Process Options for Water Reclamation

In this section, the options for sewage treatment are investigated, including MF/UF filtration, but without RO. The two primary options shown are conventional activated sludge (CAS) followed by tertiary filtration (TF) and integrated membrane bioreactor (MBR). These options are developed and costed for plants ranging in size between 3800 mVday (1 MOD) and 76,000 mVday (20 MOD). 

The process conditions used to design the plants are summarized in Table 7.3. For the conventional activated sludge system, typical values for North American design were selected by using most of the default values suggested by CapdetWorks. The same sludge age [solids retention time (SRT)] was used for CAS and MBR, but hydraulic retention times and mixed liquor concentrations were significantly different. 

TABLE 7.3 Design Process Conditions for Sewage Treatment Plants 

Unit Process Parameter Units Small Plants 19,000 mVday CAS-TF MBR Large Plants 19,000 m /day CAS-TF MBR  

Sludge digestion HRT day Aerobic 15 Aerobic 15 Anaerobic 35 Anaerobic 35 

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