Abstract: Apparatus and methods are provided for removing solids from wastewater. The apparatus may include a dissolved solids removal system including a first membrane stack for removing a first portion of dissolved solids from wastewater, the first membrane stack having a first rejection rate and including at least one first membrane having a first operating pressure rating. A first solution unit may be included downstream of the at least one first membrane, the first solution unit being configured to maintain a differential pressure over the at least one first membrane below the first operating pressure rating. The dissolved solids removal system may also include a final membrane stack for removing a final portion of dissolved solids from the wastewater, the final membrane stack being located downstream of the first membrane stack and having a final rejection rate higher than the first rejection rate.

Abstract: Methods and apparatus for removing contaminants from wastewater with a high salinity content are provided. The methods include injecting a flocculant and other agents and mixing it with the wastewater. The mixture is held in a clarifying tank. The resulting clarified product is filtered through a micro filter. In the final stage, the micro filter output is passed through a series of reverse osmosis membrane. To present a stream with the appropriate salinity for the reverse osmosis filter, the micro filter output is mixed with previously cleaned water to reduce the concentration of total dissolved solids.