On the feasibility of small communities wellhead RO treatment for nitrate removal and salinity reduction.

The feasibility of wellhead water treatment in small communities for nitrate removal and salinity reduction via a flexible high recovery RO system was evaluated through analysis of treatment options, laboratory and onsite field tests. In small remote communities that rely on septic systems for residential wastewater treatment, discharge of the RO residual stream (containing nitrate) to the community septic tank is shown to be a feasible option. It is demonstrated that RO treatment with a system that employs partial concentrate recycle, integrated with a pressure intensifier, enabled the use of a relatively low-pressure feed pump while allowing high recovery operation. The approach of integrating RO treatment into existing community small water systems is demonstrated to be suitable for providing effective nitrate removal and salinity reduction over wide range of nitrate and salinity levels, while meeting community water demand and regulatory water quality requirements.