Analysis Of The Hazardous Waste Management Methods

The most ideal way to manage the waste is reduction of waste generation. However, due to increasing population and demand, the generation of waste and minimizing the waste generation currently is unavoidable. Hazardous wastes can be found in different physical states such as gaseous, liquids, or solids. hazardous waste is a special type of waste because it cannot be disposed of by common ways like other by-products of our everyday lives.

Hazard waste must be managed depending on the physical state of the waste, treatment and solidification processes. The industrial and commercial hazardous materials are produced in abundance from most of the processes involved. United Nations Environment Programme (UNEP) projected that more than 400 million tons of hazardous wastes are produced collectively each year, mostly by developed countries. These harmful waste and pollutants possess significant destruction to human beings and environments if not dealt with properly.

According to EPA 2007, waste can be classified as fill materials, solid inert, putrescible and prescribed waste. Fill materials are the waste which are not contaminated, or the contamination concentrations do not exceed specified limits. This includes soil, gravel and rock of naturally occurring materials which may be suitable for site filling and levelling depending on contamination levels (EPA 2007). Contamination level of the fill materials will be assessed by implementing different criteria such a site history (EPA 2007). Solid inerts are building materials such as concrete, plastic, glass, metals, dry timber and bitumen which can be reused, recycled and used for landfills.

This is hard waste which has negligible effect on the environment, and this can be reused or recycled depending on the contamination level (EPA 2007). Solid inert waste also can be used for landfills. Putrescibles are the food or garden waste from commercial and industrial sources such as vegetable processing, butchers and domestic garbage which can be used for composting, stockfood, recovery of energy and landfills (EPA 2007).

Prescribed waste are the contaminated soils which considered hazardous according to their chemical reactivity, explosiveness, oxidising ability, corrosiveness, toxicity, flammability and other properties. Depending on the type of waste and hazard category, various treatments and disposal methods such as on-site remediation, off-site remediation and licensed landfills will be used to treat prescribed waste.

According to Environment Protection (Prescribed Waste) Regulations 1998, the classification hazardous wastes have been generated by their potential for reuse, recycling, recovery of energy or treatment. The level of hazard can be used to determine the suitability of the waste management facilities, hence ensure the appropriate environmental protection. According to EPA Victoria, hazardous wastes can be classified as Category A, Category B, Category C and clean fill. Category C can be further sub-divided into Category C(a) and Category C(b) (EPA 2001).

Category A prescribed industrial waste requires a very high level of control and constant management (EPA 2001). Unused arsenic agricultural chemicals, some filter cakes with high metal contents and highly concentrated gasworks contaminated soils are some of the example of Category A type of wastes (EPA 2001). As per EPA (2001), they are not suitable for containment, and they must be treated to reduce hazard classification for suitable containment or safely stored. Category B prescribed industrial waste requires a high-level control and ongoing management. The prescribed industrial waste containment facility must be used for containment of this type of wastes (EPA 2001).

Some filter cakes with high metal contents and low concentrated gasworks contaminates soils are some of the examples of Category B type of hazardous wastes. As per EPA (2001), Category C prescribed industrial wastes pose low hazards. They can be subdivided into C(a) and C(b) which includes wastes with potential amenity effects and other low environmental risk wastes respectively. Low level contaminated soils, scallop shell wastes and filter cake with low metal content are some examples of Category C wastes (EPA 2001). These types of wastes can be received to municipal landfills (EPA 2001).

According to Department of the Environment (2017), hazardous waste can be treated and disposed under four waste management types as recycling, energy recovery, disposal and long-term storage. Recovery of hazardous materials and recycling them is a great method reducing hazardous waste. Recovery and recycling of hazard waste can be divided in to three categories (Technologies n.d.).

In plant recycling can be performed by waster generator to recycle raw materials, process streams and by-products for hazard waste prevention (Technologies n.d.). Commercial offsite recovery can be used for hazard waste from several processes and small waste quantities produced by several manufacturers (Technologies n.d.). For example, there are oil filter recycling facility and Fluorescent tube recycling facility are located at Willawong, Queensland (Ace Waste n.d.). Material exchanges can be used to eliminate waste by allowing raw material users to identify waste generators producing a material that could be used (Technologies n.d.).

Recovery and recycling technologies that can be used to hazardous waste can be vary in different stages of development. The least expensive and the most common method is physical separation. The type of waste recycling can be applied to is limited due to the low separation efficiencies. Complex component separation for recycling is and expensive operation so as the chemical transformation methods. Due to the number of processing steps involved, recovery and recycling can be expensive than disposal methods of hazard wastes.

Energy can be recovered from the hazard wastes by converting no-recyclable waste materials into usable heat and electricity. Renewable energy sources can be generated through this process. Carbon emission can be reduced by offsetting the need for energy from fossil sources and methane generation can be reduced from landfills (Wikipedia 2019). However, energy recovery from waste power plans cause more air pollution than natural gas power plants (Wikipedia 2019).

Generally, the power plants which generates electricity from waste cost more than the coal powered plant or natural gas power plant (Wikipedia 2019). Energy can also be recovered as fuel through various processes such as combustion, gasification and anaerobic digestion (Wikipedia 2019). For an example Australia has a few of these plant in the Ti Tree Bioenergy Facility (Queensland), Woodlawn Bioreactor (New South Wales) and the Thermal Destruction Plant (South Australia) (Veolia n.d.).

Depending to the hazard waste classification, waste can be disposed in various disposal methods. Firstly, hazardous waste can be disposed in landfills which designed with double layered no-porous materials such as HDPE to prevent leaching waste into the ground (Southern Council 2019). There are several number of hazard waste landfills located throughout Victoria and Australia. Once the landfill is full it can be covered to prevent rodent and insect entering. This method takes a lot of space.

The hazardous waste can be incinerated into incombustible residue by first detoxifying waste to reduce the release of toxic gas. (Southern Council 2019). Incineration is ideal for the areas with minimal spaces for landfill even though its high operation cost. Incineration of hazardous waste can be used to produce steam for running turbines to generate electricity (Southern Council 2019).

The next disposal method is to deposit hazardous waste in the deep sea to minimize the impact of ground water sources (Southern Council 2019). The waste needs to be treated before dumping it at the sea to minimize the danger to marine life (Southern Council 2019). Finally, underground disposal of hazardous waste can be used mostly radioactive waste. This will be done in partially active or inactive mines which meets relevant technical and geological criteria (Southern Council 2019). This is the most ideal and economical way of disposing radioactive waste (Southern Council 2019).

Long-term storage is another method applicable to treatment of hazardous waste. Facilities can be constructed to store hazardous wastes for long periods (usually over 10 years), typically until an economically viable treatment or disposal solution is developed (Department of the Environment 2017). Abandoned or closed mining facilities with impermeable geological layers, dry soil, allowing long term disposal can be used for long-term hazard waste storage. Engineering barriers can also be added to fully contain the waste from any possible pathways to biosphere (World Urban Campaign n.d.). It is also required to assure that there is no interaction between underground operations and surface land uses.

This offers safe and controlled environment to store waste and monitor them (World Urban Campaign n.d.). Hazardous waste in landfills can be relocated to underground storages to reduce polluting urban areas. Currently, Tellus Holding Group is looking for approval to construct 2 of these storage at in the Simpson Desert and in the Amadeus Basin of Northern Territory (Tellus n.d.).