Wastewater biological treatment aerobic

There are two methods of biological treatment aerobic and anaerobic (217). The aerobic systems use free oxygen dissolved in the wastewater to convert wastes in the presence of microorganisms to more microorganisms, energy required for their existence, and carbon dioxide. The anaerobic process occurs in the absence of free oxygen and converts the waste to methane and carbon dioxide, generally in deep tanks or basins, and can produce odor problems when sulfides or sulfates are present in the wastewater. 

A 3 Gaseous (gases, vapors, airborne particulates) W = Wastewater (aqueous waste) B11 Biological Treatment - Aerobic... 

In any case the wastewater will finally be fed into rivers, lakes, or the sea thus some wastewater treatments have to be performed before the textile effluents are released either to the communal wastewater treatment plant (CWWT) or into the rivers, lakes, and so on. Normally physical and (bio-) chemical treatments (e.g., adjustment of pH, temperature, sedimentation, flocculation) are performed in the textile plant, while the following biological treatment (aerobic, anaerobic degradation) is performed either in the textile plant or in a CWWT. The site of the biological treatment is dependent on the location of the textile plant however, a biological treatment of textile effluents preceding release into surface water is state of the art. 

Figure 4.12. Comparison between aerobic and anaerobic wastewater biological treatment, a wastewater, b biomass content, c hydraulic retention time.

The well-known aerobic downflow process is a trickled bed filter. Attached growth is used in the biological treatment of wastewater. Air passes through the bed while the liquid is forced to down by gravity. Figure 13.2 shows the liquid gas system for the mass transfer... 

Azo dye-containing wastewaters seems to be one of the most polluted wastewaters, which require efficient decolorization and subsequent aromatic amine metabolism. On the basis of the available literature, it can be concluded that anaerobic-aerobic SBR operations are quite convenient for the complete biodegradation of both azo dyes and their breakdown products. Nevertheless, like the other methods used for biological treatment, SBRs treating colored wastewaters have some limitations. Presence of forceful alternative electron acceptors such as nitrate and oxygen, availability of an electron donor, microorganisms, and cycle times of anaerobic and aerobic reaction phases can be evaluated as quite significant. 

For effective biological treatment of dye wastewater, immobilization of bacteria under aerobic anaerobic high-rate reactors should be given special attention. The main cause of effective treatment of these xenobiotics under immobilized condition in high rate reactors is the rapid facile reduction of these compounds to products of lower toxicity [68, 69]. Moreover, the immobilization of anaerobic bacteria and maintenance of a high concentration of biomass in the high rate reactors are factors that improve the tolerance of the anaerobic system to toxic substances [70, 71]. 

Isik M, Sponza DT (2006) Biological treatment of acid dyeing wastewater using a sequential anaerobic/aerobic reactor system. Enzyme Microb Technol 38 887-892... 

Biological treatment techniques anaerobic digestion processes, aerobic digestion processes, nitrification, denitrification, and central biological wastewater treatment. 

Aerobic biological treatment process for domestic or industrial wastewaters. Treated water from this process can often be used as a low cost makeup water source for cooling towers. 

Beltran-Heredia J, Torregrossa J, Garcia J, Dominguez JR, Tiemo JC. Degradation of olive mill wastewater by the combination of Fenton s reagent and ozonation processes with an aerobic biological treatment. Water Sci Technol 2001 44 103-108. 

The aerobic complete-mix biological treatment process without recycle, as shown in the drawing, receives wastewater with a biodegradable soluble COD (bsCOD) concentration of 500 g/m3. The flowrate is 1000 m3/d and the reactor effluent bsCOD and suspended volatile solids (VSS) concentrations are 10 and 200 g/m3, respectively. Based on these data ... 

---