Monday, October 3, 2011

Waste Separation at Home - Key to Sustainable Solid Waste Recycling

By Hammed Taiwo 

The question that frequently comes to my mind is that how far can a newly established recycling project be sustained in Nigeria? First and foremost, the success of solid wastes management through their recycling into useful products and, in fact, any waste management strategy depends on how well the mixed solid wastes are separated into different components. In Nigeria, like other developing countries, waste separation at home or point of generation is considered as a messy exercise. Almost everybody wants to move waste from his or her sight as quick and as cheap as possible, immediately after their generation. Meanwhile, storing wastes together make recycling operations a very tedious exercise. It reduces the productivity and increases cost of production at waste recycling plant. It also reduces the quality of recycled products. For instance, organic fraction of mixed wastes stored together decomposes with foul odour that attracts flies and pests of economic importance.

Apart from waste separation into major components like glass, rubber, paper etcetera at points of generation, another challenge faced by waste recyclers is the complex nature of some components like plastics, nylon and metal that involves post separation at site. Nylon and plastics in a waste stream are of different kinds, based on their chemical make-up. They can be LDPE- low density poly-ethelyne, HDPE- high density poly-ethelyne, PP raffia, PP stripe and so on. Just like nylon and plastics, metal scraps also include ferrous and non-ferrous metal that cannot be recycled together because of their different melting points. This secondary separation at waste recycling site requires skill and time, making the recycling process labour intensive with attendant cost implication. Perhaps, poor separation of recyclable materials affects the quality of recycled products and reduces their marketability.

Successful recycling requires that recyclables can compete well with virgin materials in quality as well as price. The price of refined or recycled materials is determined by the over all cost of collection activities. The quality is influenced by the way collection activities including sorting are performed. However wastes are not normally collected in cost-effective and environmentally sound manner in this country. Research has shown that waste collection and segregation into different components account for largest share of total costs of solid wastes recycling. The practice that is common in the country up till now is that governments collect commingle wastes and dispose them at landfills that are not sanitary and properly underlined for leachate control. This practice is neither sustainable nor environmental friendly. It does not give room for resource conservation through waste recycling. In many cases, scavengers, poor and jobless people from low socio-economic stratum, parade such landfills to salvage recyclable materials like plastics, bobbles and metal scraps, at the extent of their health and well being.

Recyclable fractions of mixed wastes can be segregated and transported into recycling centre by different methods. Most of these methods are not practicable and cost-effective in many countries of the world. In the first method, waste segregation is carried out at homes during the storage processes and the sorted wastes are collected directly from households. In another situation, mixed wastes are collected from households and transferred into a designated sorting centre where people are employed to carryout the separation. The sorted recyclable components are then transferred into recycling facility for processing while the non-recyclables are transferred into landfills. Anyhow, the first scheme is cheaper than the second. It is also possible for waste producers to bring recyclable wastes directly to recycling facility without being charged for waste disposal service. In some cases, such wastes are sold to the facility at a predetermined cost. Independent buyers may be involved in both collection of waste and recovery of materials. The buyers often pay the generators of materials, either in cash or by barter. The buyers popularly called 'paaro' (means 'exchange' in Yoruba language) exchange plastic pails for fairly used cloth, jewelries and shoe materials. Waste sorting can also be done by waste collection team who quickly remove valuable materials from waste stream on their way to land fill. This can rather not be well controlled.

Modes of waste collection and transportation also have great impact on waste segregation and recycling operation. Co-collection occurs when all separated fractions are collected from households in the same vehicle. Segregated collection occurs when different fractions are collected in different vehicles. Co-collection can also be performed in two ways. A multi-compartment vehicle can be used to transport sorted wastes at the same time. Each component of separated wastes can also be bagged at household level and transported in the single compartment vehicle. The third possibility is to use alternating schedules whereby one component of sorted wastes is collected today and another component the following day. It is not feasible to have one vehicle for one waste component in Nigeria as well as many developing countries because of their economic situations. The third possibility is not cost-benefit either.

Finally, mixed waste collection directly from communities by Nigerian government is seen to be very easier but this result into separation complexity at recycling facilities. On the other hand, transportation of sorted wastes from households makes collection and transportation complexity but ensures easier operation at reduced costs at recycling facilities. It is right time determine the best segregation and transportation scheme for the country. The methods that favour waste recycling and material recovery should be considered as permanent solution to persistent waste management problems in the country. The schemes whereby wastes are segregated at household level; bagged and transported in a single compartment vehicle need to be encouraged. Alternatively, Government should also consider intermediate sorting center where mixed wastes will be sorted before final transportation into recycling facilities. This offers a big advantage in terms of income generation for the jobless and teaming population of unemployed youths.

1 comment:

  1. Thanks again for visiting to my blog today at , and I really appreciate it.

    I found many ads here from Google Adsense. I have never get paid or payment from the Google. My website is good page rank (PR) 5, but the language is not supported by the google.

    Greetings from Indonesia