Tyson Foods Chicken Processing Facility
Before consulting with Ocean Arks International and the John Todd Ecological Design team in 2001, the Maryland Environmental Protection Agency levied several fines against Tyson’s poultry processing facility in Berlin, Maryland. Effluent from the Tyson lagoon was frequently out of compliance with MD-EPA standards and was unfit to discharge into Chincoteague Bay, a local fishing and shellfishing area.
With the help of John Todd’s Aqua-Restorers, Tyson Foods Inc. turned their sludge filled lagoon into a thriving ecosystem and compliant wastewater treatment site. Aqua-Restorers were installed to work in collaboration with existing traditional treatment elements. The result was a 95% reduction of contaminants, 70% reduction in energy use, 20% reduction in sludge production, and a discharge that complied with Maryland’s open water effluent parameters.
In this case, 25,000 native plants were chosen to create a balanced and complex aquatic ecosystem to provide habitat for a variety of microbial communities, all of which perform a unique function in the waste treatment process. Flotation, aeration and water circulation are used to accelerate the ecosystem’s natural ability to clean water. Operation and maintenance of the Restorers is simple and low in cost. Their ecological diversity results in a highly resilient system— one that is able to handle sudden overloads better than traditional systems. More recently, several local plants and turtles have migrated to the lagoon, creating a unique self-organizing eco-system.
South Burlington Municipal Eco-Machine
South Burlington, Vt.
Built with a grant from the US Environmental Protection Agency, the South Burlington Eco-Machine demonstrated high performance even in very cold temperatures. On a daily basis the sewage typically generated by 1,200 residents at 80,000 gallons was diverted from the city’s conventional waste treatment plant to the Eco Machine. The South Burlington Eco-Machine was built in late 1995 by Living Technologies Inc. and Dr. John Todd with Ocean Arks International undertaking scientific oversight.
Inside the greenhouse, the system used several stages to achieve stable nutrient removal. First, sewage flowed through aerobic reactors made of aerators and a variety of plants. In this environment lived a host of organisms that metabolized the waste out of the water. A clarifier then worked to settle out the solids. Afterwards, Ecological Fluidized Beds, developed by Ocean Arks International, provided the final polishing,
nitrification, and suspended solid digestion. The site served as an educational center for local schools and resembled a local garden center more
than a waste treatment facility.
Sewage flows to a greenhouse with two treatment trains, each with five aerobic reactors, a clarifier and three Ecological Fluidized Beds. The open aerobic reactors had aerators, planted with a variety of aquatic plant species in floating plant racks (over 350 species were tested, including flowering plants). The air and plants provide an environment that hosts a variety of organisms that digest the nutrients and pollutants in the wastewater. Biochemical Oxygen Demand (BOD), Total Suspended Solids (TSS) and ammonia nitrate were reduced in this stage of treatment. A clarifier follows the open aerobic reactors to settle out the solids.
Ecological Fluidized Beds (EFBs) in each train follow the clarifier for final polishing. Thus, the EFBs operate aerobically and provide the final polishing, nitrification, and suspended solids digestion. Designed to achieve stable nutrient removal, this Eco-Machine was cost competitive, alternative treatment to a conventional system. With its aesthetic beauty and lack of offensive odor, this system is compatible
with a residential environment. The South Burlington Eco-Machine was also used as a teaching tool for many different schools and universities in the region. Elementary through High School grade science students toured the facility for first hand lessons on ecology, engineering, and environmental stewardship. University students were given more involved assignments in the intricacies of each ecosystem, and research applications. The facility provided many students the opportunity to work in and around this innovative system.
Audubon Society Corkscrew Swamp Sanctuary Eco-Machine
The Corkscrew Swamp is a magnificent natural attraction. With its cathedral-like old growth cypress forest and abundant wildlife, it offers some of the best nature viewing and photographic experiences in the world. When it was established in 1954, it was a remote wilderness, attracting fewer than 10,000 visitors annually in its early years. By 1994 attendance surpassed 100,000 visitors a year. The increase in visitors overwhelmed the sanctuary facilities and the inability to handle waste water from the rest room facilities was an immediate, intolerable, and costly problem. Conventional options included two small “package” plants working in tandem, both running full speed during the tourist season, and one during the off season.
Dr. Todd proposed an Eco-Machine for Corkscrew Swamp Sanctuary that would occupy an area of only 70x70 feet, purify waste without additives, and recycle 90 percent of the purified water back into the restrooms for reuse in the toilets. This innovative system also cost substantially less than the conventional technology. National Audubon Society worked with Dr.Todd to design a treatment system unique to Corkscrew Swamp. Built within pristine wildlife habitat, the conventional systems raised alarm regarding its efficiency and reliability. Maintenance, chemical additives, the ultimate quality of the effluent, and the large amount of space needed were also major concerns. Corkscrew Swamp successfully turned their wastewater problem into a tourist attraction and asset. The Eco-Machine not only naturally purifies wastewater, but it also serves as a public education facility and butterfly aviary.
Waste is first pumped to two below-ground 10,000-gallon fiberglass tanks for initial anaerobic digestion, then to a series of 2,500-gallon tanks, each of which is aerated and supplied with bacteria, green plants from algae to trees,snails, shrimp, insects, and fish. Here ammonia and organic nitrogen are converted to nitrates. Water then flows into a 6th tank. Any remaining sediment is pumped back to the anaerobic tanks. The constructed wetlands consist of two 30’x30’ plastic-lined, artificial marshes filled with crushed limestone. The marshes are planted with typical wetland species from the swamp that remove the last vestiges of nitrogen through the root systems and convert them to harmless nitrogen gas. When the effluent exits these marshes, it is clean. But to satisfy state regulators, it is disinfected with chlorine, pumped to a holding tank, and then pumped to a chamber to de-chlorinate the water with sodium sulfite. The water is then recycled into the restrooms for flushing.
Flax Pond Restorer
Flax Pond is a fifteen-acre (6 hectare) pond in Harwich, Massachusetts that has been heavily impacted for decades by leachates from an adjacent landfill and unlined septage holding lagoons. By 1989 the pond was closed to recreation and fishing because of contamination caused by the daily intrusion of 295 m3(78,000 gallons) of leachate from the landfill (Horsley et al., 1991). The pond had low oxygen levels, high coliform counts, excessive sediment build up, and organic pollutants in the water column including volatile organic compounds (VOCs). Macro-benthic organisms were absent from many of the bottom sampling stations. Flax Pond had unusually high sediment concentrations of total phosphorus (300 times greater) and iron (80 times greater) compared with other Cape Cod ponds (K.V. Associates, 1991). Ammonia levels in the sediments were found to be as high as 8,000 mg/kg. The pond is delineated into an eastern zone and a western zone; the cloudier eastern zone is the predominant zone of impact from the landfill. The pond had a maximum depth of 6 meters and stratifies in its western end.
In the autumn of 1992 construction of the first Restorer was completed and anchored in the eastern end of Flax Pond. It employed a windmill and solar panels for electrical generation and was capable of circulating through its nine cells up to 380 m3 d-1 (100,000 gallons per day) of water drawn from the bottom of the pond. The first three cells were filled with semi-buoyant pumice rock that supported diverse benthic life including freshwater clams of the genera Unio andOnodonta. A slow release form of a clay-based soft phosphate was added to the media cells in the Restorer. Bacterial augmentation and mineral enrichment in the first three cells was frequent. The final six cells supported over two dozen species of terrestrial plants on racks. The Restorer was not operated during the winter months to allow the pond to freeze completely.
The impact of the Restorer on Flax Pond must be set against the background of the significant loading of pollutants into the pond resulting from leachate from the nearby landfill. Between 1990 and 2000 approximately 964,000 kg of alkalinity, 142,000 kg of iron, 44,940 kg of ammonia, and 1,095,680 kg of dissolved solids have entered Flax Pond via groundwater contamination. Given these levels of contamination we would expect significant deterioration of water quality, biological activity, and increases in sediment levels.
Despite the onslaught of groundwater contamination, Flax Pond has maintained its biological health over the course of the last decade. This is in part the result of the Restorer and in part the result of the cleaning up of the nearby unlined septage lagoons in the early 1990s. Ammonia levels in sediments have not significantly increased; the pH of the water and sediment has hovered around neutral; dissolved oxygen at sediment levels has increased; and organic sediment levels have been reduced. The pond supports healthy fish populations, water quality has been maintained to allow irrigation of a nearby cranberry bog, and microbial and macroinvertebrate activity in sediments has increased.
Harwich Septage Treatment Pilot Plant
As a means to provide assistance to the Town of Harwich in solving its septage disposal problems and demonstrate the efficacy of “solar aquatics” in adequately treating septage to the stringent standards required for groundwater discharge, Ecological Engineering Associates – a precursor to John Todd Ecological Design – implemented a Solar Aquatic System at the town’s landfill. Through the use of a combined aquaculture/constructed wetlands systems that typically employs bacteria, algae, zooplankton, aquatic plants, nonaquatic plants and animals for the removal of pollutants from a waste stream, this pilot study was specifically designed to treat the combined sludge and liquid pumped from residential and commericial septic tanks, or septage, which had been disposed of in lagoons. Housed within a greenhouse to allow for year-round operation, this pilot plant system ran from March 26, 1990 to July 31, 1992.
The majority of pilot plant operations were divided into two distinct phases: the start-up phase; and the routine operations phase. Initiated on March 26, 1990 and ending on April 26, 1991, the start-up phase was intended to be a period of system adjustment and acclimation to the septage. In addition to accomplishing its intended purpose, the start-up phase was extended for many months while numerous modifications were made to improve the workability of the system. Once a period of steady operating conditions and performance was achieved, the system was considered to be in the routine operations phase, however, due to the length start-up phase, the start of routine operations phase was determined administratively rather than solely on a technical basis. This phase began on June 1, 1991 and continued through March 31, 1992. After the routine operations phase, the pilot plant remained in open for four more month for a shorter, stress testing phase.
Data from the study indicated that throughout both the start-up and routine operations phase the Solar Aquatic System treated a total volume of 2.09 million gallons and provided a noticeably higher level of septage treatment that was previously provided by the former Harwich septage lagoons. Although the actual capacity of the system did not appear to be reached due to its inability to handle the solids loading associated with untreated septage, effluent characteristics on average met both the target limits and the expected permit limits for the ten months of the routine operations phase. The Solar Aquatic System achieved very high removal of BOD, total suspended solids (TSS), and nitrogen, as well as substantial removal of phosphorus. Furthermore, high quality effluent was maintained under a wide range of operating temperatures and loading rates during the routine operations phase, including the combination of low temperatures and high nitrogen loading rates.