Enhanced Purification and Disinfection of Restaurant Wastewater by Electro-coagulation Coupled with an Electro-oxidation Process: From Lab Scale to Field Scale

Abstract

Several Covid-19 infection events have been reported in restaurant and food-processing factory scenarios. To block the transmission of waterborne pathogens and protect human’s safety, it is urgent to take action for the purification and disinfection of restaurant wastewater. Considering the requirement of restaurant wastewater treatment technology, such as limited spaces, low capital cost, simple to operate, and high efficiency, an integrated electro-coagulation (EC) and electro-oxidation (EO) process was put forward. The lab-scale system treatment results illustrated that the composition of restaurant wastewater underwent significant changes. The chemical oxygen demand value decreased from 1680 to 344 mg/L. Total phosphate, total nitrogen, suspended solids, petroleum, animal fat and vegetable oils, and anionic surfactants achieved a distinct decrease. Moreover, the removal of Escherichia coli and Phi6 illustrated the satisfactory disinfection performance of the EC–EO system. The acute toxicity of the EC–EO effluent was reduced compared to that of raw wastewater. Comparing the results of EC treatment with EO treatment, the EC process provided more significant contributions to the purification and disinfection of wastewater than the EO process. The oxidants generated in the EO process would ensure the residual purification and disinfection performance through the long sewer pipe. The physical–chemical parameters and disinfection performances of the field-scale EC–EO system met the requirement of “Wastewater quality standards for discharge to municipal sewers-GB/T 31962-2015”. However, a certain amount of disinfectant byproducts were formed in the effluent. Moreover, the techno-economic analysis further illustrated the feasibility of the integrated EC–EO system for the purification and disinfection of restaurant wastewater.