Integrated membrane system for distributed water treatment

Abstract

Integrated membrane treatment systems for treatment of an aqueous solution. In embodiments, components, such as an MBR, are integrated with means to recover energy from the system, for example from an RO concentrate, to operate the other components. In embodiments including biological treatment, RO is integrated with other components, such as an MBR with the ROs ability to remove inorganic nitrogen enabling biological treatment to be performed with only partial nitrification and the MBR operated without active pH control. In embodiments, RO is integrated with a chlorine generator to convert chlorides present in the RO concentrate for an in-situ source of oxidizing biocides for disinfection purposes. Chloramines may be generated in-situ from residual ammonia and chlorides in the RO reject. In embodiments, carrier media is employed in a membrane tank to enhance removal of residual organics by the MBR and to also improve effectiveness of membrane scouring.

1 . A water treatment system, comprising:
 a vessel for filtration or treatment of an aqueous solution;   a reverse osmosis (RO) unit; and   an electrolytic cell in fluid communication with an RO concentrate outlet, the electrolytic cell operative to convert a salt in the RO concentrate into an oxidizing species, wherein the electrolytic cell is coupled to at least one of the vessel and RO unit for disinfection by the oxidizing species or reaction products thereof.   
     
     
         2 . The water treatment system of  claim 1 , wherein the oxidizing species comprises chlorine and wherein the reaction product comprises a chloramine product of a reaction between residual ammonia in the RO concentrate and the oxidizing species. 
     
     
         3 . The water treatment system of  claim 1 , wherein the electrolytic cell has an outlet coupled downstream of the vessel for conduction of the oxidizing species to the RO inlet. 
     
     
         4 . The water treatment system of  claim 1 , further comprising a backwash apparatus to intermittently provide a liquid back-pulse from an effluent side to an influent side of a membrane filter in the vessel, the liquid back-pulse containing the oxidizing species. 
     
     
         5 . The water treatment system of  claim 4 , further comprising a hydraulic pump with a high pressure side in fluid communication with the RO inlet and an RO bypass upstream of the RO inlet, wherein the backwash apparatus is in fluid communication with both the electrolytic cell and with the RO bypass, the liquid back-pulse to be pressurized by the pump. 
     
     
         6 . A water treatment method, comprising:
 performing an incomplete biological treatment of an aqueous solution leaving residual ammonia in the treated effluent, wherein performing the incomplete biological treatment further comprises performing treatment without adding a caustic to control pH; and   removing the ammonia from the treated effluent by driving the treated effluent through a reverse osmosis (RO) unit with a hydraulic pump.   
     
     
         7 . The water treatment method of  claim 6 , further comprising
 electrolytically converting a chloride in a RO concentrate of the RO unit into a chlorine-containing oxidizing species;   reacting the chlorine-containing oxidizing species with the residual ammonia in the RO concentrate to generate chloramines; and   disinfecting at least a portion of a system performing the water treatment method with the generated chloramines.   
     
     
         8 . The water treatment method of  claim 7 , the method further comprising filtering the treated effluent with a membrane filter, and wherein disinfecting at least a portion of the system further comprises, at least one of:
 intermittently backwashing the membrane filter with a liquid back-pulse from an effluent side to an influent side, the liquid back-pulse pressurized by the hydraulic pump and carrying the chloramines,   introducing the generated chloramines to a feed tank disposed downstream of the filtration vessel and upstream of the hydraulic pump to expose an influent side of the RO unit to the chloramines, or   introducing the generated chloramines into the RO permeate.   
     
     
         9 . A water treatment method, comprising:
 performing at least one of filtration or biological, chemical, or physical-chemical treatment of an aqueous solution;   removing salts from the filtered or treated effluent by driving the effluent through a reverse osmosis (RO) unit with a hydraulic pump;   electrolytically converting a salt in the RO concentrate into a chlorine-containing oxidizing species; and   disinfecting at least a portion of the system performing the water treatment method with the chlorine-containing oxidizing species.   
     
     
         10 . The water treatment method of  claim 9 , the method further comprising filtering the treated effluent with a membrane filter, and wherein disinfecting at least a portion of the system further comprises, at least one of:
 intermittently backwashing the membrane filter with a liquid back-pulse from an effluent side to an influent side, the liquid back-pulse pressurized by the hydraulic pump and carrying the chlorine-containing oxidizing species,   introducing the generated chloramines to a feed tank disposed downstream of the filtration vessel and upstream of the hydraulic pump to expose an influent side of the RO unit to the chlorine-containing oxidizing species, or   introducing the generated chlorine-containing oxidizing species into the RO permeate.   
     
     
         11 . A water treatment method, comprising:
 providing a waste water comprising ammonia and having a first pH;   treating the waste water by oxidizing the ammonia to provide a treated effluent, the treated effluent having a second pH lower than the first pH; and   driving the treated effluent through a reverse osmosis (RO) unit, the second pH sufficient to reduce scaling of the RO unit.   
     
     
         12 . The water treatment method of  claim 11 , wherein the treated effluent comprises residual ammonia, the method further comprising:
 removing the residual ammonia with the RO unit.   
     
     
         13 . The water treatment method of  claim 2 , further comprising:
 electrolytically converting a chloride in a RO concentrate of the RO unite into a chlorine-containing oxidizing species;   reacting the chlorine-containing oxidizing species with the residual ammonia in the RO concentrate to generate chloramines; and   disinfecting at least a portion of A system performing the water treatment method with the generated chloramines.   
     
     
         14 . The water treatment method of  claim 13 , the method further comprising:
 filtering the treated effluent with a membrane filter, and wherein disinfecting at least a portion of the system further comprises, at least one of:   intermittently backwashing the membrane filter with a liquid back-pulse from an effluent side to an influent side, the liquid back-pulse pressurized by the hydraulic pump and carrying the chloramines,   introducing the generated chloramines to a feed tank disposed downstream of the filtration vessel and upstream of the hydraulic pump to expose an influent side of the RO unit to the chloramines, or   introducing the generated chloramines into the RO permeate.   
     
     
         15 . The water treatment method of  claim 11 , wherein the treating the waste water is performed without adding a caustic.