Physicochemical pre- and post-treatment of coking wastewater combined for energy recovery and reduced environmental risk

Zemin Li; Tuo Wei; Jiamin Pan; Yitong Liang; Zixin Ban; Xiong Ke; Qiaoping Kong; Guanglei Qiu; Yun Hu; Sergei Preis; Chaohai Wei

doi:10.1016/j.jhazmat.2023.130802

Physicochemical pre- and post-treatment of coking wastewater combined for energy recovery and reduced environmental risk

J Hazard Mater. 2023 Apr 5:447:130802. doi: 10.1016/j.jhazmat.2023.130802. Epub 2023 Jan 16.

Authors

Zemin Li¹, Tuo Wei¹, Jiamin Pan¹, Yitong Liang¹, Zixin Ban¹, Xiong Ke¹, Qiaoping Kong², Guanglei Qiu¹, Yun Hu³, Sergei Preis⁴, Chaohai Wei⁵

Affiliations

¹ School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
² School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China.
³ School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China.
⁴ Laboratory of Environmental Technology, Department of Materials and Environment Technology, Tallinn University of Technology, Tallinn 19086, Estonia.
⁵ School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China. Electronic address: cechwei@scut.edu.cn.

PMID: 36669414
DOI: 10.1016/j.jhazmat.2023.130802

Abstract

In this study, physicochemical pre- and post-treatment of highly polluting coking wastewater (CWW) for the removal of refractory compounds and recovery of high-energy substances/components was investigated. An economic optimization model targeting the development of a cost-effective and sustainable treatment technology was proposed. At the post-treatment stage, powdered activated carbon (PAC) was used to separate the refractory and toxic pollutants from the bio-treated CWW, with the adsorption capacity ranging from 50 to 120 mg chemical oxygen demand (COD) g^-1 PAC. Then, the spent PAC, together with a coagulant, was reused in the pre-treatment of highly concentrated raw CWW, which lifted the adsorption capacity to 800-1200 mg COD g^-1 PAC. Results showed that the adsorbent's high selectivity towards macromolecular and complicated pollutants could remove 25-65 % of COD in both CWW flows. Analysis of pollutants' molecular weight distribution and GC-MS indicated a good affinity between PAC and high-energy pollutants (phenolic compounds and alkanes), which could transfer 144,555 kJ m^-3 of energy from CWW to the adsorption-coagulation sludge. The economic optimization model suggested that the cost of the adsorbent was compensated by the net benefits of energy recovery and that profit was achieved when the PAC price was less than 5562 CNY t^-1. The proposed two-stage PAC/coagulant approach offers a way to sustainable water quality and sludge management, plus energy recycling, in CWW treatment. It may also be applied to the treatment of other industrial wastewaters.

Keywords: Adsorption; Coking wastewater (CWW); Economic optimization model; Energy; Physicochemical pre- and post-treatment.