Sustainable management of municipal wastewater reverse osmosis concentrate: treatment with biological activated carbon based processes for safe disposal

Reverse osmosis concentrate (ROC) streams generated from RO-based municipal wastewater reclamation processes pose environmental and health risks on their disposal to sensitive water environments. Management of the ROC remains a big economic and technological challenge for the water industry to sustain the practice of water recycling. This paper presents some recent investigations into the effectiveness of biological activated carbon (BAC) process, as a potentially cost-effective and environmentally-benign treatment option, for removing organic matter and nutrients (N and P) from the ROC and reducing its toxicity. The impact of ROC characteristics and pre-treatment options including advanced oxidation (UV/H2O2) and chemical coagulation (FeCl3) on the treatment efficiency is discussed. Further information about bacterial communities in the BAC system is provided for a better understanding of the effectiveness and robustness of the BAC system at different salinity levels. Overall, BAC-based processes have been demonstrated as a resilient treatment for reducing the environmental risks associated with municipal wastewater ROC.