GRM 2010 GRM 2011

Abstract Details

Family Name:
First Name:
Saif Ali
Title of Paper:
Opportunities and Challenges of Using Treated Wastewater in Agriculture
Paper Proposal Text :
The increase of the world population and the limitation of water in most of the countries, led to over-pumping of traditional water resources especially the groundwater used in agriculture. During the last two decades, the reuse of treated wastewater in agriculture had been increased enormously due to the increase of food demand and agricultural areas.
Agriculture is using between 60-90% of surface and groundwater. The shortage of water could be partially overcome by identifying, this new water sources (TWW). Irrigation for landscaping and golf courses is on the rise in member countries of the Gulf Cooperation Council (GCC). TWW can be used for irrigation under controlled conditions to minimise health risks arising from pathogenic and toxic pollution of the agricultural produce, soils, surface and groundwater. Treated wastewater reuse is believed to be one potential intervention strategy for developing nonconventional water resources. Reuse of reclaimed (treated) wastewater for irrigation and other purposes could contribute considerably to the reduction of ‘water stress’ and ‘water scarcity’ in Arab countries.
This paper will highlight the factors that need to be considered when using treated wastewater in agriculture especially the reuse crop production, in addition to the main challenges and constraints facing the developing countries of treated wastewater reuse in agricultural production.
It is a major challenge to optimize the benefits of treated wastewater as a resource of both the water and the nutrients it contains, and to minimize the negative impacts of its use on human health. Several studies claim that the optimal wastewater treatment level is affected by costs, hazards and benefits. So, lowering the wastewater treatment level decreases fertilization costs because of the increased levels of available nutrients left in the water, and irrigation costs decrease if water prices reflect the lower treatment costs. Agricultural yields and prices may decrease according to differences between levels of nutrients needed by crops and those available in wastewater. Different studies showed an increase of both the quantity and the quality of crops irrigated with treated wastewater. Although, the acceptance of treated wastewater has begin to increase among the farmers in most of GCC countries, the farmers in other Arab countries like Jordan, Tunisia and Syria are using treated wastewater for irrigation of almost all food crops. The studies showed significant benefits from using TWW and low impact in crop irrigation, still the challenges are present concerning the utilization. The challenges could form barriers in using TWW for crops irrigation. The constraints towards maximum use of TWW can be classified as economical, social and environmental. The cost of water has to be acceptable to farmers. If farmers found free source of water they will not go for TWW. The other challenge is the transportation cost of TWW from Sewage Treatment Plants to agricultural areas could be another economical constraint, since most of big STPs are located in the cities where the concentration of people is dense. Social issues play a significant role in water reuse initiatives and should be adequately addressed with adequate political accompanied by awareness programs to overcome cultural, religious and social objections. Acceptance of farmers, retailers and consumers is the most sensitive and important issue. Farmers are not going to reuse water, if their product cannot be sold. Consumers will not buy products where TWW was used unless it is proven to be safe. From the environmental aspect there are potentially positive and negative impacts that should be considered. Presence of pathogens in TWW, chemical contaminants or heavy metals because of insufficient treatment could form a critical constraint towards efficient reuse in crop production.
International guidelines for use and quality standards of wastewater in agriculture exist to mitigate those impacts. The quality of treated wastewater is typically defined in terms of its regulations set. These regulations define wastewater treatment levels and allow uses for the reclaimed water produced. When considered for use as irrigation water, the actual quality of treated wastewater ranges from totally unsuitable to ideally suitable, with most sources falling somewhere in between these extremes.
The above mentioned constraints could be mitigated or overcome by certain specific practices. Treated wastewater must only be reused for the uses for which permit was issued. Quality monitoring and process controls should be supported and strictly applied. When TWW quality does not meet the fixed standards and regulations then reuse must cease. Surface or subsurface (not sprinkler) irrigation should take place in all type of crops cultivation. The routine inspections of wastewater facilities, including facilities located on the property of end users should be practiced.
In conclusion, TWW is proved to be a very promising source of water for irrigation for crop cultivation. Several studies were conducted and recommended the reuse of TWW in agriculture. They highlight the impacts of TWW on agricultural production. However, some constraints have been observed. These are related to economical, environmental and social issues. These constraints could be overcome by following certain practices and proper governmental policies and regulations.