Intensive pig farming produces large volumes of high strength waste streams that need to be treated before being discharged to the environment. The traditional management practise consists of the pig manure and urine being flushed into open-air lagoons for biological degradation before being discharged or applied to adjacent cropland.

The major shortcomings of this practise are;

  • Open-air lagoons are usually not aerated causing the formation of anaerobic conditions. The resulting discharge of Methane, a potent greenhouse gas, Hydrogen Sulphide and Ammonia to the atmosphere contribute to climate change, poor living environment for surrounding communities from the animal odours emitted, and contribute to acid rain.
  • Intensive pig farms are increasing in size to take advantage of economies of scale in a bid to remain competitive. The supply of pasture land able to receive the nutrient rich discharge from the lagoon system is limited while seasonal variations may mean that crops are not cultivated year round. The expense of transporting the nutrient rich discharge then becomes a significant cost factor.


When properly managed, manure can be used as a nutrient source for crops and to improve soil properties through increase of soil organic matter. On the other hand, improperly managed manure can pose a threat to soil, water and air quality, and to human and animal health.


Selectra’s solution is to deploy the H2E anaerobic digester developed by EKO GEA. System advantages are;

  • Effluent discharge that meets Irrigation Discharge Standard requirements High process efficiency – 90% destruction of organic loading.
    • Ion exchange limits the discharge of Ammonia and Hydrogen Sulphide
    • Pathogens are largely destroyed by anaerobic digestion.
    • Treated water can be recycled for general plant use, or upgraded to SANS 241 potable water through the use of additional technologies, thereby saving on water costs
    • Discharge to municipal system does not incur surcharges for not meeting specification.


  • Reduced CAPEX Cost
    • Hydraulic Retention Time of 10 days of less, depending on feedstock type.
    • Smaller footprint, usually 1/3rd the size of conventional AD systems, resulting in capital cost reduction.


  • Reduced OPEX Cost
    • Biogas energy use reduces operating cost allowing a system payback of approximately 5 years.
    • High system efficiency results in high energy yield More organics treated (at least 90% destruction of organics) combined with high methane content biogas (typical methane content of 65-80%) results in a superior energy yield.
    • Plant requires low parasitic load thereby allowing for greater energy export



  • Little or no organic sludge Mineral sludge has high value and is an effective nutrient recovery system


  • Unsurpassed process stability with the addition of Biocomplex bio-activator Enhanced biological reaction that improves biological wastewater processes
    • Greatly increases bacterial metabolic rate by supplying essential nutrients and trace elements
    • Improves the ability to handle shock loads as microbes have less die-off in their restive state
    • Improves bacterial breakdown of organic material as microbe activity is enhanced.

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