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Thursday, December 25, 2008

Kerbside collection,Waste management and resource recovery,green bins

Kerbside collection (UK, Australia and other former colonies) or curbside recycling (elsewhere) is a service provided to households, typically in urban and suburban areas, of removing household waste. It is usually accomplished by personnel using purpose built vehicles to pick up household waste in containers acceptable to or prescribed by the municipality.

History

Prior to the twentieth century the amount of waste generated by a household was relatively small. Household wastes were often simply thrown out the window, buried in the garden or deposited in outhouses (see more at urban archaeology). When human concentrations became more dense, waste collectors, called nightmen or gong farmers were hired to collect the night soil, performing their duties only at night (hence the name). Meanwhile, as cities developed, disposing of refuse became a problem. In 1830’s Manhattan, for example, thousands of hogs were permitted to roam the streets and eat garbage. A small industry developed as “swill children” collected kitchen refuse to sell for pig feed, and the rag and bone man traded goods for bones (used for glue) and rags (essential for paper prior to the invention of wood pulping).

As sanitation engineering came to be practiced beginning in the mid-nineteenth century and human waste was conveyed from the home in pipes, the gong farmer was replaced by the trash collector as there remained growing amounts of household refuse, including coal ash which was a primary form of home heating in the nineteenth century.

By the early part of the twentieth century economies prospered and manufacturers began to introduce package goods. As refuse began to clog city streets, municipalities began to pass anti-dumping ordinances and introduce kerbside collection. Residents used a variety of refuse containers to facilitate kerbside collection but the main type was the metal garbage can. It was not until the late 1960’s that the green bin bag was introduced by Glad. Later, as waste management practices were introduced with the aim of reducing landfill impacts, a range of container types came to be introduced to facilitate the proper diversion of the waste stream. Such containers include blue boxes, green bins, and Wheelie bins or MGBs.

Over time, waste collection vehicles gradually increased in size from the hand pushed English dust cart, a name by which these vehicles are still referred, to large compactor trucks.

Waste management and resource recovery

Kerbside collection is today often referred to as a strategy of local authorities to collect recyclable items from the consumer. Kerbside collection is considered a low risk strategy to reduce waste volumes and increase recycling rates. Materials are typically collected in large bins, colored bags, or small open plastic tubs, specifically designated for content.

Recyclable materials that may be separately collected from municipal waste include:

Biodegradable waste component

* Green waste
* Kitchen waste
* Paper

Other recyclable components

* Plastics (#1 PET, #2 HDPE natural and colored, #3 PVC narrow-necked containers, #4 LDPE, #5 PP, #7 other mixed resin plastics)
* Glass
* Metals (ferrous and non-ferrous)
* Co-mingled recyclables- can be sorted by a clean materials recovery facility

Kerbside collection of recyclable resources is aimed to recover purer waste streams with higher market value than by other collection methods. If the household incorrectly separates the recyclable elements they load may have to be put to landfill if it is deemed to be contaminated.

Kerbside collection and household recycling schemes are also being used as tools by local authorities to increase the public's awareness of their waste production.

Kerbside collection is commonly considered to be completely environmentally friendly. This may not necessarily be the case as it leads to an increased number of waste collection vehicles on the road, contributing to global warming through exhaust emissions.[citation needed]

New and emerging waste treatment technologies such as mechanical biological treatment may offer an alternative to kerbside collection through automated separation of waste in recycling factories.

Kerbside collection by country

Canada

Halifax Regional Municipality in Nova Scotia, Canada, with a population of about 375,000, has one of the most complex kerbside collection programs in North America. Based on the green cart, it requires residents to self-sort refuse and place different types at the kerb on alternating weeks. As shown in the photo at left, Week 1 would see the green cart and optional orange bags used for kitchen waste and other organics such as yard waste. Week 2 would permit non-recoverable waste in garbage bags or cans. Blue bags are used for paper, plastic and metal containers. Together with used grocery bags containing newspapers, they may be placed on the kerb either week. In summer, the green cart is emptied weekly due to the prevalence of flies. HRM has achieved a diversion rate of approximately 60 percent by this method.

Canada uses "green bins" for kerbside recycling

New Zealand

By 1996 the New Zealand cities of Auckland, Waitakere, North Shore and Lower Hutt had kerbside recycling bins available. In New Plymouth, Wanganui and Upper Hutt recyclable material was collected if placed in suitable bags. By 2007 73% of New Zealanders had access to kerbside recycling.

Kerbside collection of organic waste is carried out by the Mackenzie District Council and the Timaru District Council. Other councils are carrying out trials.

United Kingdom

In the United Kingdom, the Household Waste Recycling Act (2003) will require local authorities to provide every household with a separate collection of at least two types of recyclable materials by 2010.

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