Household food-waste composting using a small-scale composter

Abstract Household food-waste composting is an attractive alternative for Brazilian waste management; however, there are few programs or studies regarding the implementation or management of this small-scale process. This study investigates the performance of food-waste composting using a simple and small-scale domestic composter. Three composting trials were conducted using food waste and wood chips in 10 L plastic bins using different filling schemes. In the first trial, the composter was filled weekly over two months. In the second, the composter was filled once with a mixture of food waste and 100% of the used wood chips from the previous trial. In the last third trial, the composter was filled with food waste and wood chips (50% of wood chips used in the second trial and 50% of untreated wood chips). The physical chemical parameters of the compost were monitored and the total coliforms and E. coli were measured. In all trials, the temperature varied between 26.7°C and 46.2°C throughout the process. The reduction in wet mass was 58-69%, while the reduction in dry mass was 37-61%. The pH value, the contents of carbon and nitrogen and the C/N ratio were in accordance with the values recommended in norm 25 (July, 2009) adopted by Brazil's Agriculture Ministry. Only the compost from Trial 2, which had 1900 MPN g-1 total solids, did not meet the E. coli standards; this was likely due to the fact that when the temperatures did not reach the thermophilic phase, the relatively long time the waste remains in the composter allows these pathogenic microorganisms to decay naturally.

摘要 家庭厨余堆肥是巴西垃圾管理领域颇具吸引力的替代方案，但目前针对该小型化堆肥流程的实施与管理相关项目及研究仍较为匮乏。本研究针对一款简易小型家用堆肥装置的厨余堆肥效能展开探究。实验采用10升塑料桶作为堆肥容器，以厨余垃圾与木屑为原料，设置三种不同的投料方案开展三组堆肥试验。第一组试验中，堆肥装置每周投料一次，持续两个月；第二组试验则一次性投料，将厨余垃圾与第一组试验中使用过的全部木屑混合后加入堆肥桶；第三组试验的投料为厨余垃圾与木屑的混合物，其中木屑包含50%第二组试验使用过的木屑以及50%未使用过的新鲜木屑。研究对堆肥的理化参数进行了监测，并检测了总大肠菌群与大肠杆菌（E. coli）的含量。所有试验的堆肥全程温度均维持在26.7℃至46.2℃之间。堆肥物料的湿重减重率为58%~69%，干重减重率则为37%~61%。堆肥的pH值、碳含量、氮含量及碳氮比（C/N）均符合巴西农业部于2009年7月颁布的第25号标准中的推荐值。仅第二组试验产出的堆肥（总固体中大肠杆菌数为1900 MPN·g⁻¹）未达到大肠杆菌限值标准，其原因可能为：该组试验的堆肥温度未达到嗜热阶段，而物料在堆肥装置内的停留时间较长，使得病原微生物自然衰减。