Treated Wastewater Usage in Agriculture

Agriculture is the art and science of growing plants and livestock. Agricultural wastewater treatment is therefore primarily a management task used on farms to control pollution from surface runoff that may be contaminated by chemicals such as fertilizers, pesticides and even irrigation water. Reusing wastewater helps conserve freshwater while also reducing environmental impact and utility costs. We've all heard the saying, "Food grows where water flows." While fresh water content has been a recent challenge for the agricultural sector, there is a need for recycled water. This paper considers the use of recycled wastewater in Agriculture and investigate its corresponding risks and benefits to humans and the environment.

Wastewater use in agriculture involves the further use of recycled wastewater for the environment and crop irrigation. The use of this treated wastewater in agriculture benefits human health, the economy, and even the environment. This use presents an alternative practice that is being adopted in different areas affected by water shortages and even the growing urban areas faced with limited sources of water. The use of recycled wastewater has been able to impact the agricultural sector in different ways.

The decrease in freshwater use is considered to be the main advantage of wastewater use. In many agricultural farms, the availability of freshwater for their irrigation purposes has been a challenge. Therefore, it is necessary to come up with ideas to curb the problem being experienced. Due to the availability of recycled water, different farms have been able to access water for their crop irrigation. This in return helps in increasing the agricultural production in this particular area thus contributing to food safety.

In the local areas, another benefit associated with agricultural reuse of wastewater is the act of avoiding the cost incurred in extracting groundwater resources. It is worth to note that extraction of groundwater takes up to 65 percent of the irrigation activities, therefore, having to use recycled wastewater for crop irrigation and even other agricultural activities save the irrigation processes a great deal.

Also, the reuse of wastewater for the agricultural activities is important because it allows savings on other crop growing expenses such as buying of fertilizers. The reuse of wastewater in crop irrigation provides the crops with the necessary nutrients. This increases the production levels of the agricultural products. Scientifically the reuse of wastewater or recycled water provides a closed and environmental friendly nutrient cycle that avoids the indirect return of micro and macro elements of water bodies. Wastewater can be considered as a potential source of macro and micronutrients depending on the nutrients available. Therefore, the improvement in yielding of crops is as a result of using wastewater or recycled water for the irrigation purposes.

Another benefit of treated wastewater use is the prevention of water pollution in Agriculture. Since water pollution comes from the discharge of wastewater from factories and all other industrial departments. Recycling this water would mainly improve the source quality of receiving water bodies (Wang, X.C. (2014)). Moreover, due to the availability of recycled water or treated wastewater most of the groundwater reservoirs preserved with high-quality water.

The Increase use of treated wastewater or recycled water has posted a great benefit to the environment since it has contributed to the installation and optimization of treatment facilities which produce desired product quality for the irrigation purposes. Thus, this leads to a tremendous economic benefit to the sanitation projects in the agricultural sector. To fulfill the agricultural reuse objective in areas where both climatic and geographic characteristics allow low-cost wastewater treatment systems certain technological options are used.

Treated wastewater also benefits the agricultural sector by liberating capital resources through the payment of economic instruments. Wastewater reuse benefits the economy by evaluating the treated water discharged for human consumption which is considered to be the highest priority. Moreover, in some countries wastewater reuse also contributes to the reduction of costs incurred by the municipal in searching for water sources.

Apart from the numerous benefits incurred on the use of treated wastewater use in agricultural products. The extensive use of recycled wastewater has its disadvantages. Since treated wastewater has nutrients that are good for the growing of crops, some agricultural farms may decide to use additional chemicals such as pesticides and herbicides which are applied to the lands to control pests that may disrupt crop production. Soil contamination, therefore, occurs when pesticides persist and accumulate in the soils. Due to the extensive use of these chemicals in the soil, most of the microbial process is altered and also cause toxicity to the soil organisms. The result to all leads to lower crop yields.

In addition to the use of treated or not treated wastewater in agriculture is not exempted from adverse effects to the soil. The possible scientific literature includes evidence of alterations in the physiochemical parameters of the soil. (Sweetman A.(2015)) The physiochemical parameters of the soil are mainly altered by an increase in microbial activity caused by the treated wastewater use in agriculture. Due to the alteration of the physiochemical parameters of the soil and even the soil affects the fertility and productivity of that particular soil thus destroying the soil sustainability from the inadequate irrigation with wastewater.

Research studies have shown the variations in the soil pH resulting from the irrigation enhanced by the municipals wastewater treatment systems at different treatment levels. The change in the pH is attributed to three factors which are the period of irrigation taken, the ultimate soil texture and finally the type of soil cover. The changes in the soil pH mostly influence the availability of nutrients in the soil and even the mineralization of organic matter.

Moreover, the main function of the organic matter produced is of soil structure and even for the storage of nutrients. Hence, the organic matter content produced is mainly responsible for the capacity of the soil to retain water. The agricultural reuse of the treated water may at times damage the organic matter of the soil hence destroying the capacity of the soil to retain water.

Due to the presence of pathogens and toxic chemicals in the treated wastewater, irrigations with this water pose a great risk to the human health. This risk occurs to humans when or via the consumption of the pathogenic microorganisms and harmful organic chemicals. Mostly the highly affected people are the workers and their families, consumers of crops, meat and even milk also those living nearby these irrigated areas are also affected. The process involved in the treatment of wastewater reduces the availability of this pathogenic microorganisms content, but unfortunately, it does not eliminate all of them. To eliminate the pathogenic microorganisms, an expensive process is usually required. Most local areas may not afford this process hence end up omitting the process while treating their wastewater.

Also, another potential health threat may be caused by the cross-connection between the treated wastewater and fresh water piping systems. This scenario poses a great risk since the wastewater pipes may insert chemical contamination directly to the fresh water piping systems. In such an unknown risk it is impossible to avoid the human health being affected hence it is always important to avoid all the possible known or unknown risks while dealing with water.

Apart from the human risks treated wastewater also poses a great challenge to the environment. Irrigations with treated wastewater cause land salinity, land sealing, and sodium accumulation. Extensive use of this treated wastewater will lead to an increase in the salinity and land sealing levels. Studies have shown that high salinity levels deteriorate the soil structures and also decreases the soil permeability which in return leads to a reduction in crop yielding because of the toxic and osmotic effects.

Treated wastewater also affects the environment by transferring heavy metals to the fertile grounds which in return affects flora and fauna of the soils causing contamination of the crops. Groundwater reservoirs are also affected by the use of treated wastewater since wastewater enhances excess salts and nutrients on the root zones of the plants which damage the water storages.

For treated wastewater to be regarded as ready for consumption, it has to be sufficiently treated to a certain quality (Dalwani, R. (2004)) Water that is not well treated may ultimately cause harmful effects to the human health.Drinking this water or even being exposed to the recycled water with disease-causing organisms or any other contaminants related to treated wastewater leads to incurable diseases. Hence, even though treating wastewater is costly and requires a highly sustainable approach it is important to install the necessary systems required for its treatment to avoid all the possible negative effects.

Globally, agriculture is perceived to be a major consumer of wastewater. To ensure food safety and even preserve natural water bodies there is a need for the search of an alternative irrigation source. Treated wastewater is used as the alternative form of irrigation source is considered to be the best strategy taken for prevention of water pollution. It is mainly gaining popularity worldwide especially in countries being faced by water shortages. Although there are extensive advantages to the use of treated wastewater to the agricultural sector, the risks involved are also vital and if not attended to may cause a very real public health. The risks of reusing wastewater range from the physiochemical properties of soil and also the microbiological properties to the effects to the human health.

In areas with unfriendly economic conditions, any alternative form of irrigation such as the use of treated wastewater should be well analyzed, and even it is very necessary to communicate about both the positive and negative impacts of this new practice. For proper implementation of the agricultural reuse, it is important to evaluate the microbiological risk referring to the concentration of helminths. The lack of an actual evaluation has promoted the use of raw sewage water which is influenced by the lack of norms and standards in some countries which do not adhere to any global guidelines given. To ensure the safe use of treated wastewater it is important to improve the techniques of detecting helminths.

References

Singh, K,P.,Mohan,D.,Sinha,S., &Dalwani,R.(2004).Impact assessment of treated/untreated wastewater toxicants discharged by sewage treatment plants on health, agricultural and environment quality in the wastewater disposal area. Chemosphere, 55(2), 227-255.

Lu, Y.,Song,S.,Wang,R.,Liu Z., Meng, J.,Sweetman,A.J.,…&Wang,T.(2015).Impact of soil and water pollution on food safety and health risks in China. Environment international, 77, 5-15.

Luo, Y.,Guo,W.,Ngo,H. H.,Nghiem, L.D.,Hai,,F.I Zhang,J.,…&Wang, X.C.(2014).A review on the occurrence of micro pollutants in the aquatic environment and their fate and removal during wastewater treatment. Science of the Total Environment, 473,619-641