Treatment of Slaughterhouse water

8/14/2019 Treatment of Slaughterhouse water

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Treatment ofSlaughterhouse

WastewaterMike Lawrence

NDSUFall 2006


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Overview

Challenges

Wastewater Parameters

Treatment OptionsProcess Modifications

Typical On-site Treatment Options

Design Problem


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Challenges of SlaughterhouseWastewater

Wastewater contains large amountsof blood, fat, and hair

Wastewater is above municipalstandards which leaves two options;on site treatment or pay to betreated elsewhere

On site treatment with low capitaland maintenance costs is desirable


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Wastewater Parameters

BOD approx. 1,000 to 4,000 mg/L

COD approx. 2,000 to 10,000 mg/L

SS approx. 200 to 1,500 mg/LHigh Oil and Grease content

Possible high chloride content from

salting skins


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Treatment Options

Discharge to sewer to be treated bymunicipal treatment plant

Land application of wastewater forirrigation

Reduce amount of wastewater and/orconcentrations with the wastewater bychanging the processes

On site Treatment Flow Equalization, Screening, Dissolved Air

Flotation, Primary Sedimentation

Aerobic Treatment

Anaerobic Treatment


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In-Plant Modifications to ReducePollution

Main goal should be to prevent productfrom entering the waste stream and usingthe least amount of water possible

Reduce the amount of water used, savesmoney in two ways

Use high pressure and just enough

Proper detergents Lower volume of water helps equipment

Reuse as much water as possible


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Line Separation

Separating the various wastestreams as much as possible

Sanitary lines should be dischargeddirectly to the city sewer

Grease waste streams and nongrease waste streams can helpreduce treatment costs

Separate Blood line


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Blood Recovery

Blood has ultimate BOD of 405,000 mg/L

One head of cattle contains 49 lbs. ofblood which equals 10 lbs. BOD, compared

to 0.2 lbs. discharged per person per day All blood should be recovered in a

separate line draining to a tank

Blood is then dried, commonly acontinuous drier is used

Profitable end product


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Stockpen Area

Stockpen waste and other manureshould be hauled away as a solid

Cleaned periodically with as littlewater as possible

Ideally this water would go to aseparate tank

From the tank it would be emptiedinto a truck and land applied


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On-Site Treatment

Costs of treating on site or lettingthe municipality treat the wasteshould calculated

Maintenance and operation should bealso put into cost analysis

Flow equalization is usually a verygood first step in on-site treatment


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Hydrasieve

BOD Removal 5-20%

TSS Removal 5-30%


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Hydrasieve

Width(ft)

Height(ft)

Capacity(gpm)

EstimatedPrice

2 5 75 $5,200

3.5 5 150 $6,400

4.5 7 300 $8,000

5.5 7 400 $10,000

6.5 7 500 $12,000

7 7.3 1000 $20,000

14 7.3 2000 $40,000

21 7.3 3000 $60,000

28 7.3 4000 $80,000

35 7.3 5000 $100,000


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SS and Grease Removal

Grease removal could be veryprofitable

Skimming operations

20 to 30 % BOD removal

40 to 50 % SS removal

50 to 60 % grease removal

Dissolved Air Flotation, DAF30 to 35 % BOD removal

60 % SS removal

80 % grease removal


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Skimming Operation (PrimarySedimentation)

Detention time 1.5 to 2.5 hr

Overflow Rate 800 to 1200 gal/ft2*d


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Dissolved Air Flotation (DAF)

Hydraulic Loading Rate 1.5 to 5.0 gpm/ sq. ft.

Solids Removal Rate 1.0 to 2.0 lbs/hr/sq. ft.


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Anaerobic Lagoons

Ideally the lagoon would be covered, odor &gas production contained, heat retention

Not well suited for colder climates

Detention time 20 to 50 days BOD5 loading= 200 to 500 lb/ac.-d


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Anaerobic Contact Reactor (ACR)

Hydraulic Retention time 0.5-5 days

Organic Loading rate of 1.0-8.0 kgCOD/m3-d

Flocculator or


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Anaerobic Sequencing BatchReactor (ASBR)

HRT 6 to 24 hours

SRT 50 to 200 days

98% removal with

1.2kgCOD/m3

-d 92% removal with

2.4kgCOD/m3-d

Possibly rates to

5 kgCOD/m3-d Effluent SS range

between 50 100mg/Ldepending on HRT


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Upflow Anaerobic Sludge Blanket(UASB)

Proteins and fatsmay cause problemsin formation of

granules. Loading rates of

4-12 kg sCOD/m3-d

Retention times of7-14 hours


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Design Problem

Flowrate:120,000 gpd, 83 gpm, Max300 gpm

TSS=1500 mg/L

COD=5000 mg/L

sCOD=3000 mg/L

BOD5=2,000 mg/LReduce levels to municipal levels and

discharge into sewer


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Screening

Hydrasieve

Use prior to flow equalization to saveon pumps and buildup in the tanks

Design for max flow of 300 gpm

4.5 by 7 foot model will handle flow

Approximate cost of $8,000


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Primary

Loading Rate of 600 gal/ft2-d

Final Design

8 ft. wide, 25 ft. long, 10 ft. deep

8 ft. of weir w/ loading rate of 15,000gpd/ft

HRT = 3 hours

25 ft

10 ft

8 ft


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Anaerobic Lagoon

Covered for heat retentionSide depth = 8 feet

Final Design 540 lb BOD5/ac-d

HRT=80 days Plan View

400 ft

400 ft


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Anaerobic Contact Reactor

Final Design HRT=5 days

Loading Rate 1.0 kg COD/m3-d

Clarifier design based on 24m/dsettling velocity

30 ft

56 ft

10 ft

16ft

ClarifierAnaerobic Contact Reactor,Completely Mixed

Flocculator,Deglassifier


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Aerated Sequencing Batch Reactor

Two reactors of same size Feed 8 hr, react 37.5 hr, settle 2 hr,

drain .5 hr

Feed 8 hr, react 13.5 hr, settle 2 hr,drain .5 hr

46 ft

24 ft

Sludge waste

at bottom

Supernatant Drain 11.5ft above bottom


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Upflow Aerated Sludge BlanketReactor

Loading Rate of 10 kg sCOD/m3-d

Two tanks, operated in parallel

Diameter = 4.5 m, Height= 7 m,

2.5 m for gas storage

7 m

4.5 m


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Final Design

Include Hydrasieve: effectiveness andlow capital, O & M costs

Upflow Anaerobic Sludge BlanketReactor

Tank is smaller than most of the othersdue to high organic loading rate

Provides constant source of methanegas

Treatment of Slaughterhouse water

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