Industrial wastewater treatment covers the mechanisms and processes used to treat wastewater that is produced as a by-product of industrial or commercial activities. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to surface water in the environment. Most industries produce some wastewater although recent trends in the developed world have been to minimize such production or recycle such wastewater within the production process. However, many industries remain dependent on processes that produce wastewaters. There are various treatment technologies for treating effluent of different types of industries. Some of them are:-
UASB
Upflow anaerobic sludge blanket (UASB) technology, normally referred to as the UASB reactor, is a form of an anaerobic digester that is used for wastewater treatment. The UASB reactor is a methanogenic (methane-producing) digester that evolved from the anaerobic clarigester. Similar but variant technology to UASB is the expanded granular sludge bed (EGSB) digester.UASB uses an anaerobic process whilst forming a blanket of granular sludge that suspends in the tank. Wastewater flows upwards through the blanket and is processed (degraded) by the anaerobic microorganisms. The upward flow combined with the settling action of gravity suspends the blanket with the aid of flocculants. The blanket begins to reach maturity at around three months. Small sludge granules begin to form whose surface area is covered in aggregations of bacteria. In the absence of any support matrix, the flow conditions create a selective environment in which only those microorganisms capable of attaching to each other survive and proliferate. Eventually, the aggregates form into dense compact biofilms referred to as “granules”.
Trickling Filter
A trickling filter consists of a bed of rocks, gravel, slag, peat moss, or plastic media over which wastewater flows downward and contacts a layer (or film) of microbial slime covering the bed media. Aerobic conditions are maintained by forced air flowing through the bed or by natural convection of air. The process involves adsorption of organic compounds in the wastewater by the microbial slime layer, diffusion of air into the slime layer to provide the oxygen required for the biochemical oxidation of the organic compounds. The end products include carbon dioxide gas, water, and other products of the oxidation. As the slime layer thickens, it becomes difficult for the air to penetrate the layer and an inner anaerobic layer is formed. The fundamental components of a complete trickling filter system are:
1. A bed of filter medium upon which a layer of microbial slime is promoted and developed.
2. An enclosure or a container that houses the bed of filter medium.
3. A system for distributing the flow of wastewater over the filter medium.
4. A system for removing and disposing of any sludge from the treated effluent.
The treatment of sewage or other wastewater with trickling filters is among the oldest and most well-characterized treatment technologies. A trickling filter is also often called a trickle filter, trickling biofilter, biofilter, biological filter or biological trickling filter.
Chemical Treatment
In Chemical treatment, Effluent is treated with chemical reaction, generally, Lime Alum and poly is used for chemical reactions. A chemical reaction involves two processes, coagulation, and flocculation. After that sludge is removed from the system and clear water is treated further.