Field Testing of a Small Water Purification for Non-PRASA Rural Communities

Small, rural communities typically do not have adequate water purification systems for protection from pathogens in drinking water. In Puerto Rico (PR), approximately 4% of the population does not have access to drinking water provided by the Puerto Rico Aqueduct and Sewer Authority (PRASA). These communities rely on their own water purification systems. These systems are called the Non-PRASA Systems and range from having no treatment to filtration treatment followed by disinfection. There are about 240 Non-PRASA Systems in PR. An experimental drum slow sand filtration (EDF) and chlorination system has been installed in a PR rural community where the system will be run by gravity alone (Solar power is necessary for the test system. The goal is to have a unit that is solely dependent on gravity for energy). The EDF system was initially designed and preliminarily tested at the U.S. Environmental Protection Agency (EPA) Test & Evaluation (T&E) Facility in Cincinnati, OH. The filtration system consists of three 55-gallon drums; each drum is packed with three different grades of sand. Each drum filtration unit can be backwashed independently to provide an uninterrupted filtered water supply. Chlorine is added pre and/or post filtration. Engineering operating parameters such as flow rates, filtration time, and biochemical characteristics such as turbidity, total and free residual chlorine concentrations, and indicator microorganisms have been tested. The EDF systems will be deployed to rural communities in need of reliable but low-cost/low maintenance water purification systems for sustainable water supplies and protection from water-borne pathogens.