CWEA – Sanitaire Aeration Systems

42 Pages·2014·11.31 MB·English

Aeration Systems and
Efficient Oxygen Transfer
Overview
• Introduction
• Aeration System Selection and
Options
• Fine Bubble Aeration System
Advantages
• SANITAIRE® Fine Bubble
Aeration Systems
• OSCAR® Aeration Control
Systems
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What makes the aeration system so
important?
•The Aeration System represents 1-2% of the cost of a new treatment
plant, but -
•Energy required for aeration in a municipal wastewater treatment plant
typically comprises 50-75% of a plant’s total energy expenditure.
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AERATION SYSTEM SELECTION
• Selection criteria
- Energy efficiency
- Long term reliability
- Low maintenance requirements
- Capital cost
- Ease of installation
4
Standard Aeration Efficiency
• SAE – Term typically applied to mechanical aerators
• Can be applied to diffused aeration systems – includes both air
and pressure
• Mass of oxygen delivered per unit of energy
• Units: Lbs of oxygen per BHP-hr or per kW-hr
5
Types of Aeration Systems
Jet Aeration
Mechanical and
Mechanical/FB
Hybrid Aeration
Coarse Bubble Fine Bubble
Diffused Aeration Diffused Aeration
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SAEs of Various Aeration Technologies
(standard conditions)
• Fine Bubble (full floor coverage) 6.6 – 10.8 lbs.O /BHP-hr
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• Fine Bubble (spiral roll) 3.3 – 6.6 lbs.O /BHP-hr
2
• Jet Aeration 3.6 – 5.7 lbs.O /BHP-hr
2
• Mechanical Aerators 1.8 – 3.4 lbs.O /BHP-hr
2
• Coarse Bubble 2.1 – 3.1 lbs.O /BHP-hr
2
• Aspirating Aerators 0.8 – 1.3 lbs.O /BHP-hr
2
Data from ASCE WEF Manual of Practice 8: Design of Municipal
Wastewater Treatment Plants.
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MECHANICAL AERATION
SAE = 2 to 3 lbs O /BHP-hr
•
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High Maintenance Requirements
•
gearboxes
-
splashing
-
aerosols
-
icing
-
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JET AERATION EFFICIENCY & EQUIPMENT
SOTE similar to fine bubble aeration
•
Requires blowers, pumps, & valve gallery
•
Total SAE similar to coarse bubble
•
3 - 4 lbs. oxygen/BHP/hr
•
Limited turn-up / turn-down
•
‘plumber’s nightmare’
9
COARSE BUBBLE EFFICIENCY/MAINTENANCE
Side or mid-width roll
•
Roughly 0.75% SOTE per foot submergence
•
3 - 4 lbs oxygen/BHP/hr
•
Typically requires 50 - 60% more power than fine bubble fixed floor
•
Near zero maintenance
•
Tank can be left dry and exposed for extended period
•
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