Evaluation of Efficiently Removing Secondary Effluent Organic Matters (EfOM) by Al-Based Coagulant for Wastewater Recycling: A Case Study with an Industrial-Scale Food-Processing Wastewater Treatment Plant

• Published in: Membranes (Basel) Vol. 13; no. 5; p. 510
• Main Authors: Cheng, Yu, Cheng, Qiangqiang, Zhao, Chengjin, Ren, Xianghao, Wang, Yu, Kou, Yingying, Chon, Kangmin, Ko, Myung-Han, Hwang, Moon-Hyun
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 12.05.2023; MDPI
• Subjects: Acids; Aluminum sulfate; Aromaticity; Case studies; Chemical oxygen demand; Coagulants; Coagulation; Efficiency; Effluent treatment; Effluents; Flocculation; Food industries wastewaters; Food industry; Food plants; Food processing; Food processing industry; Fourier transforms; humic-like substance; Hydrophobicity; Infrared spectroscopy; Microorganisms; Organic matter; organic matters; Polyacrylamide; Processing industry; Proteins; Purification; Quality standards; secondary effluent; Sewage; Sludge; soluble microbial products; Spectrum analysis; Sustainable development; Technology application; Turbidity; Wastewater reuse; Wastewater treatment; Wastewater treatment plants; Water reuse; Water treatment; Water treatment plants; South Korea; China; Fiji; United Kingdom > UK; Beijing China; secondary effluent; soluble microbial products; organic matters; water reuse; humic-like substance; coagulation
• ISSN: 2077-0375; 2077-0375
• DOI: 10.3390/membranes13050510

The reuse of wastewater has been identified as an important initiative for the sustainable development of the environment; thus, the removal of secondary effluent organic matter (EfOM) to ensure the safety of reused wastewater is the key step and a subject of extensive research. In this study, Al (SO ) and anionic polyacrylamide were selected as coagulant and flocculant, respectively, for the treatment of secondary effluent from a food-processing industry wastewater treatment plant to meet the standard regulatory specifications for water reuse. In this process, the removal efficiencies of chemical oxygen demand (COD), components with UV , and specific ultraviolet absorbance (SUVA) were 44.61%, 25.13%, and 9.13%, respectively, with an associated reduction in chroma and turbidity. The fluorescence intensities (Fmax) of two humic-like components were reduced during coagulation, and microbial humic-like components of EfOM had a better removal efficiency because of a higher Log Km value of 4.12. Fourier transform infrared spectroscopy showed that Al (SO ) could remove the protein fraction of the soluble microbial products (SMP) of EfOM by forming a loose SMP protein complex with enhanced hydrophobicity. Furthermore, flocculation reduced the aromaticity of secondary effluent. The cost of the proposed secondary effluent treatment was 0.034 CNY t %COD . These results demonstrate that the process is efficient and economically viable for EfOM removal to realize food-processing wastewater reuse.