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13~X PHOTOSYNTHETIC PERIPHYTON TREATMENT SYSTEMS Following contract termination with Hazcorp Environmental and removal of their equipment, two groundwater treatment systems were designed and installed, one in the "Old Yard" and another in the "New Yard." The two '_reatment systems were designed to facilitate growi-~ of photosynthetic periphyton (algae and bacteria). Each system consists of four series-operated 1700 gallon translucent polyethylene tanks. The domed tanks were oriented to receive maximum sunlight and spaced so that one tank did not shade another. The flat-bottomed tanks were placed on a level sand bed and an outlet surface-baffled standpipe placed in each for water level control. Tanks were connected by piping near ground. A hand-crafted air-lift pumping device was placed in bottom center of each tank. The pump barrel is a section of PVC pipe 3 inches in diameter and 30 inches in length. A helix, fashioned by threading sections of 1/2 inch diameter PVC tubing onto a steel shaft, was glued into barrel. The pump was mounted on a weighted base to maintain it in an upright position. An airline fitting passing through barrel wall to center with an upturned "elbow", was placed near bottom of the pump barrel. A Gast diaphragm air compressor, mounted in a protective shelter and fitted with a manifold and four ) air flow control valves, is used to operate pumping devices. The ....... rated air flow of the 1/8 HP compressor is 1.1 cfm. Extruded polyethylene mesh tubing 1.0 inch in diameter (Naltex) was used as media for attached growth of photosynthetic organisms. Tubing was cut into 54 inch lengths, with each tube bottom-weighted with a section of PVC pipe. Each tank was provided with 350 tube sections. I System inflow passes through a water meter and grit trap. Supplemental nutrient addition was not needed to sustain growth of photosynthetic organisms as analytical results of groundwater revealed phosphate content of 0.04-0.06 mglliter and nitrate content of 2.2-3.9 mg/liter. Excluding tank bottom area, solid surface area for attached growth provided by polyethylene tubes and tank side walls was some 3500 ft2. At design flow, daily hydraulic loading on media surface is 8.2 gal/ft2. Actual system throughput has varied with well yields. The BTEX in pumped wells fluctuates from zero to high levels. - 2 - pa1:;e 4 of 4 of xhibit A