Solid & Hazardous Waste Management Lecture 3

Waste Classification

• Waste is any material that is not needed by the owner, producer, or processor.
• Types of waste: domestic, factory/industrial, oil factory, e-waste, construction, agricultural, food processing, bio-medical, and 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 like 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).
• 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: residential, commercial, institutional, industrial, construction, and demolition activities.

Municipal Solid Waste Management

• RA 9003: Ecological Solid Waste Management Act of 2000.
• Strategies: source reduction (waste prevention), recycling, composting.

Waste Management Hierarchy

• Source reduction (waste prevention).
• Recycling: recovery of useful materials, such as paper, glass, plastic, and metals, from the trash to use to make new products.
• Composting: involves collecting organic waste, such as food scraps and yard trimmings, and storing it under conditions designed to help it break down naturally.

Disposal and Combustion of Municipal Solid Waste

• Landfills: engineered areas where waste is placed into the land, with liner systems and other safeguards to prevent polluting the groundwater.
• 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 briefly held while it is reloaded onto larger, long-distance transport vehicles for shipment to landfills or other treatment or disposal facilities.

Open Dump

• Unsanitary, draws 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 stop the escape of leachates.
• Gases produced by decomposing garbage need venting.
• Avoid: swampy area/flood plains/coastal areas, fractures or porous rocks, high water table.
• Prefer: clay layers, heads of gullies.

Monitoring of Sanitary Landfills

• 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: waste to energy.

Hazardous Waste

• Hazardous waste is a waste with properties that make it dangerous or potentially harmful to human health or the environment.
• Properties: ignitability, corrosivity, reactivity, toxicity.
• Major types: toxic organics, heavy metals, radioactive wastes.
• Hazardous diamond and symbols: NFPA diamond, CLP, GHS.

Dealing with Hazardous Wastes

• RA 6969: Toxic Substances and Hazardous and Nuclear Wastes Control Act of 1990.
• Methods: physical (cementation, encapsulation), chemical (chem. stabilization/fixing), bioremediation, phytoremediation, plasma incineration.

Life Cycle of Waste

• Cradle to Grave.
• Sustainable: reduce, reuse, recycle, recover, dispose.