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Waste- Definition & ClassificationAny material which is not needed by the
owner, producer or processor.
Classification• Domestic waste• Factory waste• Waste from oil factory• E-waste• Construction waste• Agricultural waste• Food processing waste• Bio-medical waste• Nuclear waste
Classification of Wastes• Solid waste- vegetable waste, kitchen waste, household
waste etc.
• E-waste- discarded electronic devices like computer, TV, music systems etc.
• Liquid waste- water used for different industries e.g. tanneries, distilleries, thermal power plants
• Plastic waste- plastic bags, bottles, buckets etc.
• Metal waste- unused metal sheet, metal scraps etc.
• Nuclear waste- unused materials from nuclear power plants
SOURCES OF SOLID WASTE
The solid waste (i.e. garbage) includes the dry refuse like street sweepings, ash, mud, decayed vegetables and fruits, grass, leaves, paper pieces, cloth pieces, etc. The following are the sources of such solid waste:
(a) Market
(b) Road Side Dustbins
(c) Residential Area
(d) Street Sweepings
(e) Cinema and Theatre Halls (f) Schools and Colleges
(g) Hospitals
COLLECTION AND REMOVAL OF SOLID WASTE
The following vehicles are employed for the removal of solid waste.
1. Rickshaw-vans6.Wheeled Baskets7.Trailors8.Trucks
DISPOSAL OF SOLID WASTEThe following are the general methods of disposal:
(a) By trenching: In this method, trenches are excavated in barren lands far away from the town The garbage is dumped into the trench and leveled properly.
(b) By land filling: In this method, the garbage is dumped in low-lying area phase by phase.
(c) By incineration: The process of burning the garbage into ash is known as incineration
(d) By pulverization: The method of grinding the garbage into powder is known as pulverization
(e) By composting: In this method, the garbage is converted to manure in a mechanical compost plant. This is a hygienic method of garbage disposal. Here, the worthless materials may be obtained as useful materials like fertilizer
(f) By disposal to sea: In coastal towns, the disposal of garbage into the sea But the garbage should be discharged into the deep sea by studying the current and wave action of the sea so that it may not return to the shore again.
Solid Waste in Pakistan• 7.2 million tonnes of hazardous waste
• One Sq km of additional landfill area every-year
• Rs 1600 crore for treatment & disposal of these wastes
• In addition to this industries discharge about 150 million tonnes of high volume low hazard waste every year, which is mostly dumped on open low lying land areas.
Growth of Solid Waste In Pakistan
• Waste is growing by leaps & bounds
• In Pakistan , population is increasing day by day from 16 caror to 18 caror.
• During the same period, municipal solid waste has grown from 3200 tonnes to 5355 tonne, an increase of 67%
• Waste collection is very low for all Pakistan cities
• Cities like Karachi, Lahore produces 2000 tonnes of waste per annum, the ever increasing waste has put pressure on hygienic condition of the cities
Waste Collection in Pakistan
• Primarily by the city municipality-No gradation of waste product e.g. bio-degradable, glasses, poly bags, paper shreds etc-Dumps these wastes to the city outskirts
• Local Talukas / Distt: (Rag pickers)-Collecting small iron pieces by magnets-Collecting glass bottles-Collecting paper for recycling
Hazardous / Toxic Waste & Dumping Site
• Industrialized countries have waste management problems
• Developed countries have strict environment regulation norms
• Most attractive option for them- to dump into developing countries
Major Polluting Industries in Pakistan
• Around 2500 tanneries discharge 24 million cu m of waste water containing high level of dissolved solids and 4,00,000 tonnes of hazardous solid waste
• Thermal power plants discharge huge waste materials
Managing WasteRecycling: Processing of a waste item into usable forms.
Benefits of recycling:-Reduce environmental degradation-Making money out of waste-Save energy that would have gone into waste handling &
product manufacture
Saving through recycling:-When Al is resmelted- considerable saving in cost-Making paper from waste saves 50% energy-Every tonne of recycled glass saves energy equivalent to
100 liters of oil
Recycling not a solution to all problems!
Recycling is not a solution to managing every kind of waste material
For many items recycling technologies are unavailable or unsafe
In some cases, cost of recycling is too high.
Solution: More Profit With Zero Waste
• Exchanging output that are considered waste
• Waste of one could be input or raw material for others
• Evolving a closed system- matter & energy circulate within
• System was not designed to be so
• The system of exchange evolved in 10 years
Problems in Dealing With Solid Waste
• Education & voluntary compliance
• Collection of waste
• Technological interventions
• Institutions & regulatory framework
• Absence of mandatory standards for waste reduction
• Market action for waste reduction
Source: The Energy & Resources Institute