| A mass of sludge will accompany with biological process in wastewater treatment process. The series of sludge treatment including separation, stabilization, digestion, dewatering and disposal usually lead a high cost in civil construction and operation. Moreover, the disposal of sludge faces more and more challenges. Accordingly, the topics about the effective technique of sludge reducing, stabilization and disposal are got much attention currently. The technique of hybrid biofilm reactor (HER) sludge aerobic digestion was developed from the background mentioned above. The conclusions were drawn as follow through the research of HBR:(1) Under the room temperature (21~23℃), the time of stabilization in HBR sludge aerobic digestion reactor was three days less than traditional sludge aerobic digestion reactor. Therefore, compared with the CAD technique, the velocity of sludge digestion of HBR technique was improved. The volume of reactor, the cost of reactor and the energy consumption of sludge digestion were also reduced.(2) Because of the biofilm in HBR technique, the diversity of microenvironment attendant in the reactor was benefit to the growth of metazoan which required more nutrition in comparison with other microorganism, enhancing the rate of endogenesis inspiration and preying process. At the same time, the biomass was decreased rapidly and the efficiency of sludge digestion was improved.(3) For HBR process, the removal efficiency of MLVSS decreases with the increase of undigested sludge concentration, while the removal quantity increases with the increase of undigested sludge, showing a proportional relationship. So the lower sludge concentration is better in HBR technique. We may cancel sludge thickener in project design and save investment of the project. The sludge digested effectly and speed are affected litter by aerating intermittently or continuously, so it has saving meaning that using aeration intermittently. It is obvious that the sludge digestecd effect is influenced by the temperature in the HBR technics. It is that, conditioning the microorganism fixity, the sludge activeness is higher still and the digested speed is faster still due to the temperature rising more and more.(4) The sludge digestion stability would be achieved in about seven days with the optimized parameters of intermittent HBR sludge aerobic digestion reactor The optimized parameters mean the constant temperature of 30℃, the intermittent aeration,the low concentration of sludge in the beginning, no limit in PH ). It was also found that the challenge of further degradation after the sludge stabilization was not be conquered by prolonging the sludge retention time (SRT)(5) It is suggested that adopting continuous HBR technics in the actual engineering. The cubage load of the continuous HBR technics is 0.51 kg MLVSS/ (m3 d) if it run in the prime condition. The water index of the outflow is affected greatly by the sludge characters, but the circumfluence of the outflow don't impact greatly the sewage plant's run.(6) the dynamics model of the arrobic digestion by using continuous HBR:(7) Calculating with 50m3/d surplus sludge, the project investment of HBR technics reduce 13% than that of the CAD technics, and the run expense of the HBR reduce 18% than that of the CAD. These show that HBR technics is feasible on technique and economy.
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