SOFTENING EE&T has conducted several pilot-scale softening studies including one for the Marine Corps Air Station located in Cherry Point, NC, City of White Sulphur Springs, WV, and the City of Tulsa, OK. Testing at Cherry Point included a pilot-scale evaluation of solids contact, spiractor softening treatment, and using pellet softening in combination with raw water prefiltered ozone. The pilot program focused on five treatment issues: Reduction of finished water turbidity Reduction of TOC and DBP formation potential Maintenance of disinfectant residuals Compliance with lead, iron, and manganese MCLs Residuals handling and dewatering The pilot evaluation showed that spiractor softening (with lime or sodium hydroxide), solids contact softening, and pellet softening in combination with raw water prefiltered ozone to be acceptable softening treatment methods that also reduced metals concentrations to acceptable levels. Spiractor softening was recommended due to ease of operation, treatment performance, and minimization of residuals generated. The project also included an extensive evaluation of ozone to provide the process disinfection and disinfection by-products control. Bench-scale tests were used to determine the effects of chemical sequence addition, various coagulants, and different polymers on the turbidity of the finished water. The test data developed during the study was used to design and construct a 6 mgd water plant. EE&T conducted a pilot-scale treatability study for the City of White Sulphur Springs, WV that focused on both water quality and process performance issues. The study objectives were evaluated by conducting pilot treatability studies that simulated treatment process conditions expected in a full-scale facility. The pilot study investigated various softening options for the future operation of the plant. Water quality goals for the treatment study included maintaining finished water sodium levels at less than 20 mg/L, finished water hardness in the 110 to 120 mg/L range, and compliance with West Virginia Drinking Water Regulations. Spiractor and filter media performance were assessed for various chemical feed scenarios (lime, sodium hydroxide, and potassium hydroxide). Pilot study results indicated that sodium hydroxide feed was the lowest cost alternative that would allow the City to maintain a relatively simple treatment operation with existing staff. The City of Tulsa, OK retained EE&T to conduct pilot-scale evaluations of: Softening versus conventional coagulation with pre-ozonation Softening with pre-ozonation Coagulation with polymer The combination of using pre-ozonation and softening The project was intended to assess the impacts of each treatment condition on reductions in DBP formation, while also considering a hardness goal of 100 mg/L as CaCO3. Coagulants evaluated in this work included alum and ferric chloride. Organics reduction methods included the use of pre-oxidant ozone and lowered coagulation pH.