A gas treatment apparatus, comprising: a gas scrubber chamber operable to receive an effluent gas stream originating from a manufacturing process tool to be scrubbed therewithin to provide a scrubbed gas stream; and an electrostatic precipitation chamber operable to receive said scrubbed gas stream to be treated therewithin to provide a treated gas stream, said electrostatic precipitation chamber defining a first chamber and said gas scrubber chamber defining a second chamber, said first chamber being configured to concentrically surround said second chamber, wherein said first chamber and said second chamber share a common wall, an inner surface of said common wall defining an outer wall of said second chamber and an outer surface of said common wall defining an inner wall of said first chamber; said second chamber comprising an elongate chamber defined by said inner surface of said common wall and said first chamber comprising an elongate annular chamber defined by said outer surface of said common wall and an inner surface of an enclosing wall; wherein said electrostatic precipitation chamber comprises an elongate annular electrode structure located between said outer surface of said common wall and said inner surface of said enclosing wall, and outlets for ejecting liquid to provide a circumferentially flowing liquid curtain along both said outer surface of said common wall and said inner surface of said enclosing wall; wherein said gas scrubbing chamber comprises a header tank at least partially defining said gas scrubbing chamber and comprising a sieve plate, said header tank being operable to provide a constant flow of a received liquid to said gas scrubbing chamber through said sieve plate and provides the liquid curtain which flows down the outer surface of the common wall; wherein said gas scrubbing chamber comprises an effluent gas stream inlet for receiving said effluent gas stream and a conduit to convey said scrubbed gas stream to an inlet of said electrostatic precipitation chamber located away from a suspension structure for said elongate annular electrode structure, said electrostatic precipitation chamber comprising an treated gas stream outlet for providing treated gas stream, said effluent gas stream inlet and said treated gas stream outlet being positioned to cause gas flow along an axial length of both said gas scrubbing chamber and said electrostatic precipitation chamber. a gas scrubber chamber operable to receive an effluent gas stream originating from a manufacturing process tool to be scrubbed therewithin to provide a scrubbed gas stream; and an electrostatic precipitation chamber operable to receive said scrubbed gas stream to be treated therewithin to provide a treated gas stream, said electrostatic precipitation chamber defining a first chamber and said gas scrubber chamber defining a second chamber, said first chamber being configured to concentrically surround said second chamber, wherein said first chamber and said second chamber share a common wall, an inner surface of said common wall defining an outer wall of said second chamber and an outer surface of said common wall defining an inner wall of said first chamber; said second chamber comprising an elongate chamber defined by said inner surface of said common wall and said first chamber comprising an elongate annular chamber defined by said outer surface of said common wall and an inner surface of an enclosing wall; wherein said electrostatic precipitation chamber comprises an elongate annular electrode structure located between said outer surface of said common wall and said inner surface of said enclosing wall, and outlets for ejecting liquid to provide a circumferentially flowing liquid curtain along both said outer surface of said common wall and said inner surface of said enclosing wall; wherein said gas scrubbing chamber comprises a header tank at least partially defining said gas scrubbing chamber and comprising a sieve plate, said header tank being operable to provide a constant flow of a received liquid to said gas scrubbing chamber through said sieve plate and provides the liquid curtain which flows down the outer surface of the common wall; wherein said gas scrubbing chamber comprises an effluent gas stream inlet for receiving said effluent gas stream and a conduit to convey said scrubbed gas stream to an inlet of said electrostatic precipitation chamber located away from a suspension structure for said elongate annular electrode structure, said electrostatic precipitation chamber comprising an treated gas stream outlet for providing treated gas stream, said effluent gas stream inlet and said treated gas stream outlet being positioned to cause gas flow along an axial length of both said gas scrubbing chamber and said electrostatic precipitation chamber.