Assessment of industrial solid waste management and resource recovery practices in Tanzania

A study on industrial solid waste management (ISWM) and resource recovery practices was carried out in Dar es Salaam City, Tanzania. Practices pertaining to generation, storage, collection and transportation, processing, and final disposal were investigated. The ISW was also quantified and characterised. It is observed that 89% of sources of ISW produce process solid waste only while the remaining 11% produce a mixture of process and non-process ISW. ISW is stored in open-air piles, bins, masonry enclosures, and silos. Collection of ISW is done by the source industries (60%) and private contractors (40%). The total ISW generation rate is 39,000 tonnes/yr and of this 91.7% comes from food and beverage industries. Although formal cleaner production technologies (CPTs) are practiced by only a handful of industries, many industries practice both intra- and inter-industry reuse and recycling. The commonest reusable and recyclable materials are glass cullets (60.7%) and spent grain and yeast (21.6%). Notably, all glass cullets are recycled. The most problematic stage of ISWM is disposal, which is not done in a sanitary manner. Also, the fact that the hazardous component of ISW is not segregated for proper and separate handling is a potential cause of health and environmental problems. Notable observations in this study are: (1) cleaner production is practiced much more extensively than reported and (2) resource recovery has a considerable potential of improving ISWM, especially in developing countries since most of the ISW components are reusable or recyclable.