Functional and financial analysis of an inclined step solar desalination using phase change nanomaterials.

Recent decades have seen a shortage of water, which has led scientists to concentrate on solar desalination technologies. The present study examines the solar water desalination system with inclined steps, while considering various phase change materials (PCMs). The findings suggest that the incorporation of PCM generally enhances the productivity of the solar desalination system. Additionally, the combination of nanoparticles has been used to PCM, which is a popular technique utilized nowadays to improve the efficiency of these systems. The current investigation involves the transient modeling of a solar water desalination system, utilizing energy conservation equations. The equations were solved using the Runge-Kutta technique of the ODE23s order. The temperatures of the salt water, the absorbent plate of the glass cover, and the PCM were calculated at each time. Without a phase changer, the rate at which fresh water is produced is around 5.15 kg/m2·h. The corresponding mass flow rates of paraffin, n-PCM I, n-PCM III, n-PCM II, and stearic acid are 22.9, 28.9, 5.9, 11.9, and 73 kg/m2·h. PCMs, with the exception of stearic acid, exhibit similar energy efficiency up to an ambient temperature of around 29°. However, at temperatures over 29°, n-PCM II outperforms other PCM.

Moringa oleifera Plant as potent alternate to Chemical Coagulant in Water Purification

Abstract Quality of groundwater is threatened due to pollution by industrial, domestic and agricultural waste. A large number of populations are residing in rural areas which are unable to afford high cost water purifiers due to their low income as well as limited awareness. However, limited availability of fresh water has become a critical issue in developing countries. Around 1.2 billion population is deprived of affordable and safe water for their domestic need. Additionally, chemical coagulants which are nowadays being used for water purification pose severe and numerous health hazards to human. Thus utilization of easily accessible natural coagulant for water purification might offer a sustainable, practical and cost effective solution to the current alarming situation in developing countries. Several experimental findings have shown strong efficiency of Moringa oleifera plant extracts obtained from different solvents in the improvement of water quality parameters including physicochemical (such as pH, hardness, turbidity, metallic impurities, total dissolved solid) and biological (E.coli count) parameter. We have also highlighted the limitations and advantages of chemical coagulation in water purification. Altogether, this review summarizes one such miracle tree which has shown significant potential as a natural coagulant and its associated underlying mechanism in water purification process.

Application of HACCP for development of quality risk management in a water purification system

Abstract The present work reports the implementation of the Hazard Analysis Critical Control Point (HACCP) methodology to analyze the water purification system of a pharmaceutical site, in order to assure the system quality and prevent failures. As a matter of fact, the use of HACCP for development and implementation of Quality Risk Management (QRM) is not usual in pharmaceutical plants and it is applied here to improve the performance of the water purification system of a polymerization pilot plant used to manufacture pharmaceutical grade polymer microparticles. Critical Control Points (CCP) were determined with the aid of a decision tree and questions were made to characterize whether identified hazards constitute actual CCPs and should be monitored. When deviations were detected, corrective actions were performed and action plans were used for following-up and implementation of corrective actions. Finally, microbiological and physicochemical parameters were analyzed and the obtained results were regarded as appropriate. Therefore, it is shown that HACCP constitutes an effective tool for identification of hazards, establishment of corrective actions and monitoring of the critical control points that impact the process and the quality of the final pharmaceutical product most significantly.

Development of triaminotriazine functionalized graphene oxide capped chitosan porous composite beads for nutrients remediation towards water purification.

The porous, definite and nitrogen rich triaminotriazine (TAT) grafted graphene oxide (GO) known as TATGO composite was developed for nutrients (NO3- and PO43-) retention. Additionally, the structural property of TATGO composite was improved with the use of chitosan (CS) to produce easily separable TATGO@CS hybrid beads which possess the significant NO3- and PO43- adsorption capacities of 58.46 and 61.38 mg/g respectively than their individual materials. The instrumentations such as SEM, TGA, FTIR, EDAX, XRD and BET studies were executed for adsorbents. The optimization of the parameters accountable for adsorption process was performed in batch scale. The effect of isotherms (Langmuir, Freundlich and Dubinin-Radushkevich (D-R)), kinetics (pseudo-first/second order and particle/intraparticle diffusion) and thermodynamic parameters (ΔG°, ΔH° and ΔS°) of the adsorption was explored. The removal mechanism of TATGO@CS hybrid beads was to be electrostatic attraction on NO3- and PO43-. The field applicability and reuse of TATGO@CS hybrid beads was also inspected.

Sustainability assessment of long-term, widely used household Kanchan Arsenic Filters in Nepal.

This study revealed the status of 2833 Kanchan Arsenic Filters (KAFs), aged 2 months to over 10 years, distributed in Nepal. Thirty percent of the filters were being used, but usage status generally declined 4 years after installation. Lack of use was mostly due to breakage or leaks (74%), which users did not know how to repair. Some 1283 filters (65%) were abandoned, and users returned to drinking arsenic-contaminated water. Water quality tests showed that the average KAF arsenic removal rate was 75%, and 87 and 62% of the samples met Nepal's drinking water quality standards and World Health Organization guidelines, respectively. The KAF arsenic removal amount was significantly influenced by the arsenic and iron concentrations of influent water and KAF type. The concrete square type showed the best performance in usage status and arsenic removal capacity, namely 57 and 83%, respectively. Long-term use of KAFs (more than 4 years) was assumed to be a cause of the decreasing capacity of iron nails to supply ferric hydroxide to influent water, which led to decreased arsenic removal capacity. Thus, replacement of older iron nails may restore the arsenic removal capacity of KAFs.

Barriers and Enabling Factors Associated with the Implementation of Household Solar Water Disinfection: A Qualitative Study in Northwest Ethiopia.

Household water treatment including solar disinfection (SODIS) is recognized worldwide as an important intervention for prevention and control of diarrheal and other waterborne diseases. However, in Ethiopia's countryside, SODIS is not being practiced. Therefore, the objective of this qualitative study conducted in villages of Dabat district in northwest Ethiopia was to explore barriers to and enabling factors for consistent and wider implementation of SODIS. This phenomenological study design included four focus group discussions with 25 parents of children younger than 5 years and interviews with four key informants to elicit their experiences and opinions. ATLAS.ti 8.0 software (GmbH, Berlin, Germany) was used for data organization, and the content was analyzed thematically. Enabling factors were categorized into four themes, such as supportive values for SODIS (positive attitude, advantage of SODIS, and cultural acceptance of SODIS), consistent use of SODIS (community's interest, health education, availability of bright sunlight, and simplicity of the method), participation of family and community in daily implementation of the SODIS process (controlling theft of bottles and recognizing the importance of SODIS technology), and willingness to pay for new polyethylene terephthalate (PET) bottles. On the other hand, barriers were grouped into three themes such as sociocultural (poor knowledge, hesitation to leave SODIS bottles unguarded outdoor, less attention, and unplanned social events), environmental (cloud, shadow over SODIS bottles, turbidity and leeches in source water, and geographical settings), and behavioral (mishandling of SODIS bottles and drinking water). The analysis of the data revealed that all the participants had positive attitude toward the implementation of SODIS, and it was culturally accepted. They identified the barriers to and enabling factors for the implementation of SODIS. Promoting enabling factors and mitigating barriers are substantially important for consistent implementation of SODIS as a long-term interventional measure widely in rural Ethiopia for the achievement of the goal of safe drinking water for all.

Structuring an integrated water-energy-food nexus assessment of a local wind energy desalination system for irrigation.

Desalination is increasingly put forward as a sustainable local solution to water scarcity in combination with the exploitation of renewable energy sources. However, the complexity of the resource nexus entails the unavoidable existence of pros and cons across its various dimensions that can only be assessed at different scales of analysis. In turn, these pros and cons entail different winners and losers among the different social actors linked through the nexus. To address these challenges, a novel approach to resource nexus assessment is put forward, based on multi-scale integrated analysis of societal and ecosystem metabolism (MuSIASEM) and recognizing the resource nexus as a wicked problem. The integrated representation identifies the existence of biophysical constraints determined by processes both under human control (in the technosphere) and beyond human control (in the biosphere). The approach is illustrated with a local case study of desalination in the Canary Islands, Spain. The material presented has been generated in the context of the project "Moving towards adaptive governance in complexity: Informing nexus security" (MAGIC) for use in participatory processes of co-production of knowledge claims about desalination, a prerequisite for informed policy deliberation.

Efficiency of a low-cost pyramid-shaped solar still for pesticide removal from highly contaminated water.

Water pollution by pesticides and other chemical contaminants is a subject of major importance due to the risk for human health and the environment. The search for remediation processes able to withdraw chemical contaminants from water and to allows water reuse is an urgent need. Herein, a simple and cheap system for pesticides removal was constructed and evaluated using water samples contaminated with two widely used herbicides (imazapic and imazethapyr, at g L-1 level). Operation parameters and process efficiency, in terms of removal rate in the reclaimed water and degradation rate of pesticides in the dry residue, were quantitatively determined. The model was tested in real-world field experiments and was able to remove more than 99.95% of both contaminants from a 10 L solution containing 4.16 ±â€¯0.94 g of imazethapyr and 1.31 ±â€¯0.17 g of imazapic, generating reusable water with minimum volume loss (<2.5%). Liquid chromatography coupled to mass spectrometry was used to determine the herbicides content in all samples and to estimate the degree of degradation of the substances as well as the occurrence of transformation products of imazapic and imazethapyr. The system efficiency in removing contaminants of emerging concern from surface water was also evaluated. The process have generated output water with undetected levels for two fungicides present in a local river in Southern Brazil.

Online assessment of sand filter performance for bacterial removal in a full-scale drinking water treatment plant.

Microbiological risks associated with drinking water can be minimized by providing enhanced integrity monitoring of bacterial removal by water treatment processes. This study aimed to evaluate the efficacy of real-time bacteriological counters for continuously assessing the performance of a full-scale sand filter to remove bacteria. Over the course of an 8-day evaluation, online counting of bacteria was successfully performed, providing continuous bacterial counts in the sand filter influent and effluent over approximate ranges from 17 × 104 to 94 × 104 and from 0.2 × 104 to 1.3 × 104 counts/mL, respectively. Periodic variations were observed with online bacterial counts in the sand filter influent because of the changes in the performance of flocculation and sedimentation processes. Overall, online removal rates of bacteria determined during the full-scale test were 95.2-99.3% (i.e., 1.3-2.2-log), indicating that online bacterial counting can continuously demonstrate over 1.3-log removal in the sand filter. Real-time bacteriological counting technology can be a useful tool for assessing variability and detecting bacterial breakthrough. It can be integrated with other online water quality measurements to evaluate underlying trends and the performance of sand filters for bacterial removal, which can enhance the safety of drinking water.

Characterization the level of a new low-cost adsorbent material prepared from date palm kernel pits via DP-LIBS and ICP-OES spectroscopic techniques.

We successfully developed a fast detection system based on orthogonal dual-pulsed laser-induced breakdown spectroscopy (DP-LIBS) to characterize the level of a new low-cost adsorbent material prepared from date palm kernel pits. The activated carbon (AC) was produced from different heated and chemically treated date palm kernel pit samples to be used as adsorbent material for the removal of some pollutants from wastewater. The quantitative, as well as qualitative analysis, was performed using the DP-LIBS analytical technique. Hence, the valuable elements like the carbon present in the date palm kernel pits was perfectly recognized. The registered spectra of the sample cover the spectral lines of carbon. The quantitative analysis of carbon, carried out in different samples of date palm kernel pits, using DP-LIBS revealed that the estimated limit of detection of carbon in these samples is about 225.19 mg/L. The precision of DP-LIBS data for determining the concentration of activated carbon element present in the date palm kernel pits was validated via the inductively coupled plasma-optical emission spectrometry (ICP-OES) as a standard technique.

Application and performance evaluation of a cost-effective vis- LED based fluidized bed reactor for the treatment of emerging contaminants.

Visible light induced photocatalysis is considered as one of the most potential technologies which can achieve new levels of sustainability in water treatment. The current study explores the performance of immobilized visible light active catalyst on inert media for light driven catalysis of pharmaceuticals. These coated media is used in a continuous flow fluidized column reactor equipped with spirally arranged visible Light Emitting Diodes (LEDs) as irradiation source. The treatment efficiency of the system is evaluated for the removal of pharmaceutical drugs such as carbamazepine, diclofenac and ibuprofen. For the present study, system parameters such as light intensity and flow rate are optimized for maximum removal rate. The system shows complete elimination of the pharmaceuticals under the given experimental conditions. Complete mineralization of the target compounds are confirmed by TOC analysis. Recyclability is an important attribute for full scale commercialization of a treatment technology. An investigation on the reusability study of the photocatalyst displayed no significant reduction in the removal efficiency for a run of six cycles, hence rendering the photocatalyst reusable. The results acquired indicate an immense potential for scaling up the photoreactor as a sustainable tertiary treatment technology in water treatment plants.

Adsorptive removal of bisphenol A from aqueous solutions using phosphonated levan.

In this study, the potential use of phosphonated Halomonas Levan (PhHL) as a natural and cost effective adsorbent for Bisphenol A (BPA), was systematically investigated via the study of the adsorption equilibrium, kinetics, and reuse potential as well as the interpretation of adsorption mechanism. The effects of pH and temperature on the adsorption were also evaluated. The maximum amount of BPA adsorbed on the unit weight of PhHL was determined as 104.8 (∓5.02) mg/g (at 298 K) and the maximum adsorption capacity was calculated as 126.6 mg/g by Sips model. FTIR and XPS studies were conducted to elucidate the adsorption mechanism. Based on the obtained results OH-pi and CH-pi interactions were found to be effective in the adsorption mechanism. The reuse ability was studied with three cycles of adsorption-desorption, and the results showed that the BPA adsorbed per gram of the PhHL decreased 28.6% after the third cycle. This study has shown that PhHL can be used as an effective adsorbent for the removal of BPA from aqueous solutions. The obtained results may be useful in the development of PhHL based adsorption systems for the removal of EDCs with similar chemical properties to BPA.

Life cycle assessment of a large water treatment plant in Turkey.

The objective of this study is to assess the environmental sustainability of a large water treatment plant through life cycle assessment (LCA) approach. This study is a pioneering one that explores the environmental impacts of a water treatment plant in Turkey by using the data collected from an actual plant. Decision makers of the treatment plant under investigation, operators of similar installations, and the scientific researchers that work on LCA of water treatment facilities are defined as the target audience. GaBi software is used for the LCA model, and CML 2001 method is adopted to calculate the results given per 1 m3 water ready to be distributed to the city. The plant serves about 2,600,000 people generating a maximum potable water flow rate of 400,000 m3/day. In the facility, 0.57 kWh of electricity is required to obtain 1 m3 of water. Of this total electricity consumption, 85% is allocated to inlet and outlet pumping stations. The results denote that the environmental impacts are dominated by electricity consumption that in turn depends on the energy source/s adopted. Sensitivity analysis on energy sources reveals the following outcomes: In case of using hard coal as energy source rather than grid mix, impacts are increased apart from freshwater aquatic ecotoxicity potential, ozone layer depletion potential, and abiotic depletion potential elements. Once solar panels are used instead of grid mix, values for all impact categories except abiotic depletion potential elements and human toxicity potential are lowered. The usage of wind turbines in place of grid mix results in 29 to 84% reductions in all investigated impact categories. The best option to decrease the environmental impacts is attained when energy is generated using wind turbines. As pumps having 90% efficiency replace the pumps with 60% efficiency, reductions ranging from 15 to 24% on all impact categories are obtained. The work performed for this study should be further pursued to obtain more representative inventory data for countries with scarce LCA studies.

Innovative sludge pretreatment technology for impurity separation using micromesh.

In order to reduce the impacts on sludge treatment facilities caused by impurities such as fibers, hairs, plastic debris, and coarse sand, an innovative primary sludge pretreatment technology, sludge impurity separator (SIS), was proposed in this study. Non-woven micromesh with pore size of 0.40 mm was used to remove the impurities from primary sludge. Results of lab-scale tests showed that impurity concentration, aeration intensity, and channel gap were the key operation parameters, of which the optimized values were below 25 g/L, 0.8 m3/(m2 min), and 2.5 cm, respectively. In the full-scale SIS with treatment capacity of 300 m3/day, over 88% of impurities could be removed from influent and the cleaning cycle of micromesh was more than 16 days. Economic analysis revealed that the average energy consumption was 1.06 kWh/m3 treated sludge and operation cost was 0.6 yuan/m3 treated sludge.

UV fluences required for compliance with ballast water discharge standards using two approved methods for algal viability assessment.

This study investigates the extra UV fluence needed to meet the International Maritime Organisation's ballast water discharge standards for the 10-50 µm size-class using the approved vital stain (VS) method compared to the Most Probable Number (MPN) method for organism viability assessment. Low- and medium pressure UV collimated beam treatments were applied to natural algae collected in temperate and tropical water environments and analysed using both methods. About 10 times higher UV fluence was required to meet discharge standards when using VS compared to MPN. Implementing a dark-hold period after UV treatments decreased algal viability. Length of dark-hold period to meet discharge standards decreased with increasing UV fluence. No significant differences between temperate and tropical samples were observed. The results showed that UV treated algae assessed using the VS method could meet discharge standards by increasing fluence and/or introducing a dark-hold period.

Cost-Effective, Wireless, Portable Device for Estimation of Hexavalent Chromium, Fluoride, and Iron in Drinking Water.

The quality of drinking water often remains unknown to people because of the inadequacy of cost-effective testing systems that can be used in the field. Major portable instruments for water-quality analysis include ion-selective electrodes (ISE) or colorimeters. These are low-cost devices, but in the case of multiple-analyte detection, such as that of hexavalent chromium (Cr), fluoride (F-), and iron (Fe), with a single instrument, no portable systems are available, to the authors' knowledge. In this paper, we demonstrate the use of a low-cost (approximate price of INR 1500 or US$20), portable colorimetric system that can be operated with Android smartphones wirelessly to estimate the contamination levels of Cr(VI), F-, and Fe in drinking water. This system also generates absorption spectra by recording the absorbance of the analyte using a light-dependent-resistor (LDR) sensor. An Android-application software named Spectruino was developed to calculate the concentrations of the analytes. We strongly believe that this cost-effective, portable system will be very useful in improving human health by ensuring drinking-water quality throughout India.

A granular activated carbon/electrochemical hybrid system for onsite treatment and reuse of blackwater.

Over 1/3 of the global population lacks access to improved sanitation, leading to disease, death, and impaired economic development. Our group is working to develop rapidly deployable, cost-effective, and sustainable solutions to this global problem that do not require significant investments in infrastructure. Previously, we demonstrated the feasibility of a toilet system that recycles blackwater for onsite reuse as flush water, in which the blackwater is electrochemically treated to remove pathogens due to fecal contamination. However, this process requires considerable energy (48-93 kJ/L) to achieve complete disinfection of the process liquid, and the disinfected liquid retains color and chemical oxygen demand (COD) in excess of local discharge standards, negatively impacting user acceptability. Granular activated carbon (GAC) efficiently reduces COD in concentrated wastewaters. We hypothesized that reduction of COD with GAC prior to electrochemical treatment would both improve disinfection energy efficiency and user acceptability of the treated liquid. Here we describe the development and testing of a hybrid system that combines these technologies and demonstrate its ability to achieve full disinfection with improved energy efficiency and liquid quality more suitable for onsite reuse and/or discharge.

Feasibility study of cadmium adsorption by palm oil fuel ash (POFA)-based low-cost hollow fibre zeolitic membrane.

Palm oil fuel ash (POFA) is an agricultural waste which was employed in this study to produce novel adsorptive ceramic hollow fibre membranes. The membranes were fabricated using phase inversion-based extrusion technique and sintered at 1150 °C. The membranes were then evaluated on their ability to adsorb cadmium (Cd(II)). These membranes were characterised using (nitrogen) N2 adsorption-desorption analysis, field emission scanning electron microscopy-energy-dispersive X-ray spectroscopy (FESEM-EDX) mapping, X-ray fluorescence (XRF), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses while adsorptivity activity was examined by batch adsorption studies. The adsorption test results show that the quantity of hollow fibre used and water pH level significantly affected the adsorption performance with the 3-fibre membrane yielding 96.4% Cd(II) removal in 30 min equilibrium time at pH 7. These results are comparable to those reported by other studies, and hence demonstrate a promising alternative of low-cost hollow fibre adsorbent membrane. Graphical abstract Figure of FESEM image of the hollow fibre, proposed mechanism and the graph of percentage removal of Cd(II) using POFA.

Effect of water-to-cement ratio and curing method on the strength, shrinkage and slump of the biosand filter concrete body.

The biosand filter is a household-level water treatment technology used globally in low-resource settings. As of December 2016, over 900,000 biosand filters had been implemented in 60 countries around the world. Local, decentralized production is one of the main advantages of this technology, but it also creates challenges, especially in regards to quality control. Using the current recommended proportions for the biosand filter concrete mix, slump was measured at water-to-cement ratios of 0.51, 0.64 and 0.76, with two replicates for each level. Twenty-eight-day strength was tested on four replicate cylinders, each at water-to-cement ratios of 0.51, 0.59, 0.67 and 0.76. Wet curing and dry curing were compared for 28-day strength and for their effect on shrinkage. Maximum strength occurred at water-to-cement ratios of 0.51-0.59, equivalent to 8-9.3 L water for a full-scale filter assuming saturated media, corresponding to a slump class of S1 (10-40 mm). Wet curing significantly improved strength of the concrete mix and reduced shrinkage. Quality control measures such as the slump test can significantly improve the quality within decentralized production of biosand filters, despite localized differences in production conditions.

Using carbonized low-cost materials for removal of chemicals of environmental concern from water.

Adsorption on low-cost biochars would increase the affordability and availability of water treatment in, for example, developing countries. The aim of this study was to identify the precursor materials and hydrochar surface properties that yield efficient removal of compounds of environmental concern (CEC). We determined the adsorption kinetics of a mixture containing ten CECs (octhilinone, triclosan, trimethoprim, sulfamethoxasole, ciprofloxacin, diclofenac, paracetamol, diphenhydramine, fluconazole, and bisphenol A) to hydrochars prepared from agricultural waste (including tomato- and olive-press wastes, rice husks, and horse manure). The surface characteristics of the hydrochars were evaluated via diffuse reflectance infrared spectroscopy (DRIFTS), X-ray photoelectron spectroscopy (XPS), and N2-adsorption. Kinetic adsorption tests revealed that removal efficiencies varied substantially among different materials. Similarly, surface analysis revealed differences among the studied hydrochars and the degree of changes that the materials undergo during carbonization. According to the DRIFTS data, compared with the least efficient adsorbent materials, the most efficient hydrochars underwent more substantial changes during carbonization.