Greywater (GW) treatment by the electrocoagulation (EC) technique alone might not meet the required standards in terms of pollutant removal, specifically when GW contains high loads of pollutants. In this preliminary study, a sand filtration (SF) unit was integrated with the EC technique as a pretreatment step to enhance the EC process for treating high-loaded GW. Three different voltage gradients were investigated (5 V/cm, 10 V/cm, and 15 V/cm) in the EC unit. The results demonstrated that the pretreatment SF step can contribute significantly to reducing pollutant concentrations in the greywater to be treated by EC. In terms of physical impurities, the results showed that the SF pretreatment step reduced the turbidity and the color of the treated GW by 28.4%, and 9.4%, respectively. The COD concentration was reduced by 25.5% by the SF step, which allowed a reduction of EC steady state time in the EC unit from 45 min to 30 min at an applied voltage of 15 V/cm. In addition, a high COD removal rate of 87.8% from high-load greywater was achieved with an energy consumption of only 4.11 kWh/m³ in comparison with 6.21 kWh/m³ without the SF step, which is equivalent to a 34% saving in energy consumption.

Climate change has become an unequivocal issue; changing precipitation patterns and climate variability will have disastrous impacts on the fragile agricultural land resources of arid regions. Farmers, equipped with indigenous knowledge and readily available resources, are the most direct stakeholder interacting with agricultural lands; examining farmers’ capacity to successfully implement farm-level adaptive measures is a pressing matter. This paper provides an overview on various agricultural measures for climate change adaptation in arid regions and discusses some major relevant constrains and the extent of farmers’ capabilities to implement such strategies. Various techniques such as shifting sowing dates, conservation agriculture, and rainwater harvesting have shown potential to serve as adaptive strategies. These can help reduce crop failure risks, improve soil moisture conservation and increase water availability for crops, and could help adapt to precipitation variability in arid regions. However there is strong evidence that many farmers in arid regions may not be able to implement such strategies successfully as adaptive measures and there is no clear evidence that climate variability is currently less of a risk with existence of such measures. This can be attributed to the various constraints such as the need for reliable access to resources, climatic data, and research output by farmers for successful implementation. These constraints could be circumvented by institutional-level measures such as agricultural subsidies, relevant and dynamic policies, and programs. Overwhelming evidence suggests that this is only possible by involvement of various stakeholders in the planning process such as researchers, farmers and the private sector.