In an apparatus for treating wastewater, e.g sewage water, the water passes through a standard treatment process stream to promote production of dissolved reactive phosphate ions (PO4). Iron (or aluminum) ions are generated by electrochemical means and added to the process stream at one or more locations to produce metal-P coagulant solids removed in part by pump-out, with the substantial remaining P removed by mineralization and filtration in a biological filter such as a sand filter or leach field. In another apparatus, the water passes through a standard aerobic treatment process stream to promote production of dissolved reactive phosphate ions. Iron (or aluminum) ions are generated by electrochemical means and added to the process stream at one or more locations to produce a flocculant of Fe—P minerals that are separated out by sedimentation, physical filtration or magnetic means.

A method is disclosed for nitrogen recovery from an ammonium including fluid and a bio-electrochemical system for the same. In an embodiment, the method includes providing an anode compartment including an anode; providing a cathode compartment including a cathode, wherein the compartments are separated by at least one ion exchange membrane; providing the ammonium comprising fluid in the anode compartment and a second fluid in the cathode compartment; applying a voltage between the anode and the cathode; and extracting nitrogen from the cathode compartment.

A nitrate reduction method includes the step of reducing at least one type selected from a group of nitrates and nitrites at an active site included in a defect of graphene in a reduction reaction, wherein the graphene is a reduced product of graphene oxide, and the defect of the graphene is derived from a defect of the graphene oxide.

A process for enhanced anaerobic digestion of sludge by alcoholization of food waste, comprising steps of: (1) ethanol prefermentation of food waste—feeding the food waste having been crushed into a uniform grain size into an ethanol production reactor, where the food waste is subjected to rapid and efficient anaerobic fermentation activated by addition of yeast and pH adjustment to produce ethanol and obtain a fermentation broth and a fermentation residue; (2) sludge pretreatment—pretreating the sludge after mixing with the fermentation residue; and (3) methanogenesis of anaerobic digestion—subjecting products resulting from the sludge pretreatment to be mixed with the fermentation broth and then to methanogenesis of anaerobic digestion in a methane production reactor. With this process, the sludge and the food waste can be treated efficiently via multi-phase reactions, and the resource recovery and biogas quality can be enhanced.

There are provided processes for treating wastewater. The processes can comprise treating a mixture comprising the wastewater and an activated sludge, in a single reactor, with an electric current having a density of less than about 55 A/m.sup.2, by means of at least one anode and at least one cathode that define therebetween an electrical zone for treating the mixture; exposing the mixture to an intermittent ON/OFF electrical exposure mode to the electric current in which an OFF period of time is about 1 to about 10 times longer than an ON period of time; and maintaining an adequate oxidation-reduction potential in the single reactor. Such processes allow for substantial removal of carbon, nitrogen and phosphorus from the wastewater in the single reactor of various forms and for obtaining another mixture comprising a treated wastewater and solids.

Wastewater containing organic matter may be treated using a multi-zone apparatus. In a first zone, organic matter in the wastewater may, among other things, be converted to at least volatile fatty acids (VFAs) and, thereafter, a portion of the treated wastewater may flow to a second zone that may, among other things, convert the VFAs to methane.

A combined waste water and gas treatment system for efficiently decarbonizing and removing nitrogen, including a water feeding pump, a carbon capture device, an intermediate water tank, and an anaerobic ammonium oxidation reactor connected in sequence through pipelines, where the carbon capture device includes an anode chamber and a cathode chamber; an anode plate is arranged in the anode chamber; a cathode plate is arranged in the cathode chamber; a gas inlet pipe is further arranged at the cathode chamber; an air compressor is connected with the gas inlet pipe; a gas outlet pipe is arranged at a top of the carbon capture device; a water outlet in the intermediate water tank is fluidly communicated with a bottom end of the anaerobic ammonium oxidation reactor through a second water inlet pipe; the gas outlet pipe is fluidly communicated with the second water inlet pipe.

A system for biological nitrogen removal and negative carbon discharge from wastewater with low carbon-to-nitrogen ratio may include a water intake pump, a carbon capture apparatus, a carbon recovery sedimentation tank, an integrated ammonium apparatus, an autotrophic denitrification apparatus and a denitrification sedimentation tank that are connected in sequence by pipes. The carbon capture apparatus may include an anode chamber communicated with the water intake pump via a water inlet pipe and a cathode chamber communicated with the carbon recovery sedimentation tank via a first water outlet pipe. The anode and cathode chambers may be spaced apart by an ion exchange resin membrane. The anode and cathode chambers may be provided with an anode plate and a cathode plate electrically connected to positive and negative electrodes of a power source, respectively. A bottom of the cathode chamber may be provided with aerators connected to a first air compressor by a pipe.

The present disclosure generally relates to a system for monitoring and/or controlling one or more agents, such as cleaning agents, in a wastewater treatment system. The system comprises a bio-electrochemical sensor for monitoring metabolic activity of a population of exo-electrogenic bacteria and providing an electrical output corresponding with the metabolic activity, where the bio-electrochemical sensor comprises an electrode pair and a power source for delivering a voltage across the electrode pair, and an electrical output analyzer for analyzing the electrical output and correlating the electrical output with the one or more agents in the wastewater treatment system. a change in electrical output beyond a threshold indicates that an adjustment in the delivery of the one or more agents is needed. a method and sensor for monitoring and/or controlling a cleaning process in a wastewater treatment system are also provided. The system, method, and sensor disclosed herein are particularly useful for cleaning membranes incorporated in a wastewater treatment process.

The invention is directed to a process to prepare elemental sulphur by (i) contacting an aqueous solution comprising bisulphide with oxidised sulphide-oxidising bacteria under anaerobic conditions wherein elemental sulphur is produced and a reduced sulphide-oxidising bacteria is obtained and (ii) wherein the reduced sulphide-oxidising bacteria are oxidised by transfer of electrons to an anode of an electrochemical cell to obtain the oxidised sulphide-oxidising bacteria.