AWWA ACE61846

The selection of the most appropriate treatment technology for arsenic, perchlorate, and nitrate is a challenge, and must take into account the ultimate fate of the generated liquid or solid waste. A treatment technology that provides good treatment performance in one location may not be suitable for other locations due to the limited discharge options, or distance to disposal facility, etc. This project investigated treatment alternatives for residuals from arsenic, perchlorate, or nitrate treatment processes, a step which had been often overlooked in the past when making a process selection. The water quality needs to be thoroughly characterized even if individual contaminant levels may be lower than the drinking water guidelines. Many technologies concentrate contaminants in waste streams, and this may result in residual levels that exceed discharge or disposal regulations. In order to effectively implement a treatment system, understanding the local, state, and federal drinking water regulations (current and future) as well as discharge and disposal guidelines are critical steps. It is also important to recognize that each project is unique and that overall arsenic, perchlorate, and nitrate management requires a multifaceted approach that integrates technology, cost, regulation, and the public. An integrated approach must be used when defining and designing new treatment processes for these contaminants to fully understand and capture all potential issues associated with wastes generated during treatment process. The potential type of residuals from the selected treatment approaches identified earlier can significantly increase the overall cost to produce water. Thus, types of residuals produced (e.g. liquid, solid, high brine), local discharge and disposal regulations (types and limits), proximity to regeneration, disposal and discharge facilities, capital and O&M cost for residual treatment, should be carefully considered in developing fully integrated residual management approach. Includes 33 references, tables.