POINT-OF-ENTRY TREATMENT OF PETROLEUM CONTAMINATED WATER-SUPPLIES

Contamination of individual wells in rural areas from leaking petroleum storage tanks poses unique problems for regulatory agencies, utilities, and potentially responsible parties. A potential solution is the use of point-of-entry (POE) treatment techniques. Results indicate POE systems using aeration followed by granular activated carbon (GAC) are a viable, cost effective, short-term solution while ground water remediation is performed or an alternate drinking water supply is secured. Selection and design of POE systems should consider variations in water usage and contaminant concentrations. Iron and manganese did not affect POE system performance at the ten sites studied. However, iron precipitation was observed and may pose problems in some POE applications. Increased concentrations of nonpurgeable dissolved organic carbon consisting primarily of methy-t-butyl ether (MTBE) and hydrophilic petroleum hydrocarbons were found in the raw waters but did not affect volatile organic chemical (VOC) removals by aeration or GAC. Microbial activity as measured by heterotrophic plate count significantly increased through four of the ten POE systems studied. Reliability of the POE systems will best be achieved by specifying top quality system components, educating POE users, and providing routine maintenance and VOC monitoring.