A method and system for treating cyanide-containing fluids, in particular cyanide-containing waste water, wherein cyanide-containing fluid is subject to a pretreatment in a pretreatment zone, in which at least one predetermined pH value and a predetermined temperature is set, wherein a base fluid is formed with the pretreatment. Base fluid is reacted at least with an oxidation means in at least one reaction reactor, whereby an oxidation reaction of the cyanide is initiated. Fluid from the reaction reactor is transferred as intermediate fluid into at least one process reactor, in which conditions exist in which the oxidation reaction of the cyanide initiated in the reaction reactor can take place, wherein a process fluid is formed. A continuous flow of fluid is maintained at least periodically, wherein the base fluid is transferred continuously from the pretreatment zone into the reaction reactor, intermediate fluid is transferred continuously from the reaction reactor into the process reactor, and process fluid is removed continuously from the process reactor.

Provided is a treatment method of waste water containing ferricyanide complex and oxalate, comprising under the condition of weak acidity to weak alkalinity, firstly adding an appropriate amount of divalent manganese ions to make the divalent manganese ions combined with ferrocyanide ions and part of oxalate ions in wastewater to form a mixed slag mainly composed of manganese ferrocyanide to achieve the purpose of removing most of the cyanide and a small amount of organic substance; adding excess divalent manganese ions to the first filtrate to make the divalent manganese ions fully combined with the oxalate in the wastewater to achieve the purpose of removing organic substance, and then adding an appropriate amount of alkali to the second filtrate to form precipitation to achieve the purpose of recovering manganese; then adding an appropriate amount of ferrous salt to achieve the purpose of removing the remaining cyanide and organic substance.

The invention provides a bound sulfided metal containing metals such as nickel, cobalt, iron manganese or zinc for removing selenocyanate from aqueous streams. The binder may be alumina, silica, clay or metal oxide. The amount of sulfur in the bound sulfided metal may range from 5-75% by weight. In one embodiment, the bound sulfided metal is formed and reduced and placed in a column system that comprises one or more columns and may comprise a Lead-Lag1-Lag2-Polisher series of columns.

Methods and systems for reducing the concentration of selenium species in water, particularly water containing recalcitrant selenium species. In the methods and systems, water containing one or more selenium species is treated with permanganate to provide permanganate-treated water, which is then contacted with a zero-valent iron treatment system comprising (a) a reactive solid comprising zero-valent iron and one or more iron oxide minerals in contact therewith and (b) ferrous iron.

Methods and systems for reducing the concentration of selenocyanate in water. In the methods and systems, water containing selenocyanate is treated an oxidant to provide oxidant-treated water, which is then contacted with a zero-valent iron treatment system comprising (a) a reactive solid comprising zero-valent iron and one or more iron oxide minerals in contact therewith and (b) ferrous iron.

A modified aqueous acid composition comprising: sulfuric acid; a compound comprising an amine moiety and a sulfonic acid moiety; and a peroxide; wherein sulfuric acid, said compound comprising an amine moiety and a sulfonic acid moiety and said peroxide are present in a molar ratio of no less than 1:1:1. Also disclosed are methods of using such compositions for the decomposition of toxic chemicals such as cyanides.

Provided is a wastewater treatment process using an electrochemical electrode device. The electrochemical electrode device comprises at least one electrochemical electrode (30) comprising an appropriate electrode plate. The process comprises the following steps: causing water containing an undesired solute to pass through at least one electrochemical electrode (30); applying a direct current to the electrochemical electrode (30) to destroy the undesired solute in the water so as to output water having a lower concentration of the undesired solute. The direct current is adjusted via a specific power control procedure. The control procedure at least comprises the following cycle of an applied current sequence: a period of operation with a preset constant current flowing through an electrochemical electrode (30); applying a reverse constant current to reverse positive and negative electrodes while maintaining an absolute magnitude of the constant current; and a period of operation with the constant current flowing through the electrochemical electrode (30).

A procedure and a system for the extraction of isocyanuric acid is disclosed. According to the invention, the water containing isocyanuric acid is passed through a bed with an adsorbent material, the bed regeneration is carried out by using a liquid regeneration medium, the liquid regeneration medium that contains isocyanuric acid in solution is collected, its recovery is carried out by adding a solid complexing substance, the suspension obtained is passed through a filtering medium and isocyanuric acid is recovered and the liquid extraction medium is regenerated. The system comprises an adsorption column, a deposit of regenerating substance, a filtering medium, a dosage tank to dose the regenerating substance, a compressor, a drive pump and a valves system to configure the equipment according to the phase of the cycle in which it has to operate.

There are provided systems (10) and processes for the selective removal of cyanide from a wastewater stream (12) comprising cyanide and an amount of organic compounds therein.

The invention relates to the proppants and proppant substrates treated with active compounds that reduce the presence of contaminants in fluids, methods of using those materials, as well as methods of making those materials. The invention further provides that the contaminated fluids are associated with wells, including oil and gas wells.