September 19, 2017

Geosyntec Participation at WEFTEC 2017

As in previous years, Geosyntec staff will make a significant technical contribution to WEFTEC 2017 in Chicago, Illinois on September 30 - October 4, 2017.  

Geosyntec professionals will conduct two workshops, lead a special seminar, moderate a technical session, and deliver 12 presentations.

WEFTEC is the largest conference in North America to offer water quality professionals from around the world with water quality education and training. Also recognized as the largest annual water quality exhibition in the world, the show floor provides access to advanced technologies, serves as a forum for domestic and international business networking; and promotes peer-to-peer networking among registrants.

WEFTEC is sponsored by The Water Environment Federation (WEF), a not-for-profit technical and educational organization of 33,000 individual members and 75 affiliated Member Associations representing water quality professionals around the world. Since 1928, WEF and its members have protected public health and the environment. As a global water sector leader, their mission is to connect water professionals; enrich the expertise of water professionals; increase the awareness of the impact and value of water; and provide a platform for water sector innovation.

Geosyntec Participation

Geosyntec Members Presenting Workshops

WEF/WE&RF Integrated Planning: A Solution for Your Utility?
    • Adrienne Nemura and Elizabeth Toot-Levy
    • Saturday, September 30 | 8:30 am – 5:00 pm
    • W13. SA, Room S502a
Water Reuse in the Food and Beverage Industry
    • Joe Cleary
    • Sunday, October 1 | 8:30 am – 5:00 pm
    • W.16 SA, Room S503a

Geosyntec Members Presenting Technical Papers/Presentations

#1856. Coal-Fired Steam Electric Power Plant Water Balance Study and Development of Computational Model for Compliance with USEPA Effluent Limitation Guidelines
    • Mike Hickey as Primary Author
    • Jared Champion, Hari Parthasarathy, Allison Kreinberg, and Bruce Sass as Co-Authors
    • Tuesday, October 3 | 9:30 am
    • 303. TU, Room S405a
    • Abstract

The USEPA promulgated the new Effluent Limitations Guidelines (ELG) rule (Federal Register Vol. 80, No. 2012, 3 November 2015) for coal-fired steam electric power plants in November 2015. The new USEPA ELGs became effective in January 2016 and requires the elimination of discharges of fly ash transport water and bottom ash transport water, as well as stringent limits on discharge from flue gas desulfurization (FGD) wastewater. Compliance under the new USEPA ELGs is required by 2023. In order to meet the USEPA ELGs, a coal power plant operated by a confidential client is undergoing a water balance and wastewater characterization study. Wastewater sources considered in the study include cooling tower blowdown, bottom ash and pyrite sluices, coal pile runoff, fly ash transfer building sumps, and low volume wastewaters. These wastewater sources currently combine in an ash pond where wastewater is treated by sedimentation, flocculation, and neutralization. Excess treated wastewater that is not recirculated to the plant is discharged from a reclaim pond at each plant under a National Pollutant Discharge Elimination System (NPDES) permit to the Ohio River. The primary objective of the water balance study is to identify wastewater sources that may be contributing to final effluent discharges of inorganic constituents that may exceed future federal effluent limits. The water balance and waste characterization study has consisted of three parts. First, a detailed water balance diagram was developed showing the flow paths of all incoming water sources (city water, river water, rain water, etc.) and all outgoing wastewater sources (i.e., sump pumps, storm stations, process flows, and other waste streams). Engineering drawings of wastewater sources were reviewed, operational information was discussed with plant personnel, and a plant walk down was conducted to confirm findings. Second, the flow rates and mass loadings for each wastewater source were measured or estimated. Some flows are episodic (weather, seasonal, or dependent on electric grid demand), and some flows have continuous output (e.g., cooling tower blowdown and bottom ash transport water). The chemical composition of all incoming and outgoing flows was determined by sampling and laboratory analysis. Four sampling events were scheduled; during each event, all sampling and flow monitoring was performed in a single day for all locations. All four sampling events were completed over a 6-month period. Third, a database of flow rates and chemical compositions was developed in conjunction with a computational water balance model. Analytical and field data were validated and uploaded into a Microsoft Access database that exported flow and concentration data to an electronic dynamic link library for data management. The geochemistry of the wastewater sources mixing in the ash ponds and precipitation of particulates was modeled using a GoldSim water balance model linked to a PHREEQC geochemical equilibrium model. A proofing/validation exercise was performed on the computational water balance model using statistical computation to compare the observed values to the modeled values for the four sampling events. The model allows for computational evaluation of the benefits from adding treatment or eliminating individual wastewater sources under different operational scenarios. The computational water balance model will be used by the client during future engineering design to meet the USEPA ELGs. An overview of work involved with developing the water balance diagram, measuring and estimating flow rates and chemical compositions, and development of the computational water balance model will be presented. The results of the computational model under different operational scenarios (e.g., elimination of bottom ash transport water, pyrites transport water, and fly ash wastewater from the ash pond; pretreatment of high-strength wastewater streams) will be presented.

323 Area 51 and Other Challenging Settings for Stormwater Management
    • Scott Struck as Moderator (Technical Session)
    • Tuesday, October 3 | 10:30 am – 12:00 pm
    • 323. WE, Room S503b
    • Description

Stormwater runoff from industrial land uses and other contaminated sites present special design and maintenance challenges. This session features a case study of stormwater management implementation at the Los Alamos National Laboratory in New Mexico, where legacy radiation and contamination must be managed along with security concerns; results and data for industrial stormwater treatment and control measures for a City-owned industrial site in Columbia, Missouri, where an aquatic life TMDL required significant measures to reduce metals, toxics and nutrients; and development of a performance model for industrial stormwater filter media. This session will be of special interest to designers, engineers, and regulators concerned with effective approaches to pollutant reduction at challenging industrial and non-traditional sites.

#1818. Monitoring Urban/Industrial Stormwater Green Infrastructure BMP Performance for Runoff Quality and Quantity
    • Nick Muenks (Adrienne Nemura will be presenting on his behalf) as Primary Author
    • Marc Leisenring, Mark Willobee, and Nicki Fuemmeler (Boone County Missouri) as Co-Authors
    • Tuesday, October 3 | 11:00 am
    • 323. TU, Room S503b
    • Abstract

Background In 2011, EPA approved a total maximum daily load (TMDL) for aquatic life impairment of Hinkson Creek in Boone County, Missouri due to unknown sources. As a result, the municipal separate storm sewer system (MS4) co-permittees - Boone County, City of Columbia, and the University of Missouri needed to significantly reduce the impact of stormwater runoff. In response to the TMDL, Boone County's Resource Management Division applied for and received a Section 319 grant (grant) through the Missouri Department of Natural Resources (MDNR) to implement and evaluate stormwater reduction measures within the greater Hinkson Creek watershed. Evaluating the effectiveness of stormwater Best Management Practices (BMPs) was a key component of the grant. A step pool conveyance and a bioretention cell were implemented around an urban-industrial site operated by the City of Columbia and monitored for a period of two years. The monitoring data were used to evaluate BMP performance by characterizing common urban pollutant reductions and quantifying runoff volume reductions. Pollutants included phosphorus, nitrogen, solids, metals (copper, lead, and zinc), and chemical oxygen demand. The information gathered are further being used to inform watershed planning initiatives in the greater Hinkson Creek watershed and the county, populating BMP performance databases (local and the International Stormwater BMP Database, 2016), and supporting outreach and education activities.

Project Objectives Improved technical knowledge regarding the efficacy of stormwater best management practices (BMPs) and low impact development (LID) was needed to help achieve the goals of the Hinkson Creek Total Maximum Daily Load (TMDL) and local stormwater ordinances. The performance of current BMP practices has not been field validated with respect to runoff volume reduction, peak flow reduction, and runoff water quality improvement for this area. Missouri has distinct soil and climate characteristics, so performance data gathered from other regions of the U.S. may not be representative of this area with respect to runoff characteristics and the associated BMP sizes necessary to provide an expected level of stormwater control. The objective of the grant was to implement selected BMPs, and study their performance with respect to water quality benefits, pollutant load reductions, and hydrologic response. This project had two distinct monitoring objectives based on the selected types of BMPs:

  • Characterize the reduction of common urban stormwater pollutants through selected BMPs, and
  • Quantify runoff volume reduction from installed retrofit BMPs.

STUDY AREA For this project, a BMP site was investigated within the Bear Creek (Grissum Building) watershed, adjacent to the Hinkson Creek watershed (Figure 1). The Grissum Building (Figure 2) property, owned and operated by the City of Columbia, is an industrial type operations facility that includes vehicle maintenance, vehicle and material storage, and public works operations activities. At approximately 10 acres in size, this site is located within city limits and the Bear Creek watershed. Originally the site included no BMPs to capture and treat stormwater runoff. Two BMPs were designed and implemented for this monitoring project; a bioretention cell and a step pool storm conveyance treatment train (step pool).

Data Collection Monitoring occurred at the Grissum Building BMPs from September 28, 2012 until January 6, 2015. To quantify the effectiveness of the bioretention cell and the step pool conveyance BMPs at the Grissum Building, Hach Sigma 900 Max automatic samplers measured and collected runoff entering and leaving each BMP on a storm event basis. A storm event is defined as any 24 hour event with more than 0.2 inches of total precipitation resulting in flow through the BMPs. To be valid for sampling for the step pool conveyance, the storm had to have a minimum antecedent dry period of six hours. A valid sampling event from the bioretention cell required it to be dry (no ponded water) prior to a qualifying storm event.

Results Grissum Building step pool was monitored during twenty (20) precipitation events from the fall of 2012 to winter of 2014. Early events, prior to good establishment of the flora community, indicated little treatment was occurring through the step pool and only periodic removal of solids occurred. Following establishment of the plant community the step pool performance significantly increased with consistent reductions in nearly all pollutants monitored. This suggests that step pool BMP may not effectively reduce pollutants in the early stages of its implementation. Monitoring results obtained for Total Phosphorous, before and after the establishment of vegetation along the step pool system is shown in Figure 3. The Grissum Building bioretention cell was monitored during eleven (11) events from the winter of 2012 to January 2015. Results from the analysis of paired inlet and outlet samples indicate the bioretention cell can efficiently remove common stormwater pollutants found at industrial sites. Monitoring results obtained for Total Nitrogen is shown in Figure 4. Also, bioretention inlet and outlet flow monitoring data indicate a significant reduction in peak storm flows. There are however some factors to be considered for future implementation such as design, pre-treatment, and maintenance requirements. Overall the project was successful in achieving the goals set forth. The information generated by this extensive effort was entered into the International BMP Database (BMP Database, 2014) and will provide valuable information for BMP performance based on local conditions to engineers, developers, City construction and maintenance staff, and state and local stormwater managers.

#2298. Development and Implementation of the City of Calgary LID Monitoring Program
    • Scott Struck as Primary Author
    • Myles Gray, Marc Leisenring, and Nick Muenks as Co-Authors
    • Tuesday, October 3 | 1:30 pm
    • 414. TU, Room S503b
    • Abstract

In an effort to provide sustainable stormwater solutions, the City of Calgary (City) is implementing Low Impact Development (LID) practices or as locally termed, Source Control Practices (SCP) projects as part of its commitment and regulatory goals to protect the water quality in its watersheds. The purpose of SCPs is to capture and treat stormwater runoff at or close to the source with objectives of mimicking pre-development hydrology and improving water quality characteristics of site discharges. Implementation is being done through pilot projects, capital improvement projects, and subdivision projects. To document and understand the associated function, performance, and additional benefits for the local climate, the City has invested in a monitoring program to assess these projects. The monitoring program evaluates several types of SCP pilot projects implemented within the City, including bioretention, soil cells, permeable pavement, green roofs, absorbent landscapes and infiltration chamber technologies. Development of a general SCP monitoring guidance for many City implemented SCPs was the first phase of the project followed by site specific monitoring plans to answer most needed design and performance questions. The implementation of the monitoring plan began in 2016 and will continue into spring of 2017. The presentation will provide an overview of the development of the monitoring program, to include monitoring objective prioritization, implementation, monitoring results, and lessons learned from implementing the individual site plans.

Objectives Since 2010, several SCP pilot projects have been installed by the City in established areas, and others are currently being planned or designed. The need for a SCP monitoring program has been identified as a critical need to support the City's Stormwater Management Strategy. The main objectives of the monitoring program are to:

  • Demonstrate pilot scale technology and gain a better understanding of SCP effectiveness to meet stormwater management goals. This understanding will support adoption of SCPs on a city-wide scale;
  • Collect monitoring data and analyze SCP technology performance. Subsequent analysis will be undertaken by the City to validate SCP performance analyses and technical specifications;
  • Provide high level recommendations on system improvement and maintenance requirements at the SCP pilot project sites based on visual observations and monitoring data; and
  • Align the monitoring program with the City regulatory stormwater management requirements and stormwater system monitoring to assess regulatory compliance. The information gathered as part of the monitoring program will be used to:
  • Validate design information contained in the City's Low Impact Development (LID) technical design guidance manuals (modules) to ensure technical analysis techniques and specifications are appropriate, sound and feasible;
  • Use monitoring information to support modeling input information and to optimize parameter selection for numerical modeling tools;
  • Validate modeling tools used by the City; and
  • Create a City database of water quality and quantity data, trends and observations associated with pilot projects to improve long term understanding and performance.

Development of the Monitoring Program One of the overall goals of any SCP monitoring program is to understand the performance of individual SCPs and combinations of SCPs on stormwater quantity and quality. This information can then be used to inform local or watershed-scale stormwater management planning modeling, prioritization and selection of SCP types, SCP design and construction optimization, and SCP operation and maintenance requirements. However, with limited budgets not all questions can be answered. The City's SCP monitoring goals and priorities were summarized based on the results of two workshops with key City personnel (including managers, monitoring teams and consultants. Following objectives identification and prioritization, monitoring of existing SCPs and planning for monitoring future SCPs can be done to produce information that answers the critical and prioritized monitoring questions. FINDINGS Two sites were selected in the 2016 year based on the highest priority monitoring needs and completed projects, selecting the most suitable monitoring sites based on available budgets. The Water Centre Bioretention Area and the Prairie or Absorbent Landscape Pilot SCPs were selected for monitoring in 2016. Initial findings are reported for the Bioretention area. The presentation will provide findings for both sites. Water Center Bioretention The Water Centre bioretention facility, installed in the fall of 2015, was chosen as a critical monitoring site as it has the most controlled environment to measure the full water balance, including the installation of a liner under the facility. In addition, it had been designed and installed with flow and water quality monitoring goals, including inlet and outlet flume for measuring flows and several moisture sensors. A detailed monitoring plan was developed for the site. Inflow and outflow measurements including primary and secondary flow instruments at the inlet and outlet were installed. Monitoring instrumentation provided flow redundancy and allows a greater resolution and accuracy of the flow measurements. Several issues were encountered following contractor install of planned instrumentation. Replacement of the outlet flume was required due to the following issues:

  • The flume was not level on both the longitudinal and lateral planes resulting in an underestimation of the flows.
  • The flume overtopped during a major storm event by potentially four times the rated capacity.

Prior to corrections, recorded data was processed based on several correction factors to obtain the "best estimate" of flow data. The preliminary results achieved by the bioretention area indicate that pollutant load reductions are estimated to be 97% for TSS, 66% for BOD and 54% for phosphorus. Ortho Phosphorus did increase by a significant percentage, indicating leaching of the growing media. The concentrations are fairly low but not insignificant. This is typically of new bioretention areas, which usually require some time to mature following their installation.

Singificance Data from the two pilot sites monitored provide a series of lessons learned that can be applied to design, modeling, and guidance for contractor implementation. Included in the information learned is the importance of as-built drawings, understanding of the critical events for monitoring, as well as many construction and implementation communication gaps that result in lost information and the need for costly retrofits.

Applying Integrated Planning Framework to Water Quality Compliance: Users Guide for Developing an Alternative Analysis and Integrated Water Plan
    • Adrienne Nemura as Primary Author
    • Elizabeth Toot-Levy, Jeff Rexhausen (Economics Center at University of Cincinnati), Patricia McGovern (McGovern Mcdonald Engineers), and Fred Andes (Barnes & Thornburg) as Co-Authors
    • Tuesday, October 3 | 2:00 pm
    • 422. TU, Room S504a
    • Abstract

U.S. Environmental Protection Agency (EPA) established the Integrated Planning Framework in June of 2012 as a response to the economic and environmental consequences that have become common place for municipalities resulting from regulatory inflexibility related to Clean Water Act compliance. The Integrated Planning Framework specifically arose out of discussions regarding sewer overflow enforcement actions. It is, however, applicable to other compliance issues associated with National Pollutant Discharge Elimination System (NPDES) permits for municipal wastewater and stormwater discharges, implementation plans for total maximum daily loads (TMDLs), and other Clean Water Act compliance challenges. Recently completed research for the Water Environment & Reuse Foundation (WE&RF), which consisted of a community insight survey and case studies, was combined with best professional judgment of the research team and the team's reviewers to produce a Users' Guide. The purpose of the Users' Guide (which was still under development at time of submittal) is to help municipalities learn about integrated planning and, if applicable, assemble the appropriate information to begin the integrated planning process. The Users' Guide provides a considerations tool (to determine if integrated planning may or may not be a good fit for a community or whether more information is needed), resource pages for each of the six elements that EPA expects to see in an integrated plan, and appendices that provide advice and discuss drivers, obstacles to integrated planning, and secondary benefits.

#1696. Evaluation of Biofiltration Media for Optimum Stormwater Treatment Under Controlled Outflow Conditions
    • Jessie Fears (Eric Strecker will be presenting on her behalf) as Primary Author
    • Duane Graves, Linxi Chen, Aaron Poresky, and Austin Orr as Co-Authors
    • #1696. Evaluation of Biofiltration Media for Optimum Stormwater Treatment Under Controlled Outflow Conditions
    • Tuesday, October 3 | 2:30pm
    • 414. TU, Room S503b
    • Abstract

Introduction Biofiltration (i.e., bioretention with underdrains) has emerged as a preferred stormwater treatment option in many MS4 permits and has been demonstrated to meet many stormwater management goals. Outlet control and internal water storage configurations have the potential to improve pollutant retention and extend media life and resiliency of biofiltration systems. However, key questions remain about optimal media blends and outlet-control configuration to balance cost and performance, target specific pollutants, support robust vegetation, and extend maintenance/replacement cycles. Geosyntec conducted a column study to develop and evaluate candidate media blends and assess the impact of careful hydraulic control on pollutant removal performance for a major land development project which is required to meet strict NPDES requirements that include outfall monitoring. The study included: (1) Identification, testing, and evaluation of individual media components including both on-site and off-site sand, organic nutrient sources such as coco coir pith, peat and compost, and soil additives such as biochar, granular activated carbon and zeolite. Each component was compared based upon lab permeability, particle size distributions, cation exchange capacity, extractable nutrient and metals content, fertility, cost, and availability at-scale. (2) Formulation of candidate media blends and analysis of similar parameters listed above. (3) Execution of column tests using real stormwater runoff, including probe measurements and laboratory analyses. (4) Selection of preferred media blends and development of construction specifications (ongoing). Beyond the specific project goals, these results are expected to provide valuable information for developing design specifications for biofiltration media in the future, particularly in areas where bacteria and nutrient removal are important for meeting effluent standards and protecting receiving water bodies.

Approach For biofiltration media testing, Geosyntec designed a column apparatus to (i) distribute stormwater evenly across multiple columns each loaded with unique candidate media blends, (ii) maintain constant hydraulic head, (iii) operate at a controlled filtration rate and (iv) maintain a saturation zone in each column. The components of the biofiltration media were selected based on previous chemical and hydraulic testing and included combinations of two sands, coconut coir peat, activated carbon coconut shell, compost, peat, biochar, and zeolite (Table 1). Estimated cost of raw materials for each media blend (not including labor for mixing and packing) ranged from $30 per cubic yard (CY) to $117 per CY. The columns were initially flushed with tapwater over a 32-hour period to condition the media. Three separate batches (1,000 gallons each) of stormwater were collected from Third Creek in Knoxville, Tennessee within 24 hours of storm events that occurred in July and August of 2015. Three additional batches (1,000 gallons each) were collected directly from a storm drain in Knoxville, Tennesee in December 2015, January 2016 and May 2016. Cumulative rainfall depth at the time of stormwater collection ranged from 1.25 to 2 inches. The stormwater was amended according to the amounts listed in Table 2 to represent expected stormwater quality of the land development project site. The amended stormwater was pumped from the holding tanks to an inflow manifold that delivered continuosly mixed flow to each column. Process measurements (turbidity, electrical conductivity, and pH) were taken at hour 1, 5, 9, 11.5, and 31 during each batch. Water quality grab samples were collected from each column at equal time intervals over a 4-day period. Composite samples were analyzed for E. coli, nutrients (total kjeldahl nitrogen [TKN], ammoniacal nitrogen [NH4-N], nitrate-nitrite nitrogen [NO2,3-N], total phosphorus [TP]), total and dissolved metals (aluminum [Al], copper [Cu], iron [Fe], lead [Pb], and zinc [Zn]), total suspended solids (TSS), and total organic carbon (TOC).

Results and Discussion The five media mixes selected for testing provided a range of materials and unit costs for comparison of water quality performance across mixes. All media blends performed well for TSS removal as expected. However, limitations in TSS delivery from the stormwater tanks to the inflow manifold prevented columns from reaching maximum TSS loads (i.e. clogging conditions). Export of phosphorus and dissolved solids were observed for blends containing compost, but nutrient export was not observed for blends containing peat and coco coir. Overall, the most expensive media mix did not provide significant advantages over the other mixes. Similar metals removal was observed across all mixes. As expected, the control column containing only sand and gravel did not export TOC during the study. Due to short holding time, E. coli grab samples were collected twice per batch; therefore, sample size was too small to evaluate trends in bacteria removal. However, observed E. coli removal was generally strong with 80% to 90+% removal for each column. Physical filtration was likely a dominant process in bacteria removal. From a hydraulic standpoint, effluent flow rate was fairly consistent over time for all columns. Clogging due to minor sediment accumulation in feeder lines and/or air bubbles likely contributed to observations of reduced flow rates from some columns. The choking layer (6 in. washed pea gravel and 4 in. washed sand) and outlet flow control contributed to a reduction in turbidity for all columns. Turbidity control was fairly consistent over time with effluent typically 35 NTU or less.

Significance of Findings Significant insights were gained from each phase of this project which are believed to be transferrable to other regions. For example, this research provided information on the type of component tests that translate most reliably to actual column performance. Additionally, this research is among the first to evaluate the use of outlet control (i.e., hydraulic restriction) coupled with higher permeability media to improve contact time and reduce media washout. Bench-scale evaluation of media performance and outlet-control configurations provided important information supporting the final system design prior to large-scale placement of the media. Innovative testing mechanisms, such as those described here, have the potential to provide long-term cost savings and contribute to overall system resiliency.

#2032. Stream Restoration as a BMP: Development of a National Performance Database and Crediting Guidance
    • Marc Leisenring as Primary Author
    • Eric Strecker, Jane Clary (Wright Water Engineers), Brian Bledsoe (University of Georgia), Jonathan Jones (Wright Water Engineers), and Rod Lammers (Colorado State University) as Co-Authors
    • Tuesday, October 3 | 2:30 pm
    • 417. TU, Room S404a
    • Abstract

Introduction Stream restoration provides a multitude of benefits to ecosystems and communities in both urban and rural areas. Stream restoration projects may also provide pollutant trading, crediting, and mitigation opportunities. For example, stream restoration could be a cost-effective element of complying with water quality regulatory programs such as total maximum daily loads (TMDLs) or as part of overall watershed planning efforts to address multiple water quality and quantity issues. During 2016, the Water Environment and Reuse Foundation (WE&RF) sponsored two coordinated projects to advance the state of the practice regarding evaluating and quantifying the water quality benefits of stream restoration practices. The first project focused on development of a national Stream Restoration Database (SRDB) and was cosponsored by Urban Drainage and Flood Control District in Denver, CO. The second project focused on the development of Crediting Guidance for a subset of stream restoration practices. This paper provides discussion, findings, and research recommendations from both projects, which were finalized in late 2016.

Stream Restoration Database The new SRDB is part of a 20-year effort known as the International Stormwater Best Management Practice (BMP) Database (www.bmpdatabase.org), which documents the observed performance of urban stormwater BMPs based upon field monitoring studies. The SRDB module can be used as a tool to help support stream restoration water quality trading/crediting programs and other performance evaluations by providing guidance on project characteristics that should be reported with stream restoration projects, providing a project information storage tool for crediting programs, and eventually serving as a resource to support credit quantification with reasonable, geographically appropriate input values for crediting equations. Ultimately, the SRDB is envisioned as a supporting tool to improve stream restoration designs and/or better target practices to achieve restoration and water quality improvement goals. In addition to completion of data entry spreadsheets and a user's guide to support population of the database, a summary report was completed for the first release of the database in October 2016. The report also integrates findings from an extensive literature review completed as an initial task supporting the project and from the concurrently completed WE&RF-sponsored report Stream Restoration as a BMP: Crediting Guidance. During 2016, an SRDB summary report was completed that provides an overview of stream restoration practices, introduces the SRDB structure and reporting parameters, provides guidance on performance evaluation approaches for stream restoration studies, provides summaries of stream restoration performance studies based on the first release of the SRDB, and identifies research needs.

Crediting Guidance The Stream Restoration Crediting Guidance provides a general technical framework for quantifying the potential water quality benefits of a specific suite of stream restoration practices, focusing on sediment, phosphorus, and nitrogen. However, the concepts could potentially be extended to other pollutants if supported by future research and data. The four practices addressed in the guidance include stream stabilization, riparian buffers, in-stream enhancement via increased hyporheic exchange, and floodplain reconnection. The general technical considerations and challenges for developing stream restoration credits are discussed, along with guidance for credit development. Guidance for assigning credits for each of the four stream restoration practice groups includes background information, project information/data requirements, regional geomorphic considerations, longevity and response time, uncertainty and simplifying assumptions, and recommended crediting approaches. Concepts such as applicable credit area, safety factors (i.e., credit multipliers), credit life, and tracking and accounting are also discussed. However, this Guidance only provides a framework to support the development of crediting programs; therefore, many specifics, including trading ratios, project eligibility, and watershed specific considerations are not prescribed and are instead left for individual programs to assess and finalize on their own. This Guidance also provides information related to verification and monitoring of stream restoration projects. Many reputable guidance documents for monitoring streams pre- and post-restoration have been developed in various parts of the country. Several general approaches can be used to quantify and/or verify the benefits of stream restoration projects including direct monitoring of water quality and stream geomorphology, functional assessment, modeling, and/or some combination of these approaches. Each of the verification approaches has strengths and weaknesses. Although the Guidance focuses primarily on the water quality characterization aspect, it discusses how the most useful approach is to incorporate aspects of each, depending on the project type and the goals of the monitoring. Information in this Guidance is appropriate for supporting the initial technical basis of water quality crediting programs for stream stabilization, riparian buffers, in-stream enhancement and floodplain reconnection as part of water quality trading and/or crediting programs.

Conclusion The SRDB provides a framework for consistently monitoring and reporting information useful for evaluating the water quality related benefits of various stream restoration practices. To date, water quality parameters reported in stream restoration studies with the most monitoring data are sediment and nutrients. Stream restoration practices with the most well developed data sets, although still limited, included bed and bank stabilization, riparian buffers, in-stream enhancement, and floodplain reconnection. The empirical evidence for stream restoration as a water quality BMP is improving, but additional research is needed, especially for regions and stream types that are absent from or under-represented in the literature. Similarly, some practices have a stronger empirical basis than others, and some practices have inherently higher functional capacity for nutrient removal than others. Currently, the relative magnitude of benefits is also more certain than the absolute magnitude of the benefits. The Stream Restoration Crediting Guidance has been developed for use and adaption by communities, recognizing the constraints and data limitations of the current state-of-the practice. The SRDB will be an important resource to help parameterize models and tools to support stream restoration planning, assessment, and crediting.

#1530. The State of the Practice for Identifying Bacteria and Nutrient Sources in Urban Waters
    • Jared Ervin as Primary Author
    • Brandon Streets as Co-Author
    • Wednesday, October 4 | 11:30 am
    • 515. WE, Room S502b
    • Abstract

Surface waters in many urban areas are frequently contaminated with elevated concentrations of fecal indicator bacteria, signaling a potential health risk, and nutrients, leading to algal growth and depleted oxygen levels that result in risk to aquatic habitat. Bacteria and nutrients are the most common pollutants on many states 303(d) lists of impaired waterbodies, and TMDLs have been established to control the contribution of urban sources in many watersheds. However, surface water concentrations may be elevated due to a variety of anthropogenic and non-anthropogenic sources. Bacteria may come from human sources (leaking sanitary sewers, improperly functioning septic systems, open defecation), domestic animals (dogs, cattle, horses), wild animals and non-fecal sources. Nutrients may come from fertilizers (urban or agricultural), human waste (sewage or septage), atmospheric deposition and natural sources. Most current illicit discharge detection and elimination (IDDE) programs, which may target both bacteria and nutrients, are not capable of identifying sources (i.e., human vs non-human). Traditional IDDE analytes, used extensively over the last decade, have been shown to be unreliable (i.e., prone to false positive and false negative results) and lead to inconclusive results in many cases. In contrast, advanced forensic tools such as DNA-based marker analyses are able to accurately detect human sources of contamination and are thus redefining how IDDE should be performed. These advanced analytes may come at a higher per sample cost compared to traditional analytes but result in long term cost savings by conclusively achieving source identification and abatement outcomes. To better assess sources, Geosyntec Consultants is using these advanced forensic tools to identify human versus non-human sources of contamination in surface and ground receiving waters. DNA-based markers and chemical sewage indicators such as pharmaceuticals and personal care products (PPCPs) are being used to identify where human sewage sources are present. Stable isotope analysis is also being used to distinguish nutrients from sewage, fertilizers, or natural sources. The use of these advanced tools in combination with traditional analytes and IDDE methods (e.g., CCTV and dye testing) allows for bacteria and nutrient sources to more efficiently be tracked and controlled. The use of multiple analytes is also advantageous in building multiple lines of evidence to more conclusively show sources are either present or absent. By efficiently tracking and eliminating sources, significant cost savings may be achieved compared to structural stormwater BMPs and green infrastructure. Until recently, the use of DNA-based markers for source tracking was primarily carried out by academic researchers. However, studies such as the Source Identification Protocol Project (SIPP), which included laboratory validation and field testing of these methods and led to the publication of the California Microbial Source Identification Manual, have led to the acceptance of DNA-based marker analysis by regulators for source demonstration. Standardized methods for the analysis of human DNA markers are currently being finalized by the USEPA. Geosyntec staff were key contributors to the SIPP study and continue to lead innovation in microbial source tracking through applied research projects such as an aging study comparing the environmental persistence of indicator bacteria, DNA markers and pathogens. Geosyntec is now one of the leaders in making this technology a common practice nationwide. This presentation will highlight the approach Geosyntec is currently using to track bacteria and nutrient sources on multiple projects including bacteria and phosphorous in the Charles River and harbor in Boston, MA, nitrate in the Ventura River in Ventura, CA, and bacteria and pathogens at beaches in Santa Barbara, CA. This presentation will also draw upon lessons learned from multiple past projects tracking bacteria, pathogens, nutrients, industrial pollutants, and other contaminants of concern in surface and groundwater across the country. Recommendations will be made regarding source tracking methods and study design components necessary to lead to conclusive and defensible results. These same recommended methodologies have recently been published in nationwide guidance documents such as the 2014 ASCE report Pathogens in Urban Stormwater Systems and the 2016 Colorado E. coli Toolbox: Practical Guide for Colorado MS4s. The study examples and guidance presented will provide important information for researchers, municipal stormwater agencies and other permitted dischargers, consultants, regulators, and water quality managers that may need to identify sources of bacteria and nutrients to impaired waters.

#1600. "What is Best in Class" Refinery Wastewater Treatment Alternatives and Operating Practices
    • Joe Cleary as Primary Author
    • David Kujawski (RW&E) as Co-Author
    • Wednesday, October 4 | 1:30 pm
    • 603. WE, Room S405b
    • Abstract

Introduction This paper discusses a refinery project in which the client asked our team the question" What is Best in Class Refinery Wastewater Treatment Alternatives" This paper will discuss the alternative treatment evaluations to upgrade the refinery wastewater treatment plant to what was defined as "Best in Class". The development of alternatives to achieve the goal was based not only on other refinery experience but also benchmarking what other industries are using for "Best in Class" to determine was is unique about refinery wastewater and what are the commonalities with other industries treating similar wastewater constituents of concern. The existing treatment plant included five rectangular oil water separators treating two separate wastewaters. The two wastewaters were then combined for dissolved air flotation and air stripping of volatile organics prior to activate sludge biological treatment with secondary dissolved air flotation and multi -media sand filtration.

Problem Statement The real driver for this project was high operation and maintenance costs for the treatment plant. The high costs which included labor and contractor costs to provide removal of oil and solids from the various DAF units which were not operating efficiently as designed. Temporary facilities had to be installed during the cleaning operations since no redundant units were available. There were also high costs for a temporary thermal oxidizer when the one unit had to be taken down for repairs every few years. The client was not happy with the temporary fixes and the high costs and wanted to evaluate what would be the costs for a "Best in Class" treatment upgrade which would include redundant units if needed during temporary shutdowns for repairs. The key wastewater constituents of concern for refinery wastewater include: COD, oil and oily suspended solids, total dissolved solids, volatile organics, selenium, and mercury.

Approach The approach to developing the treatment upgrade options is to first review the treatment operating and performance data and the costs of the repairs. Two site visits/workshops were then conducted to work with the local refinery team of stakeholders. A collaborative team approach was utilized to develop consensus and prioritize the key issues and problems and the design basis for developing the treatment solutions. METHODS Treatment alternatives or methods that were evaluated during the project included the following:

  • Rectangular and circular oil water separators
  • Activated sludge upgrades for nitrogen removal using anoxic zones and conversion to MBR
  • Use of the aeration basin instead of the thermal oxidizer to control VOC emissions from the aeration basin
  • Upgrading to MBR instead of repairing and adding additional secondary DAF capacity

Results The results or the alternative comparisons for the oil water separators types are shown in Tables 1 and 2 cost comparison. For the VOC emissions control, a comparison of the existing thermal oxidizer capacity upgrade to activated carbon and the VOC biotreat technology in which the aeration basin biomass is used to biodegrade the VOCs versus stripping is shown in Table 3. A comparison of nitrogen removal alternatives including MLE and MBR upgrades will be presented in the paper.

Conclusions

  • The "Best in Class" technologies identified for refinery wastewater for treating COD and nitrogen are essentially the same as those in other industries such as activated sludge and MBRs.
  • The "Best in Class" technologies that are unique for refinery wastewater are the oil water separators and the VOCs stripping prior to the biological treatment and the VOC Biotreat technology which uses the activated sludge aeration basin as a VOC treatment process instead of stripping the VOCs to a thermal oxidizer
Risk Based Analysis and Modeling of Final Clarifier Performance
    • Chris Robinson (Joe Cleary presenting on his behalf) as Primary Author
    • Joe Cleary, Darrell Egarr, and Andrew Staszak as Co-Authors
    • Risk Based Analysis and Modeling of Final Clarifier Performance
    • Wednesday, October 4 | 4:30 pm
    • 605. WE, Room S402b
    • Abstract

Intorduction In this work, we have applied a risk-based technique to the performance analysis of existing Final Settlement Tanks (otherwise known as: FSTs or final clarifiers) at a UK wastewater treatment works. The aim of the work was to determine the risks to the operator in terms of failure to meet environmental compliance for the final effluent discharge form the wastewater treatment works. The works is in the north of England and serves a population equivalent of 95,000. The site uses a carbonaceous activated sludge process and has four FSTs, each 32 m in diameter with a 2.3 m side wall depth, 7.5° floor slope and scraper system to move settled solids to the central hopper. In a preceding study, we had carried out computational fluid dynamics (CFD) modeling on the final tanks. In the models we tested whether McKinney baffles or Energy Dissipating Influent devices could improve blanket depth and effluent suspended solids concentration, but found that these would not provide the security of performance required at the site. To provide assurance that the FSTs could continue to be operated, we proposed a Risk Based Analysis of the tanks' performance and determine what the "availability" of the tanks would be. This would hence determine whether the tanks' continued use would be acceptable and any solids loading limits that should be applied to the tanks in future. In this context, the "availability" of the tanks is defined as the percentage time that the tanks can be operated without ESS rising above the consented limit.

Technical Approach Risk Based Analysis is a statistical method used to determine performance of different systems and allows operators to make informed judgements regarding their safe operation. In this context, risk is defined as: Risk = (frequency of event) x (consequence) Frequencies are normally assessed on a per annum basis. The "consequence" is generally specific to the industry or system being studied; for final tanks the consequence can be defined as "tank failing" or "ESS exceeding consented limit". The units of risk then become "failures per annum" – and this also defines the "Availability" of the tanks as the percentage of the year that the tanks can be operated without exceeding consented Effluent Suspended Solids (ESS) limits. The key to any risk-based study is to calculate a sufficiently large number of operational scenarios so that an accurate statistical study can be carried out. There were a number of stages in the overall analysis which require different methods. The first stage was to review site operational data and determine appropriate ranges for the of different FST operating conditions: • forward flow rate; mixed liquor suspended solids concentration (MLSS); return activated sludge (RAS) concentration; and stirred solids volume index (SSVI3.5). In addition to determining the appropriate ranges for these values, the site data was also used to work out the frequency of occurrence of different operating conditions. In total, 54 operating conditions were defined to encompass the range of performance required. Each of these operating conditions was then modeled using computational fluid dynamics (CFD) to determine the blanket depth and effluent suspended solids (ESS) concentration and hence whether the tank met its discharge compliance for those flow conditions. Once the CFD analysis had been completed, the results could be assembled with the frequency data to determine the probability of failure of the FSTs, the availability of the tanks and also to understand what ranges of operation gave stable and unstable performance.

Results CFD model results lend themselves to being presented graphically and contour plots of sludge concentration are shown here for a small sample of cases in Figure 1. This show a half-section through the diameter of the FST with contours of the concentration of activated sludge solids presented on a log scale: red represents well-settled solids; orange/yellow indicates diffuse solids and blue/green represents the supernatant. Figure 1 shows the results from different cases with identical flow conditions except sludge settleability (SSVI). There was good settling with a number of distinct layers with different solids concentration and the blanket forming below the level of the stilling well for the case with SSVI = 110 mL/g; however, there is poor settling with a high concentration dispersed throughout the tank, when the SSVI rises to 140 mL/g. When the SSVI = 80 mL/g with the blanket low in the tank. In all these cases, it is apparent that the high-energy flow within the stilling well tends to stir up solids above the hopper, reducing settleability and increasing effluent suspended solids, ESS. (The ESS concentration for each case is the sludge concentration at the outlet weir, calculated in the models.) The CFD results for ESS concentration and blanket depth from each of the 54 cases were plotted against the solids loading limits determined using mass flux theory (MFT) and are shown in Figure 2. The plot shows that there are a large number of cases with ESS clustered just below the ESS consent limits; also, that nearly all cases have the blanket within the 0.5 m limit. The first cases which exceed ESS = 30 mg/L do so at around solids loading rate of 62%. This is an important result as it demonstrates that the true performance limit measured by solids mass loading rate is 62%, not 80% (which is the commonly assumed value in the UK). It also means that a 38% safety factor (not 20%) must be applied to the tanks and that they cannot be loaded as highly as experience may tell from other sites. The red squares in Figure 2 which are to the left of 62% solids mass loading rate are the "successful" cases. The sum of the probability of occurrence of these cases is the "availability" of the tanks - or portion of the year that the tanks currently operate without exceeding ESS = 30 mg/L. From this the availability of the tanks was calculated as 94.2%.

Relevance The work shows how risk-based analysis is an appropriate method to determine whether the operational performance of wastewater processes is suitable when looking at the whole range of operations and the probability of failures occurring. It also demonstrates as computational fluid dynamics can be used as a design tool to provide data for a wider analysis, rather than simply for testing individual process operation points.

More Information

For more information regarding the event, visit: https://www.weftec.org/
For more information on water quality, contact Adrienne Nemura at This email address is being protected from spambots. You need JavaScript enabled to view it..
To learn more about Adrienne see her profile at: https://www.geosyntec.com/people/adrienne-nemura

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Geosyntec is a specialized consulting and engineering firm that works with private and public sector clients to address new ventures and complex problems involving our environment, natural resources, and civil infrastructure.

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