John Stansbury

Adaptive photovoltaic system

This paper discussed a new photovoltaic (PV) system topology that uses PV energy in efficient way in order to improve system power output during different operating conditions. The proposed topology provides flexible connection between PV modules to achieve different configurations of PV array. A new switching matrix has been developed to achieve the required configurations. Preliminary simulations provide promising results for an adaptive PV array. Comparison between traditional PV system configurations and adaptive configuration is considered. A significant improvement in power curves is achieved by the proposed topology.

Decision support system for water transfer evaluation

A decision support system (DSS) is developed to help decision makers analyze the economic, social, and ecological ramifications of water transfers. Such a DSS is needed because the U.S. is evolving from a development water economy to a more complex one that emphasizes conservation and reallocation (i.e., transfers). The DSS is composed of three main modules: (1) a conjunctive surface-ground water model, (2) the impact analysis segment which uses a geographical information system that integrates model output with information from the study area to estimate economic, social, and ecological impacts, and (3) a multicriteria decision making algorithm that ranks the transfer schemes based on trade-offs of indicators which are assembled into a hierarchical structure. A case study in which 10 different water transfer alternatives are examined is provided to demonstrate an application of the proposed DSS.

Real Time Power Monitoring & integration with BIM

A Real Time Power Monitoring (RTPM) System is proposed in which end-use detailed energy consumption data is provided for each load level. The data will be integrated with a BIM (Building Information Modeling) Model to create a Realtime on-line electronic BIM Model. This paper describes the RTPM system and the process leading to its creation. The basic components of the proposed system were designed and tested using a prototype board.

Risk-Cost Trade Off Considerations for Contaminated Sediment Disposal

Delays in dredging and inability to dredge the nations harbors, due to the presence of contaminated sediments and the lack of environmentally acceptable disposal sites are interfering with shipping activities and hampering trade growth. The United States Government is committed to provide continuing support to the port industrys goals for enhancing economic growth while protecting, conserving and restoring natural resources within coastal aquatic lands. The governments commitment has resulted in the articulation of a national dredging policy in the Action Plan for Improvement of the Dredging Process in the United States. This national challenge calls for a systematic and consistent decision making approach to dredging and disposal including contaminated sediment management. In building an effective decision mak ing framework for costs, risk reduction and potential beneficial uses of the disposal material must be considered in identifying and evaluating environmentally acceptable and cost-effective disp...

Contributions of Internal and External Fouling to Transmembrane Pressure in MBRs: Experiments and Modeling

AbstractThis paper reports a new approach to understanding membrane fouling in membrane bioreactors (MBR). The foulants were categorized into those inside the membrane (internal fouling) and those on the membrane forming the so-called external fouling layer (external fouling). The volumes of the internal and external foulants were determined with the aid of a confocal laser scanning microscope (CLSM) after staining the foulants. Thus, the porosities of both the membrane and the external fouling layer were calculated, which explained the contributions of internal and external fouling to transmembrane pressure (TMP) from the standpoint of fundamental filtration theory. The categorical method indicates that external fouling may dominate the long-term operation of MBR with the formation of the external fouling layer, whereas internal fouling, in the form of pore constriction, may cause both initial and final TMP jumps under the operating conditions in the current study. In addition, a mathematical model was d...

Graywater reclamation by a shredded tire biofilter and a membrane bioreactor in series

AbstractThe search for sustainable and effective water reclamation technologies has been stimulated by increasingly urgent water scarcity. Graywater (GW) is an excellent potential resource for relieving the water scarcity problem because it has a relatively low pollution level and because it is abundant and accessible. GW makes up approximately 70% of domestic wastewater. A new technology, shredded tire biofilter (STB), combined with a membrane bioreactor (MBR), was demonstrated to be an efficient method for treating GW to a level that satisfies the USEPA’s water reuse guidelines. In the proposed technology, the MBR ensured adequate effluent water quality, and the STB pretreated the GW. The technology may significantly reduce the energy required to treat GW by MBRs alone. It was further observed that increasing hydraulic retention time and decreasing shredded tire particle size enhanced the removal of BOD5 in the STBs. Analysis of biofilms on shredded tire chips showed that microorganisms could attach and...

Risk-Cost Analysis Under Uncertainty of the Disposal of Contaminated Dredged Material

Risk-cost analysis can be used as a management tool to help determine which water resource management alternatives best satisfy both ecological and economic concerns. However, risk and cost assessments are often associated with very large uncertainties stemming from such factors as contaminant transport modelling and loss function assessment. If risk-cost analysis is conducted without considering these uncertainties, inappropriate management policies may result. On the other hand, considering these uncertainties may cause difficulties in decision making if they make management alternatives effectively indistinguishable. Disposal of contaminated dredged material is a water resource problem where both risks and costs are important considerations. Risks from disposal of contaminated dredged material may be reduced by incorporating measures to confine the contaminated dredged material; however, these confinement measures may increase disposal costs significantly.

Economic Input-Output Life Cycle Assessment of Water Reuse Strategies in Residential Buildings

1.0 Introduction The growth of cities is putting great strains on existing freshwater supplies in many areas, including the United States (Kloss, 2008). The United States Green Building Council (USGBC) has stated that buildings consume roughly 39% of all electricity and approximately 10% of all potable water (USGBC, 2008). The growing need for freshwater has lead to an increase in water reuse applications. However, some water reuse strategies actually result in an increase in energy usage and other environmental impacts. The objective of this study is to determine the environmental sustainability of three water reuse designs through economic input-output life cycle assessments (EIO-LCA). The water reuse designs include a simple greywater reuse system for subsurface landscape irrigation; an indoor greywater reuse system for toilet flushing and laundry washing; and a hybrid greywater and rainwater reuse system for landscape irrigation, toilet flushing, and laundry washing.

Feasibility of developing a passive sampler for sampling heavy metals in BMPs for stormwater runoff management

ABSTRACT Structural Best Management Practices (BMPs) have been used for stormwater treatment and management for several decades. How to monitor these BMPs performance reliably and economically is a challenge. This paper reports the feasibility of developing a flow through passive sampler (PS) based on Amberlite IRC748 ion exchange resin operated in kinetic regime for sampling heavy metals in BMPs (infiltration systems) for stormwater treatment and management. Tests were conducted using batch reactors and laboratory-scale BMPs. Batch reactor results indicate that PSs performed desirably with consistent and rapid metal uptake, and thus, the resin-based PS is feasible to be used for stormwater sampling. In lab-scale BMPs tests, the resin PSs were employed for sampling influent and effluent of BMPs loaded with synthetic stormwater for storm durations of 0.5, 3, and 12 hours. The removal efficiency of heavy metals in the BMPs as predicted by PSs was very similar to the actual treatment efficiencies obtained from control BMPs, with errors ranging from –5% to 2%, indicating that the PSs can be used for sampling stormwater and monitoring BMPs. The next step for this sampler will be to develop a method for evaluating the volume of water passing the PS during the sampling period.

Polyurethane foam (PUF) passive samplers for monitoring phenanthrene in stormwater

Pollution from highway stormwater runoff has been an increasing area of concern. Many structural Best Management Practices (BMPs) have been implemented for stormwater treatment and management. One challenge for these BMPs is to sample stormwater and monitor BMP performance. The main objective of this study was to evaluate the feasibility of using polyurethane foam (PUF) passive samplers (PSs) for sampling phenanthrene (PHE) in highway stormwater runoff and BMPs. Tests were conducted using batch reactors, glass-tube columns, and laboratory-scale BMPs (bioretention cells). Results indicate that sorption for PHE by PUF is mainly linearly relative to time, and the high sorption capacity allows the PUF passive sampler to monitor stormwater events for months or years. The PUF passive samplers could be embedded in BMPs for monitoring influent and effluent PHE concentrations. Models developed to link the results of batch and column tests proved to be useful for determining removal or sorption parameters and performance of the PUF-PSs. The predicted removal efficiencies of BMPs were close to the real values obtained from the control columns with errors ranging between -8.46 and 1.52%. This research showed that it is possible to use PUF passive samplers for sampling stormwater and monitoring the performance of stormwater BMPs, which warrants the field-scale feasibility studies in the future.