The link between sludge content and disposal, in South Africa, the Wastewater Sludge Guidelines promote the beneficial reuse of sludge as a key part of sustainable management. However, when sludge quality is poor, disposal becomes the only viable option.
So, what is sludge? Sludge, or biosolids, is the solid, semi-solid, or slurry residue that accumulates in sewage treatment plants as a by-product of wastewater treatment. It’s generally classified as either primary or secondary sludge.
Unlike conventional soil, sludge contains a large amount of organic matter and water, which exists in four forms:
- Interstitial water
- Capillary-bound water
- Surface-adsorbed water
- Internal water
Sludge Treatment vs. Disposal
It’s important to distinguish between sludge treatment and disposal. Sludge disposal is the final step after treatment and typically involves landfilling, incineration, use in building materials, or land application.
The volume of sludge produced by a wastewater treatment plant (WWTP) is significant, making its management a critical and often costly challenge. To run a WWTP efficiently, it is essential to either reduce the amount of sludge produced or find feasible disposal methods that balance cost and environmental impact, including CO2 emissions.
Extracting useful elements like carbon and nutrients from sludge for reuse, especially in agriculture, is one of the most promising management solutions for South Africa.
A Better Solution for Sludge Reduction
The Membrane Aerated Biofilm Reactor (MABR) offers a significant advantage, producing up to 50% less sludge than conventional activated sludge systems. In an MABR system, the biomass attaches to a spirally wound membrane surface. This results in a much lower concentration of suspended solids in the liquid, simplifying the entire process.
We provide prime solutions designed to reduce the cost of sludge disposal and chemical use. Want to hear more about our revolutionary systems? Speak to our professional staff today.


