Hard Wiring the Reverse Osmosis System

Contributed by Tom Pierson

On several follow-up trips to my church’s sites in the Yucatan, I kept noticing that the hot terminal on the RO receptacle was burnt and causing a poor connection, necessitating replacement.  The older higher pressure membrane RO’s (160 PSI) draw over 18 amps @ 120 volts running and surge to three to four times this when starting.  This switched receptacle is rated at 15 amps.  During start-up arching occurs on the hot terminal, and over time will create a poor connection and reduce RO performance.  See photo below.

One solution is to replace this male/female connection with a twist lock male plug and matching receptacle.  The example below is a male 20 amp (220 volt) plug, commonly used on small emergency generators and available at home centers for about $30.

Another solution is to replace the existing plug and receptacle with a hard-wire  30-50 amp HVAC non-fused service disconnect box.  You can find an example by looking on the outside wall of your house near your air conditioning compressor.  This will give you the ability to quickly disconnect the RO for service and provide you good screw type connections between the Romex feed wire and the flexible service cord going to the unit.  There are several styles of disconnect boxes, including the pull type, shown below, the old style side lever and one that appears to have a double breaker, which is actually just an on/off double pole switch.  The pull type costs $10-$12.

Service disconnect boxes are easy to wire for either a 110 volt or 220 volt RO.  Make sure you make the flexible cord is long enough so the RO can be moved away from the wall for easy service access, once the unions are disconnected.  The flexible cord could also be attached to the box with a special type strain connector, instead of a Romex clamp, to avoid accidentally pulling the wires loose.  A simple trick is to also make your ground wire length shorter than the hot and neutral wires, to take the initial strain of accidental pull.

The 110 volt box is shown below.

The 220 volt box is shown below.

Pre-Wired Yucatan Ready Disconnect Box

Reverse Osmosis Membrane Washing

LWW recently got a question from one of our Reverse Osmosis and Softening (ROS) systems operators in the Yucatan. They asked the following:

The ROS system was installed in July 2012. The system operator was concerned about the membranes because the TDS was measuring ~50 ppm even after a softener regeneration. What does LWW recommend?

My short answer to the question was that the RO has probably lost some capacity in the last 8 months of operation. It doesn’t sound like it’s time to wash the membrane, but it is time to take notice and start or continue to take data on system operation. I said that they should plan on washing the membrane after a year of operation. This would be the washing process done by a trained person such as Carlos McGregor with acid and base solutions, overnight soaking, etc.

On the RO system, the regeneration of the resin in the softener protects the RO from Calcium and Magnesium contamination in the water. Calcium and Magnesium are the elements that show up as hardness in the water. These contaminates can foul a membrane very quickly and you can’t wash them out. For that reason, you need to measure the hardness of the water as well as the TDS after the regeneration. With a TDS of 50 ppm you could estimate the hardness at 20 – 30 ppm. I would say that 50 ppm of TDS in the product water is OK as long as you can’t taste any salt in the water.

As an experiment, try measuring the TDS in the waste water as well as the TDS going into the RO. You may be able to run a rough balance of TDS (in) = TDS (out). You could also calculate the %TDS removed and going down the drain in the waste stream. As long as the RO is removing 90% plus of the TDS, then the membrane is doing its job. (This assumes that you are keeping the waste flow about equal to product flow.)

The best way to determine when it is time to wash the membrane is to track the gallons per minute (gpm) output of the RO. If when you start out, the RO product water flow is 3.0 gpm, that is your baseline. The manufacturer says that when the product water flow drops by 10% to 2.7 gpm, then it is time to wash the membrane. The problem is that the drop in flow is very slow, so unless you are writing down data every week or more, the operator will lose track of how the system is performing.

Joanie Lukins added to this advice by reminding ROS system operators that it is recommended that water softeners should get an extra regeneration about every month. This extra regeneration uses more salt, but ensures that the resin is returned to full softening capacity extending the life of the membranes.

If there are other comments on this posting, please submit them.

Thanks, Ralph Young, Technical Director, Living Waters for the World

Adapting to Plumbing not Compatible with Schedule 40 PVC

When working in other countries it is not uncommon to encounter pipe that is not the same specification as the Schedule 40 PVC pipe used to construct the LWW water treatment system.  Normally the entire system will be built using Schedule 40 PVC pipe and connectors.  Sometimes the pipe used in-country may not match the diameter of the connectors entering and exiting the system to and from the tanks and the drain.  This is due to the fact that the outside diameters may be metric or otherwise different than U.S. Schedule 40 PVC, especially if it is not manufactured or sold in the U.S.  If you are not absolutely certain that the pipe you will encounter upon arrival to install is compatible with the system connections, you should insure that you have adapter hardware which will accommodate the differences.  The photo below shows the difference between “thin wall PVC” and Schedule 40 PVC.

For the purposes of this discussion we will assume the use of plastic or PVC pipe to do the pre-installation plumbing of the tanks to and from the system board location.

The simplest solution is to use a flex coupling.  This is normally a black rubber coupling with stainless steel clamps on both ends.  These are usually available for most common U.S. PVC pipe diameters (American Valve makes one for 1 inch Schedule 40 PVC).  Being made of flexible material, they can accommodate slight variations in the diameter of the pipes being connected.  Be sure to take extras for future maintenance as these may be affected by ozone over time.  Also insure that the pipe on each side of the coupling is anchored to prevent pressure from forcing the pipe out of either end.  There are many variations of these couplings and not all are recommended for potable water or pressurized environments.  Most of the potable water issues are based on taste considerations or because the manufacturer did not want to certify it for potable water.  It is felt that most of these couplings are suitable for this application.

Many countries utilize the U.S. NPT threading standard and commonly thread plastic pipes rather than gluing them.  Also, some pipe used in other countries is not PVC and the glue we use is not recommended for other materials.  If there is a possibility of having a 1 inch threaded connection on the pipes being presented at the system board, a variety of threaded, 1 inch Schedule 80 adapters (and other fittings) will accomplish the connection.  Schedule 80 threaded adapters are recommended as the walls are thicker providing extra strength when threaded.  These adapters come in a variety of connection combinations:  Slip, MPT (Male Pipe Thread) and FTP (Female Pipe Thread).  Carry several of each combination:

MPT/Slip       FPT/Slip       MPT/MPT (Nipple)       FPT/FPT          MPT/FTP

The same connection combinations are available in elbows and unions.  Combinations of these fittings should allow connection to pipes with male or female threads.

Ideally, you will determine and/or purchase the in-country tank-to-system pipe and tanks on the planning visit and can have a sample to bring back and use to pack the appropriate adapter hardware.  Only rely on this if you have actually purchased the materials or can be guaranteed that those exact materials will be available when the pre-installation work is actually done.

As a last resort, remember that PVC (and other plastic pipe) can be heated and swedged to a larger inside diameter to accommodate another sized pipe (similar to the swedged ends on some Schedule 40 PVC pipes).  The pipe with the larger INSIDE diameter (or thicker wall) will be heated while the other pipe can be “sharpened’ and used to swedge the opening of the heated pipe.  Take care not to overheat the pipe.  Swedge the opening for at least one and on-half inch in order to insure a sufficient gluing surface.

Last, but not least, remember that ONLY one inch pipe can be used for the tank-to-system plumbing.  Any smaller diameter can adversely affect the flow rate and impede the efficiency of the venturi.

Contributed by Jerry Goode, Co-moderator of the Cuba Network

The Low Pressure WIKA Gauge

The low pressure WIKA gauge was first used in the Living Waters for the World Standard Clean Water System when we changed from a two-tank, two-pump system with the “green weenie” pumps to the one-tank, one-pump Standard System we know and love today.  With most of the clean water tanks located on the roof, Operating Partners wasted a lot of effort running to the roof to check the status and level of water in the tanks.  The WIKA gauge offered a way to save time by gauging the level of the tank by reading a pressure gauge on the board.

Over the years the WIKA gauge has had its ups and downs.  It wasn’t long before LWW discovered that the gauge was more sensitive than the other pressure gauges on the board.  The flow variation and the sudden starts and stops of the system resulted in the premature failure of the WIKA gauge.  This problem was solved by installing the gauge in a “T” in the line so that it could be isolated with a valve.  Closing the valve during normal operation ensured that the gauge was isolated from all the pressure changes in the system.  When the system was down, the valve could be opened to monitor the level in the tank.

At first, the WIKA gauge was a standard fixture in the Standard Clean Water System kit offered by FCI in Louisville.  As more and more systems went away from clean water tanks on the roof, the WIKA gauge was taken out of the Standard System kit and offered as a stand-alone item from FCI.

Today the WIKA gauge is described as follows.  “The WIKA Gauge is a low pressure  (0-200 inches water column) gauge used to measure the water level in a storage tank located above the system. This item includes the WIKA Gauge, a brass shut-off needle valve, a brass reducing nipple, and a brass to 1″ PVC adapter.”  The gauge and all the accessories sell for $60.00.

With the inventory of WIKA gauges down to four, it’s time to make a decision to stay with the WIKA gauge and restock the inventory at FCI or let it go and not reorder.

All CWU-103 graduates, system operators, and instructors are requested to vote on the fate of the WIKA gauge by replying to this post.

Vote YES to keep the WIKA gauge or

Vote NO to retire the WIKA gauge.

Comments on this decision are most welcome.

Thank you and have a Merry Christmas and Happy New Year from Living Waters for the World.

Please don’t forget to send an E-card to friends and family.

The WIKA gauge is shown in the photo below near the top/center.

Board Construction Tips by Tom Pierson

For the most part, construction of a Living Waters for the World Standard Board is not difficult.  Once you get the major equipment oriented and mounted on the board, the devil is in the details to connect it together with the water source, the water tanks, and the bottling area.

Tom Pierson from Versailles, Kentucky has developed a couple of construction tutorials on mounting PVC pipe and the American Ball Valves.  For mounting PVC pipe, he has developed a training board for Clean Water U that highlights the various options.  Shown below is a picture of the demonstration board.

Teams are reminded that pipe and conduit are measured by the Inside Diameter (ID).   A 1″ PVC water pipe is approximately 1 1/4″ Outside Diameter (OD).  The gray colored clamps are for PVC electrical conduit and work the best and are the cheapest.  The new snap clamp shown on the upper left is for 1″ PVC conduit or pipe and works well for making ceiling or wall runs to the tanks.  One person can pre-install and the insert the pipe a section at a time and make some really long runs with no help.  The “Rule of Thumb” for anchoring PVC pipe is to secure it every six (6) feet of pipe run.

Tom also routinely anchors his 1” PVC ball valves to the board using a mounting pad.  He secures each ball valve to a mounting pad with wood screws, making a cleaner and more secure board.  The pictures below show his approach.

I’m sure that there are many other LWW teams out there that have their own construction tips.  Please feel free to share by responding to the blog.

Let the clean water flow!

Another Safeguard for the Ozonator

One of the biggest dangers for the Living Waters for the World Standard Clean Water System with ozone disinfection, is having water flow backwards from the venturi, through the ozonator tubing, and into the ozonator itself.  Since the ozonator bulbs are not water proof, water migrating into them will short out the tubes making them ineffective for disinfection purposes.

There are currently two check valves in the system to prevent water from going in the backwards direction.  The first is a rubber, disk check valve inside the venturi body itself.  The second is the Kynar check valve that is in the ozonator tubing.  When these check valves are operating properly they allow air to flow one way through the ozone lamps and into the venturi.  See the pictures below for details.

The other safeguard for the ozonator is to drain the venturi section of piping between each batch while the system is shut down.  In the past, we have observed that water left in the system between batches can expand putting pressure on the check valve in the venturi.  This pressure was thought to cause premature failure of the venturi check valve.

In some cases, LWW has recommended that system operators disconnect the ozone tubing at the venturi between batches.  With a physical disconnect in the tubing, there is no chance of water migrating back to the ozonator.  The biggest risk is that the operator must remember to re-attach the ozonator tubing when they start the next batch.

With this blog entry, LWW introduces another safeguard for the ozonator bulbs.  LWW suggests that teams could install a manual valve in the ozonator tubing to provide a positive shutoff for the water flow.  This valve shown below is available in most Auto Parts stores in the lawnmower section.  Each connection to the valve is ¼ inch.  This means that the valve would have to be connected into the ¼ inch tubing adjacent to the venturi.  The picture below shows the valve as purchased from the store.

For his Cuba installations, Jerry Goode glued the valve to a plastic base and secured the valve base to the board.   You can see below that the valve stands out and will be difficult to miss.

As you consider this improvement and others, please feel free to share them by responding to the blog.

Let the clean water flow!

Case Study in Water System Selection

Water System Selection Case 1

You have an incomplete Water Issues Survey (WIS) with the following information:

Section 3 Summary
Water supply is connected to church through ½” galvanized pipe that runs from a municipal source under the concrete sidewalk. The water sometimes has a chlorine taste. The source for the water is a nearby lake. Water seems to be unavailable from 10 am to 4 pm on weekdays. No one knows if the water has ever been tested, but it does have a distinct chlorine taste at times.

Section 4 Summary
The pastor’s wife filled out the health questions. She is not a nurse and has no medical training beyond raising 4 kids.
There is a health clinic 10 miles away in another town. The clinic serves four towns in the local area. The clinic is open 4 days a week from 8 am to 1 pm and 4 pm to 7 pm. A nurse runs the clinic, but there is no doctor. The clinic is run by the provincial government and turns away many patients every day.
Church membership is 100 families. At least four families miss church or Sunday school each week because of sick children. The kids and adults usually have diarrhea or stomach cramps that last up to two days.

Water Testing Summary
The Test America tests on the water samples were consistent with the field test results.
The water hardness was 50 ppm (test strips) and 55 ppm (Test America).
The TDS was 75 ppm. (hand-held meter) and 73 ppm (Test America).
Total Chlorine was 1.5 ppm (test strips).
pH was 6.5 (test strips)
Nitrates were 2.0 ppm. (test strips)
There were no visible solids observed in the water sample even after it set for 30 minutes.
The Hach Whirl Pack showed no color change after 2 ½ days.

Discussion Questions

1. Which Clean Water System is appropriate for this site? What other equipment is appropriate?

2. Why do you think the Hach bacteria test was negative? What does the weight of evidence indicate?

3. Is there any significance to the ½” galvanized pipe raw water supply?

Answers for Discussion Purposes

1.  The Standard LWW System with a sediment filter is probably most appropriate for this site.  The system should include a Cistern Tank.  Disinfection could be done with either UV or Ozone.

I did not recommend the barrel sand filter (BSF) for pretreatment for two reasons:  The first was that the water sample showed no solids even after it was allowed to settle.  The second was because the water is being chlorinated before distribution.  Even though the source is a local lake, the town is probably doing some filtration along with chlorination.  After startup, the sediment filter should be checked weekly to confirm no solids in raw water supply.

2.  The Hach bacteria test was probably negative because the water sample taken that day was chlorinated.  The issue with this site is the inconsistent chlorination by the local authority.  The concentration of chlorine runs from zero to at least 1.5 ppm.  These people can probably detect chlorine in the water at concentrations as low as 0.5 ppm or less, so when they can’t taste it, the water’s probably not safe.

The weight of evidence from the health report by the pastor’s wife overrides the Hach test and shows that the water is not consistently safe.  In my opinion, it doesn’t matter that she is not a health professional.  How can you deny the observations of a mother?

3.  The ½” galvanized pipe probably means the water distribution system is adequate.  The water pressure should be good enough to fill a Cistern Tank to feed raw water to the system.  The issue with the water supply is the consistency of supply.  The Cistern Tank should have a float valve on it to shut off the raw water when the tank is full.

The 103 person should also consider how they will transition from ½” galvanized pipe to 1” PVC.  The simplest solution is some kind of flexible connector with two alligator clamps on each end.

 

 

½ hp Pumps versus 1 hp Pumps

Here is a correction to an earlier post on 1/2 hp pumps versus 1 hp pumps.

In an effort to buy more parts and equipment in-country, LWW teams are often faced with trade-offs. This is especially true for pumps. The standard LWW Clean Water System purchased from the Fulfillment Center includes a ½ hp centrifugal pump manufactured by Leader. The ECOJET 110 model is rated for greater than 10 gals/minute flow.  Please note the pump specifications at the end of this posting.

A supplier in Ghana recently was not able to get a ½ hp stainless steel pump which specifications would be close to our ECOJET 110.   The supplier did however have in stock ½ hp cast iron pumps and 1.0 hp stainless steel pumps.  The biggest concern our operating partner technician, Michael, had about the cast iron pump is the subject of rust. In some past cases, LWW agreed to go with the 1 hp even though it was against good engineering principles of efficient pump operation. The question is whether to install the 1.0 hp stainless steel pump or ½ hp cast iron pump.

The answer that LWW provided to the Initiating Partner (IP) doing the installation was the following:

The 1 hp is way over-powered for what the Standard Clean Water System needs. Effectively, the way LWW would deal with the high capacity of the 1 hp pump is to close the valves to reduce the flow rate that was needed and have the pump operate at a high head and low flow rate.  In this operating mode, the 1 hp pump requires about twice the energy to operate than a ½ hp pump and when flow  is restricted to accommodate the desired flow rates, the operating pressure is nearly double that of the ½ hp.

In regard to rust, when the cast iron pump has been idle, the first water pumped through it may show a little discoloration. The rust is temporary at startup and is filtered immediately during the Start-up and Fill Phase of operation. For the small amount that may be bypassed during recycling (Use Phase), it is insignificant as far as Iron (Fe⁺²/FE⁺³) contamination is concerned. The Iron (Fe⁺²/FE⁺³) is way below any detection level of the Iron test strips LWW uses. There is no health concern with these low levels of iron in the water.

In LWW’s opinion, using the ½ hp cast iron pump rather than substituting the 1 hp stainless steel pump offers an operational efficiency advantage.  In this case, availability, lower initial cost and better operation efficiency of the ½ hp cast iron pump in Ghana overrides any concern for a small amount of rust in the pump head.

(Special thanks to Andy Jordan for contributing this article.)

5.0 Micron Filter – Optional Cleaning Protocol

Under normal circumstances, the 5.0 micron filter will clog over time due to the accumulation of particulates in the “tortuous path” of the interior of the filter membrane. The 5.0 micron filter is protected from larger particulates by the trash filter. However, turbidity and suspended solids larger than 5.0 microns and smaller than the trash filter micron rating (the current rating is 20 micron) are allowed to pass through the trash filter and into the 5.0 micron filter.

In field observations, the raw and clean water tanks have been found to have solids (calcium, magnesium, mud, etc.) settle to the bottom over time. This sediment is caused by normal precipitation of the dissolved and suspended solids in the raw water. This residue can be disturbed and become suspended solids when the water tanks are refilled after being drawn completely down. This sediment buildup can introduce turbid water into the system with very high levels of suspended solids that are not caught by the trash filter or that may enter the filters during the transition phase of operation on standard ozone systems. This situation results in the 5.0 micron filter being clogged rather quickly and prematurely by the accumulation of these solids on the surface of the filter. These particles are too large to be drawn immediately into the interior of the filter.

In one instance, due to the lack of a replacement filter, it was discovered that the surface of the 5.0 micron filter could be cleaned and placed back in service with little or no degradation of its efficacy. This will, of course, depend on the size and type of the suspended solids.

Living Waters and manufacturers’ documentation indicate that the 5.0 micron filter cannot be cleaned. This is true for clogging of the interior of the filter, but if the contamination is concentrated on the filter surface, cleaning may be possible.

The following protocol should be followed when cleaning the 5.0 micron filter due to suspended solids contamination on the surface of the filter:

1. Examine the trash filter and water tanks for suspended solids and turbidity. Flush the tanks and lines if necessary.

2. Clean the trash filter thoroughly including the canister using the existing protocol.

3. Clean all sediment from the water tanks and establish a regular schedule to check the tanks for sediment and flush as necessary.

4. Flush the lines from the tank to the trash filter and the return line from the clean water tank

5. Prepare a 5 gallon bucket half full of clean, chlorinated water.

6. Remove the 5.0 micron filter. Exercise caution in handling the filter as it could contain a concentrated level of contaminates. It should be treated as infected and a biohazard. Use rubber gloves, if available.

7. Place the filter into the bucket of chlorinated water. The chlorine will reduce the efficacy of the activated charcoal (if any) in the filter cartridge.

8. Using a soft plastic brush, gently brush the accumulated solids from the surface of the filter until it is visibly clean.

9. Empty the bucket and repeat this process until the water in the bucket remains clear.

10. Rinse all visible residues from the 5.0 micron filter canister.

11. Install the cleaned filter and resume normal operation observing G1 to insure that the filter is no longer clogged (compare G1 to the last operator log reading prior to the filter clogging). If the G1 pressure level has not dropped substantially, this will indicate that the interior of the filter is clogged and the filter must be replaced.

12. Disinfect the bucket, brush, and all surfaces contacted by the filter during the cleaning process and safely dispose of the cleaning water and gloves.

13. Wash your hands thoroughly after this procedure using soap and chlorinated water. Use hand sanitizer, if available.

Contributed by Jerry Goode.

Problem with Trojan Max Ultra-Violet (UV) Units

A standard LWW system with ultra-violet (UV) disinfection recently reported that the power unit for their UV unit continued to beep even though the green light was ON.

We have seen a condition similar to this at CWU and it usually indicated that the electrical connection with the UV Lamp was at fault.  Specifically, the problem was with the ground lead in the connection.  Once a tight connection was made, the problem was corrected, and the beeping stopped.  In these cases, the red light stayed lit during the beeping indicating that the UV was not providing disinfection protection.

In the Guatemala report, the UV Unit continued to beep even though the green light stayed lit.

A check of the TrojanMax web site discovered the following:

“Trojan UV Max C4 System Beeping After Replacing Lamp, Power Supply Issue
If you have a Trojan C4 UV Max power supply (black box with two LED light indicators) that was installed between January 2009 and January 2010, it is possible that it could have an alarm fault and will not reset.
The problem occurs when the Trojan UV lamp has been installed for about 1 year.  After 1 year, the UV Unit will start beeping indicating it is time to change the UV lamp and quartz glass sleeve.  After replacing the Trojan lamp there is no way to reset this alarm, and the unit will just keep beeping. 

 Trojan will swap these with an upgraded power unit at no charge. You can contact Trojan directly via their website or toll free line 1-800-265-7246.”

LWW is in the process of checking their stock of Trojan C4 UV Max units to see if they were manufactured during the time in question.  As we find these units, LWW will contact TrojanMax to replace them.

We ask that all Initiating Partners with UV systems purchased from FCI alert their Operating Partners, so that they can take action to correct this problem.  We have alerted our In-country Coordinators, Claudia and Miriam, so that they will know how to respond.

The good news is that as long as the Green Light stays lit on the unit, it will continue to disinfect the water and protect the users.

If you have any other comments or questions, please contact LWW at

infolww7629@livingwatersfortheworld.org