Modelling the link amongst fine-pore diffuser fouling, oxygen transfer efficiency, and aeration energy intensity

Manel Garrido-Baserba; Reza Sobhani; Pitiporn Asvapathanagul; Graham W McCarthy; Betty H Olson; Victory Odize; Ahmed Al-Omari; Sudhir Murthy; Andrea Nifong; Johnnie Godwin; Charles B Bott; Michael K Stenstrom; Andrew R Shaw; Diego Rosso

doi:10.1016/j.watres.2016.12.027

Modelling the link amongst fine-pore diffuser fouling, oxygen transfer efficiency, and aeration energy intensity

Water Res. 2017 Mar 15:111:127-139. doi: 10.1016/j.watres.2016.12.027. Epub 2016 Dec 19.

Authors

Affiliations

¹ Department of Civil & Environmental Engineering, University of California, Irvine, CA 92697-2175, USA; Water-Energy Nexus Center, University of California, Irvine, CA 92697-2175, USA. Electronic address: manelg@uci.edu.
² Orange County Sanitation District, 10844 Ellis Ave, Fountain Valley, CA 92708, USA.
³ Department of Civil & Environmental Engineering, University of California, Irvine, CA 92697-2175, USA; Department of Civil Engineering and Construction Engineering Management, California State University, Long Beach, CA 90840, USA.
⁴ Santa Margarita Water District, 26111 Antonio Pkwy, Ladera Ranch, CA 92688, USA.
⁵ Department of Civil & Environmental Engineering, University of California, Irvine, CA 92697-2175, USA; Water-Energy Nexus Center, University of California, Irvine, CA 92697-2175, USA.
⁶ DC Water, 5000 Overlook Ave SW, Washington, DC 20032, USA.
⁷ World Water Works, 4000 SW 113th Street, Oklahoma City, OK 73173, USA.
⁸ Hampton Roads Sanitation District, Virginia Beach, VA 23471-0911, USA.
⁹ Department of Civil and Environmental Engineering, University of California, Los Angeles, CA 90095-1593, USA.
¹⁰ Black & Veatch, 8400 Ward Pkwy, Kansas City, MO 64114, USA.
¹¹ Department of Civil & Environmental Engineering, University of California, Irvine, CA 92697-2175, USA; Water-Energy Nexus Center, University of California, Irvine, CA 92697-2175, USA. Electronic address: bidui@uci.edu.

PMID: 28064087
DOI: 10.1016/j.watres.2016.12.027

Abstract

This research systematically studied the behavior of aeration diffuser efficiency over time, and its relation to the energy usage per diffuser. Twelve diffusers were selected for a one year fouling study. Comprehensive aeration efficiency projections were carried out in two WRRFs with different influent rates, and the influence of operating conditions on aeration diffusers' performance was demonstrated. This study showed that the initial energy use, during the first year of operation, of those aeration diffusers located in high rate systems (with solids retention time - SRT-less than 2 days) increased more than 20% in comparison to the conventional systems (2 > SRT). Diffusers operating for three years in conventional systems presented the same fouling characteristics as those deployed in high rate processes for less than 15 months. A new procedure was developed to accurately project energy consumption on aeration diffusers; including the impacts of operation conditions, such SRT and organic loading rate, on specific aeration diffusers materials (i.e. silicone, polyurethane, EPDM, ceramic). Furthermore, it considers the microbial colonization dynamics, which successfully correlated with the increase of energy consumption (r²:0.82 ± 7). The presented energy model projected the energy costs and the potential savings for the diffusers after three years in operation in different operating conditions. Whereas the most efficient diffusers provided potential costs spanning from 4900 USD/Month for a small plant (20 MGD, or 74,500 m³/d) up to 24,500 USD/Month for a large plant (100 MGD, or 375,000 m³/d), other diffusers presenting less efficiency provided spans from 18,000USD/Month for a small plant to 90,000 USD/Month for large plants. The aim of this methodology is to help utilities gain more insight into process mechanisms and design better energy efficiency strategies at existing facilities to reduce energy consumption.

Keywords: Activated sludge process; Aeration efficiency; Energy projection; Fine pore diffuser; Fouling.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't

MeSH terms

Bioreactors
Ceramics
Diffusion*
Oxygen*
Waste Disposal, Fluid

Substances

Oxygen