Waste of activities and processes or its ashes which retain the properties of hazardous substances and have no subsequent original or alternative uses.
US EPA Waste catalogue
According to US Environmental Protection Agency (US EPA) legislation, four main characteristics have been considered for classification of hazardous waste:
European Waste Catalogue
The European Waste Catalogue (EWC) established in 1993 includes 645 waste types. Hazardous Waste List (HWL) established in 1994 is a subset of the EWC and consists of 236 of the 645 EWC waste types that were considered to be hazardous at the time that list was agreed. Characteristics of the wastes are:
Eco - Toxic
Liberates toxic gases by reaction with acid or water.
The Basel Convention List
The Basel convention established the following Hazardous Wastes characteristics:
Waste liable to spontaneous combustion
Waste emits flammable gases by reaction with water
Liberates toxic gas in contact with water
Toxic (delayed or chronic)
Egyptian classification of hazardous waste includes five lists and four distinguishable characteristics:
a. Hazardous Waste Lists
Certain classes of chemical wastes are specifically listed as being hazardous wastes have been defined. These wastes are known as "Listed Hazardous Wastes". Common listed wastes include:
S-Listed Wastes (Special)
Gas cylinder or Aerosol cans waste
Empty container waste
Wastes generated during a non- specific industrial process. Solvents such as paint thinners with Xylene, Toluene or Acetone and carburetor cleaner, sludges from electroplating, wastewater treatment sludges, leachate, spent ion exchangers and activated glass are included in this list.
Wastes generated from specific industrial processes such as:
Pigments and paints
Petrochemicals and pyrolytics
Iron and steel
Non- Ferro metallurgical and metal works
Metal surface treatment (etching, staining, polishing, galvanizing, cleaning, degreasing)
Ink formulation and printing
Pharmaceuticals and cosmetics
Pulp & paper
Leather and fur
Production or use of solvents
Removal of coatings
Coating paints, lacquers, varnishes and plastics
Glues, cements, adhesive latex and resins
Production or use of materials made with silicones
Cleaning, emptying and maintenance of tanks
Cleaning of barrels containing chemical substances
Water and air purification
Incineration, distillation and concentration treatment
Maintenance and repair work of vehicles.
Wastes that contain acutely hazardous (extremely toxic), off-specification materials as well as container residues and spill residues of these materials.
Wastes that contain unused toxic hazardous, off-specification materials as well as container residues and spill residues of these materials.
b. Criteria for Listing Hazardous Waste
Exhibits any of the characteristics of hazardous waste identified.
Has been found to be fatal to humans in low doses or, in the absence of data on human toxicity, it has been shown to have an oral LD50 toxicity measured in rats of less than 50 milligrams per kilogram. An inhalation LC50 toxicity measured in rats of less than 2 milligrams per liter, or a dermal LD50 toxicity measured in rabbits of less than 200 milligrams per kilogram or is otherwise capable of causing or significantly contributing to an increase in serious irreversible, or incapacitating reversible, illness (Acute toxicity, P-Listed Waste).
Contains any of the toxic constituents listed in U-listed waste and the waste is capable of posing a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported or disposed of, or otherwise managed depending on the following factors:
The nature of the toxicity presented by the constituent.
The concentrations of the constituents in the waste.
The potential of the constituent or any toxic degradation product of the constituent to migrate from the waste into the environment under the types of improper management.
The persistence of the constituent or any toxic degradation product of the constituent.
The potential for the constituent or any toxic degradation product of the constituent to degrade into non- harmful constituents and the rate of degradation.
The degree to which the constituent or any degradation product of the constituent bio-accumulates in ecosystems.
The plausible types of improper management to which the waste could be subjected.
The quantities of the waste generated at individual generation sites or on a regional or statewide basis.
The nature and severity of the human health and environmental damages that has occurred as a result of the improper management of wastes containing the constituent.
Actions taken by other governmental agencies or regulatory programs based on the health or environmental hazard posed by the waste or waste constituent.
Hazardous wastes that have been listed in accordance with the criterion in (2) are designated as acute hazardous (extremely toxic) wastes (List P) and wastes that have been listed in accordance with the criterion in (3) are designated as toxic wastes (list U).
c. Screening tests for hazardous waste characterization
The sample is slowly heated (in a closed cup tester) at a constant rate with continual stirring. A small flame is directed into the cup and the flash point is measured. It is the lowest temperature at which application of the test flame ignites the vapor above the sample. Wastes that have a flash point <60° C are ignitable (flammable).
The test material is formed into an unbroken strip or powder train 250 mm in length and 1 cm cross section. An ignition source is applied to one end of the test material to determine the burning rate. Waste that have a rate of burning more than 2.2 mm / sec. or burn time less than 45 sec. for 100 mm are considered to have a positive result for ignitability.
A circular specimen of SAE 1020 steel of about 375 cm diameter and 0.32 cm thickness is allowed to interact with the waste solution at 55° C for 24 hours. The waste has corrosive characteristics if the rate of corrosion is more than 6.35 mm per year.
Aqueous waste with PH less than 2 and more than 12.5 are corrosive. Similarly, solids or non- liquid waste when mixed with an equivalent weight of water and shaken well produces a solution having a pH less than 2 and more than 12.5
Solutions of corrosive hazardous waste cause visible necrosis of rabbit skin within 4 hours of continuous contact.
Reactive waste is capable for detonation or explosive decomposition if heated or allowed to react with water with potential explosion or violent generation of gases or vapor.
Reactive wastes upon acidification to pH ~ 2 release H2S (>250 ppm) or HCN (>500 ppm).
Reactive wastes or their aqueous extract upon reaction with 10% KI release iodine that gives violet color with starch.
Toxicity Characteristics Leaching Procedure (TCLP) is used. A 250g (dry weight) of finely ground solid waste or liquid waste is placed in 1.5 L flask and treated with one liter of acetic acid/ acetate buffer of pH 3-5. At the end of 18 of hours stirring, the solution is filtered through a 0.45 mm filter, the supernatant is collected and analyzed for metals, herbicides, pesticides, volatile organic and semi volatile organics using the standard methods of analysis.
Toxicity of rats by measuring (lethal dose) LD50, or lethal concentration (LC5) (i.e. 50% mortality within 14 days or 4 hours) may be used.