The present application relates to a system for removal of nitrate from water. The system includes a first reactor comprising a porous oxide-derived silver electrode (OD-Ag) for electrocatalytic reduction of nitrate (NO.sub.3.sup.?) to nitrite (NO.sub.2.sup.?) and a second reactor comprising a Pd-based catalyst for catalytic reduction of nitrite (NO.sub.2.sup.?). Also disclosed is a method of removing nitrate from water.

The water treatment method is for treating water to be treated that contains organic matter and a nitrogen component, and includes, in a biological treatment device including at least an aerobic tank: a biological treating for biologically treating inflowing water to be treated aerobically by using sludge that contains granules; a solid-liquid separating for separating the biological treatment solution in the aerobic tank into treated water and concentrated sludge using a solid-liquid separation device; and a sludge returning for returning the concentrated sludge obtained in the solid-liquid separating to a stage before the biological treatment device. The concentration of ammonium nitrogen remaining due to the nitrification reaction in the aerobic tank is measured with an ammonium nitrogen concentration measurement device, and the amount of gas containing oxygen dispersed to the aerobic tank is controlled with a blower so that the measured ammonium nitrogen concentration is within a prescribed range.

The present invention relates to a method for recycling supercritical waste liquid generated during a process of producing a silica aerogel blanket, and a method for producing a silica aerogel blanket reusing supercritical waste liquid recycled thereby. More particularly, the present invention provides a method for recycling supercritical waste liquid and a method for producing a silica aerogel blanket capable of reducing the production costs and preventing the deterioration in thermal insulation performance of a silica aerogel blanket by adding a metal salt to the supercritical waste liquid by the recycling method.

An integrated method for clearance, collection and capture of internal pollutants and algae at the bottom of a lake include the following steps: selecting areas where the pollution level is high, and organic or inorganic particulate matter is prone to accumulation and carrying out trenching operations at the bottom of the lake to form a plurality of traps; and removing the sludge and algae inside the traps and clearing the sediment inside the traps, for subsequent internal pollution control when the surface-layer sludge on both sides of the traps almost fills up the traps. This method makes use of the hydrodynamic disturbances of waves formed by natural wind energy and lake currents to continuously transport sludge with a high pollution level and a small specific gravity and algae in the surface layer of the lake bottom, which are rich in organic debris, to artificially built traps.

The present invention belongs to the technical field of water treatment, and in particular to a magnetic powder strengthened method for removing nitrate nitrogen and inorganic phosphorus, which includes the following steps: (1) mixing permanent magnetic material powder with paramagnetic Fe3O4 powder, and magnetizing the mixture in a magnetic field to prepare magnetic powder; (2) adding the magnetic powder directly or in a form of granular filler into a water treatment reaction vessel; and (3) allowing the to-be-treated water to enter the water treatment reaction vessel, performing a chemical reaction of removing nitrate nitrogen and inorganic phosphorus in the presence of a reducing agent, and discharging the water after the reaction is completed. By adopting the method of the present invention, a uniform and fine magnetic field can be provided, thus the reaction efficiency is improved, and the process is simplified and the cost is lowered.

Carbonaceous material that is activated to form precursor activated carbon is further enhanced by doping with iron and nitrogen and calcining. The resultant sorbent material has excellent catalytic properties which are useful in the field of fluid purification. The further enhancement can be performed in a single stage process or a dual stage process. The carbonaceous material includes those obtained from coal, wood, or coconut shells. The described treatment processes result in a sorbent material that has excellent performance in removing chloramine and similar compounds from fluids such as water that is intended for drinking.

Carbonaceous material that is activated to form precursor activated carbon is further enhanced by doping with copper, iron, and nitrogen and calcining. The carbonaceous material includes those obtained from coal, wood, or coconut shells. Methods of doping the activated carbon are described. The described treatment processes result in a sorbent material that has excellent performance in removing chloramine and similar compounds from fluids such as water that is intended for drinking.

A wastewater treatment device has: an ozone generator which supplies ozone; a mixer which mixes ozone supplied from the ozone generator with wastewater and supplies ozone mixed wastewater; an ozone oxidation unit which progresses ozone oxidation in the ozone mixed wastewater while passing the ozone mixed wastewater therethrough and discharges wastewater in which the ozone has been consumed; a biological treatment unit which performs biological treatment on the wastewater discharged from the ozone oxidation unit using microorganisms; and an adjusting device which adjusts the amount of ozone to be mixed with the wastewater by the mixer so that ozone in an amount that inhibits the microorganisms of the biological treatment unit does not remain in the wastewater discharged from the ozone oxidation unit.

A method for advanced nitrogen and phosphorus removal in sewage treatment includes the following steps: feeding raw water and return sludge into a pre-denitrification zone for denitrification; allowing a sludge-containing mixed liquor discharged from the pre-denitrification zone to enter an anaerobic zone to undergo a biological phosphorus removal reaction; allowing a sludge-containing mixed liquor discharged from the anaerobic zone and a return nitrification liquid to enter an anoxic zone for denitrification; allowing a sludge-containing mixed liquor discharged from the anoxic zone to enter an aerobic zone for nitrification and excessive phosphorus uptake, and allowing part of a nitrification liquid to be returned to the anoxic zone; allowing a sludge-containing mixed liquor discharged from the aerobic zone to enter a sedimentation zone for separation; passing a resulting supernatant through a biological filtration zone; returning part of resulting sludge to the pre-denitrification zone; and the like.

The application belongs to the technical field of water treatment, and relates to a biofilm electrochemical reactor for simultaneously removing nitrate nitrogen and trace organic matters in water. According to the principles of electrochemical reaction and products completely different under different cathode and anode material conditions, the reactor is divided into three functional regions, wherein first, an electrochemical reaction of producing hydrogen at a cathode and decomposing carbon at an anode is realized in a first functional region so as to provide a condition for reduction of nitrate nitrogen by a hydrogen autotrophic denitrifying bacteria of a particle electrode layer in a second functional region, after products generated by means of the electrochemical reaction and a biochemical reaction in the previous two functional regions enter a third functional region, pollutants such as trace organic components and residual ammonia nitrogen in water are oxidized and decomposed by using anodic oxidation function.