A water treatment system and a ballast water treatment method. A ballast water treatment system according to an embodiment of the present invention comprises: a first ballast water supply pipe for receiving a supply of ballast water from a first sea chest positioned in a non-explosion-proof area of a ship; an electrolytic bath for electrolyzing the ballast water supplied from the first ballast water supply pipe; a second ballast water supply pipe for receiving a supply of ballast water from a second sea chest, which is positioned in an explosion-proof area of the ship, and supplying the ballast water to a ballast tank of the ship; a filter provided to the second ballast water supply pipe so as to filter the ballast water passing through the second ballast water supply pipe; and a third ballast water supply pipe connected to the second ballast water supply pipe so as to supply the ballast water, which has been electrolyzed from the electrolytic bath, to the ballast water which has passed through the filter.

A biological reactor system treats concentrated contaminated water with a combination of upflow and downflow bioreactors that are downstream from a reverse osmosis or other concentrator. The system may have a fail safe configuration where flush water may be introduced to the reactors in the event of a power failure or when taking the reactors offline. Many reverse osmosis systems introduce antiscalant treatments upstream so that the reverse osmosis filters do not scale. However, such treatments result in superconcentrated conditions of the antiscalants in the contaminated water processed by the bioreactors. A flushing system may deconcentrate the bioreactors to prevent the antiscalants from precipitating and fouling the bioreactors.

Provided is a method for treating a hexavalent chromium-containing aqueous solution by water treatment employing a titanium dioxide photocatalyst that is excellent in both photocatalytic activity and solid-liquid separation performance. The method according to the present disclosure includes the steps of: adding catalyst particles to the aqueous solution; reducing hexavalent chromium by irradiating the aqueous solution with light having a wavelength of 200 nanometers or more and 400 nanometers or less while stirring the catalyst particles in the aqueous solution; and stopping the stirring and separating the catalyst particles from the aqueous solution by sedimentation. Each catalyst particle is composed only of a titanium dioxide particle and a zeolite particle, the titanium dioxide particle is adsorbed on the outer surface of the zeolite particle, the zeolite particle has a silica/alumina molar ratio of 10 or more, and the catalyst particles are contained in the aqueous solution at a concentration of 0.4 grams/liter or more and 16 grams/liter or less.

Provided is a method for treating a hexavalent chromium-containing aqueous solution by water treatment employing a titanium dioxide photocatalyst that is excellent in both photocatalytic activity and solid-liquid separation performance. The method according to the present disclosure includes the steps of: adding catalyst particles to the aqueous solution; reducing hexavalent chromium by irradiating the aqueous solution with light having a wavelength of 200 nanometers or more and 400 nanometers or less while stirring the catalyst particles in the aqueous solution; and stopping the stirring and separating the catalyst particles from the aqueous solution by sedimentation. Each catalyst particle is composed only of a titanium dioxide particle and a zeolite particle, the titanium dioxide particle is adsorbed on the outer surface of the zeolite particle, the zeolite particle has a silica/alumina molar ratio of 10 or more, and the catalyst particles are contained in the aqueous solution at a concentration of 0.4 grams/liter or more and 16 grams/liter or less.

The present embodiments generally relate to methods and compositions for the removal of selenium from a fluid in need of treatment, such as, for example, industrial wastewaters. The methods and compositions for the removal of selenium generally comprise the use of one or more coagulants, such as at least one iron-containing coagulant, and one or more reducing agents, such as at least one sodium sulfite-based reducing agent.

A system for treatment of a polluted effluent, includes an outer chamber configured to treat the polluted effluent in mixture with a purification slurry including particles of one or more catalysts and/or organoclays, or a mixture thereof. The outer chamber includes (i) a stirring unit consisting of an engine and a stirrer, configured to mix the polluted effluent and the purification slurry to prevent the particles from sinking without causing a turbulence, (ii) a membrane located at the top of the outer chamber through which a treated effluent passes, while preventing the particles of one or more catalysts and/or organoclays from exiting the outer chamber together with the treated effluent, (iii) a membrane cleaning system configured to remove and collect the particles of one or more catalysts and/or organoclays accumulated on the membrane, and re-introducing the particles back to the bottom of the outer chamber.

A reduction treatment agent made of a powder with a particle size within a range of 1500 to 3000 mesh, the powder containing: 20 to 40 parts of a mixed-oxide powder containing magnesium oxide and zinc oxide; and 60 to 80 parts of an organic acid powder containing calcium, ascorbic acid, citric acid and salt. The reduction treatment agent may further contain one to six kinds of metal powder selected from the group of copper, molybdenum, nickel, cobalt, iron and aluminum, each in an amount of one part. Due to this configuration, the reduction treatment agent can be easily mixed with various substances when added to those substances. Even if the target substance is not water, the agent can entirely and uniformly change that substance into a reduced state. Additionally, the reduction treatment agent can act as a surfactant, and therefore, can be used as cosmetics or food.

A carbon structure comprising a mixture and a polymer. The mixture has a base carbon and a catalytic carbon. The polymer has a first binder with a median diameter of less than 10 microns and a second binder with a median diameter between 10 and 70 microns.

A carbon structure comprising a mixture and a polymer. The mixture has a base carbon and a catalytic carbon. The polymer has a first binder with a median diameter of less than 10 microns and a second binder with a median diameter between 10 and 70 microns.

The present disclosure relates to sulfur-treated zerovalent iron nanoparticles and the use of same for transforming chlorinated solvent pollutants and may therefore be useful as water treatment technology for restoration of groundwater resources contaminated with toxic, chlorinated solvent pollutants.