Large-Scale and Commercial Onsite Treatment Systems

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Residential membrane bioreactor

Problem

Alternative Wastewater Systems in Caldwell, Idaho, wanted to test the BioBarrier membrane bioreactor from Bio-Microbics in a residential installation. Ryan Spiers of Spiers Construction in Caldwell identified a new four-bedroom home as part of a community collection system discharging to an evaporation pond. He asked the homeowners if they would upgrade from a MicroFAST 0.5, also from Bio-Microbics, to the 500 gpd bioreactor at no cost. They agreed.

 

Solution

The 60-pound unit, installed in a precast septic tank, replaced an aerobic treatment unit. The bioreactor’s flat sheet membranes in a double-plate configuration provides high surface treatment while acting as a physical barrier for most water pollutants. Effluent moves through the pores to the space between the films, and a pump then discharges it. The system requires no backwash. “The bioreactor sits in black water and produces permeate that looks like store-bought bottled water,” says Spiers.

 

Result

The installation was the first of its kind in the state to evaluate membrane treatment for a single-family home. The NSF/ANSI STD 40/245-certified system was tested every other month. Direct discharge effluent samples averaged less than 2 mg/l BOD and TSS, less than 1 mg/l ammonia, and less than 10 E. coli colonies per 100 ml. The system received the 2009 Technology Award from the Environmental Business Journal. 800/753-3278; www.biomicrobics.com.

 

Solution for rural fishing village

Problem

Failing onsite systems in the rural fishing village of Victoria, Prince Edward Island, were discharging into the harbor. Provincial regulators would not approve new development or business expansion until the village solved its sanitation problem.

Since the lots were too small for conventional systems, Kelly Galloway, P.E., from Engineering Technologies Canada in Stratford, looked for a cost-effective compact solution that would recharge the island’s groundwater and accommodate hydraulic variations during the tourist season.

 

Solution

Galloway chose an effluent sewer and AdvanTex AX100 treatment system from Orenco Systems to service 57 homes and six commercial sites with effluent gravity and effluent pumping equipment. An interceptor tank at each property acts like a septic tank, only the anaerobic biological processes consume the solids. Residential tanks require pumpouts every 10 years or more, and larger tanks even less frequently.

The 10 5,000-gpd pre-engineered treatment pods have an absorbent nonwoven textile media that produces effluent clean enough for the pressure-dosed sand bed and drip irrigation fields. The sand filter works year-round and the drip system during the tourist season.

The 16- by 8- by 3.5-foot pods install and service easily, have telemetry monitoring, and draw 3 kWh per 1,000 gallons. In summer, the system uses all 10 units to treat 25,000 to more than 50,000 gpd. In winter, it uses three pods and two pumps, conserving energy and extending equipment life. The site has room for five more pods.

 

Result

Effluent averages less than 6 mg/l BOD5 and TSS. A part-time operator monitors the system remotely. Galloway won the 2009 Engineers PEI Award for Engineering Achievement, and Victoria earned the 2010 Municipal Achievement Award from the Federation of PEI Municipalities and the 2011 Sustainable Community Award from the Confederation of Canadian Municipalities. 800/348-9843; www.orenco.com/systems.

 

Attached growth anaerobic and aerobic treatment

Problem

Sewage from failed onsite systems in a 1970s subdivision in central Kentucky backed into homes or surfaced in yards. Small lot sizes and shallow clayey soils, high water tables, and rock depths made replacing the systems difficult, as did landscaping, pools, and outbuildings. The health inspector and installing contractor decided advanced treatment systems with drip irrigation would provide the best long-term solution.

 

Solution

They chose the Fusion ZF-450 treatment system from Clarus Environmental. The pre-engineered, fully assembled unit has four chambers. In the first, microorganisms on a fixed spherical-skeleton type filter create a high-performance septic tank.

Anaerobic treatment occurs at the same time suspended solids are captured. The floating and circulating chamber has an upper aeration section and a lower suspended media section. The compartment is filled with hollow cylindrical media on which bacterial colonies grow. Biological aeration treatment is continuous, while the filter captures residual suspended solids.

Because sludges develop rapidly in the third chamber, the filter is backwashed for five or 10 minutes twice daily. Air vigorously stirs the media to break up accumulated materials. An airlift pump transfers wastes back to the first chamber for further digestion and to aid in nitrification. The fourth chamber temporarily stores treated water leaving the floating and circulating chamber before discharging to a dose tank for dispersal.

 

Result

Effluent averages 9 mg/l CBOD5 and TSS. Since the system was installed, no surfacing sewage has been observed. Property disturbance was minimal due to the compact treatment units and installation of the drip tubing with a vibratory plow. Energy cost is about $4 per month with the programmable linear air diaphragm blower. 877/244-9340, www.clarusenvironmental.com.

 

Clogging problem eliminated

Problem

The wastewater treatment plant at the Oak Hill Estates mobile home court in Holly, Mich., transfers sewage from an equalization tank to a batch reactor. The pump was consistently clogging and the motor overheated and failed twice. There was potential for the tank to overflow. Highland Treatment, the court’s contractor, performed extensive maintenance to keep the pump running. They contacted a Crane Pumps & Systems distributor, Jett Pump & Valve, to provide a rental while the pump was being repaired.

 

Solution

Jett Pump & Valve recommended replacing the pump with a Barnes SH pump based on its success in a lift station in a nearby community. A 4SHV nonclog 7.5 hp pump with vortex impeller was installed. The slotted discharge flange allowed the pump to be installed to the existing discharge piping with no modifications. The pump allows 3-inch solids handling capability and handles stringy solids at low flows. The volute allows the impeller to form a vortex that passes 98 percent of the solids without directly contacting the impeller. The impeller resists clogging from stringy and other difficult solids.

 

Result

The pump has not clogged since installation. Elimination of service calls and maintenance during inclement weather has meant significant cost savings and a safer work environment. Operations supervisor Mark Dowson calls it “maintenance free.” 937/778-8947; www.cranepumps.com.

 

Solution for 27-acre campground

Problem

The Department of Environment told the owner of Crystal Beach Campground on Prince Edward Island to replace his lagoon system in one month. The campground, on Malpeque Bay and next to a protected wetland, has 250 campsites, cottages, a swimming pool, recreation center and laundry.

The owner worked with Ken Reardon, director of business development for Atlantic Purification Systems Ltd. (APS), a distributor of wastewater products in Dartmouth, Nova Scotia. The governing jurisdiction allowed a tank-to-drainfield design, but Reardon was concerned about the structural integrity of the shimmed or multiseamed tanks available in Atlantic Canada.

 

Solution

The pair chose ZCL Composites, a Canadian manufacturer and parent to Xerxes Corp., to supply a 20,000-gallon fiberglass tank. The owner believed the excavation for and pouring of a cast-in-place tank would be too disruptive to campers.

APS manufactured the tank to order and delivered it quickly. The lightweight tank was easy to ship and install. Because of the high water table and buoyancy factor, workers secured it to concrete deadmen with straps and turnbuckles.

 

Result

The septic tank is protecting the sensitive waters and the campers’ health. 800/661-8265; www.zcl.com or www.xerxes.com.

 

Recirculation biotower

Problem

Auberge du Portage, a seasonal inn and health spa in Notre-Dame-du-Portage, Québec, has 46 rooms, a 120-seat restaurant, 15 massage suites, six showers, and a laundry with three washing machines. Effluent from the overloaded drainfield polluted the St. Lawrence River. Replacement technology had to fit in a limited space, treat high-strength wastewater, adjust to hydraulic variations, and work in difficult soils with shallow depth to bedrock.

 

Solution

Engineers selected the Segflo recirculation biotower and Ecoflex polishing process from Premier Tech Aqua. The treatment train included a grease trap, septic tank, dose tank, biotower, nitrogen removal, UV disinfection, and discharge to the river. The restaurant generated 4,400 gpd and the inn 10,100 gpd.

The biotower has snowflake-shaped PVC media to provide a large surface area for bacteria. Passive and natural oxygenation occur through water trickling from the top of the tower to the bottom, then pumped back up to the top. Recirculation also eliminates odors. Sloughed off excess biomass accumulating at the base of the tower is pumped periodically to the septic tank. The modular Ecoflex system removes nitrogen, adapts to seasonal use, and is easy to operate and maintain.

 

Result

Effluent samples have less than 10 mg/l CBOD5 and TSS with less than 10 E. coli colonies per 100 ml, better than the wastewater discharge limits to the St. Lawrence River of 30 mg/l CBOD5 and TSS. 418/867-8883; www.premiertechaqua.com.



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