碳氮比对蔬菜废弃物好氧发酵腐熟度及臭气排放的影响

为了提高蔬菜废弃物发酵效率、减少臭气排放、确定其好氧发酵最佳碳氮比,以蔬菜废弃物为主料、猪粪和玉米秸秆为辅料进行好氧发酵,设置C/N为20、25、30 3个处理,探讨不同C/N对发酵产品腐熟度及臭气排放浓度的影响,以温度、含水率、pH、电导率(EC)、腐植酸光学特性(E₄/E₆值)、种子发芽指数以及全氮、全磷、全钾含量变化评价发酵产品的腐熟度。T1处理(C/N为20)高温期持续时间最长为6 d,种子发芽指数最高为82.23%,其腐熟效果最好,且全氮、全磷、全钾含量分别提高了24.22%、78.94%、51.45%; 从臭气排放浓度来看,T2 (C/N为25)处理组NH₃排放浓度最高达368000 μg/m3,T3(C/N=30)处理组H₂S排放浓度最高达671 μg/m3,TI处理TVOC排放浓度最高,但最高与最低排放浓度差仅为4.3×10-6。因此,建议蔬菜废弃物、猪粪、玉米秸秆联合好氧堆肥的C/N为20,可满足好氧发酵无害化和减少臭气排放的要求。

EFFECTS OF CARBON TO NITROGEN RATIO ON MATURITY AND ODOR EMISSION IN AEROBIC FERMENTATION OF VEGETABLE WASTE

In order to improve the fermentation efficiency of vegetable waste and reduce the emission of odor to determine the optimal carbon nitrogen ratio of aerobic fermentation. Aerobic fermentation was carried out with vegetable waste as the main material, and pig manure and corn straw as the auxiliary materials. Three C/N ratios (20, 25 and 30) were set to investigate their effects on maturity and odor emission concentration of fermented products. Temperature, moisture content, pH, electrical conductivity (EC), E4/E6, seed germination index and total nitrogen, total phosphorus and total potassium content were used to evaluate the maturity of fermented products. The results showed that: in T1 treatment (C/N=20), the longest duration of high temperature period was 6 days, the seed germination index was up to 82.23%; then its maturation effect was the best, and the content of total nitrogen, total phosphorus and total potassium were increased by 24.22%, 78.94% and 51.45% respectively. In terms of odor emission concentration, the highest emission concentration of NH₃ appeared in T2 (C/N=25) treatment group, 368000 μg/m3, the highest emission concentration of H₂S appeared in T3 (C/N=30) treatment group, 671 μg/m3; the highest TVOC emission concentration appeared in T1 treatment group, but the maximum difference of TVOC emission concentration between all groups was only 4.3 ppm. Therefore, it was suggested that the optinum C/N ratio of vegetable waste, pig manure and corn straw combined with aerobic compost was 20, which could meet the requirements of harmless aerobic fermentation and reduce the emission of odor.