二氧化锰对微好氧堆肥腐熟、温室气体及臭气排放的影响

Effects of manganese dioxide on composting maturity,greenhouse gas and odor emission of multi-organic solid waste micro-aerobic composting

为探究锰矿物添加对微好氧堆肥过程腐熟、温室气体和臭气排放的影响,该研究以由厨余垃圾、水稻秸秆、羊粪和尾菜组成的多元混合物料堆肥为研究对象,共设3个处理,采用间歇通风方式,将通风速率为0.14 L/(kg·min)设置为好氧堆肥对照(CK),速率为0.06 L/(kg·min)为微好氧处理(T1),添加二氧化锰(MnO_(2))的微好氧处理为T2。结果表明:多元废弃物好氧或微好氧堆肥在堆制70 d后均能腐熟,但T2处理腐熟度显著高于T1。微好氧处理T1、T2减少了26.47%~30.29%的NH3和33.19%~38.60%的N_(2)O的排放,总温室效应减少了29.26%~31.38%。臭气的排放集中在前14 d,T1、T2处理的H2S和VOCs的释放量显著增加了320.35%~501.04%和39.82%~53.63%。因此,微好氧堆肥可达到减排目的,但却加剧臭气的排放;MnO_(2)可提高促进堆肥腐熟,降低温室气体和臭气的排放。

In the process of aerobic composting,a large amount of volatile gas will be produced,which will cause harm to the environment,lead to the serious loss of carbon,nitrogen and other nutrients,and affect the improvement of organic fertilizer quality.Studies have shown that by adjusting the ventilation rate and additive during composting,pollution gas emissions can be reduced,and carbon and nitrogen elements can be fixed to improve maturity.In order to explore the effects of manganese mineral addition on maturity,greenhouse gas and odor emissions during micro-aerobic composting,three treatments were set up in this experiment with the multi-component mixture composting composed of kitchen waste,rice straw,sheep manure and vegetable waste as the research object.During the whole composting period,all treatments were forced intermittent ventilation.The ventilation rate was set to 0.14 L/(kg·min)as the aerobic composting control(CK),the ventilation rate was 0.06 L/(kg·min)as the micro-aerobic treatment(T1),the ventilation rate was 0.06 L/(kg·min)and the addition of manganese dioxide(MnO_(2))was T2 treatment,and each treatment was repeated twice.The ventilation cycle was one hour,and 10 minutes of air was ventilated every 50 minutes in the first 16 days.In order to make the compost material mature smoothly,the ventilation cycle was adjusted to 20 minutes of air every 40 minutes on the 17th day.The composting experiment was carried out in six 50 L closed fermentation tanks.Through the determination of maturity indexes such as germination index and electrical conductivity,it was shown that after 70 days of composting,all the treatment materials were basically transformed into mature compost.The results showed that aerobic or micro-aerobic composting of multiple wastes could transform the materials into compost,but the quality of final compost products in T2 treatment was significantly higher than that in T1 treatment.Both T1 and T2 treatments could reduce the emissions of NH3 and N_(2)O to varying degrees.Compared with CK treatment,the emissions of NH3 in T1 and T2 treatments decreased by 30.29%and 26.47%,respectively,and the emissions of N_(2)O decreased by 33.19%and 38.60%,respectively.However,the CH4 emissions increased by 127.22%and 87.58%,respectively,and the total greenhouse effect T1 and T2 treatments decreased by 29.26%and 31.38%,respectively,compared with CK.The emission of H2S and volatile organic compounds(VOCs)in odor(OC)was concentrated in the first 14 days,and the emission of H2S and VOCs in T1 and T2 treatments under low ventilation rate increased significantly,and the emission of H2S increased by 501.04%and 320.35%respectively compared with CK.VOCs increased by 39.82%and 53.63%,respectively.Therefore,microaerobic composting can achieve the purpose of emission reduction,but the reduction of ventilation rate will aggravate the emission of odor;the addition of MnO_(2) can improve the maturity of micro-aerobic composting to a certain extent and reduce the emission of greenhouse gases and odors,which can provide technical support for the efficient resource utilization of multi-organic wastes and the synergy of pollution reduction and carbon reduction.