Comparative study of mixed liquor suspended solids (MLSS) concentration on sewage treated Biological Oxygen Demand (BOD) in Membrane Bioreactor (MBR) and Activated Sludge Process (ASP)

Abstract

The waste water Recycling is crucial to address the water scarcity created due to the increasing population and industrialization. In the process of sewage treatment and recycling the technology and governing factors are important. Therefore, this study was undertaken to reveal the comparative effects of varying MLSS concentrations on the treated water quality in both Membrane bioreactor (MBR) and Activated Sludge Process (ASP). To check the MLSS, samples of Bio culture were collected from aeration tank of Sewage Treatment Plant from various location. MLSS checked by standard methodology, MLSS indicates Population of Bio-culture present in the process. To check output of treated water samples physicochemical test such as BOD were performed by standardized methods for this comparative study. We have analyzed BOD since it indicates consumption of organic matter by bio-culture. BOD is important parameter which shows the reduction in pollution load or quality of the treated water. In MBR Technology we found MLSS minimum 5600 mg/lit and maximum 7500 mg/lit whereas BOD observed is 9 and 5 mg/lit respectively at same location. In Activated Sludge Process we found MLSS minimum 2800 mg/lit and maximum 4500 mg/ lit at the same location we found BOD 71 and 44 mg/lit respectively. We have analyzed the MLSS and BOD in order to study the concentration of MLSS or Bacterial culture and treated water BOD from the samples collected from outlet of Filtration in ASP and outlet of MBR in industrial as well as residential society STP locations. It was found from MBR technology that less BOD output results were obtained as compared to ASP. The conclusion of this study is higher concentrations of MLSS up to 5600 to 9500 mg/liter results in BOD around 5 to 9 mg/liter. Understanding the relationship between MLSS concentration and treatment performance can aid in the optimization of Sewage Treatment Plants (STP) operations and the development of sustainable wastewater treatment practices. From the study we can recommend to go for MBR Technology where we can maintain higher MLSS and can achieve lesser BOD results as compared to other technology like Activated Sludge Process (ASP).