SOLID WASTE - INTRODUCTIONDefinition: Any moveable solid material that is perceived to be of no further use and is permanently discarded.

Source of solid waste: domestic, office / commerce, agricultural, mining, industrial, energy production.

Solid waste produced from domestic and business are called municipal wastes, non-hazardous and only require normal methods of disposal. e.g. vegetables, plastic, wood, glass, paper, etc.

Guess the highest percentage of solid waste comes from which sources?

Methods of treatmentFactories, e.g palm oil mill

Methods of treatment

HAZARDOUS WASTE - INTRODUCTIONDefinition: Hazardous waste means solids, sludge, liquids and containerized gasses other than radioactive and infectious wastes which by reason of their chemical activity or toxic, explosive, corrosive or other characteristics cause danger or likely will cause danger to healthy or environment, whether alone or when coming into contact with other waste.

e.g Lead, Arsenic, Mercury, Mercury Metallic, Benzene, Polychlorinated biphenyls (PCBs), Cadmium, Benzo (a) pyrene, Chloroform, Benzo (b) fluoranthene, Aroclor 1260, Aroclor 1254, Chromium (+6) etc.

HAZARDOUS WASTE - CLASSIFICATIONCan be determined in either 2 ways:

Laboratory tests on the list of specific wastes - having the potential to exhibit hazardous characteristics.

Based on laboratory test, a hazardous waste is having any of the following characteristic.Corrosivity (highly acidic or alkaline, i.e pH 2 or 12.5)-Ignitability (easily ignited and thus posing a fire hazard during routine management)-Reactivity (capable of potentially harmful, sudden such reactions such as explosion)Toxicity (capable of releasing specified substances to water in significant concentrations)

HAZARDOUS WASTE - ORIGINDeliberated addition to soil, water or air by humans.Evaporation or wind erosion from waste dumps into the atmosphere.Leaching from waste dumps into groundwater streams of water.Leakage such as from underground storage tanks or pipelines.Evaluation and subsequent deposition by accidents such as fire or explosion.Release from improperly operated waste treatment, storage and disposal facilities.

HAZARDOUS WASTE - PROPERTIESPhysical-chemical properties of hazardous waste,

Vapour pressure - Varies with T and P.Solubility - the degree to which one substance (solute) will dissolve into another solventDiffusion coefficient - define as the movement of a contaminant under the influence of a concentration gradient.Bioconcentration factor (BCF) - amount of a chemical that is likely to accumulate in aquatic organismsSorption - process by which a component (sorbate or contaminant) moves from one phase to another phase across some boundary.

HAZARDOUS WASTE - PROPERTIESMost of the hazardous chemicals are classified as organic chemical. Organic chemicals can be divided to:

Volatile organic compounds (VOC): high vapour pressure which allow them to evaporate quickly, high solubility and low BCF

Semi-volatile organic compounds: typically subcategorized as base/neutral and acid extractable.Base/neutral extractable are PAHs, nitrosamines, ether, having low to moderate vapour pressureAcid extractable are usually phenolic compunds, having high BCF

HAZARDOUS WASTE - CONTAMINANT RELEASEThe release of contaminants from the waste site can occur in one or all of the three phases:

Liquid release contaminated runoff, direct aqueous discharges to surface water, leachate to ground water

Air emission stack emissions including gaseous and particulates, volatile emissions from lagoons.

Solid suspended solids in water

EFFECT OF HAZARDOUS WASTE There are 3 exposure routes by which environmental contaminants can enter body

Inhalation (respiratory tract) Ingestion (gastrointestinal tract) Dermal contact (skin)

EFFECT OF HAZARDOUS WASTE The immediate and long term effects are:

Sensitisation - skin contact with a chemicalNeurotoxicity - damage to the central nervous system Teratogenecity - damage to the embryo and fetus leading to birth defectMutagenicity - damage that result in change to the DNA structure in genesCarcinogenicity - the development of malignant tumors and neoplasms (new growth)

TREATMENT OF HAZARDOUS WASTE Treatment and disposal of hazardous waste,

1.Neutralisation2.Oxidation3.Reduction4.Reverse Osmosis5.Ion-Exchange6.Carbon adsorption7.Recovery of acids8.Phenol destruction9.Evaporation stripper

For wastewater which contain suspended solids, physical separation process e.g. filtration

TREATMENT OF HAZARDOUS WASTE

ENVIRONMENTAL REGULATION There are 3 specific regulation to control toxic and hazardous waste under EQA 1974.

Environmental Quality (Scheduled Waste) Regulations, 1989Environmental Quality (Prescribed Premises) (Scheduled Waste Treatment and Disposal Facilities) Order, 1989Environmental Quality (Prescribed Premises) (Scheduled Waste Treatment and Disposal Facilities) Regulations, 1989