1,721,036 research outputs found
Natural Organic Matter: Characterization and Removal by AOPs to Assist Drinking Water Facilities
No full textThe water sources of drinking water generally contain natural organic matter (NOM) as a result of the interactions between the hydrologic cycle and the environment. The amount, character, and properties of NOM vary considerably according to the origins of the waters and depend on the biogeochemical cycles of their surrounding environments. NOM can negatively influence water quality in drinking water supply systems, and it can significantly influence the performance of drinking water treatment processes. Hence, NOM removal is an important issue in order to optimize drinking water treatment operation and to reduce the risks of water alteration in the distribution systems. Several treatment processes can be applied for NOM removal depending on water quality, the nature of NOM, and the treatments already existing in the supply system. Among the most effective conventional solutions coagulation/flocculation, filtration, and carbon adsorption are available. An interest has recently increased toward nonconventional solutions based on membrane filtration and advanced oxidation processes (AOPs). An overview on the AOPs will be presented and discussed. Moreover, the AOP with ozone and UV radiation, with two low pressure UV lamps, at 254 and 185 nm wavelength, was experimented on a surface water in order to study the removal of odorous and pesticide, organic compounds (UV absorbance and THMs precursors) and bromate formation
Design of household sanitation facilities through a participatory approach in Iringa Municipality, Tanzania
No full textWater safety of improved source: the case study of Vilanculos (Mozambique)
No full textAccess to safe water is a major global challenge. WHO aims at ensuring it supporting actions for the improvement of water sources, but not always water from improved sources is really safe. Moreover water facilities are often located far from households, requiring collection and transport from the source to the point of use. All these steps are potentially source of recontamination. The study investigated water quality in Vilanculos, Mozambique, along the entire water supply chain to verify if drinking water from improved sources is safe. Then and identification of which are the causes of its deterioration took place
Comparison between experimental results of different technologies for arsenic removal from water intended for human consumption
No full textArsenic contamination in drinking water is a major issue in the present world. Techniques such as oxidation, precipitation and adsorption have been widely used for arsenic removal. The goal of this work is to analyze four case studies where the problem of arsenic contamination in groundwater is faced with an approach that includes experimental activities at laboratory scale and/or pilot scale. The first case study investigates the mechanisms for enhancing arsenic removal with naturally occurring Fe by the addition of an oxidizing agent (KMnO4) or a concentrated basic solution of MnO4 and AlO2. In the second case study, different experimental tests are carried out at laboratory scale in order to identify the best combination of treatments to be applied at full scale. The third case study shows the results of experimental studies followed by a full-scale upgrading for a drinking water treatment plant (DWTP) with no specific arsenic treatment in the first configuration. Last, the fourth case study investigates the performance of granular ferric oxide (GFO) with arsenic concentrations close to the Italian regulatory limit. A pilot GFO filter was installed in a DWTP. The monitoring results led to the implementation of the GFO filter at full scale
Case studies on the best practices in Italy
No full textArsenic in drinking water derived from groundwater is arguably the biggest environmental chemical human health risk known at the present time, with well over 100,000,000 people around the world being exposed. Monitoring the hazard, assessing exposure and health risks and implementing effective remediation are therefore key tasks for organisations and individuals with responsibilities related to the supply of safe, clean drinking water.
Best Practice Guide on the Control of Arsenic in Drinking Water, covering aspects of hazard distribution, exposure, health impacts, biomonitoring and remediation, including social and economic issues, is therefore a very timely contribution to disseminating useful knowledge in this area. The volume contains 10 short reviews of key aspects of this issue, supplemented by a further 14 case studies, each of which focusses on a particular area or technological or other practice, and written by leading experts in the field. Detailed selective reference lists provide pointers to more detailed guidance on relevant practice
Electrochemical Treatment of Arsenic in Drinking Water: Effect of Initial As3+ Concentration, pH, and Conductivity on the Kinetics of Oxidation
Get PDFMany technologies for the treatment of arsenic-containing drinking water are available, but most of them are more effective on arsenic oxidized forms. Therefore, the pre-oxidation of As3+ is necessary. The electrochemical processes represent a very promising method due to the simultaneous oxidation of compounds using electrochemical conditions and the reactive radicals produced. In this work, As3+ oxidation was experimentally studied at a pilot scale using an electrochemical oxidation cell (voltage: 10 V; current: 1.7 A). The effect of the initial arsenite concentration, pH, and conductivity of drinking water on the oxidation of As3+ into As5+ was investigated. The results showed that the initial As3+ concentration strongly directly influences the oxidation process. Increasing the initial arsenite concentration from 500 to 5000 μg L−1, the pseudo-first order kinetic constant (k) strongly decreased from 0.521 to 0.038 min−1, and after 10 min, only 21.3% of As3+ was oxidized (vs. 99.9% in the case of As3+ equal to 500 μg L−1). Slightly alkaline conditions (pH = 8) favored the electrochemical oxidation into As5+, while the process was partially inhibited in the presence of a more alkaline or acidic pH. The increase in conductivity up to 2000 μS cm−1 enhanced the kinetic of the oxidation, despite remaining on the same order of magnitude as in the case of conductivity equal to 700 μS cm−1. After 10 min, 99.9 and 95% of As3+ was oxidized, respectively. It is the opinion of the authors that the influence of other operational factors, such as voltage and current density, and the impact of the high concentration of other pollutants should be deeply studied in order to optimize the process, especially in the case of an application at full scale. However, these results provide helpful indications to future research having highlighted the influence of initial As3+ concentration, pH, and conductivity on the electrochemical oxidation of arsenic
Sicurezza dell’acqua per uso umano
No full textIl numero si chiude con la Sezione In breve, che ospita una presentazione curata da Drusiani della prossima edizione del Festival dell’Acqua, che si terrà in ottobre a Bari; la Sezione prosegue con un contributo di Abbà, Biasibetti, Collivignarelli e Sorlini sul tema della sicurezza dell’acqua per uso umano, che descrive l’approccio al problema introdotto nel 2004 dall’Organizzazione Mondiale di Sanità; quest’ultimo prevede l’istituzione del Water Safety Plan o Piano di Sicurezza dell’Acqua (PSA), che si basa sulla valutazione e gestione del rischio di contaminazione dell’acqua in tutte le fasi della filiera idrica, dalla captazione al punto di consumo
INNOVATION IN CONSTRUCTION AND DEMOLITION WASTE SELECTION FOR THE PRODUCTION OF HIGH-QUALITY RECYCLED AGGREGATES
No full textItalian production of construction and demolition waste (CDW) reached about 62 million tons in 2022. Despite the high recovery rate (79.8 percent), most of the treated CDW is stored waiting to be used. In most cases, the recycled aggregates (RAs) resulting from CDW processing turn out to be of low quality and mostly destined for "low-grade" applications (road and railway pavements, civil engineering works, back-fills or environmental recoveries). The use of RAs in so-called "high-grade" applications, such as concrete production, is unfortunately limited today by several factors, including the type and origin of RAs, their mechanical properties (often lower than those of natural aggregates) and the potential release of contaminants. In fact, concrete production requires an RA that has similar performance to natural aggregate. This is the main objective of the Life CDW Circle project, co-funded by the European Union and presented in this paper, which aims to achieve total recycling and use of treated CDW, thanks to an innovative sorting technology that allows the separation of different aggregate fractions (aggregates, bricks, tiles, etc.) and the production of RAs with high added value. During the experimental activities, the resulting RAs will be characterized and used for concrete production. After the experimental phase, the project partners will develop appropriate business models, creating an ecosystem with sector stakeholders. The aim of the paper is to provide an overview of CDW and RAs production and use in Italy. In addition, the new Life CDW Circle project structure and objectives will be presented
Technologies for the control of emerging contaminants in drinking water treatment plants
Get PDFIn recent years, so-called emerging contaminants (ECs) have attracted growing interest as they have been detected in reservoirs and even in drinking water. The new proposal Drinking Water Directive (2018) provides for the introduction of new parameters relevant to the ECs category. As these contaminants today tend to be present in a growing number of water sources, provide treatment systems that ensure compliance with regulatory limits and the protection of public health has become essential. The aim of this paper is to provide essential information on five ECs (more precisely: haloacetic acids, microcystine-LR, Perfluoro Alkylated Substances, Bisphenol-A and Nonylphenol) and to explain useful processes for their removal in a DWTPs. For each contaminant, current and future legislation, health aspects and in particular a focus of the chemical and physical removal technologies already existing and under study are reported. The effectiveness of both conventional (e.g. chemical oxidation, coagulation/flocculation, adsorption on Granular Active Carbon (GAC), ion exchange) and advanced treatments (e.g. membrane filtration, AOPs) is presented and discussed
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