Ingenieur Vol. 64 Oct-Dec 2015 Ingenieur Vol 64 Oct-Dec 2015 | Page 49

Various types of household waste collection schemes, this is a major challenge in relation to the proper management of household waste. In developing countries, it is more common practice to separate and reuse all valuables from household waste. Collection and Transport Households usually keep waste to be discarded in designated containers. These may be metal or plastic dust-bins or plastic and paper bags. In large buildings and apartment blocks, centralized containers are sometimes provided into which occupants place their waste. In most developed countries, it is usual for household waste to be collected from premises on a regular basis since food waste, in particular, decays rapidly. In cities and urban areas, waste is collected for disposal in specially designated vehicles fitted with compaction equipment to increase the payload, which can be transported, often over significant distances to sanitary landfill site. In large conurbations, it has been found economically viable to transfer the collected waste to railway containers for transport to a landfill site; large barges are also used for transport on water. In some instances, waste is bailed to facilitate mechanical handling. Recovery Operations The next important principle in respect of waste avoidance and minimization is recovery of recyclable components to the greatest possible extent. In many industrialized countries, sophisticated recovery programmes have been introduced for household waste. Nevertheless, too many valuable resources are still lost from inadequate separation, collection and recovery systems, most often due to the unsustainable market for several recovered waste materials. In some developing countries, components of waste streams are usually segregated and used. Combustibles may be used as fuel either as such, or after densification. Paper may be used in smallscale paper/cardboard making and plastic wastes can also be reused in applications not requiring high quality and clean material. 47