In the early days of variable frequency drive (VFD) technology, the typical application was in process control for manufacturing synthetic fiber, steel bars, and aluminum foil.
Some wastewater applications require chlorine residuals greater than can be effectively monitored using DPD due to the oxidation of the Wurster dye to a colorless Imine. Such applications include industrial wastewater processes that inherently have a high chlorine demand thereby requiring a more robust monitoring method.
Before water can be used as a safe and reliable source for drinking water, it must be properly treated. Since water is a universal solvent, it comes in contact with several different pathogens, some of which are potentially lethal, and inactivation is accomplished through chemical disinfection and mechanical filtration treatment. This treatment consists of coarse filtration to remove large objects and pre-treatment which includes disinfection using chlorine or ozone
Organic carbon compounds vary greatly. In fact, one of the first lessons in most introductory Organic Chemistry courses explains that the number of possible carbon compounds is virtually infinite due to carbon’s ability to form long, chain-like molecules. While chromatographic methods like gas chromatography (GC) or high-performance liquid chromatography (HPLC) are able to make quantitative determinations for specific compounds, the user must first know which specific compounds to look for.
Electrodeionization (EDI) is a widely used water treatment process. EDI technology is an electrochemical process that uses ion selective membranes and an electrical current to continuously remove ions from water. The process uses ion exchange resin to remove the ions from the feed stream, producing pure water.
Water in petrochemical feedstocks can cause problems for processors. Freezing of pipe lines and valves and poisoning of expensive catalysts are just a few examples.
Pesticide residue laboratories are required to undertake analyses of an ever increasing number of samples. The analyses typically involve use of multi-residue methods (both GC-MS and LC-MS) to test for over 500 pesticide residues.
In 2013 the Drinking Water Inspectorate for England & Wales announced that water samples collected in England and Wales must be tested in a laboratory that meets specific standards for drinking water sampling and analysis. At the time of the new instruction, the chlorine method employed at the Welsh Water Bretton laboratory was unable to meet these requirements, notably for the prescribed limit of detection. This prompted the laboratory to investigate new analytical options for monitoring residual chlorine.
In a number of water, wastewater and industrial process applications, pH is one of the most critical and highly sensitive analytical measurements. Examples of critical pH applications include: Reverse Osmosis (RO) systems in which a controlled feed of caustic solution is typically added to the feed stream in order to convert a portion of dissolved carbon dioxide into bicarbonate precipitate allowing for removal by the RO membrane. By Rafik H. Bishara, Steve Jacobs, and Dan Bell
In order to reduce the formation of harmful disinfection byproducts in drinking water, alternative disinfectant use has become increasingly widespread. Monochloramine is a leading alternative disinfectant that offers advantages for municipal water. This tech brief details the removal of monochloramine using activated carbon.
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