scholarly journals Simulating the Effect of Water Recirculation on Flotation through Ion-Spiking: Effect of Ca2+ and Mg2+

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1033
Author(s):  
Mathew Dzingai ◽  
Malibongwe Manono ◽  
Kirsten Corin
Keyword(s):  
Froth Flotation ◽  
Inorganic Ions ◽  
Cost Effective ◽  
Threshold Concentration ◽  
Plant Water ◽  
Water Recovery ◽  
Recycled Water ◽  
Alternative Source ◽  
Froth Stability ◽  
Concentrate Grade

Froth flotation is a multifaceted complex process which is water intensive. The use of recycled water as an alternative source of water to meet water demands of the process may introduce deleterious inorganic ions that affect the mineral surface, pulp chemistry, and reagent action, hence the need to establish whether threshold ion concentrations exist beyond which flotation performance will be adversely affected. This is of paramount importance in informing appropriate recycle streams and allowing simple, cost-effective water treatment methods to be applied. Here we report that increasing ionic strengths of synthetic plant water (SPW); 3, 5, and 10 SPW respectively, resulted in an increase in water recovery in the order 0.073 mol·dm−3 (3 SPW) < 0.121 mol·dm−3 (5 SPW) < 0.242 mol·dm−3 (10 SPW), indicating an increase in froth stability as higher water recoveries are linked to increased froth stabilities. This behavior is linked to the action of inorganic electrolytes on bubble coalescence which is reported in literature. There was, however, no significant effect on the valuable mineral recovery. Spiking 3 SPW to 400 mg/L Ca2+ resulted in higher copper and nickel grades compared to 3 SPW, 5 SPW, and 10 SPW and was deemed to be the Ca2+ ion threshold concentration for this study since 3 SPW spiked with further Ca2+ to a concentration of 800 mg/L resulted in a decrease in the concentrate grade. The spiking of 3 SPW with Mg2+ resulted in higher copper and nickel grades compared to all other synthetic plant water conditions tested in this study.

The Effect of Metallic and Ionic Species on the Performance of a Biological Effluent Treatment System

1977 ◽  
Vol 12 (1) ◽  
pp. 191-212
Author(s):  
B. Volesky ◽  
Q. Samak ◽  
P. Waller
Keyword(s):  
Activated Sludge ◽  
Inorganic Ions ◽  
Industrial Effluents ◽  
Original Data ◽  
Ionic Species ◽  
Threshold Concentration ◽  
Effluent Treatment ◽  
Organic Load ◽  
Metallic Ions ◽  
Activated Sludge Systems

Abstract Review of the available results appearing in the recent literature is presented focusing particularly upon the effects of metallic ions such as Cr, Cu, Zn, Cd, Hg, V, Zn, Ni and Co. Some original data involving the effects of Na are presented and discussed. Development of parameters used in evaluating the influence of toxic or inhibitory species on the mixed microbial population of an activated sludge system is of crucial importance and different techniques employed such as BOD-COD-TOC-removal rates, Oxygen Uptake Rate, and others are discussed, showing relative inadequacy of currently applied assays. From the data available, certain trends can be discerned. There is a definite threshold concentration for each metallic ion, depending on the organic load of the feed. In the order of increasing toxicity to activated sludge systems reflected in lower BOD removals the following metals have been listed as inhibiting factors at concentrations starting from 1 ppm applied on a continuous basis: hexavalent chromium, cobalt, zinc, cadmium, trivalent chromium, copper and nickel. Metals in combination have not been reported to exhibit any significantly different effects as compared to those observed with individually introduced metallic ions. Tolerance of some activated sludge systems to shock loadings by various inorganic ions and metals is reviewed. The conclusions are of particular importance for estimating the performance of biox systems handling industrial effluents which are likely to contain toxic components of inorganic or metallic nature.

scholarly journals Probing the Effect of Water Recycling on Flotation through Anion Spiking Using a Low-Grade Cu–Ni–PGM Ore: The Effect of NO3−, SO42− and S2O32−

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 340
Author(s):  
Mathew Dzingai ◽  
Malibongwe S. Manono ◽  
Kirsten C. Corin
Keyword(s):  
Water Chemistry ◽  
Froth Flotation ◽  
Water Source ◽  
Threshold Concentration ◽  
Process Water ◽  
Low Grade ◽  
Unit Operations ◽  
Flotation Performance ◽  
Anion Distribution ◽  
Nickel Grade

Water scarcity necessitates the recycling of process water within mineral processing practices. This may however come with its disadvantages for unit operations such as froth flotation as this process is water intensive and sensitive to water chemistry. It is therefore important to monitor the water chemistry of the recycle stream of process water and any other water source to flotation. Monitoring the concentrations of the anions in recycled process water is therefore important to consider as these are speculated to impact flotation performance. Batch flotation tests were conducted using synthetically prepared plant water (3 SPW) with a TDS of 3069 mg/L as the baseline experiment. 3 SPW contained 528 mg/LNO3− and 720 mg/L SO42−, other anions and cations, and no S2O32−. Upon spiking 3 SPW with selected anions, viz, NO3−, SO42− and S2O32−, it was noted that NO3− and SO42− exhibited threshold concentrations while S2O32− did not show a threshold concentration for both copper and nickel grade. Spiking 3 SPW with 352 mg/L more of NO3− to a total 880 mg/L NO3− concentration resulted in the highest copper and nickel grade compared to 3 SPW while increasing the S2O32− from 60 to 78 mg/L increased nickel and copper grade. 720 to 1200 mg/L SO42− and 528 to 880 mg/L NO3− were deemed the concentration boundaries within which lies the threshold concentration above which flotation performance declines with respect to metal grades, while for S2O32− the threshold concentration lies outside the range considered for this study. Anion distribution between the pulp and the froth did not seem to impact the recovery of copper or nickel. Notably, the correlation between the concentrate grades and anion distribution between the froth and the pulp seemed to be ion dependent.

scholarly journals Specific Ion Effects on the Behavior of Mixtures of Sodium Iso-Butyl Xanthate and Sodium Diethyl Dithiophosphate during the Flotation of a Cu-Ni-PGM Ore: Effects of CaCl2 and NaCl

2021 ◽  
Vol 6 (1) ◽  
pp. 22
Author(s):  
Malibongwe S. Manono ◽  
Katlego Matibidi ◽  
Kirsten C. Corin ◽  
Catherine K. Thubakgale ◽  
Iyiola O. Otunniyi ◽  
...  
Keyword(s):  
Froth Flotation ◽  
Monovalent Cation ◽  
Process Water ◽  
Polyvalent Cation ◽  
Flotation Reagents ◽  
Sulfide Flotation ◽  
Froth Stability ◽  
Ion Effects ◽  
The Relationship ◽  
Diethyl Dithiophosphate

Inorganic electrolytes present in the process water used during froth flotation may have both beneficial and detrimental effects. These effects are said to be ion specific, as some ions may result in enhanced froth stability, increased mineral recoveries and decreased concentrate grades, while others may bring the opposite effects. Onsite process water quality variations have intensified the need to understand the relationship between inorganic electrolytes and flotation reagents on flotation performance. The use of mixtures of thiol collectors in sulfide flotation is a common practice across the globe; however, very few investigations have considered these in process waters of varying compositions. This study considers the effect of common cations, Na+ and Ca2+, in process water on the behavior of mixtures of thiol collectors. Single-salt solutions of NaCl and CaCl2 at an ionic strength of 0.0213 mol·dm−3 were used to investigate the behavior of mixtures of two thiol collectors. These were carefully selected to understand how mixtures of thiol collectors behave in the presence of a monovalent cation versus a polyvalent cation. Bench-scale froth flotation tests were conducted using a Cu-Ni-PGM ore from the Merensky Reef. The results have shown that the divalent cation, Ca2+, resulted in higher %Cu and %Ni recoveries at all collector mixtures compared to the monovalent cation, Na+. The concentrate grades were, however, slightly compromised, as slightly more gangue reported to the concentrate in the presence of Ca2+. This behavior is attributed to the effect of polyvalent cations on bubble coalescence and froth stability.

scholarly journals Review of the Main Factors Affecting the Flotation of Phosphate Ores

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1109
Author(s):  
Manar Derhy ◽  
Yassine Taha ◽  
Rachid Hakkou ◽  
Mostafa Benzaazoua
Keyword(s):  
Zeta Potential ◽  
Aqueous Solutions ◽  
Treatment Process ◽  
Froth Flotation ◽  
Main Constituent ◽  
Full Understanding ◽  
Factors Affecting ◽  
Froth Stability ◽  
Main Factors ◽  
Phosphate Ores

The way to successfully upgrade a phosphate ore is based on the full understanding of its mineralogy, minerals surface properties, minerals distribution and liberation. The conception of a treatment process consists of choosing the proper operations with an adequate succession depending on the ore properties. Usually, froth flotation takes place in phosphate enrichment processes, since it is cheap, convenient, and well developed. Nevertheless, it is a complex technique as it depends on the mineral’s superficial properties in aqueous solutions. Aspects such as wettability, surface charge, zeta potential, and the solubility of minerals play a basic role in defining the flotation conditions. These aspects range from the reagents type and dosage to the pH of the pulp. Other variables namely particles size, froth stability, and bubbles size play critical roles during the treatment, as well. The overall aim is to control the selectivity and recovery of the process. The following review is an attempt to add to previous works gathering phosphate froth flotation data. In that sense, the relevant parameters of phosphate ores flotation are discussed while focusing on apatite, calcite, dolomite, and quartz as main constituent minerals.

scholarly journals Producing Safe Drinking Water Using an Atmospheric Water Generator (AWG) in an Urban Environment

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2940
Author(s):  
Offir Inbar ◽  
Igal Gozlan ◽  
Stanislav Ratner ◽  
Yaron Aviv ◽  
Roman Sirota ◽  
...  
Keyword(s):  
Drinking Water ◽  
Urban Environment ◽  
Water Scarcity ◽  
New Technologies ◽  
Sampling Site ◽  
Inorganic Ions ◽  
Safe Drinking Water ◽  
Atmospheric Water ◽  
Alternative Source ◽  
Dew Water

Alternative new technologies are urgently needed to overcome the rapidly increasing global water scarcity. Atmospheric dew water is a potential source of potable water, as the earth’s atmosphere contains billions of tons of fresh water (98% in a vapor state). The atmospheric water generator (AWG) converts water vapor into liquid water and is a promising solution for water scarcity. We provide the first comprehensive analysis of the chemical profiles of water produced for several months by an AWG in the city of Tel Aviv, Israel. Metals, inorganic ions, volatile organic compounds (VOCs), and semi-VOCs were analyzed in the dew water. The main elements found were ammonium, calcium, sulfate, and nitrate. Location of the sampling site in an urban residential area, between major traffic routes, likely affected the chemical composition of the produced dew water. Nevertheless, the produced water nearly always (day and night in different seasons) met the WHO and Israeli drinking water standards. Thus, even in a highly developed urban environment, the AWG offers an excellent alternative source of safe drinking water throughout the year.

scholarly journals Village-Scale Electrodialysis Desalination: Field Trial Validation

2017 ◽  
Author(s):  
Natasha C. Wright ◽  
Amos G. Winter
Keyword(s):  
Water Quality ◽  
Field Trial ◽  
Design Methodology ◽  
Specific Energy Consumption ◽  
Cost Effective ◽  
Experimental Results ◽  
Water Recovery ◽  
Research Facility ◽  
High Recovery ◽  
Product Water

This paper presents the design and initial testing of a village-scale photovoltaic (PV) powered electrodialysis reversal (EDR) desalination system for rural India. The system was built by the authors and tested at the Brackish Groundwater National Desalination Research Facility in New Mexico. EDR has the potential to be more cost effective than currently installed village-scale reverse osmosis (RO) systems in off-grid locations due to the lower specific energy consumption of EDR versus RO at high recovery ratios. Lower energetic demand leads to lower solar power system costs for off-grid areas. The system tested in this study is designed to validate that energetic, product water quality, and water recovery requirements can be met. An analytical model of the system that accounts for the composition of natural groundwater is presented and compared to initial experimental results. Additionally, results from the USAID Desal Prize are presented showing the system’s performance in regards to recovery ratio and product water quality. This paper presents the design methodology, resulting system parameters, and experimental results for an initial village-scale PV-EDR field trial.

scholarly journals Comparative assessment of managed aquifer recharge versus constructed wetlands in managing chemical and microbial risks during wastewater reuse: a review

2013 ◽  
Vol 4 (1) ◽  
pp. 1-8 ◽  
Author(s):  
A. F. Hamadeh ◽  
S. K. Sharma ◽  
G. Amy
Keyword(s):  
Water Quality ◽  
Constructed Wetlands ◽  
Wastewater Reuse ◽  
Cost Effective ◽  
Managed Aquifer Recharge ◽  
Water Recovery ◽  
Aquifer Recharge ◽  
Natural Treatment Systems ◽  
Natural Treatment ◽  
Pre Treatment

Constructed wetlands (CWs) and managed aquifer recharge (MAR) represent commonly used natural treatment systems for reclamation and reuse of wastewater. However, each of these technologies have some limitations with respect to removal of different contaminants. Combining these two technologies into a hybrid CW-MAR system will lead to synergy in terms of both water quality and costs. This promising technology will help in the reduction of bacteria and viruses, trace and heavy metals, organic micropollutants, and nutrients. Use of subsurface flow CWs as pre-treatment for MAR has multiple benefits: (i) it creates a barrier for different microbial and chemical pollutants, (ii) it reduces the residence time for water recovery, and (iii) it avoids clogging during MAR as CWs can remove suspended solids and enhance the reclaimed water quality. This paper analyzes the removal of different contaminants by CW and MAR systems based on a literature review. It is expected that a combination of these natural treatment systems (CWs and MAR) could become an attractive, efficient and cost-effective technology for water reclamation and reuse.

scholarly journals Econometrics of Stated Preferences

2019 ◽  
Author(s):  
Denzil G. Fiebig ◽  
Hong Il Yoo
Keyword(s):  
Stated Preference ◽  
Research Question ◽  
Effective Means ◽  
Revealed Preference ◽  
Cost Effective ◽  
Discrete Choice Experiments ◽  
Alternative Source ◽  
Preference Data ◽  
Stated Preference Methods ◽  
Realistic Situation

Stated preference methods are used to collect individual-level data on what respondents say they would do when faced with a hypothetical but realistic situation. The hypothetical nature of the data has long been a source of concern among researchers as such data stand in contrast to revealed preference data, which record the choices made by individuals in actual market situations. But there is considerable support for stated preference methods as they are a cost-effective means of generating data that can be specifically tailored to a research question and, in some cases, such as gauging preferences for a new product or non-market good, there may be no practical alternative source of data. While stated preference data come in many forms, the primary focus in this article is data generated by discrete choice experiments, and thus the econometric methods will be those associated with modeling binary and multinomial choices with panel data.

scholarly journals α-amylase from white pitaya (Hylocereus undatus L.) peel: optimization of extraction using full factorial design

2021 ◽  
Vol 9 (1) ◽  
pp. 79-86
Author(s):  
Zahra Shad ◽  
Hamed Mirhosseini ◽  
Mahsa Motshakeri ◽  
Mohammad Reza Sanjabi ◽  
Anis Shobirin Meor Hussin
Keyword(s):  
Factorial Design ◽  
Specific Activity ◽  
Mixing Time ◽  
Cost Effective ◽  
Extraction Process ◽  
Full Factorial Design ◽  
Alternative Source ◽  
Sodium Phosphate Buffer ◽  
Hylocereus Undatus ◽  
Full Factorial

Introduction. Amylase is a significant enzyme with numerous commercial applications, which is largely used to convert starches into oligosaccharides. Extraction of amylase from plant by-products or cheap sources is cost-effective. Annually, pitaya fruit juice industry produces huge amounts of peels that could be utilized as an alternative source in enzyme production industry. The work aimed to examine and optimize extraction process. Study objects and methods. In this study, we investigated parameters of extraction to optimize the process, as well as activity of α-amylase from white pitaya fruit (Hylocereus undatus L.) peel. For this purpose, a two-level full factorial design was applied. Three variables, namely the pH of sodium phosphate buffer (X1, 4.5–7.5), mixing time (X2, 1–3 min), and a sample-to-buffer ratio (X3, 1:3–1:5), were used to identify significant effects and interactions within the samples. Results and discussion. The results demonstrated that the buffer pH had the most significant (P ≤ 0.05) effect on total amylase activity. Based on full factorial design analysis, we revealed the optimal conditions for amylase enzyme extraction ‒ pH of 6, mixing time of 2 min, and a sample-to-buffer ratio of 1:4. Lower and higher values influenced adversely on specific activity of amylase. Conclusion. Optimization increased the enzyme specific activity by a factor of 4.5. Thus, pitaya peel could be used in different industries as a rich natural α-amylase source.

scholarly journals Detection of Helminth Ova in Wastewater Using Recombinase Polymerase Amplification Coupled to Lateral Flow Strips

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 691
Author(s):  
Vivek B. Ravindran ◽  
Basma Khallaf ◽  
Aravind Surapaneni ◽  
Nicholas D. Crosbie ◽  
Sarvesh K. Soni ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Cost Effective ◽  
Lateral Flow ◽  
Recombinase Polymerase Amplification ◽  
Detection Methods ◽  
Water Current ◽  
Recycled Water ◽  
Lateral Flow Strip ◽  
Skilled Personnel

Ascaris lumbricoides is a major soil-transmitted helminth that is highly infective to humans. The ova of A. lumbricoides are able to survive wastewater treatment, thus making it an indicator organism for effective water treatment and sanitation. Hence, Ascaris ova must be removed from wastewater matrices for the safe use of recycled water. Current microscopic techniques for identification and enumeration of Ascaris ova are laborious and cumbersome. Polymerase chain reaction (PCR)-based techniques are sensitive and specific, however, major constraints lie in having to transport samples to a centralised laboratory, the requirement for sophisticated instrumentation and skilled personnel. To address this issue, a rapid, highly specific, sensitive, and affordable method for the detection of helminth ova was developed utilising recombinase polymerase amplification (RPA) coupled with lateral flow (LF) strips. In this study, Ascaris suum ova were used to demonstrate the potential use of the RPA-LF assay. The method was faster (< 30 min) with optimal temperature at 37 °C and greater sensitivity than PCR-based approaches with detection as low as 2 femtograms of DNA. Furthermore, ova from two different helminth genera were able to be detected as a multiplex assay using a single lateral flow strip, which could significantly reduce the time and the cost of helminth identification. The RPA-LF system represents an accurate, rapid, and cost-effective technology that could replace the existing detection methods, which are technically challenged and not ideal for on-site detection in wastewater treatment plants.

Sign in / Sign up

Export Citation Format

Share Document