Treatment of Wastewater for Reuse Purposes - Research Paper Example

? Treatment of Wastewater for Reuse Purposes Table of Contents Table of Contents 2 Treatment of Wastewater for Reuse Purposes 3 Abstract 3 Introduction 3 Sources of Wastewater 6 Composition of Wastewater 6 Industrial Wastewater 6 Residential Wastewater 7 Application of Wastewater in Agriculture 7 Impacts of Wastewater Use in Agriculture 7 Crops 8 Public health 8 Ecological impact 8 Groundwater resources 9 Soil resources 9 Economics of Wastewater Irrigation 10 Wastewater for Industrial Use 10 Conclusion 12 References 13 Treatment of Wastewater for Reuse Purposes Abstract Municipal wastewater is composed of the residential wastewater, wastewater from the institutions, malls, community centres and commercial buildings. Industrial wastewater has different composition as compared to that of the municipal wastewater. Wastewater contains bio degradable solids, chemically degradable solids and compounds, dirt and sedimentation and pathogens. Wastewater can be filter and treated to be from all of the containments or some of the containments. Wastewater can be utilized in many applications. Wastewater can be utilized in the agriculture in both the treated and untreated forms. Untreated wastewater is rich is macro nutrients and thus the crops easily in untreated wastewater but it is not environmentally safe as it posses danger to the biodiversity of region. The chemical in the untreated wastewater can easily enter into the food chain and thus can harm the human life. Treated wastewater is not only goof for the plants but also for the environment. Wastewater can also be utilized for the industrial purposes. It can be utilized to cool down the internal combustion engines that generate power in the power plants and to reduce the temperature of the steam in the steam turbine generators. Introduction The increase in the population of the world proposed many problems. One of the major problems is the shortening in the supply of portable water. The fresh water sources are depleting as the population is increasing. On the other hand, the natural hydrologic cycle is much affected by the impact of human activity. One way to reduce the burden on the fresh water resources is to reuse the wastewater after treating it and then utilizing it for various purposes. The process of treating the wastewater not only makes the water safe of the biological environment but also for the industrial purposes. Today, an average home consumes as much water in a month that our ancestors have used in years. The modern water utility habits in urban regions made some parts of the world to remain in the water stressed regions. Most of the rivers in the world are unable to reach the oceans due to the heavy human burden on the rivers. Water reuse is the only key to reduce the impact on the portable water resources in the world. There are several techniques to treat the waste water. All the evolved processes have different economic aspects. The basic sewerage wastewater treatment system ascorbic digestion method consumes less energy and utilizes the natural biotic microorganisms to make the water safe for the environment. How in order to attain the drinkable quality, it undergoes different other steps like the disinfection, sedimentation filtration, filtration, etc. The water quality is considered to be environmentally safe after ascorbic digestion and can be used for the irrigation purposes. The water quality produced thus is rich in nutrients that are made during the breakdown of the sewage wastes and thus good for the agriculture (Drechsel, Scott, Raschid-Sally, Redwood & Bahri, 2009). In urban localities this type of water is safe after disinfection it and removing slug from it. This water is safe for drinking after undergoing different processes but most people prefer not to take this water as the primary drinkable water. It is most utilized to flush the toilets and for laundry purposes (Tchobanoglous & Burton, 2003). Water treatment can be 100 percent efficient or more than 100 percent. It means that the quality that runs though the faucet can be returned to the faucet with the similar or enhanced quality. Wastewater is characterized by amount of biodegradable wastes present in the water, colour of water (Grey, black or colourless), pH of water, presence of metals and metal oxides, presence of slug and sediment. In order to evaluate the process to clean the water, it is important to analyze the characteristics of the water. Municipal waste water mostly contains biodegradable wastes and water can be alkaline nature due to the presence of laundry waste as well as bath waste (Galbraith, 2013). Thus, that type of water should undergo the processes that degrade the biodegradable materials, balance the pH of water, filter the slug and sediment, and disinfect the water. The processes involved in the treatment of the wastewater can be enhanced to provide the water with drinkable quality. Membrane filterable methods, thermal vapour compression (TVC) and mechanical vapour compression (MVC) are the methods that can provide the water with the best quality, but the processes are much energy consuming. RO (reverse osmosis) filtration is not as much energy consuming as the rest but still consumes a large amount of energy and thus economically impacts the process. The methods used to filter the municipal waste water use biological as well as chemical methods to filter the water. After disinfection, the attained fresh water is of drinking quality but people tend to disagree to use the similar water that they flushed out from the toilet. Thus, the water filtration mechanisms in different regions are set to provide the water, which is not of drinkable quality. However, with little effort, the water can be treated to provide drinkable quality. Disinfecting the water and balancing the neutralizing the chemicals in the water can make the water to be of drinkable quality (Tchobanoglous & Burton, 2003). However, most people find the water not suitable for drinking due to the perception of the human mind that once water is flushed can never be returned to system. Sources of Wastewater Municipal wastewater generally contains wastewater from the industry, homes, storm and some amount of ground water that seeps into the sewage network. Domestic wastewater generally comes from the homes, educational institutions, small offices and commercial buildings. Industrial wastewater is from the industries, like textile, garments, laundry, food processing and packaging units and products manufacturing units. In some regions of the world, domestic wastewater and industrial wastewater are treated separately that is an efficient way to treat water. Composition of Wastewater Municipal wastewater is mainly composed of Organic matter, Nutrients, Inorganic matter, Toxic Chemicals and Pathogens. Nitrogen, phosphorus and potassium are the important nutrients that are present in the wastewater. Minerals dissolved in the wastewater are considered as the inorganic matter. Industrial Wastewater Industrial waste water is of different composition as compared to that of the residential wastewater. The industrial wastewater is composed of different chemical wastes as well as biodegradable wastes. Different industries produce different types of wastewater. Residential Wastewater Residential wastewater has more amounts of biodegradable compounds as compared to the harsh chemical compounds. It is easier to treat the municipal wastewater as compared to the industrial wastewater. Application of Wastewater in Agriculture Agriculture is the most promising industry that helps in generating the food resources for us. About one third of the world’s fresh water resources are being consumed by the agriculture. With the shortage of water, the agriculture industry is unable to provide the desired results in some regions of the world. Besides the use of technology to reduce the requirement of water, the industry requires a lion’s share from the world’s fresh water resources (De-Bashan & Bashan, 2004). Treated wastewater for agriculture can provide a substitute for the fresh water that can make the agriculture industry to excel. The major perspective of utilizing the wastewater for the agriculture is that the agriculture industry requires water with biologically generated nutrients and less filtration is required. There is no need to disinfect the water before pouring it to agricultural field. Treated municipal wastewater is best suited for the agriculture as the wastewater is rich in biotic nutrients (Pescod, 1992). Impacts of Wastewater Use in Agriculture Besides certain benefits of utilizing the wastewater in the agriculture, there are certain potential impacts of the wastewater use in agriculture. The anaerobic as well as aerobic digestion methods reduce the BOD (Bio chemical Oxygen Demand) wastes that are the basic constituents of the domestic wastewater. The potential impacts of the use of wastewater in the agriculture are: Crops Treated or untreated waste water is extensively used in agriculture. Results depict that the waste water produces an increased amount of crops and produces a better yield with treated or untreated wastewater. The wastewater is rich in macro nutrients like nitrogen, phosphorus and potassium. However, if the plant is fed with excessive amount if nitrogen, the problems such as delayed ripening of the fruits and loss of fruits are the common damages to the crops in case of utilizing the untreated wastewater. On the other hand, the use of treated wastewater to suit the crop increases the yield. The use of waste water increases the crops but it is important to test the water for the nutrients as some elements and compounds may penetrate into the food chain through crops. Public health Wastewater contain microorganism particularly pathogens, viruses, harmful bacteria, parasitic microorganism. These organisms can be a cause of many diseases. On the other hand, the waste water may contain different parasitic organism or eggs of parasitic organism. These organisms may include tape worms, hookworm, etc. To reduce the impact on the human health, the waste water can be treated thermally or through any other means to reduce the microorganism (Hussain, Raschid, Hanjra, Marikar & van der, 2002). Ecological impact Wastewater drains from the fields and penetrate the local water bodies. Local water bodies can be rivers, streams, etc. The phosphorus in the wastewater particularly ortho-phosphate causes the eutrophication. Eutrophication is the major reason for reducing the absorption of micro nutrients. The biodiversity is thus impacted. The whole process reduces the dissolution of oxygen into the water and impacts the marine biodiversity. The businesses that are associated with the marine biodiversity are also affected. In this manner, the wastewater can impact the whole environment. However, if the water is treated to reduce the ortho phosphate and other harmful compounds that can damage the environment, treated wastewater can be used in agriculture. Groundwater resources Wastewater seeps down to the underground water reservoirs and can contaminate the underground water. Thus, it is important to prevent the wastewater to seep into the ground. This can be done by making the wastewater channels water tight so that water seepage into the can be limited. On the other hand, advanced treatment of biological wastes proposed a method in which the wastewater is pumped into the ground and water is taken from the ground. The microorganisms present in the soil absorb the biological wastes in the water and thus pure water can be attained that is passed through several layers of sediments (Hussain, Raschid, Hanjra, Marikar & van der, 2002). Soil resources Besides having many soil enriching nutrients in the wastewater, untreated wastewater has many other constituents that can pollute the soil. The waste water is also rich in minerals and salts. On the other hand, the higher content of macro nutrients may also damage the condition of the soil. The wastewater is also rich in chemical compounds. All these constituents may degrade the condition of the soil and may damage the condition of the soil. Long termed use of wastewater may produce condition of saline the soil (Hussain, Raschid, Hanjra, Marikar & van der, 2002). Economics of Wastewater Irrigation Economic perspective of wastewater irrigation depends on various factors like pumping costs, land costs, types of corps harvested, use of crops, cost of treatment of wastewater and regulations regarding wastewater use. Low cost methods of wastes disposal and municipal water disposal require larger land areas and long time (Scott, Faruqui & Raschid-Sally, 2004). Some researchers suggest that wastewater should be used to harvest the crops that should be used for extracting the bio-fuels. Bio-fuels are becoming the spreading business in the current world scenario, where petroleum fuel prices are rising day by day. The crops that are produced for the bio-fuels can be harvested directly on untreated wastewater and thus the cost of treating the wastewater can be reduced (Galbraith, 2013). However, this strategy can produce some environmental problems but using a scheme like that used in the hydroponics method can isolate the crop production from the environment. Hydroponics is a method in which plants do not require soil; water remains in direct contact with the roots of the plants. This method saves the water from seeping into the ground and prevents the useful nutrients from being wasted. This method also prevents the nutrients rich water to enter the ecology. Wastewater for Industrial Use Wastewater can be easily be utilized in many industrial application just by filtering the sedimentation and particulates in it. No further treatment is required in some industries. Industrial wastewater is recycled many times without any extended treatment and used again and again in many industries. However, some industries require treated wastewater and some require the water with drinkable quality. Untreated wastewater can be filtered to remove the dirt and solid wastes and can be directly used in industries like power generation units, water cooling and steam generating units. In power generation units, internal combustion engines or steam engines are utilized to generating the mechanical energy that is then converted to the electrical energy through electrical generators. The internal combustion engines require constant cooling to prevent it from overheating and thus damaging the engine (Harrington & Nelson, 2006). Wastewater can be used as the cooling water to cool the internal combustion engine. On the other hand, in the steam turbine, wastewater can be utilized as the cooling agent to convert the steam back to the water. It can be used at any industry that requires cooling. Compressors also require cooling; wastewater can be used as the compressor cooling water. Untreated but filtered wastewater can be used in the boilers to generate steam. The steam is free from any pathogens or any impurity that is present in the untreated wastewater (Patterson, 1985). It can be method to treat the wastewater by distilling the wastewater and collecting the distilled water. Distilled water is safe for drinking or any other use. Using the wastewater for the cooling of the engines and as the cooling water is much cost effective as it require the least amount to filter the water from solid wastes and no treatment in required and thus it is most economically feasible (Munter, 2000). Wastewater that is treated to remove solid wastes, bio-degradable compounds (BOD) and COD can be utilized in the textiles for dying purposes. Dying requires much water in the textile industry and it is better to replace the drinkable water with the treated wastewater for the dying purposes in the textile industry. In the textile treated wastewater can also be utilized for washing the yarn. Similar treated wastewater can also be utilized in laundry for washing the clothes. Food and beverage industry requires the water with the drinkable quality. If there is no option besides using the wastewater to be utilized in the industry, the water should be treated properly and filtered through membrane technology like RO filtration to free the water from any particles and pathogens. Conclusion Wastewater can be utilized in the agriculture as well as in the industry but from the environmental point of view, in agriculture, the wastewater should be properly treated before it is fed to the plants. However, form economic point of view, it can be directly utilized but only from the crops that are not grown as the edible crops. It can be used to harvest the crops that can give high yield of bio-fuels. If the wastewater is treated through anaerobic digestion of biological wastes, it can give biogas and bio-waste that can be used to generate energy for the plant or for the community. In this way, treating the wastewater is economically as well as environmentally feasible in agriculture industry. For the industrial use, wastewater is much effective particularly in the power generation sector to be utilized as the cooling agent. It requires a little filtration to be free from the sedimentation and solid wastes. It can be passed through the engines to be utilized as to cool the engine to protect the vital parts of the engine. In the similar manner, it can be used in the steam generator to act as to reduce the temperature of the steam to convert it back to water. Treated wastewater can be utilized in the textile industry. References Cifuentes, E., Blumenthal, U., Ruiz-Palacios, G., & Bennett, S. (1991). Health impact evaluation of wastewater use in Mexico. Public health reviews, 19(1-4), 243 (Cifuentes, Blumenthal, Ruiz-Palacios & Bennett, 1991, 243) De-Bashan, L. E., & Bashan, Y. (2004). Recent advances in removing phosphorus from wastewater and its future use as fertilizer (1997–2003). Water Research, 38(19), 4222-4246. Drechsel, P., Scott, C. A., Raschid-Sally, L., Redwood, M., & Bahri, A. (2009). Wastewater irrigation and health. Assessing and Mitigating Risk in Low-income Countries. London: Earthscan. Galbraith, K. (2013). The many uses of wastewater. [online] Retrieved from: http://green.blogs.nytimes.com/2008/11/21/the-many-uses-of-wastewater/?_r=1 [Accessed: 25 Dec 2013]. Harrington, W., & Nelson, P. 2006. Public Treatment of Private Waste: Industrial Use of Municipal Wastewater Treatment. Resources for the Future. Hussain, I., Raschid, L., Hanjra, M. A., Marikar, F., & van der Hoek, W. (2002). Wastewater Use in Agriculture. Munter, R. (2000). Industrial Wastewater Treatment. Sustainable Water Management in the Baltic Sea Basin, Book II, Water Use and Management. Patterson, J. W. (1985). Industrial wastewater treatment technology. Pescod, M. B. (1992). Wastewater treatment and use in agriculture. Scott, C. A., Faruqui, N. I., & Raschid-Sally, L. (2004). 1. Wastewater Use in Irrigated Agriculture: Management Challenges in Developing Countries. Tchobanoglous, G., & Burton, F. L. (2003). Wastewater engineering.MANAGEMENT, 7, 1-4. Read More