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Performance of point-of-use devices to remove manganese from drinking water

Authors:
Annie Carrière at Polytechnique Montréal
Annie Carrière
Manon Brouillon
Manon Brouillon
Manon Brouillon
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Sébastien Sauvé at Université de Montréal
Sébastien Sauvé
Maryse Bouchard at National Institute of Scientific Research
Maryse Bouchard
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Abstract and Figures

A recent epidemiological study reported significant cognitive deficits among children in relation with consumption of water with manganese concentrations in the order of 50-100 ug/L. Concerns for neurotoxic effects of manganese raises the need for evaluating the efficiency of domestic water treatment systems for removal of this metal. The objective of the present study was to determine whether POU devices are efficient at reducing dissolved manganese concentration in drinking water. Various devices were tested according to the NSF 53 protocol for general metals for high pH test water. Based on these assays, the pour-through filters were identified as the most promising POU devices, with dissolved manganese removal greater than 60% at 100% rated capacity, and greater than 45% at 200% rated capacity (influent Mn ≈1,000 μg/L). Under-the-sink filters using cationic exchange resins (i.e., water softeners) were also efficient at removing dissolved manganese but over a shorter operating life. Manganese leaching was also observed beyond their rated capacity, making them less robust treatments. The activated carbon block filters and other proprietary technologies were found to be inappropriate for dissolved manganese removal. Further evaluation of POU devices performance should evaluate the impact of hardness on process performance. The impact of particulate Mn should also be evaluated.
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1
1
Performance of an hybrid
membrane process using
biological PAC
Benoit Barbeau, Simon Léveillé, Sébastien
Charest and Annie Carrière
École Polytechnique de Montréal
Alain Gadbois
John-Meunier Inc. – Veolia
Membrane Technology conference, March 28, 2011
2
Background
At the end of the 1990s, nanofiltration (NF) was
seen as the most promising technology for
drinking water treatment.
This process has not been as largely adopted due :
Energy costs
Fouling issues (requires a pretreatment)
Hybrid membrane processes integrating both PAC
adsorption and low pressure membranes (UF or
MF) offers an alternative to NF.
3
Integrating activated carbon with
membranes: the North American experience
Ultra(Micro)filtration + O3+ GAC filters examples:
Twin Oaks, CA (2007): 400 MLD
•UF + O3+ GAC
Lakeview,Ont. (2008): 363 MLD
•O3+ BAC + UF
Filters are expensive to build
PAC is more efficient than GAC
Integrating PAC with UF is therefore
of great interest
Twin Oaks
Lakeview
Source: Ge-Zenon
Source: Ge-Zenon
4
Immersed membrane configuration
The challenge of fouling
What are the impacts of operating
conditions on fouling and process
performance ?
Can the process be operated in
biological mode, i.e. leaving the PAC
in the reactor?
5
Project description
PHASE 1: Mini-Pilot PAC bioreactors (1 L) fed
during 160 days with filtered-ozonated
surface waters (2007-2009)
Impact of PAC concentration
Impact of PAC diameter
PHASE 2: Industrial pilot (50 m3/d) (2009-ongoing)
Settling + Ozonation + PAC/immersed UF
Impact of flux on fouling
Performance for NH3, THM, BDOC
6
Phase 1: Mini-pilot study
Description of the bioreactors
Effluent
Influent (ozonated filtered water)
Purge
Effluent
Stirred 1-L
bioreactor
10 µm sieve
7
Under stable biological mode (100-160 d of operation)
Increasing PAC concentration from 5 to 25 g/L significantly
increased performance.
Average performance: Reduction of 9%, 43% & 93% of DOC,
BDOC and NH3 using 25g/L of PAC
Equal perfomance using a PAC of 25 µm or 200 µm.
Increasing contact time over 30 min does not significantly
improve performance.
Biological PAC tends to form agregates
Phase 1: Mini-pilot study
Main conclusions
8
1: Settling (Actiflo®) (8 feet)
1 2 34
2: Ozonation: 1.5 mg O3/L (8 feet)
3: Pressurised HMP (Opaline S®) (12 ft)
4: Immersed HMP (Opaline B®)(10 ft)
Phase 2: Industrial Pilot
Description
9
Puronmembrane
Hollow fiber (PES)
Porosity: 0.05µm(ultrafiltration)
Membranearea: 10m²
Configuration: Immersed
PICAHYDROLP39
(Woodbase)
Size: D50 :18.7microns
Type:
Membranesspecifications
Technology:
PACspecifications
Flux: 15to25LMH
Concentration: 10‐12g/L
Phase 2: Industrial Pilot
Bioreactor specifications
300LMH
Aeration rate:
5minfiltration+
1minbackwash
Filtrationcycle:
Backwash rate: 30LMH
Pretreatment: Sludge blanket clarifier
10
Research Objectives
Evaluate the viability of the Opaline-B
operated under biological mode
-Two parallel reactors
With or without PAC
-Side comparison with the existing plant
Pilot located at the Ste-Rose WTP
Settling + Filtration + Ozone + BAC filters
Source water: High TOC (6-8), ammonia (200-
300 ppb), E. coli = 100-500 CFU/100mL
11
Pilot Plant Study
Experimental phases
Date PAC age [PAC] Flux
(L/m2/h) Comments
Phase
I
13july‐
19oct. 2009 0‐ 120d20g/L 45 à15 Excessivefouling
Phase
II
18Feb.‐
4May2010 200‐ 280 d 12g/L 15à25 New membranes
Phase
III
13May‐
ongoing
Fixed:
‐30 d
‐60d
10g/L 25
Same membranes
New PAC
12
0
10
20
30
40
50
0 0.5 1.0 1.5 2.0 2.5
Flux(L/m2/h)
Transmembrane presssure (psi)
Selection of the Operating Flux
Technique used: « flux stepping »
0
100
200
300
08:30 09:30
Flux stepping
heure
Flux (L/h)
36
25
The presence of biological PAC reduces the critical flux.
Opaline w/o PAC Membrane w/o PAC
Opaline with PAC
13
Critical Flux
W/O PAC: 36 LMH at 7 oC (48 LMH at 20 oC)
With PAC: 25 LMH at 7 oC (37 LMH at 20 oC)
Selected Flux:
Initially 15 LMH; increase to 25 LMH
5 min filtration + 1 min backpulse at 30 LMH
Available Hydraulic Residence Time
92 min at 15 LMH
55 min at 25 LMH
Selection of the Operating Flux (cntd)
14
Results:
Permeability
0
100
200
300
400
500
600
700
800
900
1000
Operating days
with PAC
w/o PAC
15LMH
CIP CIP
Permeability @20oC
(LMH/bar)
15
Results:
Suspended Solids inside the Bioreactor
0
2
4
6
8
10
12
14
16
18
20
MES(g/L)
OpalineavecCAP
MembranesansCAP
Phase II Phase III
Physical
cleaning
PAC
dosing
Physical
cleaning
+3 g/L
with PAC
without PAC
16
Physical fouling
MinimalPAC
accumulation,mainly
at thelower endof
themodule
Theairinjectionat the
bottom minimizes PAC
settling
17
Chemical cleaning efficiency
Flux test for new membrane and after chemical cleanings
-3,50
-3,00
-2,50
-2,00
-1,50
-1,00
-0,50
0,00 0 20406080
TMP (psi)
Normalized flux @20C (LMH)
CW-new
CAP 200d-new
CW-3months
CAP 0d-3months
CW-6months
-3,50
-3,00
-2,50
-2,00
-1,50
-1,00
-0,50
0,00 0 20406080
TMP (psi)
Normalized flux @20C (LMH)
CW-new
CW-3months
CW-6months
Membrane with CAP Membrane W/O CAP
18
Process performance
Ammonia
NH4+removal (%)
0
20
40
60
80
100
Phase II Phase III
[NH4+] affluent:
50 to 300 µg/L
1 to 15 oC15 to 30 oC
Opaline(with CAP)
Membrane(w/oCAP)
BACeffluent
19
Hypothesis for nitrification decline
Increase metals content of PAC
Old PAC - 240 DAYS
PAC - Virgin
Aluminium
Calcium
Fer
Carbone
Autre(O,N,P,S)
Iron
Others
Alum flocs accumulation may inhibit nitrification
20
PAC texture changed over time. This may hinder O2and/or
NH4+diffusion to AOB.
Biological
PAC New
PAC
Hypothesis for nitrification decline
PAC floculation/agregation
21
Process performance
Dissolved organic carbon (DOC)
1,0
1,5
2,0
2,5
3,0
3,5
DOC(mg/L)
Phase II Phase III
1 to 15 oC15 to 30 oC
Affluentpilot
AffluentBAC
No pilot O3
Membrane(w/oCAP)
Opaline(with CAP)
BACeffluent
22
Process performance
BDOC
Phase II Phase III No pilot O3
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
0,90
1,00
BDOC(mg/L)
AffluentBAC
Affluentpilot
Opaline(with CAP)
Membrane(w/oCAP)
BACeffluent
23
Uniform formation conditions (UFC)
Cl2res. = 1ppm @ 24h; pH=8; T=22oC
Process performance
THMs
Sampling campaign
THM–UFC(µg/L)
8 may 10
20 feb.10
20 jul. 09
0
10
20
30
40
50
60
70
80
90
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
No pilot O3
AffluentBAC
Affluentpilot
Opaline(with CAP)
BACeffluent
Membrane(w/oCAP)
Phase II Phase III
Phase I
24
0
5
10
15
20
25
30
THM/DOC (µg/mg)
DOC
2.74 DOC
2.62
DOC
2.24 DOC
2.63 DOC
2.25
Process performance
Specific THM formation
Despite lower
DOC levels,
the reactivity
of the
accumulated
OM is greater
(21 vs 15 µg/mg)
W/O PAC
With PAC
Influent Effluent
Influent
Full-scale
BAC
Membrane
bioreactors
25
Conclusions
Combining biological PAC with UF
Lowered the critical flux by 30%
Caused reversible fouling which requires attention
(cleaning and thoughtful aeration…) and irreversible
fouling
However, filtration cycles >3 months at 25 LMH
Allowed complete nitrification at 6oC as long as the
PAC is not too old (or too much contaminated by alum
flocs carry over)
Provided equivalent or better water quality than the
plant (DOC, BDOC, THM) (both 30d and 60d)
Allowed for more operation flexibility (adsorption vs
biodegradation)
26
Conseil de recherches en sciences
naturelles et en génie du Canada
www.polymtl.ca/chaireeau

Supplementary resource (1)

Carriere2011 PerformanceOfPointOfUseDevicesToRemoveManganeseFromDrinkingWater
Data
November 2013
Benoit Barbeau · Sébastien Sauvé · Brouillon M. · Annie Carrière · Maryse Bouchard
... Furthermore, Mn 2+ ions are considered neurotoxic agents, and long-term environmental exposure is a supposed accelerator of the onset of Parkinson's disease [2]. Recent epidemiological studies concerning the consumption of water with Mn 2+ concentrations on the order of 50-100 µg L −1 reported significant cognitive deficits among children [3]. From the operational point of view, Mn 2+ causes incrustations in pipelines at concentrations > 0.02 mg L −1 [4] and is an undesirable nutrient substrate for the development of bacteria in water distribution networks [5]. ...
... where C 0 and C e are the initial and equilibrium solution concentrations of Mn (mg L −1 ), respectively, V is the solution volume (L), and m is the mass of the adsorbent (g). The data obtained from the adsorption isotherm experiments were fitted to the Langmuir (2) and Freundlich (3) models given by the adapted equations as follows (2,3): ...
Removal of manganese by adsorption onto newly synthesized TiO 2 -based adsorbent during drinking water treatment
Article
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  • Oct 2021
Manganese is naturally present in water, but its increased concentration in potable water is undesirable for multiple reasons. This study investigates an alternative method of demanganization by a newly synthesized TiO2-based adsorbent prepared through the transformation of titanyl sulphate monohydrate to amorphous sodium titanate. Its adsorption capacity for Mn²⁺ was determined, while a range of influential factors, such as the effect of contact time, adsorbent dosage, pH value, and added ions was evaluated. The adsorbent appeared highly effective for Mn²⁺ removal owing to its unique characteristics. Besides adsorption via electrostatic interactions, ion-exchange was also involved in the Mn²⁺ removal. Although the Mn²⁺ removal occurred within the whole investigated pH range of 4–8, the maximum was achieved at pH 7, with qe = 73.83 mg·g⁻¹. Equilibrium data revealed a good correlation with Langmuir isotherm in the absence of any ions or in the presence of monovalent co-existing ions, while the results in the presence of divalent co-existing ions showed a better fit to Freundlich isotherm. Additionally, the presence of monovalent cations (Na⁺, K⁺) only slightly decreased the Mn²⁺ removal efficiency as compared to divalent cations (Ca²⁺, Mg²⁺) that caused a greater decrease; however, the effect of anions (Cl⁻, SO4²⁻) was insignificant. To provide insight into the adsorbent safety, the toxicity assessment was performed and showed no harmful effect on cell activity. Furthermore, the residual concentration of titanium after adsorption was always below the detection limit. The results imply that the synthesized TiO2-based adsorbent is a safe promising alternative method for demanganization.
View
... A large percentage of the population is not convinced about the quality of tap water supplied by local water treatment plants. As a result, people are increasingly choosing to use home water purification methods [8][9][10][11]. To improve the quality of tap water, due to the low price and ease of use, consumers most often decide to buy free-standing filter jugs. Their use does not require a connection to the water supply system, which is a great advantage for many users [12][13][14]. ...
Clean and Tasty Water - Analysis of the Effectiveness of Water Filter Jugs
Conference Paper
Full-text available
  • Jan 2024
The article evaluates the effectiveness of jug filters in terms of improving the quality of drinking water. Changes in chemical and bacteriological parameters of tap water filtered with jugs from three different manufacturers were analyzed. Organoleptic parameters of filtered water, that is color, turbidity, odor, taste and selected chemical parameters: pH, conductivity, total hardness, chlorine content, total organic carbon, nitrogen, and phosphorus compounds were examined. The assessment of the microbiological quality and sanitary safety of the filtered water was based on changes in the total number of bacteria (samples were inoculated simultaneously on A and R2A agar and incubated at 37 ℃ and 22 ℃) and by bioluminescence analysis (Adenosine triphosphate measurement). The obtained test results were discussed and compared with the declarations of the manufacturers of jug filters. The stability and risk of losing the safety of the filtered water were also assessed.
View
... However, unlike NSF-53 certified pour-through POU devices, NSF-42 certified devices are not rated for the removal of particulates <30 µm in size (highest level of NSF-52 certification observed for particle removal using pour-through POU devices is class 5, i.e., the removal of particles >30-50 µm), as particles <30 µm are likely to pass directly into filtered water [14]. Previous studies have evaluated common POU devices that achieve NSF-53 and NSF-42 certification standards for the removal of dissolved (≤0.45 µm [14][15][16][17]) and particulate matter (0.45-1 µm; [13]); however, the removal of MP particles has not been specifically addressed. ...
Microplastic Removal from Drinking Water Using Point-of-Use Devices
Article
Full-text available
  • Mar 2023
The occurrence of microplastics in drinking water has drawn increasing attention due to their ubiquity and unresolved implications regarding human health. Despite achieving high reduction efficiencies (70 to >90%) at conventional drinking water treatment plants (DWTPs), microplastics remain. Since human consumption represents a small portion of typical household water use, point-of-use (POU) water treatment devices may provide the additional removal of microplastics (MPs) prior to consumption. The primary objective of this study was to evaluate the performance of commonly used pour-through POU devices, including those that utilize combinations of granular activated carbon (GAC), ion exchange (IX), and microfiltration (MF), with respect to MP removal. Treated drinking water was spiked with polyethylene terephthalate (PET) and polyvinyl chloride (PVC) fragments, along with nylon fibers representing a range of particle sizes (30-1000 µm) at concentrations of 36-64 particles/L. Samples were collected from each POU device following 25, 50, 75, 100 and 125% increases in the manufacturer's rated treatment capacity, and subsequently analyzed via microscopy to determine their removal efficiency. Two POU devices that incorporate MF technologies exhibited 78-86% and 94-100% removal values for PVC and PET fragments, respectively, whereas one device that only incorporates GAC and IX resulted in a greater number of particles in its effluent when compared to the influent. When comparing the two devices that incorporate membranes, the device with the smaller nominal pore size (0.2 µm vs. ≥1 µm) exhibited the best performance. These findings suggest that POU devices that incorporate physical treatment barriers, including membrane filtration, may be optimal for MP removal (if desired) from drinking water.
View
... The results have shown manganese concentration removal of 90%. Carrière et al. (2011) performed a study where point-of-use devices were utilized for the removal of manganese from potable water. The results indicated manganese removal efficiency of greater than 60% through the utilization of pour-through filters. ...
Challenges, advances and sustainabilities on the removal and recovery of manganese from wastewater: A review
Article
  • Sep 2022
  • J CLEAN PROD
Wastewater matrices rich in manganese triggers severe and disastrous ecological impairments to different spheres of the receiving environments. This is attributed to the degree, magnitude, and extent of its eco-toxicological impacts to living organisms on exposure. In this review, insights into the sources of manganese, relative eco-toxicological concerns, treatment options, and their significance in light of future perspectives and outlooks are meticulously discussed and elucidated. Potential avenues for manganese recovery from wastewater streams, their sustainabilities, and economic benefit are also unpacked. Furthermore, gross challenges of practicing circular economy in manganese recovery are also highlighted. This review explicitly demonstrated viable ways for prudent and pragmatic management of manganese in industrial effluents and further afield. Henceforth, ecological disparities that comprise fierce environmental footprints of manganese could be curtailed, averted, and ameliorated through enacting and inspiring the well-known circular economy and waste beneficiation concepts. Finally, future perspectives, outlooks, and avenues for in-depth appraisal are duly underscored and distilled.
View
... As of 2019, Canada has introduced a health-based regulation of Mn (0.12 mg/L) due to increasing evidence of manganese neurotoxicity, especially for infants and children ( [7,8]; Health [9]). Currently, POE catalytic filtration with intermittent regeneration or POE cationic ion exchange (IX) coupled with point-of-use reverse osmosis are two of the most common domestic installations to remove Mn [10]. In an effort to address the shortcomings of these methods (such as the risk of Mn leaching and the high consumption of salts and production of spent brine), we previously proposed an alternative Mn removal method using a novel back-washable hollow fiber nanofiltration (HFNF) membrane [11]. ...
Improving remineralization and manganese-removal of soft waters using a mixed CaCO3/MgO contactor
Article
  • Oct 2022
The aim of this study was to investigate the role of MgO on the long-term operation of a mixed media contactor. Specifically, the simultaneous removal of aqueous manganese and the remineralization of soft waters using pure calcite are limited by a remineralization breakthrough after 600 h of operation in the presence of high Mn concentrations (5 mg Mn/L). The introduction of as little as 5 % (m/m) MgO was able to improve the Mn removal kinetic, while maintaining remineralization objectives over 720 h of operation. After treating elevated concentrations of Mn, both media exhibited a Mn-coated layer which contributed to limiting the mass transfer from the media core to the liquid phase. X-ray photoelectron spectroscopy (XPS) identified this superficial layer as 10 % Mn oxides (MnOx) on MgO media compared to 1.4 % MnOx on calcite, suggesting the MgO acts as the preferred reaction surface during Mn removal. Therefore, it is postulated that in the presence of MgO, Mn removal is impacted by high pH conditions (pH = 10.5) which introduces a significant precipitation mechanism as Mn²⁺ is oxidized. For all the examined conditions, the formation of this coating improved Mn removal due to the autocatalytic nature of the adsorption/oxidation of dissolved manganese by MnOx. MgO is therefore thought to contribute to a complex sorption-coprecipitation process in the operation of a mixed media contactor.
View
... As of 2019, Canada has introduced a health-based regulation of Mn (0.12 mg/L) due to increasing evidence of manganese neurotoxicity, especially for infants and children ( [7,8]; Health [9]). Currently, POE catalytic filtration with intermittent regeneration or POE cationic ion exchange (IX) coupled with point-of-use reverse osmosis are two of the most common domestic installations to remove Mn [10]. In an effort to address the shortcomings of these methods (such as the risk of Mn leaching and the high consumption of salts and production of spent brine), we previously proposed an alternative Mn removal method using a novel back-washable hollow fiber nanofiltration (HFNF) membrane [11]. ...
View
Mini-Cores of Activated Carbon Block Simulate Full-sized Performance for Removing Organics and Arsenate from Drinking Water
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Activated carbon block (ACB) filters are widely used in point-of-use (POU) drinking technology to remove tastes, odors, and organic compounds from drinking water, and when modified can even remove inorganic pollutants (e.g., arsenate, lead, copper). To introduce ACB technologies to the POU market, thorough assessment and testing are required to meet the National Sanitary Foundation 53 certification. Testing to gain this certification can be costly and time-consuming and is usually only done on the final product before commercial distribution. We developed and explored how a cylindrical “plug” cored from an ACB can be used in a mini-core apparatus with low water volumes, to mimic full-sized ACB performance. These mini-cores allow the same outside-in radial flow conditions as the full-sized ACB. After addressing potential hydraulic channeling problems, tests with chloroform or arsenate confirmed the ability of the mini-core ACB “plugs” to mimic the performance of full-sized cartridge unit. The benefit of the mini-core ACB “plug” lab-scale approach lays the foundation for testing methodologies that can evaluate a range of pollutants, water chemistries, or material modifications using a small fraction of water compared to full-sized ACB filter. Overall, the development of a mini-core ACB testing apparatus is a key advancement towards sustainable water purification, impacting environmental health, resource conservation, and global access to safe water.
View
View
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Small Community Water Systems Have the Highest Prevalence of Mn in Drinking Water in California, USA
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Manganese (Mn) is currently regulated as a secondary contaminant in California, USA; however, recent revisions of the World Health Organization drinking water guidelines have increased regulatory attention of Mn in drinking water due to increasing reports of neurotoxic effects in infants and children. In this study, Mn concentrations reported to California's Safe Drinking Water Information System were used to estimate the potentially exposed population within California based on system size. We estimate that between 2011 and 2021, over 525,000 users in areas with reported Mn data are potentially exposed to Mn concentrations exceeding the WHO health-based guideline (80 μg L-1), and over 34,000 users are potentially exposed to Mn concentrations exceeding the U.S. Environmental Protection Agency health-advisory limit (300 μg L-1). Water treatment significantly decreased Mn concentrations compared to intake concentrations for all system sizes. However, smaller water systems have a wider range and a higher skew of Mn concentrations in finished water than larger systems. Additionally, higher Mn concentrations were found in systems above the maximum contaminant levels for chromium and arsenic. The treatment of these primary contaminants appears to also remove Mn. Lastly, data missingness remains a barrier to accurately assess public exposure to Mn in very small, small, and medium community water system-delivered water.
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Intellectual Impairment in School-Age Children Exposed to Manganese from Drinking Water
Article
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  • Sep 2011
  • ENVIRON HEALTH PERSP
Manganese is an essential nutrient, but in excess it can be a potent neurotoxicant. Despite the common occurrence of manganese in groundwater, the risks associated with this source of exposure are largely unknown. Our first aim was to assess the relations between exposure to manganese from drinking water and children's intelligence quotient (IQ). Second, we examined the relations between manganese exposures from water consumption and from the diet with children's hair manganese concentration. This cross-sectional study included 362 children 6-13 years of age living in communities supplied by groundwater. Manganese concentration was measured in home tap water (MnW) and children's hair (MnH). We estimated manganese intake from water ingestion and the diet using a food frequency questionnaire and assessed IQ with the Wechsler Abbreviated Scale of Intelligence. The median MnW in children's home tap water was 34 µg/L (range, 1-2,700 µg/L). MnH increased with manganese intake from water consumption, but not with dietary manganese intake. Higher MnW and MnH were significantly associated with lower IQ scores. A 10-fold increase in MnW was associated with a decrease of 2.4 IQ points (95% confidence interval: -3.9 to -0.9; p < 0.01), adjusting for maternal intelligence, family income, and other potential confounders. There was a 6.2-point difference in IQ between children in the lowest and highest MnW quintiles. MnW was more strongly associated with Performance IQ than Verbal IQ. The findings of this cross-sectional study suggest that exposure to manganese at levels common in groundwater is associated with intellectual impairment in children.
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Comparative Study on Adsorption of Mn(II) from Aqueous Solutions on Various Activated Carbons
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The adsorption of Mn(II) on indigenously prepared activated carbons (IPAC) from Bombax malabaricum , Pithecelobium dulse , Ipomea batatas and Peltaforum ferraginium have been studied. The effects of various experimental parameters have been investigated using batch adsorption technique. The extent of Mn(II) removal increased with decrease in initial concentration of the Mn(II), particle size of the adsorbent and increased with increase in contact time, amount of adsorbent used and the initial pH of the solution. Adsorption data were modeled using Freundlich and Langmuir adsorption isotherms and first order kinetic equations. The kinetics of adsorption was found to be first order with regard to intra- particle diffusion rate. The results indicate that such carbons could be employed as low cost adsorbents in waste water treatment for the removal of Mn(II).
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Lead removal from tap water using POU devices
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  • Oct 2010
Particulate lead is inadequately considered in lead certification procedures. In 2007, modification of the NSF-53 testing protocol for lead reduction, consisting of the addition of particulate lead in the NSF challenge water, resulted in cancellation of the certification of pour-through point-of-use devices. The results of this study showed that tap-mounted and under-the-sink domestic filtration devices were efficient in removing total lead (both dissolved and particulate) under the NSF reference level of 10 μg/L. However, pour-through domestic filtration devices poorly removed particulate lead, and, as a result, high lead levels remained in effluent water. This lack of efficiency is attributed to the type of filter used in pour-through devices and justifies cancellation of the NSF-53 certification for lead reduction for such devices in 2007. The results of this research also show the importance of selecting appropriate devices for lead reduction, because particulate lead can be released sporadically from lead service lines, premise plumbing, and faucets.
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Common point-of-use (POU) devices that met NSF/ANSI-53 certification standards for lead removal before July 16, 2007, were evaluated for the reduction of lead and other trace metals in drinking water. Systematic testing and evaluation of various POUs focused on particulate and dissolved lead removal efficacy, under conditions different from those addressed in the NSF-53 testing protocol (particle type, water tested, lead levels). Tap-mounted and under-the-sink POUs showed, globally, adequate removal performance, although the NSF threshold value for lead of 10 pg/L was occasionally slightly exceeded. Pour-through POUs failed to remove particulate lead, decreased pH, did not reduce turbidity, and were the least efficient for chlorine removal. Copper removal was effective for any concentration tested, and silver was detected in effluent water. Nitrification did not increase the dissolution of lead particles trapped in the filters.
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Study on the removal of iron and manganese in groundwater by granular activated carbon
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  • Nov 2005
  • DESALINATION
One of the problems related to groundwater is the reddish colour caused by the presence of ferrous and manganese. Initially, this colour cannot be seen but after it has been exposed to the air, the oxidation of groundwater will promote the precipitation of ferrous and manganese. Eventually, the groundwater turns into reddish in colour. Batch test had been carried out to determine the potential and the effectiveness of granular activated carbon (GAC) in removal of ferrous and manganese from water. The test was conducted by mixing certain amount of GAC with 200 mL sample solution and shook for 6 h in room temperature to achieve an equilibrium. The two most common adsorption equations, Freundlich and Langmuir adsorption isotherms, were used in the study to verify the adsorption performance. From interpretation of the equations, the Langmuir adsorption isotherm was found to fit the experimental data better than that of the Freundlich adsorption isotherm. This shows that the relatively high ambient temperature allowed only monolayer adsorption to occur between the adsorbate and adsorbent. According to Langmuir adsorption isotherm’s assumption, the bonding that was established between the adsorbent and adsorbate are chemically bonded which known as chemisorption. In this study, the adsorption capacity of Fe(II) and Mn(II) were 3.6010 and 2.5451 mg/g, respectively. Therefore, the adsorption capacity for Fe(II) was higher than Mn(II). The main factors that contribute to difference adsorption capacity of Fe(II) and Mn(II) onto GAC are due to ionic radius and electronegativity of metal ions.
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Significance and Removal of Manganese in Water Supplies
Article
  • Oct 1960
This article is based on data accumulated by AWWA Task Group 2680 P-Manganese Deposition in Pipelines. Manganese is a common ingredient of impounded water and of many well waters. In public supplies, it causes such difficulties as staining of clothes and plumbing fixtures, “black” water, incrustation of mains, and interferences with the colorimetric chlorine residual test. In industrial supplies, it causes severe economic losses through discoloration of products, specks in finished goods, and reduction of pipeline carrying capacities. Chemical reactions are generally presumed to account for the greater part of the manganese in groundwater; in stored water, manganese builds up by a combination of biologic and chemical processes working simultaneously. It is difficult to obtain clear-cut statements about the economic significance of manganese in water supplies. In spite of this, requests increase yearly for information on how to remove manganese, how much the process will cost, and what method will best suit a specific water supply. This article discusses the reporting of manganese, manganese-reporting organisms, manganese determination, filter media, manganese stabilization, and manganese removal by the zeolite process or by oxidation.
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METHOD 200.5� DETERMINATION OF TRACE ELEMENTS IN DRINKING WATER BY AXIALLY VIEWED INDUCTIVELY COUPLED PLASMA - ATOMIC EMISSION SPECTROMETRY
Article
  • Jan 2003
Chemical Abstract Services Analyte,Abbreviation,Registry Numbers (CASRN) ))))))))))))))))))))))))))))))))))))))))))))))))))))))))))) Aluminum,(Al),7429-90-5
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Adsorption of Cu(II), Cd(II), Zn(II), Mn(II) and Fe(III) ions by tannic acid immobilised activated carbon
Article
  • Jan 2006
  • SEP PURIF TECHNOL
In this study, adsorption of the toxic metal ions onto tannic acid immobilised activated carbon was investigated depending on pH, contact time, carbon dosage, adsorption capacity and adsorption isotherms by employing batch adsorption technique. In the optimum conditions, the percent adsorption of metal ions were determined for Cu(II) (23.5%), Cd(II) (17.8%), Zn(II) (14.0%), Mn(II) (11.3%) and Fe(III) (17.9%) and results were compared with that of the untreated activated carbon. The order of affinity based on uptake by tannic acid immobilised activated carbon and untreated activated carbon was the same as Cu(II)>Fe(III)>Cd(II)>Zn(II)>Mn(II), but differing in the adsorption capacities. In the studied conditions, the adsorption capacity of tannic acid immobilised activated carbon followed the order of Cu(2.23)>Fe(1.77)>Cd(1.51)>Zn(1.23)>Mn(1.13) in single systems and Fe(1.56)>Cd(1.48)>Zn(1.19)>Mn(1.11) in Cu(II) coupled competitive systems. The adsorption data was correlated to Langmuir and Freundlich isotherm for each metal ion and the data fitted better to the Langmuir isotherm model. A combined ion exchange, complex formation and surface adsorption processes were believed the major adsorption mechanisms playing role in the binding of metal ions. Adsorbed metal ions were effectively desorbed (90.2–98.4%) by using 0.1M HCl without destroying the modified adsorbent.
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Lead Particles in Potable Water
Article
  • Jun 2007
The presence of lead particles in tap water is an under-appreciated cause of lead poisoning in the United States. Routine water sampling procedures can "miss" lead particles present in drinking water. Consequently, the true extent of human exposure through this type of lead contamination can be underestimated. The authors describe recent cases of lead poisoning in Washington, D.C., Greenville, N.C., and Durham, N.C., when approved water sampling procedures did not show cause for alarm. Also, the authors compare the bioavailability of lead particles when ingested to their detection in drinking water samples and, in turn, compare human exposure to what utilities detect in water samples. Their findings reveal the potential limitations in current lead detection methods. This information can be used to improve current water sampling and preservation procedures.
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The Removal of Manganese, Iron and Ammonium Nitrogen on Impregnated Activated Carbon
Article
  • Feb 2007
  • DESALINATION
Intensive development of industry branches and agriculture causes a progressive deterioration of natural environment and a decrease in drinking water resources. Both in surface waters and underground waters, the increase in concentration of different elements and compounds which are dangerous for humans is observed. Unfortunately, the removal of these impurities by means of traditional methods is not always effective. Therefore, new, more and more efficient and modern methods of water treatment are searched for. In natural conditions, iron and manganese mostly occur in the form of hydrocarbons, sulphates, chlorides, combinations with humus compounds and sometimes in the form of phosphates. While getting into contact with air, these elements precipitate from water in the form of dark deposits, and water becomes turbid and dark-brown. The occurrence of these elements always creates some problems during water treatment. The occurrence of iron and manganese causes that water-pipe network to become overgrown. At much higher concentrations, both iron and manganese also have disadvantageous influence on people and animals. What is more, over-concentration of ammonium nitrogen accelerates the corrosion of water conduits and it complicates the processes of chlorination creating chloramines. Underground waters are often not suitable for direct municipal and industrial utilization. That is why they ought to be treated in a proper way. There are many methods of their treatment, which allow removing manganese, iron and ammonium nitrogen from water; however, they do not fulfil the sharpened norms of water quality. What is more, they make some troubles in technological systems. In the research, a trial of usage the impregnated, activated carbon, which has the symbol WD extra, was conducted. The porous structure of technical and impregnated activated carbon was analysed.
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