Development And Application Of A Pyriform Rotating Drum Reactor For Aerobic Composting In Pilot Scale

Based on the results of material and heat balance as well as the optimization ofwind pressure and agitator, a pyriform reactor was developed to make it more suitablefor the aerobic composting. The reactor is mainly composed of a pyriform rotating drum,two shaftless spiral guide vanes, ventilation systems, power devices and monitoringsystem. The reactor has the advantages of the high mobility and more convenience tothe material in and out. The reactor core is a spiral guide vane pyriform-shaped cylinderand cylinder axis hollow, driven through the external drive gear. In the spiral duct guideand material weight below joint action, can make the material rise and fall and agitationin different direction repeatedly, make the material and the drum into the air fully rollcontact. The results showed that the level of mix uniformity rate of up to90%after5min stirring, reached the mixing uniformity requirements.With the new aerobic composting reactor, experiments studied the treatment effectof human feces. In order to determine the optimal ventilation rate, the experiments wereon certain mixing intensity and mixing time conditions, contrasted the materials heatingrate, degradation effect, maturity and other indicators of three different ventilation rate(0.7L/min,1.5L/min,3L/min) and without forced ventilation. The results show thatunder the conditions of the ventilation rate1.5L/min, the pile to heat up quickly, after15days composting reaction, the TOC and COD removal rates were47.85%and63.03%,less loss of nitrogen, pH value was maintained at about8, GI was95.6%, reachedmaturity requirements. Followed by0.7L/min,3L/min ventilation rate, without forcedventilation compost effect was the worst. The ventilation rate of1.5L/min can be usedas the optimal ventilation rate for aerobic composting reactor. Under the condition of1.5L/min of ventilation rate, a study in pilot-scalesequencing batch feeding for human feces composting was carried out. The resultsshowed that the effect of sequencing batch compost is much better than batch compost.In the sequencing batch compost, the pile temperature can be up to50℃on thesecond day and maintained for30days, the TOC and COD removal rates were60.86%and61.14%, pH value was maintained at about8, GI was92.18%. After the aerobiccompost, the composting materials was stability with the smell of moist soil, thecolor was brown, no toxicity to plants and can fully reach the composting standard.The results prove that the new aerobic composting reactor has a good effect for thetreatment of fecal waste. The new aerobic composting reactor can significantly improvethe excreta disposal rate, reduce the waste treatment facilities investment and runningcost, after composting, the composting materials can be used as organic fertilizer, whichcan effectively reduce, control of ecological environment and human health risks, havehigher promotion value and market prospect.