Hazardous And Industrial Waste Disposal Issues Environmental Sciences Essay

The handling of the hazardous materials is complicated by the increasing magnitude of waste generated each year, the variety of materials that become refuse, the vast array of chemicals that may eventually leak from containers and burial sites; the difficulty of monitoring landfill sites for leachates, the difficulty of adequately sequestering waste to inhibit leaching, the variability of soils and their sorption capacities for leachates, the variability of soil permeability, and the cost of safe disposal versus that of assessing real or imaginary risk (Chian, E.S.K., and DeWalle, F. B., 2001).

Due to these complexities, the removal of the hazard from hazardous wastes requires a systems approach (Brunner, D. R., and Carnes, R. A., 2004). For example, the least cost of an activated sludge and carbon adsorption system is a function of both processes operating simultaneously. The optimal design range for the least-cost system could not be ascertained by assessing the performance of the two processes independently.

Background of the Study

An important consideration over the next several years will be the impact of the toxic effluent limitations which should be discussed in the Philippine Government. A rational approach to defining toxic and hazardous wastes is to view a biological entity in equilibrium with its environment and attempt to quantify those insults on the biological entity that causes a disequilibrium or negative response. In the study of hazardous substances, two parameters of importance are dose and time (Atkins’, P. R., 1998). An important point to note about the tests for acute and chronic toxicity is that, although the tests might isolate the relative toxicity of a substance, they are virtually useless for predicting levels at which no toxic effects will occur.

The decision to incinerate depends on the type of hazardous solid waste, moisture content, organic fraction, heat content, economics, and the availability of land (Fennelly, P. F., et al., 1999). Whenever feasible, incineration should be considered. This process significantly reduces the volume, generally will also detoxify the waste, and gives a product amenable to compaction and containerization resulting in enhanced ease of handling. Incineration processes include the stationary hearth incinerator, the multiple hearth furnaces, the rotary kiln, the fluidized bed reactor, and the open pit incinerator. Each type of incinerator operates properly only within a limited range of temperatures. Generally speaking, for efficient operation, the materials burned must have a fairly uniform BTU value. This may require the blending and mixing of wastes to be burned and the addition of auxiliary fuel. Capital costs for incinerators are high, particularly for the smaller units. In some cases, complete elimination of the hazardous agent may be obtained through incineration.

The result is that potentially toxic and hazardous substances can be identified, but criteria for safe exposure are lacking; therefore, these wastes have a special stigma imposed on them because of the possibility of unknown effects (Farb, D., 2007). This psychological stigma can often impede rational implementation of treatment and ultimate disposal schemes for these toxic and hazardous wastes. No matter what treatment or ultimate disposal scheme is selected, man-made residuals will eventually reside in the atmosphere, lithosphere, or hydrosphere.

Objective of the study

An understanding of the reactions and forces controlling the movement of a pollutant in the environment is essential if effective treatment and ultimate disposal of toxic and hazardous wastes is to be attained. For example, decisions involving chemical waste disposal will be based on knowledge of chemical form, persistence, acute or chronic toxicity, genetic effect, flammability and reactivity.

Hypothesis (Null Hypothesis)

There is no environmental effect from hazardous and industrial wastes.

Significance of the study

A study of the natural environmental forces and reactions which maintain equilibrium of systems illustrates quite well the basic principles of handling toxic and hazardous substances by transforming them into less harmful substances or isolating them in a repository such that release into the dynamic parts of the environment occurs at such a low rate that toxic effects are not realized.

Literature Review

The greatest fallacy with the environmental crisis and residuals disposal is that acceptable environment can be obtained by reducing or even abolishing our dependence on “technology” or by neglecting cost considerations. The fact is that residual wastes and their ultimate disposal will require technological solutions-and many of them. Finally the cost to support waste treatment, recycle, reuse, collection and disposal must be borne by the consumer in the form of higher prices and by the taxpayer in the form of higher taxes.

The handling and disposal of toxic and hazardous wastes is a multipronged problem that involves: (a) separation and waste partitioning, including process control through technological improvement, waste stream separation, and recycling; (b) inplant waste treatment, including chemical, physical, and biological treatment; (c) in-plant waste disposal, involving recycling, containerization, and incineration; (d) volume reduction through drying, incineration, and compaction of end-of-pipe residuals; (e) translocation involving storage, containment, and transportation; and (f) ultimate disposal considering isolation through minimization of water movement, and maximization of passive barriers through which migration of hazardous materials might take place.

Separation and waste partitioning have the distinct advantage of reducing the volume of solid wastes to be handled. Process control entails separating the hazardous agents at the source. The initiation of control on the toxic wastes at this point is the most cost effective with respect to minimizing the volume and segregating the hazardous wastes.

Chemical treatment schemes involving techniques based on chemical precipitation, oxidation, photochemical degradation, and pH adjustment can be employed to isolate or detoxify certain hazardous agents. Toxic heavy metals such as lead and cadmium can be isolated by hydroxide precipitation (Rouse, J. V., 2004). In liquid waste streams, numerous physical treatment schemes are possible for separation and partitioning of the hazardous agents. The bulk form of the solid wastes limits the implementation of most physical treatment techniques.

Biodegradation of hazardous substances such as certain hydrocarbons, pesticides, and heavy metals (cyanide, for example), has been the subject of a number of studies. Soils, particularly the surface horizon to a depth of 1-3 ft (0.3-0.9 m), contain large numbers and varieties of aerobic, facultative, and obligate anaerobic organisms which singly or together can provide an effective biological detoxification of certain hazardous agents.

Two techniques are usually employed to achieve this component of the multiple barrier concepts. These are containment and encasement. Encasement is usually combined with one or more storage methods. The burial site itself, with proper use of clays or other liner materials, can become a container. This aspect of the multiple barrier concepts is more effective in reducing water movement than maintenance of physical integrity. A method of improving the passive barrier is encasement. The use of concrete as an encasement material is widespread. More recently, an interest in developing technology for encasement in plastics and vitreous materials has been expressed. Various encasement materials include: polyethylene, asphalt, lime/fly ash, portland cement, plaster of Paris, metal silicate, bentonite, and vermiculite.

Data Treatment and statistical Tools

The study is a quantitative study that will focus on data that presents environmental effects of hazardous and industrial waste. They will get the data from the Department of Environment and Natural Resources from year 1988-2008, to uphold consistency and prevent bias. The researcher will be using T-test to be able to test the significance of the variables.

Summary and Conclusion

Ultimately, residuals must be returned to air, land, or the oceans. The cost of disposal will be borne by the consumer, because residual wastes are generated when natural resources are processed for man’s benefit. There is a large and growing body of technical literature on waste management. Hazardous agents can be removed from wastes, although under some circumstances it is more economical to modify the manufacturing process rather than modify sections of the treatment train.

Recommendations

The removal of hazardous agents is not simply a process that occurs at any one step in a well engineered system. The materials and design of the disposal site itself afford mechanisms for detoxifying and rendering innocuous the hazardous agents in the waste. Through the use of properly engineered treatment systems and passive but multiple barriers between residuals and the biosphere, it is possible to reduce the transport of potential pollutants to environmentally acceptable levels.