Utilization of an ultra-high pressure reverse osmosis membrane system to treat industrial wastewater or a reverse osmosis reject waste stream

A method for concentrating an industrial wastewater or reverse osmosis (RO) reject stream using a membrane-based process wherein a feed stream is pretreated to reduce suspended solids and hardness prior to an ultra-high pressure reverse osmosis (UHPRO) membrane system, comprising:

• receiving an industrial wastewater or RO reject stream that contains suspended solids and dissolved salts;
• directing the industrial wastewater or RO reject stream to a pretreatment step, comprising:
• 10i. pre-treating, as pretreated water, the industrial wastewater or RO reject to reduce concentration of suspended solids and/or total hardness to generate an effluent that contains low levels of total hardness;
• 10ii. in reducing suspended solids and/or hardness and generating an effluent that contains low levels of total hardness, also generating a pretreatment waste stream that contains removed suspended solids and/or hardness;
• and
• 10iii. directing the pretreatment waste stream, containing the removed suspended solids and/or hardness, to waste for disposal;
• after suspended solids and/or hardness removal, introducing a feed stream comprising dissolved salts into a UHPRO membrane system;
• operating, as an operating pressure, the UHPRO membrane system at an elevated feed pressure;
• maintaining average membrane flux between 2.0 and 6.0 gallons per square foot per day and a lead element flux not exceeding 10 gallons per square foot per day;
• conditioning the feed stream by adding at least one scale inhibitor and at least one surfactant configured to modify interfacial interactions between dissolved species and a membrane surface of the UHPRO membrane system,
• wherein the at least one surfactant is present at a concentration effective to reduce surface tension and inhibit nucleation and deposition of sparingly soluble salts and foulants on the membrane surface,
• wherein stable operation is achieved only when the operating pressure, membrane flux, and chemical conditioning are concurrently maintained within specified ranges,
• wherein stable operation comprises:
• (i) a normalized permeate flux decline of less than 10% over at least 5-7 days of continuous operation, and
• (ii) absence of irreversible membrane scaling requiring membrane replacement;
• and
• recovering a concentrate stream having a total dissolved solids (TDS) concentration of at least 100,000 mg/L.

A system for concentrating an industrial wastewater or reverse osmosis reject stream, comprising:

• an ultra-high pressure reverse osmosis (UHPRO) membrane system configured to operate at an elevated feed pressure as an operating pressure;
• a dosing system configured to introduce at least one scale inhibitor and at least one surfactant into a feed stream;
• and
• a control system configured to:
• (i) regulate feed pressure,
• (ii) control average membrane flux with a range of 2.0 and 6.0 gallons per square foot per day, and
• (iii) coordinate dosing of the scale inhibitor and surfactant in response to feedwater composition,
• wherein the control system maintains concurrent control of the operating pressure, flux, and chemical conditioning to achieve stable operation at total dissolved solids concentrations of at least 100,000 mg/L.