Eugene/Springfield Water Pollution Control Facility 1984-1991

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Page 38 Section E: RESIDUALS MANAGBMENT FACIIdTIBS OPERATIONS • Well Water Irrigation The first year fescue grass seedlings were too small and delicate to tolerate the low pH cannery efflu- ent. Toensure the sensitive plants survived, irriga- tion water was drawn from a well and pumped to the aeration basin, where it was withdrawn by the irrigation pumps. This was the first use of the center pivot irrigation equipment. • Programmable Controller The design of the irrigation system included pro- grammable logic controllers to operate the four center pivot irrigation units. During start-up, a problem with the original programming was dis- covered.The four center pivots would only operate sequentially. A pivot would make one pass across the field then have to shut down before another pivot could start up. This resulted in excessive startingandstoppingof thepivots, irrigationpumps, and other related equipment. The crops needed to be irrigated with larger quantities of water over longer periods of time to allow the water to perme- ate through the soil to the roots. The controller was reprogrammed to reduce the cycling of equip- ment. • Chlorination The facility was equipped with chlorination equip- ment that used one-ton tanks of chlorine to con- trol the odors from waste flow irrigation. The operations staff tested the system during the start- up season and concluded it could not be used continuously. They found that applying chlorine did not produce a noticeable reduction of odors during irrigation, even when higher rates were applied. Also, using large amounts of chlorine was likely to produce organic halogen compounds, formed by the chemical reactions of chlorine and organic compounds. (Organic halogens are unde- sirable because some, such as trihalomerhane, are carcinogens.) Staff found that well-planned waste handling and irrigation practices were more effi- cient and reliable than chemicals in controlling odors. • Pump Station Instrumentation Other problems with the new equipment were not so easily identified and required persistence and methodical problem solving to resolve. For ex- ample, one incident involved an alarm at the Agripac pump station. Operators would receive frequent alarms that a wet well was ovelflowing, but when checked, the well would be operating at a normal level. Staff finally found the problem was in the sonic level sensing device. The waste enter- ing the tank would produce a surface foam that absorbed the sonic waves instead of reflecting them to the water level sensing device. The water would rise until the tank overflowed, carrying off enough foam for the sensing device to receive the signal to start the pumps. Everything would be back to normal by the time an operator arrived. The sonic level detector was eventually replaced with a combination of bubble tube and float-ball level detectors. MAJOR PROJECTS, EVENTS, AND INCIDENTS OnJuly3,1984, thefirstcannerywastewaspumped into the storage lagoon. The following month, the irrigation system was operational and the CWMF began irrigating well water onto grass seedlings. Cannery effluent was irrigated for the first time in September 1984. Some of the problems and im- provements made since that time are as follows: • Center Pivot Field Ruts The center pivot wheels of the irrigation system caused a problem when they cut deep ruts into the fields where they tracked. In some locations, the ruts were nearly two feet deep. At about two feet, the centerpivot would bottom out and fail. Before beginning the second year of operation, the ruts were filled with hog fuel or straw. Staff found that, although straw was less expensive, it could not support the pivots and did not work in wet field conditions. Hog fuel has continued to be used as a filler when ruts develop. Now that a firm soil base hasbeenestablished,the amountof hogfuelneeded is less each season. • Preventive Maintenance Program In November 1985, staff implemented a preven- tive maintenance program for the CWMF. Equip- ment that needed preventive maintenance .was identified and labeled. Preventive maintenance tasks were documented by description and fre- quencyandimplementedinto theregionalfacility's preventive maintenance program. • Storage Lagoon Leak Tests The storage lagoon has successfully passed each of the annual leak tests required by the permit. With over six years of operation without a leak, we expect the renewed discharge permit to reduce the