How Is Industrial Wastewater Treated?
Water is used throughout industrial processes to create products, perform chemical or physical reactions and to transport materials. However, it also picks up a range of contaminants along the way, which can result in wastewater being produced as an unwanted by-product of these processes.
Wastewater treatment involves a series of steps designed to remove all contaminants before it can be reused or discharged into a sewer network. Depending on what needs to be removed, there are many different processes that can be applied to industrial wastewater.
Industrial wastewater is produced in a variety of industries. It is often used for cleaning and rinsing industrial equipment, boiler feed, water cooling and heating, firefighting, and a variety of other purposes. Before this wastewater can be released into a body of water, it has to undergo treatment.
This treatment process varies by industry and involves a variety of methods to remove pollutants from the wastewater. It usually includes removing dissolved solids and solid mineral deposits, separating out oils or gases that have become suspended in the water, filtering out organic materials and remaining toxic substances, and neutralizing acidic or alkaline elements.
The filtration process typically involves a membrane that separates the suspended solid matter from the liquid. This separation is facilitated by pores that allow the fluid phase to pass through them, while retaining oversize particles. This can be done using gravity filtration or by vacuum.
A biological treatment process is one of the most common and effective methods for treating industrial wastewater. This type of treatment enables wastewater to be discharged to the environment without harming human health or contaminating drinking water sources.
In a biological treatment process, microorganisms break down soluble, colloidal and suspended organic substances in wastewater to stable end products. This is done through the biochemical decomposition of wastewaters, which may involve aerobic or anaerobic processes.
An anaerobic treatment, for example, uses bacteria to help organic material deteriorate in an oxygen-free environment. This is often the most effective way to remove nitrates, nitrites, selenates and sulfates from waste waters.
Several types of biological treatment technologies are available, including activated sludge and moving bed biofilm reactor (MBBR). MBBR systems provide the same treatment capacity as activated sludge in a smaller footprint, while also meeting strict environmental discharge quality standards.
Chemical treatment can be used to degrade a range of industrial wastewater contaminants that are difficult for biological treatments to treat. In addition to reducing the concentration of toxic cyanide and phenol, this process can also help remove heavy metals that have dissolved in the water.
The first step in the chemical process is to adjust the pH of the waste stream. This can be accomplished through the use of a variety of chemicals that can adjust the acidity or alkalinity of the wastewater.
Next, coagulant chemicals are added to the wastewater to begin coagulating solids in the wastewater. These chemicals are chosen based on the chemical makeup of the wastewater.
Coagulant chemicals reduce the negative electric charge of fine solid particles that are dispersed throughout the wastewater. They then cause these particles to aggregate into larger groups of particles that can be removed in a sedimentation process.
Evaporation is a way to treat industrial wastewater. It removes contaminants and concentrates liquid waste, such as salts and heavy metals.
The water vaporization process uses heat energy to break the bonds between the molecules in the liquid. This is a common process in the world of science and industry.
In some applications, evaporation can be used to recover valuable materials or to separate hazardous substances from a solution. It can also be used to concentrate liquid wastes for further treatment and disposal.
For example, metal finishing processes often use chelating agents such as EDTA or ammonia to prevent the normal precipitation of certain metal hydroxides. These reagents are difficult to remove from waste streams using conventional physicochemical methods.
Vacuum evaporators can be used to treat these waste streams without the need for additional chemicals. Consequently, they can minimize the production of regulated waste residues and increase the potential for recovery of valuable metals.