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Wastewater quality

Wastewater quality eharaeteristies total suspended solids, organie loading, and so on. [Pg.489]

These examples show that when excluding substances like heavy metals and organic micropollutants, the wastewater quality is closely related to the microbial biodegradability of organic matter. This characteristic feature is not... [Pg.38]

Biomass and substrate must be separately described to establish a concept for classification of wastewater directed toward a description of the microbial processes. For several reasons, e.g., to allow widespread application and to observe a basic mass balance, the organic matter expressed in terms of COD is a central parameter for wastewater quality. According to the concepts used in the active sludge models, the classification of wastewater in a sewer network can also be subdivided as outlined in Figure 3.1 (Henze et al., 1987, 1995a, 2000). A direct interaction between sewer and treatment plant processes is therefore within reach. [Pg.39]

Hvitved-Jacobsen, T., J. Vollertsen, andN. Tanaka (1999), Wastewater quality changes during transport in sewers — An integrated aerobic and anaerobic model concept for carbon and sulfur microbial transformations, Water Sci. Tech., 39(2), 242-249. [Pg.63]

Both s0 and ydepend on the same basic characteristics as the KLa value, i.e., sewer structure characteristics, wastewater quality and temperature. Simple empirical equations expressed in terms of a major important parameter, the height, H, have been developed (Table 4.8). [Pg.90]

The expressions presented in Table 4.8 are compared in Figure 4.6. The constants included in the expressions are a result of the investigations performed by the authors mentioned in the table. These constants may vary according to a number of site-specific conditions including temperature and wastewater quality characteristics. [Pg.91]

It is important to notice that the empirical expressions (5.11) and (5.12) are simple, and, contrary to the DO mass balance in Equation (5.9) — as a part of the conceptual description of sewer processes — do not include a dynamic description of the wastewater quality changes taking place in a sewer. However, the simple DO mass balance expressed in Equation (5.10) may give useful information, as shown in Example 5.3. Generally, it is important that both simple and more complicated models exist. A model most appropriate to use will always depend on the actual objective and the information available. [Pg.117]

The processes in the DO mass balance, and thereby the DO concentration, are subject to great variability. Especially in sewers with low DO concentrations, this variability may ultimately result in varying aerobic/anaerobic conditions, a case that will be further dealt with in Chapter 6. At a specific location, the flow, the wastewater quality and the temperature vary over time, daily and annually, and result in substantial changes in the DO concentration. Example... [Pg.119]

Example 5.4 DO concentration profiles in a sewer pipe subject to daily variations in flow, wastewater quality and temperature (Gudjonsson etal., 2001)... [Pg.119]

Figure 5.12 illustrates that the flow conditions, y/D, and the quality of the wastewater affect the DO concentration. According to the daily variations in wastewater quality and the y/D ratio (0.14-0.18), the simulated DO concentration varies between 0.5 and 2.5 g02 m-3. This result fits well with the observations shown in Figure 5.10. [Pg.119]

Nielsen, P.H., K. Raunkjaer, and T. Hvitved-Jacobsen (1998), Sulfide production and wastewater quality in pressure mains, Water Sci. Tech., 37(1), 97-104. [Pg.126]

The sulfide problem in sewers relates to a complex balance between a large number of wastewater quality-related factors and aspects that depend on the design of the sewer system. The level of the DO concentration in the bulk water, the magnitude of the relevant microbial process rates and exchange rates for... [Pg.136]

FIGURE 6.11. Sulfide production rates in sewers versus wastewater quality characteristics. The results originate from pilot-plant studies (A and B) and field investigations (Cand D) in Japan, Kawasaki town (O) and Oga city ( ). [Pg.165]

Field experiments are generally performed by sampling and measurement in upstream and downstream stations of a sewer network. A volume of water in the sewer can be monitored by following the course of a tracer that is added in an upstream station. Substances like rhodamine, radiotracers and salts may typically be selected for that purpose. Sampling after the passage of such tracers is a convenient way to ensure that corresponding samples are taken and to avoid too much noise because of the variability in wastewater quality. [Pg.174]

It is generally preferred to carry out field experiments in long sewer lines that make it possible to measure relatively large differences in the wastewater quality compared with the level and the uncertainty for determination of the parameters in question. Furthermore, a sewer line without tributary sewers, infiltration and exfiltration must be preferred because of a less complicated sampling program with which to identify all inputs and outputs to the system. [Pg.174]

The results from this study support what has been dealt with throughout the text and especially focused on in Chapter 5 the concept s ability to predict wastewater quality changes in a sewer. The example shows that the corresponding process model can be used to simulate the average dry-weather performance of the sewer and serve as a tool for process design and management. The sewer, with its relation to the subsequent treatment plant, is generally... [Pg.194]

FIGURE 7.12. Results for validation of the conceptual sewer process model for prediction of wastewater quality changes. Measured and simulated absolute values and changes of COD fractions for 29 dry-weather events are compared for wastewater transport in a 5.2 km gravity sewer line from Dronninglund to Asaa. [Pg.195]

STRUCTURAL AND OPERATIONAL IMPACTS ON WASTEWATER QUALITY TRANSFORMATIONS IN SEWERS... [Pg.206]

The impact of the different structural or operational measures on the sewer processes and wastewater quality characteristics can be assessed by model simulation. Examples 8.1 and 8.2 illustrate how structural measures, primarily related to A4 in Table 8.1, affect the in-sewer processes. [Pg.207]

Extension of the WATS model to integrate further dry-weather processes is considered important. Examples of such extensions are the description of the wastewater quality and nitrite/nitrate transformations under anoxic conditions and the emission of hydrogen sulfide into the sewer atmosphere followed by its transformation (oxidation) at the sewer walls. [Pg.212]

The hydraulic performance of sewer pipes can be described at different levels. In the case of nonstationary, nonuniform flow, the Saint Venant Equations should be applied. However, under dry-weather conditions, the Manning Equation is an adequate description of the wastewater flow in a gravity sewer pipe when considering the prediction of wastewater quality changes under transport. There are no grounds for using advanced hydraulic models because of the uncertainties in the prediction of the microbial transformations of the wastewater. [Pg.213]

Keywords Wastewater quality On-site measurement On-line monitoring ... [Pg.244]

The second main reason for wastewater quality monitoring is related to process control, particularly for treatment plants where analysers and sensors are generally used with physico-chemical or biological reactors, including settling tanks. This application is mainly encountered for important wastewater treatment plants, either urban (majority domestic) or industrial, where the storage capacities are rather small with regard to the flow to be treated. Obviously, on-line systems are preferable in this case, but the available instruments often limit the choice. [Pg.245]

Hazards prevention can also be a reason for wastewater quality monitoring, in order to protect biological treatment plants from toxic shock loads, for example, or to prevent potential toxic effects on the receiving medium. This application is mainly found in industrial contexts where the presence of toxic pollutants may occur. In this case, on-line systems are obviously preferable for real-time warning. [Pg.245]

Even if quantitative results are more often expected for wastewater quality measurement, qualitative information is of great interest, as is the case for other applications of the analytical sciences (in the health sector, the use of test kits and biodiagnostic systems leads to quick and useful information, often far from a classical analytical result). In fact, quantitative analysis gives the concentration not only of one substance, but also of a group of comparable substances (surfactants, PAH,...), and even the value of a specific (TOC, TKN,...) or aggregate (BOD, COD, toxicity,...) parameter. In this context, total indices are often proposed as parameters complementary to classical analytical results [1]. [Pg.247]

With respect to wastewater quality monitoring, quantitative and/or qualitative results can be chosen (Table 2). [Pg.247]


See other pages where Wastewater quality is mentioned: [Pg.95]    [Pg.99]    [Pg.100]    [Pg.102]    [Pg.119]    [Pg.129]    [Pg.161]    [Pg.162]    [Pg.195]    [Pg.207]    [Pg.209]    [Pg.247]    [Pg.244]    [Pg.245]    [Pg.245]    [Pg.246]   


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