However, for some application acetic acid is more preferable compared to sulphuric acid or hydrochloric acid due to it non-toxic and biodegradable characteristics. Besides, alkaline waste can also be neutralised through bubbling of carbon dioxide gases to form carbonic acid. One of the advantages of carbon dioxide gas is that it is readily available in the exhaust gas at any combustion process. On the top of that, chemical precipitation is also one of the techniques that can be applied to liquid waste stream that contained hazardous compounds. It is very effectively in removing or eliminating the heavy metals that dissolved in the waste stream.
Certain types of organisms are drawn to heavy metals and others contaminate and absorb them. (Conserve Energy Future, 2017). Landfarming – occurs when the contaminated soil is removed from the environment. Nutrients are then added to the contaminated soil. These nutrients stimulate the degradation of the contaminants (Sharma, 2012).
Besides that, zeolites are used as absorbents to remove of organic substances, microorganisms and anions, for seawater desalination membranes and fill materials for reactive permeable barriers. Wastewater contains trace amount of heavy metals such as Zn, Cr, Pb, Cd, Cu. These heavy metals need to be removed because they cause serious environmental problem. Heavy metals are removed along with other technologies including chemical precipitation, ion exchange, adsorption, membrane filtration, coagulation flocculation, flotation and electrochemical methods. Natural zeolites have shown good ion-exchange capacities for cations, such as ammonium and heavy metal ions.
The catalytic converter “turn the harmful chemicals in vehicle exhausts into harmless gases such as steam” (Woodford). These catalytic converters are essential to creating a less polluted atmosphere. An engine with and without a catalytic converter differs greatly and the reactions occurring are very significant in understanding the role of the converter;
The presence of radionuclides and heavy metals in our surroundings has become the most serious environmental concern. These contaminants or pollutants fail to degrade on their own over time and must be removed or neutralized. Microorganisms act as natural catalysts in the process of transformation of toxic metals into non-toxic ones. This is why there is an increased interest in the understanding of microbiological processes which help in remediation of these toxic wastes from the environment (Francis 1990). Microorganisms basically work by mobilization and immobilization of heavy metals and radioactive wastes.
3.5 Aeration Aeration for iron helps oxidation of certain substances. Also it can increase the agitation of iron to reduce the possibility of agglomeration and facilitate removal of passive film, which is deposited on the surface of iron, improving the effect of flocculation. However, excessive aeration will also affects contact time resulting in lower removal. Aeration can provide more sufficient oxygen to promote the anode reaction under neutral conditions. On the other hand it can accelerate the electrode reaction with stirring and shaking which decreased concentration polarization.
However, chlorine disinfection results in a wide variety of by-products. One class of chlorination by-products, known as trihalomethanes (THM 's), are suspected carcinogens. Because of concern about these by-products in the water supply, chlorine is now kept to minimum levels, and other methods of disinfection are being used more frequently. Chloramines form more stable disinfectants and pose less risk of harmful by-products, but cost more to use. Other methods focus on removing the organisms through coagulation, sedimentation, and improved filtration.
Antioxidants also may be obtained from dietary sources/ supplements. The efficacy of antioxidant intake on initiation and progression of chronic diseases will be reviewed. Introduction Oxygen is an element that is crucial for the sustenance of life on earth. It is paradoxical that this indispensable element can cause harmful effects in humans under certain circumstances. Much of the detrimental consequences of oxygen are attributed to its ability to form free radicals (1) .
Pipeline operation can also be of importance as dispersion of small hydrate crystals will be favoured by higher velocities. At low flow rates and during shutdown conditions, the crystals may settle out and agglomerate when the oil density difference is sufficient. The anti-agglomerants provide protection up to 40:60 water oil ratios (Chandragupthan et al. 2011). Typical examples of AAs include alkyl aromatic sulphonates or alkylphenylethoxylates (Pickering et al.
Bioremediation is using microorganisms to degrade contaminants to render them less hazardous. When dealing with petroleum hydrocarbons, bioremediation tends to be greatly successful. Nonetheless, petroleum contamination in soil is a complicated problem. There are many factors that come into play when trying to treat different contaminated sites. Soil type, regional climate, and types of native microorganisms are relevant factors just to name a few.