A kinetic modeling study of phosphate adsorption onto Phoenix dactylifera L. date palm fibers in batch mode

AbstractThe removal of phosphates from aqueous solutions by adsorption onto date palm fibers (DPF) has been studied in batch mode. The aim of this study was to understand the mechanisms that govern phosphate sorption and find an appropriate model for the kinetics of removal. In order to investigate the mechanism of sorption and potential rate controlling steps, pseudo first-order, pseudo second-order, intra-particle diffusion and the Elovich equations have been used to test experimental data. Kinetic analysis of the four models has been carried out for initial phosphate concentration in the range of 30–110mg/L. The rate constants for the four models have been determined and the correlation coefficients have been calculated in order to assess which model provides the best fit predicted data with experimental results. Seven statistical functions were used to estimate the error deviations between experimental and theoretically predicted kinetic adsorption values, including the average relative error deviation (ARED), Marquardt’s percent standard error deviation (MPSED), the hybrid fractional error function (HYBRID), the sum of the squares of the errors (SSE) and three alternative statistical functions, including the Chi-square test, the F-test and Student’s T-test. The results showed that, both Elovich equation and pseudo second-order equation provide the best fit to experimental data for different initial phosphate concentrations

Élimination de la turbidité par oxygénation et filtration successives des eaux de la station de Sfax (Sud de la Tunisie)

La possibilité d’éliminer la turbidité d’origine minérale (liée notamment à la présence de fer ferrique), en utilisant un système d’oxygénation suivi de la filtration, a été étudiée à l’échelle du laboratoire dans le but de minimiser l’effet protecteur de ce paramètre contre la désinfection de ces eaux. Différents tests ont été effectués à partir d’échantillons d’eau de forage (forage PK 10, forage PK 11 et forage PK 14) et d’échantillons mixtes (mélange PK 10, mélange PK 11 et mélange PK 14) représentatifs de l’eau brute utilisée à la station de Sfax pour la production d’eau potable. L’efficacité de ce traitement a été évaluée par la mesure de la turbidité, de la concentration totale de fer en solution et du chlore avant et après traitement. Les meilleurs résultats ont été obtenus lors de l’oxygénation de l’eau du forage PK 14 pendant 90 minutes suivie d’une double filtration. Ce mode de traitement a permis un excellent abattement de la turbidité (95,3 %). Une importante déferrisation des eaux PK 14 (81,9 %) a été obtenue par un traitement d’oxygénation suivi d’une simple filtration.The possibility of eliminating turbidity of mineral origin (related in particular to the presence of ferric iron), by using a system of oxygenation followed by filtration, was studied at the laboratory scale with an aim of minimizing the antagonistic effect of the turbidity against the disinfection of water. Various tests were carried out on bore-hole water samples (Bore PK10, Bore PK11, and Bore PK14) and on mixed samples (Mixture PK10, Mixture PK11 and Mixture PK14) representative of raw water used at the Sfax water treatment plant for the production of drinking water. The effectiveness of this treatment was evaluated by the measurement of turbidity, the total iron concentration in solution and the chlorine concentration before and after treatment. The best results were obtained for oxygenation (during 90 min) followed by a double filtration treatment process applied to the PK14 bore-hole water. This treatment process resulted in an excellent reduction in turbidity (95%). Significant iron removal from the PK14 water was obtained by oxygenation followed by a simple filtration treatment process (82%)

Involvement of citizens in the measurements of water salinity using test kits in the Medjerda watershed (Northern Tunisia)

Water resources in Africa are subjected to many pressures related to urban growth, agricultural expansion, and climate change (Bahri et al., 2016). These pressures jeopardise reaching the UN-Sustainable Development Goal 6 (SDG6). Efficient monitoring of water systems is pivotal for designing efficient water management strategies that alleviates aforementioned pressures (Mutambara et al., 2016). Yet, the water monitoring capacity in Africa is often very poor, in particular for Water Quality Monitoring (WQM). Citizen Science (CS) based WQM is nowadays proposed as an innovative approach to strengthen the WQM capacity (Fehri et al., 2020; Njue et al., 2019; Jollymore et al., 2017). The concept of CS is based on the potential social benefits of engaging, collaborating and actively involving citizens in data collection and knowledge generation. Yet, the quality of CS-based WQM is different as compared to reference WQM. CS-based WQM programmes need therefore to be thoroughly validated. The main objective of this study is to assess the quality of a CSbased WQM program for the Medjerda river in Tunisia

Participatory water quality monitoring

Pressures on water resources jeopardise reaching the UN-Sustainable Development Goal 6 (SDG6) for clean water and sanitation and Goal 13 (SDG13) for taking urgent action to combat climate change and its impacts. Water resources management in Tunisia has been repeatedly confronted with the impact of climate change. The water monitoring capacity in Tunisia is often poor as a component of Water Quality Management. Citizen Science (CS) has been evolving last years as an innovative approach of environmental monitoring and capacity building of hydrosystems using smart and low cost-effective technologies as tools for data collection (Fehri et al., 2020a; Fehri et al., 2020b; Chaabane et al., 2021; Fehri, 2021; Slama, 2021). This factsheet is addressed to decision makers to involve Citizens in Water Quality Monitoring

Assessment of Citizen's Measurements Using Test Strips for Water Quality in Medjerda Watershed (Northern Tunisia)

Water resources in Africa are subjected to many pressures related to urban growth and agricultural expansions which will be exarcebated by climate change. These pressures jeopardise achieving the UN-Sustainable Development Goal 6 (SDG6). Water resources in Africa are subjected to many pressures related to urban growth, agricultural expansion, and climate change (Bahri et al., 2016). These pressures jeopardise reaching the UN-Sustainable Development Goal 6 (SDG6). Efficient monitoring of water systems is pivotal for designing efficient water management strategies that alleviates aforementioned pressures (Mutambara et al., 2016). Yet, the water monitoring capacity in Africa is often very poor, in particular for Water Quality Monitoring (WQM). Citizen Science (CS) based WQM is nowadays proposed as an innovative approach to strengthen the WQM capacity (Fehri et al., 2020; Njue et al., 2019; Jollymore et al., 2017). The concept of CS is based on the potential social benefits of engaging, collaborating and actively involving citizens in data collection and knowledge generation. Yet, the quality of CS-based WQM is different as compared to reference WQM. CS-based WQM programmes need therefore to be thoroughly validated. The main objective of this study is to assess the quality of a CSbased WQM program for the Medjerda river in Tunisia

Assessing the Performance of a Citizen Science Based Water Quality Monitoring Program for Nitrates Using Test Strips Implemented in the Medjerda Hydrosystem in Northern Tunisia

Recent technological progress in water management of hydrosystems has been made to deploy efficient and effective water quality monitoring systems (WQMS). Among these, a citizen science (CS)-based water quality monitoring (WQM) program using test strips is considered as a smart tool that may aid in the production of reliable, continuous, and comprehensive data on the water quality resources of hydrosystems over a broad range of spatial and temporal scales. In this case study, the objective is to evaluate the performance of a CS-based WQM for nitrates assessment using test water quality strips for the Medjerda watershed in Northern Tunisia. Overall, 137 samples were collected from 24 sampling sites and were analyzed by 33 participants. Citizens involved in the program were regrouped in five citizen types according to their socio-economic characteristics. Statistical tests, analysis of variance (ANOVA) and multiple correspondence analyses (MCA) were achieved to survey the goodness of fit of CS as a contribution to data collection in terms of the socio-economic profile of the participant. The results show that this tool could be reliable for obtaining the levels of nitrate in water samples. Water quality test trips can conveniently be used by citizens for WQM of nitrates when they are rigorously following the manufacturer’s instructions. Additional efforts in communication and training could help to improve the performance of this CS-WQM program for nitrate in the Medjerda watershed

Involvement of Citizens in the Measurements of Water Salinity Using Test Kits in the Medjerda Watershed (Northern Tunisia)

Citizen science-based (CS) water quality monitoring (WQM) is considered as an innovative approach to enhance the hydrosystems’ monitoring. The main objective of this study is to assess the salinity monitoring adopting CS-based WQM for Medjerda watershed, the main hydrosystem of Tunisia, using test kits. The study focused on total dissolved solids (TDS) and electrical conductivity (EC) of water. 96 samples were collected to assess water salinity, from 12 sampling sites located in the Medjerda river or its main tributaries. Water salinity monitoring tests, for wet (January–March 2020) and dry (June–July 2020) periods, were performed by test kits. Regression analysis, determination coefficient (R2), F test, and Cronbach’s alpha (αC) test were performed to statistically assess the difference between the citizens’ dataset and the standard values. Results show that TDS and EC-sensitive test kits were reliable for measuring a wide range of concentrations of 207–6073 ppm and 415–9999 µS/cm, respectively. There was also a good agreement between the citizen-based outcomes and the analytical methods. Nevertheless, the reliability depends on the citizen and the parameter to be tested. Finally, the rapid and simple measurements using the test kits appear suitable to be used as CS-WQM for Medjerda hydrosystem if instructions are strictly followed, and test kits are correctly used. With more consistent training, the test kits should allow for reliable, sensitive, and precise monitoring of water quality

Environmental applications of tomato processing by-products

Sustainable management of large amounts of tomato wastes generated during industrial processing is nowadays considered as an urgent challenge. In this chapter, recent investigations on the environmental application of tomato wastes and their derived carbonaceous materials for wastewater treatment are reviewed and summarized. The effect of tomato waste properties as well as the operating conditions (including the temperature, residence time, heating gradient, and activation process) on the derived chars/activated carbons physicochemical properties are analyzed. The efficiency of nonactivated and activated chars along with the involved mechanisms during inorganic and organic pollutants removal from aqueous solutions is also reviewed.This work points out that the characteristics of tomato-derived adsorbents depend mainly on the raw precursor nature and properties, and especially on the used modification method. The highest adsorption capacities for both organics and inorganics pollutants have been obtained for activated carbons produced from the impregnation of tomato wastes with specific chemicals such as ZnCl2, FeCl2, and H3PO4. The preparation of these activated carbons should, however, occur for impregnating mass ratios (chemical/biomass) higher than 2:1, thermal treatment at temperatures lower than 650 to 700°C, and a residence time of at least 60 min. On the other hand, the optimization of the activation procedure, the use of real effluents for dynamic adsorption and the reuse of loaded tomato-derived-adsorbents in a context of circular economy and sustainable development manner are the main research and development challenges

Participatory monitoring of river flows.

Water users in northwestern Tunisia, like the Medjerda watershed, are increasingly withdrawing water from hydro-systems. This is a response to the effects of climate change that are causing strong variability. These water withdrawals result in an increase in the state of stress over time (Fehri et al., 2020). The involvement of citizens, in a participatory manner, is likely to help raise awareness among water users. The use of Mobile application has been validated in the region of Medjez El Bab by the involvement of different citizen groups (Fehri et al., 2020a; Fehri, 2021). The objective of this sheet is to capitalize on these achievements and to be used in the north-west of Tunisia for monitoring droughts or floods