Use of reverse osmosis to modify biological wastewater treatment

ABSTRACT Introduction. The article reports on new research into improved reverse osmosis techniques and their expanded application in wastewater treatment practice. The results of experiments aimed at determining the operational characteristics of membrane facilities that treat wastewater are presented. A new method utilising reverse osmosis to decrease concentrate effluents is proposed. Flow diagrams and mass balance equations are used to demonstrate the principles underlying the new techniques. Objectives - development of reverse osmosis techniques as a novel tool for improving and modifying existing biological wastewater treatment schemes; economic evaluation of advantages in combining reverse osmosis with biological treatment processes in wastewater treatment applications; development of the required operational modes for membrane units used to treat wastewater. Materials and methods. A state-of-the-art review describes examples of the application of reverse osmosis in current wastewater treatment practices. Results of experimental research providing data for determining membrane operational parameters are presented. Analysis of results and their discussion are presented. Results. A new membrane technique that provides high product water quality and utilisation of concentrate effluents, as well as efficient removal of ammonia from reject water following sludge dewatering, is proposed. The presented results confirm the economic advantages and efficiencies of reverse osmosis applications in wastewater treatment facilities. Conclusions. The conducted investigations confirmed the high efficiency of the reverse osmosis membrane in removing all major impurities contained in wastewater following sludge digestion and during biological treatment. The use of membrane techniques thus provides efficient and reliable operation of wastewater treatment facilities. Reverse osmosis concentrate effluent can be utilised by blending with sludge or used in fertiliser production.