| In order to reduce emissions of odorous（such as H2S and NH3） substance during kitchen waste compost, a series of researches consisted with 4 experiments are designed to find out the effects on emissions of H2S and NH3 by changing the parameters during composting process in this paper. In the first experiment, we use kitchen waste as comparison, and other treatments add corn straw, woody peat and sawdust as amendments co-compost with kitchen waste to determine the best amendment for following experiments. In the second experiment, we use the best amendment in the first experiment to co-compost with kitchen waste to find the best ventilation rate. In the third experiment, we change the ventilation modes and intensions to confirm the best ventilation modes base on the same ventilation quantity. In the final experiment, we synthesize the best indexes chosen by experiments above, and set up different kinds of turning frequency to find the best turning frequency in kitchen waste composting. The results of experiments are as follows:（1） The first experiment: choose the best amendment. The use of amendments could reduce emissions of H2S and NH3 during kitchen waste composting in varying degrees. In the treatments with corn straw, woody peat and sawdust as amendments, sawdust could control emissions of H2S best, while as woody peat could control emissions of NH3 best. But in analysing process of phytotoxicity indexes, treatments with woody peat and sawdust only reached the innocuous requirement, and the treatment with corn straw reached the standard of maturity completely. Since emissions of odorous substance and harmless of composting product are equally important in composting experiment, and amendments sources and prices must be take into consideration too. So corn straw was chosen to be the best amendments in this experiment.（2） The second experiment: choose the best ventilation rate. Four treatments set different ventilation rate（0.5m3/h, 1 m3/h, 2.2 m3/h and 3.2 m3/h） during kitchen waste and corn straw co-compositing respectively. The results show that the emissions of NH3 are increased along with the increase of ventilation rate. The emissions of H2S are declined with the increase of ventilation rate Within a certain range, and excessive ventilation rate would increase the emissions of H2S. It can be seen that the emissions of H2S and NH3 are less with the ventilation of 2.2 m3/h. So we chose 2.2 m3/h as the best ventilation rate in this experiment.（3） The third experiment: Choose the best ventilation mode. Due to ventilation of 2.2 m3/h（ventilate sustained whole day） is the best choose in the second experiment, so base on the same ventilation quantity per day, and change ventilation modes to find out the most appropriate ventilation to reduce the emissions of H2S and NH3. We set up four treatments with different kinds of ventilation modes which are 0.5m3/ h（ventilate sustained whole day）, 2.2m3/h（ventilate sustained whole day）, 3.3m3/h（ventilate shutoff 20 min and turn on 40 min） and 6.6m3/h（ventilate shutoff 40 min and turn on 20 min） respectively in this study. The emissions of H2S are declined along with the increase of instantaneous ventilation rate, and the ventilation of 0.5m3/h（ventilate sustained whole day） has the lowest emissions of NH3. Ventilation of 6.6m3/h（ventilate shutoff 40 min and turn on 20min） has the highest emissions of H2S and NH3, The emissions of H2S and NH3 in other two treatments almost the same quantity. Only treatments with ventilations of 2.2m3/h（ventilate sustained whole day） and 3.3m3/h（ventilate shutoff 20 min and turn on 40 min） reached the standard of maturity, and temperature of ventilation of 3.3m3/h（ventilate shutoff 20 min and turn on 40 min） is close to ambient at the 21 st day, and this kind of ventilate conducive to rapid composting. Ventilation of 3.3m3/ h（ventilate shutoff 20 min and turn on 40 min） chosen as the best ventilation mode finally.（4） The fourth experiment: Choose the best tuning frequency selection. Apply the best composting parameters chosen in former experiments. We set up 4 different kinds of turning frequency（twice a week, once a week, once every two weeks and never turning） in this experiment. The result shows that turning frequency has few influence to the emissions of H2S, the emissions of NH3 had an obvious reflect. We choose turning material weekly frequency as the best choice in this experiment comprehensive harmless index and the emissions of H2S and NH3.In conclusion, we use corn straw co-compost with kitchen waste, and set ventilation at 3.3m3/h（ventilate shutoff 20 min and turn on 40 min）, and turn material once a week have the best effect in reduce the emissions of H2S and NH3 during kitchen waste compost. |
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