Envirotek Septic Solutions owner Alan Chapin digs a trench to connect a drainfield with OSCAR coils to septic tanks at a residential job site.
Washington’s Camano Island and nearby lands have many properties where shallow hardpan layers or high water tables pose challenges for onsite treatment system installers.
Alan Chapin, co-owner of Envirotek Septic Solutions, headquartered on the island, says these sites are well suited for OSCAR (Onsite Sand Coil Area Recharge) systems from Lowridge Onsite Technologies. These low-profile treatment and dispersal systems require as little as 12 inches of soil above water or a restrictive layer.
The company offers variations on the basic OSCAR platform. The OSCAR-LOWeFLOW has an extremely small footprint. It is comprised of a 6-inch layer of C-33 sand media and a series of pre-assembled Netafim Bioline drip tubing coils.
The sand media is placed on a prepared soil surface. The coils are then placed on the media and covered with another 6 inches of sand media. The sand/soil interface is the discharge point of the treated wastewater. Vertical separation is measured from the original soil surface to the restrictive layer.
The treatment system components include a gravel recirculation filter, recirculation/mixing tank, headworks, and a discharge/clarifier tank. Wastewater is collected in a standard septic tank; effluent flows to the recirculation tank where it is mixed with treated filtrate from the filter. The mixed liquid is dosed to the drip tubing network.
System design flows range from 240 gpd to 100,000 gpd. Average treatment level results after a six-month test were 5 mg/L CBOD₅, 9 mg/L TSS, 27 fecal coliform colonies/100 mL, and turbidity ranged from 1-2 NTU.
The OSCAR-II includes a treatment vessel, a pump chamber and the OSCAR dispersal unit. It is approved for use with a 1,500-gallon septic tank and requires 24 inches of soil. When used with other specified treatment vessels, in can be installed with soil depths from 12 to 18 inches
The OSCAR-III is comprised of a 12-inch layer of C-33 sand media and the drip tubing coils. The minimum-size tanks for design flows up to 500 gpd are a 1,500-gallon septic tank and a 1,000-gallon pump chamber.
Read more about Envirotek Septic Solutions in the November issue of Onsite Installer.
