Treatment Options for Solid Waste

¶ … Treatment Options

Solid Waste is generally described as:

• Trash (for instance dairy boxes and even coffee grounds)

• Reject (for instance metallic scrap, wall panel, and even empty storage containers)

• Sludges coming from waste materials treatment facilities, drinking water supply clarification facilities, or air pollution control establishments (for instance scrubber slags)

• Manufacturing waste products (for instance manufacturing process contaminated waters and non-waste-water sludges as well as solids)

• Other dumped supplies, such as liquid, semisolid, solid, or even contained gaseous supplies caused by industrial, business, mining, farming, and local community pursuits (for instance boiler slags).

The phrase solid waste isn't restricted to waste products which are physically solid. Numerous solid wastes tend to be liquid, whilst some others happen to be semisolid or even gaseous.

The word solid waste, as based on the Statute, is extremely wide-ranging, including not just the conventional non-hazardous solid waste products, like city trash as well as manufacturing waste products, but additionally hazardous waste products. Hazardous waste materials, a part of solid waste, are controlled with RCRA Subtitle C. For reasons for controlling hazardous waste products, EPA set up by legislation another meaning of solid waste.

Land filling of solid waste nonetheless remains probably the most extensively utilized squander management technique. Americans land filled roughly 54.3% (131.9 million tons) of city solid waste in '09. Numerous local communities are having issues allocating brand new landfills, mostly consequently of heightened citizen issues concerning the possible dangers and even aesthetics related with owning a landfill within their community. To decrease dangers to well being and also the natural environment, EPA created minimal standards that solid waste landfills should meet.

Experimental

Causes of Contaminants within the Atmosphere

Arsenic

Arsenic happens within the atmosphere each from all-natural as well as anthropogenic sources. The main all-natural causes of arsenic emission towards the atmosphere are: igneous rock (basalt); warm springs (geo thermal); sedimentary rock (inorganic/organic shale, clays), metamorphic rock (slate), sea water, mineral remains; as well as volcanoclastic releases/materials (USEPA, 2003).

Significant anthropogenic origin for the discharge of arsenic towards the atmosphere consists of solid waste disposal, wood preservatives, pesticides, industrial emissions, mine tailings and even burning byproducts from non-renewable fuels (mainly coal). Arsenic is present within the atmosphere each, as organic and inorganic types. Inorganic arsenic may happen within the atmosphere in a number of forms however in all-natural waters and thus in safe and clean water, it mainly is present as arsenite, As (III) and even arsenate, As (V) (USEPA, 2000).

Organic arsenic kinds are even though rich in sea food however they are fairly a lot less dangerous to overall health in comparison with inorganic arsenic and therefore are easily removed from the human body. The types of arsenic existing will rely on the kind and levels of sorbents, pH, redox possible (Eh), and even microbial process within the atmosphere where it is operational (Yong & Mulligan, 2006).

Arsenic is really a recognized human carcinogen and it has been categorized in Group One of the Top priority Substance Catalog which recognizes substances such as effluents, chemicals and even wastes which are dangerous for the atmosphere or even amount to some risk to human well being (Health Canada, 2006).

Throughout North America the arsenic levels in all-natural uncontaminated soil as well as sediments vary from 4 to 150 mg/kg whilst in uncontaminated surface area water as well as groundwater, the focus varies from 0.001 to 0.005 mg/L (Wang & Mulligan, 2006). Nevertheless, much greater amounts, ten to thousand times the Interim Maximal Appropriate Concentration (iMAC) on account of anthropogenic inputs, happen to be documented in soil, air along with sediments; surface area water and even groundwater; and biota in numerous parts of North America based upon localized geology, hydrogeology as well as geochemical features involving the aquifer (Wang & Mulligan, 2006).

Imminent changes towards the drinking water specifications pertaining to Saskatchewan (EPB 207, 2006) may restrict overall arsenic level to 0.01 mg/L within consuming waters. The actual regulating restriction for Arsenic within drinking water since December 2009 has been 0.025 mg/L.

NORM

Naturally Occurring Radioactive Substances (NORM) exists in trackable levels within surface area waters, soils, groundwater as well as rock and makes living as a result of radioactive corrosion involving uranium (U-238) and even thorium (Th-232). Uranium is actually mobilized via rock from the uraninite weathering (UO2) and also by the act of surface area waters as well as groundwater oxidative dissolution involving uraninite directly into uranyl ion (UO22+) (Canada Gazette, 1998).

The main focus of this document will remain on waste treatments methods for arsenic specially those coming from coal and metal mines in mineral rich countries.

Solid Waste Landfill Treatment

Landfill Environment and Contamination

Arsenic

There are a number of factors that can affect arsenic's mobility in the landfills some of these factors are initial leaching and adsorption. The reactions that take place because of biological activity, pH conditions and redox are known as adsorption. The distribution of arsenic can get affected by microorganisms that can accumulate, transport and transform it. There are different kinds of anaerobes that can reduce the arsenic compounds from methylated to di- and tri-methylarsine in the presence of anaerobic conditions (Jing et al., 2005). Adsorption is a phenomenon that is dependent on pH and with regards to arsenic adsorption will have lower values of pH for As (III) and higher As (V) at the neutral pH (Pinel-Raffaitin et al., 2007).

The TCLP (Toxicity Characteristics Leaching Procedure) (1311, USEPA) is a procedure which is used to find out if the dangerous compounds present in the waste have the probability of leaching out and if they can become a danger to environment or the public health (USEPA, 2006). However this Toxicity Characteristics Leaching Procedure does not simulate the redox potential, alkaline pH and biological activities that typically take place in the landfill environment in an adequate manner (Ghosh et al., 2004).

The mobilization of arsenic is favored by all of these environmental parameters from metal oxide sorbents. In fact, according to TCLP much of the solid residuals that have arsenic bearings from the water treatment process might get disposed off into landfills of non-hazardous kind (Ghosh et al., 2006). Therefore, the realization of this fact is very important along with the conduction of leaching test so that the presence of arsenic could be checked with regards to the usual conditions of the landfill environment before it is disposed off in harmless landfill.

Results

In many of the developing countries it is preferred to dispose of the solid waste in open dumps rather than landfills. Refused is just simply dumped in the areas that lay low in open lands. The characteristics of open dumps are absence of leachate management, no or few operational measures like user registration, lack of engineered measures, controlled compaction of waste or number of tipping fronts (Zerbock, 2003).

By following this method the waste in dumped in a very haphazard manner and this is neither safe nor hygienic. But the fact of the matter is that when it comes to tipping waste, the developing countries don't have a lot of choice but to follow this method. It is the opinion of the local government due to the lack of institutional and financial resources at the moment the disposal of waste in this uncontrolled manner is their best option. Mostly the local governments don't have enough funds and power and they are facing the problem of increasing population as well therefore, it is very difficult for them to come up with enough amounts of funds that would enable them to properly build engineered landfills.

Operated or semi-controlled landfills are used in some of the emergent countries. In these types of landfills the waste is tipped at a specified place and then it is compacted and covered with topsoil every day in order to prevent any nuisance. All kinds of waste whether its clinical/hospital, municipal or industrial gets dumped without any segregation. There is no engineering of the dumpsite done to manage the emission of gases from landfills or to manage the leachate release.

In the developed countries the sanitary landfills can be found and they are engineered in a proper manner. These countries have proper systems through which the generation of leachate is intercepted along with the arrangements to control the gases developing from the decomposing waste. These facilities are very expensive to construct and until and unless there isn't some kind of outside funding, the developing countries can't afford them (Oyaro, 2003).

Due to the fact that the word 'landfill' hasn't properly been defined it gets misused a lot. There is still a lack of clarity in the operational aspects of this word due to the lack of proper definition. Although the word landfill refers to a site with properly engineered waste removal system and that also has very little, if any, impact on the environment but loosely the word landfill refer to a dumpsite of any kind. There are people who prefer referring to the open dumps as the disposal sites. Here in this paper we will be using the term open dump to only refer to the disposal sites that are uncontrolled, and which are also the center of discussion here.

Usually leachate is associated with the open dumps and this is in liquid form. The production of leachate takes place in such as manner that when the percolation of rain through the waste dump present on the disposal site takes place, it creates leachate. This water gets accumulated at the bottom of the dump. The organic compounds and the inorganic constituents that are formed by the microbial activity and are present in the actual waste give rise to leachate. In leachate there are traces of the metal such as zinc, lead, manganese, copper and iron. Therefore, leachate contaminates the groundwater as well. The water gets contaminated by dumps as well when the allochthonous organic matter gets into the water through surface runoff because of which leachate is carried from the disposal site as well.

Discussion

Dangers from Solid Waste sites

A lot of serious health issues are created for the animals, humans and environment due to the way that the solid waste is disposed off in an uncontrolled manner. There are economic and different welfare losses that occur due to this improper manner in which the waste is disposed off (Zurbrugg, 2002). There are many different ways through which the environment is being degraded. When the soil comes into contact with the leachate and solid waste it gets contaminated.

The dumping sites that originally were located away from the communities are now coming closer and closer to the housing estates due to rapid urbanization which has decreased the distance between municipal boundaries and housing communities (Schertenleib & Meyer, 1992). Because of this public has started to oppose the existence of these dump sites more and more as they cause dust, odor and various other kinds of nuisances. The people who live near to the dumpsites have the chances of coming in contact with the diseases that are related with the dumps and their waste materials. There was a study conducted by Oyaro (2003) in which tests were performed on 328 children who lived closer to Dandora dumpsite. According to the study there were excess lead concentrations present in the blood of half of those children. These kids were also found to be suffering from asthma, skin infections, anemia and many other respiratory diseases. All of these diseases have an association with the toxins present at the dumpsite, which had rubber, chemicals, plastics, hospital waste and wood present in it (Environmental News Services, 2007; Oyaro, 2003).

Way Forward

The open dumping site present in sub-Saharan Africa will remain open even though it is causing a lot of health issues. The main reason behind this dumping site not closing down is the fact that many of the countries present in the region don't have enough resources to build a proper landfill. These countries have many other serious issues that they need to deal with like providing food to the starving people who don't have much to eat due to the repeated droughts. Therefore, building landfills isn't the top priority for these countries as; they have many other serious issues to deal with. However, some kind of efforts should be made to improve the conditions of these landfills as; they are proving to cause serious health risks.

Following are some of the suggestions that can be adopted by them to improve the conditions of these landfills:

• Waste management Integration: Waste recycling, reduction, composting and reuse fall in the category of integrated waste management. Speaking from the point-of-view of ecology, compositing has proven to be an excellent method to recycle biodegradable waste (Zurbrugg, 2003). Although it should be kept in mind that small and large scale composting projects have failed due to the fact that no proper attention was paid to product quality and marketing of the projects. Establishing a target market and requirement for the compost product is very important. The composts should be made use of by the local authorities in their own municipal gardens and flower beds before they start looking for a market for the compost.