The invention relates to a method for treating wastewater in an activated sludge process, which comprises a biological treatment step followed by a sedimentation step for separation of sludge and treated effluent water. The method comprises directing a part of the treated effluent water as a backflow from the sedimentation step to the biological treatment step, the backflow having an original pH value; adjusting the backflow pH from the original pH value to a first pH value between the sedimentation step and the biological treatment step, and adding a coagulant and/or an oxidant to the backflow after the adjustment of the backflow pH to the first pH value and before backflow's entry to the biological treatment step.

A treatment system and method for cephalosporin wastewater are disclosed. The treatment system includes: a flocculation and sedimentation device, an alkali reaction tank, a PAC reaction tank, a PAM reaction tank, a wastewater heat exchanger, a wastewater heater and an oxidation reactor that are connected with each other in sequence, wherein the wastewater heat exchanger is provided with a material inlet, a material outlet, a heat source inlet and a heat source outlet. An oxidized water from the oxidation reactor enters the wastewater heat exchanger from the heat source inlet, the heat source outlet is connected with a product canister, the product canister is connected with a membrane filtration device to realize concentration treatment of a landfill leachate, the material inlet is connected with the PAM reaction tank, and the material outlet is connected with the wastewater heater. An outer side of the oxidation reactor is provided with a micro-interfacial generation system for dispersing and breaking a gas into bubbles. The treatment system of the prevent invention improves the contact of reaction phase interfaces after arranging the micro-interfacial generation system, which ensures a good wastewater treatment effect under relatively mild operating conditions.

A ultrapure water supply system 10 includes a pure water tank 16 provided vertically below a use point 30, a return pipe 32 through which ultrapure water is returned from the use point 30 to the pure water tank 16, a first pressure regulating valve 40 that is provided at a first position H1 of the return pipe 32 and adjusts a first pressure upstream of the first position H1 and a second pressure regulating valve 42 that is provided at a second position H2 downstream of the first position H1 and vertically below the first position H1 of the return pipe 32 and adjusts a second pressure downstream of the first position H1 and upstream of the second position H2.

A combined water aeration and filtration unit (WAFU), having a tank with a vent section at a top of said WAFU and above an aeration section above a filtration section at a bottom of said WAFU. The vent section has one or more demisters and one or more vents for detraining water and providing a dry air exit from said WAFU. The air section has a water inlet ending in a spray nozzle near the top of the aeration section to turn incoming dirty water into water droplets and a forced air blower on a side or top of the aeration section for blowing air through said water droplets in rate sufficient to remove volatile organic compounds and precipitate manganese and iron. The aeration section also has one or more annular rings or partially annular baffles on an inside wall of the tank to force water from said inside wall into an interior of the tank. Thus, no water escapes aeration. A backwash collection trough and backwash water outlet are positioned above the filtration section for removing dirty backwash water from the unit. The filtration section has one or more filters therein and a drain and clean water outlet near its bottom for egress of clean water from said WAFU.

A combined water aeration and filtration unit (WAFU), having a tank with a vent section at a top of said WAFU and above an aeration section above a filtration section at a bottom of said WAFU. The vent section has one or more demisters and one or more vents for detraining water and providing a dry air exit from said WAFU. The air section has a water inlet ending in a spray nozzle near the top of the aeration section to turn incoming dirty water into water droplets and a forced air blower on a side or top of the aeration section for blowing air through said water droplets in rate sufficient to remove volatile organic compounds and precipitate manganese and iron. The aeration section also has one or more annular rings or partially annular baffles on an inside wall of the tank to force water from said inside wall into an interior of the tank. Thus, no water escapes aeration. A backwash collection trough and backwash water outlet are positioned above the filtration section for removing dirty backwash water from the unit. The filtration section has one or more filters therein and a drain and clean water outlet near its bottom for egress of clean water from said WAFU.

The disclosure discloses a production method for full resource recycling of sulphate-process titanium dioxide production wastewater. The method comprises the steps: adding sulphate-process titanium dioxide production wastewater neutralized with lime and treatment wastewater obtained by separating gypsum in a filter press into a recycled sodium carbonate solution to precipitate saturated calcium sulfate in the treatment wastewater, clarifying slurry to separate a calcium carbonate precipitate from a sodium sulfate solution, and performing membrane separation on the separated sodium sulfate solution in a membrane filter; and adding lime into the concentrated phase sodium sulfate solution for causticizing reaction, wherein the filtrate is used as a sodium hydroxide solution, carbonizing using a carbon dioxide-containing tail gas produced in the production process of titanium dioxide to obtain a sodium carbonate solution, and then precipitating saturated calcium sulfate in the treatment wastewater again.

Disclosed are methods of treating wastewater using a membrane bioreactor and achieving a target phosphorus concentration for the membrane permeate stream. These methods include the steps of dosing a wastewater stream with a rare earth clarifying agent and passing the dosed wastewater stream through the membrane to obtain a membrane permeate stream with a permeate concentration that is less than the phosphorus concentration of the influent stream. This permeate concentration also can be equal to or less than a target phosphorus concentration. In the methods as disclosed herein, the rare earth clarifying agent can be chloride salts of one or more rare earth elements and in certain embodiments, the rare earth clarifying agent can be CeCl.sub.3 and LaCl.sub.3.

A system and method for generating base water and precipitate, including combining produced water with seawater to precipitate barium sulfate from barium in the produced water and from sulfate in the seawater, and separating the precipitate to give the base water and the precipitate. The base water may have less than a specified amount of sulfate and be utilized for hydraulic fracturing fluid. The precipitate may give a weighting agent for drilling.

Wastewater processing modules that include an interior surface defining an interior volume, one or more inlets configured to receive wastewater into the interior volume, one or more outlets configured to exhaust processed water from the interior volume, one or more flow-deflecting baffles positioned within the interior volume fluidly between the inlet(s) and the outlet(s) and that divide the interior volume into a plurality of fluidly connected sections, and a purification medium at least partially filing the plurality of fluidly connected sections. The flow-deflecting baffle(s) are configured to channel the wastewater to flow along a plurality of circuitous bulk flow paths through the purification medium. The purification medium is configured to sequester contaminants from the wastewater as it flows through the interior volume along the circuitous bulk flow paths to produce the processed water therefrom.

One aspect of the present invention is directed to a granular filter media for removing contaminants from water or other liquids. The media comprise granular materials comprising aggregate and remediation materials. Other aspects of the invention are directed to methods of making and using the granular filter media of the invention.