Filtration columns containing waste iron shavings, loofah, and plastic shavings for further removal of nitrate and phosphate from wastewater effluent

Xiaoyu Cheng; Hongbo Feng; Yifan Liang; Lincong Li; Yunbo Yao; Minghui Jin; Jun Li

doi:10.1016/j.scitotenv.2023.162799

Filtration columns containing waste iron shavings, loofah, and plastic shavings for further removal of nitrate and phosphate from wastewater effluent

Sci Total Environ. 2023 Jun 10:876:162799. doi: 10.1016/j.scitotenv.2023.162799. Epub 2023 Mar 11.

Authors

Xiaoyu Cheng¹, Hongbo Feng¹, Yifan Liang¹, Lincong Li², Yunbo Yao², Minghui Jin², Jun Li³

Affiliations

¹ Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China.
² Yuhang Chengxi Water Purification Co., Ltd., Hangzhou 311121, China.
³ Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China. Electronic address: tanweilijun@zjut.edu.cn.

PMID: 36914123
DOI: 10.1016/j.scitotenv.2023.162799

Abstract

A novel pilot-scale advanced treatment system combining waste products as fillers is proposed and established to enhance the removal of nitrate (NO₃^--N) and phosphate (PO₄^3--P) from secondary treated effluent. The system consists of four modular filter columns, one containing iron shavings (R1), two containing loofahs (R2 and R3), and one containing plastic shavings (R4). The monthly average concentration of total nitrogen (TN) and total phosphorus (TP) decreased from 8.87 to 2.52 mg/L and 0.607 to 0.299 mg/L, respectively. Micro-electrolysis of iron shavings produces Fe²⁺ and Fe³⁺ to remove PO₄^3--P, while oxygen (O₂) consumption creates anoxic conditions for subsequent denitrification. Gallionellaceae, iron-autotrophic Microorganisms, enriched the surface of iron shavings. The loofah served as a carbon source to remove NO₃^--N, and its porous mesh structure facilitated the attachment of biofilm. The plastic shavings intercepted suspended solids and degraded excess carbon sources. This system can be scaled up and installed at wastewater plants to improve the water quality of effluent cost-effectively.

Keywords: Nitrate and phosphate removal; Secondary treated effluent; Waste iron shavings; Waste loofah; Waste plastic shavings.