Installations

 

Reverse Osmosis 

User’s Manual

PURITECH

RD800, RD1500, RD2000

INTRODUCTION

Your compact commercial reverse osmosis system is a durable piece of equipment which, with proper care and maintenance will last for many years.  These systems are part of a family of reverse osmosis units designed for operation with fresh feedwaters having TDS values below 2,000ppm. Models are available with permeate outputs of between 5,000 and 20,000 litres/day as shown in the specifications tables.

SAFETY

The Safety section of this User’s Manual outlines the various safety headings used throughout this manual’s text and are enhanced and defined below:

NOTE: Indicates statements that provide further information and clarification.

CAUTION: Indicates statements that are used to identify conditions or practices that could result in equipment or other property damage.

WARNING: Indicates statements that are used to identify conditions or practices that could result in injury or loss of life. FAILURE TO FOLLOW WARNINGS COULD RESULT IN SERIOUS INJURY OR EVEN DEATH.

All electrical works should be performed by a licensed electrician and conform to all relevant electrical safety regulations. All plumbing works should be performed by a licensed plumber and conform to relevant plumbing codes.

LABELING

Do not under any circumstance, remove any Caution, Warning, or other descriptive label from the system.

SYSTEM SPECIFICATIONS

Systems for raw water TDS value below 2,000 ppm

Model

RD800 A

RD1500 A

RT2000 A

Design

RT Frame

Vertical

Vertical

Permeate Flow (GPD / LPH)

800 / 150

1500 / 250

2000 / 350

Dimensions (LWH)

60 x 48 x 155 cm

60 x 48 x 155 cm

60 x 48 x 155 cm

Weight (approx.) kg

45

50

70

Element Size (in.)

4” x 21” TFC

4” x 40” TFC

4” x 40” TFC

Elements (qty.)

1

1

1

High Pressure Pump

Procon Pump

Procon Pump

Grundfos
CRI 3-23

Voltage

110V~410V

110V~410V

220V~410V

Hertz

50/60

50/60

50/60

Operating pressure (kPa)

760-1520 (adjustable)

Pre-filtration (standard)

20″ filter housings x 3pcs, 5 μm 1μm PP elements and carbon cartridge

RO Membrane Vessel

High pressure SS304 end port type, 2100kPa (300 PSI) rating

Flow Meters

RO permeate and Reject streams (optional for recirculation)

Pressure Gauges

Feedwater, membrane discharge (optional for pump discharge)

Electrical controls

Micro-processor based, overload breakers, LED indicators, TDS monitor

System Protection

Low feedwater pressure sensor, Automatic membrane flush, Inlet feedwater solenoid valve

Power

220-240VAC 50hZ single phase (optional 415VAC 3 phase)

Frame

AISI 304 grade stainless steel, electro polished

FEED WATER & OPERATION SPECIFICATIONS

Nothing has a greater effect on a reverse osmosis system than the feed water quality.  For lasting performance it is important to supply the system with the feed water quality shown below.  It is also important to feed the system the required amount of feed water. NOTE: It is very important to meet the feed water requirements.  Failure to do so will cause the membranes to foul and void the warranty.

CAUTION:If the feed water TDS value for your system is over 5,000ppm, it is suggested to install extra automatic permeate flush system to protection your membranes from membrane fouling. Contact your system supplier for more details about how to install automatic permeate flush system.

Feed Water Specifications

Hardness

<1 grain

Hydrogen Sulfide

0 ppm

Free Chlorine

0 ppm

Manganese

<0.05 ppm

Total Dissolved Solids

<2,000ppm

Organics

<1 ppm

Turbidity (SDI)

<5

Temperature

40°F – 80°F

pH

3-11

8°C – 27°C

Iron

<0.01 ppm

Silica

<1 ppm

These specifications should be met in order to have the reverse osmosis system perform optimally.  All operation specifications are based on the test conditions listed below.

Operation Specifications

Min. Working Pressure

35 psi

Max. Pressure

300 psi

Min. NaCl % Rejection

96%

Max. NaCl % Rejection

99%

Min. Feed (GPM)

1.5

Max. Feed (GPM)

10

Max. Hardness

15 Grains / Gallon

pH Range

3 – 11

Max. TDS

10,000 ppm

Max. Temperature

105°F

Test Conditions: Permeate flow and salt rejection based on 2000 ppm NaCl, 150 psi, 77°F (25°C), pH 7, and recovery as indicated.  NOTE: Higher TDS and/or lower temperatures will reduce the system’s production.

REJECTION, RECOVERY, & FLOW RATES

The amount of total dissolved solids (TDS) rejected by the membrane is expressed as a percentage.  For example, a 99% rejection rate means that 99% of total dissolved solids do not pass through the membrane.  To calculate the % rejection, use the following formula:

% Rejection = (Feed TDS – Product TDS / Feed TDS) x 100

NOTE: All TDS figures must be expressed in the same units, usually parts per million (ppm) or milligrams per liter (mg/l).

ROTEK™ commercial reverse osmosis systems are designed to reject up to 98% NaCl, unless computer projections have been run and provide a different rejection percentage. The amount of purified water recovered for use is expressed as a percentage recovery.  To calculate % recovery, use the following formula:

% Recovery = (Product Water Flow Rate / Feed Water Flow Rate) x 100

NOTE: All Flow Rates must be expressed in the same units, usually gallons per minute (gpm).

ROTEK™ commercial reverse osmosis systems are designed to have a recovery of 33% – 50%, unless computer projections have been run and provide a different recovery percentage.

SYSTEM COMPONENT IDENTIFICATION

No. Component Part Number

1

Inlet Pressure Gauge ON/OFF

2

RO Outlet Pressure Gauge CBMC3T220VHS

3

Power Switch GP35B25

4

Needle Valve (Concentrate Water Regulator) GP07B25

5

Permeate Water Flow Meter SMNV12F

6

Computer Programmed T.D.S. Controller CMSNPS203

7

Concentrate Water Flow Meter CSVNC04

8

Low Pressure Protection Switch P02507

9

Electromagnetic Protection Switch GF-CRI/CRN

10

Solenoid Valve CSWHNO

11

Pre-Filters FRP4040-300

12

RO Membrane + Vessel GFMDLZB05-CH

13

Rotary Van Pump GFMDLZB02-CH

14

1HP Motor HFET2034BL+F0CHO5-20

15

Auto Flush Valve NC04

UNPACKING AND INSTALLATION

PACKING LIST

  1. 1.Reverse Osmosis System.
  2. 2.½”Flexible PE Tubing (5 M).
  3. 3.Filter Housing Spanner.
  4. 4.Operating Manual.

Check that all components are present and in an undamaged condition.  If anything is missing or appears damaged, notify your supplier immediately.

INSTALLATION NOTES

  1. 1.Before installation, check that the power supply available matches the power requirements of theMost units are supplied as standard for 220-240VAC 50Hz single phase operation.  Options are available for 415V AC 3 phase power.
  2. 2.Ensure that all plumbing connections for the feed water inlet, permeate, concentrate and membrane flush outlets are secure and conform to relevant plumbing regulations.
  3. 3.Ensure that power lead is rated to carry the current draw of theA minimum electrical wire diameter of 3.5mm is recommended.
  4. 4.The external storage tank level contact switch should be connected to the blue wires labelled for tank connection and located inside the electricalDo not apply power to these wires as the connection is designed for a simple non-powered contact type closure switch only.
  5. 5.Use an external pressure booster pump if the feedwater pressure is below 150kPa.
  6. 6.If your feedwater supply is marginal, use a feedwater storage tank and booster pump to supply the RO system and prevent system cycling.

INSTALLATION PROCEDURE

Step 1
Connect the pre-treated feedwater source to the inlet solenoid valve using a ¾”male thread coupling. Use Teflon tape and leak sealant as necessary to ensure a leak-proof connection.
Step 2
Connect a length of ½”flexible PE tubing to the fitting on the rear of the front panel labelled ‘Concentrate’. Run this tubing to a nearby tundish to drain. There must be an air gap between the open end of the tubing and the tundish to prevent suck-back. The discharge point must be below the level of the outlet connection and within 2 metres of the installation.
Step 3
Connect a length of ½”flexible PE tubing to the fitting at the rear of the front panel labelled ‘Permeate’. Run this tubing into the treated water (permeate) storage tank.
Step 4
Connect a length of ½”flexible PE tubing to the outlet of the membrane flush solenoid valve and run this to drain via a tundish as described in step 2. The tundish may be shared with the ‘Concentrate’ stream.
step 5 Step 5
Take the blue wire from the wiring loom inside the electrical box and connect this to the float level sensor in the permeate storage tank. This allows the RO to turn on and off automatically according to the treated water storage tank level. Note that this connection is a contact closure only. Do not apply any power at any time to these connections.
step 6 Step 6
Connect the power supply to the contact breaker inside the electrical box. Ensure that the available power matches the power requirements of the system and that the power cables are rated to carry the current load of the system.

START UP AND OPERATION

SYSTEM OPERATION NOTES

  1. 1.Ensure that feedwater pressure is a minimum of 140kPa (20psi).
  2. 2.Check that your feedwater supply flow rate is sufficient for your particular model.
  3. 3.Check that the available power supply matches your unit requirements.
  4. 4.Re-check all installation instructions and that all plumbing and electrical connections have been made correctly and are secure.

System Operation

 

 

 

 step 01 Step 1

Loosen the breather valve(s) on top of the filter housing(s) to release any air pressure that may build-up when the system is started up.

This step will generally only have to be performed at initial start-up or where air may have entered the feedwater supply line.

step 02 Step 2

Turn the power switch on the front panel ON.  This will open the inlet solenoid valve and allow pressurised feedwater to enter the filter housing(s).  Once any trapped air has been vented from the filter housings, close the breather valve(s) on the filter housings.

step 03 Step 3

Once the unit is switched ON, it will go into an automatic membrane flush cycle for 40 seconds.  During this time the feedwater inlet solenoid valve will remain open, the membrane flush solenoid valve will open and the RO pressure pump will run.  While the membrane flush cycle is operating, the LCD will show a countdown from 60 to 0 seconds and all indicator lights will flash.

step 04 Step 4

After the membrane flush cycle is complete, the unit will close the membrane flush solenoid, check that sufficient feedwater pressure is available and go into normal operating mode

step 05 Step 5

If the system detects no error condition, normal operation will continue.  If an error is detected, the system will shut down until the error condition is rectified.  See “Troubleshooting” section for more information.

step 061

step 062

Step 6

Open the pressure regulator valve by fully turning anticlockwise.  When the system starts up, check flow rates and operating pressures for permeate and reject streams.  Close the pressure regulator valve slowly until the RO outlet pressure gauge reads 700kPa.  Check system flow rates.  Adjust the operating pressure gradually until specified system permeate flow rate is reached.  Use the minimum pressure possible for desired performance.  Ensure that the operating pressure on the RO outlet pressure gauge does not exceed the maximum specified for the system (generally 1400kPa).

Membrane pressure and flow rates may also be altered by opening or closing the RO pump outlet valve.  This valve is located on the discharge side of the pump.  Close the valve slowly to reduce the overall system output and membrane pressure.

 

Under most operating conditions the ratio between permeate flow and reject flow is between 1:1 and 1:3 and this ratio will vary according to feedwater quality.  The normal operating pressure on the system is around 1050kPa.

 

NOTE:  The system will automatically enter a membrane flush mode for 60 seconds after continuous operation for 12 hours.  This is to remove any sediment build-up that may have occurred on the membrane surface.  The system will continue to operate normally after this process has finished.

Microprocessor TDS Controller

micro processor

 

Display Description

Status Lamps

FULL                Alerts operator when the permeate storage tank is full.  The light will turn green and the
RO system will stop automatically.

FLUSH          This lamp is red while the system is going through an automatic membrane flush cycle .

PURIFY         This lamp is red while the high pressure pump (system) is operating normally and delivering raw water to the membrane(s).

INLET           This lamp is green when there is insufficient feedwater pressure.

MANUAL       Whenever the “Flush” button is pressed, this light will appear in red continuously until the flushing is done..

Control Button

SWITCH           This button switches the monitor display between Purifying Time (1=10mins, 99=990mins) and Permeate Water T.D.S. Valve.

 

FLUSH                While the system is purifying, this button can be pressed to do flush. After system flushed for 60 seconds, it will go back to purifying mode automatically.

 

RESET                 This button reset the purifying time to “0”.

Troubleshooting

If the system production declines or the system stops working, check the mechanical components for any visual problems.  Listed below are the items to check for any visual problems.  Listed below are the items to check for two of the most commonly encountered problem conditions:  Low system pressure and abnormal permeate flow.  Also refer to the reverse osmosis troubleshooting matrix on the next page.

LOW SYSTEM PRESSURE

Low system pressure occurs when sufficient feed water pressure and flow are not obtained.  This causes the high-pressure reverse osmosis pump to cavitate.  Failure to provide the proper feed will result in lower system pressure that may result in low production and poor rejection.  Check the following components:

  1. Pump:

Isolate the pump and determine how much pressure can be achieved.  This can be determined by checking the pump discharge pressure gauge at this point.  If the system is not equipped with this gauge, disconnect the hose that runs from the pump to the pressure vessel.  Install a pressure gauge.  The pressure of the pump must reach at least 190 psi when the flow is restricted.

  1. Pre-Filter:

Check the differential in the pre-filter gauges to determine if the filter needs to be replaced.  If the system is not equipped with these gauges, examine the pre-filter cartridge to make sure that it is not clogged and does not restrict feed flow to the pump.  Replace, if necessary.

  1. Low Feed Water Flow Rate:

Determine that the system is getting a sufficient volume of feed water.  Disconnect the feed water hose from the system and place it in a one gallon bucket.  Measure the time it takes to fill the bucket to determine the feed flow.  (Feed flow is measured in gallons per minute, so divide 1 gallon by the time in minutes to obtain the flow rate). Refer to the System Specifications for the required feed flow.

  1. Inlet Solenoid Valve:

Feed water enters the system through an automatic solenoid shut-off valve, which is normally closed.  Ensure that the solenoid opens when the reverse osmosis pump starts.  The system can be operated without the solenoid for troubleshooting.  Remove the solenoid to see if it is contributing to the problem.  Normally, cleaning the solenoid diaphragm will correct any malfunction of the solenoid.

  1. Electric:

Check to ensure that there are no electrical fuses blown and that all electrical connections are secure.  Use a voltmeter to verify that the motor is getting sufficient power.

  1. Pressure Gauge:

Check for foreign matter on the gauge fitting. Remove any visible matter and replace the fitting.  Verify that the tube is not pushed too far inside the fitting.  This could restrict flow and cause an inaccurate display.  If the fitting and tube are fine and the pressure gauge is still malfunctioning, the gauge should be replaced.

  1. Concentrate Control Valve:

The concentrate control valve may have a tear in the diaphragm.  Remove the valve, inspect the diaphragm, and replace if necessary.

  1. Motor:

The motor may not be drawing the correct current.  Use a clamp-on amp meter to check the current draw.

  1. Leaks:

Check the system for leaks, as this can result in low pressure.

Reverse Osmosis Membrane Troubleshooting

 

ABNORMAL PERMEATE FLOW

 

Permeate flow should be within 15% of the rated production, after correcting the feed water temperatures above or below 77°F.  Check your permeate flow meter to determine the permeate flow rate.  If the system does not have a permeate flow meter, measure the time it takes to fill a 1 gallon container then calculate the permeate flow rate at gallons per minute or gallons per day.

NOTE: To determine the temperature correction factor, locate the Temperature Correction Table in this User’s Manual and follow the directions.

  1. Causes of Low Permeate Flow:
    • Cold Feed Water
    • Low Operating Pressure
    • Defective Membrane Brine Seal
    • Fouled or Scaled Membrane
  1. Causes of High Permeate Flow:
    • Defective Product Tube O-Rings
    • Defective or Oxidized Membrane
  1. Causes of Poor Permeate Quality:
    • Low Operating Pressure
    • Defective Product Tube O-Rings
    • Defective or Oxidized Membrane

SERVICE ASSISTANCE

If service assistance is required, take the following steps:

  1. Call your distributor.
    1. Prior to making the call, have the following information available:
  1. Machine installation date
  2. Serial number (found on left-hand side of front panel)
  3. Daily Log Sheets
  4. Current operating parameters (i.e., flow, operating pressures, pH, etc.)
  5. Detailed description of problem
 

REVERSE OSMOSIS MEMBRANE TROUBLESHOOTING

Symptoms

Location

Possible Causes

Verification

Corrective Action

Salt Passage

Permeate Flow

Pressure Drop

Normal to Increased

Decreased

Normal to Increased

Predominately First Stage Metal Oxide Fouling Analysis of Metal Ions in Cleaning Solution. Improve pretreatment to remove metals. Clean with Acid Cleaners.

 

Normal to Increased

Decreased

Increased

Predominately First Stage Colloidal Fouling SDI Measurement of Feed Water. Optimize pretreatment for colloid removal. Clean with high pH anionic cleaners.

 

Increased

Decreased

Increased

Predominately First Stage Scaling (CaSO4, CaSO3, BaSO4, SiO2) Analysis of metal ions in cleaning solution by checking LSI of reject. Calculate max. solubility of CaSO4, BaSO4, SiO2 in reject. Increase acid addition and antiscalant dosage for CaVO3 and CaCO4.  Reduce recovery. Clean with Acid Cleaners.

Normal to Moderate Increase

Decreased

Normal to Moderate Increase

Any Stage Biological Fouling Bacteria count in permeate and reject.  Slime in pipes and pressure vessels. Shock dosage of Sodium Bi-Sulfate.  Continuous feed of Sodium Bi-Sulfate at reduced pH. Formaldehyde disinfection. Chlorination and de-chlorination.  Replace cartridge filters.

 

Decreased or Slightly Increased

Decreased

Normal

Any Stage Organic Fouling Destructive Element Testing. Activated Carbon or other pretreatment. Clean with high pH cleaner.

 

Increased

Increased

Decreased

Most Severe in First Stage Chlorine Oxidation Chlorine Analysis of feed water.  Destructive element test. Check Chlorine feed equipment and de-chlorination system.

 

Increased

Increased

Decreased

Most Severe in First Stage Abrasion of membrane by Crystalline Material Microscopic solids analysis of feed. Destructive element test. Improve pretreatment. Check all filters for media leakage.

 

Increased

Normal to Increased

Decreased

At Random O-Ring Leaks, End or Side Seal Leaks Probe test. Vacuum test. Colloidal material test. Replace O-Rings. Repair or replace elements.

 

Increased

Normal to Low

Decreased

At Random Recovery Too High Check Flows and Pressure Against Design Guidelines. Reduce the recovery rate. Calibrate and/or add sensors.

 

 

Appendix 1

 

Membrane Cleaning

 

Periodic cleaning of the membrane(s) can improve system performance.  In normal operation, mineral scale, biological matter, colloidal particles, and organic substances can foul the membranes and reduce performance.  The best prevention is to use a well designed pre-treatment system incorporating efficient sediment removal, de-chlorination (if chlorine based sanitisers are present), and softening or chemical dosing for the removal of scale forming minerals.

WARNING: Cleaning chemicals are dangerous and can cause injury and damage to the environment.  It is the user’s responsibility to comply with all applicable federal, state, and local regulations.

 

General Safety Precautions

 

  1. 1.When using any chemical indicated here in subsequent sections, follow accepted safety practices. Consult the chemical manufacturer for detailed information about safety, handling and disposal.
  2. 2.When preparing cleaning solutions, ensure that all chemicals are dissolved and well mixed before circulating the solutions through the membrane elements.
  3. 3.It is recommended the membrane elements be flushed with good-quality chlorine-free water after cleaning. Permeate water is recommended; but a de-chlorinated potable supply or pre-filtered feed water may be used, provided that there are no corrosion problems in the piping system. Operate initially at reduced flow and pressure, to flush the bulk of the cleaning solution from the elements before resuming normal operating pressures and flows. Despite this precaution,cleaning chemicals will be present on the permeate side following cleaning. Therefore, permeate must be diverted to drain for at least 10 minutes or until the water is clear when starting up after cleaning.
  4. 4.During recirculation of cleaning solutions, the temperatures must not exceed 50°C at pH 2-10, 35°C at pH 1-11, and 30°C at pH 1-12.

 

Organic Foulant Cleaning

 

The following cleaning procedures are designed specifically for membranes that have been fouled with organic matter. Review the general cleaning instructions for information that is common to all types of cleaning such as suggested equipment, pH and temperature limits, and recommended flow rates.

 

Cleaning Procedures for organic fouling

  1. 1.Prepare the cleaning solution as listed below.

 

Organic Cleaning Solutionn

  1. l Preferred 0.1% (wt) Soda Ash
    PH 12, 30°C maximum
  2. l Preferred 0.1% (wt) NaOH 0.025% (wt)
    PH 12, 30°C maximum

Notes:

1 (wt) Denotes weight percent of active ingredient.

2 Cleaning chemical symbols in order used: NaOH is sodium hydroxide.

 

  1. 2.Low-flow pumping. Pump mixed, preheated cleaning solution to the vessel at conditions of low flow rate (about half of that shown in Table 2) and low pressure to displace the process water. Use only enough pressure to compensate for the pressure drop from feed to concentrate. The pressure should be low enough that essentially no permeate is produced. A low pressure minimizes re-deposition of dirt on the membrane. Dump the concentrate, as necessary, to prevent dilution of the cleaning solution.
  1. 3.Re-circulate. After the process water is displaced, cleaning solution will be present in the concentrate stream that can be recycled to the cleaning solution tank. Recycle the cleaning solution for 15 minutes or until there is no visible color change. If a color change occurs, dispose of the cleaning solution and prepare a new solution as described in step 2.
  1. 4.Soak. Turn the pump off and allow the elements to soak. Soak the elements for 1-15 hours (soaking overnight will give best results). To maintain temperature during an extended soak period, use a slow recirculation rate (about 10 percent of that shown in Table 2). Soak time will vary depending on the severity of the fouling. For lightly fouled systems, a soak time of 1-2 hours is sufficient.
  1. 5.High-flow pumping. Feed the cleaning solution at the rates shown in Table 2 for 45 minutes. The high flow rate flushes out the foulants removed from the membrane surface by the cleaning. If the elements are heavily fouled, using a flow rate that is 50 percent higher than shown in Table 2 may aid cleaning. At higher flow rates, excessive pressure drop may be a problem. The maximum recommended pressure drops are 15 psi per element or 50 psi per multi-element vessel,whichever value is more limiting.
  1. 6.Flush out. Prefiltered raw water can be used for flushing out the cleaning solution, unless there will be corrosion problems (e.g., stagnant seawater will corrode stainless steel piping). To prevent precipitation, the minimum flush out temperature is 20°C. The system should be flushed for 1 hour.
  1. 7.The system should be restarted. Elements and the system need to stabilize before taking any data. The stabilization period will vary depending on the severity of the fouling. To regain optimum performance, it may take several cleaning and soak cycles.

Inorganic Foulant Cleaning

The following cleaning procedures are designed specifically for membranes that have been fouled with inorganic matter. Review the general cleaning instructions for information that is common to all types of cleaning such as suggested equipment, pH and temperature limits, and recommended flow rates.

 

Cleaning Procedures for inorganic fouling

 

  1. 1.Prepare the cleaning solution as listed below.

 

Inorganic Cleaning Solutionution

  1. lPreferred 2.0% (wt) Citric Acid
    PH 2, 45°C maximum
  2. lAlternate Muriatic Acid
  3. lAlternative 1.0% Na2S2O4

Notes:

1 (wt) denotes weight percent of active ingredient.

2 Cleaning chemical symbols in order used: HCI is hydrochloric acid (Muriatic Acid).

 

  1. 2.Low-flow pumping.
    Pump mixed, preheated cleaning solution to the vessel at conditions of low flow rate (about half of that shown in Table 2) and low pressure to displace the process water. Use only enough pressure to compensate for the pressure drop from feed to concentrate. The pressure should be low enough that essentially no permeate is produced (approx. 60 psi). A low pressure minimizes redeposition of dirt on the membrane. Dump the concentrate, as necessary, to prevent dilution of the cleaning solution.
  1. 3.Re-circulate.
    After the process water is displaced, cleaning solution will be present in the concentrate stream that can be recycled to the cleaning solution tank. Recycle the cleaning solution for 10 minutes or until there is no visible color change. If at anytime during the circulation process there is a change in pH or a color change, dispose of the solution and prepare a new solution as described in step 2. A pH of 2 must be maintained for the cleaning to be effective.
  1. 4.Soak.
    Turn the pump off and allow the elements to soak. Soak the elements for 1-15 hours (soaking overnight will give best results). To maintain temperature during an extended soak period, use a slow recirculation rate (about 10 percent of that shown in Table 2). Soak time will vary depending on the severity of the scaling. For lightly scaled systems, a soak time of 1-2 hours is sufficient.
  1. 5.High-flow pumping.
    Feed the cleaning solution at the rates shown in Table 2 for 10 minutes. The high flow rate flushes out the foulants removed from the membrane surface by the cleaning. If the elements are heavily fouled, using a flow rate that is 50 percent higher than shown in Table 2 may aid cleaning. At higher flow rates, excessive pressure drop may be a problem. The maximum recommended pressure drops are 15 psi per element or 50 psi per multi-element vessel, whichever value is more limiting.
  1. 6.Flush out.
    Prefiltered raw water can be used for flushing out the cleaning solution, unless there will be corrosion problems (e.g., stagnant seawater will corrode stainless steel piping). To prevent precipitation, the minimum flush out temperature is 20°C. The system should be flushed for one hour.
  1. 7.The system should be restarted.
    Elements and the system need to stabilize before taking any data. The stabilization period will vary depending on the severity of the fouling. To regain optimum performance, it may take several cleaning and soak cycles.

NOTE: Recommendations made here are specifically designed for the membrane elements inserted in the ROTEK reverse osmosis and nanofiltration elements. These recommendations, such as cleaning procedures and chemicals employed, may not be compatible with other brands of membrane elements. It is your responsibility to ensure the suitability of these recommendations and procedures if they are applied to membrane elements other than those which come with your system.

NOTE: No freedom from any patent owned by Seller or others is to be inferred. Because use conditions and applicable laws may differ from one location to another and may change with time, Customer is responsible for determining whether products and the information in this document are appropriate for Customer’s use and for ensuring that Customer’s workplace and disposal practices are in compliance with applicable laws and other governmental enactments. Seller assumes no obligation or liability for the information in this document. NO WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

 

Additional Information

Never recirculate the cleaning solution for longer than 20 minutes. With longer recirculation, the

carbonate scale can reprecipitate and end up back on the membrane surface, making it more difficult to clean. Carbonate scale reacts with HCl releasing carbon dioxide gas. Depending on the severity of the fouling, it may take repeated cleanings to remove all the scale. Cleaning severe scale may not be economical and element replacement may be the best choice.

Citric acid was originally used as a cleaner for cellulose acetate membranes and is not as effective with thin film composite chemistry. Further, it has a disadvantage of being a nutrient source for systems, which have biological fouling. It is, however, easier to handle than HCl and is included as an the primary cleaner for that reason.

Appendix 3

Recommended sampling procedure for bore waters

 

The purpose of this water sample is to correctly identify and quantify the contaminants that may be present in your feedwater.  To do this with any accuracy, the sample must be representative of the source water and not water that has been standing in the Pipework for any period of time.  It is also important to minimise any contact between the water and the atmosphere during sample collection.

  • The bore should be operating for at least 2 hours prior to sample collection
  • Make a note of any observations on the water exiting the bore and include these with your sample.  Things of note include:
    • Is the water milky, cloudy or coloured in appearance?
    • Is there any obvious sediment present?
    • Does the water have any noticeable odour?
    • Does the water cause any staining after contact with any surfaces regularly wetted?
    • What does the water sample look like after standing for 24 hours?
  • Use a clean 500ml plastic bottle with a well fitting lid to take your sample.
  • Write your name, contact details, date and sampling location on the bottle label
  • Rinse the sample bottle with fresh bore water several times.
  • Fill the rinsed bottle completely and seal immediately.  Tape the lid to prevent leakage
  • Complete this sample request form and attach to your sample.  Package sample and request form securely and forward to your test laboratory for analysis.

 

WARRANTY & GUARANTEE

The manufacturer of your reverse osmosis system guarantees that the product is free from defects in material or workmanship when operated in accordance with written instructions for a period of 6 months from start-up or 12 months from receipt, whichever is the shorter.  Parts that are not manufactured directly by the manufacturer of your reverse osmosis system will be covered by their manufacturer’s warranties.

For applications or water conditions other than those specified in the original purchase order for the reverse osmosis system, the User should consult with their local dealer or distributor to assess the suitability of the solution to be run in the membrane elements.  Limitations on pH and temperature can vary with membrane element type and the application of the equipment.  For special applications or for pH or temperature ranges outside the stated limits, the manufacturer may reduce the warranty period at their discretion.

A membrane element which fails to perform satisfactorily within the first 90 days after receipt that has not been mishandled, will be replaced free of charge except for freight and local labour on return to the factory.  A new membrane element supplied under warranty terms will carry the standard 90 day new membrane element warranty.  Any specified or implied warranties on membranes excludes but is not limited to scaling events, damage due to physical events such as water hammer or over-pressurisation, damage due to exposure to oxidising agents or pH outside the specified range limit, or incorrect placement in the pressure vessel.

If a membrane element is returned for warranty inspection, the User must obtain a Return Good Authorization (RGA) number from their dealer or distributor before returning the membrane elements.  The returned goods must be accompanied by a Returned Goods Form and be returned freight prepaid to the manufacturer.

The manufacturer will return any warranty replacement membrane elements to the customer prepaid. Membrane elements must be kept damp at all times and must be clean and sealed in a watertight bag before returning.  Only the manufactured approved cleaners, biocides, dispersants or other chemicals may be used with the membrane elements.  Use of other chemicals may void the warranty.  The User is responsible for being aware of the membrane element material and for ensuring that chemicals harmful to the membrane element are never in contact with the membrane elements.

It is the obligation of the User to maintain frequent operating data records. The manufacturer may request these records to substantiate any warranty evaluation. The User must notify their dealer or distributor at the very first sign of changes in operation of the system or membrane elements. Such notification should be in writing and should include all data requested on the operating log sheets.

To obtain a copy of the manufacturer’s warranty for their systems and terms and conditions, please contact your local dealer and distributor.


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