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Fuels Vol. 4 Unit 1

Reverse Osmosis Water Purification Unit

QuestionAnswer
Which ROWPUs are specifically designed for the US Air Force? 601 WPES–20 and H-9518-2
How much water does each of the onion bladders hold? 602 3000 gallons
What chemical is added to the influent line of the multimedia filter to aid in the removal of suspended solids (turbidity)? 603 Polymer
What are the two operating positions of the backwash valve? 604 “Backwash” and “normal.”
Which valve regulates the pressure exerted on the RO vessels? 604 The “product regulate flow” valve.
Which valve regulates the amount of product water flow? 604 The “product regulate flow” valve.
What happens when the vent vessels valve is closed? 604 Closing the vent vessels valve forces water to go towards the RO vessels
What tests are taken using the standard color comparator kit? 604 Chlorine and pH
At what pressure will the high-pressure relief valve activate? 605 1100 psi
What is the main purpose of the high-pressure switch on the ROWPU? 605 It is a general protection device designed to protect the whole ROWPU from high pressure when the high pressure relief valve fails to activate
What could be the likely cause of the activation of the low-pressure switch on the ROWPU? 605 The raw water pumps or the booster pump fails to deliver adequate flow or clogging of the cartridge filter
What are the three types of water sources? 606 Seawater, brackish water, and freshwater
What is the TDS content of brackish water? 606 500 to 1500 ppm TDS
What is the purpose of the drain valves? 608 To dewater the unit prior to shipment
Which instrument do you use to calibrate the chemical feed pumps? 608 100-ml graduated cylinder
Which instrument you use to check for turbidity? 608 1000-ml graduated cylinder, otherwise known as the “turbidity tube.”
What is the trouble reading for raw water flow? 608 25 gpm or less
What should you do when the brine tank is full? 609 So you always have enough backwash water
What is the minimum allowable chlorine residual on product water? 609 Two ppm free available chlorine
At how many gpm should the raw water flow be once both raw water pumps are on? 608 27–40 gpm
What happens when filter cracks are allowed to develop in the multimedia filter? 610 Suspended solids pass through the multimedia filter and plug up the cartridge filter prematurely
How many hours can you operate the ROWPU without backwashing the multimedia filter? 610 20 hours
What is the quickest indicator of a crack in the filter bed of the multimedia filter? 610 A sudden increase in flow on the raw water flow gauge
How much differential pressure across the filter is acceptable before the multimedia filter needs backwashing? 610 10 psid
What action must be performed before the multimedia filter is backwashed? 610 The ROWPU must be shut down
What is the last step performed during shut-down procedures? 610 Raw water pump #1 is stopped
How long is the backwash cycle? 610 Approximately 13 minutes
What is the “telltale” sign of the need to feed citric acid? 611 Rise in product water pH above 8 or when n 20 hours of production time has elapsed
When do you stop feeding citric acid? 611 When the pH is back to 5 to 8
What is the lowest pH value allowed for the citric acid solution? 612 3.5 pH
You must not allow the citric acid solution to exceed what temperature reading? 612 120ºF
How long do you operate the ROWPU when rinsing acid out of the RO vessels? 612 10 minutes
What is the maximum amount of TDS allowed prior to filling the product water tanks? 612 TDS is below 1000 ppm
Which cleaning method should you use when the raw water source is high in dirt and silt? 612 The surfactant method
What are the two element cleaning methods? 612 Citric acid and surfactant
When should you replace the cartridge filter elements? 613 When the pressure differential across the filter exceeds 20 psi
What must you do to the cartridge filter cover before you loosen the bolts and remove the cover? 613 Mark the position of the cover onto the shell by scratching a line across the cover and shell with a nail
How many elements are in the cartridge filter? 613 8
When are the RO elements changed? 614 The RO elements are replaced when it is no longer possible to lower the TDS of product water below 1000 ppm using citric acid feeding and the element cleaning methods
What should you do before even attempting to replace the elements? 614 First, find out which elements are faulty/defective and see if just replacing those elements will be sufficient
What would be the cause of a high front TDS reading and normal rear TDS reading from their respective sample/vent lines? 614 Leak at front end connector preformed packing of RO element
(601) How many gallons per hour does the H–9518–2 reverse osmosis water purification unit produce (on the average)? 600 gph
(602) What is the capacity of the reverse osmosis water purification unit raw water pump? 30 gpm
(603) The movement of water through a permeable membrane from an area of lesser concentration to an area of higher concentration is called reverse osmosis
(603) What percent of organic materials in water is removed by the reverse osmosis water purification unit? 99
(603) Unless otherwise directed by medical authorities, how many parts per million of chlorine residual must you keep in the product water produced by the reverse osmosis water purification unit? 2 ppm
(603) Which chemical is used as a coagulant aid during the reverse osmosis water purification unit treatment process? polymer
(603) Sodium hex is fed by the reverse osmosis water purification unit chemical feed pump at the multimedia filter influent
(603) The optimum pH of water going through the reverse osmosis elements in the reverse osmosis water purification unit is between 5 and 8
(605) In which order do the high-pressure safety devices on the WPES–20 reverse osmosis water purification unit activate? High-pressure relief valve, high-pressure switch, rupture disc assembly
(606) Technically speaking, what physical impact does the choice of a clear water source have on the reverse osmosis water purification unit (ROWPU)? Less frequent backwashings will be realized
(606) How far away from the campsite should you set up the reverse osmosis water purification unit? 100 feet upstream
(607) What is the maximum total dissolved solids (TDS) the factory calibrated in-line TDS monitor can read? 3000
(608) Which technical order do you use when operating the H–9581–2 reverse osmosis water purification unit? 40W4–13–41
(608) What is the initial setting of all the chemical pump control knobs on the reverse osmosis water purification unit? 10
(609) What is the maximum reverse osmosis pump pressure that should never be exceeded when operating the reverse osmosis water purification unit? 960 psi (seawater), 500 psi (brackish water)
(612) Which reverse osmosis water purification unit pump is used to recirculate the citric acid solution during the reverse osmosis element cleaning procedure? backwash
(612) Once initiated, when do you stop the reverse osmosis water purification unit reverse osmosis element cleaning procedure? After 45 minutes has expired
(613) Cartridge filter replacement is indicated on the reverse osmosis water purification unit when the differential pressure of the multimedia filter exceeds 20 psid
(614) What occurs when the end connectors or the interconnectors of the reverse osmosis water purification unit get damaged by high pressure? osmosis
Created by: Scottydick