full scale treatment of slaughter house and meat packing waste at

FULL SCALE TREATMENT OF SLAUGHTER HOUSE AND MEAT PACKING WASTE AT JENNIE-O TURKEY STORE, BARRON, WISCONSIN

Kenneth Sedmak,

Donohue & Associates, Inc. 3311 Weeden Creek Road

Sheboygan, WI 53081 [email protected]

Michael Gerbitz, Donohue & Associates, Inc. Thomas Asmus, Donohue & Associates, Inc.

Larry Reinke, Jennie-O Turkey Store Timothy Stockman, Cedar Corporation

ABSTRACT 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

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filament O21N and has provided a simple, easy to operate, and very cost-effective solution to the filamentous bulking problems. KEYWORDS Oxidation Ditch, Selector, Soluble Waste, Filamentous Bacteria O21N INTRODUCTION 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 cost-effectively. 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. Background 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. Flows and Loadings Wastewater flows to the treatment plant during the production cycle from the slaughter house, which typically operates 5 days per week. The design flows and loadings are shown in Table 1.

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Table 1- Flow and Loadings

Parameter Per Day Units Flow (Average) 1.2 mgd Flow (Peak ) 1.4 mgd BOD (Average) 10,000 lbs 977 mg/l BOD (Peak) 15,000 lbs 1,284 mg/l TSS 5,200 lbs 603 mg/l TKN 750 lbs 88 mg/l TP 158 lbs 16 mg/l

At the end of a production week, the slaughter house facilities are fully disinfected. This cleanup is completed by Saturday morning, and it is repeated on Sunday night before production begins for the week. Due to the long forcemain, the Saturday disinfectant wash was stored in the forcemain and entered the wastewater plant with the Sunday evening disinfectant wash. It was noted that the water quality in the activated sludge process was impaired after startup at the beginning of the production week. Activated sludge flocs were dispersed, indicating chemical attack. It was suspected that the disinfectant was breaking up the sludge floc, causing the effluent quality problems early in the week. The plant initiated a system to flush the disinfectant from the turkey processing plant to the activated sludge plant on Saturday after shutdown so that the activated sludge plant could handle the reduced disinfectant shock load on Monday morning. This process improved operation and effluent quality early in the week. Figure 2 shows the daily flow at approximately 1-1.1 MGD with weekend flows of 0.1-0.2 MGD. PERMIT REQUIREMENTS The treatment facility was required to meet a total phosphorous limit of 1 mg/l or less as calculated by a rolling average. The other permit parameters were based on daily max. and monthly averages normally calculated. As shown in Table 2, the permit requirements were changed in April of 2005 with the exception of phosphorous.

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Table 2 - Permit Requirements

Parameter Unit Day Max. (During Design)

Day Max. (New Limits

4/1/05)

Month Avg. (During Design)

Month Avg. (New Limits

4/1/05) BOD mg/l 26 26 32 16 TSS mg/l 65 30 39 20 TP mg/l 1 No change FOG mg/l 20 14 20 8 pH mg/l 6.0 - 9.0

PLANT OPERATIONS AND CHALLENGES During the initial year of operation, the facility experienced problems due to equipment and control malfunctions, and had difficulty dealing with the slaughter house waste characteristics. Dissolved oxygen control was a major issue; however, after improvements were made to the dissolved oxygen probes, dissolved oxygen control was restored. The equipment and control problems were addressed, resulting in improved facility’s operations. Dealing with the slaughter house waste proved to be more difficult, however. The characteristics for this facility’s wastewater included contributions from several challenging sources, including high soluble waste from turkey meat cooking, high soluble waste from the sludge storage decant, and disinfectants used throughout the turkey processing facility. In addition to their toxic characteristics, the disinfectants are slow to degrade and therefore can maintain a residual in the oxidation ditch. As discussed earlier, the disinfectant was flushed to the facility on Saturday to minimize the disinfectant effect on Monday and Tuesday. During initial operation of the new treatment facilities, the activated sludge process was plagued with recurring filamentous bulking conditions, resulting in high mixed liquor sludge volume indexes (SVIs), and at times elevated effluent TSS and BOD5 concentrations (see Figures 3 and 4). Mixed liquor samples were sent to Dr. David Jenkins for identification of the filamentous microorganisms predominating in the system. The dominant microorganism was identified as O21N, which often thrives under conditions of high concentrations of hydrogen sulfide, nutrient deficiency and/or readily degradable, soluble organics. These high SVI outbreaks were initially mitigated to a great extent by chlorinating the return activated sludge (RAS). However, the RAS pumps are submersible pumps, and RAS chlorination could only be accomplished by adding the chlorine to the submersible pump wet well. This proved to be a difficult method of effectively accomplishing filamentous control, and culminated in significant effluent quality impacts due to high SVIs in May and June of 2003. Concluding that RAS chlorination was not a long-term solution, an evaluation of what might be causing the growth of O21N was performed. In evaluating whether any of the typical conditions leading to O21N were present at this facility, it was determined that:

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• Sulfide levels in the oxidation ditch were low and, therefore, not a concern for the growth of O21N.

• Chemical addition of ferric sulfate to the oxidation ditch influent, for phosphorus removal, could potentially be causing nutrient (phosphorous) deficient conditions in the oxidation ditch under certain conditions. As a result, the ferric sulfate addition point was relocated to the ditch effluent overflow box, from which the mixed liquor flows to the secondary clarifier. Unfortunately changing this chemical feed point had no discernable effect on the O21N bulking occurrences, suggesting that nutrient (phosphorus) deficiency was not responsible for the O21N outbreaks.

• With sulfide and nutrient deficient conditions eliminated, elevated concentrations of readily biodegradable, soluble organics (produced from the processing of turkey meat) became the culprit for the O21N outbreaks.

DEALING WITH THE SOLUBLE ORGANICS The difficulty with having high concentrations of readily degradable, soluble organics in the waste stream of an oxidation ditch system is that these soluble organics are quickly dispersed throughout the ditch volume, similar to complete mix reactors, resulting in low bulk F/M ratios. The combination of low F/M ratios along with the presence of readily degradable, soluble organics has been reported as one cause of filaments such as O21N (Jenkins, Richard and Daigger, 2004). Under such conditions, the greater surface area of filamentous organisms, as compared to smaller, good settling bacteria (often referred to as “floc formers”), gives them a competitive advantage in terms of contacting and metabolizing the soluble substrate. Adding high F/M selector zones upstream of such tanks can overcome this problem (Jenkins, Richard and Daigger, 2004). Figure 5 shows the oxidation ditch F/M ratios and SVIs for the first year of operation. As can be seen, the ditch F/M ratio typically ranged below 0.15 lb BOD5/lb MLSS/day and the SVIs were usually above 200 ml/g (except for after RAS chlorination episodes). In the case of this facility, constructing a new selector zone upstream of the oxidation ditch was considered a measure of last resort, due to the added cost and time required for its design and construction. Alternative solutions were evaluated, including ongoing RAS chlorination or partitioning of the oxidation ditch. These evaluations concluded that RAS chlorination should only be used as a backup control method, and that overcoming the filamentous bulking condition by incorporating selector technology was preferred. However, because of the challenges in achieving effective RAS chlorination, it was decided to plan for the design and construction of incorporating the ability to chlorinate the mixed liquor as a backup for the selector technology. In evaluating selector technology, initial concepts focused on portioning the outer ring of the Orbal ditch to provide a selector volume of approximately 0.5 million gallons (MG), to achieve a selector F/M ratio in the range of 0.7-1.0 lb BOD5/lb MLVSS/day. During these evaluations, however, it was noted that the inner ring of the Orbal ditch approximately matched the desired selector volume (Table 3 shows the aeration volumes and operating parameters for the three ring ditch.)

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Table 3 - Selector Incorporation

Outer Aeration Ring Volume 1.0 million gallons Middle Aeration Ring Volume 0.72 million gallons Inner Aeration Ring Volume 0.46 million gallons System SRT 8-12 days (nitrifying activated sludge) Operating MLSS 2,000-2,500 mg/L Operating MLVSS 80% BOD Loadings 4,000-6,000 pounds (500-700 mg/l)

Fortunately the design of this oxidation ditch had provided for influent wastewater and return sludge feed points and transfer lines to the clarifier inlet pipe in each of the three rings. As a result, it was decided to change the wastewater feed and return sludge from the outermost ring to the innermost ring in an attempt to create an aerobic selector as the inner ring. Overall, the mixed liquor flow was reversed in the ditch, flowing from the inner ring to the middle, then to the outer ring and from the outer ring to the clarifier by use of the drain line and transfer pipe in the ditch (see Figure 6). The use of drain valves resulted in hydraulic limitations, but was considered acceptable for a trial period to test whether the reverse flow could provide selector benefits. RESULTS AND DISCUSSION The result of this change provided the desired control of filamentous bulking condition, with a significant improvement in mixed liquor settleability (see Figure 7). After several months of operation, the sludge volume index was controllable at approximately 100. This figure also shows the inner ring selector F/M ratio typically falling within a range of 0.5-1.0 lb BOD5/lb MLVSS/day. The selector was also evaluated by the operating staff, to assess the level of soluble BOD5 uptake within the inner ring (i.e., the “selector effect”), by sampling the inner ring effluent for soluble BOD5 concentration. This evaluation was accomplished by sampling the mixed liquor at the overflow point from the inner to the middle ring and immediately filtering it using a paper towel filter in a colander. The filtrate was then quickly transported to the laboratory, where it was again filtered using fine glass fiber filter before conducting the BOD test. Testing results indicated most of the soluble BOD5 was removed before the mixed liquor entered the second ring, with the soluble BOD5 at or below 20 mg/l leaving the first ring. The effluent quality results from June 2003, when the inner ring selector was placed into operation, through April 2004 are shown in Figures 8, 9, and 10. Some RAS chlorination was performed in October of 2003; however, after that time RAS chlorination has been minimal. Upon concluding that the inner ring would effectively function as a selector, Jennie-O Turkey Store modified the ditch by installing an effluent overflow box on the outer ring to allow the mixed liquor to flow directly from the overflow box to the clarifier. This has allowed the transfer

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pipe and its associated drain valves to be shut down, and has resolved the associated hydraulic flow restriction noted earlier. Since the selector has been in operation, the filament O21N has been controlled, sludge volume indexes are low, and effluent quality has been maintained within all permit limits. CONCLUSION From this full scale operational evaluation, it is clear that low F/M ratio with high soluble BOD can contribute significantly to the growth of O21N filament, and that under such conditions O21N can be controlled with a properly sized aerobic selector coupled with effective process control. Other plants treating wastewaters with significant readily degradable, soluble organic content and experiencing filamentous bulking problems should consider reversing the flow to achieve a similar selector effect benefit. ACKNOWLEDGEMENTS William Marten – Process Engineer, Donohue & Associates, Inc. Mark Espeseth – Operator, Jennie-O Turkey Store REFERENCES Jenkins, D; Richard, M; Daigger, G (2004) Manual on the Causes and Control of Activated

Sludge Bulking, Foaming, and Other Solids Separation Problems. CRC Press LLC: London.

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FIGURE 1 PROCESS FLOW DIAGRAM

Raw Wastewater

Pumping

Primary DAF

Decant Pumping

From Sludge Storage

Aeration Basin Settling

RAS/WAS Pumping

UV Disinfection

TWAS DAF

Flow Equalization

Sludge Storage

Ferric Sulfate Anionic Polymer

Magnesium Hydroxide/

Ferric SulfateSodium Hydroxide

Cationic Polymer

Land Application

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Influent Raw WW Flow (mgd): June 2002 - April 2004

0

0.5

1

1.5

Jun-02 Sep-02 Dec-02 Mar-03 Jun-03 Sep-03 Dec-03 Mar-04

FIGURE 2

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TSS (mg/l) / SVI (ml/l): June 2002 - June 2003

0

100200

300

400500

600

700800

900

Jun-02 Aug-02 Oct-02 Dec-02 Feb-03 Apr-03 Jun-03

TSS SVI

FIGURE 3

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BOD / TSS (mg/l): June 2002 - June 2003

0

50

100

150

200

250


TSS BOD TSS Limit BOD Limit

FIGURE 4

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FIGURE 5

F/M Ratio / SVI (ml/l) of Ditch: June 2002 - June 2003

0.00

0.10

0.20

0.30

0.40

0.50


F/M

Rat

io

050100150200250300350400450500

SVI

F/M Ratio (Ditch) SVI

Eight data points are above 500 SVI during the month of June, 2003 and are not shown

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INFLUENT WASTEWATER

RETURN SLUDGE TO CLARIFIER

MUD VALVE (TYP)

TRANSFER / DRAIN LINETRANSFER / DRAIN LINE

FIGURE 6 OXIDATION DITCH FLOW DIAGRAM

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F/M Ratio / SVI (ml/l) with Selector: June 2003 - April 2004

0

0.5

1

1.5

2

2.5

3

Jun-02 Sep-02 Dec-02 Mar-03 Jun-03 Sep-03 Dec-03 Mar-04

FM/R

atio

0

100

200

300

400

500

600

700

800

900

SVI

F/M Ratio (Selector) SVI

FIGURE 7

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Influent/Effluent Phosphorous (mg/l):July 2003 - April 2004

0

5

10

15

20

25

30


Influent Phosphorous Effluent Phosphorous

FIGURE 10

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full scale treatment of slaughter house and meat packing waste at

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