Integrated Pollution Prevention and Control

Integrated Pollution Prevention and Control

With increasing industrialization, and depleting natural environment, issues pertaining to environmental sustainability have been a major concern for the environmentalists. Dumping of agricultural and industrial waste and emission of hazardous gases have significantly added to land, air and water pollution endangering everything from marine life in the sea to ozone layer up in the atmosphere.

While dumping of industrial waste has accused for posing major threats to the environment, domestic waste is as much a contributor. A large amount of domestic waste constitutes of plastic in form of fizzy drinks, burger boxes, egg crates etc. These items are made up of plastic polymers that have low recycling margins. The dumping of these wastes in municipal garbage and their inability to recycle results in emission of toxic gases.

From time to time scientists and environmentalists have tried to come up with newer, better and more efficient methods for recycling and treatment of waste so that environmental sustainability could be ensured. One of the most widely used waste disposable system in the United Kingdom, and in many other parts of the world is the waste incineration system. This is a thermal waste treatment system that involves combustion of waste through heating it at high temperatures. The pollutants are then converted into ash, flue gas and heat and are emitted into atmosphere. As more researches and in depth studies are carried out, it was discovered that incineration can have many adverse effects, both environmental and economical and therefore alternative waste management systems are needed. One good proposal in this regard is switching over to the gasification technology.

The gasification technology is much more beneficial as compared to the conventional incineration systems especially when it comes to environmental sustainability. Gasification, like incineration is also a thermal system where waste is heated at high temperatures to separate the pollutants in solid, liquid and gaseous states (Friends of Earth 2009). It is, however, different, in a way that the temperatures are maintained carefully such that the waste is not combusted and emitted into the atmosphere and the residue gases are further processed to limit atmospherical emissions (Friends of Earth 2009). This method counters some serious externalities that are caused by the use of conventional mass burn incineration system. The incineration system uses high amount natural resources for thermal treatment which adds to depletion of natural resources. In addition to that, the emission of gases in atmosphere adds to already increasing issues pertaining to global warming and climate change. Apart from that, the mass burning incineration plants are huge structures, which are not only time consuming to built, but also allegedly contribute to devaluation of property that is located in the close proximity. Incineration plants are not only huge but they also lack architectural appeal and huge chimneys adversely affect the beautification of environment. On the contrary, according to hill (2010), the new gasification technology, which although is in early stages, if implemented can have immense benefits over the conventional systems.

According to hill (2010), the gasification technology, technically referred to as Advanced Thermal Technologies (att), uses much lesser oxygen amounts as compared to conventional incineration systems. This means combustion can be minimized and air emissions can be reduced. Hill (2010) further claims that the Advanced Thermal technology plants are composed of smaller units, which are easier to build and are more flexible as compared to their conventional counter parts.

One of the major accusations imposed on the conventional incineration system is that the energy generated from the treatment process can only be utilized back in the incineration process for further treatment. On the other hand, the energy recovered from the treatment processes involved in the Advanced Thermal Technologies can not only be reutilized in the further processes but can also be used in other applications such as electricity generation (Hill, 2010). This implies that this process can also act as an alternative energy generation system thus helping in conservation of natural resources. On an economic side, hill (2010) claims, that energy produced using the Alternative Thermal Technology Systems is much more efficient as compared the incineration system and can increase income from power generated. Moreover, according to Colls (2002), the energy rich gas, technically referred to as 'syngas', produced has potential applications as energy fuel and petrochemical feedstock. Using generated energy as an alternative fuel would mean other natural resources and fossil fuel can be conserved.

Fabric Filters (FF) Versus Electrostatic Precipitator (ESP)

As mentioned earlier, the conventional incineration is greatly accused for the environmental hazards caused by the combustion processes involved in the process. Since United Kingdom and many other countries are greatly dependent on this mass burn incineration process, environmentalists have been endeavoring to bring about changes within the processes involved in the incineration process such that the process pose less environmental threats.

According to Fantom (2005), the introduction of Environmental Protection Act in 1990 by the government of United Kingdom resulted in stricter pollution controls and more conservative emission policies. Industrialists and waste management companies were forced to reconsider the processes involved in waste management so that more environment friendly processes can be employed. The most widely used method was using Bag Filters or Fabric Filters. A more environmental friendly alternative proposed by the environmentalist is the use of Electrostatic Precipitators (ESP). According Fantom (2005), although Electrostatic Precipitators contribute less in environmental contamination, however they are very sensitive to dust. Due to their low resistance to dust, the efficiency of performance of Electrostatic Precipitators can be greatly affected. On the contrary, Fantom (2005) claims that Fabric Filters are much less sensitive to dust as dust particles are left as residues on the fabric's surface. However, some industrial operations require to increase temperatures in order to increase operational efficiency, which can result in a significant increase in contamination caused by use of Fabric Filters (Fantom, 2005). Another problem with the Fabric Filters is that as bag life increases, the chances of emissions also increase thus further increasing contamination.

According to Fay and Glomb (2002), Fabric Filters consume 80% to 90% more energy as compared to the Electrostatic Precipitator. Moreover, the chances of fire and accidents are much more in using Fabric Filters.

On the other hand, the only single negative aspect that is associated with use Electrostatic Precipitators is their resistance to dust. According to Kneese and Bower (1979) both Electrostatic Precipitators and Fabric Filters have room for upgradation. Fantom (2005) claims that Fabric Filter can be upgraded for improved emissions while the Electrostatic Precipitators can be upgraded for dust abatement. The economic and cost considerations show that choosing the up gradation of Electrostatic Precipitators can not only proves to be more environment friendly, but also more cost efficient as less energy is consumed, thus dust resistance and operational efficiency increases and the long-term average costs can be decreased along with improved emissions. The initial up gradation cost for both the Fabric Filters and the Electrostatic Precipitators is almost the same. The Fabric Filters are uneconomical in the long-term as filter bags have relatively shorter life and as the bag life matures the emission rates starts to increase again, which means another up gradation will be needed. This makes Electrostatic Precipitators more economical.

Reducing Heavy Metals in Landfill Leachates

Landfill Leachates are another major concern for environmentalists when it comes to waste management. Leachates are liquids that drain through landfills and there is a potential threat that pollutants present in the Leachates may enter the environment.

According to Robinson and Maris (1985), more than 90% domestic and industrial waste is disposed of using landfill methods in United Kingdom. Harris and Nelson (2007) state that toxic emissions from metal content present in landfill pose immense environmental hazards. There is a great chance that toxic content present in the metal contain is transferred into the environment through the landfill leachates. Therefore, it is important that such metal content must be removed from the landfill Leachates. There are various methods for removal of heavy metals from landfill leachates. This can be done by physical, chemical and biological techniques.

According to Ifeanyichukwu (2008), heavy metals can be removed from leachates if subjected to anaerobic conditions. This can mainly be done by using biological processes and using membrane technology.

Simple reverse osmosis methods and membrane technologies such as Electro dialysis and ultra filtration can be employed to separate solid content from leachates. Physical methods such as coagulation and flocculation can also be used to remove suspended solids. Ifeanyichukwu (2008) suggests that Biologically Aerated Filters can be used for removal of heavy metals from the leachates. This method involves using a treatment tank that has an aerated fixed film submerged in the tank. The film holds back the suspended solids in leachates thus separating the heavy metals.

Ifeanyichukwu (2008) also suggests use of membrane Bioreactors. These Bioreactors generate high biomass concentration thus increasing efficiency of separating solid effluents from the leachates. Ifeanyichukwu (2008) claims that flotation is a good technique which can be used for removal of metals from leachates. This method makes effective use of ability of metals to float on surfaces of leachates on their own. Due to the high proven efficiency of this method, it is widely used for removal of heavy metals such as iron and humic acid from leachates in many parts of the world.

Removal of Plastic from Municipal Waste

Plastic is a non-biodegradable waste that has low recycling margin. Unfortunately, plastic is widely used in everyday products is heavily present in the municipal waste. The environmental threat posed by the presence of plastic in municipal waste is another major issue. Major plastic types that are commonly found in UK municipal waste include PET, high density polyethylene, polyvinyl chloride, low density polyethylene, polypropylene, polystyrene, and other plastics such as melamine. Major source of these types of plastic are fizzy drink bottles, bottles of detergents and washing liquids, plastic plates cups and spoons, bin bags, microwavable trays, margarine tubs, food trays and packaging material for some toys and electronic items. According to Waste Online (2002), approximately three million tones of plastic waste are generated in United Kingdom every year. There are various alternatives to remove and recycle plastic e from municipal waste. According to Foster (2008), Film Separation is an efficient method to separate plastic from municipal waste.

Thermal methods such as Gasification can also be used to remove plastic waste from municipal wastes.

The most common method of removing plastic from municipal is physical collection. Labor can be employed to collect plastic ways physically from the municipal dumps and bring it to the recycle plants. Plastic can be removed and recycled using a combination of various processes including Film separation, whole item separation, Fake dry cleaning, Flake separation. This is a mechanical recycling method and is technically and economically feasible. A major constraint involve wit this mechanical removal and recycling method is that it is not effective for bottled plastic wastage. As mentioned earlier that a large amount of plastic waste that is present in the municipal waste dumps is comprised of bottle plastic waste. The limitation of mechanical method that is only effective for non-bottle waste implies that this method cannot be completely depended upon for effective and complete removal of plastic from the municipal dumps.

Considering the limitation of mechanical techniques of removal and recycling plastic waste. It is more feasible to contract physical labor in order to collect and remove solid plastic waste from the municipal dumps.

There are other forms of mechanical separation processes available too. The contaminants separation method is used where waste is put into cyclone separators and the turbines are rotated at very high speed. The contaminants are then separated from plastic in the separator. This is a very easy to use method and is also cost efficient and environment friendly. The extrusion method involves feeding the flakes into an extruder. This is a thermal treatment method where the flakes are pushed through a die which converts plastic flakes in long polymer products. This bring plastic in a re usable form.