1. Physical Wastewater Treatment Methods
2. Chemical Wastewater Treatment Methods
2.1 Neutralization
The purpose of neutralization is to adjust the pH value to meet the requirements of the different processing units in the wastewater treatment system.
Neutralization may be used in order to treat acid wastewaters containing metals, the method comprising increasing the pH of the acid waste by addition of an alkaline reagent, to form a precipitate and collecting the precipitate. This way the incoming solution is pH adjusted to the optimum range for precipitating metals as hydroxides.
This step is conducted before the main step of wastewater treatment, that is clarification (=decantation), to fulfill the overall wastewater treatment objectives.
2.2 Flocculants & Coagulants
Flocculation and coagulation treatment chemicals are used in effluent water treatment processes for solids removal, water clarification, lime softening, sludge thickening, and solids dewatering.
Coagulants neutralize the negative electrical charge on particles, which destabilizes the forces keeping colloids apart. Water treatment coagulants are comprised of positively charged molecules that, when added to the water and mixed, accomplish this charge neutralization. Inorganic coagulants, organic coagulants or a combination of both are typically used to treat water for suspended solids removal.
Flocculants gather the destabilized particles together and cause them to agglomerate and drop out of solution. Examples of ChemTreat flocculants include low, medium, and high molecular weight polymers.
2.3 Oxidation
Oxidation reduces the biochemical oxygen demand of wastewater, and may reduce the toxicity of some impurities. Secondary treatment converts some impurities to carbon dioxide, water, and biosolids. Chemical oxidation is widely used for disinfection.
2.4 Ion Exchange
When water is too hard, it is difficult to use to clean and often leaves a grey residue. (This is why clothing washed in hard water often retains a dingy tint.) An ion exchange process, similar to the reverse osmosis process, can be used to soften the water. Calcium and magnesium are common ions that lead to water hardness. To soften the water, positively charged sodium ions are introduced in the form of dissolved sodium chloride salt, or brine. Hard calcium and magnesium ions exchange places with sodium ions, and free sodium ions are simply released in the water. However, after softening a large amount of water, the softening solution may fill with excess calcium and magnesium ions, requiring the solution be recharged with sodium ions.
2.5 Ozonation
Ozone (O3) is applied for the disinfection of drinking water, for the removal of effluents from wastewater treatment plants in a process called ozonation (or ozonisation) as well as for the degradation of organic and inorganic pollutants in wastewater.
2.6 Disinfection
The purpose of disinfection in the treatment of wastewater is to substantially reduce the number of microorganisms in the water to be discharged back into the environment for the later use of drinking, bathing, irrigation, etc. The effectiveness of disinfection depends on the quality of the water being treated (e.g., cloudiness, pH, etc.), the type of disinfection being used, the disinfectant dosage (concentration and time), and other environmental variables.
If your business is interested in solution to inlet water treatment, or has a demand for ion exchange materials, please contact NGO via phone number (024) 3566 8225 or email office@8ngo.com for direct consultation.
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