Cyanides are used in a number of chemical synthesis and metallurgical processes (as simple salts or cyanide complexes). As a class, cyanides are highly toxic and must be destroyed or removed from wastewaters prior to discharge. The most common method for treating free or simple cyanide is alkaline chlorination. However, chlorination of cyanide results in highly toxic intermediates (e.g., cyanogen chloride) and, if organic material is present, chlorinated VOC’s. These compounds, together with the residual chlorine,...
Deposits in water systems, especially in heat exchangers, result in a significant heat transfer reduction, in low efficiency and a loss of cooling capacity. Some systems, after long operational periods without any water conditioning or with inadequate treatment, need cleaning. Therefore Kurita Water Solutions proposes acidic, alkaline and neutral cleaners to remove deposits, scale, fouling, dirt, grime or impurities.
Oxidation Reduction Potential or Redox is the activity or strength of oxidizers and reducers in relation to their concentration. Oxidizers accept electrons, reducers lose electrons. Examples of oxidizers are: chlorine, hydrogen peroxide, bromine, ozone, and chlorine dioxide. Examples of reducers are sodium sulfite, sodium bisulfate and hydrogen sulfide. Like acidity and alkalinity, the increase of one is at the expense of the other.
Radium is found naturally in uranium ores. It is an alkaline earth metal that decomposes in water and it is over a million times more radioactive than the same mass of uranium. As a radiological hazard that emits alpha, beta, and gamma rays, it is a carcinogen.
Industrial water softening is a process that utilizes ion exchange resins to reduce the concentration of calcium and magnesium ions. These alkaline earth metals can cause scaling and insolubility problems in the everyday uses of water by forming calcium and magnesium carbonate scales.
Hydrogen Peroxide as a Replacement for Sodium Hypochlorite
Hydrogen peroxide may be used in both mist scrubbers and packed tower scrubbers as a replacement for sodium hypochlorite (bleach). Like bleach, the process involves two concurrent mechanisms: 1) absorption of the odors (H2S) into the alkaline scrubbing solution; and 2) oxidation of the absorbed sulfide in solution.
H2S + NaOH → NaSH + H2O
4H2O2 + H2S → H2SO4 + 4H2O
Typical dose ratios are 5 parts H2O2 per part H2S or, when...
Manufacturing, metal fabrication and metal finishing require multiple washing processes to remove residue, oil, acids and other lubricants and contaminants before during and following various process steps. This generates large volumes of wastewater containing alkaline, acid solutions, heavy metal wastewaters, paint, plating residue wastewater, and other metal fabrication wastewaters. Wastewater and wash water from spills and floor cleaning must also be properly disposed. These manufacturing waste waters cannot...