A compound having the following structure:

##STR00001##

wherein: R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are independently selected from (i) hydrogen atom, (ii) hydrocarbon groups (R) containing 1-30 carbon atoms and optionally substituted with one or more fluorine atoms, (iii) —OR′ groups, (iv) —NR′.sub.2 groups, (v) —C(O)R′ groups, and (vi) halogen atoms, wherein R′ groups are independently selected from R groups and hydrogen atoms, and wherein the R group optionally includes a C(O), ether, or amino linkage; X.sup.m− is an anionic species with a magnitude of charge m, where m is an integer of at least 1; and n is a number, provided that n×m=1. Also described herein are methods for removing one or more oxyanions from a liquid source by use of the above compound or mono-pyridyl derivative thereof.

The invention relates to a method for the fractioned separation of valuable substances from aqueous many-component mixtures such as aqueous wastes, sludges and sewage sludge under supercritical conditions. The invention also comprises valuable substance fractions that are enriched after the method according to the invention, more particularly phosphorous-containing and phosphorous- and ammonium-containing compounds such as fertilisers and synthesis gas as an energy source and as a valuable substance for the chemicals industry. The invention comprises devices for carrying out the methods. With the method and devices according to the invention, valuable substances can be completely recovered from wastes, sludges and sewage sludge and given a new use. The methods and devices are particularly suitable for recovering phosphorous and ammonium in the form of plant-available fertiliser, for recovering metals and heavy metals, for producing synthesis gas and for obtaining hydrogen from synthesis gas, i.e. for mobility.

A method and a system for recovering nitrogen, and optionally phosphorus and/or potassium, from a liquid waste stream, such as a stream of urine or manure, or human urine is described. The method comprises passing the waste stream through a multi-compartment electrodialysis bipolar membrane (EDBM) system.

Provided is a purification material capable of highly efficiently removing contaminant components from water. A water purification material has a composition represented by a mixing ratio of zeolite, ferric hydroxide, activated carbon, titanium oxide, and magnesium hydroxide of 6 to 7:1 to 2:0.5 to 1:0.01 to 0.05:0.01 to 0.10 in terms of weight ratio.

A method of water treatment includes providing water that includes at least one contaminant. An effective amount of at least one filter media is added to the to the water that includes at least one contaminant. The water and the at least one filter media are agitated to form a homogeneous mixture. A cationic biopolymer is added to the homogeneous mixture of water and the at least one filter media. The water is separated from the at least one contaminant and the at least one filter media.

The present disclosure relates to methods of treating water to remove contaminants, including harmful metal ions, and water treatment plants for practicing such methods. In an embodiment, the process includes adding a sulfur-containing, metal-decreasing agent; an iron (III)-containing, metalloid-decreasing agent; forming a solid precipitate from the contaminated water, wherein the solid precipitate includes a solid metal sulfide, a solid iron metalloid, a solid calcium metalloid, or a combination thereof; and separating the contaminated water from the solid precipitate to form purified water.

The present invention relates to a process for forming or obtaining vivianite in or from a phosphorus-containing waterbody, sediment and/or sludge, to an apparatus for obtaining vivianite from a phosphorus-containing waterbody, sediment and/or sludge, and to the use of a composition comprising at least one alkaline earth metal peroxide and a magnetic separating apparatus for obtaining vivianite from a phosphorus-containing waterbody, sediment and/or sludge.

Provided is a purifying material capable of highly efficiently removing contaminant components from wastewater. A water purifying material having a composition of 30 to 40% total iron, 1 to 5% titanium, 0.1 to 1% magnesium, and 0.1 to 0.8% silica (silicon), and a method for manufacturing the water purifying material including: adding caustic soda to a solution containing 200 to 100 mg/L of bivalent iron, 20 to 100 mg/L of titanium ions, 5 to 50 mg/L of magnesium, and 3 to 30 mg/L of silica under conditions of 30 to 50° C. and pH 6.8 to 7.2 to carry out neutralization and reaction; separating and collecting an obtained solid at 100° C. or less; and drying the collected solid.

Systems and methods for intensive recirculating aquaculture are provided herein. An example system includes water sourced from a first segment of a saline aquifer, a recirculating aquaculture system receiving the sourced water and producing discharge water, and a water discharge point located within a second segment of the saline aquifer disposed below the first segment of the saline aquifer.

A method and system for reducing the concentration of nitrogen-bound nitrate from at least one of groundwater, surface water, or waste water is disclosed. The system includes an algal photobioreactor system. The photobioreactor includes a transparent tubular structure, a medium disposed inside the transparent tubular structure, and alga configured to adhere to the medium. The photobioreactor further includes a pump, and a light source. The method includes providing contaminant-containing water, adding the water to the algal photobioreactor system, adjusting at least one of temperature, ion concentration, CO.sub.2 concentration, pH, light wavelength, ion concentration or light intensity in the algal photobioreactor system to enhance growth of algae, removing water from the algal photobioreactor system, and harvesting the algal biomass. A system and method are also disclosed for reducing the concentration of organophosphates from water via an organophosphate-removing alga.