Abstract: A method of producing purified water in a subsurface environment is provided in which ambient subsurface source water is introduced into and through one or more ultrafiltration membrane units of a subsurface water treatment system and producing thereby an ultrafiltrate substantially free of solid particulates having a largest dimension greater than 0.1 microns. An electrochemical unit in fluid communication with at least one ultrafiltration membrane unit provides an antifoulant solution. An ultrafiltrate-rich backwash fluid and at least a portion of the antifoulant solution are delivered to at least one non-producing ultrafiltration membrane unit during a backwash cycle. A flux of source fluid through each of the ultrafiltration membrane units of less than thirty gallons per square foot per day limits the need for backwash cycles. A reduction in the number of backwash cycles enhances system autonomy and useful life, and limits the need for intervention for maintenance and component replacement.

Abstract: A method of producing purified water in a subsurface environment is provided in which ambient subsurface source water is introduced into and through one or more ultrafiltration membrane units of a subsurface water treatment system and producing thereby an ultrafiltrate substantially free of solid particulates having a largest dimension greater than 0.1 microns. An electrochemical unit in fluid communication with at least one ultrafiltration membrane unit provides an antifoulant solution. An ultrafiltrate-rich backwash fluid and at least a portion of the antifoulant solution are delivered to at least one non-producing ultrafiltration membrane unit during a backwash cycle. A flux of source fluid through each of the ultrafiltration membrane units of less than thirty gallons per square foot per day limits the need for backwash cycles. A reduction in the number of backwash cycles enhances system autonomy and useful life, and limits the need for intervention for maintenance and component replacement.