Municipal WW

The treatment solution for waste activated sludge

Secondary, waste activated sludge (WAS) is a waste product generated in large quantities at wastewater treatment plants (WWTPs) globally.

WAS is a difficult waste as it is not readily degradable when landspread or via anaerobic digestion (AD), especially when compared to primary sludge. Land spreading practices are increasingly restricted, but to generate sustainable levels of renewable biogas from WAS, it must be pre-treated to ‘unlock’ the organics within.

The solid fraction of WAS is a complex mixture of organic material and micro-organisms held together by extracellular polymeric substances (EPS). The complex structure of the material makes it resistant to degradation by microbes in AD and therefore gas yields are poor.

Biowave™ pre-treatment solubilises COD, disrupts the EPS structure and the cell walls of the WAS micro-organisms. The increased availability of the organic matter leads to improved gas yields in AD.

Biowave™ is a modular, flexible solution for the pre-treatment of WAS for AD, and can be scaled to suit small, local WWTPs or larger facilities. It is an energy efficient process versus conventional thermal treatment methods. Using Biowave™ to pre-treat WAS avoids disposal costs as well as increasing renewable gas production.


Solubilisation of complex WAS material

Improved gas yield in AD of WAS

Higher throughput into AD

Flexible, modular solution

Common Questions

Waste Activated Sludge (WAS) is a complex mixture of microbial biomass, dissolved organic and inorganic substances and
solids. The microbial biomass is interlinked by extra-cellular polymeric substances (EPS). Along with
the microbial cell wall structure, these EPS make it difficult for anaerobic microbes to access the
organic substrate within for conversion to biomethane gas. As a result, much of the organic content
of WAS is left untouched after AE and the energy potential of the material is not realized. For this
reason, WAS is often disposed of via landfill or incineration.

Biowave™ pre-treatment enhances the breakdown of EPS and disrupts cell wall structures, releasing
the organic contents of the cells to solution and making them available to microbes in AD. This is
seen as a decrease in the total solids content of the substrate.