An activated sludge process for the treatment of municipal wastewater, particularly applicable to oxidation ditch activated sludge treatment systems which utilize a conventional race track or continuous loop reactor basin configuration. The process removes phosphorus and nitrogen from an activated sludge wastewater treatment system, with an anoxic cycle followed by an aerobic cycle, and followed by a surface wasting cycle until a low flow diurnal period is reached in a diurnal or twenty-four hour period. Automated microprocessor control system using “oxidation-reduction potential” (ORP) and “dissolved oxygen” (DO) as process variable inputs automate aerated and anoxic cycles to optimize phosphorus and nitrogen removal using the available carbon in the influent wastewater resulting in an energy efficient dynamic dissolved oxygen control during the aerated periods.

Disclosed is an electrified membrane flow-cell reactor system and method for nitrogen wastewater treatment and upcycling towards ammonia nitrogen without external acid/base consumption. This electrified membrane flow-cell reactor includes a cathodic membrane module having a gas-permeable or gas-exchange membrane and a cathodic catalytic layer, an anode, and a semi-permeable membrane between the cathodic and anodic chamber. Three chambers in the flow-cell reactor include (i) a cathode chamber for nitrate reduction and upcycling towards NH.sub.3, (ii) a trap chamber for NH.sub.3 capture and storage, and (iii) an anode chamber for H.sup.+ production and protonation of gaseous NH.sub.3 to NH.sub.4.sup.+. The cathodic membrane and anode are connected to an electric power source to provide a stable cathodic potential and enable electrode reactions. This method will continuously treat nitrate-containing wastewater and achieve simultaneous electrochemical nitrate reduction from the wastewater and ammonia recovery as ammonium salts in the trap chamber.

Systems and methods are provided for nitrogen gas sparging assisted biological treatment of water. In one example, a denitrification system may include a media-packed column or bed through which nitrogen gas is sparged to remove dissolved oxygen from water. In some examples, an external carbon source and electron donor may be added to the media-packed column or bed to facilitate biological removal of the nitrate and/or other contaminants from the water. In this way, by relying on the sparged nitrogen gas to remove the dissolved oxygen, less of the external carbon source and electron donor may be employed as compared to denitrification systems not assisted by nitrogen gas sparging.

The disclosure relates to units, systems and methods for producing ammonia from a nitrogen-containing feedstock from sources like wastewater, ammonium nitrate solution, or an input gas containing one or more nitrogen-containing species, which can advantageously reduce carbon dioxide emissions, and energy consumption, as well as balance the nitrogen cycle.

Water treatment systems including electrically-driven and pressure-driven separation apparatus configured to produce a first treated water suitable for use as irrigation water and a second treated water suitable for use as potable water from one of brackish water and saline water and methods of operation of same.

A photocatalytic material for efficient photocatalytic removal of a high-concentration nitrate, and a preparation method and use thereof are disclosed. The preparation method includes the following steps: step 1: preparation of a citrate-stabilized silver nanoparticle; step 2: synthesis and functionalization modification of SiO.sub.2 step 3: preparation of Ag/SiO.sub.2; and step 4: preparation of an Ag/SiO.sub.2@cTiO.sub.2 core-shell structure. The photocatalytic material prepared by the present disclosure has high reduction catalytic activity and can quickly remove a high-concentration nitrate and achieve high nitrogen selectivity. In addition, due to protection of a titanium dioxide shell, the photocatalytic material has excellent stability and can remove a high-concentration nitrate in water when the nitrate coexists with a high-concentration chloride ion.

A solids dissociation apparatus that is used to remove various types of contaminants from a continuous fluid stream. The solids dissociation apparatus includes a housing. The solids dissociation apparatus also includes at least one insert that is operably engaged with the housing where the at least one insert is adapted to receive a continuous fluid stream. The solids dissociation apparatus also includes a transducer that is operably engaged with the housing and disposed about the at least one insert at a distance away from the at least one insert inside of the housing. The transducer is configured to create cavitation inside of the housing, via sonic waves, to eviscerate contaminants in the continuous fluid stream flowing through the at least one insert.

A solids separation apparatus (SSA) for removing solids concentrate from a continuous fluid stream. The solids separation apparatus includes a tower. The SSA includes a transducer operably engaged with a first end of the tower and configured to generate a standing sonic wave inside of the tower. The SSA also includes a reflector operably engaged with an opposing second of the tower and configured to reflect the standing sonic wave towards the transducer. The SSA also includes at least one set of ports defined in an interior wall of at least one solids removal stage of the tower. The at least one set of ports is positioned at anti-nodes of the standing sonic wave to recover solids concentrate from a fluid stream flowing through the tower. The transducer and the reflector of the SSA are linearly moveable relative to the tower to linearly move the standing sonic wave.

The invention is in the field of landfill leachate, in particular the invention is directed to a method for purifying landfill leachate comprising water, dissociated ions and organic compounds, wherein the method comprises providing the leachate in a eutectic freeze crystallization (EFC) crystallizer and carrying out eutectic freeze crystallization by reducing the temperature of the leachate to a first eutectic point to obtain a first mixture comprising ice and a first crystalline salt. Further the ice and the first crystalline salt are separated into an ice stream and a crystalline salt stream.

An object of the present invention is to provide a method for producing PHA, which is capable of suppressing the cost of overall production equipment including a waste water treatment process in production of PHA using microorganisms. Provided is a method including: a production step of purifying or molding polyhydroxyalkanoic acid biosynthesized in bacterial cells of a microorganism; a discharge step of discharging waste water containing nitrogen-containing impurities from the production step; and a nitrogen removal step of biologically treating the waste water to remove the nitrogen-containing impurities from the waste water. In the method, the residual ratio of the polyhydroxyalkanoic acid in the production step is 99% by weight or less, and the waste water that is biologically treated in the nitrogen removal step contains the polyhydroxyalkanoic acid in addition to the nitrogen-containing impurities.