石灰投加与搅拌对生态厕所的灭菌效果

Effect of lime addition and mixing on pathogen inactivation in a composting toilet

以发展中国家农村地区的卫生条件改善为目的,开展了简易生态厕所的粪便堆肥处理实验。在投加石灰作为抑菌剂的条件下,研究了搅拌混合对杀灭致病微生物的影响,以及使堆肥终产物达到可接受风险值所需的最佳搅拌条件。实验确定了石灰的投加量,并应用Beta-Possion模型对堆肥处置过程中致病微生物对暴露人群的健康风险进行评价,从而从健康风险控制的角度确定了最佳的搅拌次数。研究结果表明,石灰投加量约占堆肥干重1.5%,手动搅拌50次,经搅拌后放置12 h能达到可接受的风险值(3.2×10-5)。

In order to improve the sanitary condition in rural area in developing countries,an experimental study was conducted on feces treatment using a simple composting toilet with lime addition and manual mixing.The objective was to find the optimal condition for reducing the pathogenic risk to the acceptable level. The BetaPossion model was used for evaluating the health risk on exposure to the pathogens residual in the composting product. As a result,it is found that the acceptable infection risk of 3. 2 × 10-5can be achieved under the conditions of lime addition to 1. 5% of the total dry weight of the compost,manual mixing for 50 times,and reaction time for 12 h.