Location: Room 130 |
|10:30am - 12:00pm||Session 06A: Facility Operations|
Location: Room 130
10:30am - 11:15am
Operations and Maintenance Initiatives in the Water Environment Federation
Clean Water Services, United States of America;
The Water Environment Federation (WEF) sets forth Critical Objectives and Strategic Goals in order to achieve its vision of “A community of empowered professionals creating a healthy global water environment.” One group of the envisioned empowered professionals is facility operations and maintenance (O&M) staff. A number of programs have been initiated by WEF to support and address the issues currently facing the O&M sector of the industry.
As a whole, these programs attempt to focus on recruitment and retention of operators, education and training for operators and operator trainers, recognition for operators, certification exams, and certification reciprocity. Programs are executed through WEF committees and task forces such as the Operators Advisory Panel (OAP), the Plant Operations and Maintenance Committee (POMC), and the House of Delegates (HOD).
The success of these programs can be limited in several ways. First, many O&M staff are only registered at the member association (MA) level, and therefore are unaware of and have no access to the resources available at wef.org. Second, the activities of these committees are guided to some degree by the personal views and experiences of committee members, and may not necessarily align with issues prioritized by O&M staff. Third, O&M certification is handled by the states as is approval of continuing education units (CEUs) needed to maintain certification. The difficulty in issuing CEU accreditation devalues the national level education resources.
The Covid-19 pandemic has halted in-person trainings but affords opportunities in distance learning and greater exchange of ideas that we must use to our advantage.
This session, presented by the immediate past chair of the WEF POMC, will introduce the general structure of the WEF groups addressing O&M issues and highlight the major issues of concern. The resources and benefits of full WEF membership will be demonstrated. The session is then intended to proceed to an extended (15-20 minute) interactive discussion with the audience (hopefully dominated by O&M staff and managers) that will garner feedback about the value of various programs and initiatives and inform what issues truly are of high concern to O&M staff.
11:15am - 12:00pm
“Plan the Work, Work the Plan” Start up of the Tri-City Solids Handling Improvement Project
Water Environment Services, United States of America;
In 2015, Clackamas Water Environment Services (WES) kicked off a project to completely overhaul and expand the solids facilities at the Tri-City Water Resources Recovery Facility (TCWRRF). The project constructed a new 1.3 million gallon digester, dewatering facilities and a combined heat and power system. Two existing digesters are also being upgraded. During the project development, WES operations staff was integral in developing the construction constraints included in the construction bid package. To accommodate the constraints identified, the start-up of the project was separated into two phases. Phase 1 of start-up, was completed in December of 2020, included the new digester, centrifuges, polymer systems, boilers, and dewatering feed tank. Phase 2 of the project, scheduled to begin in April 2021, will include making the upgrades to the two existing digesters, addition of a digester feed tank and replacement of the co-generation system.
Because digestion facilities must remain online and reliable during construction, significant coordination effort between engineering, operations and construction team members has been required throughout the project. This presentation will provide an overview of the project and the challenges there were being experienced prior to this project, it will cover in detail the approach to planning and coordination between the operations staff, contractor, and engineer during design, construction, and execution of both phases of start-up. The presentation will include lessons learned from all three perspectives as well as an update on the operational performance of the new facilities.
|1:15pm - 2:45pm||Session 06B: Facility Operations|
Location: Room 130
1:15pm - 2:00pm
Creating an Electronic O&M Manual for Pierce County’s Chambers Creek WWTP
1Brown and Caldwell; 2Pierce County Planning and Public Works; , ,
Plant operations and maintenance manuals are often voluminous, stored in cumbersome hard copy binders, or saved as a multitude of electronic files which must be separately opened and browsed, and often neglected because they are difficult to update contemporaneously.
The Pierce County Project Team collaborated to create an IT solution for the operation and maintenance documentation needs of the recent Chambers Creek Regional Wastewater Treatment Plant Expansion (CCRWWTP). The team envisioned and executed an online electronic operations and maintenance (eO&M) manual. The eO&M consolidates and integrates all content related to the plant expansion, including engineer’s technical operations manuals, original equipment manufacturer (OEM) O&M manuals, record drawings, SCADA control modules, emergency response protocols, and plant related ancillary libraries. The eO&M is hosted on Amazon Web Services (AWS) and utilizes the OMS-Connect software platform. The CCRWWTP eO&M was structured as an evolving, living document designed to be appended by the County.
This presentation will provide an overview and online demonstration of the Pierce County CCRWWTP eO&M, discussing functionality, enhanced user experience, lessons learned, and tips and tricks for future eO&M authors. Modernizing O&M Manuals is important to sustained utility operations in the information age.
2:00pm - 2:45pm
CFD Modeling for Trickling Filter/Activated Sludge Secondary Clarifier Optimization
1Hazen and Sawyer; 2City of Salem, OR; ,
Clarifier CFD modeling is relatively common, however, most secondary clarifier studies are conducted in an activated sludge application. Trickling filter effluent (TFE) has different characteristics than conventional activated sludge. To the knowledge of the authors, a similar case study to the one presented here for the evaluation and optimization of TF clarifiers has not been presented before. This study is unique and presents a detailed analysis of settling and flocculation properties of TFE and the application of secondary clarifier CFD modeling to establish clarifier capacity and identify optimization strategies.
The City of Salem’s Willow Lake Water Pollution Control Facility (WLWPCF) has a permitted capacity of 35-mgd average dry and 155-mgd design peak wet weather flow. The City budgeted for clarifier rehabilitation due to ageing mechanical equipment but desired to understand clarifier capacity limitations and evaluate whether modifications could expand existing available capacity.
Hazen conducted stress tests and developed calibrated CFD models for the secondary clarifiers. Model calibration was based on an extensive clarifier testing protocol to simulate peak clarifier loadings, characterize sludge settleability and flocculation properties, and evaluate performance. This work included field testing, zone settling, flocculation and dispersed solids testing.
After development of the CFD models, the clarifiers were evaluated to determine available capacity with the current geometry and mechanism type. Optimization strategies such as the addition of energy dissipating inlet wells, modifications to the flocculation well sizing, and the addition of baffling were evaluated. The City used these results to tailor capital planning for clarifier rehab projects and re-evaluate wet weather capacity and operating strategies at the WLWPCF. Based this work, improvements were identified to potentially expand the combined clarifier peak flow capacity from approximately 105 mgd to over 140 mgd.
|3:00pm - 5:15pm||Session 06C: Wastewater Process|
Location: Room 130
3:00pm - 3:45pm
Meeting Stringent Ammonia and Disinfection Byproduct Limits with Preformed Monochloramines
1Jacobs, United States of America; 2Clean Water Services, Oregon; ,
The Rock Creek Advanced Wastewater Treatment Facility (RCAWWTF) must balance low effluent ammonia limits, disinfection requirements, and potential low disinfection byproduct (DBP) limits.
The ammonia and disinfection limits are currently met through stable nitrification and use of sodium hypochlorite (SHC) disinfection, respectively. Effluent characterization identified the presence of two trihalomethane DBPs of potential regulatory interest when effluent ammonia concentrations were low: bromodichloromethane (BDCM) and chlorodibromomethane (CDBM). Initial estimates suggest that future discharge limits for CDBM and BDCM may be as low as 1.1 µg/L and 1.5 µg/L, respectively.
Preformed monochloramine (PFM) disinfection was identified as an operational strategy for reducing DBP production. This method utilizes monochloramines that are formed by mixing ammonia and sodium hypochlorite in carrier water before mixing with process water, greatly reducing the opportunity for DBP formation. Bench-scale testing followed by pilot testing was conducted to determine if utilizing a PFM disinfection approach could be an effective solution.
Preliminary bench-scale testing of insitu monochloramines (ISM) versus PFM indicated that PFM was a promising option to meet the disinfection and DBP formation goals; therefore, pilot-scale testing was pursued.
A flow-through pilot system was constructed at the RCAWWTF to receive tertiary effluent where a PFM solution could be added. Testing evaluated:
Testing demonstrated the benefits of using PFM over free chlorine and ISM by meeting disinfection permit limits and significantly reducing DBP formation potential while still maintaining effluent ammonia concentrations that met permit limits. These results show the viability of implementing PFM disinfection as a solution to more stringent DBP limits. Other clean water utilities may benefit from modifying existing chlorine disinfection to PFM disinfection as a much more cost-effective alternative relative to converting to another disinfection technology.
3:45pm - 4:30pm
BNR Conversion of the Oro Loma/Castro Valley Water Pollution Control Plant
Kennedy Jenks, United States of America;
Maintaining reliability in aging infrastructure has become a significant investment for wastewater agencies as facilities approach the end of their useful life. One such agency, Oro Loma Sanitary District (OLSD), was faced with a significant investment to rehabilitate a 7-mile long 189 MGD deep-water outfall in San Francisco Bay shared by six agencies. At the same time, nutrient regulation was being considered through a region-wide watershed permit that would require higher levels of treatment at OLSD’s 20 MGD Water Pollution Control Plant (WPCP). OLSD identified a project that would address these two challenges.
Implementation of $26M biological nutrient removal (BNR) upgrade of the existing secondary treatment process allowed OLSD to cost-effectively comply with anticipated regulation in the future watershed permit for nitrogen removal. In addition, an improved effluent quality allowed OLSD to renegotiate its NPDES permit to allow for the use of a near-shore outfall during wet-weather as an alternative discharge location to the deep-water outfall. Permitted use of the alternative outfall allowed OLSD’s partner agencies additional capacity in the shared deep-water outfall, as well as reducing OLSD’s liabilities for future outfall maintenance. The BNR upgrades were designed and constructed over a 3-year period and went into operation in September 2020.
This presentation will highlight how BNR was incorporated into the WPCP, the anticipated benefits of the project, and how the improvements are performing based on the first months of operation.
4:30pm - 5:15pm
Primary Sludge Fermentation: A Wretched Hive of Scum and Villainy
Clean Water Services, United States of America;
The Unified Fermentation and Thickening (UFAT) process is used at two Clean Water Services (CWS) Resource Recovery Facilities (Rock Creek and Durham) for primary sludge fermentation, generating volatile fatty acids (VFA) to support biological phosphorus removal. The Durham plant has a problem with fermenter scum buildup, forming dense mats during warm periods; a problem not shared by the Rock Creek fermentation system. The goal of this project was to inform design decisions on an upcoming fermenter expansion at the Durham plant by clarifying the role played in scum mat formation by three significant design differences between the facilities: 1) sludge heating, 2) sludge screening, and 3) scum removal.
Laboratory experiments using heated primary sludge reactors showed a correlation between scum mat formation and temperature, with mats forming more quickly with increasing heat. Observations of gas bubbles caught in and under scum mats in the laboratory and at full-scale suggest that solids from the sludge blanket may be floated to the surface of the fermenter by biologically-generated gas during fermentation. Laboratory experiments also showed that unscreened primary sludge produced scum mats more quickly than screened sludge, and that these mats persisted longer. Unscreened Durham primary sludge contains irregular, thread-like solids like hair and fibers. We observed these in dense formations in the full-scale mat, suggesting that they provide a structural matrix for scum to congeal to, trapping gas bubbles.
Our observations suggest that gas production from fermentation activity causes solids from the sludge blanket to rise to the surface, creating or exacerbating scum mats. The fermentation process is accelerated at warm temperatures, which is likely why mat formation worsens during warm periods. Screenable solids also likely play a substantial role in providing a stabilizing network for scum solids to adhere to, worsening scum problems at plants that do not utilize primary sludge screens. Installation of capital improvements such as sludge screens and scum handling systems are multi-million dollar investments; this work offers valuable insight into the roles played by fermenter design differences in mitigating scum accumulation and can inform design decisions regarding installation or improvement of UFAT fermentation systems.
|8:00am - 9:30am||Session 11A: Planning|
Location: Room 130
8:00am - 8:45am
Use of Integrated Planning to Facilitate an NPDES Permit Renewal
1Clean Water Services, United States of America; 2HDR Inc; ,
Wastewater and stormwater utilities face significant challenges to manage aging infrastructure, meet customer expectations, and address regulatory obligations. The U.S. Environmental Protection Agency (EPA) recognized that municipalities could more efficiently use their resources to make important, cost-effective environmental improvements that align with community priorities. To support communities in these efforts, EPA released the Integrated Municipal Stormwater and Wastewater Planning Approach Framework. Since its inception, Integrated Plans have primarily been used by communities in response to enforcement actions to address combined sewer overflows. More recently, EPA has encouraged the use of Integrated Plans as part of the NPDES permitting process. Clean Water Services has developed an Integrated Plan for submittal with its NPDES permit renewal application. The goal of this Integrated Plan is to establish a long-term permitting strategy to prioritize and schedule actions well into the future to proactively address the challenges it faces. Following EPA’s model, Clean Water Services’ Integrated Plan includes key items like watershed assessment, watershed objectives, challenges, public outreach, and adaptive management. Unlike many other Integrated Plans, Clean Water Services’ plan is not driven by wet weather compliance issues. It therefore provides an example to other utilities that want to use the Integrated Planning framework to establish a long-term permitting strategy.
8:45am - 9:30am
Regionalization for Economic Development and Watershed Protection
Keller Associates, Inc., United States of America;
Failing septic systems can be a significant health hazard to both the septic tank owner and downstream residents. Additionally, the amount of land needed for drain fields makes it difficult to attract new businesses and developers. For some communities, their financial situation prohibits the addition of a city sewer system. Moreover, for residents of the North Santiam Canyon region of Oregon, The Three Basin Rule (OR 340-041-0350) makes it even more challenging to convert to a community-based sewer system. This rule prohibits additional surface water discharges to certain rivers, including the North Santiam River, which supplies drinking water to the City of Salem. Add to all this the recent wildfires that devastated this North Santiam Canyon region and bring up additional questions about rebuilding.
A regional solution to address these regulatory and financial issues has gained traction in the past few years. With the support of Marion County and the Mid-Willamette Valley Council of Governments, the communities of Detroit, Gates, Idanha, and Mill City have engaged in discussions regarding the possible incorporation of a regional system sewer system. In January 2017, a regional sewer system feasibility study was completed. A master plan is currently underway, and these entities are in the final steps of establishing a “sewer authority.” This presentation will discuss the difficulty in developing a regional sewer system in this mountainous area, the challenges of creating a sewer authority among the communities, and the steps needed to protect this critically important drinking water source. Added to this will be navigating the planning process during and after the recent wildfires in the canyon.
|10:30am - 12:00pm||Session 11B: Industrial Pre-Treatment|
Location: Room 130
10:30am - 11:15am
Trading Futures for Long Position on BNR Performance
1City of Boise; 2HDR; ,
Wastewater Recovery Facilities (WRRFs) can leverage permitting, integrated planning, and water quality trading to stabilize biological nutrient removal (BNR) performance. Collection system industrial inputs affect BNR at WRRFs. A renewed emphasis on states’ involvement in Clean Water Act regulation has stimulated efforts to establish innovative sewershed nutrient management strategies. Water quality trading has been documented by EPA since the early 1990’s, but recent emphasis has led to consideration of pretreatment trading in the context of nutrient management at the WRRF. Integrated planning is a final piece of the puzzle, having recently been added to federal law as an amendment to the Clean Water Act.
Pretreatment allocations for discharge to a WRRF have the potential to de-stabilize otherwise robust BNR systems. The West Boise Water Renewal Facility (WBWRF) received high nitrate concentrations through a long collection main, allowing for depletion of readily biodegradable carbon. The resulting impact at WBWRF was a severe diurnal variation in raw influent volatile fatty acid (VFA) concentration, with typical levels of 23 mg/L VFA at midnight and 4 mg/L VFA at 11:00AM. This effect was verified through a robust collection system sampling effort which captured diurnal phosphorus and nitrogen species concentrations at strategic points in the collection system, showing correlation with periods of decreased VFA. The collection system nutrient study also characterized transformation of nutrient species, so that collection system kinetics could be quantified and modeled as a “plug-flow” reactor system in which nitrogen, phosphorus, and VFA species change over time. The study provided further context for implementing a successful pretreatment program.
This effort was paired with a pretreatment trading evaluation. H.R. 7279 amended the Federal Water Pollution Control Act to allow permitting authorities to incorporate integrated planning into renewed permits. The scope of the amendment highlights pretreatment trading in which the permitted WRRF administers a trading program for industrial users. The City undertook an evaluation which showed that trading of nitrogen and phosphorus credits in an exchange open to industrial users could potentially result in net economic benefit while reducing the nutrient headworks loading faced at the WBWRF.
11:15am - 12:15pm
Development of Facility-Specific Zinc and Copper Nitrification Inhibition Thresholds for Local Limits Analysis
Clean Water Services; ,
Controlling industrial discharges to a Publicly Owned Treatment Work (POTW) is an integral part of the NPDES permit program. POTWs conduct a local limits analysis to establish limits for industrial users. Factors that are considered in this process include water quality standards, water quality-based NPDES permit effluent limits, biosolids use and disposal, and the potential for inhibition of biological processes within the treatment plant. Nitrifying bacteria are often highly sensitive to environmental stressors and pollutants, and local limits are frequently driven by the need to protect the biological nitrification process.
The U.S. EPA has published nitrification inhibition threshold values for a variety of substances in its Local Limits Development Guidance (EPA, 2004). For many substances, a wide range of possible inhibition levels have been identified. However, because these data are decades old and studies are not well documented, there is limited confidence that even the most conservative thresholds would be protective of biological treatment processes. Additionally, use of the most conservative values can result in overly stringent local limits that place a significant burden on industrial users.
Clean Water Services (CWS) is in the process of revising local limits for its four wastewater treatment facilities (WWTFs). Three CWS facilities have ammonia limits and rely on nitrification to meet these limits. Copper and zinc were of particular interest due to prior operational data. Preliminary analysis suggested that local limits for these metals would likely be driven by the nitrification inhibition threshold. At times, CWS WWTFs have experienced copper and zinc levels higher than the minimum threshold concentrations in the EPA Guidance with no discernable impact to the biological processes.
In order to establish site-specific inhibition levels, CWS conducted nitrification rate testing using two methods: a modified version of ISO 9509:2006 and a simplified respirometry protocol. Biomass from the three nitrifying WWTFs was spiked with varying concentrations of zinc and copper. Results were analyzed to determine nitrification inhibition thresholds. The resulting facility-specific nitrification inhibition levels were higher than the EPA-published minimum thresholds for both metals while providing confidence that local limits would be protective of biological nitrogen removal processes at each WWTF.
|1:15pm - 2:45pm||Session 18A: Utility Planning|
Location: Room 130
1:15pm - 2:00pm
Your Crystal Ball – How Cloud-Based SCADA Allows Operators To See The Future – And Avoid Problems
Collection systems play a critical role in public health. Aging underground sanitary and combined sewer systems are prone to infiltration, inflow, and stormwater runoff, while lift stations are overwhelmed by a rise in personal care wipes which wreak havoc on the pumps. As regulatory frameworks become more stringent, agency staff must do more to maintain compliance.
The rise in IIOT (Industrial Internet of Things) technology makes it possible to combine remote sensors and cellular communications with the power of cloud computing. Cloud-based SCADA systems allow operators to monitor conditions, receive alarms, control equipment, and view data and trends. We will examine case studies from two agencies that have used cloud-based SCADA to improve their operations and lower the risks of overflows.
Concerned about excessive false alarms from an auto-dialer system, a Southern California Community Services District turned to a cloud-based SCADA system in an effort to gain better visibility into the system and reduce overtime callouts. The cloud-based system allowed them to monitor wet well levels, pump statuses, and AC power remotely from their mobile phones and tablets. The District gained greater visibility by integrating their remote sewer level data into the cloud-based SCADA platform’s user interface. Gaining insight into pump run times before, during, and after rain events enabled District staff to visualize the impacts of inflow and infiltration on their system. The upstream sewer water level data also gave the staff a heads-up in terms of the downstream impacts on the wet wells and lift stations during storm events.
Another Community Services District used a cloud-based SCADA system to calculate the volume of raw sewage they were delivering to a neighboring agency for treatment to reconcile service fees. The system provided district staff with alarms during a power outage when malfunctioning equipment threatened to overflow a lift station. The high water and loss of power alarms received via SMS text and email-enabled staff to get generator power up and running to avoid an overflow event.
Much like a crystal ball, cloud-based SCADA systems allow operators can monitor conditions remotely and take proactive measures to maintain their systems.
2:00pm - 2:45pm
Is your Utility Looking to Improve? There’s a WISE way to join your Peers!
Clean Water Services, United States of America;
WISE, the Water Intraprenuers for Successful Enterprises Program, is a comprehensive framework and methodology that helps utilities create value and improve performance. Now an on-going effort housed with the Water Environment Federation, the program was a project called Utility Analysis and Improvement Methodology (UAIM) that was sponsored by the Water Research Foundation (WRF) and the Leaders Innovation Forum for Technology (LIFT). This collaborative effort includes leading utilities from all over the U.S. including Clean Water Services and the City of Portland, as well as utilities in Denmark, Canada, and the United Kingdom. This comprehensive approach to improve management and performance in water sector utilities includes the development of a business reference model that also helps us determine how to better leverage information technology systems, and research into topics related workforce and organizations. This is a multifaceted approach that considers different execution timeframes – including operational, tactical and strategic. One of the greatest strengths of the WISE program is the collaboration among the participating utilities: the Utility Partners. Subject Matter Experts from a number of utilities have created models of processes and practices for Capital Improvement Programs, Asset Management, capital project Business Case Analysis, and several other topics. The presentation will include an overview of the methodology and several case studies where utilities have successfully employed elements of the approach. Learn how you can become part of the consortium of utilities improving their business practices in meaningful and comprehensive ways.
|3:00pm - 4:30pm||Session 18B: Utility Planning|
Location: Room 130
3:00pm - 3:45pm
Affordable Housing and Tiered Development Impact Fees
Water Environment Services, United States of America; ,
One of the emerging issues in utility management and capital financing is how to address the impact of affordable housing on a wastewater system. Utilities often receive pressure to waive or reduce development impact fees for what is seen as more desirable or diverse and potentially more equitable housing supply. This is counterbalanced by the challenge that if those developments do not pay for the cost of their impact to the system, another segment of the customer base will. This leaves the utility stuck between two valid policy goals and leaving both groups unhappy with any changes made.
To create a path forward, Clackamas Water Environment Services (WES) explored a more nuanced effort to measure the impact of housing size as a proxy for water consumption on the wastewater system. As a regional wastewater system crossing multiple water providers, WES does not assign equivalent dwelling units (EDUs) based on direct water consumption data, but used the traditional “a house is a house” model with a 20% discount for multi-family dwellings. WES pulled winter water consumption data from several underlying water providers, then cross-indexed with census data and home size information to create a model of flow contributions to the system.
WES found a statistically significant difference in wastewater discharges that correlated to the size of the dwelling, with small 800 square foot dwellings at one end and 3000 square foot dwellings at the other. After slicing the data several different ways, WES established key deviations from the baseline consumption of a 2000 square foot home. These deviations supported the creation of a 5-tiered EDU assignment (and therefore development impact fee assignment) for new development that reduced the cost of affordable housing, and increased the cost of large homes.
This nuanced distinction created a path forward to enabling lower affordable housing fees while having a strong, evidence-based approach that there was no subsidy being given by another customer segment. WES proposes to share how the analysis was done, how to draw conclusions from the data, and how to implement a tiered development impact fee structure.
3:45pm - 4:30pm
Five Things to Know About Saving Ratepayers Millions of Dollars with WIFIA
Murraysmith, United States of America; ,
Every water and wastewater utility in the United States should be aware of and consider participating in the Environmental Protection Agency’s Water Infrastructure Finance & Innovation Act (WIFIA) loan program. The benefits to your community and ratepayers can have generational impact. Our staff has supported more than $1.4B in WIFIA loan Letters of Interests and subsequent applications. This presentation covers the five things utilities should know about WIFIA:
Attendees of this presentation will have the information they need to take a closer look at WIFIA funding for their agency, potentially saving their ratepayers millions—or hundreds of millions—in interest payments