Steven J. Skerlos

A New Planning and Design Paradigm to Achieve Sustainable Resource Recovery from Wastewater

To employ technologies that sustainably harvest resources from wastewater (for example struvite granules shown here), new perceptions and infrastructure planning and design processes are required.

Perspectives on anaerobic membrane bioreactor treatment of domestic wastewater: A critical review

Interest in increasing the sustainability of water management is leading to a reevaluation of domestic wastewater (DWW) treatment practices. A central goal is to reduce energy demands and environmental impacts while recovering resources. Anaerobic membrane bioreactors (AnMBRs) have the ability to produce a similar quality effluent to aerobic treatment, while generating useful energy and producing substantially less residuals. This review focuses on operational considerations that require further research to allow implementation of AnMBR DWW treatment. Specific topics include membrane fouling, the lower limits of hydraulic retention time and temperature allowing for adequate treatment, complications with methane recovery, and nutrient removal options. Based on the current literature, future research efforts should focus on increasing the likelihood of net energy recovery through advancements in fouling control and development of efficient methods for dissolved methane recovery. Furthermore, assessing the sustainability of AnMBR treatment requires establishment of a quantitative environmental and economic evaluation framework.

A Review of Engineering Research in Sustainable Manufacturing

Karl R. Haapala 1 School of Mechanical, Industrial, and Manufacturing Engineering, Oregon State University, 204 Rogers Hall, Corvallis, OR 97331 e-mail: Karl.Haapala@oregonstate.edu Fu Zhao School of Mechanical Engineering, Division of Environmental and Ecological Engineering, Purdue University, 585 Purdue Mall, West Lafayette, IN 47907 e-mail: fzhao@purdue.edu Jaime Camelio Department of Industrial and Systems Engineering, Virginia Polytechnic Institute and State University, 235 Durham Hall, Blacksburg, VA 24061 e-mail: jcamelio@vt.edu John W. Sutherland Division of Environmental and Ecological Engineering, Purdue University, 322 Potter Engineering Center, West Lafayette, IN 47907 e-mail: jwsuther@purdue.edu Steven J. Skerlos Department of Mechanical Engineering, University of Michigan, 2250 GG Brown Building, Ann Arbor, MI 48105 e-mail: skerlos@umich.edu David A. Dornfeld Department of Mechanical Engineering, University of California, 6143 Etcheverry Hall, Berkeley, CA 94720 e-mail: dornfeld@berkeley.edu I. S. Jawahir Department of Mechanical Engineering, University of Kentucky, 414C UK Center for Manufacturing, Lexington, KY 40506 e-mail: jawahir@engr.uky.edu A Review of Engineering Research in Sustainable Manufacturing Sustainable manufacturing requires simultaneous consideration of economic, environmen- tal, and social implications associated with the production and delivery of goods. Funda- mentally, sustainable manufacturing relies on descriptive metrics, advanced decision- making, and public policy for implementation, evaluation, and feedback. In this paper, recent research into concepts, methods, and tools for sustainable manufacturing is explored. At the manufacturing process level, engineering research has addressed issues related to planning, development, analysis, and improvement of processes. At a manufac- turing systems level, engineering research has addressed challenges relating to facility operation, production planning and scheduling, and supply chain design. Though economi- cally vital, manufacturing processes and systems have retained the negative image of being inefficient, polluting, and dangerous. Industrial and academic researchers are re- imagining manufacturing as a source of innovation to meet society’s future needs by under- taking strategic activities focused on sustainable processes and systems. Despite recent developments in decision making and process- and systems-level research, many chal- lenges and opportunities remain. Several of these challenges relevant to manufacturing process and system research, development, implementation, and education are highlighted. [DOI: 10.1115/1.4024040] Andres F. Clarens Department of Civil and Environmental Engineering, University of Virginia, D220 Thornton Hall, Charlottesville, VA 22904 e-mail: aclarens@virginia.edu Jeremy L. Rickli Department of Industrial and Systems Engineering, Virginia Polytechnic Institute and State University, 217 Durham Hall, Blacksburg, VA 24061 e-mail: jlrickli@vt.edu Corresponding author. Contributed by the Manufacturing Engineering Division of ASME for publication in the J OURNAL OF M ANUFACTURING S CIENCE AND E NGINEERING . Manuscript received July 11, 2012; final manuscript received March 4, 2013; published online July 17, 2013. Editor: Y. Lawrence Yao. Manufacturing and Sustainability The concept of sustainability emerged from a series of meetings and reports in the 1970s and 1980s, and was largely motivated by environmental incidents and disasters as well as fears about Journal of Manufacturing Science and Engineering C 2013 by ASME Copyright V AUGUST 2013, Vol. 135 / 041013-1 Downloaded From: http://manufacturingscience.asmedigitalcollection.asme.org/ on 07/09/2014 Terms of Use: http://asme.org/terms

Psychrophilic anaerobic membrane bioreactor treatment of domestic wastewater.

A bench-scale anaerobic membrane bioreactor (AnMBR) equipped with submerged flat-sheet microfiltration membranes was operated at psychrophilic temperature (15 °C) treating simulated and actual domestic wastewater (DWW). Chemical oxygen demand (COD) removal during simulated DWW operation averaged 92 ± 5% corresponding to an average permeate COD of 36 ± 21 mg/L. Dissolved methane in the permeate stream represented a substantial fraction (40-50%) of the total methane generated by the system due to methane solubility at psychrophilic temperatures and oversaturation relative to Henrys law. During actual DWW operation, COD removal averaged 69 ± 10%. The permeate COD and 5-day biochemical oxygen demand (BOD(5)) averaged 76 ± 10 mg/L and 24 ± 3 mg/L, respectively, indicating compliance with the U.S. EPAs standard for secondary effluent (30 mg/L BOD(5)). Membrane fouling was managed using biogas sparging and permeate backflushing and a flux greater than 7 LMH was maintained for 30 days. Comparative fouling experiments suggested that the combination of the two fouling control measures was more effective than either fouling prevention method alone. A UniFrac based comparison of bacterial and archaeal microbial communities in the AnMBR and three different inocula using pyrosequencing targeting 16S rRNA genes suggested that mesophilic inocula are suitable for seeding psychrophilic AnMBRs treating low strength wastewater. Overall, the research described relatively stable COD removal, acceptable flux, and the ability to seed a psychrophilic AnMBR with mesophilic inocula, indicating future potential for the technology in practice, particularly in cold and temperate climates where DWW temperatures are low during part of the year.

Use of Air-Liquid Two-Phase Flow in Hydrophobic Microfluidic Channels for Disposable Flow Cytometers

This paper describes a disposable flow cytometer that uses an air-liquid two-phase microfluidic system to produce a focused high-speed liquid sample stream of particles and cells. The susceptibility of thin liquid columns to instabilities may suggest that focusing of sample liquids with streams of air would be difficult. The design of channel geometry, control of flow rates, and use of appropriate surface chemistries on the channel walls, however, enabled the generation of thin (15–100 μm) and partially bounded sample streams that were stable and suitable for rapid cell analysis. Using an inverted epi-fluorescence microscope with a photo-multiplier tube, we demonstrated that the system is capable of counting the number of beads and C2C12 myoblast cells. The effects of different flow rates and surface chemistries of the channel walls on the air-liquid two-phase flows were characterized using optical and confocal microscopy. Use of air instead of liquids as a sheath fluid eliminates the need for large sheath liquid reservoirs, and reduces the volume and weight requirements. The low manufacturing cost and high volumetric efficiency make the air-sheath flow cytometer attractive for use as a stand-alone device or as an integrated component of bio-artificial hybrid microsystems.

A study of fuel efficiency and emission policy impact on optimal vehicle design decisions

Recent environmental legislation, such as the European Union Directive on End-of-Life Vehicles and the Japanese Home Electric Appliances Recycling law, has had a major influence on product design from both an engineering and an economic perspective. This article presents a methodology for studying the effects of automobile fuel efficiency and emission policies on the long-term design decisions of profit-seeking automobile producers competing in an oligopoly market. Mathematical models of engineering performance, consumer demand, and manufacturing costs are developed for a specific market segment, and game theory is utilized to simulate competition among firms to predict design choices of producers at market equilibrium. Several policy scenarios are evaluated for the small car market, including corporate average fuel economy (CAFE) standards, carbon dioxide (CO 2 ) emissions taxes, and diesel technology quotas. The results indicate that leveraging CO 2 taxes on producers for expected life cycle emissions yields diminishing returns on fuel efficiency improvement per regulatory dollar as the taxes increase, while CAFE standards achieve higher average fuel efficiency per regulatory dollar. Results also indicate that increasing penalties for violation of CAFE standards can result in lower cost to producers and consumers because of the effects of competition, and penalties based on fuel economy or emissions alone may not be sufficient incentive for producers to bring more costly alternative fuel vehicles into the market. The ability to compare regulations and achieve realistic trends suggests that including engineering design and performance considerations in policy analysis can yield useful predictive insight into the impact of government regulations on industry, consumers, and the environment.

Navigating Wastewater Energy Recovery Strategies: A Life Cycle Comparison of Anaerobic Membrane Bioreactor and Conventional Treatment Systems with Anaerobic Digestion

The objective of this study was to evaluate emerging anaerobic membrane bioreactor (AnMBR) technology in comparison with conventional wastewater energy recovery technologies. Wastewater treatment process modeling and systems analyses were combined to evaluate the conditions under which AnMBR may produce more net energy and have lower life cycle environmental emissions than high rate activated sludge with anaerobic digestion (HRAS+AD), conventional activated sludge with anaerobic digestion (CAS+AD), and an aerobic membrane bioreactor with anaerobic digestion (AeMBR+AD). For medium strength domestic wastewater treatment under baseline assumptions at 15 °C, AnMBR recovered 49% more energy as biogas than HRAS+AD, the most energy positive conventional technology considered, but had significantly higher energy demands and environmental emissions. Global warming impacts associated with AnMBR were largely due to emissions of effluent dissolved methane. For high strength domestic wastewater treatment, AnMBR recovered 15% more net energy than HRAS+AD, and the environmental emissions gap between the two systems was reduced. Future developments of AnMBR technology in low energy fouling control, increased flux, and management of effluent methane emissions would make AnMBR competitive with HRAS+AD. Rapid advancements in AnMBR technology must continue to achieve its full economic and environmental potential as an energy recovery strategy for domestic wastewater.

Greenhouse Gas Emissions Payback for Lightweighted Vehicles Using Aluminum and High-Strength Steel

Summary In this article we consider interactions between life cycle emissions and materials flows associated with lightweighting (LW) automobiles. Both aluminum and high-strength steel (HSS) lightweighting are considered, with LW ranging from 6% to 23% on the basis of literature references and input from industry experts. We compare the increase in greenhouse gas (GHG) emissions associated with producing lightweight vehicles with the saved emissions during vehicle use. This yields a calculation of how many years of vehicle use are required to offset the added GHG emissions from the production stage. Payback periods for HSS are shorter than for aluminum. Nevertheless, achieving significant LW with HSS comparable to aluminum-intensive vehicles requires not only material substitution but also the achievement of secondary LW by downsizing of other vehicle components in addition to the vehicle structure. GHG savings for aluminum LW varies strongly with location where the aluminum is produced and whether secondary aluminum can be utilized instead of primary. HSS is less sensitive to these parameters. In principle, payback times for vehicles lightweighted with aluminum can be shortened by closed-loop recycling of wrought aluminum (i.e., use of secondary wrought aluminum). Over a 15-year time horizon, however, it is unlikely that this could significantly reduce emissions from the automotive industry, given the challenges involved with enabling a closed-loop aluminum infrastructure without downcycling automotive body structures.

Current advances in sustainable Metalworking Fluids research

Metalworking Fluids (MWFs) have a history of harming the environment and the health of workers, resulting in pressures to re-design them in accordance with sustainable manufacturing principles. In this paper, we review research being performed at the University of Michigan to minimise the life cycle environmental and health impacts of MWFs while simultaneously improving manufacturing performance. We highlight research contributions in the following areas: • formulation design • biological sensors • advanced recycling • the use of supercritical fluids. We conclude that it is possible to design more sustainable metalworking fluid systems either by extending dramatically the in-use lifetime of water-based MWFs or better yet by switching to gas-based Minimum Quantity Lubrication (MQL) systems.

Economic Assessment of Greenhouse Gas Emissions Reduction by Vehicle Lightweighting Using Aluminum and High-Strength Steel

The life cycle greenhouse gas (GHG) reduction benefits of vehicle lightweighting (LW) were evaluated in a companion article. This article provides an economic assessment of vehicle LW with aluminum and high-strength steel. Relevant cost information taken from the literature is synthesized, compiled, and formed into estimates of GHG reduction costs through LW. GHG emissions associated with vehicle LW scenarios between 6% and 23% are analyzed alongside vehicle life cycle costs to achieve these LW levels. We use this information to estimate the cost to remove GHG emissions per metric ton by LW, and we further calculate the difference between added manufacturing cost and fuel cost savings from LW. The results show greater GHG savings derived from greater LW and added manufacturing costs as expected. The associated production costs are, however, disproportionately higher than the fuel cost savings associated with higher LW options. A sensitivity analysis of different vehicle classes confirms that vehicle LW is more cost-effective for larger vehicles. Also, the cost of GHG emissions reductions through lightweighting is compared with alternative GHG emissions reduction technologies for passenger vehicles, such as diesel, hybrid, and plug-in hybrid electric powertrains. The results find intensive LW to be a competitive and complementary approach relative to the technological alternatives within the automotive industry but more costly than GHG mitigation strategies available to other industries.