Abstracts

Plenary, Talks, Posters

Ecological Engineering: Integrating Natural Processes With Conventional Technologies To Clean the Environment

B. C. "Bill" Wolverton, Ph.D.

Environmental Scientist

Wolverton Environmental Services, Inc.

Picayune, Mississippi, USA

The early 1970s was a period of feasting on the accolades of man's greatest technological achievement - the successful landing on the moon. After this momentous occasion, the National Aeronautics and Space Administration (NASA) began research to create a closed ecological life support system for long-term space habitation. As has often been the case in space research, much of their findings had practical applications here on earth. Few, however, could have envisioned a technologically advanced organization such as NASA promoting natural processes for solving some of earth's most troubling environmental problems.

Studies at NASA's John C. Stennis Space Center centered on the symbiotic relationship of the microbial/plant/animal world. Their findings helped to bring about a better understanding of the synergistic reactions taking place between plants and their root-associated microbes that create one of nature's most powerful tools for cleaning the environment.

During the past 30 years, the technology has advanced from laboratory and pilot-scale studies to general acceptance within the engineering community of the integration of biological processes and conventional wastewater treatment methods. Having gone through an evolution of technological descriptions (artificial marshes, constructed wetlands, etc.), the most generally accepted term is now phytoremediation. Operational systems are found throughout the world including single home wastewater treatment systems, municipal systems, industrial/chemical systems and aquaculture/agriculture operations.

In the early 1980s and again at the Stennis Space Center, NASA began studies using biological processes to improve indoor air quality in tightly sealed structures. Research revealed that interior plants and their microbes in the rhizosphere could biologically destroy toxic chemicals present in the ambient air. Again, the integration of natural processes and mechanical ingenuity has enhanced removal capacity. Today, technology exists that increases a plant's airborne toxin removal capacities by 200 times. Furthermore, these systems bioregenerate themselves to eliminate the costly filter replacement that plagues conventional filtering systems. Slow development of the technology has hampered its acceptance. However, with continued indoor air quality problems, increasing energy costs and the new threat of bio-terrorism, high efficiency plant-based filtering systems are poised to play a more integral role in the indoor environment.

As we now know, the interwoven efficiency of biological/mechanical treatment methods have greatly enhanced our ability to produce the goods that drive our modern society, yet preserve our land, air and waters for future generations. The emergence of ecological engineering is bringing about an acceptance and advancement of what is basically as old as the earth itself and has caused the engineering community to place a higher priority on protecting and preserving our natural resources.

Back to Top

TALKS

Aquatic Ecosystem Restoration in Abandoned Mine Lands of the Northern Anthracite Region, Pennsylvania: Selected Examples of Engineering Planning for Ecology

Kevin Luebke

U.S. Army Corps of Engineers

Baltimore, Maryland, USA

The effects of past mining practices have polluted more than 2,400 miles of the 54,000 miles (86,000 kilometers) of streams in Pennsylvania. There are approximately 200,000 acres of subsidence-prone land and approximately 250,000 acres of land impacted by mine sites. Most, but not all, of this pollution is from discharges from mines abandoned before passage of the 1977 Surface Mining Control and Reclamation Act. Approximately 1/6 of the Nation's abandoned mine land problems occurs within the Susquehanna River Basin (SRBC 2003). According to the Office of Surface Mining and Enforcement (2003), at current funding levels, it will take the Commonwealth approximately 60 years to reclaim priority 1 and 2 sites (public health and safety), but does not include priority 3 sites (environmental degradation). As part of an effort to assist the Commonwealth of Pennsylvania with reclamation of priority 3 sites, the U.S. Army Corps of Engineers (USACE) has partnered with PADEP and several grass-roots organizations to reclaim several hundred acres of AML and several miles of stream within the Lackawanna River and the Nanticoke Creek watersheds. In order to justify USACE involvement, a thorough understanding of ecosystem benefits in relation to engineering solutions of AML problems needs to be understood by both engineers and ecologists.

Multi-soil-layering System for Upgrading the Septic Tank Leachfields Systems

P. Boonsook ¹, S. Luanmanee ², T. Attanandana ¹ , P. Itsara ², T. Masunaga ³ and T. Wakatsuki ³

¹Department of Soil Science, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand; ² Soil Science Division, Department of Agriculture, Bangkok 10900, Thailand; ³Faculty of Life and Environmental Science, Shimane University, Matsue, Japan

Multi-Soil-Layering (MSL) systems have physical structure to enhance permeability of wastewater and mechanisms to prevent clogging and to enhance the purification functions of soil resource, such as BOD/COD decomposition, nitrogen and phosphorus removal, and the decomposition of the other pollutants in wastewater. Two MSL systems were constructed at Kasetsart University, Bangkok, which had been used from 1996 through 2001. Tank A was used as a principal research unit whereas tank B was operated 11 months during 4 years. The loading rate of combined toilet and cafeteria wastewater varied from 100 to 600 l m^-2 d^-1 under various aeration condition. MSL system could treat wastewater with mean values of COD K₂Cr₂O₇ 330 mg l^-1, BOD₅ 116 mg l^-1, TN 172 mg N l^-1and TP 17.0 mg Pl^-1 to following removal efficiency, i.e., COD 74.1%, BOD₅ 81.2%, TN 54.9% and TP 66% respectively. Aeration at a rate of 20,000 l m^-3 d^-1 for 3 days alternated with 2 months of non-aeration was appropriate and effective for enhancing COD, BOD₅, TN and TP removal. The removal percentage of COD, BOD₅, TN and TP at values of 73.3, 92.2, 65.3 and 83.0, respectively, were recorded. After using wastewater treatment for three years, soil and zeolite (clinoptilolite) materials used in MSL were analyzed to calculate material balance. Because of absorption and nitrification, upper layer of MSL showed very low pH (H₂O) 3-4. Soil layer accumulate organic matter up to 6%. Nitrogen (NH₄⁺-N), phosphorus, exchange K and iron oxide are accumulated considerably in zeolite layer.

Key words: domestic wastewater, high performance septic tank systems, multi-soil-layering system, zeolite

Remediation of a Sewage-laden Canal with Restorer Technology in an Urban Area of Southeast, China

Michael Shaw, Erica Gaddis Brown

Ocean Arks International

Burlington, Vermont, USA

Restorer Technology is ecologically engineered for the remediation of polluted water. As floating islands, Restorers provide diverse habitats that host a community of organisms. Restorers also circulate water and provide supplemental aeration. The floating islands can be arranged on a water body in many shapes making them a particularly attractive technology for improving the capacity of existing water bodies to remove organic matter, nitrogen, and pathogens.

The flexibility of the technology is evidenced by an application to polluted urban canals in Southeastern China. A large city uses a canal system, totaling over 80 kilometers, to collect sewage, commercial wastewater and stormwater and flush it to the Min River. The municipal government found it to be prohibitively expensive to re-sewer the affected sections of the city.

A 500-meter linear Restorer was installed along a highly polluted tributary canal in the summer of 2002 to demonstrate the capacity of the technology to remediate the problem in situ. The canal receives ~750,000 gallons per day of sewage and stormwater runoff. The floating Restorer supports over 12,000 plants of 20 native species. The system also includes fabric media as attached growth surface area, recycle to an anoxic zone, a fine bubble aeration system, and automatic dosing of beneficial bacteria.

The Restorer has successfully reduced odors, eliminated floating solids, and improved the clarity of the water and aesthetics of the neighborhood. Water has reached secondary effluent standards for several parameters throughout the canal and full compliance is expected by April 2003.

Growth of Benthic Algae on Dairy Manure

Walter Mulbry*, Elizabeth Westhead, Carolina Pizarro, Ann C. Wilkie

*USDA/ARS Animal Manure and By-Products Laboratory

Beltsville, Maryland, USA

Conservation and reuse of nitrogen (N) and phosphorus (P) from animal manure is increasingly important as producers try to minimize transport of these nutrients off-farm. An alternative to land spreading is to grow crops of algae on the N and P present in the manure. The general goals of our research are to assess one algal production technology, termed algal turf scrubbers (ATS) to recover nutrients from animal manures. The objective of this study was to assess algal growth, nutrient removal, and nitrification using higher light intensities and manure loading rates than in the previous experiments. As daily loading rates increased from 0.8 to 3.6 grams of total nitrogen per day, algal production increased from 7.6 to 16.2 grams dry weight per day, and algal N and P content increased from 4 to 7% and 1 to 1.5%, respectively. In the best case, algal biomass grown on dairy manure had a crude protein content of about 44%. At a dry matter yield of 16 g/ sq.meter-day, this is equivalent to annual uptake rates of 4090 and 876 kg/ ha-year for N and P, respectively. Compared to the N and P uptake of a conventional corn/rye rotation, an algal scrubber system operating 8 months of the year would require only about 13 % of the land area to utilize the equivalent dairy manure N and P.

Restoration of Mine Drainage Polluted Streams Through the Production of a Marketable Iron Oxide Product

Robert Hedin

Iron Oxide Recovery, Inc.

Pittsburgh, Pennsylvania, USA

Discharges from underground coal mines often contain excessive concentrations of ferrous iron. Where the flows are large and the water is untreated, the damage to receiving streams can be devastating. Treatment procedures have been developed in the last 15 years that utilize passive chemical and biological processes. Most of these treatment systems consist of sedimentation ponds, where a majority of iron precipitates, and constructed wetlands, where the water is polished. When properly applied through proper design and sizing, the technology has proven very reliable for iron-contaminated waters. The treatment of large discharges (> 2,000 L min^-1) has been delayed in many cases because of concerns about the long-term management of iron sludge deposits. Since 1995, we have been investigating the marketability of an iron product produced from passive mine water treatment systems. The viability of the idea was established in 2001 when 500 tons of a mechanically dewatered product was sold to a pigment manufacturer. Current research is focusing on passive dewatering techniques, increased processing, and increased product quality. If profitable production of a marketable iron product can be achieved, concerns about the long-term operation and maintenance of large passive treatment systems should lessen. The technology has the potential to make the restoration of AMD-polluted streams more cost-effective and practical.

Experimenting with coal combustion products as wetland treatment liners

Cheri R. Higgins², Li Zhang¹, Changwoo Ahn³, and William J. Mitsch²

Olentangy River Wetland Research Park¹, School of Natural Resources and Environmental Science Graduate Program, The Ohio State University², The University of Illinois, Urbana³

A three-year research project is being conducted to test the efficacy of using FGD coal combustion products as liners in shallow surface water treatment wetlands used to treat agricultural and municipal effluent. At the Olentangy River Research Park near the main campus of Ohio State University, four medium-scale (3m x 7.8m x1.5m) pilot wetlands have been constructed, two lined with clay and two lined with FGD material. The four basins were planted with Scirpus fluviatilis and Schenoplectus tabernaemontani. This is after several years' experiments with wetlands at 1 m² size published before by our research team. Surface water and groundwater quality (conductivity, redox, pH, DO, TOC, turbidity, total phosphorus, nitrate+nitrite-nitrogen), vegetative biomass, and chemical content of plant material have been sampled weekly for the first 0.5 year of the study after 1 year of experimental construction. Surface water quality was not different between FGD-lined and clay-lined basins in year one of the experiment (2001). Early leachate samples (in April, 2001) from the FGD-lined wetlands contained significantly higher Na, K, Ba, and Cl concentrations and a higher pH than samples taken in the clay-lined wetlands. During the first growing seasons (2001) Schenoplectus tabernaemontani biomass was significantly less in the FGD-lined basins than the clay-lined (F= 0.00), but Scirpus fluviatilis biomass was not different (F= 0.057). Biomass was not different for either species in FGD-lined verses clay-lined basins in the second growing season (2002)(F=0.23, 0.094). In the final analysis we hope to make a statement about the usefulness of clean coal byproducts as treatment wetland liners.

Factors Contributing to the Optimization of Tritium Phytoremediation at the Savannah River Site, SC USA

Daniel R. Hitchcock

USDA Forest Service

Center for Forested Wetland Research

New Ellenton, South Carolina, USA

Current activities at the Savannah River Site (SRS), formerly a Cold War nuclear production site, include environmental remediation and restoration. Specifically, the U.S. Department of Energy (DOE), the Westinghouse Savannah River Corporation (WSRC), the USDA Forest Service (FS-SR), and the University of Georgia's Savannah River Ecology Lab (SREL), are working in collaboration to design, operate, maintain, and monitor a phytoremediation irrigation system for the removal of low-level tritium from groundwater at SRS. A sprinkler irrigation system is being utilized on a 22-acre upland forested area for the distribution of tritiated groundwater seep discharge that is collected by a pond before it can ultimately reach the Savannah River. Irrigation scheduling for the phytoremediation system is typically based on continuous soil water deficit calculations using observed rainfall data and estimated evapotranspiration. In situ measurements at the project area include soil water content, soil water tension, and water table depth. Vadose zone soil water samples are also collected for tritium analyses. Tritium mass balance calculations have been used to estimate remediation efficiencies. Complex hydrological, biogeochemical, and ecological factors, as well as operations strategies, influence remediation system success. Factors that contribute to tritium remediation efficiencies, including relationships with irrigation volumes and frequency, as well as soil and vegetation types and characteristics within irrigation plots, are being evaluated. Related studies associated with the tritium phytoremediation project include vadose zone transport modeling, the exploration of winter evapotranspiration rates in upland forested areas, and the determination of tree health impacts from remediation using fluorometry. Data analyses from this project may aid in developing design criteria for future phytoremediation systems at SRS and other nuclear facilities.
Using Iron Amendments to Reduce Net Mercury Methylation in Wetland Sediments: Evidence from Models, Pure Cultures and Sediment Slurries

Anna S. Mehrotra*, Alex J. Horne, David L. Sedlak

*Department of Civil and Environmental Engineering

University of California

Berkeley, California, USA

One potential drawback of wetland construction and restoration is the formation of monomethyl mercury. We are investigating the use of iron amendments to wetland soils as a technique for reducing mercury methylation. Specifically, we hypothesize that the addition of ferrous iron decreases sediment sulfide activity, and therefore decreases the concentration of the bioavailable dissolved Hg(II)-S(-II) complexes (Hg(HS)₂⁰ and HgS_(aq)⁰) and net mercury methylation rates. We have used a combination of chemical equilibrium speciation models, pure Desulfobulbus propionicus cultures and sediment slurries to test this hypothesis. Chemical models suggest that increasing the concentration of Fe(II) in sulfidic waters does decrease the concentration of bioavailable, dissolved mercury complexes. Results from the pure cultures show that net mercury methylation decreases along a gradient of increasing [Fe(II)], with 70 to 90% less methylation in cultures amended with 10^-2 M FeCl₂ relative to 10^-6 M FeCl₂. Results from slurries with estuarine wetland sediments also show that net mercury methylation decreases along a gradient of increasing amounts of added Fe(II), with methylation in slurries amended with 4 mmol g^-1 Fe[II] 25 to 80% lower than methylation in unamended slurries. In both the pure culture and sediment slurry experiments, measured sulfide and filtered inorganic mercury suggest that the Fe(II) effect is, in fact, due to decreases in free sulfide activity and the concentration of dissolved inorganic mercury. In conclusion, although it seems that iron amendments may decrease mercury methylation in wetland sediments, results from wetland mesocosm experiments in progress will be important for verifying their efficacy.

A Wine Idea: Treatment & as the Entryway into Winery Tasting Rooms

Alex J. Horne

Ecological Engineering Group

Department of Civil & Environmental Engineering

University of California

Berkeley, California, USA

Ecological engineers and birdwatchers like constructed treatment wetlands of almost all kinds but the general public and most civil engineers remains unconvinced. One common question is "Will it smell?" How can one answer such a question with a simple no when anoxic soils (and the possibility of hydrogen sulfide generation) define wetlands? Many constructed wetlands have zero aesthetic appeal since most waste treatment facilities do not employ landscape architects. Over the last few years I have designed several wetlands to treat winery waste. Since land in wine country is usually very expensive the size of the wetland footprint is important. In addition, the wetland cannot be hidden from the public. Winery waste is unbalanced (high in C, low in N & P) and has a very high BOD (2,500 - 10,000 mg/L) so anoxia and malodor are always possibilities. Treatment with an oxidation system must precede the wetland. Wetlands at Turner Road Winery (Lodi, CA; ~ 2 million cases/y) constructed in 1999 will be contrasted with the very green wetland proposed for a more normal sized winery (~10,000 cases/y) in San Luis Obispo CA that is now being designed. In this winery it is proposed that visitors cross the treatment wetland on route to the tasting (and purchasing) room. Smell and aesthetics will be very important so control of the redox potential above ~ - 100 mV is critical. The amount of labile carbon and thus plant types will be as important as the percentage of free surface water. However, more free water and more refractory carbon reduced the wetland treatment efficiency and increase the footprint (and cost). These competing processes must be reconciled.

Constructed Wetlands for Treating Processed Mine Water -an Irish Case Study

Aisling D. O'Sullivan*, Declan A. Murray and Marinus L. Otte

* Department of Botany

University College

Dublin, Ireland

Mine wastewater in Ireland is conventionally treated with costly chemical applications. Passive treatment systems, employing both biotic and abiotic processes, are recognized as an economically feasible, ecologically acceptable treatment technology worldwide. Most of these systems have been applied to domestic wastewaters or abandoned mine waters for the primary purpose of removing nutrients or metals, respectively. Two experimental-scale treatment wetlands were constructed and monitored at an active lead/zinc mine (Tara Mines) near Navan in Ireland, to treat mine seepage with elevated sulfate (and metal) levels. Each system comprised three 12 m² (2 m depth) in-series surface-flow cells containing spent mushroom substrate (SMS) and an inert gravel in a ratio by volume of 1:6 (inflow and outflow, 30 cm depth) and 1:3 (vegetated, 50 cm depth). Typical aqueous concentrations of 830 mg L^-1 sulfate, 0.15 mg L^-1 lead and 2.0 mg L^-1 zinc entered the treatment wetlands at a flow rate of 650 mL min^-1. Anaerobic substrates, containing indigenous populations of sulfate-reducing bacteria, were conducive to biological reduction of sulfate to sulfide. Sulfide subsequently precipitated with metals under alkaline conditions. Monitoring of these wetlands over a 2-year period showed successful removal of sulfate (29 g m^-2 day ^-1 (69%)), lead (6.6 mg m^-2 day ^-1 (64%)), and zinc (70 mg m^-2 day ^-1 (98%)). All the interacting processes within the wetland ecosystems are currently being elucidated and quantified using a system dynamic model. Colonizing macroinvertebrates, macrophytes, algae and microorganisms also contributed to development of diverse ecosystems and a successful treatment process.

Inactivation of waterborne pathogens in engineered and natural systems

Kara L Nelson

University of California

Berkeley, California, USA

Engineered natural systems can be an ecological option for treating municipal and agricultural wastewater as well as storm water runoff. Wastewater stabilization ponds have a long history of use for treating wastewater both in industrialized and developing countries, and more recently constructed wetlands have been used around the world for improving water quality. In many cases, one of the treatment goals is the removal or inactivation of waterborne pathogens. Inactivation of pathogens occurs both in the water column and, for pathogens that are removed by sedimentation, in the sludge layer. Experimental results on the inactivation of pathogens in the sludge layer of pond systems in central Mexico will be presented. Based on these results, safe management strategies for reusing pond sludge as a soil amendment will be proposed. Current experiments on pathogen inactivation by sunlight-mediated processes in the water column will also be described.

Studying the Effect of Macrophyte Transpiration and Harvesting on Nitrate Concentrations in Wetland Treatment Systems

Jay F. Martin

Ecological Engineering Program

Department of Food, Agricultural & Biological Engineering

The Ohio State University

Columbus, Ohio, USA

Different amounts of biomass were harvested from Typha latifolia L. specimens to create three treatments of varying transpiration rates. One goal of the experiment was to test for effects of macrophyte transpiration on nitrate removal from wetland treatment systems. A second goal was to assess the short-term impacts of biomass harvesting upon the ability of wetlands to reduce nitrate concentrations. Harvesting and the resulting different rates of transpiration explained between 10 and 38% of the variation in nitrate reduction during the 10-day experiment and had significant effects upon nitrate concentrations. Greater rates of harvesting and lower rates of transpiration resulted in decreased reductions of nitrate in the surface water of the microcosms. During the first four days of the experiment 70% and 85% rates of aboveground harvesting reduced transpiration by 63% and 91%, respectively. These changes lead to respective declines in nitrate reduction of 16% and 31% compared to unharvested treatments. Differences in nitrate reduction between the treatments were minimal in the later days of the experiment as nitrate concentrations decreased. Results support the hypothesis that water movement due to plant uptake contributes to nitrogen removal and offers a partial explanation to increased nitrogen removal in vegetated wetland treatment systems. Decreased reduction of nitrate with greater harvesting demonstrates potential negative impacts on water quality improvement when using wetlands as bio-energy production systems.

Effectiveness of Engineered Wetland Systems (EWS's) in the Treatment of Anaeorobically Pre-treated Domestic Wastewater

Stephen E. Mbuligwe

Department of Civil and Environmental Engineering

Louisiana State University

Baton Rouge, Louisiana, USA

A study was carried out to assess the effectiveness of engineered wetland systems (EWSs) in the treatment of domestic wastewater pre-treated in an upflow anaerobic sludge blanket (UASB) system. Relative advantages of using different wetland plants were also assessed. The EWS had three units using river sand media. One bed was left unplanted and used as a control while the second and third beds were planted with cattail and coco yam plants, respectively.

The EWS was able to remove reasonably well phosphorus, sulphate, ammonia, and COD. It, however, performed poorly with respect to nitrate removal. Mean removals of phosphorus were 51% for the control unit, 69% for the cattail unit, and 75% for the cocoyam unit. Mean removals of sulphate were 46% for the control unit, 72% for the cattail unit, and 77% for the cocoyam unit. Mean removals of ammonia were 63% for the control unit, 74% for the cattail unit, and 75% for the cocoyam unit. Mean removals of COD were 65% for the control unit, 79% for the cattail unit, and 75% for the cocoyam unit.

This study demonstrated that the EWS can effectively treat anerobically pre-treated UASB effluent. As such, when coupled to a UASB it is a promising alternative to the traditional septic tank/soakaway - coupled systems widely used for treating domestic wastewater in developing countries. This study reaffirms the accepted notion that wetland plants influence the performance of wetland systems, and that it is advantageous to select wetland plants in accordance with treatment goals.

Bioengineering Stabilization of an Eroding Streambank along a Sanitary Landfill, Mill Creek, Cincinnati, Ohio

Kirk Barrett, PE, PWS¹ and Krista Rienhart²

¹ Meadowlands Environmental Research Institute, Rutgers University, Newark, New Jersey, USA

²The Bioengineering Group, Inc., Salem, Massachusetts, USA

An eroding and unstable streambank of Mill Creek in Cincinnati, Ohio, USA threatened to uncover waste contained in the adjacent Center Hill Landfill. The eroded bank was approximately 8 m (27 ft) high and 183 m (600 ft) long. The bank contained an existing leachate collection system located atop a clay soil layer that was both expensive to maintain and beset by mechanical problems. The clay was overlain by highly permeable, loosely compacted sandy, gravelly soils mixed with landfill materials.

The City of Cincinnati's Office of Environmental Management desired a bioengineering-based solution because of its ability enhance water quality, promote wildlife habit and increase aesthetic value. The bioengineering design featured the use of live poles, brush layers, geogrid lifts, live staking, and a brush fascine. Phreatophytic (highly water consuming) vegetation was incorporating with a new leachate collection system to intercept and transpire leachate from a gravel collection trench. Construction was completed in Spring 1999. Since then, brush vegetation has become vigorous and there have been no erosion problems. The City views the project as a success.

Assessment of Geomorphologic and Hydrodynamic Variable Before and After the Removal of a Low Head Dam

Tim Granata, Fang Cheng, Matthew Nechvatal

Ecological Engineering Group

Civil & Environmental Engineering Program

The Ohio State University

Columbus, Ohio, USA

The Saint John's Dam, on the Sandusky River in northern Ohio, was removed in the winter of 2003. The removal was sponsored by the State Scenic Rivers Program since the river is designated as a State Scenic River, and is part of an important watershed in the Great Lakes, flowing into Lake Erie. The 2.5 high, 30 m wide dam had a backwater (reservoir) of over 20 km which inundated numerous riffle-pool reaches upstream. In this talk, the removal process will be illustrated and data will be presented to compare flow and morphological changes that resulted in the river channel and floodplain as a consequence of the dam removal.

Evaluation of an Ecological Engineering Approach to Shoreline Restoration at Loyola Beach, Texas

Kim Jones, P.E., Emile Hanna, D. Tilley

Department of Environmental Engineering

Texas A&M University

Kingsville, Texas, USA

Loyola Beach located in Kleberg County, Texas has experienced accelerated rates of erosion along its 1500 feet of shoreline, claiming as much as 15 feet of land over a several year period. A 600 foot concrete seawall has been constructed at Loyola Beach to protect the Kaufer-Hubert Memorial Park shoreline from further erosion, however Park administrators are investigating alternatives including ecological engineering approaches to mitigate additional shoreline loss. Driven by a rising sea level, large storms, flooding, and powerful waves, many beaches along the US coastline and the lakes' shorelines are being eroded. Various methods are being evaluated to control the erosion that is occurring to the beaches, and one of the most promising approaches is a design based on ecological engineering principles.

An ecological engineering approach focuses on a structure that is aesthetically pleasing, provides natural shoreline habitat, and serves as a low-cost alternative for future mitigation projects.

The shoreline restoration project includes a unique design incorporating natural fiber mats, local stone and native plants to create a coastal area providing erosion protection, that blends with the natural surroundings, providing ecological habitat. Soft sediment thickness, penetrometer testing data, soil moisture, and soil shear strength measurements will be correlated with measured erosion rates and evaluated along the shoreline locations. The ecological project will be assessed through the geotechnical measurements including: moisture content, bulk density, grain - size distribution analysis, plasticity index, and shear strength before and after construction. Shoreline engineering surveys have been completed to determine the erosion rates that have historically occurred on the project area, and to serve as a baseline for evaluation of the ecological structure. The geotechnical parameters and vegetation establishment will be evaluated for their use in prediction of the long term stability of the ecological engineering structure and a model for erosion mitigation assessment.

Application of Acoustic Doppler Current Profilers to Measurement of Water Flow Patterns in Inland Waters

F. D. Shields, Jr., J. R. Rigby

National Sedimentation Laboratory

Water Quality and Ecological Processes Research Unit, USDA, ARS

Oxford, Mississippi, USA

In natural waterbodies or constructed systems designed to emulate natural regimes, water depth and velocity vary continuously in space and time. Knowledge of temporal or spatial water flow patterns may be required for assessing pollutant transport, processing time, retention potential, or habitat quality. Some workers have suggested metrics based on velocity or depth gradients to quantify habitat quality, with increasing quality associated with increasing levels of physical heterogeneity. Existing tools for studying flow patterns consist of numerical models that are imperfect representations of reality and field measurements that are slow and difficult. Acoustic Doppler current profilers (ADCP), originally developed for measuring velocities in marine environments, have been refined to allow measurement of depth and velocity profiles in slow (~ 1 cm s^-1), shallow (~ 30 cm) flows typical of wetlands and small rivers. Velocity profiles may be obtained that include three-dimensional velocity measurements at 1-cm vertical intervals. ADCP systems may be deployed on moving boats or rafts because they obtain positional data from compasses, echoes from the solid boundary (bed), and global positioning systems. This technology is an important addition to existing methods for simulating or measuring flow patterns. However, existing software for reducing and processing the voluminous data output by ADCP are tailored for computing water discharge rather than metrics of habitat quality such as vorticity and circulation. Herein data are presented that were collected using a commercially-available 1200 kHz ADCP and reduced using specially developed software. The influence of woody debris and channel planform on velocity-based habitat metrics is examined.

A Linear Systems View of Non-Steady State Flow and Reaction in Wetlands

James N. Carleton

US Environmental Protection Agency

Washington, DC, USA

Previous investigations have explored how steady-state flow in treatment wetlands can be approximated as stochastic-convective, and reaction modeled using first order kinetics averaged over an ensemble of stream tubes with different velocities. This exercise extends these concepts to the case of non-steady state flow and temporally varying inlet concentration. The essential construct which makes this approach feasible is definition of a set of reference (steady) state conditions under which the residence time distribution (RTD) and stream-tube specific rate constants are defined. Residence time in any stream tube under non-steady flow is treated as a linear function of its reference-condition residence time, and the overall wetland retention time under both mean and varying flow regimes. Outlet concentration (C_o) is found by convolution of the reaction term with a varying inlet concentration (C_i) function, and addition of a constant background concentration. For real-world flow and concentration data collected at discrete points in time, integration for C_o can be approximated using algorithms which make use of linear interpolation to approximate C_i and velocities at intermediate points in time. The approach is examined using data from the literature.

Hydraulic Considerations and Performance Modeling For Treatment Wetland Design

Christopher H. Keller, P.E.

CH2M HILL

Tampa, Florida, USA

Treatment wetland design criteria can be developed based upon a review of performance data from existing operational systems and the subsequent calculation of pollutant removal rates. These rate constants are often applied to simple, plug-flow design equations that estimate the wetland area required to achieve project objectives. However, hydraulic tracer studies have shown that plug-flow conditions are rarely achieved for most operational systems. Without a detailed understanding of the internal hydraulic characteristics of the operational systems used to develop design criteria, and the selection of an appropriate design model, effluent water quality predictions may be compromised. To optimize treatment wetland design criteria, tracer studies can be conducted to more accurately characterize wetland hydraulics. Tracer study results can be incorporated into more suitable sizing models that increase the designer's ability to predict wetland performance under a realistic range of operating conditions. This presentation reviews tracer study theory and practice, presents alternatives to the plug-flow design model, and examines the relationships between pollutant loading rate, wetland size, and effluent quality.

Indirect Effects in Transport Networks

David K. Gattie¹ and Stuart Borrett²

¹Biological & Agricultural Engineering, The University of Georgia, Athens, GA, USA

²The Institute of Ecology, The University of Georgia, Athens, GA, USA

Network organization of complex systems propogates indirect interactions. Network Environ Analysis is extended to assess the presence of indirect interactions within the network organization of complex systems. Direct transactions establish an initial pattern over which more complicated relations can form in transport networks; however, determining the net relation between components can be quite difficult. Here, we use environ analysis, a type of network analysis, to demonstrate several possible indicators of network indirect effects in ecological flow networks. The fundamentals of this analysis offer a quantitative tool for assessing the holistic behavior of a system resulting from interactions of components that appear disconnected in traditional flow models of conservative quantities. The importance of the relations of these seemingly disconnected components is discussed.

Predictive Biology for Ecological Engineers

Arthur T. Johnson

Biological Resources Engineering Department

University of Maryland

College Park, Maryland, USA

Biology for engineers needs to take a different form compared to biology for biologists. Engineers need to be able to formulate solutions to problems involving living organisms, and this emphasis on utilization requires that typical responses should be known.

The biology that is taken by ecological engineers should be able to meet three objectives:

1. it should allow for the creation of useful projects or processes

2. it should allow information known about a familiar organism to be transferred to an unfamiliar organism.

3. it should help to avoid the unintended consequences incurred when dealing with any biological system.

A course based upon these three objectives has been taught at the University of Maryland, and experiences gained are helping the course to improve. This course can be used as a model for other ecological engineering curricula.

Lacandon Maya agriculture: an ecologically engineered indigenous system

Stewart A.W. Diemont, Jay F. Martin

Ecological Engineering Program

Department of Food, Agricultural, and Biological Engineering

The Ohio State University, Columbus, Ohio, USA

The Lacandon Maya, an indigenous group in southern Mexico, have used polyculture cropping and ecological succession to produce food and other resources from the same parcel of land for hundreds of years without fertilization, pesticides or herbicides. They cycle fields through three stages of production starting with the milpa (grass stage), progressing to the acahual (bush stage), and then to the forest, before returning to the milpa.

Research conducted during the summer of 2002 indicates that the Lacandon rely on successional processes to maintain fertile soils and regenerate nutrient stores. After decades of use, the sampled milpa retained nitrate (23.3 mg/Kg) and phosphorus (7.8 mg/Kg) concentrations similar to fertilized fields. Furthermore, the acahual had statistically greater nitrogen and organic material concentrations than in the milpa fields (P < 0.05). This talk will focus on how the agricultural methods practiced by the Lacandon and other indigenous groups demonstrate ecological engineering principles.

How Improved Energy Efficiency Increases Energy Use

Andrew Rudin

Energy Management

Melrose Park, Pennsylvania, USA

My paper will address the following negative characteristics of energy efficiency and offer alternative approaches that are more appropriate.

1. Technical fixes alone have not been sufficient to reduce our consumption of energy.

2. Environmental improvement is usually expressed as decreasing pollution rates. Improved efficiency, however, is expressed as a ratio, disconnected from a rate. The environment does not respond to miles per gallon or lumens per watt, it responds to gallons and kilowatthours.

3. Improved energy efficiency sets no limits on energy consumption. To optimize is not to minimize. Energy efficiency is a means without a goal.

4. The more energy we consume, the greater the savings resulting from improved energy efficiency.

5. Energy efficiency depends on obsolescence; buying increasingly efficient replacements justifies increases in material throughput.

6. Energy efficiency requires redundancy, not only in a final product that is more efficient than another, but in all preceding processes and products.

7. Within the logic of cost/benefit analyses, efficiency is based on the price of extracting energy resources, not on their replacement cost. Without limits, improved energy efficiency increases the likelihood of using more energy.

8. Energy efficiency shifts responsibility for energy use from individuals to technology. The more popular efficiency is, the less empowered and more dependent end users become. Improved efficiency instructs what to buy, not how to use it.

9. Energy efficiency is a source of energy, not an alternative.

The paper concludes by suggesting alternatives.

Rain Gardens/Bioretention: The Construction of a University Research Site

Rebecca Stack

Biological Resources Engineering Department

University of Maryland

College Park, MD, USA

 

The Chesapeake Bay has land development growth rates 2.5 times greater than population growth rates. Intrinsic to development is the expansion of impervious surfaces. Stormwater runoff from impervious surfaces diminishes water quality and alters the channel geometry as well as the biotic communities. Bioretention, or rain gardens, is an innovative technology to treat stormwater runoff. Bioretention, an aerobic gravity flow system with a combination of plants, soil and piping for drainage, is sized to treat one drainage acre or less to limit concentration of pollutants and erosive forces within the system and the potential for thermal pollution to receiving streams as water is released.

While laboratory research indicates the system's potential for pollutant removal rates are high, no field data during actual storm events exists. Research indicates the treatment efficiency would improve if design elements for denitrification were incorporated. No research exists on the self-organization of the ecology in these systems, nor the role the ecology may play in the system's functionality. To gather field data during actual storm events a research site was constructed on the University of Maryland Campus. The design of this Bioretention site was modified to control for ground seepage and measure flows into and out of the system. Two units were constructed to compare the existing design against one with a denitrification sump. The construction process of these units, the obstacles to completing such an endeavor on a university campus, and the opportunities such a research site presents will be discussed.

 

Ecological Engineering for the restoration of degraded watershed in tropical Asia and Africa

Toshiyuki Wakatsuki

Shimane University

Matsue, Japan

Since tropical Asia has been widely developed intensive and sustainable lowland irrigated rice fields, i.e., sawah, or paddy, systems, fragile upland systems are the target to restore. To develop the technology to increase humus level in upland soils is the major target. Possible technologies to convert sludge and livestock wastes of low C/N ratio to stable and functional humus materials will be discussed. In tropical Africa, however, lowland sawah based rice farming systems are not common. Therefore, the mean paddy yield in West Africa has been stagnant at 1.3-1.5 t/ha during the past 30 years. In tropical Asia, the figure doubled from 1.8 t/ha to 3.6 t/ha in the same period. There exist numerous small inland valley swamps (IVS), in Africa. Total area of the IVS reaches 10 million hectares. Small sawahs can be developed in the IVS by simple and low cost eco-technology with farmer's participation. If floodplains and deltas are added, the total potential of irrigated sawah reaches 20 million ha. Since sustainable productivity of 1 ha of lowland sawah is equivalent to more than 10 ha of upland fields, because of wetland sawah systems and geological fertilization in watershed agroforestry. the development of 1 ha of sawah open the field for the afforestation in the degraded upland. Thus if we can develop 20 million ha of sawah in the next 50-100 years, we can open an afforestation area of 200 million ha. Apart from carbon sequestration, the forest also conserves soil and water and create fertile soil, which in turn make increase sustainable production of lowland sawah.

Back to Top

 

POSTERS

Soil development of two wetland creation areas at the Olentangy River Wetland Research Park in Columbus, Ohio

Chris J. Anderson, William J. Mitsch

School of Natural Resources

The Ohio State University

Columbus, Ohio, USA

Soil development was evaluated in two 1-ha wetland creation areas at the Olentangy Wetland Research Park in Columbus, Ohio. The experimental marshes (one planted and one unplanted) were created in 1993 and have been extensively monitored for various parameters including: water levels, prevalent vegetation and above ground biomass. In December 2002, a total of 102 soil samples were collected at sampling points established every 20 m using a 160 m x 200 m grid. At each sampling point, soils were sampled at two depths: 0-8 cm and 8-16 cm. Soil color, percent soil organic matter, and bulk density were compared to soil samples collected in 1993 and 1995 that used the same sampling points. The comparison showed changes in soil chroma and significant increases in percent organic matter since 1995. At 0-8 cm depth, the experimental wetlands increased from a mean of 6.2 + 0.4% organic matter in 1995 to 10.1 + 1.2% in 2002. Bulk density increased significantly for soils at the 8-16 cm depth (1.03 + 0.04 g/cm3 in 1995 to 1.34 + 0.05 g/cm3 in 2002). Effects of vegetation type and above ground biomass on the development of wetland soils are also presented.

Minimal Treatment Performance by a Stressed Living Machine

David Blersch, Patrick Kangas

Biological Resources Engineering Department

University of Maryland

College Park, Maryland, USA

A small living machine was constructed at the Mars Society's Desert Research Station in southeastern Utah in order to experiment with wastewater treatment options. The station is occupied by crews of volunteers who simulate activities associated with a future Mars landing. While the ultimate goal for the living machine is to treat wastewater generated by crews, the system at present is too small and it is intended to be used for experimental purposes only. The living machine consists of a trickling filter tank and four aerobic aquatic tanks. The tanks are arranged in series and located in a cylindrical greenhouse 3.5 m long by 4.3 m in diameter. The living machine is preceded by two buried tanks that act like anaerobic septic tanks outside the greenhouse. The total tank volume inside the greenhouse is 0.90 m3 and the combined volume of the two buried tanks is 0.95 m3. The living machine was connected to the habitat in November 2002 in order to treat wastewater from the toilet ("blackwater") and from the sinks ("greywater") and to recycle the treated wastewater back to the toilet for flushing. It quickly became overloaded due to a high loading rate and due to a lack of heating in the greenhouse during the winter months. The higher aquatic plants in the system were killed, the aerobic tanks turned anaerobic due to the overloading and a strong odor developed in the greenhouse. However, despite all of the stresses, the living machine maintained a minimal treatment performance as evidenced by a reduction in chemical oxygen demand of the wastewater as it passed through the system. The biochemical basis of this minimal treatment is explained as an example of the resilience of the living machine ecosystem. The system has been taken off-line and it is being redesigned in an effort to increase the treatment capacity

Numerical Modeling of Sediment Transport Associated with Dam Removal and the Related Geomorphic Effects

Fang Cheng, Tim Granata

The Ohio State University

Columbus, Ohio, USA

Dam removal has been proposed by scientists and resource managers as a strategy for river restoration. Reservoir sediment flushing downstream is one of the major geomorphologic effects associated with dam removal. It is well known that sediment pulse has big influence on downstream and upstream river channel and bed forms. Downstream fish habitat and the aquatic ecosystem are controlled by the riverbed substrates composition, channel form and hydraulic conditions. River hydraulic characteristics and sediment transport interact and influence each other, and eventually have effects on the river ecosystem. In order to fully understand and accurately estimate the effects of dam removal, it is necessary to understand the dynamics of sediment transport associated with dam removal. Primary concerns about dam removal include direct and indirect effects of exposure to increased total suspended sediment (TSS), disturbance of fish habitat because of sediment deposition downstream and effects of sediment transport on adult walleye migration upstream. A numerical model of sediment transport associated with dam removal will be developed based on the existing modeling software MIKE 11. The model will be customized for the case of Saint. Johns Dam on Sandusky River, OH. For model calibration, field data (e.g. cross sections, bed load, TSS, velocity) will be collected before the dam removal, during dam removal and immediately after dam removal. A complete understanding of the effects of dam removal will overcome the simplistic view of removing dam and enhance the dam removal decision-making.

Design, Self-design, and Redesign of a Newly Constructed Treatment Wetland in an Agricultural Watershed

Daniel F. Fink, William J. Mitsch, Ph.D.

The Ohio State University

Columbus, Ohio, USA

This study examines the development of a constructed emergent marsh designed to reduce nutrient loads from an agricultural watershed in central Ohio, USA. The system includes a 1.2-ha wetland basin receiving water from a 17-ha watershed, 83.5% of which is intensive row-crop agriculture. Over the two years of this study, there were changes in the wetland design that lead to significant differences in hydrology, community development, and function. In the second year, tunneling muskrats connected two previously separate basins within the wetland complex. This tunneling nearly drained one of the basins and also allowed floating propagules to pass easily from one basin to the other. This change in design also affected the subsequent development of both the plant community structure and the water quality functions of the wetland. Concentrations of nitrate-nitrite, SRP, and TP declined on average 43%, 36%, and 59% respectively between the inflow and outflow of the wetland. There was a significant change in the rate of nutrient retention between 1998 and 1999. The concentration at the outflow was lower by 7% for NO₃^- and 19% for SRP, while TP increased by 33%. Finally, suggestions are presented for additional changes in the design of the wetland to improve its' efficacy as a treatment wetland for controlling nutrient runoff. This study demonstrates how the effects of self-design must be allowed for in the original design of a treatment wetland, and also how it can lead to the development of a more functional ecosystem.

Carbon Monoxide Removal Rates of Biofilters

Priti Ganeshan, David Tilley

Biological Resources Engineering Department,

University of Maryland

College Park, MD, USA

Carbon monoxide (CO), a product of incomplete burning of hydrocarbon-based fuels is a colorless, odorless, poisonous gas. CO inhibits the blood's oxygen carrying capacity affecting healthy individuals. Its presence in the atmosphere lowers OH- decreasing the atmosphere's capacity for oxidizing other greenhouse gases. Soils microorganisms are recognized as the second largest sink for eliminating CO from the lower atmosphere. Microbially-mediated biofiltration of CO was investigated for its potential to oxidize CO. Six bench scale biofilters (1 m x 6 cm) were constructed and filled with either clay gravel or compost as media. A microbial inoculum was developed from local urban soils and added to each media. CO contaminated air, pumped through the units from below, was measured at 25 cm intervals along the direction of flow including exit. The CO elimination dynamics of the biofilters will be presented. From an industrial ecology perspective biofiltration reduces air pollution for a small ecological footprint.

Flow and sediment processes in the Waterman Wetland

Jessica Healey, Tim Granata

Ecological Engineering Program

Ohio State University

Columbus, Ohio, USA

An innovative two-cell constructed wetland treatment system (CWTS) was designed to simultaneously treat nursery pad effluent high in nitrogen and stormwater run-off high in suspended solids in an urban/agricultural setting. The purpose of this study is to examine how forcing affects the CWTS's performance over time using high to medium resolution time series of ecological and environmental variables. Specifically, we intend to characterize flow and sedimentation dynamics in these two constructed-wetland cells. We hypothesize that the particle characteristics change as the water flows through the wetland cells, and that lower residence times will lead to washout. We also hypothesize that dense vegetation will reduce turbulent mixing during high-flow events, preventing resuspension of deposited material. Vegetation may also short-circuit the cells by redirecting flow. Sediment samples are being collected on a monthly basis, using sediment traps. Volume and wet weight of the samples are measured, and subsamples are used to calculate organic and inorganic weight. Particle size spectra are measured using a Malvern Mastersizer particle counter, and settling rates are determined in both static settling columns and in the Malvern Mastersizer. Composite subsamples will be analyzed for total carbon and total phosphorous. To partition phosphorous further, total orthophosphate, total hydrolyzable phosphorous, and total organic phosphorous will be measured on composite subsamples. Particle and phosphorous mass balances will be done by combining monthly data with suspended solid and flow data collected autonomously every 5 minutes at the inlets and outlets of the CWTSs.

Effects of water level and flow rate on wetland hydraulic efficiency

Jeff Holland, Jay Martin, Tim Granata, Virginie Bouchard, Martin Quigley

The Ohio State University

Ecological Engineering Program

Department of Food, Agricultural, and Biological Engineering

Columbus, Ohio, USA

Understanding factors that affect wetland hydraulics can lead to improved design and more effective management of treatment wetlands. Although the flow dynamics of a wetland are difficult to model or directly measure, the effects of flows on wetland efficiency can be determined using tracer studies and corresponding residence time distribution analysis.

We have begun research using a small constructed wetland with adjustable water levels and access to agricultural irrigation water to quantify the effects of different water levels and flow rates on treatment efficiency. At this site, dye tracer tests and water quality analysis can be performed to determine the effects of storm pulses on wetland dynamics.

Two preliminary dye tracer experiments were conducted at high and low water levels using simulated storm flow. The time of travel and mean detention time were greater at higher water levels, as a plug flow model would suggest. An inverse relationship, on the other hand, was found between hydraulic efficiency and prescribed water level. The high water level had a hydraulic efficiency of 27% and the low water level 58%. This trend indicates that although a deeper basin typically has greater detention capabilities, it may not use this greater volume as efficiently as a shallow basin. Replicates of these experiments are planned to verify these results and compare with observed water quality measurements.

Emergy Analysis of the Bolivian Forest System

Jose-Luis Izursa¹, David R. Tilley²

¹Marine Estuarine Environmental Science Program University of Maryland

²Biological Resources Engineering, University of Maryland, College Park, Maryland, USA

The forest of Bolivia cover 50% of the total land area (48,000,000 ha) and contain over 2.700 tree and shrub species. Dense lowland rainforests of the north-eastern third of the country are located in the Amazon basin. Bolivian forests comprise valuable commercial species, but are relatively inaccessible. Forest plantations cover only 40.000 ha, while 10,000,000 ha of forest are protected in a network of reserves. In 1996 total export of forest products was US$ 125 million, of which sawn timber was the main type. Bolivia imports a modest quantity of forest products, mainly paper. Bolivia also produces an enormous variety of non-wood forest products (Brazil nuts, palm hearts, rubber latex), mainly in the Amazon. A previous emergy analysis of Bolivia showed that in 1992 the country was losing in international trade at a rate of 5-to-1 (i.e., for every 5 emdollars of natural resources exported, Bolivia only received $US 1). We extend and update this previous emergy analysis to evaluate the vast forest resources of Bolivia and their role in contributing to the sustainable development of the country. The role of natural resources in developing countries, such as Bolivia, must be viewed as the basis to achieve ecological, economic, and social sustainability. Emergy evaluation provides an integrated tool for assessing the ability of nature to provide its 'free' services, and gives to decision makers a more holistic perspective for achieving a sustainable and ecologically balanced economy.

Transport Processes in Ecological Engineering Education

Arthur T. Johnson

University of Maryland

College Park, Maryland, USA

Complex interactions occurring in ecological systems often involve transfer of energy or mass. Understanding of these interactions cannot occur unless the underlying transport concepts are known.

Perhaps the most general means to approach transport processes is through analogical systems. This approach uses the concepts of effort and flow variables, resistance, capacity, and inertia in various combinations to specify the form of the process. Calculating or experimentally determining numerical values for system components then becomes a relatively easy detail.

Transport processes have been taught in this manner at the University of Maryland for several years. Students find this approach to be helpful in their first exposure to transport processes.

Treating and Utilizing Dairy Washwater with an Ecological System

Angelique M. Keppler, Jay F. Martin

The Ohio State University

Environmental Science Graduate Program

Columbus, Ohio, USA

Animal production facilities face challenges of minimizing costs and energy use while treating large quantities of wastewater. One alternative to traditional treatment facilities is a Living Machine. These ecological treatment systems have shown success in the treatment of municipal wastewater and may offer a more sustainable and cost-effective approach to treat animal production wastewater. Another promising alternative is to include aquaculture in such a system to utilize the wastestream as a resource to produce a value-added product. To test these ideas students in an ecological engineering design course constructed and monitored an ecological system to treat washwater from the campus dairy facility. The system consisted of six components, including an anaerobic tank, two aerobic tanks, a clarifier, an aquaculture tank, and a wetland microcosm. The overall goal was to use the washwater to support a food chain that would process nutrients, bacteria, and solids and terminate in the production of fish and vegetative biomass. During three weeks of operation, the system improved the water quality of dairy washwater (reductions of solids by 87%, organic carbon by 71%, total nitrogen by 85%, total phosphorus by 86%, BOD by 97%). The system also produced a 123% gain in fish biomass over 9 weeks, which was supported solely by the addition of wastewater.

Applications of Ecological Engineering Principles in Taiwan: the Protection of the Formosan Salmon

Jen-Yang Lin¹, Tsu-Chuan Lee¹, Yong-Fa Lin², and Shaw L. Yu³

¹Dept. of Civil Engineering, National Taipei Univ. of Technology, Taipei, Taiwan, ROC

²Shi-Pa National Park Administration, Taichung County, Taiwan, ROC

³Dept. of Civil Engineering, Univ. of Virginia, Charlottesville, VA, USA

The Formosan landlocked salmon (Oncorhynchus masou formosanus), an endangered species, is considered a national treasure to Taiwan and is one of the southernmost natural salmon populations in the world. Historically, the salmon were abundant in some streams in Central Taiwan with elevations between 1,450 to 2,500 meters above sea level. However, habitat degradation associated with excessive agricultural development, check dam construction for sediment control, as well as over-harvests caused a severe decline in the salmon population. A 1999 survey by the Taiwan government showed that the salmon population had declined to less than 800 individuals.

The proposed paper will describe an effort, which was initiated in 1999, by governmental agencies, engineers and scientists on Taiwan to save the species. The effort, called the Chichiawan Creek Restoration Project (CCRP), included the following components: 1)establishment of riparian corridors; 2)maintenance of salmon refuges and spawning sites; 3)construction of artificial pool habitats, and 4)restoration of fish passages over check dams. Examples of the engineering work include the construction of "emergency channels" for the salmon so that the fish can escape being flushed downstream by flood waters during typhoon events. Since the initiation of these protection efforts, several monitoring runs have been made to document the estimated salmon population, with one recent survey in 2002 showing a total population about 2,000.

In addition to reporting on the CCRP Project in detail, the paper will also provide a brief discussion of the current status of ecological engineering applications in Taiwan.

Two Years of Vegetative Data from Engineered Experimental Goose Exclosures on Mudflats of Kingman Marsh in Washington, D.C.

Peter May

Biological Resources Engineering Department

University of Maryland

College Park, Maryland, USA

The restoration of emergent tidal freshwater marsh habitat on the mudflats of Kingman Lake in 2000 provided an excellent opportunity to test the hypothesis that grazer effects may deflect the desired outcome of large scale marsh restoration efforts. The presence of a sizeable resident Canada goose population inhabiting the greens and open water of an adjacent public golf course was initially not taken into consideration when restoration designs were developed and implemented. A goose exclosure experiment was developed in the midst of the marsh restoration in the Spring of 2001, with emergent species composition and biomass recorded through two growing seasons. Data are presented on marsh macrophyte growth and survivability from two sizes of experimental exclosures, covering a total of 1,350m². These results have led to recommendations for improved marsh restoration techniques in the presence of resident goose grazing pressures.

Development of a Fast River Survey Method: A New Tool for River Restoration

Matthew Nechvatal, Tim Granata

Ecological Engineering Group

Civil & Environmental Engineering Program

The Ohio State University

Columbus, Ohio, USA

A novel new series of technological advancements in surveying Geographical Positioning Systems (GPS) and acoustic Doppler current profilers (ADCP) has reduced the size and weight of these components such that they can now be conveniently used for field measurements in rivers and coastal zones. We have interfaced a survey grade GPS with a shallow water (< 2 m) ADCP and mounted the system on kayak to provide real-time measurements of 3-D water velocities, water depth, channel cross-section, total discharge, and bed slope. These measurements are being used to rapidly assess changes in channel form and function before and after river restoration activities.

Greening Schools: Transforming Baltimore's Schoolyards

Susan Patz, William Stack

Baltimore City Department of Public Works and Bureau of Parks

Baltimore, Maryland, USA

Greening Schools: Transforming Baltimore's Schoolyards is a multi-layered project to restore Chesapeake Bay Watershed tributaries by replacing 6.75 acres of impervious surfaces with green landscapes at Baltimore City Schools. In addition to the physical restoration, the Department of Public Works has partnered with other municipal agencies, environmental educators, and local organizations to develop an education component inside the school walls, which includes both the school and neighboring communities. The integration of the physical watershed restoration measure with the education component gives students the opportunity to design and implement a restoration project- solving real world environmental problems in their own backyard and understand their connection to basin-wide watershed issues. This watershed restoration project will serve as an example of how existing urban settings can be modified to reduce pollutant transport and peak discharges to The Chesapeake Bay, thus protecting the health of both Baltimore streams and The Chesapeake Bay Watershed.

Effects of a Hypolimnetic Oxygenation System on Blue-Green Algae and Internal Nutrient Loading in A Eutrophic Drinking Water Reservoir

Rowan A. Roderick-Jones, Christina Toms, Dr. Alex J. Horne

Ecological Engineering

University of California

Berkeley, California, USA

The production of compounds such as geosmin and MIB by blue-green algae in eutrophic reservoirs is a serious problem for many drinking water utilities. Removal of these compounds through traditional water treatment technologies is often prohibitively expensive and unsustainable. One possible solution is to manipulate the ecology of the reservoir by hypolimnetic oxygenation. This may reduce blue-green algae populations by preventing the release of phosphate (a limiting nutrient) from the bottom sediments. In the spring of 2002, California's East Bay Municipal Utilities District (EBMUD) installed a hypolimnetic oxygenation system (HOS) in Upper San Leandro Reservoir (USL) to address taste and odor problems. To examine the effects of the HOS, we compared current conditions in the reservoir with data gathered prior to HOS installment. Water column samples were gathered from various depths at three different locations in the reservoir and analyzed for soluble reactive phosphorus (SRP) and nitrate. Blue-green algae filaments were counted in benthic samples from the same locations. Preliminary results indicate that between 1998 and 2002, hypolimnetic nitrate increased by an average of 0.170 mg-N/L while hypolimnetic SRP decreased by an average of 0.182 mg-P/L. After one year of HOS operation, benthic blue-green algae densities at sites near the HOS were, on average, 57.4% lower than those far from the HOS. We are currently analyzing more data to further quantify the effectiveness of the HOS. While these preliminary results are encouraging, the variability of natural systems necessitates future research to isolate the effects of the HOS.

Restoring the First Ecological Simulator

Gary Seibel, Patrick Kangas

Biological Resources Engineering Department

University of Maryland

College Park, Maryland, USA

H. T. Odum began electronic simulation of ecosystems in the 1950s. He constructed models as networks of basic electrical components that were analogous to ecological networks of biomass storages and material flows, such as carbon. These models, called passive analogs, were pieces of hardware, with the electrical components mounted on large circuit boards. Simulations were performed by wiring the network, connecting batteries and measuring flows and storages with milliammeters and voltmeters. This approach to ecological modelling was highly innovative and the passive analogs were actually an early form of the modern computer. Although Odum switched to operational analog computers for simulation in the late 1960s, the heritage of the passive analogs became embodied in the symbolic modelling language that he developed and used the rest of his life. In this presentation the restoration of one of Odum's original passive analogs is discussed. An effort is being made to replace missing and worn-out components with comparable, vintage parts from the 1950s as much as possible. The ultimate goal is to restore the model to working condition. Theory of passive analogs is reviewed and progress towards restoration of the circuit board is described.

Development of a General Ecological Model for the Sandusky Watershed

Cynthia Smith, Jay Martin

Ecological Engineering Program

Department of Food, Agricultural & Biological Engineering

The Ohio State University

Columbus, Ohio, USA

A general ecological model (GEM) was developed as part of a project to create a spatial watershed model to predict water quality and habitat change within the Sandusky River watershed (Lake Erie, Ohio). General ecological models permit simulation of habitat change within spatial cells by changing only model coefficients while maintaining the same model structure.

The general ecological model uses identical relationships and mathematics with variations in ecosystem-specific coefficients to simulate edaphic and vegetative processes characteristic of each ecosystem. Habitat types found in the watershed and included in the model are agriculture, forest and wetland. State variables common to these habitats included in the model are photosynthetic and non-photosynthetic biomass; organic and inorganic nutrients (N and P); and detritus. Previous studies provide ecosystem-specific coefficients for processes such as production, respiration, evapotranspiration, litterfall, decomposition, and herbivory. The model incorporates nutrient cycling through limitation and uptake characteristics of the dominant plants of the particular habitat. Forcing functions consist of climatic and hydrologic data including precipitation, sunlight, temperature, and water level. The model was calibrated and validated by comparing output to studies of similar ecosystems and data collected within the watershed. The final project will integrate the general ecological model with a hydrodynamic model to predict changes of water quality and habitat to evaluate land use policies within the watershed.

Pesticide Removal in Treatment Wetlands

Sarah Stafford

University of California

Berkeley, California, USA

Treatment wetlands have been proposed as a sustainable, cost-effective and ecologically-sound method for treating pollution from non-point sources. Effective removal of nitrate by means of denitrification has been demonstrated in treatment wetlands, making them an obvious choice for treatment of agricultural run-off. However, agricultural run-off often contains pesticides as well as nutrients, and the fate of pesticides in wetlands has been less thoroughly investigated. Several studies have reported removal of the herbicide atrazine in wetlands, mostly due to sorption followed by microbial degradation. However, the removals of many other pesticides in wetlands have not yet been evaluated. This poster will report on current experiments evaluating the sorption of an organochlorine pesticide, 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (DDE) and an organophosphate pesticide, diazinon, to wetland plant materials and sediments. Preliminary data suggest that both pesticides sorb effectively to bulrush, cattail and peat moss. Experiments are currently in progress to determine the partitioning coefficients of DDE and diazinon for the three different sorbents and to evaluate the removal of DDE and diazinon from the water column in mesocosm scale wetlands. These experiments will enable us to compare removal via sorption with removal via biological degradation and evaluate the feasibility of using a treatment wetland to remove diazinon and DDE from agricultural run-off.

Keywords: diazinon, DDE, "pesticide removal"

Narrow waveband reflectance of emergent macrophytes as an indicator of wetland water quality

David R. Tilley^a, Muneer Ahmed^b, Ji Ho Son^c, Harish Badrinarayanan^b

^aBiological Resources Engineering, University of Maryland, College Park

^bDepartment of Environmental Engineering, Texas A&M University—Kingsville, Kingsville, TX 78363

^cDepartment of Environmental Engineering, Pukyong National University, Pusan 608-737, Korea

Narrow spectral band reflectance indices of two emergent macrophytes (Typha latifolia and Borrichia frutescens) were found to correspond to changes in water column total ammonia (TA=NH3 + NH4+) of a constructed treatment marsh (8 ha) in semi-arid south Texas, USA. A handheld hyperspectral radiometer measured plant leaf reflectance across the visible (VIS, 300-700 nm) and near-infrared (NIR, 700-1100 nm) spectrum during the mid-growing season (July-August).  Reflectance of the two species and water quality (TA; total phosphorus, TP; salinity, S) were measured along a dynamic treatment gradient from wetland inlet to outlet.  Mean TA concentration was 1.22 mg-N l^-1 ranging between 0.92 and 1.71 mg-N l^-1.  Salinity fluctuated between 2.5 and 4.5 ppt, while total phosphorus was between 0.01 and 0.86 mg-P l^-1.  A multilinear regression equation containing Photochemical Reflectance Index [(R₅₃₁-R₅₇₀)/(R₅₃₁+R₅₇₀) where R₅₃₁ is reflectance at 531 nm, PRI] and red-edge (RE) for T. latifolia explained 93% of TA variation (p<0.001) when 0.10 < TP < 0.20 mg-P l^-1.  For the entire range of water quality conditions, an equation containing PRI, RE and the simple ratio R₄₉₃/R₆₇₈ for T. latifolia explained 72% of TA variation (p<0.001).  Hyperspectral reflectance can quantify wetland ammonia concentrations, lending utility to rapid and continuous assessment of emergent wetland water quality. 

Keywords: water quality, remote sensing, hyperspectral radiometry, nitrogen, wetland eutrophication

Can Constructed Wetlands Technology Address Wastewater Treatment for Isolated Communities?  - Canadian and Mexican Initiatives

Mark Williamson and Steve Thompson

Centre for Alternative Wastewater Treatment (CAWT), 

Sir Sandford Fleming College,  Canada

The Centre for Alternative Wastewater Treatment (CAWT) is a Canadian research initiative intended to develop constructed wetlands and other non-traditional technologies as viable alternative treatment options for rural, isolated, northern and developing communities. As one of its first projects, CAWT designed a low-energy, multi-element constructed wetland to treat raw wastewater discharging into the Rio Texcoco in rural central Mexico. A combination of hardpan tepitate soils, lack of electrical power, high COD (2000 mg/l) and sediment loading at this site required innovative system components to effectively treat waste. The system consists of a sediment chamber, terraced rockfalls to reduce solids and increase oxygenation, a stabilization pond, paired horizontal subsurface flow reedbeds, a vertical flow wetland cell dosed with mechanical siphons, a water collection cistern and two vegetated ponds.

By the second year of the project effluent chemical oxygen demand (COD) had been reduced by an average of 85% of influent and total suspended solids (TSS) and nitrate had also been reduced 82% and 96% respectively. In addition, treated wastewater from the system began to be utilized to provide irrigation for the local floriculture trade in Texcoco.

In addition to significantly improved effluent quality, this project also demonstrates  the significance of community valuation and involvement in the establishment and acceptance of alternative treatment technologies. Several significant contributions to the ultimate success of the project, such as the terraced rockfalls and the incorporation of chinampas, or traditional hydroponic gardens modified for the floriculture trade, were a direct result of community initiatives. Long-term management and maintenance of the system lies ultimately in local hands. Overall, the CAWT Rio Texcoco project provides a good case study illustrating how small or isolated communities can better manage their wastewater and leave a smaller footprint on overall water resources.

Keywords: constructed wetland, tepitate, vertical flow, dosing siphon, biofilm, COD, total suspended solids, nitrate, chinampas, floriculture.

Back to Top

Instructions

Please submit an abstract to AEES2003@umail.umd.edu as an MS Word or Wordperfect document by Friday, January 24^th, 2003. Abstracts should be no longer than 250 words and contain the following: Title, author(s) names, key contact information (phone #, e-mail, address, fax). Signify poster or talk. If absolutely necessary, abstracts may be faxed to 1-301-314-9023.

AEES2003 Organizing Committee will review and provide a response via e-mail by Friday February 21^st.

Papers and Posters

Oral presentations are scheduled for 20 minutes (15 minutes presentation plus 5 discussion). Slide projector, overhead projector, computer (PC Windows OS) and video projector will be available.

A poster session is scheduled for Thursday afternoon; however, posters will be on display througout the meeting. Poster size will be 40" x 60", which will be attached to foam core on easels.