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• • Part of the book series (HEE, volume 4) Abstract Water aeration has been long used in water treatment for the removal of odor and taste-causing compounds, the oxidation of iron and manganese, as well as corrosion control and aesthetics. Since the mid-1970s, however, the process has been used to remove carcinogenic and hazardous chemicals from water. These chemicals include volatile organics such as trihalomethanes, radon, trichloroethylene, tetrachloroethylene, 1,1,1-trichloroethane, chloroform, and toluene. As a result, water aeration may be the single most important water treatment process used in the 21st century.

Wastewater systems have long been subject odor and corrosion. The wastewater odor is the driving force behind implementing controls for these systems.

Corrosion, however, has the greatest potential for environmental, systemic and economic harm. This damage can be in the form of burst pipes and other equipment failures. Failures of this type require equipment repair and replacement, and they have the potential to expose the environment to releases of hazardous waste that may be difficult, if not impossible, to contain or recover. Corrosion caused by H 2S A major contributor to odor and corrosion in industrial systems is hydrogen sulfide (H 2S) and its associated compounds.

Free Download Winzip For Blackberry 9800 more. Evaluation of sanitary sewer sulphide, odor and corrosion potential. Design manual: Sulphide and corrosion prediction control. Design Manual: Odor and corrosion control in sanitary sewerage systems and treatment plants. Cincinnati: EPA. Process design manual for sulphide control in sanitary. View Robert Bowker’s profile. Odor and Corrosion Control in Sanitary Sewers. This EPA Design Manual is still widely used as a reference for evaluating and.

Some industrial wastewater contains sulfur compounds, which provide the molecular basis for the generation of H 2S. H 2S arises from the combination of anaerobic conditions and the presence of sulfites and sulfates with the slime layer – colonies of microorganisms present on the inner walls of all collection systems. Sulfate reducing bacteria (SRB) will use these compounds in the absence of free oxygen (O 2) for metabolism. They do not use the sulfur component, and it is available to react with water, specifically free protons (H +), resulting in the generation of H 2S. Following its generation, H 2S can be released into the atmosphere and find its way to receptors through junctions of the atmosphere and collection system, at which point it is an odor concern. H 2S is a colorless gas that has a characteristic rotten egg odor, is highly toxic and is corrosive to certain metals. It is heavier than air, meaning it can accumulate in wells, manholes and other similar locations with little ventilation.

Its effects on humans, at varying concentrations relative to ambient air, are shown in Table 1. Sulfuric acid is also a byproduct of anaerobic SRB – one of the primary causes of corrosion in collections systems. H2S health effects at different concentrations H 2S becomes a corrosion issue when it contacts moist concrete or steel, among other metals, in the presence of oxygen, even at very low gaseous concentrations. Conditions such as these are common in the headspace of some pipes and other areas where the collection system has easy access to atmospheric oxygen. SRB in these areas convert the H 2S into sulfuric acid, which then begins a destructive reaction with the infrastructure. Historically, control of odor and corrosion has been implemented through either vapor phase techniques, where the headspace of a system is treated, or liquid phase techniques, where treatments target the liquid flow.

Vapor phase treatments like scrubbers do not provide corrosion control. Some of the liquid phase techniques offer corrosion control. The most common method of inducing liquid phase treatment, or directly treating the wastewater inside the collection system, has been by dosing chemicals into the system. A constant and continuous dose of chemical is fed from a large reservoir with a small pump into the collection system, typically at a manhole or pump station. These chemicals are meant to react with the odor-causing compounds present in the wastewater or cease their formation and/or release from solution.