Wastewater components

Treatment technologies used in the porcelain enameling industry are generally chosen to remove the major wastewater components, such as suspended solids and toxic metals. Table 8.15 presents a summary of the treatment and disposal techniques used by this industry. Usually more than one treatment methods will be used at each facility.3 610... 

The sewer is dominated by heterotrophic microorganisms that degrade and transform wastewater components. These processes proceed under redox conditions determined by the availability of the electron acceptor. The importance of the processes for the sewer and the surroundings is not just caused by the removal and transformation of organic substrates — the electron donor—but is also a result of transformation of the electron acceptors exemplified by the formation of hydrogen sulfide from sulfate. 

When wastewater components are applied as model parameters for simulation of the transformations taking place in a sewer, the fundamental requirements depend on model objectives. A basic requirement (following the concept depicted in Figure 2.2) is that the following two types of components be included when focusing on the heterotrophic microbial transformations ... 

Reaeration in sewer networks the presence of dissolved oxygen in wastewater of sewer systems determines if, and to what extent, aerobic and anaerobic processes proceed. The air-water oxygen transfer (the reaeration) determines the potential of aerobic transformation and corresponding removal of wastewater components in many sewer... 

Almeida (1999) made transformation studies of wastewater components in a gravity sewer. The sewer has a length of 7.2 km and a typical retention time of 1.5 hours. An average slope equal to 0.007 and several drops resulted in a sewer dominated by aerobic processes. In addition to the organic components (CODtot, CODsol and BOD), other relevant parameters (ammonia, nitrate, TSS... 

TABLE 5.1. Estimated Average Removal Percentages of Selected Wastewater Components in a 7.2-km Gravity Sewer with an Average Retention Time of about 1.5 h. The Sewer Processes are Predominantly Aerobic (Almeida, 1999). 

Chlorine the use of chlorine (Cl2) as a sulfide-controlling agent is based on its poisoning effect on the biological system and its oxidizing effect on sulfide. Chlorine is nonspecific, and a great number of side reactions with wastewater components may occur. Even concentrations of about 50 g m-3 have not efficiently been able to reduce sulfide concentrations of about 5-10 gS m-3. Chlorine is an environmentally problematic chemical that generally cannot be recommended for use in sewer systems. 

Tanaka, N., T. Hvitved-Jacobsen, and T. Horie (2000a), Transformations of carbon and sulfur wastewater components under aerobic-anaerobic transient conditions in sewer systems, Water Env. Res., 72(6), 651-664. 

The procedures described in Sections 7.2.1 to 7.2.4 refer to the aerobic formulated sewer process model (cf. Table 5.3) whereas Section 7.2.5 deals with methods applied for determination of model parameters to include transformations of wastewater components under anaerobic conditions (cf. Table 6.6). 

FIGURE 7.7. Overview of procedures 1 to 4 for determination of wastewater components and parameters for the sewer process model. 

Spanggord RJ, Mortelmans KE, Griffin AF, et al. 1982b. Mutagenicity in Salmonella typhimurium and structure-activity relationships of wastewater components emanating from the manufacture of trinitrotoluene. Environ Mutagen 4 163-179. 

Sundvall A, Marklund H, Rannug U. 1984. The mutagenicity on Salmonella typhimurium of nitrobenzoic acids and other wastewater components generated in the production of nitrobenzoic acids and nitrotoluenes. Mutat Res 137 71-78. 

Chou, W.L., Speece, R.E., Siddiqi, R.H. (1979) Acclimation and degradation of petrochemical wastewater components by methane... 

The theoretical chemical (or ultimate) oxygen demand, or ThCOD (BODU), can be calculated for a wastewater with relatively few oxidizable components. The procedure requires one to calculate the equivalent oxygen concentration necessary for the complete stoichiometric oxidation of each of the wastewater components to its corresponding highest oxidation state and sum them for the total wastewater ThCOD. Carbonaceous components of wastewater generally considered to be fully... 

Shackelford WM, Cline DM, Faas L, et al. 1983. An evaluation of automated spectrum matching for survey identification of wastewater components by gas chromatography-mass spectrometry. Anal Chim Acta 146 15-27. 

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