Efficient water resources management in Cr(VI) impacted water bodies

The holistic approach of the Driver-Pressure-State-Impact-Response (DPSIR) analytical framework in combination with Geographical Information Systems was applied to selected Cr(VI) impacted groundwater bodies. For the characterization of water-quality “state” 157 samples including field blanks were collected during the wet and dry seasons of 2017 and 2018 and several physicochemical parameters were determined. In Loutraki area, Cr(VI) in groundwater ranged from 12 to 62 μg/L while NO3 and Cl maximum values were 157mg/L and 218mg/L respectively. Very high concentrations of Cr(VI) (up to 430μg/L), NO3 (up to 245mg/L) and Cl (up to 1039mg/L) were measured in the Schinos alluvial aquifer. Additionally, Cr(VI) up to 131μg/L and NO3 up to 156mg/L were identified in the groundwater ofThiva agricultural area. In C. Evia, Cr(VI) was up to 96μg/L while NO3 and Cl concentrations were also high reaching 362mg/L and 793mg/L respectively. Finally, the highest Cr(VI) concentrations (up to 11.7 mg/L) were measured in Oinofyta area. The main identified pressures are: i) NO3 pollution due to intensive agriculture and urban waste disposal, ii) sea water intrusion due to overpumping and iii) Cr(VI) contamination due to both natural processes and industrial activities (clearly in the case of Oinofyta). In many cases, Cr(VI), NO3 and Cl are above the upper drinking water threshold values of the European Directive 98/83/EC.

This study involved the synthesis of kaolin-supported nano zero valent iron (K-nZVI) and the evaluation of its performance for the removal of chromates and nickel from contaminated waters. K-nZVI was prepared by mixing a kaolin sample with a FeCl3 solution, followed by the addition of sodium borohydride for the reduction of Fe(III) to the zero valent state. The effectiveness of kaolin supported nZVI for Cr(VI) and Ni removal was evaluated by conducting batch experiments. The investigated parameters included the amount of K-nZVI per solution volume, the concentration of contaminants and the effect of pH. K-nZVI was found to be more efficient for the treatment of Cr(VI) contaminated waters than for the removal of Ni. Using 1 gram of K-nZVI per liter of solution, it was possible to reduce 20 mg/L of Cr(VI) to less than 5 mg/L within 3 hours. Starting with the same concentration of Ni, i.e.20 mg/L, the final concentration after 3 hours was aproximately 17 mg/L at pH 5.6, and dropped to 10 mg/L when the pH of the suspension was regulated to the value of 7.5. The results suggest the K-nZVI has a rather limited efficiency for Ni removal.

Stakeholder participation in prioritization of water supply and demand was developed to assist water resource entities and water users on decision making when coping with water scarcity, climate change and contaminated water in Zarqa River Basin, Jordan. The basin was selected for CrITERIA project to represent a case study of semi-arid area in the Mediterranean. The paper demonstrates a participatory approach of integrating stakeholders’ experience and their active involvement in water management. Issues related to prioritization of water demand were identified, and the opinions of stakeholder were ranked according to their role in securing supply and improving supply reliability. The most important issues were ranked according to number of opinions out of the total. Findings showed that water management issues was the major issue in the basin and represents 86% of the stakeholders opinions, followed by water supply as 82% to less extent by water demand as 77% and quality as 68%. Most of the stakeholders agreed that management issues are the major cause of water scarcity. Like expected, water problems in Jordan are 50% associated with poor management and 50% due to water scarcity.