A comparative study was run during 13 months on two biowaste definitions involving both lab tests and field surveys. A narrow biowaste definition, allowing only biogenic wastes was compared to a broad biowaste definition, including compostable man-made products, such as non-recyclable wastepaper and diapers. Two similar real-life test areas with each about 425 inhabitants were defined in a semiurban area North of Antwerp. During the whole test period the amount of curbside waste, this is biowaste and restwaste (the ‘non-biowaste’), was continuously and precisely measured and also analysed regularly (twice per season) for composition. At the start, middle and end of the test, surveys were held with a questionnaire for the population of each test area. In each season of the year, bench-scale aerobic composting experiments were run to evaluate the influence of both biowaste definitions on the composting process and the compost end product.The introduction of source-separated waste collection resulted in an overall landfill diversion of 43% for the narrow biowaste definition and 46% for the broad biowaste definition. The contamination of biowaste (about 3%) was low for both definitions, the restwaste (or so-called grey waste) still contained a lot of organics (34 to 66%). Supposing that the collection and the appropiate disposal of organics could be improved to 95% efficiency (compared to about 60% currently), the landfill diversion could be increased to 59% for the narrow and 74% for the broad definition. Whereas the average efficiency of separate collection of organics is about 61%, it is 49% for non-recyclable paper and even about 20% only for certain categories of compostable, non-recyclable paper. Apparently some more education or a better system of recognition and identification is needed to improve the collection efficiency of man-made compostables.The acceptance and goodwill of the population was significantly higher for the broad biowaste definition, especially in the summer months. The yearly, overall composition of the total curbside waste (biowaste and restwaste combined) is 17% kitchen organics, 47% yard waste, 4% recyclable paper, 13% non-recyclable paper and 19% non-compostables. It must be mentioned that glass, paper and large yard waste are collected separately by a voluntary bring-system. The broad biowaste typically contained 16.0% paper (of which 2.9% was recyclable) versus 2% for the narrow (0.3% recyclable).The aerobic composting process was improved by expanding the biowaste definition through easier moisture control, better aeration and a more tempered pH evolution. A significant difference was seen for NH3 and corresponding odour emission, being much lower in the broad definition. The quality of the compost produced was similar and acceptable for both biowaste definitions.
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- Results of Laboratory and Field Studies on Wastepaper Inclusion in Biowaste in View of Composting
B. De Wilde
L. De Baere
- Springer Netherlands