NOVELTY - In a wastewater treatment plant, a waste stream contaminant removal system (1), comprises: a biological reactor for nitrification and denitrification of an incoming wastewater stream (11), where the biological reactor outputs wastewater effluent, wastewater effluent sludge (13) component, and gas stream having air, nitrous oxide, carbon dioxide and methane; a biological reactor gas output pipe channeling the gas stream to combustor; and a digester (20) receiving and processing wastewater effluent sludge component by means of an anaerobic sludge digestion process generating a methane gas.    USE - The waste stream contaminant removal system is useful in wastewater treatment plant (claimed).    ADVANTAGE - The waste stream contaminant removal system: eliminates nitrous oxide emissions to the atmosphere from the biological process; increases output from the combustion process due to increased oxygen; and reduces nitrogen oxide emissions from the combustion gas stream.    DETAILED DESCRIPTION - In a wastewater treatment plant, a waste stream contaminant removal system (1), comprises: a biological reactor for nitrification and denitrification of an incoming wastewater stream (11), where the biological reactor outputs a wastewater effluent, a wastewater effluent sludge (13) component, and a gas stream having air, nitrous oxide, carbon dioxide and methane; a biological reactor gas output pipe channeling the gas stream to a combustor; and a digester (20) receiving and processing the wastewater effluent sludge component by means of an anaerobic sludge digestion process generating a methane gas. The combustor has a combustion chamber (25) supplied by a mixing chamber, where the digester provides the digester methane gas to the mixing chamber, the methane gas is provided to the combustion chamber from the mixing chamber as a fuel source. The biological reactor gas output pipe channels the gas stream to the mixing chamber, where the gas stream is passed to the combustion chamber from the mixing chamber, and the gas stream methane is burnt as a supplemental combustion chamber fuel source. The nitrous oxide is thermally reduced down to nitrogen and oxygen at a temperature of 570F.    DESCRIPTION OF DRAWING(S) - The figure shows a functional block diagram of the process flow of a typical modified wastewater treatment plant.    Waste stream contaminant removal system (1)    Wastewater stream (11)    Sludge (13)    Digester (20)    Combustion chamber (25)