Primary and secondary collection

After on-site storage, the next step is collection. Primary collection is the collection of waste from the point where it is placed by the person or organisation that has produced it. These collection points could be located outside each individual household and business, communal containers serving a number of households, or waste skips taking waste from households and businesses in the surrounding area. Depending on the collection vehicle and the distance to the waste treatment/disposal site, the waste at this stage may be taken to the final disposal site or to a transfer station, as described in Section 9.4.

Primary collection can be done in many ways. Table 9.1 summarises the lower-technology options that are suitable for collecting waste from households and transporting it to a transfer station or local disposal site. These all have the benefit of being able to serve narrow streets in crowded areas.

Secondary collections are where the waste from a number of primary collections is taken from the transfer station to the final disposal site. Table 9.2 shows some options for secondary waste collection vehicles, but note that some of these are also used for primary collections in certain situations.

Table 9.1 Options for primary collection. (Cowing et al., 2014)

Vehicle Comments

Wheelbarrow

Only suitable for taking waste from households to a communal collection point. Good for narrow streets, but needs a well-maintained street surface.

Hand-cart

The additional wheels mean that this is more stable than the wheelbarrow (especially on poor road surfaces) and it is easier to move over longer distances. It can also carry a larger volume (1–2 m3).

Suitable for door-to-door collections in crowded areas and for transporting waste to communal containers at the ends of streets or to local transfer stations.

Cycle cart

Can collect up to 3 m3 and transport the waste to a communal bin or transfer station. The cart has drop-down sides to make loading and unloading easier.

It needs a reasonable road surface and is not suitable for steep hills.

Donkey cart

Similar uses to the cycle cart. It has a drop-down end and, like the cycle cart, needs reasonable road surfaces and is not suitable for steep gradients.

Tractor

A tractor has much higher costs than the above options, but can transport up to 4 m3 of waste for distances up to around 20 km to disposal sites or transfer stations.

Table 9.2 Secondary collection vehicles. (Cowing et al., 2014)

Vehicle Comments

Truck fitted with bin lifter

A robust vehicle that can travel on rough roads. Suitable for transferring or collecting communal bins from residential and commercial areas.

Note that dump trucks without bin lifters are not recommended due to need for manual loading.

Enclosed light truck

A waste collection tipper box fitted to a conventional vehicle chassis. Useful for emptying street-side litter and communal residential waste bins. Can serve narrower streets than most motorised collection vehicles but needs better roads than truck-based vehicles.

Flatbed crane truck

Useful for collecting skips from transfer stations, markets and industrial areas.

Fitted with its own crane for loading and unloading.

Compactor

The most expensive collection/transfer vehicle, costing around US$250,000. Hydraulic compaction equipment not suitable for residential waste (which already has a high density) and hydraulics need specialist maintenance.

Only suitable for collecting low-density waste in large quantities where road conditions are good.

Of little use outside major cities.

آخری ترمیم: جمعه, 22 جولائی 2016, 9:56 ص