ENVIRONMENT
Ruminant animals release methane as a by-product of digestion. This process is called enteric fermentation. In South Africa, agriculture accounts for about 9-10% of greenhouse gas emissions, of which 60% is derived from methane in enteric fermentation of livestock and game farming. The dairy industry accounts for only about 10% of the methane emissions in South Africa owing to the comparatively small scale of the industry. Research into the use of this methane for energy production and the reduction of methane emissions by the dairy sector is ongoing
The South African dairy industry has employed several strategies to manage wastewater efficiently, focusing on reduction, recovery, recycling, and treatment to minimise environmental impact and improve water sustainability.
1 Reducing water use
- Many dairy processors optimise clean-in-place systems to minimise water wastage.
- Staff training and awareness programmes help reduce unnecessary water use during processing.
- Efficient batch sequencing ensures rinse water is reused where possible.
2 Wastewater recovery and reuse
- Some facilities recover wastewater for non-potable applications, such as cleaning and cooling.
- Reverse osmosis technology is used in advanced setups to treat wastewater and convert it to potable standards for reuse in processing.
- Effluent pre-treatment helps remove solids and contaminants before wastewater is discharged or reused.
3. Effluent treatment and energy recovery
- Dairy effluent is treated using methods such as anaerobic digestion, bioreactors and filtration to remove organic material and pollutants.
- Anaerobic bioreactors convert organic waste into methane gas, which is then used as an energy source at dairy plants.
- Effluent is processed to meet environmental regulations before being discharged into municipal systems or natural water bodies.
4 Case Study: Woodlands Dairy
- Implemented an integrated water and waste recovery system owing to limited municipal wastewater treatment capacity.
- Reverse osmosis is used to treat wastewater to potable standards for factory use.
- An anaerobic bioreactor captures methane from organic waste, which is then used to fuel boilers. This reduces reliance on external energy sources.
By implementing these measures, the dairy industry enhances water efficiency, reduces its environmental footprint and ensures sustainable water use throughout the supply chain.
Dairy farming contributes about 10% of greenhouse gas emissions from all cattle in South Africa, amounting to approximately 3.72 metric tones CO2 equivalent per year. This is a relatively modest contribution compared with that of the total agricultural sector. Moreover, improved breeding and feeding practices and increased productivity per cow have significantly reduced emissions per unit of milk produced.
Methane emissions are being reduced through better breeding and feeding practices, which improve feed conversion efficiency. Research is also exploring alternative approaches, such as using legumes to reduce methane production and adjusting diet compositions to enhance digestion. Precision feeding has also shown promise in minimising enteric fermentation emissions.
Carbon sequestration in soils is a powerful tool for reducing net emissions. Practices like no-till farming, multispecies pastures, organic manure application and rotational grazing significantly enhance organic carbon levels in soil. For instance, minimum tillage practices in South Africa have increased soil carbon stocks by up to 50%, helping to offset emissions from dairy farming.
Studies show that excessive nitrogen application is often unnecessary. In many cases, applying 150–200 kg N/ha annually is sufficient to sustain productivity. Natural nitrogen fixation by legumes and cycling through manure can meet plant needs, reducing reliance on chemical fertilisers and limited nitrous oxide emissions.
Pasture-based systems improve sustainability by adopting conservation agriculture, implementing rotational grazing and using multispecies pastures. These practices enhance efficient nitrogen use, reduce greenhouse gas emissions and boost milk production per hectare. They also protect soil health and biodiversity, showcasing that pasture-based farming can be both efficient and eco-friendly