Sludge aerobic

Additional experiments with high concentrations of 2,4-D butoxyethanol ester with and without buffers showed no difference in degradation rates which confirmed the observations made in field experiments. Based on interpretation of results of these laboratory studies, combinations of buffers, anaerobic sludge, aerobic slime, light and constant mixing were not considered to be necessary for small and intermediate sized disposal systems. 

Three different process configurations have been studied (see Fig. 1) in all cases 2 1/d of OOWW (average composition in Tab. 1) were diluted 1 8 with tap water (which simulated a settled municipal sewage) and treated anaerobically with a UASB pilot reactor. The anaerobic effluent was then submitted to a single stage activated sludge aerobic treatment directly (Fig. 1 A), or after further 1 3 dilution with tap water (Fig. IB). Alternatively, the anaerobic effluent was submitted to a two stages aerobic treatment (Fig. 1C). 

The following conclusions emerged after submitting OOWW, diluted 1 8 with tap water (which simulates settled municipal sewage) to a UASB anaerobic treatment followed by activated sludge aerobic post-treatment ... 

D5209-92 Test method for determining the aerobic biodegradation of plastic materials in the presence of municipal sewage sludge Aerobic n o... 

Sizing activated sludge aerobic biological purification facilities... 

In aerobic processes, the mean sludge residence time is typically 5 to 10 days. The hydraulic residence time is typically 0.2 to 0.3 days. Suspended growth aerobic processes are capable of removing up to 95 percent of BOD. 

In all types of biological processes, excess sludge is produced which must be disposed of. The treatment and disposal of sludge are major problems which can be costly to deal with. Anaerobic processes have the advantage here, since they produce considerably less sludge than aerobic processes (on the order of 5 percent of aerobic processes for the same throughput). 

ASTM D5271-93 aerobic activated sewage sludge O2 and CO2... 

The microorganisms grow in response to the food source suppHed in the wastewater and produce more biological sludge than is needed to maintain the process. This excess sludge must be wasted from the process and is usually treated by dewatering and aerobic or anaerobic digestion. 

Biolog ic lRemoval. Certain organisms normally present in activated sludge have the abiUty to store phosphoms. The process configuration for bio-P removal involves an anaerobic step in which phosphoms is released and acetate taken up by the bio-P organisms. This is followed by an aerobic step in which phosphoms is rapidly taken up by the bio-P. Under proper operating conditions, soluble effluent phosphoms levels of 0.1 mg/L are achievable from municipal wastewater. 

Sludge Stabilization. Organic sludges need to be stabilized before ultimate disposal except in the case of incineration. This is usually achieved by either aerobic or anaerobic digestion. In aerobic digestion, the degradable volatile soHds are Hquefted and oxidized to CO2 and H2O. In anaerobic digestion the soHds are Hquefted and fermented to CH and CO2. 

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 3. Comparison of Filters on Aerobically Digested Sludges ...

The four most common aerobic biological treatment processes are stabilization ponds, aerated lagoons, trickling filters, and activated sludge (see... 

A new concept is to use an on/oFf air supply cycle. During aeration, nitrates are produced. When the air is shut off, nitrates are reduced to nitrogen gas. This prevents acid buildup and removes nitrogen from the sludge. High power cost for aerobic digestion restricts the applica-bihty of this process. 

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