Water Treatment Process and Conservation - Report Example

Water treatment process and conservation Student’s Name Name of Institution 16th May 2012 Outline I. Informative summary...............................................................................................3 II. Introduction............................................................................................................4 III. Conventional wastewater treatment process...........................................................4 IV. Problem facing conventional wastewater treatment process...................................6 V. Advanced wastewater treatment process................................................................6 VI. Membrane filtration process...................................................................................7 VII. Ultraviolet irradiation process..............................................................................11 VIII. Water conservation within the company..............................................................12 IX. Conclusion...........................................................................................................13 X. Recommendation.................................................................................................13 Informative Summary and Recommendation World industries consume 23% of the total usable water. Industries use this water for washing cooling and processing products. The wastewater from these industries is harmful to public health. This has prompted water and wastewater treatment processes to be reviewed in many industries (Zhou & Smith 247). Research carried out shows that the new implemented technologies in the water and waste treatment procedures have enabled these industries to reduce contaminants in the water systems as well as water conservation. This paper will look at the new technologies such as membrane filtration process, alternative oxidation process, and ultraviolet irradiation. The paper further compares the new technologies with the conventional waste water treatment process which is widely used in many industries. Better treatment processes and control measures will help to ensure water utilities meet the stringent measures to provide quality water to the public. The increased knowledge of water pollution and public desire to better and quality water has prompted the development of wastewater treatment process (Zhou & Smith 247). The water treatment process removes contaminants of chemical and microbial elements. These elements are harmful to the environment as well as public health. Introduction Water treatment process is one of the most crucial processes in any industry. Various treatment processes put in place to ensure waste water is recycled and reused in the industry (Whiting & Joanne 1). The industry is forced to treat wastewater since the world is rapidly growing in population and water as a major resource is increasingly getting scarce. In order to attain a sustainable wastewater management, the treatment plant should be feasible, well planned and effective. In the recent times new technologies such as membrane filtration, ultra violet irradiation and advanced oxidation processes have been incorporated in the wastewater treatment process. With the increase in manufacturing industries, these new technologies are applied extensively to keep up with the growing scale of production. However, the process encounters many constraints which slow or hinder the success of treating the wastewater. This thesis will look at the water treatment process applied by the Coca-Cola Company. Source: (Swayer et al. 44) Conventional wastewater treatment process Before the invention of new wastewater treatment plants several industries had installed the conventional water treatment plant (Whiting & Joanne 2). The water treatment process had five main stages (Metcalf & Eddy 10). In the first stage water is screened as it enters the treatment plant. Here contaminants such as wood rocks and dead animals are sieved out (Metcalf & Eddy 12). The sieved materials are taken to the land fill. In the second stage the wastewater is pumped up to the aeration tanks. At the aeration tanks the wastewater is shaken up to expose harmful dissolved gases such as hydrogen sulphide to the atmosphere (Metcalf & Eddy 17). Air is pumped through the water to replenish the oxygen that was used up by the decaying matter in the wastewater. The pumped air also keeps organic material suspended on top of the water and forces the heavy sediments to settle out. These sediments are pumped out of the tank to landfills. The wastewater is then pumped to a second section of sedimentation tank where sludge is removed. The sludge at this stage composes of organic matter is pumped out to large tanks known as digesters (Metcalf & Eddy 33). As the sludge is pumped out the scum which composes of light molecules of materials like oil plastics and soap are thickened and pumped to the digesters as well. Afterwards the water is filtered through sand and carbon particles to reduce the amount of iron, remove bacteria, and reduce turgidity and colour. The last stage is killing bacteria. The bacteria are eliminated by introducing chlorine to the treated water (Metcalf & Eddy 59). However, this poses as a health risk if the chlorine is not removed or neutralised. The water is then rechanneled back to the source for reuse. In most industries they have divided the treatment process into four sections (Shariff et al. S62). The first section is the preliminary treatment where incoming raw wastewater is strained, and all large objects are removed. The primary treatment stage it is similar to sedimentation process. The liquid is treated biologically. Next the water is transferred to the secondary treatment stage where up to 90% of organic matter is removed. The process takes place in the aeration tanks. Next is the tertiary stage where disinfection is the main activity (AWWA Water quality and treatment 12). Disinfection methods include; chlorination, use of ultraviolet light, and ozonation. Source: (“Conventional Wastewater Treatment Process”) Problem facing conventional wastewater treatment process The major problem with the conventional wastewater treatment comes in at the disinfection stage. This happens during the chlorination of residual. The process generates harmful chlorinated organic compounds. This residual is toxic to marine life. This forces industries to incur extra cost of de-chlorinating the effluent (Cornwell & Lee 61). When using ultraviolet light to disinfect the residual, the industry has to frequent replace the UV lamp. On the other hand, the ozonation method requires high cost maintenance and generation of the ozone. Another problem with this method is the inadequate automation of the process. It requires an iterative approach in order to arrive at a solution. The process tends to overlook at the measures of reducing turgidity and hardness of water. The process itself is time consuming and does not predict future process behaviour. Additionally it gives many convergence problems. This makes it difficult to achieve a set point target. The treatment process has locked out any efforts of redesigning a robust control scheme (Cornwell & Lee 62). Advanced wastewater treatment process The environmental agencies in the world have come up with water protection policy that regulates industries water usage and treatment. The Coca-Cola Company is one of the industries that adhere to this rule. Over the years this soft drink company has excelled in reducing the level of contaminants in the company's water system. The company operates with a policy of returning to the environment 100% of the water that has been used in manufacturing (Shariff et al. S64). The success in its water management system has seen the company coming up with its own new mineral water brand (“Resources” 23). However, just like any other industrial process the water treatment process of this company faces serious short comings. The industry is faced with a huge problem of diminishing water resources and high rate of population increase. Furthermore, the growing market and the highly developed treatment plants have resulted to the increase in the cost of wastewater treatment (AWWA Water quality and treatment 23). Finances and funding of the treatment plants still remains to be the major headache for this company (Whiting & Joanne 1). Membrane filtration process The company uses the membrane filtration process as its initial process in the wastewater treatment process. This process is injected in the system at a low pressure, and contaminants are filtered out by the membrane (Zhou & Smith 248). The separation process uses a semi permeable membrane to partition the feed in water inlet into two sections. One section of permeate contains water which is passing through the membranes, and the other section contains the contaminants being filtered out (AWWA 94). Material Membrane Separation process Ceramics (aluminium oxide, titanium oxide. Silica) Microfiltration, Ultrafiltration Sintered metals Gas separation Micro porous Carbon Hollow-fibre membrane gas separation Micro porous glass Hollow fibre Polypropylene Ultrafiltration Polysulphide Reverse osmosis Polyamide Gas separation Polycrylonitrile Ultrafiltration Cellulose Microfiltration, ultrafiltration, reverse osmosis Source: (Zhou & Smith 249) This company utilises the reverse osmosis as the main type of membrane filtration. This type of filtration is quite efficient to soft drink companies as compared to other membrane filtration such as Nanofiltration, ultrafiltration and microfiltration (Zhou & Smith 248). The reverse osmosis main mechanism is diffusion and exclusion. It retains 100% of the water injected in, and has a very low permeated flux. This type of filtration has the smallest pore, and it makes it suitable for removal of unwanted sediments and impurities in water. The comparison of the filtration is shown in the table below. Membrane Separation size (µm) Main mechanisms Typical trans-membrane pressure, Δp (MPa) Permeate flux Reverse osmosis 0.05 sieving 0.03 – 0.3 High Source: (Zhou & Smith 249) Reverse osmosis is considered to the best method of removing dissolved organic compounds in water. The Coca-Cola Company uses this filtration process to treat both municipal council water and industrial effluent (“Water Stewardship at The Coca-Cola Company” 15). The back wash and forward wash streams are performed periodically to detain minor sediments and produce clean water flow. The membrane filtration process is proposed since it separates suspended sediments and polish secondary effluents. It produces superior quality of effluents for water reuse (Zhou & Smith 251). Principle and application of membrane filtration Processes Driving forces Size range Examples Microfiltration MF Pressure (50 – 500 kpa) 10 – 0.1 m Small particles microbial cells Ultrafiltration UF Pressure (200 – 1000 kpa) Read More