Effects of Wastewater Quality and Quantity Fluctuations in Selecting the Wastewater Treatment Plant: a Case Study of Surabaya’s Mall

Abstract: The contamination of Surabaya’s water river, one of the reasons, is caused by the lack functioning of Wastewater Treatment Plant (WWTP). If the WWTP can be designed properly and in accordance with wastewater flow and characteristics, then the operation of WWTP is expectedly able to overcome or to reduce the water river contamination. Effects of wastewater quality and quantity fluctuations are considered as highly influential in the selection ofthe WWTP. The fluctuations are measured by wastewater sampling on H-Mall, with the flow measurement and laboratory analysis of COD, BOD, TSS, NH3, PO4, and O&G parameters. Wastewater quality and quantity in H-Mall of Surabaya are fluctuating hourly in a day, daily in a week, and the control chart analysis found that the parameters of TSS, NH3 and PO4 exceeds the 3 standard deviation. The design of the equalization basin for WWTP is considerably needed, not only due to the existence of quality and quantity fluctuations, but also due to the Malls in Surabaya city are commonly have only 12 hours operation a day. The calculation of anaerobic filter WWTP, with the 90 % removal efficiency, produces the effluent WWTP that meets the current quality standards. With the size of 295 m2, it is possible to be built in the parking area of H-Mall