Wastewater biological methods

Various physical, chemical, and biological methods have been used for the treatment of dye-containing wastewater. However, these conventional technologies have disadvantages like poor removal efficiency and high running cost. Therefore, low-cost sorbents which can bind dye molecules and be easily regenerated have been extensively searched and tested [3-7]. 

Treatment of dye-contaminated wastewater discharged from the textile and other dye-stuff industries is necessary to prevent contamination of soil and surface and ground water. Currently, there are several physicochemical and biological methods... 

Treatment of dye wastewater involves physical, physico-chemical, chemical, and biological methods. Physical processes are dilution, filtration, and gamma radiation. Physico-chemical includes adsorption, coagulation, flocculation, precipitation, reverse osmosis, ion exchange, etc. 

The effectiveness of a combined reduction-biological treatment system for the decolorization of nonbiodegradable textile dyeing wastewater has been investigated. The bench-scale experimental comparison of this technique with other reported combined chemical-biological methods showed higher efficiency and lower cost for the new technique [35]. 

Zyllaa R, Sojka-Ledakowicza J, Stelmachb E et al (2006) Coupling of membrane filtration with biological methods for textile wastewater treatment. Desalination 198 316-325... 

Generally, wastewater treatment methods can be broadly classified into biological, physical (i.e. mechanical) and chemical [3, 12-14]. Biological... 

One difference between these systems and the biological treatment of nonhazardous wastewater is that the exhaust air may contain volatile hazardous substances or intermediate biodegradation products. Therefore, the air must be treated as secondary hazardous wastes by physical, chemical, physico-chemical, or biological methods. Other secondary hazardous wastes may include the biomass of microorganisms that may accumulate volatile hazardous substances or intermediate products of their biodegradation. This hazardous liquid or semisolid waste must be properly treated, incinerated, or disposed. 

Hamza, A. Evaluation of treatability of the pharmaceutical wastewater by biological methods. In Current Practices in Environmental Engineering Hamaza, A., Ed. International Book Traders, Delhi, India. 1984 37-44. 

A large number of techniques have been described in the literature, for example, dyestulf adsorption, oxidative and reductive treatments, electrochemical oxidation or reduction methods, electrochemical treatment with flocculation, membrane separation processes, and biological methods [37-55]. Each of these techniques offers special advantages, but they can also be understood as a source of coupled problems, for example, consumption of chemicals, increased COD, AOX, increased chemical load in the wastewater, and formation of sludge that has to be disposed. 

Mantis, I., D. Voutsa, and C. Samara. 2005. Assessment of the environmental hazard from municipal and industrial wastewater treatment sludge by employing chemical and biological methods. Ecotoxicol. Environ. Saf. 62 397 407. 

The use of catalysts, furthermore, is required in the processes of wastewater purification by reducing treatments. Catalysts also find also application as complementary technologies to other wastewater treatment methods, such as in the control of odour, VOC, N2O and NOx emissions from wet oxidation treatments (for example, in the wet oxidation of industrial sludges), and of odours and VOC emitted from biological processes (aerobic and anaerobic). Although usually commercial catalysts are used in these cases, there are often unpredicted effects in treating complex mixtures and thus more specific catalysts would be preferable. The same is valid for catalysts used to convert stripped VOC from contaminated groundwater. 

Among these plants, the wastewater rehabilitation plant of the Voronezh synthetic rubber plant (Russia) is worth to mention [2]. Here, two electron accelerators (0.7-1 MeV energy and 50 kW power), can treat up to 2,000 m of wastewater per day with the specific goal to transform the non-biodegradable emulsifier Nekal into a biodegradable form. A further decomposition is achieved with biological methods. 

Wastewaters contaming aromatic organic compounds must be pre-treated be re they are discharged into conventional waste treatment systems. A variety of these compounds are reftactory, toxic and. inhibitory in nature. The purpose of the pretreatment is to remove or reduce these compounds to less toxic or more biodegradable mtermediate products which can be treated by conventional biological methods (6). Examples of organic compounds that are toxic in nature are resorcmol, vanillin and salicylic acid. 

D, trifluralin, and other herbicides by photooxidation (Kearney et al. 1987). The process may be used as a waste disposal pretreatment. Herbicides may be removed from wastewaters by pretreatment with oxidizing agents, activated carbon, and biological methods. 

SBR is a biological method, which is an activated sludge wastewater treatment technology under intermittent aeration. Different from the traditional wastewater treatment process, the operation mode of space partitioning was placed by time division technology, steady-state biochemical reactions was placed by non-stable alternative technology the traditional dynamic precipitation... 

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