Papers by Michael Stenstrom
This report was printed on recycled paper. www.usc.edu/dept/geography/ESPE The Center for Sustain... more This report was printed on recycled paper. www.usc.edu/dept/geography/ESPE The Center for Sustainable Cities engages in multidisciplinary research and education on the environmental, social and economic sustainability challenges facing metropolitan regions, and contributes to the development of public policy that improves the natural and human environment of cities.
Proceedings of the Water Environment Federation, 2007
Abstract: The lack of proper wastewater treatment results in production of CO 2 and CH 4 without ... more Abstract: The lack of proper wastewater treatment results in production of CO 2 and CH 4 without the opportunity for carbon sequestration and energy recovery, with deleterious effects for global warming. Without extending wastewater treatment to all urban areas ...
Proceedings of the Water Environment Federation, 2017
World Environmental and Water Resources Congress 2020, 2020
A process-water, oxygen transfer compliance test was performed in November, 1983 on a 6.0-m 3/S (... more A process-water, oxygen transfer compliance test was performed in November, 1983 on a 6.0-m 3/S (138-mgd) high purity oxygen activated sludge plant. The plant failed this and a subsequent process water test and the failure required the development of a procedure to determine oxygen transfer capacity of the plant. The American Society of Civil Engineer's clean water oxygen transfer standard was used in conjunction with process modeling and pilot-scale alpha factor testing. Clean water test results and a dynamic process model which predicts head-space gas purity are presented.
Davis of the UCLA Water Quality Laboratory helped with pilot plant construction and data collecti... more Davis of the UCLA Water Quality Laboratory helped with pilot plant construction and data collection during parts of the study .
Environmental Pollution, 2020
Breaking of biochar during compaction of amended soil used in roadside biofilters or landfill cov... more Breaking of biochar during compaction of amended soil used in roadside biofilters or landfill cover can affect infiltration, clog amended soil, and change its pollutant removal capacity. It is unknown how the initial biochar size affects the biochar breaking, clogging potential, and contaminant removal capacity of biochar-amended soil. We compacted a mixture of coarse sand and biochar with sizes smaller than, similar to or larger than the sand and applied stormwater contaminated with E. coli in columns packed with the compacted sand-biochar mixture. Coating biochar with a dye and analyzing the dye concentration in the broken biochar particles eluted from the columns, we proved that biochar predominantly breaks under compaction by disintegration or splitting, not abrasion, and increases in biochar size decrease the likelihood of biochar breaking. We attribute this result to the effective dissipation of compaction energy through a greater number of contact points between a large biochar particle and the adjacent particles. Most of the broken biochar particles deposited in the pores, resulting in an exponential decrease in hydraulic conductivity of amended sand with an increase in suspended sediment loading. The clogging rate was higher in the columns with smaller biochar. The columns with small biochar also exhibited high E. coli removal capacity, partly because of an increase in straining by the smaller pore size created by the deposition of fine biochar particles created during compaction. These results are useful in selecting appropriate biochar size for its application in soils and roadside biofilters for water treatment.
Proceedings of the Water Environment Federation, 2013
Wastewater aeration is a highly complex and dynamic process for which site-specific analysis and ... more Wastewater aeration is a highly complex and dynamic process for which site-specific analysis and control are needed. Off-gas testing is a method that can determine the aeration process requirements and conditions in real-time, so that appropriate operational changes and control strategies can be implemented. For this research project, off-gas analyzers were installed at five wastewater treatment plants in Southern California to continuously measure standard oxygen transfer efficiency (SOTE) and off-gas flux and perform a subsequent energy analysis. The results were as expected and show that there is an inverse relationship between SOTE and offgas flux that follows a distinct diurnal pattern. The energy analysis showed that the energy usage during peak demand is amplified due to compounding factors of increased COD and volumetric wastewater load. Utilizing off-gas monitoring to determine process requirements and performance, many energy saving strategies (e.g. blower type, variable frequency drives, control strategies) that can lower peak and overall energy demand are feasible and can be implemented in a energy rebate program.
Applied Biochemistry and Biotechnology, 1995
... CJ RIVARD, *'1 J. B . RODRIGUEZ, 2 NJ NAGLE, 1 JR SELF, 2 BD KAY, 1 PN SOLTANPOUR, 2 AND... more ... CJ RIVARD, *'1 J. B . RODRIGUEZ, 2 NJ NAGLE, 1 JR SELF, 2 BD KAY, 1 PN SOLTANPOUR, 2 AND RA NIEVES ~ ... The authors thank Bert Yungen and Ian Boatwood of Pan Pacific Fisheries, Inc., for facilitating the procurement of tuna-processing wastes (sludge). ...
Water Environment Research, Sep 1, 2004
Journal of Water Pollution Control Federation, 1989
A process-water, oxygen transfer compliance test was performed in November, 1983 on a 6.0-m 3/S (... more A process-water, oxygen transfer compliance test was performed in November, 1983 on a 6.0-m 3/S (138-mgd) high purity oxygen activated sludge plant. The plant failed this and a subsequent process water test and the failure required the development of a procedure to determine oxygen transfer capacity of the plant. The American Society of Civil Engineer's clean water oxygen transfer standard was used in conjunction with process modeling and pilot-scale alpha factor testing. Clean water test results and a dynamic process model which predicts head-space gas purity are presented.
Water Environment Research, Sep 1, 2011
IWA Publishing eBooks, May 15, 2023
Chapter 9 Aeration and Mixing in the textbook Biological Wastewater Treatment: Principles, Modell... more Chapter 9 Aeration and Mixing in the textbook Biological Wastewater Treatment: Principles, Modelling and Design (Chen et al., 2020) introduces the fundamental quantities related to oxygen transfer and aeration, their dynamics in relation to the biological process dynamics, the equipment required to provide aeration, and the relation between mixing and aeration. Here we also present the energy implications of aeration and mixing. This chapter applies all of this content through examples, questions and exercises. 9.2 LEARNING OBJECTIVES After the successful completion of this chapter, the reader will be able to: • Describe the equipment for aeration and mixing and its functioning. • Size the equipment based on average and peak process conditions. • Specify the number of aeration diffusers necessary to meet the oxygen requirement of a biological process. • Quantify the mixing effectiveness in a suspended-growth process. 9.3 EXAMPLES Example 9.3.1 Aeration system design A wastewater treatment plant requires an average mass of oxygen per day RO2 = 8,640 kgO2/d. The aeration tanks are 5 m deep and the diffusers are to be installed 30 cm above the floor. The diffusers utilize 9 inch
IWA Publishing eBooks, 2018
Journal of Cleaner Production, Feb 1, 2022
Tratamiento biológico de aguas residuales: principios, modelación y diseño, 2018, ISBN 9781780409245, págs. 273-305, 2018
Water Research, 2020
The entire vascular tree of 58 lower extremities with high-grade critical limb ischemia (CLI) was... more The entire vascular tree of 58 lower extremities with high-grade critical limb ischemia (CLI) was assessed with three-station time resolved imaging of contrast kinetics (TRICKS) magnetic resonance angiography (T-MRA) and correlated with digital subtraction angiography (DSA) examinations and TransAtlantic Inter-Society Consensus II (TASC II) guidelines. Kappa (κ) statistics were utilized to evaluate the agreement of stenosis scores (5-point scale; 0 normal to 4 occlusion) based on T-MRA and DSA. With DSA as the standard, significant stenosis instances (stenosis score ≥2) among vascular segments were compared. The κ-statistics of image quality (4-point scale; 1 nondiagnostic to 4 excellent) of T-MRA and TASC II classification assessed by a radiologist and a vascular surgeon were also evaluated. Among 870 vascular segments, excellent agreement was observed between T-MRA and DSA (mean κ = 0.883) in revealing stenosis (mean stenosis score, 2.1 ± 1.3 versus 2.0 ± 1.3). T-MRA harbored overall high sensitivity (99.5%), specificity (93.6%), positive predictive value (95.4%), negative predictive value (99.6%), and accuracy (97.7%) in depicting significant stenosis. Excellent interobserver agreement (mean κ = 0.818) of superb image quality (mean score = 3.5-3.6) of T-MRA and outstanding agreement of TASC II classification of aortoiliac and femoral-popliteal lesions (κ = 0.912-0.917) between two raters further verified the clinical feasibility of T-MRA for treatment planning. * * Surgical findings was regarded as gold standard while there were discordance between T-MRA and DSA (4 DP and 2PL were not opacified on DSA but seemed patent on MRA with subsequent surgical confirmation of patency). * Stenosis scores (T-MRA versus DSA) were assessed with kappa statistics.
Proceedings of the Water Environment Federation, 2015
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Papers by Michael Stenstrom