NOVELTY - A vessel to float on a body of seawater comprises a wastewater treatment system (415) comprising a wastewater (410) intake port, a wastewater treatment component, and a treated wastewater conduit; a desalination system (416) containing a seawater intake, a desalination component, and a desalinated water (478) discharge port; a mixing system for mixing the treated wastewater from the wastewater treatment system with concentrate from the desalination system; and a wastewater discharge system.    USE - As a vessel to float on body of wastewater for treating wastewater to form treated wastewater, sludge used as fertilizer, combustible gas e.g. methane that is converted into electricity; can be used in combination with desalination and power generation components. The sludge resulting from wastewater treatment can be transferred to a land-based facility for further processing, disposal, or use (e.g., as agricultural fertilizer), e.g., a tugboat drawn barge can be used as a transfer vessel to transfer treated sludge from an apparatus positioned in a body of seawater to a land-based sludge disposal/distribution facility. The fuels include biofuels (e.g., fuels such as ethanol or methanol that are produced at least in part from biomass such as plants, straw, or biomass waste streams); petroleum-based fuels such as diesel fuel, jet fuel, kerosene, and gasoline; gases such as propane or natural gas; and liquefied coal products.    ADVANTAGE - By positioning components of the wastewater (WW) operation offshore, the need for expensive shore-side land is reduced and any unpleasant odors are minimized. The vessel provides several innovations to reduce the impact of the WW treatment on the marine environment including the pre-dilution of the WW treatment end products prior to discharge into a body of seawater, plankton avoidance equipment, and having intake and discharge at different depths. The vessel treats at least 75 (preferably at least 600) millions liters of wastewater per day. The apparatus can be self-propelled, non-self propelled, manned, or unmanned, but is preferably a sea-going vessel because of mobility and ease of construction (i.e., the vessel can be built at any suitable shipyard in an industrialized country and moved from the shipyard to the place of use).    DETAILED DESCRIPTION - A vessel to float on a body of seawater comprises a wastewater treatment system (415), a desalination system (416), a mixing system, and a wastewater discharge system. The wastewater treatment system comprises a wastewater (410) intake port for intaking wastewater onto the vessel; a wastewater treatment component for treating the wastewater to produce treated wastewater and sludge; and a treated wastewater conduit for transporting the treated wastewater away from the wastewater treatment component. The desalination system comprises a seawater intake for intaking seawater from the body of seawater onto the vessel; a desalination component for desalinating the seawater to produce concentrate and desalinated water; and a desalinated water discharge port for transferring the desalinated water from the vessel. The mixing system comprises a mixing tank for mixing the treated wastewater from the wastewater treatment system with the concentrate from the desalination system. The wastewater discharge system discharges the treated wastewater and concentrate mixture into the body of seawater. The vessel further comprises a sludge treatment component for treating the sludge, a sludge transferring element for transferring the sludge from the vessel, a power generation system. The mixing tank is configured to receive seawater from the seawater intake such that the treated wastewater and concentrate mixture is diluted with the seawater before being discharged into the body of seawater. The wastewater discharge system comprises a member extending down from the vessel with a several discharge ports disposed on the member. The power generation system produces electricity to run the wastewater treatment system, where the power generation system comprises an electricity transfer cable for transferring at least some of the electricity generated by the power generation system is delivered to land; and to run the desalination system, where the power generation system comprises an electricity transfer cable for transferring at least some of the electricity generated by the power generation system to land.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the apparatus/vessel to float on a body of seawater for treating wastewater.    Wastewater (410)    Wastewater treatment system (415)    Desalination system (416)    Desalinated water (478)    Land-based electricity distribution center (494)