Transcript The use of calcite contactors for Iron and Manganese removal 1 Tim Bradley

The use of calcite contactors for Iron and
Manganese removal
Tim Bradley
Dr. Martine Poffet
Jochen Kallenberg
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25.05.2016
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Overview
Background on Fe and Mn Removal - Chemistry
Methods for removal
Calcite Contactors for Fe and Mn removal
Water Quality specifics
Omya’s Calcium Carbonate Products
Questions
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Drinking water treatment
– For protecting the customer’s health:
to guarantee the water quality and stability
to avoid the dissolution of heavy metals from the water works
to avoid red colored water from the tap
– For maintaining the water works:
against corrosion
against scaling
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used and disclosed without Omya explicit written authorization.
Neutralization / Remineralization
– Neutralization:
to increase the water pH
(→ neutralization of free CO2)
– Remineralization:
to increase the water hardness
(→ increase calcium content)
– Stabilization:
to obtain a stabilized water quality
(→ to reach the calco-carbonic equilibrium)
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Iron
Iron is the fourth most abundant element in earth’s crust.
The ferrous oxides and sulfides are the usual source of dissolved Iron in waters.
The weathering of iron silicates also produce dissolved iron in surface water.
Common deposits
ferric oxides, hematite,
FeO3
ferric hydroxide
Fe(OH)3 source of red and yellow color
Sedimentary forms of iron may include sulfides:
pyrite and marcasite
FeS2
Carbonates
FeCO3
mixed oxides, magnetite
Fe3O4
This document contains proprietary information which shall not be
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Iron
Iron is very soluble in a reducing environment or in natural waters such:
low oxygen containing ground water,
low oxygen surface waters,
deep waters of eutrophic lakes, larger rivers and reservoirs.
Depending on water quality, iron can exist in three physical forms,
As soluble reduced form
Small oxidized colloidal particles
Large Oxidized particles
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Iron
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Iron
Limits
EPA Secondary Drinking Water Regulations 1991
Limit iron to 0.3 mg/L for taste and aesthetic reasons.
Disadvantages
Metallic taste - threshold reported at 0.1 to 0.2 mg/L
Ferrous iron can stain laundry, household fixtures, glasses, dishes.
Iron discolors industrial products such as Textiles and Paper.
Iron precipitates can clog pipes and support growth of iron bacteria which can
cause taste and odor problems.
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Manganese
Manganese is and the eleventh most abundant element in earth’s crust.
Manganese is similar to Iron in that it is usually found in the Mn+2 oxidation state in
anoxic ground waters.
Oxidation of Mn2+ can lead to three different oxides of manganese depending on
pH MnO2, Mn2O3,and Mn3O4, with the predominant form being MnO2.
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Manganese
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Manganese
Disadvantages
Impairs the taste of drinking water and heated beverages such as coffee and tea.
This was found at levels above 0.05 mg/L.
Staining of laundry, especially black spots
Staining of household fixtures, glasses, dishes.
Build up in pipes which slough off occasionally causing spotting.
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Manganese
Limits
In 1977 the USEPA issued a proposed rule for manganese control under the Safe
Drinking Water Act (SDWA) for a non-enforceable Secondary Maximum
Contaminant Level (SMCL) of 0.05 mg/L. This was done for aesthetic reasons not
health reasons.
In 2001 the limits were reviewed with a focus on potential health concerns. The
EPA concluded in 2004 that setting National Primary Drinking Water Regulations
was unwarranted due to lack or meaningful opportunity of health risk.
However, some states have enacted their own regulations.
New York has set a limit of 0.3 mg/L for Mn alone and a combined limit of 0.5mg/L
if both Fe and Mn are present.
The WHO established a health guideline of 0.4mg/L and aesthetic limit 0.05mg/L.
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Methods of Removal
1. Oxidation using oxygen (aeration), Chlorine, Chlorine dioxide, Potassium
permanganate or Ozone, all followed by sedimentation and filtration.
2. Manganese Greensand, again followed by sedimentation and filtration
3. Ion Exchange
4. Lime Softening
5. Sequestering Chemicals
6. Calcite Contactors.
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Omya products for water remineralization
Filtracarb ® / Puri-cal ®
– Calcite contactor (filtration bed)
Closed / Open system
Upstream / Downstream
– Long term international expertise
40 years technical feedback
Germany, France, Spain, USA, Qatar
 New products evaluation from Morocco,
Serbia, Greece, Australia, Jordan, UAE
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used and disclosed without Omya explicit written authorization.
Juraperle JW – Wasserstudie Omya
Fe and Mn Removal - Nethen Germany
Nethen Water Treatment Plant installed in 1994.
Omya has supplied material to treat aggressive waters in this region for 40 yrs.
One side effect of the treatment is the removal of Fe and Mn.
In Nethen the focus is on the removal of Fe
and Mn because of the high levels in the
incoming water.
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Process Overview
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used and disclosed without Omya explicit written authorization.
Process Overview - Degassification / Oxidation
Air is bubbled through the raw water to remove CO2 and odor causing gasses
The incoming air is sent through a dust filter and the exiting air treated with a
carbon filter to remove odors
Oxidation occurs at this step. Precipitating both Fe(OH)3(s) and MnO2(s)
Air Volume ~1,300 cubic feet per minute
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Process Overview – First Stage, Fe Removal
Four Coarse Calcite contactors in series
Calcite Granules measuring 1.8 – 2.5 mm, 12 inch gravel base in bottom of filter
pH rise from 5.7 to 7.1
Fe precipitates, is captured in filter and later back flushed
Flow ~ 970 gallons per minute
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Process Overview – Second Stage, Mn Removal
Four Fine Calcite contactors operated in series
Calcite Granules measuring 1.2 - 1.8 mm
pH rise from 7.1 to 7.7
Mn precipitates, is captured in filter and later back flushed
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Process Overview – Third Stage, Degassification
In this stage the final water is further degassed to reach final pH
It has been found that this stage is unnecessary. But has been left in place for
security.
Turbidity 0.07
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used and disclosed without Omya explicit written authorization.
Process Overview – Water Quality
Water quality
Parameters
pH
Iron
Manganese
Total hardness
Raw water
Unit
mg/L
mg/L
mg/L as CaCO3
Filter 1
Filter 2
Treated water
Expected value Expected value Expected value Expected value
5.7 ± 0.5
7.1 ± 0.4
7.7 ± 0.2
7.8 ± 0.1
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< 0.5
< 0.02
< 0.02
0.3 ± 0.2
< 0.02
< 0.02
90 ± 36
160 ± 18
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Contactor Specifics
Flow 1.4 MGPD, (970 gals/min)
Eight Calcite Contactors
(4) Fe, (4) Mn
Operate 2–4 filters based on
flow and contaminant demand
1st Stage (Fe) – Recharge 28 to
48 hours with 3 metric tons
2nd Stage (Mn) – Recharge 340
to 470 hours with 6 metric tons
Bed Height 72 – 90 inches
Back flush volume 38,000 gals
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Remineralization process
Example:
– Downstream closed system
– Contact time: 20 – 40 min
(A) Airing
(B) Refill
(C) Height over the filter
(D) Calcite bed (Filtracarb ®)
(E) Filtering media
(F) Filter support
(G) Air inlet
(H) Intlet = Raw water
Outlet = Backwash wastewater
(I) Inlet = Backwash
Outlet = Remineralized water
(J) Drain / Manhole
(K) Drain / Manhole
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Eau de
rinçage
Eau
reminéralisée
25.05.2016
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used and disclosed without Omya explicit written authorization.
Juraperle JW – Wasserstudie Omya
Materials

Gravel
Base for coarse

Coarse Calcite
1.8 – 2.5 mm

Fine Calcite
1.2 – 1.8 mm
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Calcite Material with impurities
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Puri-cal material for remineralization
Filtracarb / Puri-cal applications:
– CO2-removal and remineralization of soft water,
– remineralization of distillate and/or R.O.-water,
– removal of iron and manganese as well as aluminum.
Omya’s quality
– Very pure products
Omya Calcium Carbonate Products
 Insoluble part: 0.1 – 2% (Acid insol. content)
 Ca and Mg carbonate > 98%
- CaCO3: marble, calcite, chalk
- MgCO3 : 0.5 – 3.5%
 NSF 60 Certified EN 1018 norm
 Calcium Carbonate used for treatment of drinking
Filtracarb / Puri-cal for Remineralization
water
This document contains proprietary information which shall not be
used and disclosed without Omya explicit written authorization.
Calcium carbonate (CaCO3) – carbon dioxide (CO2) system
System H2O – CO2 – CaCO3
– CO2 in water:
CO2 + H2O ↔ H2CO3
– CaCO3 and CO2:
CaCO3 + H2CO3 ↔ Ca(HCO3)2
Product consumption: 2.3 - 2.5 g CaCO3 per g CO2
Hardness increase: 2.3 - 2.5 g CaCO3 par g CO2
L. Birnhack, et al., Desalination (2011)
Water
CaCO3
Physico-chemical properties
(temperature, conductivity,
hardness, free CO2,
alkalinity)
Geology
Chemistry
Granulometry
Infrastructure
Setting
Flow rate
Equipment
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used and disclosed without Omya explicit written authorization.
Calco-carbonic equilibrium
Managing Aggressiveness / Scaling:
Saturation pH is dependent on Water Hardness
Ideal LSI value is slightly positive +0.3 in order to be slightly scaling and non
leaching to piping.
Hardness > 50 Soft Water
< 150 Hard Water
Must adjust both pH and hardness
Calcium Carbonate Provides a cost effective means to accomplish this.
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used and disclosed without Omya explicit written authorization.
Thank you for your attention!
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25.05.2016
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used and disclosed without Omya explicit written authorization.
THE OMYA ADVANTAGE
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Experience Commitment
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