Comparison on treatment strategy for chemical cleaning wastewater: Pollutants removal, process design and
Zhen Zhou1, Danian Ruan2, Lu-Man Jiang2
1College of Environmental and Chemical Engineering, Shanghai University of Electric Power, 2588 Changyang Road, Shanghai 200090, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
Abstract:
Chemical cleaning wastewater (CCW) usually consists of pickling wastewater (PW) and alkaline cleaning wastewater (ACW), and the strategy of separate treatment or combined treatment affects pollutant removal efficiency and cost. In this study, separate and combined treatment of real PW and ACW generated from an on-site cleaning campaign were investigated. A neutralization - fluoride removal - coagulation - oxidation process was constructed for PW and mixed wastewater (MW) treatment, and operational conditions of each process were optimized. The optimal mixing ratio of PW and ACW in the primary neutralization tank was 3:7, which obtained a near neutral pH, efficient chromaticity and turbidity removal and good settling performance. The neutralized MW and PW were both adjusted pH to 9.5 to precipitate metal ions as hydroxides. After fluoride precipitated as CaF2, the fluoride removal rates of MW and PW were both 99.9%, respectively, and polyaluminum chloride was dosed to improve the settleability of CaF2. Then sodium hypochlorite oxidization was employed to remove NH3-N and soluble COD. Techno-economic analysis based on pilot-scale tests showed that separate treatment of PW and ACW obtained better effluent quality than combined treatment. The total cost of combined treatment (37.44 $/m3) was greatly higher than that of separate treatment of PW and ACW (18.20 $/m3). This study proposed a cost-effective strategy for CCW treatment, and suggested that neutralization with acidic or alkaline wastewater should be systematically considered for technical and economic feasibility.
Related Concept Videos
Treatment Strategies for Psychological Disorders
Psychological therapies focus on modifying emotions, thoughts, and behaviors through talking, interpreting, listening, rewarding, challenging, and modeling. Clinical psychologists, counselors, and social workers commonly practice psychotherapy. Clinical...
Cleaning, Sterilization, and Disinfection
Cleaning
The cleaning process usually involves using water with detergents or enzymatic cleaner and removing foreign material from objects and surfaces, including organic material such as body fluids or inorganic material like soil. Cleaning is performed before high-level disinfection and sterilization because foreign materials on the cover of the devices interfere with process...
The Sense of Self: Reflected Self-Appraisal and Social Comparison
Design of Transmission Shafts - Stress Analysis
Group Design
Chemical Equations


