Dipankar Sen

Dipankar Sen
Virginia Tech · Civil and Environmental Engineering

PhD, Virginia Tech, Department of Civil and Environmental Engineering

About

80
Publications
24,317
Reads
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679
Citations
Additional affiliations
July 2016 - present
Virginia Polytechnic Institute and State University
Position
  • Professor (Associate)
July 2016 - present
Virginia Polytechnic Institute and State University
Position
  • Professor (Associate)
Description
  • Water Reuse, Advanced Treatment, Asset Management, Artificial Intelligence, Sensors and Simulation
September 1998 - June 2000
University of Pennsylvania
Position
  • Business School

Publications

Publications (80)
Article
A new software application, called URUNME, was developed in C#.NET for integrated environmental modeling. URUNME provides functionality for model coupling, data storage, analysis, visualization, scenario management, and decision support systems. A graphical user interface (GUI) based on drag-and-drop flowchart type diagrams allow modelers to set-up...
Article
Full-text available
Optimal operation of water reclamation facilities (WRFs) is critical for an indirect potable reuse (IPR) system, especially when the reclaimed water constitutes a major portion of the safe yield, as in the case of the Occoquan Reservoir located in Northern Virginia. This paper presents how a reservoir model is used for predicting future reservoir c...
Article
Full-text available
An Artificial Intelligence system was developed and implemented for water, wastewater, and reuse plants to improve management of sensors, short and long‐term maintenance plans, asset and investment management plans. It is based on an integrated approach to capture data from different computer systems and files. It adds a layer of intelligence to th...
Article
Full-text available
An Artificial Intelligence (AI) system has been developed and implemented for water, wastewater and reuse plants to improve management of sensors, short and long term maintenance plans, asset and investment management plans. It is based on an integrated approach to capture data from different computer systems and files. It adds a layer of intellige...
Conference Paper
Full-text available
Optimum operation of water reclamation facilities (WRF) is critical for an indirect potable reuse system (IPR), especially when the reclaimed water constitutes a major portion of the safe yield of the augmented reservoir. As population grows and fresh water availability varies, the need for timely and reliable decisions related to plant operations...
Conference Paper
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The methodology of asset management and Triple Bottom Line (TBL) analysis for wastewater plants was enhanced to allow for a comprehensive analysis of wastewater treatment systems that have to meet additional levels of service (LOS) for water supply through the reuse of the treated effluent. In the City of Livermore, CA, the LOS for water reuse beca...
Conference Paper
Full-text available
An intelligent system has been developed and implemented for water, wastewater and reuse plants to improve management of sensors, improve short and long term maintenance plans, asset and investment management plans. It is based on an integrated approach to simulate processes and assets to improve or optimize operations, maintenance and asset manage...
Conference Paper
Full-text available
Data from various parts of California show that without the optimization of assets for a recycled water system, the cost of recycled water production can exceed $1500 per acre foot (1 acre foot equals 0.3 million US gallons, which is equal to 1250 m 3), as compared to $500 per acre foot for raw water that may be purchased and transported from natur...
Conference Paper
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Based on needs identified by utilities and regulators to improve efficiencies, asset utilization and reduce life cycle cost, an intelligent system that incorporates process, maintenance and asset management was developed and implemented at several BNR and ENR plants. After the first two years of operation, plant staff identified additional applicat...
Conference Paper
Full-text available
An intelligent system has been developed and implemented at several BNR and ENR plants. It is based on an integrated approach to simulate processes and assets to improve or optimize operations, maintenance and asset management. It is also being used for Master Planning for Water and Biosolids Reuse. The IViewOps system incorporates an approach wher...
Article
An intelligent system has been developed and implemented at several BNR and ENR plants. It is based on an integrated approach to simulate processes and assets to improve or optimize operations, maintenance and asset management. It is also being used for Master Planning for Water and Biosolids Reuse. The IViewOps system incorporates an approach whe...
Article
Analysis of stream conditions in several urban waterways in Santa Clara County, CA, show gradual but significant changes in their morphology over time. Several streams are showing signs of incision (erosion) of the bed. Typically, this is observed in reaches with moderate slope. These reaches are located between the upland hilly areas and the low l...
Conference Paper
Full-text available
Water Utilities are familiar with managing point assets in treatment plants. In some instances, they have improved asset management systems for constructed linear assets, such as pipelines, tunnels, and canals for water conveyance; roads for transportation; and levees and floodwalls for flood protection. More recently, there has been an interest in...
Conference Paper
Full-text available
Based on needs identified by Utilities and regulators to improve efficiencies, asset utilization and reduce life cycle cost, an intelligent system that incorporates process, maintenance and asset management has been developed and implemented in phases at several BNR and ENR plants. The needs required features that extend beyond process design model...
Conference Paper
Full-text available
Analysis and operating experience with BNR and ENR plants operating with denitrification filters and membranes (MBR plants) show that there may be opportunities to reduce life cycle costs through global optimization. Global optimization optimizes works with DCS and SCADA system not just at the denitrification filter or the MBR but across the entire...
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A data collection and asset management system for linear and spatial assets was developed, tested in the field, and is going through annual improvements to address the challenges in managing linear and spatial assets and conditions. The system has to be applied to natural and constructed assets that are part of the Utility's operation. Additionally...
Article
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This paper discusses the development and application of a whole plant simulation and control system for simultaneous optimization of processes and assets. It overcomes several limitations in Distributed Control Systems (DCS) and SCADA systems, as implemented today in ENR plants for local optimization of secondary treatment, tertiary treatment and s...
Article
Full-text available
A data collection and asset management system was developed to address the challenges in managing linear and spatial assets and conditions on watersheds and waterways. The system can be applied at the enterprise level in a Utility or Agency whose assets span a large geographic area, are constructed over time, and have to satisfy multiple objectives...
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This paper discusses the development and application of Asset Management Intelligent Decision Support Tool (AMIDST) to improve the management of plants, distribution, collection and water reuse systems. The tool analyzes the combinations of operating set-points and assets. It is integrated with the plant systems such that it captures the current da...
Article
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A real time whole plant simulator for process control and optimization (Aquifas+ , Aquifas Plus) was developed using an enhanced version of IWA ASM2d model for mixed liquor and biofilm, together with advanced mathematical algorithms for achieving higher speed and accuracy required for real time operations control and optimization as compared to pla...
Article
The challenges of simultaneous optimization of a whole wastewater treatment plant for permit compliance, energy, chemical use and GHG emissions across primary, secondary and tertiary systems, together with solids handling, are significant. A real time whole plant simulator for process control and optimization (Aquifas+) has been developed with a co...
Article
Full-text available
Biological denitrification is a process where nitrate is reduced to nitrogen gas in a step-wise manner by electron donors (usually methanol, acetic acid, or ethanol) in the absence of oxygen. A fixed-film denitrification process is basically a biofilm process, which fundamentally consists of two simultaneous steps, substrate diffusion and biologica...
Article
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Asset management has traditionally been applied at Water and Power Utilities as discrete stand alone systems for work order and inventory management. Repairs and replacement are conducted on a time based cycle. Improvements in computational and data management techniques show that this can be expanded to bring about substantial improvements in the...
Article
A comparative study of two adjacent stream channels in the Santa Clara Valley region of California provided an opportunity to study the relative effects of multi-faceted watershed-urbanization impacts on channel evolution and stability. Berryessa Creek (15.5 km2) and Upper Penitencia Creek (61.3 km2) have similar intrinsic watershed characteristics...
Article
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Mathematical models are critical to modern environmental biotechnology-both in research and in the engineering practice. Wastewater treatment plant (WWTP) simulators are used by consulting engineers and WWTP operators when planning, designing, optimizing, and evaluating the unit processes that comprise municipal and industrial WWTPs. Many WWTP simu...
Article
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A MBR model was developed to include biofilm and activated sludge components modeled along the guidelines established by the IWA Task Groups. The biofilm components allow the user to specify the biofilm specific surface area for media (m2 of media surface/m3 of tank volume with media) in the anoxic and aerobic cells upstream of the MBR cell. Within...
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Evaluation of full scale plants show that both fixed bed media and moving bed media can work in IFAS systems, provided that the design and operating conditions account for the differences between the two types of media. With respect to MLSS, the operating conditions of fixed bed and moving bed media systems showed that while fixed bed systems tend...
Article
Full-text available
Research was undertaken to determine the potential for changes in GHG emissions based on the magnitude of aeration, as enhanced by the need for mixing and shearing biofilm (to manage the biofilm thickness), the type of media (fixed bed versus moving bed), and the location of media in IFAS systems. The information was used to verify the biofilm and...
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Practicing wastewater process engineers use mathematical models when planning, designing, optimizing, evaluating, and performing problem solving work related to proposed or existing municipal and industrial WWTPs. This paper presents the result of research on the extension of ASM2d to model GHG emission using Aquifas+ WWTP simulator. A significant...
Article
With stringent effluent standards in the Chesapeake Bay watershed and elsewhere, wastewater treatment is becoming a more complex and precise process. This has created a need for an accurate whole plant process simulation software tool that can be used by both wastewater treatment designers and operators. It was reco gnized that modeling software ca...
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Full-text available
The principles of Asset Management, have traditionally been applied to Water, wastewater, and transportation Utilities and focused on constructed physical assets. Yet, these principles are applicable to all management functions within a utility or organization. In our case, the principles of asset management have been applied to waterways where the...
Article
Full-text available
One of the difficulties in waterways and watershed asset management is the geographic distribution of assets. Such assets include reaches of creeks, both natural and constructed; storm drains, levees and pipelines that are linear in nature (though not necessarily straight lines in the case of creeks); and fixtures that are at specific locations wit...
Article
Full-text available
There are two basic types of denitrification filters being used in the Chesapeake Bay region to meet enhanced nutrient removal (ENR) level effluent requirements: continuously backwashing upflow sand filters (herein called “continuously backwashing denitrification filters”) (CBDF) and intermittent backwashing downflow sand filters (herein called “do...
Article
Full-text available
All major wastewater treatment facilities in the Chesapeake Bay watershed will soon be required to implement enhanced nutrient removal (ENR). The permit requirements for ENR vary from state to state; for example, facilities in Maryland are required to achieve an annual average effluent quality of < 4 mg/L TN and < 0.3 mg/L TP. The requirement to op...
Article
Full-text available
Research was undertaken to develop the IWA ASM2d based Aquifas process model for all activated sludge and biofilm systems. The model operates for steady state and dynamic simulation on two platforms: Excel-Visual Basic and Microsoft.NET platforms. The latter provides a complete graphical user interface for operators to use within a plant. The model...
Article
Full-text available
The Membrane Bioreactor (MBR) design was adapted to the conditions in emerging economies in Mexico, Latin America and elsewhere. A simulation model (Aquifas) was customized to the conditions to allow for a faster and reliable design that is also optimized to achieve lower and flexible footprint to ensure that plant fits within the area available. T...
Article
Full-text available
One of the difficulties in waterways and watershed asset management is the geographic distribution of assets. Such assets include reaches of creeks, both natural and constructed; storm drains, levees and pipelines that are linear in nature (though not necessarily straight lines in the case of creeks); and fixtures that are at specific locations wit...
Article
Full-text available
In many areas of the country where receiving waters have been identified as nutrient impaired, state regulatory agencies are tightening requirements for effluent nitrogen and phosphorus in wastewater treatment facility discharges. For facilities which are already designed for nitrification, or which can be retrofitted to achieve full nitrification,...
Conference Paper
Full-text available
An Asset Management program can be used to monitor the condition of each asset with respect to its level of service, manage the preventive and corrective maintenance, and manage the risks. For waterways and watersheds, it is necessary to involve a multidisciplinary team of biologists, engineers, scientists, operations specialists and management con...
Article
Full-text available
Research was undertaken to develop a diffusional model of the biofilm that can be applied in lieu of a semi-empirical model to upgrade an activated sludge system to an integrated fixed-film activated sludge (IFAS) or moving-bed biofilm reactor (MBBR) system. The model has been developed to operate with up to 12 cells (reactors) in series, with biof...
Article
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Research was undertaken to analyze and verify a model that can be applied to activated sludge, integrated fixed-film activated sludge (IFAS), and moving-bed biofilm reactor (MBBR) systems. The model embeds a biofilm model into a multicell activated sludge model. The advantage of such a model is that it eliminates the need to run separate computatio...
Article
Full-text available
Research was undertaken to develop a model for activated sludge, integrated fixed‐film activated sludge (IFAS), and moving‐bed biofilm reactor (MBBR) systems. The model can operate with up to 12 cells (reactors) in series, with biofilm media incorporated to one or more cells, except the anaerobic cells. The process configuration can be any combinat...
Article
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Research was undertaken to develop an open source model that can be applied to activated sludge systems operated as Membrane Bioreactors (MBRs). The model has been developed to operate with up to 12 cells (reactors) in series. The values of the kinetic parameters for the model were developed from pilot scale activated sludge systems. The process co...
Article
Full-text available
Research was undertaken to develop an open source model that can be applied to activated sludge systems operated as Membrane Bioreactors (MBRs), in addition to other compact solutions such as Integrated Fixed Film Activated Sludge (IFAS) and Moving Bed Biofilm Reactors (MBBRs). The model has been developed to operate with up to 12 cells (reactors)...
Article
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Hollow fiber membrane bioreactors (MBRs) were evaluated in full scale to study methods of reducing their aeration and air scour energy requirements. The changes were modeled to determine methods to optimize the aeration and air scour energy consumption and compare the total to the aeration energy requirements of conventional activated sludge (CAS),...
Article
Full-text available
The Water Environment Federation (WEF) convened a task force to assemble and analyze case studies documenting how techniques such as watershed-based permitting, pollutant trading, and novel wet weather strategies have been used successfully to reduce or avoid the expense of current and future of facility upgrades. Interviews of the case study utili...
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Full-text available
Stream rehabilitation methods developed in rural watersheds were modified and applied to moderate and highly urban watersheds. Urbanization increases the impervious area in the watershed, constrains the stream corridor width, and in some instances, reroutes the channel in a manner that reduces its length. The method developed integrates the fundame...
Article
Research on full scale Integrated Fixed Film Activated Sludge (IFAS) and Mobile Bed Biofilm Reactor (MBBR) systems showed that problems developed with excessive biofilm thickness when the mixing and roll patterns decreased. Evaluated media included fixed bed cord media, moving bed sponge media and moving bed plastic media. Three strategies are reco...
Article
Full-text available
Research was undertaken to calibrate and verify the Aquifas semi-empirical and biofilm 1D models against a full scale Integrated Fixed-Film Activated Sludge (IFAS) system. The model was then used to evaluate and identify alternatives to upgrade the performance of tertiary IFAS system and Moving (mobile) Bed Biofilm Reactor (MBBR) systems that could...