Improvement of Water Treatment Plant Process for Arsenic and Manganese Removal

Abstract

ABSTRACT The City of White Rock acquired the water system from EPCOR in October 2015. The City of White Rock decided to build a water treatment plant to treat the City’s existing groundwater supplies to remove naturally occurring manganese and arsenic to ensure that an improved drinking water quality is supplied to City residents that meets the Canadian guidelines and esthetic objectives. The City’s water supply is from groundwater wells located within the City municipal boundaries drawing from the confined Sunnyside Aquifer. There are seven operating, drilled wells. The Water Treatment Plant was built at the Oxford Pumping Station area. Construction of the Design Build water treatment plant (WTP) started in March 2018. The plant started operation in March 2019. The WTP treatment design objectives are to deliver drinking water meeting the following operational targets; Mn <0.02 mg/L, As <0.002 mg/L (95% of time, 0.005 mg/L for 5% of operation). All other water quality parameters shall meet the objectives of the Guidelines for Canadian Drinking Water Quality (GCDWQ) without treatment. The initial water quality data showed a significant removal of arsenic and manganese. However, after a few weeks of operation, the WTP performance for arsenic and manganese started to decline. Regeneration of the filter media was discussed with the contractor and manufacturer and implemented. The sequential regeneration of the four adsorbers was conducted successfully over a two-week period. Following the regeneration, arsenic concentration in the treated water effluent from the four parallel adsorbers was well within the water treatment plant Design Objectives of <0.002 mg/L. The staff of the Water Department worked to optimize the operation and make the changes needed to improve the performance of the plant.