Home-made compost's quality: A review

Society is reconsidering composting, this ancient technology, for the treatment and recycling of municipal organic wastes. Municipalities are now encouraging the use of home composting when very little is known about the environmental impact of this practice as compared to other more conventional means. Furthermore, there is a need to establish a standard method to evaluate the impact of such a practice, when the diversified tools presently used produce data which cannot be compared. Within the European LIFE project Miniwaste, a study was conducted to establish a standard method to evaluate the mass and composition of the treated biowaste. The experimented method used a combination of well recognized tools: conducting household surveysgetting households to measure the mass of biowaste (BW) fed into the composters, andmeasuring household waste production and its residual organic fraction (ROF). The study of the results obtained thanks to these different tools enabled to propose a simplified protocol that will then be used by other municipalities to assess the impact of home composting in their own communities and compare their results with other European regions. The study was conducted in the sector of Cesson Sévigné, a suburb of the City of Rennes, France. Within the 1000 households contacted, all living in individual homes, 300 were surveyed to characterize their organic waste (OW) management practices. People of 60 years and over were found to be most likely to practice composting. The telephone survey was also used as a simple tool to recruit households to further the study and monitor the mass and type of biowaste actually composted. Accordingly, 38 households volunteered (VH) to weight their fed biowaste during one year: the OW originated either from their kitchens or their yards. 4 parallel campains of household waste characterization (one per season) were conducted. The amounts of organic waste still present in the bins are recorded according to the bio-waste management reported by households. Groups were established to separate households that compost and weigh their composted waste (VH) from, those who compost but do not weigh their waste (NVH) and those who do not compost. The statistical analysis of the results determined differences due to the seasons, to the fact of being weighing volunteers or to practice or not home-composting. It appears that each individual assessment tool does not provide a complete response to the evaluation. Therefore the coupling of several tools is recommended. Finally, the method proposes to implement a survey and measure the output per capita for households 'composters' and 'non-composters.