Lecture 3: Solid & Hazardous Waste Management

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

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

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

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

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

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

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

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

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

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 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

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