Aerobic waste treatment system

Figure 13. Single-stage aerobic waste treatment system. So = influent BOD, Sg = effluent BOD, Xr recycle biomass concentration (VVS), rF = recycle flow rate, wF = wasting rate.

Figure 14. Combined anaerobic-aerobic waste treatment system...

Colox An aerobic biological treatment system for municipal and industrial wastes. The biomass is fixed as a film on granules in a fixed bed. Developed in Texas by Tetra Technologies. 

It should be noted that full treatment of the waste could be accomplished with a retention time of approximately 5 min when only 0.8 U/mL of crude or pure enzyme were used in the presence of PEG. In contrast, an aerobic biological treatment system that was used to treat this particular foundry waste required a retention time of approximately 6 hr. This illustrates one of the most significant advantages of enzymatic treatment. On the other hand, the use of crude enzyme preparations and PEG contributes significant quantities of organic compounds to the waste, which ultimately must be removed in a subsequent treatment step. 

Determination of Kinetic and Stoichiometric Pseudo Constants As indicated above, these parameters are most important for predicting the performance of biologically based treatment systems. It would be ideal if tabulations of these were available for various industrial wastes as a function of pH temperature and nutrient levels. Unfortunately, little reliable data has been codified. Only certain trends have been established, and these are primarily the result of studies on municipal wastewater. For example, the yield coefficient Y has been shown to be much higher for systems that are aerobic (molecular oxygen as the electron acceptor) than for anaerobic systems (sulfate or carbon dioxide as the electron acceptors). Systems where oxidized nitrogen is the electron acceptor (termed anoxic) exhibit yield values intermediate between aerobic and... 

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