TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method (1) further comprises: carrying out anaerobic digestion of water enriched with organic matter in a second tank, to produce the biogas; sending the effluent stream from the tank to a diffused air flotation tank (106) designed to effect removal of solids; and sending the methane gas to an electrical generator that is designed to burn the methane gas and produce electrical energy. In the method (1), the step of contacting includes passing bubbles of biogas through the water. The electrical generator produces exhaust gases which include at least one of carbon dioxide gas, sulfur oxide (SOx) gas and nitrogen oxide (NOx) gas and are treated in a third tank by contacting the exhaust gases with water to remove the exhaust gas from the third tank and produce water having dissolved exhaust gas. The water having dissolved exhaust gas is delivered to an algal pond (118). In the method (1), the step of contacting includes passing bubbles of gaseous mixture through the water. The method (2) further comprises: carrying out aerobic digestion of wastewater in a second tank to produce the gaseous mixture including aqueous ammonia or sulfur; and detecting concentration of ammonia by volume in the effluent stream, and conveying an effluent stream including water which has dissolved aqueous ammonia or sulfur, to a tank which either breaks down ammonia or consumes sulfur gas (if amount of ammonia in the effluent water stream is greater than or equal to predetermined value), or conveying the effluent stream to an algal pond (if amount of ammonia in the effluent stream is less than the predetermined value), where the predetermined value is 0-10 ppm. In the method (2), the step of dispensing includes recirculating the residual gaseous mixture from outlet of the first tank to an inlet of the first tank. In the system (A), the first outlet is communicatively coupled to the first inlet such that the residual gas is provided back to the second tank. The method (3) further comprises: removing nutrients from wastewater; conducting anaerobic digestion in an anaerobic digestion tank to produce the byproduct gases including methane and at least one gas, and contacting in a first tank a first amount of the first portion of treated water with the byproduct gases to produce methane exhaust and treated water having dissolved gas in it; conveying methane to an electrical generator and producing electricity and the gases; contacting in a second tank a second amount of the first portion of treated water with the gases to produce treated water having dissolved gas and a residual gas in it; sending the treated water having dissolved gas to an algal pond, and recirculating back the residual gas to the second tank; conducting aerobic digestion in presence of biological chips and producing the byproduct gases, and contacting in a tank a first portion of the treated water with the byproduct gases to produce treated water and produce a residual gas; and conveying to an algal pond the treated water including aqueous ammonia or sulfur (if the amount of ammonia in the treated water is less than a predetermined value), or conveying to the biological chip reactor (110, 112) the treated water (if the amount of ammonia in the treated water is greater than or equal to predetermined value), where the predetermined value is 0-10 ppm. The step of using the first portion of the treated water is carried out after removing the nutrients. Preferred Components: The organic matter in the water is 0.5-25 vol.%. The water is purified water, which is obtained from a wastewater treatment facility. The content of organic matter in the wastewater after aerobic digestion is 0-4 vol.%. The algal pond is a high-rate algal pond (118). The aerobic digestion is carried out in a biological chip reactor. In the system, the electrical generator produces electricity and a gas including carbon dioxide, sulfur oxide (SOx) or nitrogen oxide (NOx). The system (A) further comprises a second tank which includes: a first inlet that is connected to receive the gas produced in the electrical generator; a first outlet that is designed to dispense a residual gas; a second inlet that is configured to receive a stream of water; and a second outlet that is designed for discharging water which has dissolved gas, where the second tank is configured to contact the stream of water with the gas to produce the effluent water having dissolved gas and produce the residual gas. In the system (A), the second outlet of the second tank is connected to an algal pond. In the system (B), the tank is: a nutrient removal tank designed to remove nutrients from wastewater; and a holding tank that is located downstream from a nutrient removal tank which is designed to remove nutrients from wastewater. In the system (B), the solids-removal subassembly includes at least one of: a solids separator; a dissolved air flotation device which includes a pored diffuser, and a high-pressure water pump fitted with a venturi tube for drawing in air, for forming air bubbles and for forcing the air bubbles through the pore diffuser to form micro-air bubbles in wastewater; and a first sedimentation removal tank (108) designed to remove solids from wastewater using diffused air flow which maintains dissolved oxygen in wastewater at a constant level. The assembly designed for processing organic material in the solids-depleted wastewater includes at least one biological chip reactors or an aerobic sludge digester. The system for wastewater treatment further comprises: an anaerobic tank to carry out anaerobic digestion, where a first amount of the first portion of treated water is used to process the byproduct gases including methane and at least one other gas resulting from anaerobic digestion; a first tank which is designed to contact the byproduct gases including methane gas and at least one other gas with the first amount of the first portion of treated water to produce methane exhaust and effluent water having dissolved at least one other gas in it; an electrical generator, and a first connection which is designed to connect to the first tank with electrical generator such that methane exhaust from the first tank is conveyed to the electrical generator to produce electricity and produce the gas; second tank which is designed to contact a second amount of the first portion of water with the gas to produce water having dissolved gas, and produce a residual gas; an algal pond which is designed to receive water having dissolved gas in it; a third tank which is designed to contact a first portion of water with the byproduct gases including ammonia or sulfur gas that is generated during aerobic digestion of wastewater.