Application of UF/NF/RO membranes for treatment and reuse of rendering plant wastewater

Abstract

The treatment of animal by-products in rendering plants consumes large amounts of water generating wastewater with high content of organic matter. Literature review has shown that there is no study that evaluated the application of membrane technology for the treatment of rendering plant wastewater (RPW) and its reuse. A combination of sequential batch reactor (SBR), sand filtration, ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) was used to treat the RPW. Three UF (MW, GM, and CQ), two NF (NF90 and NF270), and one RO membrane (XLE) were tested along with the water analysis (conductivity, pH, turbidity, chemical oxidation demand, and contents of carbon, nitrogen, and phosphates) at each step of the process. During UF, the high content of effluent organic matter (EfOM) caused severe fouling. Sand filtration was an effective pretreatment for UF, lowering the fouling. The most suitable combination of membranes according to their separation efficiency and permeability was selected. The quality of permeates confirms its reusability in the process for washing and steam generation.