AWWA ACE58095

Potable water plant operators face two major issues in the 21st century - raw water quality and quantity. Approximately 2/3 of the systems in use today draw groundwater as their source. The quality of source water can adversely impact the ability of the operator to pump it to the surface for treatment prior to supplying customers with a product that meets all regulatory requirements. Groundwater wells can become fouled due to silt and clays, mineral precipitates, or non- pathogenic bacteria (biofouling). This fouling can impede the pumping process, which reduces capacity and results in high operating costs, as well as expensive maintenance or replacement well cost. This paper discusses the most common causes of fouling that include: silts and clays; mineral precipitates; and, biological fouling. In the past, mechanical physical agitation, acid, and chlorine have all been used separately or in combination to address the above fouling problems. The paper discusses how, in order to adequately rehabilitate and meet the objective of returning a potable water well to its original capacity, the proper criteria must be met. A case study is presented on how the "Well-Klean Preblend" product was used to chemically rehabilitate a well in Lake Havasu City, Arizona.