Problem: Stricter septage regulations caused loading problems for private and public haulers and municipalities.
Solution: Installation of septage receiving and treatment plants produce usable product.
When Michigan set strict statewide limits on the land application of septage — waste from septic systems — private haulers had difficulty finding locations to off-load the material they were hired to pump away. Some wastewater treatment plants had to refuse taking in privately hauled septage, because municipal hauling programs threatened to overload the plants.
John Campbell, a 29-year veteran of septic tank pumping, set out to find a solution. Campbell, founder of Big Fish Environmental (Charlevoix, Mich.), started developing an innovative and efficient septage receiving and treatment plant to help pumpers interested in developing their own septage receiving and treatment facility. After reviewing several septage receiving and treatment units, he chose to incorporate into his design the Honey Monster® septage receiving system manufactured by JWC Environmental (Costa Mesa, Calif.).
By combining proprietary equipment as part of a treatment process, Campbell was able to develop a self-contained plant that can receive septage from municipal, private, and industrial sources and provide treatment to create a Class A biosolids product.
“With the limited options, Campbell hopes to increase the availability of smaller septage receiving stations, making it easier for private and even municipal haulers to off-load septage quickly and process it further into biosolids that can be reused,” said Julie Woodcock, a JWC Environmental representative.
Producing Class A biosolids
In Campbell’s design, septage received from pumper trucks goes into the Honey Monster, where it flows into a two-compartment equalization tank. The unit’s high removal rate of inorganic solids and homogenization of organics helps the product meet U.S. Environmental Protection Agency (EPA) specifications for Class A biosolids.
The septage flows through a rock trap, where heavy items fall out. Rags, plastics, debris, and other solids are shredded by a Muffin Monster® grinder. Next, an Auger Monster® screen removes, washes, and compacts the solids, putting organics back into the wastestream, decreasing volume, and reducing odor. The auger’s tilt and swivel feature enables easy access for inspections.
“The hair removal in the auger portion of the Honey Monster resulted in virtually no downstream clogging,” Campbell said. “The screening ability also made our homogenizing process more consistent per slurry load.”
The first compartment of the equalization tank blends air and bacteria with the septage, creating a slurry, which is degritted in the second compartment. This slurry then passes through a series of mixing tanks for further aeration, biofiltration, mixing, and lime stabilization. Campbell continues testing to maintain the correct methodology in mixing aerobic microorganisms for treating incoming septage.
The final step is dewatering through a screw press to produce Class A biosolids. The liquid effluent is discharged to the collection system for further processing at the municipal treatment plant.
A first attempt
In 2005, Campbell built the first facility in Charlevoix. The city’s sanitary sewer had been mostly plugged with greasy buildup and deemed a good candidate for a test site, Woodcock explained.
“We put our process to the test and were receiving an average of 20,000 gallons per day [75,700 L/d] of waste from private septage haulers, local produce processors, and municipal waste, including fats, oils, and grease,” Campbell said. “We basically took and tested all the septage waste that no one else wanted to handle.”
After 6 months, the clogging was completely gone, with no additional grease buildup, Woodcock said. “Saving time and money, [the system was] a win–win for the haulers, municipalities, and the environment.”
Part of Campbell’s development process is achieving EPA Environmental Technology Verification, which at press time was in final approval stages. Biosolids produced at the Charlevoix plant are approved by the State of Michigan as Exceptional Quality, Class A biosolids and are being distributed over agricultural fields.
With testing and design streamlined, Campbell is eager to install more septage receiving facilities throughout Michigan and neighboring states.
“We have several different design packages that can be customized to fit specific applications,” Campbell said. These low-maintenance, small-footprint septage processing plants are a cost-effective alternative to land application of the untreated septage, he said.
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