Volume 2-05, Chapter 3 - City of Wichita

Section 3.3.3 - Alum Treatment
3.3.3
Alum Treatme
nt
Secondary Water Quality Facility
Description: Chemical treatmentt of stormwater runoff
entering a wet pond by injecting liquid alum into storm
sewer lines on a flow-weighted
basis during rain
events.
ADVANTAGES / BENEFITS:
• Reduces concentrations of total suspended sediments,
phosphorus, and heavy metals
DISADVANTAGES / LIMITATIONS:
• Dependent on pH level ranging from 6.0 to 7.5 during
treatment process
• Intended
for areas requiring
large-scale
stormwater
treatment from a piped stormwater drainage system
• High maintenance requirements
• Alum application will lower pH of receiving
waters
• High capital and
operations and maintenance costs
MAINTENANCE
REQUIREMENTS:
• Adjust dosage to ensure proper dosage
and delivery
of
runoff to the settling pond
H
H/ M
H
H
KEY CONSIDERATIONS
• Dredge
settling pond and properly
dispose of
accumulated floc
POTENTIAL* POLLUTANT REMOVAL
Total Suspended Solids
Nutrients – Total Phosphorus & Total Nitrogen
Metals
– Cadmium, Copper, Lead & Zinc
Pathogens – Coliform, Streptococci & E. Coli
STORMWATER MANAGEMENT
SUITABILITY
Water Quality Protection
Channel Protection
On-Site Flood Control
Downstream
Flood Control
Accepts Hotspo
Runoff: Yes, For Lined
Off-line Ponds
IMPLEMENTATION CONSIDERATIONS
L Land Requirements
H Relative Capital Costs
H Maintenance Burden
Residential Subdivision Use: Yes
High
Density/Ultra-Urban: Yes
Drainage Area: 25 acres min.
Soils: No restrictions
Other Considerations:
• Regional Treatment
L=Low M= =Moderate H=High
*Depends On Specific Installation
Volume 2, Technical Guidance
Page 3 - 157