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Es 314 314 EnvironmentAl EnvironmentAl engineering engineering



substances or objects which are disposed of or are intended to be disposed of or are required to be disposed of by the provisions of the law

kinds of wastes
Solid waste- domestic, commercial and
industrial wastes especially common as codisposal of wastes

liquid waste- wastes in liquid form

Classification of Wastes according to their Properties



Classification of Wastes according to their Effects on Human Health and the Environment

Hazardous wastes
Substances unsafe to use commercially, industrially, agriculturally, or economically that are shipped, transported to or brought from the country of origin for dumping or disposal in, or in transit through, any part of the territory.


hazardous-waste management
It is the collection, treatment, and disposal of waste material that, when improperly handled, can cause substantial harm to human health and safety or to the environment.

Hazardous waste
may be as any waste or combination of wastes that poses substantial danger to human beings, plants and animals.

Characteristics of a Hazardous Waste:


Corrosive Reactive Toxic Radioactive

Ignitable wastes are capable of causing or intensifying a fire during routine handling.

A waste is characteristic for ignitability if it has any one of the following properties:
a liquid with a flash point less than 140 0F (60 0C);
a solid, capable under standard temperature and pressure, of causing fire through friction, absorption of moisture, or spontaneous chemical changes, and when ignited, burns vigorously and persistently; an ignitable compressed gas; or, an oxidizer.

Corrosive wastes include highly acidic or highly alkaline chemicals and those that are capable of corroding metal.

A waste has the characteristic of corrosivity if it has one of the following properties:
an aqueous waste with pH 2 or less, or pH 12.5 or greater; or, a liquid that corrodes steel at a rate greater than 6.35mm (0.25 inches) per year.

Reactive waste is synonymous with unstable water. Due to its extreme rate of reaction, an unstable waste, can create an explosive condition at any stage of the management cycle of transport, storage, treatment and disposal.

A waste has the characteristic of reactivity if it:

is normally unstable and readily undergoes violent change without detonating; reacts violently with water; forms potentially explosive mixtures with water; mixes with water to generates toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment;

is a cyanide or sulfide bearing waste which, when exposed to pH conditions between 2 and 12.5, can generate toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment; is capable of detonation or explosive reaction if subjected to a strong initiating source or heated under confinement; is readily capable of detonation or explosive; or, is a forbidden explosive or a Class A or Class B explosive.

A toxic substance is a poisonous substance; it is hazardous.

Toxicity is determined by the Toxicity Characteristic Leachate Procedure (TCLP), a laboratory test that measures the concentration of the toxic material that could leach into ground water if improperly managed.

is defined as the spontaneous breakup of the nucleus of an atom. Due to its large nucleus , it is unstable . An unstable nucleus breaks up and the atom changes to another one lower in mass.

Two particular hazardous wastes:

Dioxins- is commonly used to refer to a family of toxic chemicals that share a similar chemical structure and induce harm through a similar mechanism. A class of chemical contaminants that are formed during combustion processes such as waste incineration, forest fires, and backyard trash burning, as well as during some industrial processes such as paper pulp bleaching and herbicide manufacturing. The most toxic chemical in the class is 2,3,7,8tetrachlorodibenzo-para-dioxin (TCDD). The highest environmental concentrations of dioxin are usually found in soil and sediment, with much lower levels found in air and water.

polychlorinated biphenyl (PCB) is any of the 209

configurations of organochlorides with 2 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings. The chemical formula for a PCB is C12H10-xClx. 130 of the 209 different PCB arrangements and orientations are used commercially.

PCBs were widely used as dielectric and coolant fluids, for example in transformers, capacitors, and electric motors. Due to PCBs' toxicity and classification as a persistent organic pollutant, PCB production was banned by the United States Congress in 1979 and by the Stockholm Convention on Persistent Organic Pollutants in 2001. Concerns about the toxicity of PCBs are largely based on compounds within this group that share a structural similarity and toxic mode of action with dioxin. Toxic effects such as endocrine disruption and neurotoxicity are also associated with other compounds within the group.


of Waste
Households Commerce and Industries



Health care facilities

Mines and mineral processing cites

Listed Hazardous Waste:

The F-list (non-specific source wastes).
This list identifies wastes from common manufacturing and industrial processes, such as solvents that have been used in cleaning or degreasing operations. Because the processes producing these wastes can occur in different sectors of industry, the F-listed wastes are known as wastes from non-specific sources.

The K-list (source-specific wastes).

This list includes certain wastes from specific industries, such as petroleum refining or pesticide manufacturing. Certain sludges and wastewaters from treatment and production processes in these industries are examples of source-specific wastes.

The P-list and the U-list

(discarded commercial chemical products).

These lists include specific commercial chemical products in an unused form. Some pesticides and some pharmaceutical products become hazardous waste when discarded.

The M-listed Wastes

(discarded mercury-containing products). This list includes certain wastes known to contain mercury, such as fluorescent lamps, mercury switches and the products that house these switches, and mercury-containing novelties.

Effects of Waste

Green House Gases are accumulating in Earths atmosphere as a result of human activities, causing global mean surface air temperature and subsurface ocean temperature to rise.
Rising global temperatures are expected to raise sea levels and change precipitation and other local climate conditions. Changing regional climates could alter forests, crop yields, and water supplies. This could also affect human health, animals, and many types of ecosystems.

Deserts might expand into existing rangelands, and features of some of our national parks might be permanently altered.

Some countries are expected to become warmer,

although sulfates might limit warming in some areas.
Scientists are unable to determine which parts of those countries will become wetter or drier, but there is likely to be an overall trend toward increased precipitation and evaporation, more intense rainstorms, and drier soils. Whether rainfall increases or decreases cannot be reliably projected for specific areas.

Three categories of effects from substances of hazardous waste:

a. A carcinogenic effect is an increase in an individual's risk of contracting cancer. b. A mutagenic effect is a permanent change in the genetic material (DNA), which may be passed along to later generations.
c. A teratogenic effect is an increased risk that a developing embryo will have physical defects.

Effects of Hazardous Wastes to Human Health

Birth defects and reproductive disorders

Respiratory Conditions (e.g. Asthma) Heart Diseases (e.g. Congenital Heart Disease)

Hazardous wastes are acquired by the body through the following:

Inhalation - we can breathe vapors from hazardous liquids or even from contaminated water while taking a shower.

Ingestion - we can eat fish, fruits and vegetables, or meat that has been contaminated through exposure to hazardous substances. Also, small children often eat soil or household materials that may be contaminated, such as paint chips containing lead. Probably the most common type of exposure is drinking contaminated water.
Dermal exposure - a substance can come into direct contact with and be absorbed by our skin.

Treatment Methods on Handling Toxic and Hazardous Waste

a.) Biological Treatment
Its purpose is to convert dissolved and colloidal pollutants to cell mass, water, and gases. However, many times cell growth is too small to collect by any practical method. Microorganisms create an increased demand for oxygen when they are discharged from a treatment plant to a body of water. The challenge is to gather the cells into aggregates by filtration or sedimentation.

b.) Chemical Treatment

Is a treatment technology, either employed as the sole treatment to produce or used to reduce that hazard of a particular waste prior to transport, incineration, and burial.

Techniques used in handling hazardous waste using chemical treatment: Neutralization

Solutions are neutralized to bring about an acceptable pH. An acidic solution is added with a base to neutralize it; a basic solution is added with an acid to neutralize the mixture. A waste is hazardous at a pH less than 2.00 or greater than 12.50. the final pH values should be in the range of 6.00 to 8.00 to protect natural biodata.

Oxidation-Reduction (Redox) Reactions

Oxidation is conducted under alkaline conditions to avoid the generation of cyanide gas. The process is often referred to as alkaline chlorination. An example of this reaction is the chlorine oxidation. The reaction is carried in two steps.

The 1st step is that the pH is maintained above 10 and the reaction proceeds in a matter of minute. In this step, it is taken with greater care to maintain a relatively high pH values because at lower pH there is a potential for the evolution of highly toxic hydrogen cyanide gas.

NaCN + 2NaOH + Cl2 = NaCNO + 2NaCl + H2O

The 2nd step proceeds most rapidly around a pH of 8.00. higher pH values may be selected to reduce chemical consumption in the following precipitation steps. Often the second reaction is not carried out because the CNO is considered nontoxic by current regulations.
2NaCNO + 5NaOH + 3Cl2 = 6NaCl + CO2 + N2 +NaHCO3 + 2H2O

Precipitation A process in which an insoluble product is formed called precipitate which is often settled or removed.

c.) Physical/Chemical Treatment

It is a treatment to separate hazardous waste from aqueous solution. The waste is not detoxified but only concentrated for further treatment or recovery.

Techniques used in handling hazardous waste using physical/chemical treatment: Carbon Adsorption Adsorption is a mass-transfer process in which gas vapors or chemical solutions are held to a solid by intermolecular forces. Example of adsorbents: activated carbon, molecular sieves, silica gel, activivated alumina

Distillation It is the separation of more volatile materials from less volatile ones by a process of vaporization and condensation.
Ion Exchange In this process metals and ionized organic chemicals are recovered. Ion exchange can be defined as reversible exchange of an ion on a solid phase with an ion of like charge in an aqueous phase. This method is mostly used in water treatment to remove metals present in water.

Electrodialysis An electrodialysis unit uses a membrane to selectively retain or transmit specific molecules. The membranes are thin sheets of ion-exchange resin reinforced by a synthetic fiber backing. The construction of the unit is such that anion membranes are altered with cation membranes in stacks of cells in series. An electric potential is applied across the membrane to provide the motive force for ion migration.

Reverse Osmosis
Osmosis is the spontaneous transport of a solvent from a dilute solution to a concentrated solution across an ideal semipermeable membrane that Impedes passage of the solute but allows the solvent to flow.

Solvent Extraction
Solvent extraction is also called as liquid extraction and liquidliquid extraction. Contaminants can be removed from a waste stream using liquid-liquid extraction if the wastewater is contacted with a solvent having a greater solubility for the target of contaminants than the wastewater. The contaminants will tend to migrate from wastewater into the solvent.

ways to reduce hazardous waste

Avoid the Use of Commercial Household Cleaners Use Natural Compost as Fertilizer Avoid the Use of Pesticides Use Water Based Paints

Avoid Using Toxic Drain Cleaners

Use Natural Alternatives for Floor and Metal Polish

Dispose of any Hazardous Waste Safely

Keep Insects under Control with Natural Means

The major methods of waste management are:

Recyclingthe recovery of materials from products after they have been used by consumers.

Compostingan aerobic, biological process of degradation of biodegradable organic matter.

Sewage treatmenta process of treating raw sewage to produce a non-toxic liquid effluent which is discharged to rivers or sea and a semi-solid sludge, which is used as a soil amendment on land, incinerated or disposed of in land fill. Incinerationa process of combustion designed to recover energy and reduce the volume of waste going to disposal. Landfillthe deposition of waste in a specially designated area, which in modern sites consists of a preconstructed cell lined with an impermeable layer (manmade or natural) and with controls to minimize emissions.

Let us be responsible on handling our wastes!