Industrial wastewater treatment is an excellent topic of the global environmental debate; thus, industrial wastewater is one of the largest sources of aquatic pollution, endangering the surrounding environment and being a health risk to living organisms.
Seeing industrial wastewater as a resource over waste will have a substantial positive impact on the scarce water resources and have a positive effect on the environment by avoiding untreated water discharges to water bodies. Industrial wastewater treatment is a complicated matter so let us touch on the questions there are about industrial wastewater treatment:
Industrial wastewater treatment is defined as the process used for treating wastewater produced by almost any industry as a by-product. Industrial wastewater treatment covers the mechanisms and processes used to treat wastewater that has been contaminated in some way by industrial or chemical activities.
The industry treats the water with the purpose of either discharging the water to a sanitary sewer or directly to the environment or to the purpose of reusing/recycling the water, as it can be a great resource. This process is known as pretreatment because the industry conducts the treatment before discharge to a public sewer system, in which it will be treated further.
More global and local regulations and standards appear, which the industry must comply with. Get an overview of industrial wastewater limits and requirements. The solution to that is industrial wastewater treatment.
Any industrial wastewater treatment process usually starts with an evaluation of the water and an assessment of the circumstances to define which treatment and specifications is necessary. Subsequently, the chemical and filtration processes are very different.
The most implemented chemical treatment processes are chemical precipitation, neutralization, adsorption, disinfection, and ion exchange. Common to these chemical water treatment processes is that you affect the substance by changing extraneous factors, for example, in the shape of injecting chemicals or changing temperatures. Subsequently, the processes differ.
In the process of chemical precipitation, dissolved inorganic is removed by adding an acid or alkali. It is done by changing the temperature or by precipitation as a solid. The precipitate can be removed by sedimentation, floatation, or other solid removal processes.
Neutralization is controlling the pH of the wastewater, whether it is acidic or alkaline, to keep the pH around 7. The lack of sufficient alkalinity will require the addition of a base to adjust the pH to the acceptable range. The lack of sufficient acidity will require the addition of an acid to adjust the pH to the acceptable range.
Adsorption is another chemical industrial wastewater treatment method. It is a physical process where soluble molecules (adsorbate) are removed by attachment to the surface of a solid substrate (adsorbent). Adsorbents must have an extremely high specific surface area. The surface of the adsorbent should be free of the adsorbate. Therefore, the adsorbent should be activated before use. A wide range of organic materials can be removed by adsorption, including detergent and toxic compounds.
Disinfection is a chemical treatment process conducted by treating the effluent with the selected disinfection to examine or at least inactivate the pathogens, such as microbes, viruses, and protozoan. The purpose of disinfection is the protection of microbial wastewater quality.
Ion exchange is a reversible reaction in which a charged ion in a solution is exchanged with a similarly charged ion, which is electrostatically attached to an immobile solid particle. The most common implementation of the ion exchange method in wastewater treatment is for softening, where polyvalent cations are exchanged with sodium. Practically, wastewater is introduced into a bed of resin. The bed is shut down when it becomes saturated with the exchanged ions, where it should be regenerated by passing a concentrated solution of sodium back through the bed.
Mechanical filtration can be done with, for example, sand filters. The sand filter technology was developed almost 200 years ago. Generally, sand filters are operated with downward-flowing fluids, and they are either driven by pressure or gravity. Shortly, a sand filter is a large tank with a thick bed of special grade sand. The dirty water is pumped into the sand filter and is led down through the sand by pressure or gravity. The sand particles retain debris, dirt, and medium-sized particles down to 10-50 microns. Sand filters may often depend on chemicals to provide adequate disinfection to remove bacteria and various pathogenic organisms.
Another mechanical filtration method is ceramic membranes. In the process of ceramic membrane filtration, the feed water enters the ceramic membranes, which are placed in housings to filter the industrial wastewater. A feed pump triggers the filtration process by generating pressure, which will make the feedwater move through the membranes. The permeate will start to move through the membrane structure as a filtered liquid which removes dirt, debris, heavy metals, oils, and particles down to 60 nanometers. The permeate will end up in a permeate tank ready to reuse or discharge. The concentrate, which is the concentrated feedwater, is sent to subsequent processing en route to filtration. In some industries, the concentrate is possible to reuse as well as the permeate. Dive further into the membrane filtration principles.
Primary wastewater treatment is a process of removing solid matter from industrial wastewater. This process involves the sedimentation of solid waste within the water, meaning that the solids in the water either float to the top or settle on the bottom. This is done after filtering out larger contaminants within the water. The wastewater passes through several tanks and filters that separate water from contaminants. The remaining sludge is then fed into a digester for further processing. The primary wastewater treatment process generally utilizes mechanical equipment to break up larger particles.
Secondary wastewater treatment is performed to remove the soluble organic matter and more of the suspended solids that escape the primary treatment. This process utilizes naturally occurring biological processes, for example, the use of anaerobic microorganisms, which are often used. The secondary treatment of wastewater makes use of oxidation to further purify wastewater. This can be done one of three ways:
Biofiltration employs sand filters, contact filters, trickling filters, or ceramic membranes to ensure that additional sediments are removed from the industrial wastewater.
Aeration is another secondary treatment method. This process entails mixing wastewater with a solution of microorganisms.
Oxidation pond utilizes natural bodies of water like lagoons. Wastewater is allowed to pass through this body for a period and is retained for two to three weeks.
When intended receiving water is very vulnerable to it effects of pollution, secondary effluent may be treated further by tertiary processes, which can be:
This wastewater management is mostly used for removing phosphates and nitrates from the wastewater.
With efficient and correct industrial wastewater treatment, water can be cleaned to such an extent that it can be reused. With ceramic membrane filtration, you can filter particles, suspended solids, and bacteria down to 3 microns, meaning that this water can be used for other purposes in the production depending on the type of production and processes.
Furthermore, you can significantly reduce your costs due to lowered water consumption by reusing the wastewater after filtration. You can lower your water processing costs by cleaning the wastewater and reusing it instead of discharging it and paying discharge fees. Simultaneously, you reduce your dependency on freshwater supplies due to your self-sufficient water supply.
Ceramic membrane technology can be up to 100 times more efficient than conventional industrial wastewater treatment technologies
