Development of Malaysian wastewater polishing index: Case study on a moving bed biofilm reactor

Abstract

Currently, extra treatment of secondary effluent to remove nitrogen and phosphorous may be required for its unrestricted reuse. This can be achieved by installing the wastewater polishing systems (or tertiary treatment).The wastewater polishing solutions are environmentally friendly, cheap and effective. The experiments were conducted on a pilot scale using a Moving Bed Biofilm Reactor (MBBR) with a capacity of 500 L to polish the municipal effluent from organic pollutant, undesirable nutrients and bacteria without the use of disinfectants. The major purpose was to define and apply a model for evaluating polishing of secondary effluent and implement the optimal technology for unrestricted use. Wastewater Polishing Index (WWPI) is a new tool that has been employed for rapidly evaluating of water quality improvement. It can be implemented into any surface water effluent treatment system or for reuse. WWPI can be an important tool designed for decision makers. The total average weight of six parameters (COD, BOD5, SS, Ammonia nitrogen, Total Phosphorus and Escherichia coli) are defined as the index, each one converted to sub-index which is scaled from zero to one hundred. If none of six parameters exist in the effluent WWPI, it is equal to zero, while if the parameters match the Malaysian's effluent Standard B, It amounts to one hundred. In turn, WWPI is ninety when all six of them are equal to their corresponding Malaysian National Water Quality Standard (IV) for re-use. The index of wastewater polishing was validated and approved for the pilot MBBR study.