Membrane Processes for Greywater and Rainwater Treatment

Abstract

As water scarcity being more urgent, water reuse has been receiving increased attention. Greywater (GW) is generally considered as municipal wastewater excluding that from kitchen and toilet flushing system (Nolde, 1999). With its low pollution level characteristics and representation of 60-70% of domestic wastewater (Friedler et al., 2005), GW is an ideal source for water reclamation. On the other hand, rainwater (RW) or stormwater also serves as an alternative water source, and is considered as one of the best existing approach to sustainable urban development (Kim et al., 2005). People in Thailand have been using RW as drinking water for centuries, especially in rural areas. Similar practice occurs in Bermuda as the residents harvest RW on rooftops to satisfy their freshwater needs (Levesque et al., 2008). Common pollutants in RW are found to be microorganisms, particles, colloids, heavy metals, organics, etc.. They originate from the contacts with the air and catchment surfaces, which make RW even less contaminated than GW, and hence an alternative for water recycling.Membrane bioreactor (MBR) technology is promising in water reclamation as it produces good effluent quality, provides various plant sizes, and increases treatment system reliability while lowers the latent reuse risks (Fane and Fane, 2005). The feature of long solids retention times (SRTs) results in the ease of MBR operation. Recently, considerable research has been conducted on using MBRs to treat GW and RW, together with other treatment technologies; the effluent quality of MBRs has been found to be sufficient to meet current domestic wastewater reuse standards. However, information has not been reviewed and summarized on the performance (e.g., treatment efficiency and membrane fouling) of MBRs in GW and RW treatment under different conditions, with the influence of different operational parameters, and in combinations with different pretreatment technologies.This chapter first presents an overview of using MBRs to treat GW and RW in terms of treatment performance, affecting parameters and membrane fouling, and then provides a case study on using the combination of a shredded tire biofilter (STB) 382 Membrane Technology and Environmental Applications Downloaded from ascelibrary.org by New York University on 04/11/15.