Electrochemical process for simultaneous removal of chemical and biological contaminants from drinking water.

Abstract

Simultaneous management of chemical and biological contaminants in drinking water has been presented through modification in conventional electrocoagulation (EC) process. Traditional EC process using iron and aluminum electrodes removed metals but did not affect microbiological contaminants to a greater extent. Iron anode composition was amended by addition of zinc for desired antimicrobial output. To evaluate the efficiency of this system, samples were spiked with multiple element standard and microbial cultures to human unsafe contamination level. Modified EC process removed both types of contaminants making water safe for human consumption within the prescribed regulatory guidelines set by WHO/NSDWQ within 4 min. This setup removed chemical contaminants up to 100% including nitrates, fluoride, arsenic, beryllium, chromium, copper, mercury, vanadium, zinc, nickel, phosphorus, and lead. A substantial removal in cadmium (89.8%), cobalt (75.7%), and selenium (46.7%) was computed. The treatment could not prove good results for removal of boron, barium, lithium, and strontium from the spiked sample. The compositional analysis of flocs screened after spiked sample treatment confirmed the physical adsorption of metals at floc surface. Treatment technique comprehensively proved equally efficient for disinfection of most common microbiological contaminations including E. Coli, fecal coliforms, total coliforms, total plate count, Staphylococcus auseous, and Pseudomonas aeruginosa within 5 min. In EC process 220V voltage was applied through rectifier at electrodes having 15.6 cm2 surface area and 15 mm apart in 1-L water sample batches, where current varied from 0.8 to 1.6 ampere. The outcomes of the current experiment are of novel significance regarding simultaneous removal of metals and microbiological contaminants from drinking water which is not reported in previous treatment studies.