NOVELTY - Removing (1) methane from biogas comprises: receiving biogas including methane and other components into a first tank; receiving water into the first tank; contacting the biogas with the water inside the first tank; dispensing methane gas from an outlet of the first tank; and producing an effluent stream that includes other components of the biogas, from the tank.    USE - The methods are useful for treating wastewater, removing methane from biogas, and removing byproduct gases after aerobic digestion (all claimed), which is useful to generate energy i.e. electricity.    ADVANTAGE - The method: effectively and rapidly treats wastewater; generates clean energy and promotes production of useful downstream products from the harmful byproducts; reduces the nutrient load by actively removing biological matter remaining in the effluent; and stabilizes the wastewater i.e. lowers biochemical oxygen demand levels and solid content, increases or maintains dissolved oxygen levels in wastewater throughout the various stages, and avoids reversible reaction.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) removing (2) byproduct gases after aerobic digestion, comprising: receiving into a first tank a gaseous mixture including at least one of ammonia gas and sulfur gas; receiving water into the first tank; contacting the gaseous mixture with the water inside the first tank to produce an effluent stream of water having dissolved aqueous ammonia or sulfur in it, and produce a residual gaseous mixture including at least one of residual ammonia gas and residual sulfur gas; dispensing residual gas; and discharging the effluent stream including water which has dissolved aqueous ammonia or sulfur in it;    (2) a system (A) for removing byproducts of anaerobic digestion, comprising a first tank including: a first inlet that is connected to receive byproduct gases of anaerobic digestion including at least one gas and methane; a first outlet that provides methane gas as exhaust; a second inlet that is connected to receive a stream of water; and a second outlet that discharges an effluent water stream having dissolved gas in it, into a tank designed for removing solids; and an electrical generator that is connected to the first outlet of the first tank, where the first tank is designed to contact the stream of water with the byproduct gases of anaerobic digestion and produce the effluent stream of water having dissolved gas in it;    (3) a system (B) (100) for wastewater treatment, comprising: a solids-removal subassembly designed to remove solids from wastewater and produce solids-depleted water; an assembly designed for processing organic material in the solids-depleted wastewater to produce treated water and the assembly connected to the solids-removal subassembly; and a tank that has a first inlet, first outlet and second outlet, where the first inlet of the tank is designed to receive treated water, the first outlet is designed to discharge a first portion of treated water, the second outlet is designed to discharge a second portion of treated water, and the first portion of treated water is used for processing byproduct gases resulting from wastewater treatment; and    (4) method (3) for treating wastewater comprising: removing solids from wastewater to produce solids-depleted water; processing organic material in the solids-depleted wastewater to produce treated water; discharging a first portion of treated water and a second portion of treated water; and using the first portion of treated water to processes byproduct gases resulting from wastewater treatment.    DESCRIPTION OF DRAWING(S) - The figure shows a system for wastewater treatment.    System (100)    Diffused air flotation tank (106)    Sedimentation removal tank (108)    Biological chip reactor (110, 112)    High-rate algal pond (118)