High-solid Anaerobic Digestion Of Sewage Sludge:Feasibility Study

With economic development, the disposal of solid waste, has shifted from the pollution control to resource development. The organic waste into bio-energy has become a hot issues for organic solid waste treatment and disposal. Sludge land utilization is restricted by stricter environment limitation. Thermophilic anaerobic digestion has been emphasized in Europe and America. The dewatered sludge anaerobic digestion should improve the unit content of organic matter and reduce the volume of the reactor. Hydrogen peroxide pretreatment, can accelerate the hydrolysis process, shorten the digestion time, reduce the volume of the reactor, and improve the methane yield.The trials that study the main factors of dry anaerobic digestion process, mechanism and process operating parameters, the formation of a viable urban sludge dry fermentation technology route; Researching feasibility of the Quick start, and operating parameters optimized to enhance the performance of anaerobic digestion, to maximize the extraction of biomass energy. Provide strong technical support for dewatered sludge stabilization treatment. Experimental results show that:Short residence time (20days), high load start, ammonia concentration is high and VFAs easier to accumulate large extent, but alkalinity is high, pH did not change significantly, so does not produce suppression. When the load of2.78g/(L-d),3(20starts) with the other reactor gas production rates are around6.0L. Load of3.71g/(L·d), gas production rate of7.8L, more than the theoretical value. When the load increased to5.59g/(L-d), production rate of12L. Biogas has a high methane content.Biogas day generation, VS degradation rates, gas production rates of thermophilic anaerobic digestion are higher than the mesophilic anaerobic digestion, thermophilic anaerobic digestion is more than5%. Both biogas methane have the same content. The high temperature reactor ammonia concentration was significantly higher than the temperature reactor, but this concentration did not affect the stability of the system, in the same ammonia concentration, the concentration of free ammonia of thermophilic anaerobic digestion is twice that of mesophilic anaerobic digestion, thermophilic anaerobic digestion VFAs concentration was significantly high than mesophilic. However, the alkalinity of is also higher, and therefore did not cause a reduction of pH.Hydrogen peroxide pretreatment, can destroy the floe and microbial cell structure, intracellular material from the solid phase into the liquid phase. TOC and proteins, polysaccharides are increased with the increase of the heating time and H2O2dosage. When the dosage greater than1.6mL/50g-Sludge, the increase of the concentration begun to flatten. Hydrogen peroxide treatment, VS with H2O2dosage increases. If the heating time is more than40minutes when the dosage is greater than1.6mL/50g-Sludge, VS content is low, not conducive to anaerobic digestion. Hydrogen peroxide treatment can reduce the viscosity of dry sludge, can effectively improve the efficiency of anaerobic digestion and the rate of gas production.