a maintenance contract with the supplier. 6.1 Membrane Elements

The elements of type FILMTEC SWHR-380 must always be treated such that the growth of algae and bacteria is avoided and the membrane performance is not negatively affected by period in store or longer periods out of service. Only shortly before they are to be installed, the elements should therefore be taken out of their packing. Otherwise there is a danger of their drying out.

6.1.1 Conservation Warning: You must follow the recognised safety instructions and currently valid regulations when handling biozides which are used for conservation. Always wear protective goggles.

New elements are transported in a conservation solution of 1 % sodium bisulphate and 20 % propylene glycol. Bisulphate works as a biozide, whilst the propylene glycol protects against frost damage. Each used membrane element, which has been taken out of the pressure vessel and stored, must be appropriately conserved. This is as a rule not necessary (as the removal is usually only done when an element is damaged) and should only be done when absolutely necessary. Use a one percent sodium bisulphate solution (weight percent; food quality, without cobalt). Glycol is only necessary when there is danger of frost. Steep the element for an hour in the solution, and wait till the liquid has properly drained off. Then pack the element in an oxygen-proof plastic cover as the bisulphate deteriorates in the presence of oxygen. We recommend you to use the original packing again. Do not fill the plastic cover with conservation solution- the moisture content in the element is sufficient for conservation purposes. Apart from sodium bisulphate other approved biozides can be used. Should formaldehyde be employed, then the membranes must have been at least 6 hours in service before permeate is useful again.

User Manual for Seawater Reverse Osmosis Plant SRO-250 6 MAINTENANCE 6.1.2 Reconservation

Warning Note that the membranes where conserved when the units left the factory because of preventing any fouling. This solution has to be replaced every 6 months because of becoming weak. So follow up the instructions given below or order service by manufacturer. If the new conservation during long time storage won’t be carried out in regular intervals out guaranty for well function is null and void. As conservation fluid use the same as described in 6.1.1. Necessary volume will be 665 l. So fill up the rinsing tank with 665 l and add chemicals for double volume that means for 1330 l (in case the unit is filled with water from normal operation). For chemical concentration see the safety data sheet.

For procedure the system is stopped and you proceed as follows: 1- The rinsing water tank B3 is opened and used for the mixing of the conservation solution. Use clean water and stir well to get a consistent solution The chemical dosing should be measured out to suit the tank with a solution of clean freshwater with chemicals. Drain the pressure vessels by opening VR1 and FH7 from old conservation solution (or flush it out in acc. to procedure 4.2.2.2 if possible 2- All switches should be in position 0. 3- Switch on 2Q1, 2Q2, 2Q3, 2Q4 4- VR1 has to be fully open (manually or by adjusting the desired permeate flow at FQIS2 in program to 0) 5- Close MV3 and MV4 6- Close PV2, FH2 and FH7 open KH5 7- Start the rinsing pump P3 manually by switching 10S1 to MAN

let the pump operate in inner cycle for 15 minutes for mixing the chemicals with fresh water

8- Following valves have to be opened: KH2, KH3, FH4 and FH5 9- Close KH5 and open PV2 Let the rinsing pump operate in rinsing circuit for min. 30 min. 10- Stop all machines and close all valves; bring back into service as in para. 4.2.2.2

User Manual for Seawater Reverse Osmosis Plant SRO-250 6 MAINTENANCE 6.1.3 Exchange of the Module If it is necessary to replace a module, the system should be taken out of service and

the modules emptied (sample drain cocks). The connecting high pressure and permeate pipes should be loosened at the

pressure lines on the modules. The end plates on the modules should be removed (socket-head screws). The membrane modules should be first pushed out of the pressure vessels in the flow

direction by means of a suitable tube/plunger, and then pulled out. The adapters which connect the modules should be loosened. Doing this makes it

possible to work with the modules singly. The adapter can be used again. Their seals (O ring) should be inspected and replaced, if necessary.

The new modules should be pushed in the direction of flow (seal side is the inlet side of the water flow!) and connect each by means of the adapter which lies upstream of it. Should it be difficult to push in a module, lubricate the seal with soap or something similar.

Once the installation of the modules is complete, fit the endplates to the pressure vessels again and connect up the pipelines (do not use Teflon!).

The system is now deconserved (as in 4.2.2.2/3) and brought back into operation in (as in 4.2).

6.1.4 Sampling

The sampling drain cocks at the permeate lines near front plates of pressure vessels allow the taking of samples at the relevant points (see diagram). This allows an insight into the operating state of the single system parts.

6.2 Operations log The accompanying form contains all important parameters in the system. It is to be

filled out daily so as to recognise faults and to be able to assess their influence.

User Manual for Seawater Reverse Osmosis Plant SRO-250 7 TROUBLE SHOOTING 7 Disturbance, Fault Analysis and Repair Hints No. Trouble Reason Remedy

1 High pressure difference between inlet and outlet of the modules, respectively pressure rise 15 percent or more(PI6-PI7).

Fouling on the membrane surface, clogging

Cleaning procedure of the modules

2 SRO shut down, because of the pressure switch PDIS 1- to many backwash cycles per time

Disc filter clogged Filter backwashing in acc. to special chapter Check the raw water Open the discfilter modules and clean it (see special chapter

3 Rise of the working pressure of more than 15 percent at constant water temperature because of regulation at VR1

Change of the salinity Check the raw water

4 High pressure difference between inlet and outlet of the fine filter

Filtercandles are clogged Exchange of filter candles. See separate instruction Check discfilter effluent

5 flow rate at FQIS2 becomes lower what means min. concentrate flow is achieved by regulation of VR1 to max. pressure

Conductivity to high, module defect Conductivity in normal range, feed temperature too low

Check each module by taking samples at sample cocks and analysis of the samples. If necessary, clean or exchange the modules

6 Permeate flow to high. Pressure after the modules to low

Module defect. Leakage at the module gaskets

Check the modules and gaskets. Check the salinity of the permeate of each module to identify the leakage

7 Shut of, because of dry running (PSA-2 to low)

Fine filter clogged Exchange filter candles. Check the function of the multi layer filter and the activated carbon filter

8 Shut off because of switching at PTA-1

Feedwater pressure to low. Pressure changes in the feed water pipe system.

Rise feed water pressure. Adjust the pressure switch, but not lower than 3 bar. Check the booster pump and pipe system

9 Alarm because of reaching Limit value at TSA+1

High feed temperature Too long circulating during Chemical cleaning

Units operation not possible because of environment Make a break or change the cleaning solution

User Manual for Seawater Reverse Osmosis Plant SRO-250 7 TROUBLE SHOOTING No. Trouble Reason Remedy

10 Conductivity limit value QI2 to high. Permeat quantity o.k.

Limit value too low. Wrong value adjusted

Readjust the limit value

10 Conductivity at QI2 to high RO-module defect Check each RO-module and exchange, if necessary

11 Conductivity at QI2 to high O-ring defect Exchange O-ring

12 Dosing pump fault message or systems shut down because of that

Dosing pump defect dosing tank empty

Check chemicals level Check monitored dosing pump (see special chapter)

13 Systems shut down because of any pumps failure

Pump defect or wiring problem Check described pump (see special chapter)

14 Systems shut down because of high pressure at PSA+2 or PSA+3

Piping down stream clogged Check piping and valve adjustment in permeate/concentrate line

15 Systems shut down because of high pressure at PSA+1

Wrong pressure regulation at VR1 because one membrane is clogged

Readjust the system Flush the system

16 Alarm because of high Redox potential at QI1

Chlorine content in raw water too high Measuring defect Dosing NaHSO3 defect

Check NaHSO3 dosing Check the raw water Check measuring/monitoring device (see special chapter)

Use the signalisation at OP7 for any failure.

User Manual for Seawater Reverse Osmosis Plant SRO-250 8 GENERAL CLEANING INSTRUCTION

8 General Cleaning Instructions

Listed below are the most important points concerning:

Method for cleaning the RO modules Chemicals used for cleaning Cleaning procedure

(see also the following pages) - please take note!

The method and the extent of the cleaning depends essentially on the degree and type of fouling. As this, however, cannot be determined in most cases before the cleaning, it is necessary to lay down a generally valid procedure. The membrane elements can suffer in their permeate production rate and/or their ability to hold back the salt. For this reason, cleaning should be carried out when, at constant operating conditions, the system loses more than 10% permeate production, the salt content of the permeate rises by > 5% or the pressure difference between PI6 – PI7 rises by > 15% compared with the value in the first 48h of service. The accompanying detailed cleaning specification shows the exact procedure for a comprehensive acidic and alkaline cleaning, followed by a final disinfection. An acid cleaning for the removal of mineral scale is best carried out at a pH value of <= 2 using citric or other acid (not sulphuric acid because of sulphate deposits). The alkaline cleaning for the removal of biological scaling is generally done using NaOH. The pH value should be around 12. Various combination products (such as EDTA) are possible. Generally speaking, anionic substances can be used for the alkaline cleaning. Cationic substances cause an irreversible reduction in the flux and may not be used. The cleaning solution should have an initial temperature of at least 15°C, as the rate of cleaning drops considerably at lower temperatures. After the cleaning, a thorough rinsing with chlorine-free clean water should be carried out (minimum temperature 20°C). This rinsing should take place at first at reduced pressure (i.e. higher concentrate flow). After that the working pressure can be restored. The duration of the re-start must be at least 15 minutes. The times mentioned are only approximate values. The cleaning process can generally be ended when, at operating pressure, the conductivity at QI2 again lies in the normal range – which usually means after one hour. Care must be taken here that the temperature of the cleaning medium doe not rise above 40°C what will occur a shut down by TSA+1. A temperature rise always take place in the circulating fluid because of the mechanical work performed by the pump. The filters should be separated from the circulating flow - close valve FH2. Proceed for the SRO modules as for reconservation and deconservation (part 6.1.2/4.2.2).


Short Summary of Procedures: The cleaning consists of 6 stages: 1. Mixing of the cleaning solution 2. Pumping of the cleaning solution in a circulating flow at low pressure No permeate is produced, there is only flow on the concentrate side A dilution of the solution by water present in the system is to be avoided, i.e. it should first be drained off. 3. Pumping of the circulating solution for 30 minutes - 1 hour 4. Saturation; approx. 4 h interval to saturate the elements with the solution; no pumping 5. Pumping of the circulating solution for 30 minutes - 1 hour 6. Rinsing Note: The pH value should be checked during the acid cleaning because it will raise as the acid gets used up when dissolving the scale. Acid should be added if the pH value becomes > 0.5. Concrete steps to take: 1.) Make a log of performance data ! (i.e. system runs at operating pressure) 2.) Acid cleaning: A 2% citric acid solution is used in most cases for the acid cleaning. This gives a low pH value in the mixture. The temperature should not exceed 35°C. The dosing equipment is not in service. One can roughly set the system content as equal to the content of the empty pressure vessels. Calculation of mixing quantity (example): Vol. flushing vessel: approx. 300 l Vol. press. vessel (empty): 100 l Total volume: approx. 400 l Mixture: 2 % = 8 kg. Put citric acid in the full flushing vessel, mix well and stir, so that the acid is evenly distributed. Then proceed as described here. End the cleaning when the cleaning medium has become very dirty. Attention: Use a high circulation velocity, however, the pressure difference over the modules should if possible not exceed 2 bar (PI6, PI7). Flow in the normal case 5 m³/h per 8“ RO pressure vessel; for a 2 in 1 or other pressure vessel construction, the flow in the last pressure vessel may not exceed 10 m³/h. The flow rate can be determined from the flushing pump's head/flow characteristic (use PI8) and adjust the capacity by PV2. 3.) Water rinsing:


It is important that sufficient rinsing of the system with clean water takes place. For this, use clean water (if not possible, then feed water). the dosing equipment is not in service. The system is rinsed at low pressure. A flow of 5 m³/h per 8“ pressure vessel should not be exceeded. The pressure is then raised to the operating value (VR1) and the success of the cleaning checked at the conductivity measurement QI2. 4.) Log the performance figures ! (i.e. system runs at operating pressure) 5.) If conductivity too high, repeat the acid cleaning. 6.) Water rinse: (see item 3) 7.) Log the performance figures ! (i.e. system runs at operating pressure) 8.) Alkaline cleaning: Various cleaning media can be used for an alkaline cleaning, e.g. Ultraperm 10. According to the latest knowledge, Ultraperm 11 should no longer be used. Caution: do not exceed a temperature of 25°C during the cleaning, the pH value should not be above 12 after mixing; use some citric acid to bring it down, if necessary. Ultraperm should be used in a 0.5 % concentration. Calculation of the mixing quantity as described. For example, 0.5 % of 400 l = 2 kg Ultraperm, so that the cleaning medium is distributed evenly in the system. Then proceed as described here. End the cleaning when the conductivity is again in the normal range (after about 1 hour). The maximum temperature of 40°C may not be exceeded. Set the circulating flow rate as described in item 2. 9.) Water rinse: (see item 3 ) 10.) 10.) Log the performance figures ! (i.e. system runs at operating pressure) 11.) If the conductivity is too high, repeat the alkaline cleaning. 12.) Water rinse: (see item 3 ) 13.) Log the performance figures ! (i.e. system runs at operating pressure) 14.) Disinfect in the case of biological fouling For this, conserve the system for 1 hour with a sodium bisulphite (as in 4.2.2.2/3) (a strong acid/alkali solution is also possible) and rinse ( see item 3) 15.) Water rinse: (see item 3 ) 16.) Log the performance figures ! (i.e. system runs at operating pressure)

User Manual for Seawater Reverse Osmosis Plant SRO-250 Function Check

Function check of the RO-System Important Data:

Pressure of High Pressure Pump at PI5 Pressure at the Inlet of the Modules at PI6 Pressure at the Outlet of the Modules at PI7 Permeat Flow Rate at FQIS2 Concentrate Flow Rate at FI1 Feedwater Conductivity (Salinity) platform’s measuring Permeat Conductivity (Salinity) at QI2 Feed Water Temperature ship’s measuring Feedwater Redox potential at QI1

Procedure 1. Completion Protocol Data Sheet 2. Low pH Cleaning 3. Water Flushing 4. Completion Protocol Data Sheet 5. If necessary repeat low pH-cleaning 6. Water Flushing 7. Completion Protocol Data Sheet 8. High pH-cleaning (alkali) 9. Water Flushing 10. Completion Protocol Data Sheet 11. If necessary repeat high pH-cleaning 12. Water Flushing 13. Completion Protocol Data Sheet 14. Desinfection 15. Water Flushing 16. Completion Protocol Data Sheet After each cleaning take a 100 ml sample for testing

User Manual for Seawater Reverse Osmosis Plant SRO-250 9 SPECIAL TERMS 9 Glossary of Terms in Water Treatment Array Series of parallel installed pressure vessels with common feed,

product and reject lines. Backwash Reversed flow to remove foreign material from a filter bed and

reduce its compaction. Bank One of two or more complete reverse osmosis installations

operating in parallel. BOD Biochemical Oxygen Demand. The BOD is the amount of

oxygen absorbed by a sample of water. Boundary Layer Layer adhering to the membrane facing the feed water, having a

higher solute concentration Brackish Water Naturally occurring saline water, containing more than 1000 ppm

and usually less than 15000 ppm TDS (other values 1500 - 6000 ppm)

Brine Any flow associated with the process with a salinity higher than that of the feed flow (see concentrate).

Channelling Unevenly distributed flow as may occur in elements or filter beds.

Chlorinating Application of chlorine, Hypochloride, etc. in order to avoid bacterial growth in the product water.

Chloride Affects the potability of water and can be extremely corrosive as its molecular size is such that it can penetrate protective oxide-metal interfaces and react with steel structures.

CIP Cleaning-in-place Coagulation Pre-treatment process involving the formation of flocs from

colloidal suspended matter, thus promoting the filter process. COD Chemical Oxygen Demand. The COD is the oxygen equivalent

of that portion of the organic matter in a sample that is susceptible to oxidation by a strong chemical oxidant.

Colour The colour of the water aesthetically effects the potability. It is usually checked against a standard solution in Nessler tubes.

Colloids Suspended materials (between 10-3 mm and 10-6 mm in size) in the water that behaves like a true solution, such as passing through a filter paper, migrating under influence of a potential gradient etc.

Compaction In reverse osmosis compaction refers to membrane compaction, mainly due to temperature and high pressure (water hammer).

Composite Membrane Membrane obtained precipitating a thin active layer on a porous supporting layer.

Concentrate The remaining solution with the retained salts (also called brine, or retentate, or reject).

Concentrate Recirculation A part of the concentrate leaving the modules goes to drain, while the other part is added to the suction side of the high pressure pump, thus increasing the feed flow to the modules.

Concentration Factor The CF is the ratio of the salt concentration of the feed flow to that of the concentrate.

User Manual for Seawater Reverse Osmosis Plant SRO-250 9 SPECIAL TERMS Conductivity (electrolytical) Conductivity is a quantitative measure of the ability of a water to

pass electric current. It is a measure of the total ionizable materials present in the water because of the direct relation between the dissolved electrolytes and the electrical conductivity of the water.

Degermination The use of either physical or chemical agents to reduce the concentration of micro-organisms and viruses with the purpose of control, disinfection, or sterilization

Dehydration Dehydration means that the fine pores of the membranes are not wetted. This may occur when the membranes have been allowed to dry-out, or due to high temperatures or high osmotic pressure.

Disinfection The use of any agents to destroy the infectivity of a material. This need not imply elimination of all viable microbes as, for example, in drinking water.

Double Pass RO System A system in which the permeate is further desalinated by a subsequent RO system.

Effective Pressure Amount of pressure exceeding the osmotic pressure of the solution

FAC Free Available Chlorine Feed water The water entering the modules. Flow Balancing Flux Flow rate per unit membrane area. Fouling The deposition of foreign matter on the membrane surface,

resulting in changed membrane performance. FRC Free Residual Chlorine Fresh Water Natural occurring water from deep wells, boreholes, lakes, and

rivers. TDS less than 800 ppm, typically not over 600. GPD Gallons per day; 1Gallon (US) = 3,785 l Hardness Caused by the presence of soluble salts of calcium and

magnesium. Causes deposits and scaling. Jackson Turbidity Unit / JTU Measuring unit for turbidity measured with Jackson Cartridge

Turbidimeter Membrane Common materials used for desalination are cellulose acetates

and polyamide Membrane Degradation Decrease of strength and rejection performance due to changes

of the molecular structure in the polymeric materials involved (loss of molecular weight)

Module Pressure vessel containing membrane element(-s). Permeate Permeate is the product water obtained by the reverse osmosis

process, in desalination also called product. Permeate Backpressure Pressure on the permeate side of the module (or the plant). Permeate Channel Spacer The fabric that mechanically supports the membrane and drains

the permeate to the permeate tube. pH Measure of the acid or alkaline nature of a solution. At 25 °C a

solution with a pH of less than 7,0 is acidic while a solution with a pH higher than 7,0 is basic.

User Manual for Seawater Reverse Osmosis Plant SRO-250 9 SPECIAL TERMS Polymer Creep Long-time changes in the molecular structure of polymeric

materials due to mechanical stress and pressure. Post-treatment In reverse osmosis desalination this designation refers to

processes applied to treat the permeate (chlorinating, etc.) Potable Water Drinkable of potable water is water fit for human consumption. It

must be free from organisms and concentrations of chemical substances hazardous to health, of agreeable taste and odour, without turbidity, colourless. The TDS is less than 500 ppm.

PPM Parts per million. A measure of concentration which, in the field of water treatment, is nearly equal to mg/l.

Pressure Vessel The vessel containing one or more individual membrane elements.

Pre-treatment Processes applied on the feed water, like filtration, softening, coagulation, etc.

PSI Pounds per square inch, ! PSI = 0,069 bar PSIG Pounds per square inch gauge. Difference between operating

pressure and atmospheric pressure. Pyrogens Contaminants causing fever Raw Water Untreated water from wells, surface sources or the sea. Recovery Ratio of the permeate flow rate to the feed water flow rate Rejection Factor Percentage of the total dissolved solids in the feed water which

are rejected by the membranes. Reject See concentrate Saline Water Brackish water, sea water or brine containing more than 1000

ppm TDS. Salt Passage See System salt passage. Scaling Deposition/Precipitation of minerals and other solids on the

membrane surface. Scale Inhibitor Chemical preventing the precipitation of solids, especially

calcium carbonate. SDI Silt Density Index Sea Water Ocean water of a high salinity, generally assumed to be 35000

ppm TDS. Sea water salinity varies with the location, e.g. Atlantic Ocean approx. 36000, Baltic Sea 7000 and Red Sea 43000 and higher.

Semipermeable Membrane Membrane rejecting one or more components of a solution. SDI Silt Density Index, an index indicating the content of colloidals in

water. Shock Treatment Shock treatment in desalination is the addition of a biocide into

the feed stream for a limited time period. Spiral Wound Membrane Multilayer membrane for reverse osmosis with axial brine flow

and radial permeate flow. Standard Sea Water Sea water with a salt concentration of 34500 TDS and 19000

ppm chlorides, used as basis for concentration calculations. Sterilization The use of any agents to kill or inactivate all viable micro-

organisms and viruses within a sample. System Salt Passage System salt passage is the concentration of a compound in the

permeate related to its concentration in the feed water.

User Manual for Seawater Reverse Osmosis Plant SRO-250 9 SPECIAL TERMS

Telescoping Telescoping may occur with spiral wound elements, where the outer membrane layers of the element can unravel and extend downstream past the remaining layer. Telescoping is caused by excessive pressure drop from feed to concentrate.

Total Dissolved Solids TDS The amount of solids contained in a solution, usually determined by evaporation and subsequent weighing of the residuals. There is no generally accepted process, the temperatures vary between 105 °C and 180 °C. Due to the hygroscopicity of the residuals the TDS is slightly higher than the corresponding salinity.

Turbidity Suspended insoluble materials mainly occurring in surface waters.

Ultrapure Water Water with a TDS of less than 50 and a conductivity of less than 0,1 mhos/cm

Water hammer Water hammer in reverse osmosis systems means ahydraulic shock to a membrane element

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