Civil Engineering Reference
In-Depth Information
Treatment Option
Advantages
Disadvantages
Sequestering
Operationally simple—only chemical feed and storage required
Does not remove iron and manganese—only holds them in
solution
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•
Inexpensive
•
Suitable for wellhead treatment
Effectiveness exhausted after 48 to 72 hr, which could lead to
staining problems for large storage volumes and long dead-end
pipelines
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Does not produce residuals that have to be handled
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Addition of phosphorus could enhance biological growth in
distribution system
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A free chlorine residual must be maintained in the system to
minimize regrowth
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Aeration and filtration
•
Can reduce high concentrations of iron
•
Generally considered to be unsuccessful for manganese removal at
neutral pH
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Simple to operate and maintain
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No chemicals to handle
•
Repumping usually required
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Not effective for removal of organically complexed iron
Chlorination and
filtration
Effective for Fe removal
Not effective on Mn without high pH and long detention time
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•
Operationally simple and stable
Not effective on organically complexed iron
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•
Able to provide primary disinfection benefits
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Readily accepted by regulatory agencies
•
KMnO
4
and filtration
•
Widely used and effective method for both Fe and Mn removal
•
Potential to overdose the KMnO
4
, which could cause pink water
complaints
•
Rapid reaction to oxidize both metals
•
Operationally simple
•
High chemical costs
•
Readily accepted by regulatory agencies
•
Not effective on organically complexed iron without a clarification
step
•
KMnO
4
is corrosive, so special handling is required
Ozonation and
filtration
Effective for both Fe and Mn removal
Potential to overoxidize Mn to permanganate, causing pink water
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Provides benefits in terms of taste and odor
High capital and energy costs
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Able to provide primary disinfection benefits
On-site generation required
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No chemicals to buy or store
Ozone equipment is complex and requires specialized servicing
•
•
TOC in the water could cause biological slime growth problems
in the system
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