Wastewater Mining and Reuse: Creating Benign Future Scenarios

- By:

Courtesy of Aqueonics, Inc.

Wastewater mining: In addition to being perhaps the most uninviting combination of words, it sounds like a most unlikely idea. But for almost 30 years, Aqueonics, now headquartered in Greenville, SC, has pioneered such systems, starting in the ’80s, with its first wastewater mining project.

For that project, Aqueonics provided an onsite or decentralized treatment system for a developer in California, working out a contract with the regional system that had run out of capacity and was trying to purchase more wastewater capacity.

“The regional system couldn’t do anything without having a major expansion,” says Jerry Trayham, Aqueonics’ owner. “They couldn’t just expand for one customer, using long-term public funds. As a result, Aqueonics interdicted the wastewater collection system for the city and brought it into our plant, peak-shaving the city’s load and providing treatment for 888 houses for the developer and then treating that water to a drinking-water standard. From there it is used for irrigating golf courses and the housing subdivision as well.”

According to Trayham, wastewater mining is taking wastewater reuse to another level. Wastewater reuse involves all the piping in a development bringing all the waste to a central plant, processing it, and then returning it only to that community or development. Wastewater mining is actually taking waste from multiple areas, not just one centrally located source, treating it, and then transporting it to other users.

Aqueonics uses a multistage aerobic trickling filtration followed by additional tertiary processes required by the specific applications. The system is made up of three fiberglass interior aerobic towers and three anaerobic towers; conventional framing forms the exterior. The towers are on the top level. Two floors below is a series of tanks, pumps, and piping.

The “mined” water coming out of the plant is reused for multiple purposes. Any processed wastewater leaving one of Aqueonics’ systems that meets drinking-water standards can be used for golf courses, greenbelts for commercial space, car washes, athletic fields, fire protection for buildings, department of transportation deicing solutions for aircraft, street cleaning operations, window washing operations, flushing of toilets, chilled water services, borrowed feedwater applications at power plants, or even drip irrigation of the trees in a forested state park or state forest area.

The Benefits of Decentralizing
Before constructing a regulated onsite system to service any number of houses, a developer must be able to prove that water will be coming into the project as well as going away. That is done by a regional purchase allocation from an existing regional system, or an onsite system is provided that is regulated through the National Pollutant Discharge Elimination System process.

Much of Aqueonics’ work takes place in areas of the United States where the infrastructure is not present and those municipalities or entities also have access to large tracts of land. They also work in areas where age restrictions are in place, such as retirement communities, that typically have fewer occupants and less water flow input.

Aqueonics builds onsite wastewater systems for the developer, installing them directly into the neighborhood within 50 feet of an inhabited residence. The building actually looks like a home in the development.

“Because we scrub all the process air and muffle all the noise, people never know that there is a wastewater treatment plant directly in their midst,” says Trayham. “The effluent or raw waste comes directly into the house where it is broken down through biological processes. Licensed operators check the plant at least once a day for about an hour and a half.

“We design the different models that we use, and the builder has several options: He can turn it over to a municipal utility and they can operate it; we enlist a public utility to purchase the system from him; or we provide the operators. In the latter case the operator would actually create a privately held service group for which licensed operators would be hired. The homeowner association would then be charged a fee for water and water treatment services that are in the regime fee.”

Aqueonics takes that processed water and returns it to the community for use in irrigation of lawns, or it’s placed in a subsurface discharge bin where it is used to recharge the aquifer. At some locations in New Jersey where the aquifer is being recharged this way, fixed beds have actually been landscaped into a putting green adjacent to the clubhouse for the residents. Therefore, according to Trayham, every bit of the landmass is recovered for recreational use.

“It’s a self-contained, extremely environmentally friendly and environmentally safe system,” says Trayham. “If you’re not going in this direction or a similar direction, what you are doing is not replenishing or recovering some extremely valuable resources that are being depleted.

“We offer an alternative to centralized wastewater treatment systems,” says Trayham.

Because some state departments of environmental health are bringing new regulations into effect, there is even more of a drive toward greater decentralization. “There is a broad issue. Since 9/11, if a terrorist wanted to disrupt anything, centralized water or wastewater systems offer the perfect opportunity,” says Trayham. “With a decentralized system, one unit so affected can be successfully shut down while others continue functioning. Much of the planning that is occurring now is done for what is called ‘maximum foreseeable loss for catastrophic loss condition.’”

Aqueonics considers itself a pioneer in the area of decentralization. From a managerial standpoint, some may feel it makes more sense to be a centralized wastewater system, but other factors make decentralization more logical, according to Trayham.

“Instead of having the public funding for that system driving the issue,” he says, “we bring it to the developer who then turns it over to some operating entity, and they now have a brand-new infrastructure with a new customer base that has absolutely no cost impact to the tax base, population, or publicly funded groups.

“It’s almost something of a libertarian mentality; the developer knows he needs it, he has a customer base, so he or she is now going to put all of this system in place: The water, wastewater, gas, streets, all the houses, all the commercial buildings, and then all those operating systems will be turned over to those groups that are set up to operate them.”

The biggest concern from the department of health and environmental conservation standpoint then becomes the long-term operating ability. If the regional authority has no interest in taking over the decentralized system, then who ultimately operates the plant? It is important to make sure that one of the three EPA models is met to guarantee that plant has an operating entity over the next 30-plus years.

That includes making sure the money is set aside for oversight, operation, and maintaining the integrity of the system so that no one simply walks away from the system and it becomes an environmental nightmare.

The size of the Aqueonics wastewater treatment facility determines whether or not there will be an onsite lab for monitoring or testing of the effluent. Any facility 150,000 gallons per day or greater requires an onsite lab. Anything below this amount is required to have a licensed lab that will do all the testing and verifying. For conditions where the water is to be used in an application in which it must be clean, data can be captured and evaluated every 10 seconds or less if needed, according to Trayham. “With our systems, we exceed the most stringent discharge requirements for any existing facilities in the world,” he says.

Wastewater Mining
Wastewater mining is starting to get much more of a reception in this country, according to Trayham, who believes we need to mine every gallon of water we possibly can for beneficial reuse. With the concept of beneficial reuse, every gallon of water that we drink produces 1 gallon of usable wastewater. “We’re not trying to sell the general public on drinking that water. Hospital systems typically use potable water for chiller systems to cool their entire building. Why not use processed wastewater for this basic cooling function? There are really so many uses to which this returned water can be put, whether it’s industrial wastewater or municipal wastewater,” says Trayham.

If a housing development is in close proximity to an industry with a great need for processed water, Aqueonics can provide that site with a water source from processed wastewater for its process conditions; it is no longer using potable water, and that source is no longer being taxed. “We are now using every gallon of water coming into the wastewater system and giving it to some user to use in lieu of taxing the potable water system, which is being depleted at a very rapid rate.”

In addition to drip irrigation and spray irrigation, Aqueonics uses direct stream discharge. In one Pennsylvania project, just outside of Philadelphia, Aqueonics sought a permit to discharge into a stream that was already classified as “aquatically dead.” The state would grant a permit only for limited discharge.

“Over a year and a half later, after we’d been discharging, they actually increased our permit amount. We changed the quality of the stream to make it aquatically safe again, and it started supporting fish and other water life,” says Trayham.
Because of the new regulations of the Chesapeake Bay watershed, low nitrogen and nitrate limits must be met. “Our water already does that, so we are trying to recharge the Chesapeake Bay through the discharge of our systems to increase that water quality,” says Trayham. “The bay is currently 42% aquatically dead due to nitrogen concentrations, algae blooms, and dissipation of dissolved oxygen that will not support the fish and shellfish life.

“The ecosystem we live in is extremely fragile,” says Trayham. “Aqueonics provides one important benefit in processing all our water to a drinking-water standard and making sure it remains at that standard.”

Recharging the Aquifer
In some places Aqueonics actually discharges treated wastewater to subsurface beds for recharging the aquifer. The secondary protection of the water source is the distance from the bottom of the beds to the physical aquifer, which means that there is a tremendous amount of natural filtration taking place in the ground once again.

One of Aqueonics’ most recent projects at Hampton Township, NJ, involved treated wastewater returned to the area’s aquifer. The Hampton Township project is currently more commercial in nature than residential, with mostly retail stores. New Jersey has laws specifying that no more than 2,000 gallons of septic water can be placed in the ground per day per site, according to Kenneth D. Martin, owner of Martin Realty Development and Construction Co. in Newton, NJ.

“As soon as we have a use of over 2,000 gallons, we need to either tie into a state, county, or some other type of municipal sewage system or build a private treatment facility,” says Martin. “New Jersey’s laws are also very tough on returning the wastewater to surface sources; they want it to go back into the ground. I looked around for someone to help me with that and found Aqueonics.

“Using the finished water for golf courses and other uses was not an option for us. We had to get the water back into the ground rather than let it run down the road. What is problematic about using the treated wastewater for something like golf courses or lawn water is that you must have storage capacity for that water during the 120 days of winter. One option is to store it in a pond and pump it out over the summer.”

Ideally, for Martin, the best situation involved getting the water back into the ground through percolation. This is done in the style of a septic bed, but the water is “swimming pool quality” and has no problems with digestion into the ground as a typical septic system might have. The highly impermeable shaley soil in the area proved challenging in percolating the treated wastewater. The solution was simply using larger beds and therefore surface area for getting an adequate volume of water absorbed into the aquifer.

The project will eventually be serving a large commercial and residential community. “What is occurring with that project is that the New Jersey Department of Environmental Protection [NJDEP] Wastewater Management Plan requires going through an amendment process to increase the flows from the original needed flow to what is expected or anticipated for the maximum flow,” says Trayham. “It’s also a fairly arduous process. What is important to know is the scalability of these systems; they are scaleable to any size, low up to high. There is no limit.”

Since Martin owned all his own earthmoving equipment and had all his own people onsite, it made more sense for him to do the work on the physical beds for aquifer recharge, based on Aqueonics’ design. “We will do a construction inspection and oversight,” says Trayham. “But his equipment and people did all the work.”

There are seven beds for discharging. They are dug out and a gravel base installed along with a petromat and other components. Next, a concrete distribution box fits at the end or middle of each one of those beds. A single pipe comes from the plant to each one of those distribution boxes.

The flow comes in, and on both sides of that vault are 4-inch PVC pipe connections to perforated lateral pipes running both north and south. They stretch the length of the bed, which is then covered with gravel, soil, and grass. “Based on piezometer well station readings for each one of the beds, we determine what the depth of groundwater is. The technician making such determination also determines how much distribution they will send to each one of those beds.

“If one bed, for instance, is getting more than the others, they’ll control the flow so that it’s reduced going to the one bed and they will distribute the other flow to other beds so that it’s even and you’re not taxing a particular bed, but instead distributing it as you need it. Four of the beds in this site are near football-field size and three are about half that size. The sizes are based on the hydrology of the soil. If the soils are very good and will receive water well, the bed size can be smaller,” says Trayham.

Though Aqueonics built the facility for treatment of 50,000 gallons per day, it still has the infrastructure ready to handle much more than that. “All the pipe sizes and everything else are ready, capped off, and ready to go outside the existing building, so that when the next phase comes, when they go to 150,000 gallons per day, we’ll add additional process cells without changing the building.

“We’ll make the process cells bigger, but the physical operation of the house is not going to increase and we will not touch the operational integrity of that plant. It will continue to operate, and once we add these process cells we open the valve and things simply start mixing and operating with what is already in place.”

The benefit to the developer is being able to adapt when other big box outlets are ready to come online. The only major challenge in that case is being sure all the requirements for the NJDEP are met, as well as any construction alterations.

“The money doesn’t have to be put up by the developer for any increase in treatment capacity until they actually need that increased capacity,” says Trayham. “We can do the same thing for a municipal utility authority [MUA].” A MUA may have an immediate need for treatment of 5 million gallons per day. But if the MUA realizes that due to the growth of a certain area, it needs to up this to 50 million gallons per day, it just builds what it needs today with the planning and infrastructure for the future so that as the market comes and the customer base is there, creating that windfall of cash, it has the money to build the additional phases as the need arises. “That is considered smart-growth planning,” says Trayham.

Development at Osprey Point Helps Keep Salt Water at Bay
Just as with the Hampton Township project, the Osprey Point development in southern coastal New Jersey also uses its treated wastewater to recharge the aquifer. Osprey Point in Seaville, NJ, is solely a residential site for residents over age 55, unlike Hampton Township, which so far is commercial only. Unlike the northern New Jersey site, Osprey Point has no problem with percolation into the area’s sandy coastal soils.

“This system is absolutely efficient,” says Bob Henzy, sales manager with Osprey Point Homes. “It saves on water as it discharges back into the groundwater system, which is especially important here because along the coast the local MUA discharges water directly into the ocean. That’s a shame; it should instead be recharging the aquifer. Just south of us, Cape May, New Jersey, has major problems with saltwater intrusion of their aquifer. In Ocean City, New Jersey, where the population balloons to one-quarter million in the summertime, the amount of water processed and sent back into the ocean is phenomenal. That water should be going back into the ground.”

According to Bill Schwab, coastal and marine geologist with the US Geological Survey, the more groundwater is used in coastal areas, the more the dispersion zone between fresh and salt water is going to migrate inland as groundwater is decreased. “On top of that is the impact of sea-level rise. Obviously, as sea level rises, so will the zone of dispersion of saltwater to freshwater as it migrates further inland. We are currently using remote sensing tools such as resistivity to actually try to map the shape and behavior of the groundwater in the submarine environment offshore,” says Schwab.

“What we are looking at from our office is the exchange between groundwater and the estuarine environment. There is exchange in the zone of dispersion, and if that exchange is either contaminated or loaded with nutrients, it can exacerbate the problem somewhat. There can easily be changes on aquifer systems near the coast and elsewhere depending on how much rainfall and usage there is.

“But if you think about seawater rising, added to increasing populations in the coastal areas, these indicate a significant growing impact on coastal groundwater in many, many areas. I think the increase in plans for desalinization plants—just to keep the groundwater flowing—shows what may be on the horizon as well,” says Schwab. “Any situation or operations where treated wastewater can be placed back into the seacoast aquifer is to be commended.”

Customer comments

No comments were found for Wastewater Mining and Reuse: Creating Benign Future Scenarios. Be the first to comment!