Performance assessment of a side-stream membrane bioreactor for the treatment of kitchen wastewater

Wastewater recovery from different sources is a prominent solution to the present water crisis. Membrane bioreactor (MBR) is one of the eminent separation processes to enable reusable water. Hence, the significance of the present study is to treat kitchen wastewater (KWW) by bioreactor integrated membrane processes. The in-situ microbial consortium prepared from the KWW was used in the bioreactor, which helped in degradation of the pollutants under continuous aeration. The indigenously synthesized nanofiltration (NF) membrane made of hydrophilized polyamide (HPA) was characterized by scanning electron microscopy (SEM), X-Ray Diffraction (XRD), and contact angle measurement to study crystalline nature, morphology, and hydrophilicity, respectively. From the experimental results, maximum water recovery and permeate flux of 82%, and 79 L/m2h were obtained through MBR at an optimum pressure of 10 kg/cm2 for 733 s, respectively. Significant reduction in impurities was observed, by removal of 97.6% chemical oxygen demand (COD), 93.7% total dissolved solids (TDS), 94.6% total suspended solids (TSS), and 98.5% turbidity, along with complete removal of color by integration of the bioreactor with NF process on the 12th day of operation. Further, the process was scaled-up to a pilot plant level, and a cost estimate for the production of reusable water is presented. The obtained water was found fit for reuse in various domestic applications, facilitating freshwater consumption and, therefore water conservation.