An interview with William Spitzenberg and Jason Jaskowiak from the American Samoa Power Authority.
Will Spitzenberg and Jason Jaskowiak discuss non-revenue water losses, the old-leaking piped water system in the Pacific and building capacity to improve them, smart metering, wastewater treatment in the unique context of American Samoa, and the need for localised innovation to overcome these challenges.
- Will Spitzenberg has been working as the Chief Water Engineer at the American Samoa Power Authority Water Division for four years. He has a civil engineering background and a Masters in Environmental Engineering. Before his role in American Samoa, he worked on land development, sewers, roads, and dams in the United States. In the interview, he unpacks the challenges of responding to non-revenue water losses that affect the American Samoa Power Authority (ASPA).
- Jason Jaskowiak is the Wastewater Chief at the American Samoa Power Authority. He has an Associate, Bachelor and Masters degree in Science, Environmental Engineering and Civil Engineering, respectively. He is also a registered professional engineer in the State of New York. Mr Jaskowiak has previously worked for a primary consultant of the U.S. Department of Defense and as a private consultant on drinking water, stormwater, and remediation projects.
- The wastewater chief and the chief water engineer
- About the American Samoa Power Authority
- Non-revenue water losses: faulty meters, illegal connections, and pipes leaking into the lava rock
- Pressure controls, smart meters, and advanced metering infrastructure
- Sewage: UV primary treatment, septic tanks, and cesspools
- The pros and cons of a secondary treatment waiver
- Challenges with designing a sewage treatment system on a tropical island
- Non-revenue water strategies in the Pacific: water balances and good data management
- Wastewater strategies in the Pacific: changing centuries of learned behaviours
- Addressing the challenge of non-revenue water is a growing area of employment that the Pacific will need help with
- The need for local innovation in wastewater and sewage in the Pacific
- Advice: take time to understand the unique cultural and environmental context of American Samoa
Who are the interviewees, and what does their organisation, American Samoa Power Authority do?
Jason is currently the Wastewater Chief at ASPA. He has a background and university degrees in both environmental and civil engineering and has been on American Samoa now for about 3 years. Before that, he worked as a primary consultant for the Naval Facility East, and for the military, and he has been a private consultant in New York on topics including drinking water, stormwater and remediation work.
Will is the Chief Water Engineer at ASPA, has a background in civil engineering as well as a Master’s degree in environmental engineering. Before moving to American Samoa he worked in public-works-type projects, including water, sewerage, roadways, as well as dam design with the Bureau of Reclamation.
The American Samoa Power Authority (ASPA)
ASPA provides and manages both water and power, being the utility for all electricity, water, wastewater and solid waste on American Samoa. It has a single customer service department, which means that customers receive just one bill for all the services they use, and they need only come to the one location to pay for them all or to sort out any issues.
For ASPA staff the combined utility gives them the advantage of shared billing and shared resources. For example, wastewater and water engineers help each other out, and power engineers are on hand to help if the water and waste teams have any issues with their electrical equipment. And when the water and wastewater teams need to identify a household — for metering reasons or in relation to a cesspool or septic tank — they have access to the household through its electricity account.
As well as the customer service team, ASPA has the non-revenue water department and the wastewater department which have, or work with, teams responsible for:
- leak-detection — one team finds leaks in underground pipes and one team checks on the household meters and connections;
- meter reading;
- data collection and analysis;
- construction (such as fixing water leaks);
- inspecting householders’ cesspools or septic tanks;
- installing, or guiding householders to install properly functioning septic tanks;
- managing and maintaining septic systems, sewerage, UV reactors and secondary treatment equipment; and
- dealing with incessant corrosion from the salty air.
Public outreach by ASPA is important for both the water and the wastewater sections, For example, radio announcements tell customers when the water supply has to be shut off while leaks are repaired. Most people like to listen to the radio, and ASPA uses it to explain that the piping system is old, and to ask listeners to be understanding and to report any leaks they see or find along with their system or on the road. The radio is also used to warn listeners it is not safe to combine village water supplies and ASPA’s piped supplies, and as a result people call-in and report cross-connections. ASPA also has a Facebook page, and it is also producing a commercial to help build understanding.
In relation to wastewater and sewage, ASPA uses public outreach, including flyers and personal contact, to educate householders about
- the need for properly installed septic tanks rather than cesspools, especially those that may contaminate groundwater or surface-water resources; and
- that grease, personal hygiene products and harsh chemicals block up or damage septic systems and sewerage and should be disposed of elsewhere.
There is naturally resistance from people who have traditionally used cesspools for their sewage, and particularly also when they are expected to pay out of their own pockets for putting in the upgraded system if they are building a new house.
Will Spitzenberg: Non-revenue water losses are an important issue throughout the Asia–Pacific. How does ASPA detect and deal with this matter?
‘Non-revenue water’ is water in the piping system which for some reason is not being paid for by customers — either because of losses through leakage or because of meter errors or theft. We estimate approximately 60% of the water in ASPA’s pipes is being lost, largely because of leaks from the old piping system. ASPA has about 150 miles of water mains and about 150 miles of service laterals Most were put in over 60 years ago.
Our asbestos-cement pipes were put in around 1960. They are losing large volumes of water through leaks at the pipe-joints, which are located every 12 to 13 feet. We shut the valves and empty a length of pipe to repair a leak, but then re-pressurising the system introduces water hammer in these old pipes and creates more leaks along the line. It’s an ongoing problem.
The crazy thing is that the leaks may be as much as 200 gallons a minute but they don’t show on the ground surface. The water is pouring down into the lava rock and the pipes are buried about four to five feet deep. Our leak-detection team has to use an acoustic device to listen for the leaks. When the crew finds a leak they report it and then the construction crew comes, a day or two later, and repairs it. Most of our mains pipes are under the road, so they often do the leak detection at night to avoid the traffic in the morning. Sometimes customers call to report a leak and we have two plumbing contractors that ASPA has hired to fix those leaks — one for the east of the island and one for the west.
Non-revenue water is also lost when household meters are inoperative for any reason. We have another team that checks the water meters in the villages — they may be buried or may not be working properly — and replaces those meters. This team reports illegal connections they find, where families are tapping into the water without a meter. ASPA identifies the household through its electricity account and imposes a fine, a minimum of US$1000. If the household asks for a reconnection, our team puts in a back-flow preventer before installing the new meter.
We are seeing improvement in the volumes of non-revenue water in the areas we focusing on. For example, in one case we reduced the water loss from over 150 gallons per minute to 50 gallons per minute. The leak detection crew found a leak on the mainline that they estimated was losing about 80 gallons a minute. After repair, our analysis of the in-line water metering data showed a tremendous cut to that flow.
There is a small ‘silver lining’ to this situation in that 99% of American Samoa’s water resources come from groundwater, so you could say these water leaks into the lava rock are acting as recharge — very expensive recharge water!
Non-revenue water is going to be a problem for a long time and we have to keep on top of it continuously. You can’t just hire someone to do a one-off fix and go away again because leaks will recur. Instead, ASPA aims to minimise the losses and the inconvenience to the residents by (i) having its own detection teams — one going round the households and one out listening; and (ii) repairing the leak within 24 hours of discovery if possible and with the water shut off for no more than 4 hours during the work.
Will Spitzenberg: what types and brands of equipment and materials do you use for fixing these losses and what are some of the costs?
ASPA has been replacing the old water metering system so as to improve the way we manage the production and pressures. The EPA has been funding that project. There are 52 production wells in American Samoa and we are progressively replacing all their meters: the highest producing wells were done first.
Our new mag meters and variable frequency drives (VFDs) are working well. With these devices, we can control the flow from the production wells as well as the pressure in the system and that helps alleviate the water hammer that happens when the pressure fluctuates too much and causes new leaks.
The VFDs actually save us money on the electric side as well as saving water. We set the VFDs so they speed up the pumping rate if the water pressure drops to a certain point, let’s say 30 psi. Then once the pressure reaches, say, 50 psi, the motor is set to turn off again. For certain areas we can isolate the section of pipe that we’re working on, so we just shut a valve and not the entire system. The VFD will sense that the pressure has increased because the valve is closed, so it will slow down the motor.
We are using a smart meter called an iPerl, which reads water-use and has the advantage that it collects data every hour and we can download that to check on the hourly usage. The iPerl is a little bit more expensive than the old pipe meters but we think the investment will pay off itself in a few years. We are also hoping to start using advanced metering infrastructure (AMI). That will mean we can network our meters and see all the data in real time. That’s more expensive again and it’s the next step. A company called Sensus makes the iPerl and they also supply and help install an AMI system.
Once we have the AMI operating we will be able to use a SENSUS system called SCADA or a similar online program for integrating control and data acquisition. We will be able to see how much water is going to any given area and how much the consumers are using. The difference will be the leaks and we will be able to send out the leak-detection crew to find it. It helps when the areas are smaller because we can find leaks faster in a small length of pipe than a long one and it also should mean less of the pipe system needs to be shut off for the repair.
For leak detection, the field crews use small devices that look like metal detectors. You can buy them from a number of different companies throughout the world: for example, in the US, New Zealand, Australia, Germany. There is plenty of information online about them. They are relatively expensive, costing up to 20,000 or 30,000 USD per unit, depending on the model you get, but not expensive compared to hiring an off-island crew. The investment is well worth it. They are easy for a trained team to use.
We are also replacing the old asbestos-cement pipes, at a cost of 100 million USD. The old HTPE pipe also needs replacing and that will cost another 100 million USD. There are about 50 miles of pipe to be replaced and we are using PVC at the moment for that, on the basis that they should last at least 50 years. There is a new piping material being used in New Zealand and other areas, called PVCO. It’s better than PVC and we shall be using that in the future. For all the new pipes, of course, we also have to make sure they are bedded in properly for good support.
Jason Jaskowiak: how is sewage managed on American Samoa?
American Samoa is one of the few places in the United States that still has a waiver for secondary treatment. So we actually only need to have primary wastewater treatment. However, ASPA recently installed two UV reactors, one in each of our wastewater treatment plants. These are now providing disinfection, whereas a year ago there was no disinfection for our wastewater.
About 40% of people are serviced by the sewerage system and we are continually working to expand that system. Of the remainder of the population, possibly 30% have a proper septic tank and the rest have a traditional cesspool, which is a hole in the ground that the toilets run into. A cesspool doesn’t provide containment or treatment for the raw sewage.
In the last three years, we have been modifying households’ onsite treatment. If a household is not on the sewer systems, we would like them to have a septic tank and we are encouraging the family owners to build one. While they’re building it we come out to the site three to four times and inspect it and lend assistance to make sure the system is constructed properly.
It’s a feature of this island that, unlike on the US mainland, the water drains out of the onsite system very very fast unless it is constructed appropriately. Elsewhere, the usual problem is infiltration rates that are too slow, leading to a backup. But when the system drains too fast there is no time for proper microbial treatment, which means nitrogen and potentially E. coli could be contaminating the groundwater aquifers.
Our solution is to change the way the septic systems are installed. Here we deliberately create a barrier underneath the leach-field, by digging deeper and creating a barrier using a special material which is then compacted. This layer slows down the percolation to a suitable rate that is slow enough to inhibit the growth of a biofilm and provide treatment in those onsite systems.
It is a relatively expensive installation because of the extra work and materials, and the EPA covers the cost if it is replacing a formerly leaky system at an old home near a public water resource. However, people building a new home must cover the cost themselves. We work in with the local banks to make sure that the septic system is in the design when the householder takes out a loan, to ensure they’re prepared financially.
For septic tanks, ASPA provides free pumping once a year. That is more frequent than the ideal, but people here tend to misuse their systems by putting grease and inappropriate hygiene products down the drain. Ideally pumping would be done only every 3 to 5 years, or once every 10 years. It is worth noting that there is no need to add microorganisms after pumping. The bacteria return naturally, especially if no inappropriate products or harsh chemicals are going into the system.
Jason Jaskowiak: how is ASPA achieving compliant wastewater treatment?
As noted earlier, American Samoa has one of the few remaining waivers on secondary treatment, and until recently relied on primary treatment systems only. Now, as well as having installed UV reactors for wastewater treatment, we are upgrading one of our treatment plants to implement secondary treatment, as funding becomes available. The UV reactors have enabled us to meet all of our permit requirements for bacteriological concentrations in our discharged wastewater. In the past, there had been issues with the levels of Enterococci, the bacteria that survive better in saltwater.
ASPA expects we, along with other places, will lose the waiver on secondary treatment in the foreseeable future. Looking ahead five years ago, ASPA contracted an assessment of secondary treatment possibilities, but the product offered them then, fine bubbles effusion at a cost of 80 million USD, was unsuitable. It wasn’t innovative and it was unsuited to the limitations and the cost of electricity here.
Instead, I have designed a much more easily operated and cheaper method of achieving secondary treatment, using our existing infrastructure and just modifying it with the addition of some screening upfront. The key is to use two stages of screening to replace primary clarification, and then use those existing primary clarifiers for biological treatment and secondary clarification.
There will be one waste stream being physically screened. The first stage is called the step screen: it has about a half-inch opening, and all the wastewater goes through that screen. The second stage screen — which will be funded only when we think the waiver is about to be removed — will be even finer. It will be like a drum screen and provide an even better output. This type of screen cleans itself: the screen looks like a small escalator and it’s constantly moving and it cleans itself as it rolls around.
All that output will go into a trickling filter for biological treatment; then our existing clarifiers will clarify that secondary effluent; and finally that output will go into the UV reactors and out. The trickling filter could be a moving bed bio-reactor (MVVR), which is a trickling filter that’s filled full of water; but the type that requires more energy than others and a little more maintenance, with blowers and things like that. So the decision has not yet made. We hope the better quality wastewater passing out of this secondary system will reduce the amount of labour needed to maintain the UV reactors.
Overall, the more comprehensive treatment design is better for the environment here. In this region, UV is very commonly used for disinfection, because we are discharging to an environment with corals and endangered species. To use chlorine instead, you would have to first make sure the chlorine is in contact with the wastewater for a suitable amount of time and then remove it again so as to meet a very strict regulation on how much residual chlorine is left in the discharge water. Recently the EPA increased the strictness of that rule on how much chlorine can be discharged.
In hindsight, purchasing the UV reactors may have been a better decision than it seemed at the time. It achieves disinfection without adding anything to the water, essentially.
However, maintaining the UV units is challenging. For example, currently, we clean each UV bank once a week by cleaning one of its four banks of UV bulbs each day. Also, in less than a year, the exterior portions of the UV reactors have almost completely deteriorated in the salty air. So, we’re trying to battle that, find products to spray on them and new ways to keep them functioning. The systems have a lot of electronics obviously, and we use three air-conditioning units to provide temperature control. That all adds to our electricity bills.
Machinery we purchase to use here cannot have components such as hydraulics and certain bearings which we cannot maintain. It needs to be as simple a machine as possible and to be made with 3/16 stainless steel that’s been pickled to prevent corrosion. In areas here that are near the ocean, you can collect a handful of salt by running your hand down any wall. It’s a huge challenge.
Will Spitzenberg: any suggestions to help other Pacific agencies address non-revenue water effectively and at relatively low cost?
Having data is very important. They could sub-divide their water system into smaller and smaller areas, so they can see more easily where the water is coming from and the areas it’s going to, and then do a water balance. The American Water Works Association has a water balance spreadsheet, for example; the Pacific Water and Wastes Association may have something similar.
First, they need to do the sub-dividing on their map, based on the information they already have. Then they can go out and test it by closing valves and seeing what happens to the pressure along the line as a result, and then opening the valves and making sure that the water serves certain areas. That way they can home in on the areas where the water seems to be going.
Then when money is available they can start installing in-line meters, like we’re doing, to get more information. The in-line meters record a flow every hour, and that helps us see if the flow going to a given area is increasing or decreasing, and how much water is going to this area. Since we already know the number of customers in that area and their water use per month or per day, we can then see how much water we’re losing in that area and send in our leak detection crew to try to find the leak.
But first you must have some good information, a good collection of data, to help you sub-divide the system down to smaller enough units. Of course, to do this, each customer in the target areas must have a meter or else this method will not work so well.
In summary, there are four recommendations:
- Sub-divide the system into subsections in order to have really good data to be able to focus and target your efforts.
- Do the water balance: the AWWA or PWWA water balance spreadsheet can help you grasp the way the water is flowing.
- Put in as many meters as you can, suitable for each of the parts of the system: not only the in-line meters collecting flow every hour but also meters at the household level.
- And have a dedicated team making ongoing effort to continually address non-revenue water. Non-revenue water is not an issue you can come in and solve and walk away from, especially if you have an old system that you cannot upgrade immediately. Don’t give up on non-revenue water even though it is frustrating to work on a section and then on your return there to find that the losses have gone up again. It’s an ongoing thing. You’ve just got to keep at it…. and to understand that sometimes it’s going to get worse.
Jason Jaskowiak: any suggestions to help other Pacific utilities manage sewage and wastewater?
From my conversations with people in the Pacific and in Australia, it seems everybody could use a lot of help with their onsite systems, and how to improve them. I think that people need to understand how the suction is working and how the microbiological treatment is taking place so that they can better protect the groundwater below the septic tank or cesspool.
With regard to wastewater treatment plants, I think that there is a general lack of expertise which is preventing people being able to look at the system they have and innovate it to improve the treatment it achieves. There are not enough people with that skillset.
So the best way to improve is probably via the onsite systems. They are relatively commonly used, and gains can be made from looking at how they’re being installed — to make sure they’re protecting the groundwater.
It is also important to establish a way to force people into making sure their onsite system is functioning well. That’s not easy. At ASPA we can enforce it because we also handle power and water; that means ASPA can restrict people’s access to water and power until they have the proper septic system in place.
Will Spitzenberg: have you any advice for people who want to work on non-revenue water?
I would recommend going down to your local water department and finding out what the non-revenue water situation is like. See if you can get some experience with them. I think non-revenue water is going to be a growing area of work that will need a lot of help to make progress.
Water is an issue everywhere, and just producing more water is not the best solution, particularly when many utilities are actually losing part of that water. Saving the water that’s being lost is a better option than trying to build new infrastructure to filter water or to build new sources. Even in the US, a number of utilities are losing up to 40% of their water. I think the way to go is for utilities to focus on saving the water they’re already producing, rather than sourcing more. Save money, and also save resources. Doing the water audit using the AWWA or PWWA water balance sheet can show how much money is being wasted based on the water that is being lost. It is shocking to see how much money that is, every year, just because the utility doesn’t know where the water is going. That’s non-revenue water.
Jason Jaskowiak: have you any advice for people who want to work on wastewater and sewage?
Yes. My advice is just to be innovative. To come out and work in this type of region, you have to be able to look at the resources you have, look at the problems you face that you can’t change, and find ways to deal with them.
For example, there are plenty of septic options that would work very well in other places, but they’re not passive systems. That means they need a pump or you need to use electricity. Here, nobody will pay for the electricity, because that is the culture of the country, and similarly they won’t maintain the pump.
You really have to spend time understanding the culture and what works and what the challenges are, and then apply what you know. Don’t arrive in a new place and simply apply what you’ve been taught. Rethink it first, based on what you see you have to deal with.
Also, be willing to understand the constraints of the environment. For example, most people will just assume that if a septic system is draining away well, everything is fine. The common challenge is that it’s draining away too slowly. You don’t automatically think about the problems that are being caused when it drains away too fast — but that’s what you need to do here in this environment.
Wastewater treatment in American Samoa
Secondary treatment waivers
American Samoa has a waiver enabling it to bypass secondary treatment of wastewater. There are a unique set of circumstances that allow only primary treatment, however, there is the threat that the federal government may withdraw the waiver at any stage. As the experience with these waivers in San Diego suggest, their withdrawal is a complex issue for a number of reasons. Secondary treatment is not a perfect solution, and a resolution to these issues requires creativity to resolve and provides challenges for water managers.
Cost is also a factor. A 2007 EPA audit revealed that capital improvement budgets in American Samoa of 250,000 USD are required just to maintain the waiver; 5 million USD to partially remove it, and 14 to 24 million USD to completely remove it. This is a very significant investment for the 55,000 citizens of American Samoa. What further complicates the situations is that sewers only covers 40% of the island, with 30% connected to septic tanks of varying quality and the remainder to cesspools. For those who like detail, the audit will provide it. This letter from the Governor of the American Samoan territory to the US government demonstrates how complex this case is.
Jason highlighted how the island was negotiating a response to its wastewater treatment challenges with the US government. Recently, in an attempt to maintain the waiver, ASPA installed two large UV treatment plants, as well as a range of upgrades to the existing sewer system to disinfection water for release into the environment. While this also presents challenges, it represents an integrated approach to responding to water resources management issues that incorporates existing local capacity.
The report “Making a Visible Difference in American Samoa” by the US EPA shows how an incremental approach to resolving a series of interconnected problems is required.
Septic systems and cesspools and groundwater pollution
Although American Samoa has sewer systems, majority of the population use onsite treatment however in many cases these are cesspools or are a hole in the ground where the waste is piped to with no containment or treatment. This is a major problem and enables pathogens and nitrogen to contaminate groundwater. ASPA provides assistance to community members to design and install septic systems, to replace cesspits. People are taught how to construct them and maintain these systems, which were redesigned to include a ground barrier below a leach field to slow the percolation, form a proper biofilm, and protect the groundwater.
For established homes situated near important water resources, this is subsidised by the EPA, but not for new homes. The cost of septic tanks is also considerably higher than cesspools, due to the materials for the ground barrier and extra excavation. Beyond human waste, many households in American Samoa raise livestock such as pigs, using cesspools. This is an important aspect of working with local preferences if local behaviour change is to be achieved. Pigs are important culturally and practically in American Samoa. Sewer upgrades costs need to be borne by residents, through increased rates and are more expensive and not inclusive, so this is a complex issue.
Another factor is the collection of reliable data. Jason mentioned that cesspool inventories did not appear to be reliable, despite the importance of this information. One Pacific Islands survey reports that a high proportion of people in American Samoa know that high bacterial counts in groundwater are a major issue, but do not necessarily attribute cesspools to be the cause of the problem.
Designing a wastewater treatment infrastructure in a unique environment
Jason also discusses the challenges of bringing in new technology for wastewater treatment to the island in terms of the uncertainty around requirements for secondary treatment and potential withdrawal of the waiver as well as other factors such as:
- the pristine marine environment and strict controls on residual disinfectants, such as chlorine;
- maintenance of machinery in what can be a harsh coastal environment for metal, with the existing skills and capacity of staff;
- and identifying contextually appropriate solutions and cost-effective culturally relevant technical advice.
Jason talks about how the current solution was incremental and informed by a longer-term more holistic understanding of the American Samoa context, rather than solely technical parameters. The benefits of this approach are that it is consistent with the existing capacity
Integrated water quality management in American Samoa
For wastewater treatment plants, assistance needs to be long-term and genuinely take the lack of skills and knowledge into account and prepared for the unexpected.
However, primarily what is required is to improve onsite systems as a driver for visible improvements in water quality and groundwater resources. There is a need for American Samoa to understand the importance these systems are installed and maintained. Currently, ASPA only does this through restrictions on housing approvals
Site-specific design of the leach fields and barriers is required. People have been managing things their own way for hundreds of years and they need to know why it is important to change. “There is a need to understand the culture and what the challenges are, rather than just applying what you have been taught. There needs to be new thinking based on the context you are meeting”.
Non-revenue water losses, and the history of the water supply of American Samoa
Will started out by mentioning the scale and complexity of non-revenue water losses in American Samoa where up to 60% of the groundwater pumped from the 52 production wells in American Samoa is lost to leaks, illegal water connections, meter inaccuracies, and a lack of available information to respond to this. This is a global issue, and it is estimated that 45 million cubic metres of water, valued at 3 billion USD per day is lost because of these issues.
In American Samoa, there are about 300 miles of water mains and service laterals. Some were installed by the navy in the early 1900s, which are still being used now and mostly leaking. In 1963 a USGS reconnaissance report was developed as part of the process of expanding the water supply through laying asbestos cement (AC) pipes, which were popular at the time. These are now also prone to leak at the joints. Their repair is delicate, and when they are re-pressurised, more leaks can easily form. The replacement of the AC pipes alone has been costed at 32 million USD, so it looks like it is a problem that is not going away soon.
The current approach to addressing this problem is through two non-revenue water teams who use acoustic leak detection equipment to locate water losses, check and replace old water meters, communicate with the public, attempt to locate illegal water connections. A $1,000 fine as a deterrent to connect illegally is not always effective. The teams have a turnaround time of between 24 and 48 hours to repair leaks. Good community relationships can make this task easier.
For a detailed description of their work see the ‘Scope of work for leak detection services for the American Samoa Power Authority (ASPA)’.
Meters and valves
Will mentioned in the interview about some of the water metering technologies used as strategies for ASPA to maintaining the water supply system in American Samoa and address non-revenue water losses.
- Magnetic flow (mag) meters use electromagnetic principles to measure flow based on the conductivity of the water in the pipe. They can enable flow information to be collected remotely and be connected in a system to more easily detect leaks.
- Check valves are often used in conjunction with VFDs (described below) to minimise problems with water hammering, that can often be the cause of leaks.
- Variable frequency drives (VFDs) detect water pressure in pipes and can send signals to vary the flow in response. The pressure is ramped up and down rather than switched on and off, which places less strain on the pipes. This enables APSA to isolate different parts of the piping system for fixing leaks, optimising how water is distributed, and even test different areas of the system to search for leaks. They reduce non-revenue water losses by making repairs more predictable and manageable and decrease the energy usage of the supply system.
- Advanced Metering Infrastructure (AMI) combines all of these components into a connected system. They can be very complex, but produce immeasurable benefits regarding improving water management. Currently, APSA is using smart meters called ‘iPerl‘ that collect downloadable information from pipes every hour.
The Environmental Protection Agency (EPA) has a metering project that is being built as resources allow. This can help to plan for the sustainability of groundwater reserves and manage the entire watershed in American Samoa in a more integrated way.
As a systems approach to solving the issues related to non-revenue water in American Samoa, there is a lot that can be learned from these experiences. Both technological and knowledge exchange initiatives should continue to be promoted
In American Samoa, the permeability of the lava rock means that leaks are rarely detected above the ground. Replacing the pipes as one of the root causes of the leaks has been costed at over $100 million dollars. There are generations of different piping approaches in American Samoa; from the cast iron pipes of the 1900’s to the asbestos cement of the 1960s; to high density polyethylene (HDPE) pipe are now causing problems and are in need of replacement; to the PVC pipes currently being installed that have a lifetime of 50 years; to new PVC-O pipes.
This “State of the Science: Plastic Pipes” document produced by the Water Research Foundation has more information than you ever thought you needed about this topic. Will refers to PVC-O pipes as being the next piping technology upgrade they are looking toward to address some of these issues.
Will refers to improved access to data about the water supply system as the most important thing that is required to improve non-revenue water loss issues. Being able to sub-divide or isolate parts of the system to a subsection to understand where the water comes from and goes to, where the leaks are and why they are occurring in defined areas is a gamechanger. He refers to the AWWA water balance spreadsheet as really very useful and mentions that the PWWA also has a similar resource.
Mapping the results of this is also important to understand where to allocate resources such as leak detection crews. When results are achieved and more money comes in, you can start to address problems. Having a really good baseline is the key. These improvements are all part of benchmarking water utilities. The ‘2012 Pacific Water and Wastewater Utilities Benchmarking Report’ by the PWWA is useful if this is of interest. The International Water Association’s Water Loss Task Force is also a good resource for practical approaches the reducing non-revenue water losses.
Will provides some tips for those using these systems:
- Subdivide sections to get really good data to inform action and target your efforts.
- Use the AWWA or PWWA water balance spreadsheet
- Learn about the inline water meters that can collect flows every hour and install them in key areas
- Implement smart meters at the household level and actually just meter everything you can.
- Having a dedicated team and an ongoing effort focussed on non-revenue water as something that really needs to be addressed. It is not just something you can walk in solve and walk away.
- Don’t give up. Just keep at it, especially if you have an old system.
- Non-revenue water is going to be a growing area in the future that everyone is going to need help with. Recovering water that is being lost is better than building new infrastructure to produce more water.
This interview and related content was originally part of the Kini Interview Series. Kini is a retired brand of the AWP and IWCAN.