Sludge processing

Process Va.ria.tlons, There are many variations of the activated sludge process which have been developed in response to different wastewater... 

In the activated sludge process, performance is related to the food-to-microorganism ratio (F/M), which is the kg BOD appHed/d/kg volatile suspended soHds (VSS). 

Fig. 13. Types of activated sludge processes (a) plug flow (b) complete mix (c) selector-activated sludge.

Chemica.1 Remova.1. Phosphoms can be precipitated with lime to form Ca2(P0 2- The actual composition of the precipitate is a complex compound called apitate. Achieving minimum phosphoms concentrations requires a pH in excess of 10.5. Alum or iron will precipitate phosphoms as AIPO4 or FePO. This procedure is generally employed in conjunction with the activated sludge process, in which the coagulant is added at the end of the aeration basin or between the aeration basin and the final clarifier. 

Activated Sludge. There are several generic activated sludge processes presendy available. Complete Mix (CMAS) is appHcable to refractory-type wastewaters in which filamentous bulking is not a problem. This process has the advantage of dampening ductuations of induent wastewater quaUty. 

The BPT is defined as the level of treatment that has been proven to be successful for a specific industrial category and that is currendy in fuU-scale operation. Sufficient data exist for this level of treatment so that it can be designed and operated to achieve a level of treatment consistendy and with rehabUity. For example, in the pulp and paper industry, BPT has been defined as biological treatment using the aerated lagoon or the activated sludge process with appropriate pretreatment. 

Fig. 2. Typical flow sheet for a domestic wastewater treatment plant utilizing the activated-sludge process.

Fig. 3. Process components for the activated-sludge process, with aerobic digestion at plants <473.1 m /h and two-stage anaerobic digestion at plants...

Table 5. Design Parameters for the Activated-Sludge Process ...

Fig. 4. Contact stabilization plant. Conventional activated-sludge process. The reaeration and contact tanks can be replaced by an aeration tank (21).

Trickling Filters. The so-called trickling filter is not a filter but a bed of stones or other coarse material (packing) over which the sewage flows. In terms of the total number of installations, it is the most widely used biological treatment process. However, the greatest total volume of waste is treated by the activity-sludge process (12). 

G. M. Shaul, R. J. Lieberman, C. R. Dempsey, and K. A. Dostal, "Eate of Azo Dyes in the Activated Sludge Process," presented at the 41st Annual Purdue Industrial Waste Conference, Purdue University, West Lafayette, Ind., May 13—15, 1986. 

FIG. 25-54 Schematic diagrams of various modifications of the activated-sludge process, a) Conventional activated sludge. (h) Step aeration, (c) Contact stabilization, (d) Complete mixing, (e) Pure o gen. (f ) Activated hiofiltration (ABF), (g) Oxidation ditch. 

Figure 1. Simplified process flow sheet of activated sludge process.

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