You are here:
FINE PORE DIFFUSER FOULING: THE LOS ANGELES STUDIES
Citation:
Stenstrom, M. K. AND G. Masutani. FINE PORE DIFFUSER FOULING: THE LOS ANGELES STUDIES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-94/095 (NTIS 94-200839), 1994.
Impact/Purpose:
Information.
Description:
This report describes five fine pore diffuser evaluations conducted at three different wastewater treatment plants located in the greater Los Angeles area. The overall goal of the study was to evaluate the performance of fine pore diffusers using selected cleaning methods for extended periods of time at selected treatment plants. The major part of this study was conducted at the Whittier Narrows Water Reclamation Plant, which is operated by the Los Angeles County Sanitation Districts. This study evaluated fine pore ceramic disk and dome aeration systems using Hcl acid gas cleaning and a dome aeration systems without acid gas cleaning over a 25-month period. Second study, smaller in scope and effort, was conducted at the Valencia Water Reclamation Plant (also operated by the Districts). This study valuated fine pore plastic disk diffusers over a 13-month period. Third study, also smaller in scope and effort than he Whittier Narrows study, was conducted at the Terminal Island Wastewater Treatment Plant, operated by the City of Los Angeles. In this study, the performance of two membrane tube diffusers was evaluated over a 12-month period. This report summarizes the performance of six different aeration systems. The principal indicator of performance was oxygen transfer efficiency, as measured through off-gas analysis. For the Whittier Narrows study, changes in diffuser characteristics are also reported. The fine pore ceramic disk aeration system that was acid gas cleaned performed better than the ceramic dome systems that were acid gas cleaned as well as the control dome aeration system that received no cleaning. Part of the differences in performance between the disk system and the two dome system is attributable to mechanical problems with the domes. The cleaned and uncleaned dome systems had comparable transfer efficiencies during the study. Results for plastic disk system showed relatively consistent performance over the 13-month period. The tube systems showed high variability due to operational differences, and one tube system showed significant fouling over a relatively brief period. n important finding of this report is the variability of aeration system performance during day-to-day changes in plant input and operating modes. This report was submitted in partial fulfillment of Cooperative Agreement No. CR812167 by the American Society of Civil Engineers under subcontract to the University of California, Los Angeles under the partial sponsorship of the U.S. Environmental Protection Agency. The work reported herein was conducted over the period of 1986-1988. Project summary may be ordered as EPA/600/S-94/001).