Jennie-O Turkey Store owns and operates a 0.057 m3/sec (1.3 MGD) treatment plant for treating wastewater from the slaughter of 26,000 turkeys per day. In 2000, Jennie-O Turkey Store was required by the Wisconsin Department of Natural Resources (WDNR) to remove phosphorous below 1 mg/l. The existing lagoon system with seepage cell was not removing phosphorous cost effectively and odors were a continuing issue. To improve the plant’s waste treatment process, an activated sludge system was proposed to replace the lagoon system.
After screening and pumping at the existing slaughter facility, wastewater flows to an equalization basin, and then receives primary treatment through dissolved air flotation (DAF), using ferric sulfate and anionic polymer as flocculants. The DAF effluent is then further treated in an Orbal oxidation ditch for complete nitrification, phosphorus removed with ferric sulfate, alkalinity controlled with magnesium hydroxide, clarified and UV disinfected. The waste activated sludge is DAF thickened in a second DAF tank using a cationic polymer and joins the primary DAF float sludge in sludge storage. Sludge in the storage tanks is mixed 3-times per year and liquid hauled to land application. During the year, decant from the sludge holding tanks is pumped to the waste activated sludge DAF unit for solids removal and the underflow goes to the oxidation ditch. The new activated sludge system came on-line in June 2002.
This paper presents the results of a comprehensive and innovative evaluation to overcome a persistent filamentous bulking problem in an industrial waste treatment facility. Specifically, it will reveal how a multi-ring oxidation ditch was modified, with minor construction changes, to provide selector benefits in treating highly soluble BOD wastewater. Actual data from startup through three years of operation will show the impact of a selector on activated sludge settling and control of filament O21N. The paper disproves, at least in this specific case, the theory that a selector effect occurs in the outer ring of such ditches due to alternating aerobic and anoxic conditions. In actuality, introducing the wastewater to the outer ring of this ditch helped propagate the growth of filament O21N, likely due to rapid dispersion of the soluble waste throughout the ring volume. In contrast, introducing the wastewater to the inner ring of the ditch and reversing the flow through the ditch has shown to significantly control the growth of filament O21N and has provided a simple, easy to operate, and very cost-effective solution to the filamentous bulking problems.
Jennie-O Turkey Store has a 26,000 turkey per day slaughter/packaging facility in Barron, Wisconsin. The wastewater from this facility is treated in a 0.057 m3/sec (1.3 MGD) treatment plant, owned and operated by Jennie-O Turkey Store, with treated effluent discharged to the Yellow River.
In 2000, Jennie-O Turkey Store was required by the Wisconsin Department of Natural Resources (WDNR) to remove phosphorous from its wastewater, implementing an effluent concentration limit of 1 mg/l. The existing treatment system, consisting of equalization followed by dissolved air flotation (DAF) primary treatment (using ferric sulfate and anionic polymer) and an aerated lagoon system with a seepage cell was not able to achieve these new phosphorus limits costeffectively. Coupled with ongoing odor problems, Jennie-O Turkey Store and its consultants, Donohue & Associates and Cedar Corporation, developed a plan to replace the lagoon system with an activated sludge system.
The new treatment train begins at the slaughter waste facility, where the wastewater is screened and pumped to the treatment plant. The first steps of treatment were not changed – the wastewater flows to an equalization basin and then receives DAF primary treatment using ferric sulfate and anionic polymer as flocculants. The DAF effluent then flows to the new activated sludge facilities, consisting of an Orbal oxidation ditch followed by secondary clarification. The secondary effluent flows through a new ultraviolet (UV) disinfection system prior to discharge to the Yellow River. The process flow diagram is show in Figure 1.
The activated sludge system, which came online in June 2002, was designed for complete nitrification year-round, and for chemical phosphorus removal via ferric sulfate addition. The system includes supplemental alkalinity addition using magnesium hydroxide. The waste activated sludge (WAS) is DAF thickened in a second DAF tank, using a cationic polymer, and is then sent, along with the primary treatment DAF float sludge, to sludge storage. Sludge in the storage tanks is mixed 3-times per year and liquid hauled to agricultural land application sites. During the year, decant from the sludge holding tanks is pumped to the waste activated sludge DAF unit for solids removal and the underflow goes to the oxidation ditch.