p+d has completed a study that determined the deficiencies contributing to high levels of trihalomethanes (THM) in the water supply for the Town of Wallkill. THM occur within water systems as a result of the necessary disinfection process used to rid drinking water of naturally occurring microorganisms such as bacteria and viruses. Chlorine, commonly used within the disinfection process, can sometimes react to these microorganisms and create harmful disinfection byproducts such as THM. According to the World Health Organization (WHO), a high level of THM in drinking water can lead to ill effects on the body such as “colon cancer for those aged 60 years or more and bladder cancer among non-smokers.” WHO also explains the significant factors that come together to potentially increase THM levels in drinking water: “the type and concentrations of organic materials in the raw water, the chlorine reaction time, temperature, and chlorination pH.” The study conducted by p+d had to focus on each factor in order to arrive at an effective solution for eliminating the harmful substance.
The Town of Wallkill was required to release a statement to residents in August of 2018 alerting them to the heightened levels of THM and residents were again warned early this year about the potential contaminants.
The Town accepted a proposal from p+d on January 23, which allowed us to evaluate their treatment process, storage system, and distribution network to discover the deficiencies contributing to the high levels of THM. More specifically, we proposed a project to install an agitator within the Town’s water storage tanks and thoroughly clean the inside of the tanks, ridding its walls of any organic materials that might be interacting with the chlorine. The agitator circulates the water to lower its age and prevent thermal stratification.
Most important to us is ensuring that the Town will experience long-term benefits from our evaluation and improvements. We are now in the process of designing the tank rehabilitations and conducting the cleaning that was recommended post-study. Providing continued rehabilitation of the greensand filters at each of the Town’s treatment plants and the installation of a chlorine booster station near the Washington Heights Storage Tanks will allow the Town to maintain a required free chlorine residual of 0.2 mg/l.
