Lecture 3: Solid & Hazardous Waste Management

Waste Classification

• Waste is any material not needed by the owner, producer, or processor
• Classification of waste includes: • Domestic waste • Factory/Industrial waste • Waste from oil factory • E-waste • Construction waste • Agricultural waste • Food processing waste • Bio-medical waste • Nuclear waste

Composition of Classified Wastes

• Solid waste: vegetable waste, kitchen waste, household waste, etc.
• E-waste: discarded electronic devices like computers, TVs, music systems, etc.
• Liquid waste: water used for different industries (e.g., tanneries, distilleries, dairy industries, thermal power plants)
• Plastic waste: plastic bags, bottles, buckets/containers, etc.
• Metal waste: unused metal sheets, metal scraps, etc.
• Nuclear waste: unused materials from nuclear power plants

Solid Waste

• Any garbage or refuse (Municipal Solid Waste)
• Includes: • Garbage – wet discard or kitchen waste (rubbish) • Trash – dry discard (e.g., waste paper, dust, etc.) • Other terms: refuse, litter

Municipal Solid Waste Sources

• Sources include: • Residential areas • Commercial areas • Industrial areas • Institutional areas • Construction and demolition activities

Municipal Solid Waste Generation

• In Metro Manila, 0.50 kg/capita/day of solid waste is generated
• With a population of ~12M, this translates to 6000 tons of SW/day
• The city relies only on garbage collection; no composting, no burning

Municipal Solid Waste Management

• RA 9003: Ecological Solid Waste Management Act of 2000
• Strategies include: • Reduction or waste prevention • Recycling • Composting

Waste Reduction

• Designing products to reduce waste generation
• Making the resulting waste less toxic

Recycling

• Recovery of useful materials (e.g., paper, glass, plastic, metals) from trash
• Using these materials to make new products, reducing the need for virgin raw materials

Composting

• Collecting organic waste (e.g., food scraps, yard trimmings) and storing it under conditions that help it break down naturally
• The resulting compost can be used as a natural fertilizer

Disposal and Combustion of Municipal Solid Waste

• Landfills: • Engineered areas where waste is placed into the land • Liner systems and safeguards to prevent groundwater pollution
• Energy Recovery from Waste: • Conversion of non-recyclable waste materials into useable heat, electricity, or fuel
• Transfer Stations: • Facilities where municipal solid waste is unloaded from collection vehicles and reloaded onto larger transport vehicles for shipment to landfills or other treatment or disposal facilities

Open Dump

• Unsanitary and attracts pests and vermin
• Harmful runoff and leachates, toxic gases
• Still accounts for half of solid waste

Sanitary Landfill

• Characteristics: • Layer of compacted trash covered with a layer of earth once a day and a thicker layer when the site is full • Impermeable barriers to prevent leachate escape • Gases produced by decomposing garbage need venting
• Avoid: • Swampy areas/flood plains/coastal areas • Fractures or porous rocks • High water table
• Prefer: • Clay layers • Heads of gullies

Monitoring of Sanitary Landfills

• Parameters to monitor include: • Gases: Methane, Ammonia, Hydrogen sulfide • Heavy Metals: Lead, Chromium in soil • Soluble substances: chloride, nitrate, sulfate • Surface run-offs • Vegetation: may pick up toxic substances • Plant residue in soil • Paper/plastics, etc. – blown by the wind

Incineration

• Solves space problem but: • Produces toxic gases like dioxins, Cl, HCl, HCN, SO2 • High-temperature furnaces break down hazardous compounds, but are expensive • Heat generated can be recovered: % of waste burnt

Hazardous Waste

• Hazardous waste is waste with properties that make it dangerous or potentially harmful to human health or the environment
• Properties of hazardous waste include: • Ignitability • Corrosivity • Reactivity • Toxicity
• Major types of hazardous waste: • Toxic Organics • Heavy Metals • Radioactive wastes

Dealing with Hazardous Wastes

• RA 6969: Toxic Substances and Hazardous and Nuclear Wastes Control Act of 1990
• Strategies for dealing with hazardous waste include: • Detoxifying and removing wastes • Physical methods – cementation, encapsulation • Chemical methods – chemical stabilization or fixing • Bioremediation • Phytoremediation • Plasma incineration

This quiz covers the classification and composition of different types of waste, including domestic, industrial, and hazardous waste. Topics include waste management and environmental impact.