Industrial Wastewater Treatment Methods
There are a variety of industrial wastewater treatment methods that can be used depending on the type of industry and specific operational practices. It can vary from a simple septic tank or filtration system to a bioremediation plant.
Wastewater from different industries can contain a wide range of pollutants that need to be removed. This can include chemicals, heavy metals, organic compounds, and more.
1. Chemical Treatment
Industrial operations produce wastewater that must be treated before it is discharged into a sewer system. This wastewater can be comprised of both organic and inorganic matter in varying concentrations.
Chemical treatment is an important part of an industrial wastewater treatment process. This treatment uses specialized chemicals to expedite disinfection and other wastewater-related cleaning processes.
These include chemical coagulation, oxidation, and ion exchange methods. Some common water treatment chemicals include hydrochloric acid, sodium hypochlorite, and magnesium hydroxide.
2. Physical Treatment
Wastewaters have many contaminants which require treatment before they are discharged into the environment. The treatment process separates the pollutants from the water and leaves an effluent that is clean and safe.
Physical treatment, also called mechanical – physicochemical treatment, removes solids from wastewater by use of equipment such as racks, screens, comminutors, clarifiers (sedimentation and flotation), filtration and centrifugal separation.
Physical wastewater treatment is particularly important for removing large non-biodegradable and floating substances that frequently enter wastewater works, such as rags, papers, plastics, tins and containers. This prevents damaging effects on downstream plant and equipment. It also helps to reduce sewer surcharge fees.
3. Biological Treatment
Biological treatment is a form of wastewater treatment that uses naturally occurring organisms to decompose organic substances. The process is used to treat municipal and industrial wastewater.
Several types of biotreatment processes exist, including activated sludge, trickling filters, pond and lagoon-based treatments, oxidation ditches, and constructed wetlands.
Biological treatment systems use oxygen to help the microorganisms break down organic matter in wastewater. These processes can remove a variety of pollutants from wastes including nitrates, nitrites, selenates and selenites, and sulfates.
4. Microbiological Treatment
Biological treatment is a process that uses a variety of microorganisms to break down waste. These bacteria can either be autotrophic (they obtain their energy from the organic matter in the waste) or heterotrophic (they degrade the organic matter).
In a standard system, aerobic microbes are used to break down the wastewater by using free oxygen in the water. Anaerobic bacteria are also commonly used in new treatment plants, but they must be mechanically fed oxygen to be effective.
A key factor in the success of bacterial cultures is the quality of the water. ELGA offers a wide range of water purification systems to ensure that laboratories around the world can perform bacterial culture without worrying about impurities that could negatively affect results.
5. Electrochemical Treatment
In order to reduce the environmental impact of industrial wastewater treatment processes, electrochemical methods are increasingly being applied. They can also contribute to energy- and raw material-efficient water recycling.
The most established and studied electrochemical water treatment methods are electrooxidation (EO), electrocoagulation (EC), electroflotation (EF), and electrodialysis (ED).
Besides these well-developed techniques, emerging technologies such as electrodeionization, capacitive deionization, electro-Fenton, microbial fuel cell treatment, photo- and sonoelectrocatalyses can be used to increase further removal rates of pollutants, eliminate drawbacks, and extend the applicability of existing treatment processes.
Ultrafiltration is a process that removes small particles and chemicals, including rust and heavy metals. It is also used to purify water to ensure that it meets drinking water standards.
The process works by applying water to a porous membrane. The pressure difference allows water to pass through the pores, while all matter larger than the pore size is retained on the surface of the membrane.
This process is ideal for removing colloids, proteins, bacteria, pyrogens and macromolecules that are too large for microfiltration or nanofiltration. It can also be used to concentrate high molecular weight constituents, allowing for enhanced concentration of nutrients or other compounds.