Case Studies - April 2020

Case Studies - April 2020

Housing complex meets effluent standards with hybrid system

Problem: The Massachusetts Department of Environmental Protection determined that the three conventional septic systems used by the Parker Terrace housing complex in Easton failed and were polluting the local groundwater. On top of needing to replace the existing wastewater infrastructure, the Easton Housing Authority also had new regulations to deal with, including reduction of total nitrogen and TOC. The system’s proximity to a municipal water well posed an additional challenge.

Solution: When factoring in the primary drivers for this project — effluent standards, cost efficiency, a small footprint and sustainability — Graves Consulting Engineers decided to install an AquaPoint Bioclere-OH wastewater treatment system. This multistage, hybrid system integrates AquaCELL aerobic and anoxic moving bed biofilm reactor chambers with two Bioclere trickling filters in between. Treated effluent flows through a tertiary-stage sand filter, activated carbon filters and UV disinfection prior to discharge. 

Result: Testing has shown levels of BOD, TSS, TN and TOC well below standards. In addition, the system helps offset other costs, as the effluent is used for irrigation throughout the grounds of the housing complex. 508-985-9050;

MBBR system eliminates effluent concerns at RV resort

Problem: An RV resort on a lake in Alabama was having problems with its old 35,000-gpd aboveground steel extended air package treatment plant. The effluent was poor, causing the soil disposal field to fail, creating serious odors around the resort and upsetting neighbors.

Solution: An engineering firm selected the Earthtek Environmental Amber MBBR system to replace the steel package plant. They choose the MBBR process due to cost effectiveness, minimal operations and maintenance requirements, and underground installation that eliminates odors. The system is installed in buried fiberglass tanks, which are impervious to corrosion and leaks. The system contains thousands of small plastic media pieces floating in aeration tanks that provide a large surface area for attached growth treatment. The media is self-cleaning and requires no maintenance, and the biofilm thickness automatically adjusts to variable flows and loadings. Excess biomass that sloughs off the media is settled out and returned to the primary tank for digestion. The system includes a 30,000-gallon, fiberglass-reinforced plastic primary tank to settle solids, store scum and provide anaerobic digestion; two FRP aerobic MBBR tanks to reduce BOD and ammonia; one FRP settling tank; chlorine and dechlor tablet disinfection; and a pump station to transport the treated effluent out into the lake for disposal.

Result: The system has performed as expected, eliminating odors and dispersing clean effluent. 812-528-8784;

Sand filtration utilized on wind farm maintenance facility

Problem: A maintenance facility for more than 270 wind farms in south-central Kansas needed a new septic system after the conventional field failed in a short time due to poor soils and excessive use. The maintenance vehicles used the yard for general maintenance, parking, turning and storing heavy equipment. These activities compacted most available soil on the property. Poor receiving soils and limited areas for a new system dictated the need for a treatment solution that would provide high-quality effluent in a small footprint. A replacement conventional stone-and-pipe system would not fit in the area.

Solution: The Eljen team, along with Kansas Environmental Health Association, used the site for training and an installation demonstration. Bob Blasi of Adams Electric & Plumbing did the design and installation of an above-grade 450-gpd system on heavy clay soils. The system contains 36 A42 GSF (Geotextile Sand Filter) units in two laterals and is center-fed. The pump-to-gravity system has a distribution box in the middle of the two rows.

Result: The versatility of the GSF units allowed the designer to choose an in-ground or above-grade system, as well as work the layout suitable for the limited site. The repair system was raised and protected from maintenance vehicle traffic and parking. The smaller-treatment raised system was able to fit in the available space. 800-444-1359;

Treatment system used to standard flow within limits

Problem: Registered sanitarian Jon Maass of JMI OSSF Consulting was contracted to help with a challenging mixed-use site of a 300-plus-people office complex, culinary training facility with corporate housing/condos for trainees in Dripping Springs, Texas. When all the uses of the property were added up, they were looking at 5,400 gpd flow on weekdays, with just the condos on the weekends at 2,700 gpd. In Texas, systems discharging more than 5,000 gpd aren’t permitted at the local level under TAC 285. State permits can take in upward of a year to obtain and at much greater expense in both equipment and permit/design fees, and this site was well under construction and expected to be occupied within six months. 

Solution: Working with the sanitarian, Hoot Systems was able to devise a plan to provide additional flow equalization and stack the excess waste generated Monday through Friday, adding this to the weekend flows to utilize the whole week’s capacity limits. The flows from the condos were residential strength, however the office building and training kitchen generate higher strength waste. This combined flow required a 12,500 gpd MTS treatment system to properly treat the waste stream.

Result: Technicians from Hill Country Wastewater were able to get the system installed on budget and in time for the grand opening, and are the current operators. The daily flow to the drainfield has kept at or below 4,800 gpd, and is in compliance with the TAC 285. 888-878-4668;

System provides solution for Camp Fire emergency housing

Problem: The 2018 Camp Fire devastated the community of Paradise, California, killing 85 people, destroying 11,000 homes and displacing nearly 50,000 people. The Federal Emergency Management Agency needed to stabilize the situation and support rehabilitation of the community. This required a 1,500-worker camp, which included 400 temporary housing units, laundromat, and food preparation and dining facilities. Complications included accelerated deadlines and extreme site limitations, including shallow lava formations, which impeded construction and precluded subsurface dispersal.

Solution: A General Order Permit was acquired to speed development. A 100,000-gpd Advanced Enviro-Septic wastewater treatment system from Presby Environmental was selected, and specialized equipment was employed to excavate through solid lava-rock. The system receives gravity-flow influent to four 40,000-gallon septic tanks configured in series. The effluent is then segregated into four treatment paths to facilitate isolation during maintenance. The flow is split to four lined AES beds performing passive secondary treatment. Each 25,000-gpd bed contains 8,400 feet of AES pipe surrounded by specified sand for a total 33,600 feet of AES pipe. Treated effluent is collected and gravity-distributed to four UV disinfection units, each followed by a pump tank. These pumps distribute purified effluent to two evapotranspiration ponds, which allow for possible reuse.

Result: The low-maintenance, high-flow system, including disinfection, allows for full occupancy of the worker camp. This provides needed resources close to the devastated community. 603-837-3826;


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