Recycling and composting should be preferred processes

Perilous waste and its disposal perhaps is the greatest problem before the mankind in today's world. Increasing waste generation in the present time is associated with voracious consumer culture and human greed, which have done irreparable damage to the environment.
Human activities generate wastes. Most of these wastes are normally solid and the meaning of the word waste suggests that the material is useless and unwanted. But many of these waste materials can be reused and thus can become a resource. Environmental pollution due to waste, whatever may its source be, has reached menacing dimensions. The wastes associated with environmental problems have revealed that greater emphasis must be given to the management of urban solid wastes and their by products.
The solid wastes generated from different sources are highly heterogeneous in their physical, chemical and biological properties and call for different methods for their safe disposal. Solid wastes comprise countless number of different components: dust, discarded food, papers and boards, metals, plastics and glass, cloth and furniture, garden wastes, and many hazardous substances. In most cities of Bangladesh, the decomposable organic matter is the major component of the municipal refuse and makes up nearly 70 to 80 percent of it. This component of solid waste when left uncleared starts decomposing emitting foul odour and it also leads to breeding and proliferation of undesirable and disease causing organisms. The most poignant environmental damage caused by solid wastes is to its aesthetics and hygiene.
Many people feel that solid waste management is a simple affair -- simply putting it onto a vehicle and unloading at a dump. But successful solid waste management is rarely achieved without thought, effort and learning from mistakes. Solid waste management is much more than a technological issue -- it usually involves managing a large workforce and working closely with the public. Waste generation should be avoided as far as technically possible and economically acceptable, and waste must be recycled unless this is economically not feasible. Low waste technologies deserve priority over customary waste disposal.
According to Chittagong City Corporation source, the total generation of solid waste from all possible sources (industries, markets, clinics and hospital, households and travellers) is 1069 tons per day. It is mentionable that the amount of solid waste produced from industries and clinics added are negligible. A study was conducted from September 2004 to June 2005 to identify the most potential source and composition of biodegradable solid waste generated in the Chittagong metropolitan area, without which any energy recovery plan from solid waste tends to be trivial. The composition of the domestic source along with their sub-sources (done by systematic sampling) and physical and chemical properties were studied. Pertinent domestic source was found as the most potential (75.75%) biodegradable solid waste, which is a very good sign for its composting.
Still there is no proper master plan for solid waste management in Bangladesh. Solid waste management is ignored a lot. What happens in the city corporations are just raw dumping of waste collected from all sites in a comparatively low value low land ignoring all the environmental impacts from it. Though some small initiatives are taken but these are insufficient and are not being implemented in proper way. All of these projects and tasks should be coordinated and brought under one master plan.
There are many factors that vary from place to place and that must be considered in the design of a solid waste management system. Amongst them are:

• The waste itself: The waste contains large amounts of moisture because of the high usage of fresh fruit and vegetables and due to the high proportion of sand particles it become very dense. The combination of the extra weight, the abrasiveness of the sand and the corrosiveness caused by the water content, can cause very rapid deterioration of equipment used for transportation and disposal.
• Access to waste collection points: Many sources of waste might only be reached by roads or alleys which may be inaccessible to certain kinds of transport because of their width, slope, congestion or surface.
• Public awareness and attitude: This can effect the readiness to carry waste to a shared container, the willingness to accept the proximity of a shared container, the willingness to segregate waste to assist recycling, the frequency at which wastes should be collected, the amount of litter and animal excreta that are left on the street, the willingness to pay for waste management services etc.
• Selection of equipment: The types of vehicles and chassis that are already widely used and for which spare parts and maintenance expertise are available should influence the selection of waste collection vehicles. Institutional issues include the current and intended legislation and the extent to which it is enforced. The policy of government regarding the role of the private sector (formal and informal) should also be taken into account.

In Chittagong Metropolitan area previously there was no recycling process for the huge amount of solid waste produced but recently one recycling plant has been installed in Halisahar dumping site to produce fuel wood charcoal from freshly dumped wastes. Collecting and processing secondary materials, manufacturing recycled-content products, and then purchasing recycled products creates a circle or loop that ensures the overall success and value of recycling.
Considering the nature of the waste, its generation rates, density, composition, moisture content, size, distribution of waste materials, pH level, climatic and geographical situation to recover and recycle acceptable biodegradable materials from agricultural, municipal, institutional, commercial and industrial organic wastes in an environmentally acceptable and cost effective manner, and to produce a marketable end product, we can suggest composting as the recycling procedure for the solid waste management. Composting has the following benefits:
Conversion of a reusable waste resource to a stable and useful product as a soil amendment and mulch medium; reduction of the pollution potential of organic waste; considerable reduction in organic waste volume and weight enabling more economic handling and utilisation; destruction of various nuisance insect pests; elimination of most pathogenic organisms, rendering a pasteurized compost product; and destruction of the viability of plant seeds, particularly weed and other obnoxious plants.

Mohammad Asrafur Rahman is with the Institute of Forestry and Environmental Sciences, Chittagong University.