Hazardous wASTEMANAGEMENT

Hazardous waste is waste that poses substantial or potential threats to public health or the environment

WHAT IS HAZARDOUS WASTE?

Toxic wastes are poisons, even in very small or trace amounts. They may have acute effects, causing death or violent illness, or they may have chronic effects, slowly causing irreparable harm

EFFECTS CAUSE BY HAZARDOUS WASTE Hazardous wastes can take the form of solids, liquids, sludges,

or contained gases, and they are generated primarily by chemical production, manufacturing, and other industrial activities. They may cause damage during inadequate storage, transportation, treatment, or disposal operations. Improper hazardous-waste storage or disposal frequently contaminates surface and groundwater supplieS.

Hazardous wastes are classified on the basis of their biological, chemical, and physical properties. These properties generate materials that are either toxic, reactive, ignitable, corrosive, infectious, or radioactive.

HAZARDOUS WASTE CHARACTERISTICS

Toxic wastes are poisons, even in very small or trace amounts. They may have acute effects, causing death or violent illness, or they may have chronic effects, slowly causing irreparable harm. Some are carcinogenic, causing cancer after many years of exposure. Others are mutagenic, causing major biological changes in the offspring of exposed humans and wildlife.

TOXIC WASTES

Reactive wastes are chemically unstable and react violently with air or water. They cause explosions or form toxic vapours. Ignitable wastes burn at relatively low temperatures and may cause an immediate fire hazard. Corrosive wastes include strong acidic or alkaline substances. They destroy solid material and living tissue upon contact, by chemical reaction.

REACTIVE WASTE

. Radioactive wastes emit ionizing energy that can harm living organisms. Because some radioactive materials can persist in the environment for many thousands of years before fully decaying, there is much concern over the control of these wastes. However, the handling and disposal of radioactive material is not a responsibility of local municipal government. Because of the scope and complexity of the problem, the management of radioactive waste—particularly nuclear fission waste—is usually considered an engineering task separate from other forms of hazardous-waste management and is discussed in the article nuclear reactor.

. Radioactive wastes

Paints and solventsAutomotive wastes (used motor oil, antifreeze, etc.)Pesticides (insecticides, herbicides, fungicides, etc.)Mercury-containing wastes (thermometers, switches, fluorescent lighting, etc.)Electronics (computers, televisions, cell phones)Aerosols / Propane cylindersCaustics / Cleaning agentsRefrigerant-containing appliancesSome specialty Batteries (e.g. lithium, nickel cadmium, or button cell batteries)AmmunitionRadioactive waste (some home smoke detectors are classified as radioactive waste because they contain very small amounts of a radioactive isotope of americium - see:Disposing of Smoke Detectors).

Household Hazardous Waste

MANAGEMENT OF HAZARDOUS WASTE

PROCESSES

In the United States a key feature of regulations pertaining to waste transport is the “cradle-to-grave” manifest system, which monitors the journey of hazardous waste from its point of origin to the point of final disposal. The manifest system helps to eliminate the problem of midnight dumping. It also provides a means for determining the type and quantity of hazardous waste being generated, as well as the recommended emergency procedures in case of an accidental spill. A manifest is a record-keeping document that must be prepared by the generator of the hazardous waste, such as a chemical manufacturer. The generator has primary responsibility for the ultimate disposal of the waste and must give the manifest, along with the waste itself, to a licensed waste transporter. A copy of the manifest must be delivered by the transporter to the recipient of the waste at an authorized TSDF. Each time the waste changes hands, a copy of the manifest must be signed. Copies of the manifest are kept by each party involved, and additional copies are sent to appropriate environmental agencies.

The manifest system

Treatment, storage, and disposal

Hazardous waste can be treated by chemical, thermal, biological, and physical methods. Chemical methods include ion exchange, precipitation, oxidation and reduction, and neutralization. Among thermal methods is high-temperature incineration, which not only can detoxify certain organic wastes but also can destroy them. Special types of thermal equipment are used for burning waste in either solid, liquid, or sludge form. These include the fluidized-bed incinerator, multiple-hearth furnace, rotary kiln, and liquid-injection incinerator. One problem posed by hazardous-waste incineration is the potential for air pollution.Biological treatment of certain organic wastes, such as those from the petroleum industry

TREATMENT

One method used to treat technique the waste is carefully hazardous waste biologically is called landfarming. In this mixed with surface soil on a suitable tract of land. Microbes that can metabolize the waste may be added, along with nutrients. In some cases a genetically engineered species of bacteria is used. Food or forage crops are not grown on the same site. Microbes can also be used for stabilizing hazardous wastes on previously contaminated sites; in that case the process is called bioremediation.

LANDFILLING

Hazardous wastes that are not destroyed by incineration or other chemical processes need to be disposed of properly. For most such wastes, land disposal is the ultimate destination, although it is not an attractive practice, because of the Environment risk is involvedTemporary on-site waste storage facilities include open waste piles and ponds or lagoons. New waste piles must be carefully constructed over an impervious base and must comply with regulatory requirements similar to those for landfills. The piles must be protected from wind dispersion or erosion.A common type of temporary storage impoundment for hazardous liquid waste is an open pit or holding pond, called a lagoon. New lagoons must be lined with impervious clay soils and flexible membrane liners in order to protect groundwater. Leachate collection systems must be installed between the liners, and groundwater monitoring wells are required

SURFACE STORAGE AND LAND DISPOSAL

Disposal of hazardous waste in unlined pits, ponds, or lagoons poses a threat to human health and environmental quality. Many such uncontrolled disposal sites were used in the past and have been abandoned. Depending on a determination of the level of risk, it may be necessary to remediate those sites. In some cases, the risk may require emergency action. In other instances, engineering studies may be required to assess the situation thoroughly before remedial action is undertaken

Remedial action

RecyclingPortland cement

Incineration, destruction and waste-to-energy.

Final disposal of hazardous waste

Many hazardous wastes can be recycled into new products. Examples might include lead-acid batteries or electronic circuit boards. Where the heavy metals these types of ashes go through the proper treatment, they could bind to other pollutants and

convert them into easier-to-dispose solids, or they could be used as pavement filling.

Recycling

Another commonly used treatment is cement based solidification and stabilization. Cement is used because it can treat a range of hazardous wastes by improving physical characteristics and decreasing the toxicity and transmission of contaminants. The cement produced is categorized into 5 different divisions, depending on its strength and components. This process of converting sludge into cement might include the addition of pH adjustment agents, phosphates, or sulfur reagents to reduce the settling or curing time, increase the compressive strength, or reduce the leach ability of contaminants.

Portland cement

Starved air incineration is an improvement of the traditional incinerators in terms of air pollution. Using this technology, it is possible to control the combustion rate of the waste and therefore reduce the air pollutants produced in the process

• Incineration, destruction and waste-to-energy

Some hazardous waste types may be eliminated using pyrolysis in an ultra high temperature electrical arc, in inert conditions to avoid combustion. This treatment method may be preferable to high temperature incineration in some circumstances such as in the destruction of concentrated organic waste types, including PCBs, pesticides and other persistent organic pollutants

Pyrolysis

The Environmental Protection Agency has prepared a revised National Hazardous Waste Management Plan  for the Republic of Ireland covering a six-year period from the date of publication (2014-2020). This third Plan is a revision of the National Hazardous Waste Management Plan 2008 - 2012 and sets out the priorities to be pursued over the next six years and beyond to improve the management of hazardous waste, taking into account the progress made since the previous plan and the waste policy and legislative changes that have occurred since the previous plan was published.The objectives of the revised Plan are:To prevent and reduce the generation of hazardous waste by industry and society generally;To maximise the collection of hazardous waste with a view to reducing the environmental and health impacts of any unregulated waste;To strive for increased self-sufficiency in the management of hazardous waste and to minimise hazardous waste export;To minimise the environmental, health, social and economic impacts of hazardous waste generation and management. 

Revised National Hazardous Waste Management Plan

THANKING ALL MY TEACHERS AND FRIENDS FOR THEIR KIND PATIENCE

A PRESENTATION BY1.ISHITA MONDOL(ECE/2014/030)2.SUBHAM MONDOL(ECE/2014/031)3.SAYANTAN CHAKRABORTY(ECE/2014/032)4.BIKRAM DAS(ECE/2014/044)