CWEA – Sanitaire Aeration Systems PDF
Preview CWEA – Sanitaire Aeration Systems
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 2 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. 3 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 6 SAEs of Various Aeration Technologies (standard conditions) • Fine Bubble (full floor coverage) 6.6 – 10.8 lbs.O /BHP-hr 2 • 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. 7 7 MECHANICAL AERATION SAE = 2 to 3 lbs O /BHP-hr • 2 High Maintenance Requirements • gearboxes - splashing - aerosols - icing - 8 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 • 10
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