Experimental study of coagulation-tubular microfiltration integrated with high-salt wastewater to remove hardness and silica

Abstract

In the zero-discharge treatment processes of high-salt wastewater, calcium ions, magnesium ions and silica can lead to scaling problems in membrane equipment and pipelines. When fouling is difficult to remove completely, it eventually leads to deterioration in the performance of the wastewater treatment system. In order to ensure the long-term stable operation of the zero-discharge process for high-salt wastewater, hardness and silica must be effectively removed in the pre-treatment section of high-salt wastewater. In addition, the current zero-discharge pre-treatment process for high-salt wastewater has disadvantages, such as long processes, poor system stability, large floor space and high operating costs. In response to the above problems, this paper designs and processes an integrated dosing coagulation-tubular microfiltration process for hardness and silica removal based on dosing coagulation experiments with high-salt wastewater from a typical coal-chemical plant, and conducts the tests of wastewater hardness and silica removal. In the experiment, the removal rate of calcium ions, magnesium ions and total silicon were close to 90%, the turbidity of the effluent was less than 1NTU, all suspended solids (SS) were removed, and the recovery rate of wastewater was close to 100%.