Concept for an integrated evaluation of arsenic removal technologies: demonstrated in a case study

2002 ◽  
Vol 2 (2) ◽  
pp. 267-274 ◽  
Author(s):  
A. Ruhland ◽  
M. Jekel
Keyword(s):  
Arsenic Removal ◽  
Evaluation Criteria ◽  
Treatment Plant ◽  
Ferric Hydroxide ◽  
Lower Saxony ◽  
Direct Filtration ◽  
Economical Evaluation ◽  
Removal Processes ◽  
Removal Technologies

A concept for a technical, ecological and economical evaluation of arsenic removal technologies is introduced and demonstrated on the basis of three alternative arsenic removal processes, direct filtration with FeCl3, adsorptive filtration with FeSO4 and adsorption on granulated ferric hydroxide, which were tested in a case study. A set of evaluation criteria is worked out and discussed with regard to the case study. Further, a multi criteria decision support instrument is described and used for identifying the preferential arsenic removal process. The ranking of the analysed alternatives is presented. The results base on the data of a full scale treatment plant of a water supplier in the Lower Saxony, Germany. The adsorption on granulated ferric hydroxide is ranked as preferential process - alternative for arsenic removal on the conditions of the case study.

Comparison between experimental results of different technologies for arsenic removal from water intended for human consumption

2019 ◽  
Vol 14 (4) ◽  
pp. 884-896
Author(s):  
Maria Cristina Collivignarelli ◽  
Silvestro Damiani ◽  
Sabrina Sorlini
Keyword(s):  
Drinking Water ◽  
Arsenic Removal ◽  
Experimental Studies ◽  
Treatment Plant ◽  
Arsenic Contamination ◽  
Full Scale ◽  
Laboratory Scale ◽  
Basic Solution ◽  
First Case

Abstract Arsenic 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.

scholarly journals An overview of main arsenic removal technologies

2018 ◽  
Vol 11 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Ronald Zakhar ◽  
Ján Derco ◽  
František Čacho
Keyword(s):  
Drinking Water ◽  
Membrane Filtration ◽  
Arsenic Removal ◽  
Chemical Precipitation ◽  
Contaminated Water ◽  
The World ◽  
Removal Processes ◽  
Removal Technologies ◽  
High Concentrations ◽  
Exchange Membrane

Abstract Arsenic (As) is metalloid, naturally present in the environment but also introduced by human activities. It is toxic and carcinogenic and its exposure to low or high concentrations can be fatal to human health. Arsenic contamination in drinking water threatens more than 150 million peoples all over the world. Therefore, treatment of As contaminated water is of unquestionable importance. The present review begins with an overview of As chemistry, distribution and toxicity, which are relevant aspects to understand and develop remediation techniques. The most common As removal processes (chemical precipitation, adsorption, ion exchange, membrane filtration, phytoremediation and electrocoagulation) are presented with discussion of their advantages, drawbacks and the main recent achievements.

Side effects of cultured bacteria addition in wastewater collection system on plant operations – a case study

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
Yanjin Liu ◽  
Giraldo Eugenio
Keyword(s):  
Energy Use ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Collection System ◽  
Oil And Grease ◽  
Odor Control ◽  
Plant Operations ◽  
Cultured Bacteria ◽  
Wastewater Collection

Cultured bacteria addition is one of the technologies used for odor control and FOG (fat, oil, and grease) removal in wastewater collection systems. This study investigated the efficiency of bacterial addition on wastewater odor control by conducting a set of full scale trials in a 60,000 cubic meter per day system for a period of two years. The objectives of this study were: (i) to identify factors that could impact wastewater treatment plant (WWTP) operations due to the effect of bacterial addition in the collection system, (ii) to estimate/understand the level of those impacts, and (iii) to present some interesting findings from the completed case study. The plant operation data before and during the bacterial addition were reviewed. The application of the cultured bacteria presented in the study was found to have significant impacts on the operation of the WWTP in terms of influent biological oxygen demand (BOD) and total suspended solids (TSS) loading, primary settling, sludge production, energy use, dissolved sulfides concentration, and methane production.

Arsenic removal by MF membrane with chemical sludge adsorption and NF membrane equipped with vibratory shear enhanced process

2003 ◽  
Vol 3 (5-6) ◽  
pp. 303-310 ◽  
Author(s):  
S.-H. Yi ◽  
S. Ahmed ◽  
Y. Watanabe ◽  
K. Watari
Keyword(s):  
Arsenic Removal ◽  
Membrane Surface ◽  
Membrane Process ◽  
Low Concentrations ◽  
Strong Shear ◽  
Low Levels ◽  
Removal Processes ◽  
Removal Of Arsenic ◽  
Concentration Polarization Layer ◽  
Chemical Sludge

Conventional arsenic removal processes have difficulty removing low concentrations of arsenic ion from water. Therefore, it is very hard to comply with stringent low levels of arsenic, such as below 10 μg/L. So, we have developed two arsenic removal processes which are able to comply with more stringent arsenic regulations. They are the MF membrane process combined with chemical sludge adsorption and NF membrane process equipped with the vibratory shear enhanced process (VSEP). In this paper, we examine the performance of these new processes for the removal of arsenic ion of a low concentration from water. We found that chemical sludge produced in the conventional rapid sand filtration plants can effectively remove As (V) ions of H2AsO4- and HAsO42- through anion exchange reaction. The removal efficiency of MF membrane process combined with chemical sludge adsorption increased to about 36%, compared to MF membrane alone. The strong shear force on the NF membrane surface produced by vibration on the VSEP causes the concentration polarization layer to thin through increased back transport velocity of particles. So, it can remove even dissolved constituents effectively. Therefore, As (V) ions such as H2AsO4- and HAsO42- can be removed. The concentration of As (V) ions decreased from 50 μg/L to below 10 μg/L and condensation factor in recirculating water increased up to 7 times by using NF membrane equipped with VSEP.

Cost-effective water treatment of polluted surface water by using direct filtration and granular activated carbon filtration

2002 ◽  
Vol 2 (1) ◽  
pp. 233-240 ◽  
Author(s):  
J. Cromphout ◽  
W. Rougge
Keyword(s):  
Activated Carbon ◽  
Water Treatment ◽  
Treatment Process ◽  
Treatment Plant ◽  
Granular Activated Carbon ◽  
Cost Effective ◽  
Water Treatment Plant ◽  
Direct Filtration ◽  
Carbon Filtration ◽  
Effective Water

In Harelbeke a Water Treatment Plant with a capacity of 15,000 m3/day, using Schelde river water has been in operation since April 1995. The treatment process comprises nitrification, dephosphatation by direct filtration, storage into a reservoir, direct filtration, granular activated carbon filtration and disinfection. The design of the three-layer direct filters was based on pilot experiments. The performance of the plant during the five years of operation is discussed. It was found that the removal of atrazin by activated carbon depends on the water temperature.

The Implementation of Biological Phosphorus and Nitrogen Removal with the Bio-Denipho Process on a 265,000 PE Treatment Plant

1992 ◽  
Vol 25 (4-5) ◽  
pp. 161-168 ◽  
Author(s):  
J. Einfeldt
Keyword(s):  
Nitrogen Removal ◽  
Treatment Plant ◽  
First Year ◽  
In Series ◽  
Design Loads ◽  
Last Stage ◽  
Two Stages ◽  
The City ◽  
Biological Phosphorus

A process, called Bio-Denipho, for combined biological phosphorus and nitrogen removal in a combination of an anaerobic tank and two oxidation ditches is described. In this process the anaerobic tank consisting of three sections working in series is followed by two oxidation ditches. These too are working in series, but with both inlet to and outlet from the tanks changing in a cycle. The Bio-Denipho process is described specifically for the process itself and as a case study for the implementation of the process on a 265,000 pe wastewater treatment plant for the city of Aalborg in Denmark. The plant was designed and erected in two stages and the last stage was inaugurated October 31,1989. Lay-out and functions for the plant is described and design loads, plan lay-out and tank volumes are given in this paper together with performance data for the first year in operation.

Nitrogen removal from wastewater treatment lagoons

1999 ◽  
Vol 39 (6) ◽  
pp. 191-198 ◽  
Author(s):  
Timothy J. Hurse ◽  
Michael A. Connor
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Ammonia Removal ◽  
Contour Plot ◽  
Removal Mechanism ◽  
Dissolved Oxygen Concentration ◽  
Physical Processes ◽  
Contour Plots ◽  
Removal Processes

In an attempt to gain a better understanding of ammonia and nitrogen removal processes in multi-pond wastewater treatment lagoons, an analysis was carried out of data obtained during regular monitoring of Lagoon 115E at the Western Treatment Plant in Melbourne. To do this, a contour plot approach was developed that enables the data to be displayed as a function of pond number and date. Superimposition of contour plots for different parameters enabled the dependence of ammonia and nitrogen removal rates on various lagoon characteristics to be readily assessed. The importance of nitrification as an ammonia removal mechanism was confirmed. Temperature, dissolved oxygen concentration and algal concentration all had a significant influence on whether or not sizeable nitrifier populations developed and persisted in lagoon waters. The analysis made it evident that a better understanding of microbial, chemical and physical processes in lagoons is needed before their nitrogen removal capabilities can be predicted with confidence.

scholarly journals Appraising psychotherapy case studies in practice-based evidence: introducing Case Study Evaluation-tool (CaSE)

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Greta Kaluzeviciute
Keyword(s):  
Case Studies ◽  
Evaluation Criteria ◽  
Internal Validity ◽  
Knowledge Generation ◽  
Evaluation Tool ◽  
Third Way ◽  
Study Evaluation ◽  
Essential Components ◽  
Randomised Controlled

AbstractSystematic case studies are often placed at the low end of evidence-based practice (EBP) due to lack of critical appraisal. This paper seeks to attend to this research gap by introducing a novel Case Study Evaluation-tool (CaSE). First, issues around knowledge generation and validity are assessed in both EBP and practice-based evidence (PBE) paradigms. Although systematic case studies are more aligned with PBE paradigm, the paper argues for a complimentary, third way approach between the two paradigms and their ‘exemplary’ methodologies: case studies and randomised controlled trials (RCTs). Second, the paper argues that all forms of research can produce ‘valid evidence’ but the validity itself needs to be assessed against each specific research method and purpose. Existing appraisal tools for qualitative research (JBI, CASP, ETQS) are shown to have limited relevance for the appraisal of systematic case studies through a comparative tool assessment. Third, the paper develops purpose-oriented evaluation criteria for systematic case studies through CaSE Checklist for Essential Components in Systematic Case Studies and CaSE Purpose-based Evaluative Framework for Systematic Case Studies. The checklist approach aids reviewers in assessing the presence or absence of essential case study components (internal validity). The framework approach aims to assess the effectiveness of each case against its set out research objectives and aims (external validity), based on different systematic case study purposes in psychotherapy. Finally, the paper demonstrates the application of the tool with a case example and notes further research trajectories for the development of CaSE tool.

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