Comprehensive utilization of phosphate in a highly concentrated recirculating cooling water system using secondary-treated municipal wastewater as make-up. Issue 22 (8th May 2016)

• Record Type: Journal Article
• Authors: Wang, Dong; Wang, Jun; Luan, Zhao-kun; Wu, Ying; Li, He-sheng
• Is Part Of: Desalination and water treatment. Volume 57:Issue 22(2016)
• Page Start: 10210
• Page End: 10221
• Publication Date: 2016-05-08
• Subjects: Phosphate -- Secondary-treated municipal wastewater -- Comprehensive utilization -- Corrosion -- Recirculating cooling water system (RCWS) -- Make-up; Saline water conversion -- Periodicals; Saline water conversion; Water -- Purification; Periodicals; 628.167
• DOI: 10.1080/19443994.2015.1037354
• Languages: English
• ISSNs: 1944-3994

Abstract

Abstract: A comprehensive utilization process using phosphate was developed for the reuse of high hardness secondary-treated municipal wastewater to a highly concentrated recirculating cooling water system (RCWS). It showed that the soluble phosphate in the wastewater could be directly reused as a corrosion inhibitor to prevent the RCWS from severe corrosion caused by the contaminants in the wastewater. Based on the synergetic corrosion inhibition of and Zn 2+, a chemical program was achieved for recirculating cooling water treatment. It contains 1-hydroxyethylidene-1, 1-diphosphonic acid, polyepoxysuccinic acid, zinc sulfate heptahydrate, and a copolymer dispersant of LN-104B. In addition, LN-104B was verified to have excellent inhibition capability to calcium phosphate scale and zinc salts scale in the bench experiments. The pilot-scale experimental results showed that the simulated RCWS operated very well under the condition of high Ca 2+ concentration (1, 500 mg/L as CaCO3 ) using the chemical program and automatic pH-controlled technique. The corrosion rate and the adhesion rate of the test tubes are only 0.023 mm/a and 2.32 mcm, respectively, which perfectly meet the requirements of the international standard of ISO 16784-2006. Not only can the process cut down the operating cost of RCWS, but also can reduce the environmental risk caused by excessive emission of phosphate. Moreover, large amounts of fresh water and phosphorus resources are expected to be conserved.