Study On The Behavior Of Water State In The Aerobic Digestion Of Kitchen Waste

With the development of waste-sorting, the potential recycling of waste significantly improved; at the same time, the demand for disposal of the kitchen waste which were the absolute component of domestic waste, and the high MC often became a bottleneck that the kitchen waste achieved efficient treatment or disposal. To solve this problem, the static analysis and dynamic testing were adopted in this paper, and establishment of water state analysis method, optimization of aerobic digestion system, analysis of water state shifting behavior, and regulation of water state shifting had been used to study the water state shifting in the KW-AD system. The analysis of kitchen waste’s characteristics was based on the kitchen waste which was from community with waste-sorting, and the kitchen waste was with high MC (83.4±3.6%); the EW, CW and MMLW were the main water state in the kitchen waste, the water state distribution of kitchen waste was affected by its components, and the inflection point temperature of EW removal and CW removal were50℃and70℃, respectively, the water state (EW and CW) which could be used by microorganism was more than97%. Compared the dewatering process of kitchen waste, the dewatering processes such as broken, anaerobic digestion, thermal hydrolysis could release part of bound water in the kitchen waste and improve the performance of dehydration of kitchen waste, and the5cm kitchen waste had a good dewatering capability under an optimized thermal hydrolysis condition (150℃,15min); while the MC of kitchen waste after thermal hydrolysis was higher than the applicable MC of KW-AD. The KW-AD with5cm particle size and60%initial MC could have a better performance of the preservation of temperature, the maturity of kitchen waste, the improvement of fertility in the KW-AD system, and there were three water state such as EW, CW and MMLW in the KW-AD. The percentage of EW and CW were affected by DOC, C/N, hemicellulose and cellulose, and the regulation of these characteristics could suppress the water state shifting that the CW changed into EW and achieve the balance of MC in the KW-AD. There were three regulation methods which controlled the behavior of water state shifting in the KW-AD, which were addition of PAM, regulation of aeration, regulation of initial C/N, and these three regulation methods could achieve the regulation of the behavior of water state shifting; but reducing the aeration rate will reduce the supply of oxygen, and the improvement of the maturity had not unrealized in these KW-AD with reducing the aeration rate; the0.1%PAM should be added into the KW-AD when the water had been completely dispersed and the MC had no significant decline, and the regulation of the behavior of water state shifting and improvement of the maturity could be achieved at the same time. And the regulation about the proportion of materials had realized the control of initial C/N in the KW-AD; the high initial C/N suppress the water state shifting, and the initial C/N should be kept in31.0～38.3to achieve a better maturity and an appropriate lag phase of water state shifting. The conclusions obtained in this study may provide theoretical basis for enhancing the effectiveness of KW-AD.