Eugene/Springfield Water Pollution Control Facility 1984-1991

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Section E: RESIDUALS MANAGEMBNT FACILTrIES OPERATIONS Page 39 number of required leak tests from one test every year to one every five years. • Bypass Modification for Odor Control In May 1986, maintenance personnel completed a modification to control odors during broccoli pro- cessing. Abypasswas installedaround theaeration basin to allow cannery effluent to flow directly into the storage lagoon. The modification brought the broccoli waste to the subsurface of the lagoon, whichhelpeddilute itbefore itwasirrigated. Italso allowed staff to empty the aeration basin sooner and to winterize pumps, pivots, and related equip- mentearlier in the season. • Flow Meter Installations In early 1987, a new flow meter was installed to accurately measure cannery effluent. Individual flow meters also were installed at each center pivot to help staff more accurately calculate organic and hydraulic loadings. {Plant staff designed, devel- oped specifications, and installed the flow moni- toring system.) Accurate flow measurement al- lowedaprecise calculation ofwaterbalanceforthe site. All original organic and hydraulic loading calculations were based on rates established for irrigationpump capacities. Flow measurement and subsequent calculated loading rates showed that pump capacity rates did not reflect actual flow conditions. Thus, all previous records based on estimated flows were inaccurate, making past esti- mates unusable. • Lagoon Dike Inspection Several shelves had formed at various elevations on the earth dike. In June 1987, staff removed a section of the hypalon lagoon liner to inspect the dike. They discovered no evidence of leaks and decided the shelves were causedby wave action on the lagoon bank. A soil specialist inspected the dike and sugges ted itwas inadequately constructed. Although not an immediate concern, iF the condi- tionworsens,affected areas of the lagoon bank will require reinforcement. • Force Main Leaks In September 1987, a leak occurred in the force main, and another leak occurred three days later at a different location. Both leaks were caused by failing pipe joints. Although the leaks were simple to repair, it required considerable effort because staff had to track down the necessary parts. Re- placementparts are now kept in stock. • Agripac Pretreatment Modification In April 1988, the Agripac Cannery modified piping at the cannery site to allow screened efflu- ent toflow directly into the pump station wet well rather than through the clarifier. Even though this was part of the original design, until the modifica- tion, the clarifier actually received all cannery waste flow before it was sent to the pump station. Although it was effective in clarifying the waste- water, itcould not remove solids. The new piping allowed the improved clarifier operation to cap- ture more of the cannery solids and decrease the amount of solids pumped to the irrigation sites. Protective Coating of Irrigation Equipment The low pH balance of the wastewater caused deterioration of surface areas of the center pivot irrigation equipment after four seasons of irriga- tion. The original galvanized coating could not provide long-term protection against the low pH, and eventually large surface areas completely eroded.Alternativeprotective coatingswere evalu- atedfor their durability when exposed to low pH and to ultraviolet rays. An aliphatic polyurethane coating proved to be the most cost-effective, long- termprotection. Inthe summer of 1988, all center pivots were sandblasted and recoated. After two seasons of irrigation, the new coating continues Co provide corrosion protection. • Installing Dry Dirt Removal System Near the end of 1988, Agripac installed a dry dirt removal system at the cannery site. The system, which has a shaker screen that is used during carrot processing, has improved the removal of solids that otherwise would be carried to the CWMF. OUTLOOK In the next five years, the CWMF may well face its greatest challenges. Among them are the follow- ing: • Limited Available Irrigation Acreage The acreage available for irrigation at the existing site barely meets current waste disposal needs be- cause there are significantly fewer irrigation days available each year than was expected when the site was designed. Poor subsurface drainage is an- otherfactor that limits the amount of water that can be irrigated onto the site.