Wastewater reuse in Jordan: Present status and future plans

Wastewater in Jordan can be characterized as very strong with high salinity and insignificant heavy metals and toxic organic compounds. For the past two decades Jordan has relied on waste stabilization ponds (WSP) to treat wastewater for reuse in agriculture. This has exacerbated the salinity problem due to the high evaporation rates in such plants. Effluent from these plants are mixed with freshwater resources and stored before being used in agriculture in the Jordan Valley. Yield potential of most crops grown in the Jordan Valley lie between 50–80% if effluent alone is used for irrigation. The high chloride concentration may be detrimental to certain crops, especially beans and in case sprinkler irrigation is used. WSP are being replaced by conventional activated sludge and extended aeration plants, with the sites of the ponds being used as maturation ponds (MP). Nitrification and denitrification and in some cases phosphorous removal is and will be practiced. In some plants, sand filtration is planned either in lieu of MP or in addition to MP. Effluent quality of some of the newly operated plants is very high. In addition, the volume of treated wastewater will increase as a result of high population growth and increased sewered areas. These two factors provide opportunities for new water reuse applications. These include groundwater recharge, industrial cooling, and even municipal reuse.

A number of water quality parameters may affect the use of reclaimed water for irrigation and the yield of irrigated crops in the Jordan valley. The main parameters are high salinity and high chloride concentrations. These can reduce the yield of some sensitive crops to about 60% or even less, if no irrigation management practices are undertaken. As the volume of reclaimed water is to increase in the future, more water for soil leaching should be available. If saline water is diverted from the sewer system, along with the replacement of waste stabilization ponds, which increases salinity through the high evaporation rates, this may help alleviate some of these problems. The expected good quality effluent of the new wastewater treatment plants has made it possible to explore new reuse applications in Jordan such as industrial cooling, groundwater recharge, and even municipal use. Industrial cooling is possible, and in fact the reclaimed water was found of higher quality than the water being used in a number of large industrial applications. Phosphorous removal is however necessary. Groundwater recharge may be possible as a storage and quality improvement method, as surface storage methods are prone to a number of problems such as eutrophication and evaporation. For sustainable reuse of wastewater, some steps have to be taken. Industrial discharges in the future may increase and therefore have to be monitored. High salinity wastewaters have to be diverted from sewer system, and standards and regulations have to be adjusted to cope with new pollutants and new applications.