Development of combined membrane filtration, electrochemical technologies, and adsorption processes for treatment and reuse of laundry wastewater and removal of nonylphenol ethoxylates as surfactants

In this paper, we investigated the treatment and reusability of laundry wastewater (LW) by novel sequential integrated system including ultrafiltration (UF) of raw wastewater at first step and treatment of filtrate (permeate effluent) by the use of either adsorption processes (AD) (granular activated carbon GAC or polymeric resin PR) or nano-filtration (NF) system, or electro-oxidation (EO) to remove mainly total suspended solids (TSS), turbidity, chemical oxygen demand (COD), and surfactants such as nonylphenol ethoxylates (NPEO3-17) in order to meet the environmental rejection and reusability standards. Concentrate (retentate effluent) of UF and NF were also treated using electrocoagulation (EC) and electro-oxidation (EO) methods, respectively. Optimum conditions in order to obtain best results were determined in each case. The UF separated the raw wastewater into a filtrate with a low organic pollutant content (300-400 mg/L of dissolved COD) and a concentrate with a total COD of 700-1200 mg/L and 140-200 mg TSS/L. Following application of UF, NPEO3-17 were found not only in the concentrate but also in the filtrate and subsequently were treated using mentioned techniques which was effectively removed by NF and AD.