Introduction
The arid and semi-arid areas have been experiencing serious food problems because of the poor performance of agricultural practices. However, the land is increasingly becoming scarce. Irrigation has been found to be the most appropriate way of reclaiming land in arid areas for agriculture.
Given that in these arid areas water is a rare commodity, recycling of wastewaters has been considered as one of the ways that can be used to increase the amount of water for irrigation for such regions. According to Nasr, Doma, and Nassar (2009), wastewater that has been used domestically can be recycled for the purpose of being used in irrigation.
This scholar says that although some harmful substances can be found in such water, it is becoming evident that some parts of these arid areas will be forced to use wastewater for agriculture. It is necessary to treat such water before it can be used for irrigation. When used responsibly, the problem of food insecurity in such regions can be eliminated. The paper is focused on recycling wastewater for agricultural use in arid and semi-arid areas.
Background
Wastewater
According to Vasanthavigar, Srinivasamoorthy and Prasanna (2012), waste water refers to water that has been used domestically or in the industrial sector, and therefore, is released as waste.
In major cities, the volume of wastewater can be considerably high because of the number of companies, and the population staying in such cities. It is important to note that industrial waste water may not be recycled easily because of the heavy presence of chemicals they have. This means that it is the domestic wastewater that is always recycled for the purpose of irrigation in arid and semi arid lands.
Recycling
Recycling refers to the process of reusing waste water for various purposes instead of disposing it. Recycling of wastewater is a comprehensive process that entails obtaining the wastewater and subjecting it to some treatment before releasing it for irrigation purposes. The chart below is a representation of the process that takes place when recycling wastewater.
Chart 1: Recycling of Wastewater
Source: (Hernandez & Uddameri, 2010)
Increasing Water Scarcity
There is a decreasing quantity and quality of water in the Thirumanimuttar sub-basin located in the southern part of India. A study carried out on this basin revealed that the poor water quality has adversely affected crop yields. It is apparent that even ground water may be adversely affected by human pollution of the immediate environment.
As a result, there is need to recycle ground water through wastewater treatment process (Vasanthavigar, Srinivasamoorthy & Prasanna, 2012). Needless to say, industrial activities have worsened the state of water purity due to the discharge of effluents into water sources, making clean water even scarcer in some regions.
Increasing Population
There is a steady rise in the world’s population, and this is exerting a lot of pressure on the world’s water sources. Fatta, Salem, Mountadar, Assobhei and Loizidou (2004) say, “In absolute terms the urban population of all Mediterranean countries- 274.5 million in 2000- will reach 379 million by 2025” (227). This population increase has been more rapid in the urban centers than it is in the rural setting. This means that a higher percentage of wastewater comes from urban centers. This water should be recycled for use in irrigation.
Waste Water as a Resource
Wastewater has been considered an important resource that can be used in irrigation in arid and semi arid areas. This water can be treated in order to eliminate harmful substances before being released into farms. It is important to note that some ground water can be considered wastes, especially those that have minerals that are harmful to human being and plants.
Such ground water can be treated to increase their suitability for agriculture. Nagarajan, Rajmohan, Mahendran and Senthamilkumar (2010) say, “Irrigational suitability of groundwater in the study region was evaluated, and results suggest that 20% samples are not fit for irrigation” (289).
This type of water supply has been instrumental in regions where surface water is scarce. The two most important sources of ground water in this study were the boreholes and dug wells. From the analyses, the researchers found out that ground water may contain a lot of chemical wastes and therefore may require some form of treatment before it is eventually used for agricultural purposes.
Problems
Treatment
Treatment of wastewater is important before it can be used for agricultural purposes. According to Nagarajan, Rajmohan, Mahendran & Senthamilkumar (2010), water treatment may be considered an expensive process, but it remains one of the best ways of recycling wastewaters to be used for irrigation in arid areas. The scholars argue that it is important for the concerned bodies to develop cheaper methods of recycling this water in order to make it a more effective way of obtaining water for irrigation.
Risks of wastewater use in agriculture
The sustainability of the environment is critically affected by water quality degradation. However, recent research studies have demonstrated that point and diffuse pollution of water sources may indeed assist in sustaining the immediate environment. Lam, Schmalz and Fohrer (2011) are quite categorical that the best management practices such as recycling and treatment of polluted water sources can be instrumental in the field of agriculture especially when it comes to the issue of wastewater management.
Environmental risks
Some scholars have warned that use of wastewater that has not been treated may pose some environmental risks. Wastewater is not safe for use without treatment because some its elements may be destructive to plants. When such plants absorb these substances, it is likely that they may be consumed human beings, a fact that may have negative health consequences on them.
Solution
Building a sewer system and sewage treatment works
One of the best solutions when recycling wastewater for agricultural use would be to build a sewer system and sewage treatment works. Fayza, Hala and Nassar (2009) say, “The anaerobic baffled reactor (ABR) maintains a high void volume without the need for expensive filter media and has a simple design with no special gas collection or sludge separation systems” (270). These scholars emphasize on the use of modern technologies when developing the sewer systems and sewage treatment works.
Smart design
It is necessary to come up with designs that are sensitive to costs and efficiency of the system. As mentioned above, this can only be achieved by using some of the modern technologies. The design must be that which will save time, cost less, and minimize loss of water that has been purified. This means that the efficiency of the system must be smart.
Environment control
When recycling water for agricultural processes, it is necessary to ensure that the process does not subject the environment to any form of risks from the pollutants in water. The process of treating the water should be environmentally friendly. The focus should always be on producing water that is safe to the environment, especially the living organisms.
Suggestions
Use recycling wastewater in university’s campus
One of the suggestions that have been floated is that recycling of wastewater should be done at university campuses. Alexakis, Gotsis, and Giakoumakis (2012) say that this is not only recommended because of the large population that can take part in the process, but also because it will enhance further research in this area. This may help advance knowledge on how to recycle waste water
Costing
Costing is another factor that has been considered as an issue when recycling waste water. It is necessary to ensure that the costs of such processes are regulated as much as possible. Using modern technologies may help in the reduction of this cost. This will make this process very attractive to the middle class and the poor members of the society. It will encourage more people to embrace the re-use of wastewater in agriculture.
Conclusion
Recycling of wastewater is one of the best ways of combating the problem of scarcity of water for irrigation in arid and semi-arid areas. It has gained popularity in parts of Asia and Africa in the recent past. Wastewater should be treated before eventually being channeled for agricultural use. It is important for the relevant authorities to come up with ways of lowering the cost of recycling wastewater to make this process more popular among a wider population.
References
Alexakis, D., Gotsis, D., & Giakoumakis, S. (2012). Assessment of drainage water quality in pre- and post-irrigation seasons for supplemental irrigation use. Environmental Monitoring and Assessment, 184(8), 5051-5063.
Fatta, D., Salem, Z., Mountadar, M., Assobhei, O., & Loizidou, M. (2004). Urban wastewater treatment and reclamation for agricultural irrigation: The situation in morocco and palestine. Environmentalist, 24(4), 227-236.
Fayza, A., Hala, S., & Nassar, F. (2009). Treatment of domestic wastewater using an anaerobic baffled reactor followed by a duckweed pond for agricultural purposes. Environmentalist, 29(8), 270–279.
Hernandez, E. A., & Uddameri, V. (2010). Selecting agricultural best management practices for water conservation and quality improvements using atanassov’s intuitionistic fuzzy sets. Water Resources Management, 24(15), 4589-4612.
Lam, Q. D., Schmalz, B., & Fohrer, N. (2011). The impact of agricultural best management practices on water quality in a north german lowland catchment. Environmental Monitoring and Assessment, 183(1-4), 351-379.
Nagarajan, R., Rajmohan, N., Mahendran, U., & Senthamilkumar, S. (2010). Evaluation of groundwater quality and its suitability for drinking and agricultural use in thanjavur city, tamil nadu, india. Environmental Monitoring and Assessment, 171(1-4), 289-308.
Nasr, F. A., Doma, H. S., & Nassar, H. F. (2009). Treatment of domestic wastewater using an anaerobic baffled reactor followed by a duckweed pond for agricultural purposes. Environmentalist, 29(3), 270-279.
Vasanthavigar, M., Srinivasamoorthy, K., & Prasanna, M. V. (2012). Evaluation of groundwater suitability for domestic, irrigational, and industrial purposes: A case study from thirumanimuttar river basin, tamilnadu, india. Environmental Monitoring and Assessment, 184(1), 405-420.