A Multi Expert Decision Support Tool for the Evaluation of Advanced Wastewater Treatment Trains: A Novel Approach to Improve Urban Sustainability

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Wastewater Treatment (WWT) for water reuse applications has been accepted as a strategic solution in improving water supplies across the globe; however, there are still various challenges that should be overcome. Selection of practical solutions is then required whilst considering technical, environmental, socio-cultural, and financial factors. In this study, a multi expert decision support tool that considers a variety of evaluation criteria is proposed to provide a ranking system for competing advanced WWT technologies in terms of their performance. Two scenarios of water reuse in the contexts of Brazil and Greece are defined, and evaluation is undertaken based on opinions of water reuse experts. The results prove that the tool would successfully facilitate rigorous and methodical analysis in evaluation of WWT technologies for water reuse applications with potential for use under various sets of evaluation criteria, WWT technologies and contexts

Selective and low temperature transition metal intercalation in layered tellurides

Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T2PTe2 (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80?°C for cadmium in Ti2PTe2). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid

Removal of hexavalent chromium of contaminated soil by coupling electrokinetic remediation and permeable reactive biobarriers

PURPOSE: In this study, a novel and ecological alternative have been developed to treat soils contaminated with hexavalent chromium coupling two well-known systems: electrokinetic remediation and permeable reactive biobarriers. The electric field promotes the electromigration of the hexavalent chromium oxyanions towards the anode. The biobarriers were placed before the anode electrode, in order to promote the reduction and retention of the chromium migrating in its direction. Thus, this technology provided a global treatment to soil removal without subsequent treatments of the contaminated effluents. METHODS: The electrokinetic system was coupled with two different permeable reactive biobarriers composed by Arthrobacter viscosus bacteria, supported either in activated carbon or zeolite. An electric field of 10 V was applied and two different treatment times of 9 and 18 days were tested. RESULTS: Removal values of 60% and 79% were obtained when electrokinetic treatment was coupled with zeolite and activated carbon biobarriers, respectively, for a test period of 18 day. The reduction of hexavalent chromium to trivalent chromium was around 45% for both systems. CONCLUSIONS: In this work, two types of biobarriers were efficiently coupled to electrokinetic treatment to decontaminate soil with Cr(VI). Furthermore, the viability of the new coupling technology developed (electrokinetic + biobarriers) to treat low-permeability polluted soils was demonstrated.This work was supported by the Spanish Ministry of Science and Innovation (CTQ2008-03059/PPQ), Xunta de Galicia (08MDS034314PR). The authors are grateful to the Spanish Ministry of Science and Innovation for providing financial support for Marta Pazos under the Ramon y Cajal program and the Fundacao para a Ciencia e Tecnologia, Ministerio da Ciencia e Tecnologia, Portugal through the PhD grant of Bruna Fonseca (SFRH/BD/27780/2006)

Removal Mechanisms of Toluene from Aqueous Solutions by Chitin and Chitosan

Low-cost materials of natural origin such as chitin and chitosan were found to effectively remove toluene from aqueous solutions. Batch adsorption experiments for the removal of toluene (5–200 mg/L) were conducted to obtain the isotherm profile. The effects of various parameters such as initial concentrations, adsorbent dose, and contact time on the removal performance of toluene were evaluated. Chitosan shows better removal efficiency, compared to chitin, both in terms of the level of toluene adsorbed per unit mass of adsorbent and in terms of the adsorption kinetics. Adsorption capacity in the range of 33%–58% efficiency was obtained when the chitosan materials were used. The adsorption data on toluene were found to best fit the Langmuir and Redlich–Peterson isotherm models. The kinetic studies revealed that the adsorption of toluene followed the pseudo-second-order rate model. Overall, the study demonstrated that chitosan is a potential adsorbent for the removal of toluene at concentrations as high as 200 mg/L

Removal Mechanisms of Toluene from Aqueous Solutions by Chitin and Chitosan

Low-cost materials of natural origin such as chitin and chitosan were found to effectively remove toluene from aqueous solutions. Batch adsorption experiments for the removal of toluene (5–200 mg/L) were conducted to obtain the isotherm profile. The effects of various parameters such as initial concentrations, adsorbent dose, and contact time on the removal performance of toluene were evaluated. Chitosan shows better removal efficiency, compared to chitin, both in terms of the level of toluene adsorbed per unit mass of adsorbent and in terms of the adsorption kinetics. Adsorption capacity in the range of 33%–58% efficiency was obtained when the chitosan materials were used. The adsorption data on toluene were found to best fit the Langmuir and Redlich–Peterson isotherm models. The kinetic studies revealed that the adsorption of toluene followed the pseudo-second-order rate model. Overall, the study demonstrated that chitosan is a potential adsorbent for the removal of toluene at concentrations as high as 200 mg/L

The potential of wastewater reuse for agricultural irrigation in Libya: Tobruk as a case study

© 2015 global NEST.The aim of this paper is to highlight the way towards the exploitation of treated wastewater for food crops production in order to cope with the acute water scarcity and its hazardous consequences. Reclaimed water reuse has not been practiced in Tobruk, and hence, lack of relevant data and information was the major difficulty in carrying out this research. The existing sewage treatment plant in Tobruk city produces about 7,000 cubic meters per day of suitable effluent for agricultural irrigation and safe discharge. This proportion is worth twice as much as the water being currently used for irrigation. Therefore, with proper planning and management, treated wastewater reuse schemes, in addition to their economical and environmental benefits, can be an efficient mechanism to cope with water shortage and reducing the high burden placed on the desalination plant. Wastewater reuse is considered as a reliable, secure, and drought-resistant water source. Owing to the lack of disinfection processes and routinely monitoring data, there is uncertainty concerning the microbiological safety and quality of the treated effluent. Public perception might be the major challenge facing the planning for a reuse scheme as 51 % of the population of Tobruk have shown their reluctance to consume food crops irrigated with treated wastewater. Nonetheless, public attitudes can be fostered by awareness through the media as some people, when the issue was discussed, have shown a positive response. In fact their main concerns were related to public health safety and potential negative environmental impacts which can be addressed through good planning and prudent management

The potential of wastewater reuse for agricultural irrigation in Libya: Tobruk as a case study

© 2015 global NEST.The aim of this paper is to highlight the way towards the exploitation of treated wastewater for food crops production in order to cope with the acute water scarcity and its hazardous consequences. Reclaimed water reuse has not been practiced in Tobruk, and hence, lack of relevant data and information was the major difficulty in carrying out this research. The existing sewage treatment plant in Tobruk city produces about 7,000 cubic meters per day of suitable effluent for agricultural irrigation and safe discharge. This proportion is worth twice as much as the water being currently used for irrigation. Therefore, with proper planning and management, treated wastewater reuse schemes, in addition to their economical and environmental benefits, can be an efficient mechanism to cope with water shortage and reducing the high burden placed on the desalination plant. Wastewater reuse is considered as a reliable, secure, and drought-resistant water source. Owing to the lack of disinfection processes and routinely monitoring data, there is uncertainty concerning the microbiological safety and quality of the treated effluent. Public perception might be the major challenge facing the planning for a reuse scheme as 51 % of the population of Tobruk have shown their reluctance to consume food crops irrigated with treated wastewater. Nonetheless, public attitudes can be fostered by awareness through the media as some people, when the issue was discussed, have shown a positive response. In fact their main concerns were related to public health safety and potential negative environmental impacts which can be addressed through good planning and prudent management