Animal Farming and Slaughterhouse Wastewater Treatment

Animal Farming and Slaughterhouse Wastewater Treatment

Wastewater treatment of animal farming and slaughterhouses (cattle, sheep, and poultry) is of great importance due to high levels of suspended solids, organics and ammonia. Nitrogen and phosphorus present in wastewater, if infiltrating into surface and groundwater, have negative impacts such as eutrophication of water bodies. The mean amount of different parameters are as followings:

Pollutant

Mean (mg/l)

SS (mg/l)

20,000

BOD (mg/l)

5,000

COD (mg/l)

20,000

TKN (mg/l)

900

TP

200

Wastewater quality or quantity varies depending on operating units and location of water use. The main water usage depending on the manure collection method:

Dry collection of manures

  • Drinking water
  • Washing of milking machine
  • Wet spray
  • Washing of maternity place and equipment

Wet collection of manures

  • Drinking water
  • Washing of milking machine
  • Wet spray
  • Washing of maternity place and equipment
  • Washing of resting place

The water used for washing milking machine, maternity equipment and resting place are turned into wastewater. In wet collection of manures, wastewater has higher quantity with higher levels of pollutants.

The type of treatment process depends on the quality of wastewater. For example, washing milking machine by chemicals (hydrochloric acid) will affect the final wastewater characteristics.

Process Design for wastewater treatment

The main units for wastewater treatment are as follows:

  • Screens (manual and mechanical)
  • Grit chamber and oil separator
  • Equalizer
  • Primary settling
  • Anaerobic treatment (anaerobic lagoon, UASB, UABR,…)
  • Aerobic treatment (suspended or attached growth, MBR, MBBR,…)
  • Secondary settling
  • Clarifier lagoon
  • Rack filter
  • Chlorination
  • Effluent storage tank

Depending on the quality and quantity of wastewater, some of these units may be removed. The wastewater treatment of industrial slaughterhouses can be implemented with the same process, with the difference that the daily slaughtered body changes the quality of the wastewater. In such cases, because of high pollutant levels, all parameters should be considered.

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