Use of EM Technology (EM) in water treatment: Urban sewage water treatment plan, a city slaughter house, and a natural estuary in Guayaquil, Ecuador

Abstract

The following article describes three case studies where Effective Microorganisms (EM) proved to be successful at recovering natural aquatic ecosystems as well as treating sewage and industrial waste water. The first case was at a water treatment plant that received the sewage water from two populated sectors of about 1’100,000 people within Guayaquil, the largest city in Ecuador. The efficacy of EM treatment was compared to an already established water treatment system using electrical aerators. In both cases, pH was maintained at a neutral range after 8 weeks and hydrogen sulfide, main cause of foul odors, was not detected after 5 weeks. The most significant difference was in the cost and used of energy. The second case consisted of treating the facilities of a slaughterhouse processing 1000 animals a day with the objective of reducing foul odors. EM was sprayed in all areas of the facility including floors, pathways, sewers and surrounding areas. Although no measurable parameters were evaluated, workers were interviewed to determine efficacy in reducing foul odors. After 5 months of treatment, employees and foremen agreed that foul odors were reduced almost completely to the point that employees did not feel the need to use masks. In addition, there was a consensus that the working conditions had significantly improved. The third case was the treatment of a natural estuary being contaminated with sewage water. Water samples and sediments were taken from the area receiving sewage water from the city sewage system. The following parameters were evaluated: Acidity, phosphates, organic matter, hydrogen sulfide, total suspended solids, populations of coliforms and salmonella. The results showed a significant decrease in phosphates, total suspended solids, organic matter and hydrogen sulfide, and a reduction in concentration of coliforms. Additionally, pH was maintained at neutral range allowing the proliferation of native life. These experiences demonstrate the versatility and efficacy of EM to mitigate water contamination due to human activities in populated cities.