Wastewater treatment plant process. Wastewater treatment, reuse and disposal is a pressing environmental, economic and technological problem for many industrial facilities. The current methods often do not provide complete water purification and do not meet modern environmental standards. Formaldehyde paint shops wastewater (FSV) forms a waste of phenol, urea or melamine with formaldehyde.
Phenol resins are polycondensation products of phenol with formaldehyde.
Urea-formaldehyde resins modified with butyl alcohol are used for urea-alkyd paint production. Melamine-formaldehyde resins modified with alcohols are the basis of a melamine-alkyd paints.
Wastewater of paint formaldehyde productions is a complex multicomponent formation contaminated with organic and inorganic substances in dissolved, colloidal and coarse-grained dispersion states and may contain formaldehyde mass concentration of 50-3000 mg / dm3.
The maximum allowed concentration (MAC) of formaldehyde in fishery waters is 0.25 mg / dm3, so prior to discharge into sewer drains the wastewater must be thoroughly cleaned.
Wastewater treatment plant process. Deep wastewater purification removing formaldehyde is performed by biochemical oxidation. This process is based on adding strong oxidants into the system (hydrogen peroxide, potassium permanganate, etc.), and oxidation at high temperature and pressure (with significant operating costs), it also requires the construction of large and expensive structures, which return their costs only after processing significant amounts of wastewater.
The application of reagent methods has disadvantages, such as high costs of transportation, storage and dispensing of reagents, not to mention the usual high cost of the process.
Traditionally the methods of wastewater treatment are: biological, chemical and physico-chemical. The biological treatment is used for wastewater with concentrations of formaldehyde of 800-1500 mg / dm3, and can not be applied with high concentrations of formaldehyde, which is toxic to the processing microorganisms and requires the construction of large size and expensive structures.
Among the physicochemical and chemical methods, thermal (incineration), oxidation and absorption methods, and methods of condensation of formaldehyde with an alkaline reagent are the most commonly used. Non-catalytic incineration is applicable only in case of highly concentrated wastewater (15% formaldehyde). Using environmentally hazardous oxidants in oxidizing methods raises the question of separation of the remaining hazardous reagents from the wastewater. The use of many oxidants is also limited by their high cost and the possibility of secondary toxic reaction products.
Absorption methods are free from the above mentioned limitations, but are effective only in a narrow concentration range (300-400 mg / dm3 formaldehyde) and require the disposal of adsorbent or its regeneration.
Improving the efficiency of wastewater treatment plant process in paint production
The electromagnetic nano-mill (AVS) is an inductor with a hollow active chamber containing ferromagnetic particles. When power is applied, the ferromagnetic particles begin to rotate in the electromagnetic field.
These devices were designed in the 1960s-1970s and have been successfully used as intensifiers of different technological processes. Another application of the AVS is the wastewater treatment processes. The rapid physico-chemical wastewater treatment is achieved through intensive mixing, dispersing, acoustic and electromagnetic treatment, electrolysis and other factors. The same processes that last minutes and hours in the stirring devices, occur within seconds or tens of seconds in the AVS.
Moreover, the introduction of AVS units into the wastewater processing lines of various designs reduces the use of reagents, and also reduces the production floor space and optimizes energy consumption.