Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
Location: 410ABC |
|Date: Monday, 13/Sept/2021|
|10:30am - 12:00pm||Session 04A: Resource Recovery|
10:30am - 11:15am
Beyond Net Zero – Reaching the Next Level of Renewable Energy through Beneficial Use of Food Waste
The City of Gresham (City) Wastewater Treatment Plant (WWTP) is a 15 MGD facility located east of Portland, Oregon. The plant accepts and co-digests fats, oil, and grease and beneficially uses their biogas to fuel a combined heat and power system to achieve energy neutral status and they are evaluating how to go beyond net zero. The existing two mesophilic anaerobic digesters at the facility are currently at capacity and in need of an expansion to accommodate projected future loadings for city growth as well as to provide redundancy.
A recently adopted policy by Metro (regional entity) requires mandatory segregation, collection, and alternate processing (not landfilling) of food waste that is generated by businesses within the Portland metropolitan area. The City conducted a study to explore the financial payback options for a digestion expansion project that could fulfill the City’s capacity needs, accept food slurry from Metro’s food waste program (or other liquid organic waste sources), and beneficial use of the additional biogas produced.
The study assessed potential cost and non-cost benefits and impacts associated with additional liquid organic waste loading on the WWTP, digestion alternatives, sidestream recycle loading to the liquids treatment, solids dewaterability, biogas production, and biosolids end use. The study included a business case evaluation considering economic, environmental, social, and operational impacts to assess the favorability of pursuing the selected alternative. Finally, the study included a conceptual design for the selected alternative.
The study has shown that the City could spend 16 million dollars and construct a third mesophilic digester for capacity needs and not accept additional feedstocks nor receive a payback on the investment. Alternatively, the City could spend approximately 30 million dollars to convert two existing digesters to thermophilic technology, construct a third thermophilic digester, expand feedstock receiving, expand cogeneration, and obtain a payback on investment under 10 years by utilizing State incentive programs. The City is planning to conduct a predesign to further refine liquid organic waste availability, revenues and costs, and funding sources for the project.
11:15am - 12:00pm
Linking Anaerobic Digester Microbiomes With Resistance To Organic Overloads
Oregon State University, United States of America; email@example.com
Anaerobic co-digestion has become a popular option to increase biogas production, thus increasing recapture potential, with grease trap waste, or FOG (fats, oils, and greases), showing the highest methane production potential. In order to ensure reactor stability and optimal performance, the correct microbiome composition is essential. However, it is currently unknown what microbiome compositions are optimal for co-digestion nor what operational parameters are most effective at creating these optimal structures. This work monitored nineteen full-scale anaerobic digesters, at six separate facilities, monthly for one year to link operational characteristics with microbiome composition. Of the nineteen digesters studied, three perform FOG co-digestion, four perform co-digestion with biodiesel wash water, one is fed only TWAS (thickened waste activated sludge), and the remaining eleven are fed primary sludge and TWAS. Microbiome composition was analyzed using 16S rRNA amplicon sequencing. Operational data from each of the full-scale facilities (including pH, alkalinity, volatile fatty acids, detention time, temperature, total and volatile solids, free ammonia, organic N, dissolved P, organic P, chemical oxygen demand, and gas production) was examined to determine their influence on microbiome compositions.
Batch resistance assays were created to link microbiome compositions with digester functionality in response to organic over loadings. For each full-scale anaerobic digester tested, twenty-five 100 mL batch anaerobic digesters were used for batch resistance assays. Five batch anaerobic digesters were ran as digestate-only controls, and the remaining twenty were fed 1 mL, 5 mL, 10 mL, and 20 mL of canola oil (in quintuplet). The rates of methane production and methane content of the biogas were used to calculate the functional resistance of each full-scale anaerobic digester. The batch resistance assays were performed in winter and summer to account for seasonal variations in full-scale plant operation and microbiome compositions.
|1:15pm - 2:45pm||Session 04B: Energy Recovery|
1:15pm - 2:00pm
The Future of Meeting Permit with Energy Efficient Operations is Here
Cascade Energy; firstname.lastname@example.org
While energy hasn’t been on everyone’s radar in the past, thinking about energy use and ways to operate more efficiently is becoming more common. Many WRRFs have made no and/or low-cost operational changes to save energy without sacrificing water quality. Some have overcome barriers including the “this is the way we’ve always done it” thinking. Hearing success stories about facilities who have made small changes that led to significant energy savings might just be the help you need for your facility. Even folks who think their facilities are already optimized have found ways to save energy through strategic energy management. This presentation will focus on typical energy saving opportunities at WRRFs. Real world examples of projects implemented in the Pacific Northwest will be shared.
2:00pm - 2:45pm
Lewiston, Idaho Revamps their Aeration Basins to Save Energy and Improve Process Control
Lewiston, Idaho's wastewater treatment plant dates back to the 1950s, and surprisingly several of the original components are still in operation today. Although the equipment had been maintained, several equipment failures, and the associated emergency repairs, opened the City's eyes to the need for additional investment. One of the largest expenses for the facility was the aeration basins. The City utilized coarse bubble diffusers and controlled the aeration using manual operator adjustments. Additionally, the aeration capacity was insufficient, leading to several process upsets.
Over the past few years, the City made several critical decisions to improve its aeration basin system. Their approach eventually led to the construction of a new treatment process configuration within the existing basins. Additionally, the mixing, aeration, and aeration controls were all replaced to reduce energy usage and improve process control. The improvements, including compressed gas mixing and ammonia-based aeration control, have recently started up on the approximately $35 million project. This presentation will discuss the steps the City went through, their decision-making procedure to select the equipment, and the process and energy improvements that have been observed.
|3:00pm - 4:30pm||Session 04C: Facility Operations|
3:00pm - 3:45pm
Development and Deployment of Gamified Simulation Software for Training Wastewater Operators - Cancelled
Maia Analytica, Portland, OR, USA; email@example.com
As wastewater treatment has evolved, treatment operations have continued to become increasingly complex. At the same time, our understanding of the environmental, public health, and economic impacts of improperly treated wastes has grown, decreasing tolerance for disruptions. This means new operators are entering into an increasingly demanding environment in which they may not have much time to learn through trial and experience on the job. Additionally, operators are facing these challenges as the work is aging - stressing existing operator training norms. New methods for training operators are needed to help train the changing workforce. Process simulators are particularly well suited to illustrate the complex interrelationships inherent to advanced treatment systems that aren’t obvious or intuitive to new operators. Simulators allow operators to explore the consequences of operational decisions across the facility in an interactive, risk-free way. The emerging generation of operations professionals has shown an increasing affinity for hands-on, computer-based training and games provide an additional level of engagement and motivation that improves learning outcomes.
In this work we present a gamified simulator software called Wastewater Integrated Learning Management Activity (WILMA) designed to help operators learn the uniqueness of the system they will be operating, opposed to a generic treatment system. Engineers worked with partners at a full-scale facility to understand what is required to make informed decisions and analysis then designed mini-games around those decision points. Gamification of WILMA significantly improves engagement and motivation, both key pieces of improved learning outcomes. The game design and user interface is based on cognitive science research and state of the art visualization methods. Overall the presentation demonstrates and provides an example of training tools for the future of the wastewater workforce.
3:45pm - 4:30pm
Improving Operations at an Aging and Overloaded WWTP
Wallis Engineering; firstname.lastname@example.org
As small communities grow, increases in wastewater loads can create outsized problems for their wastewater treatment plants. Over the last decade, the City of Stevenson wastewater treatment plant has seen dramatic increases in wastewater BOD and TSS loads and highly variable influent pH. This change in wastewater characteristics was driven by high strength users, including restaurants and beverage industries. Design for a major wastewater treatment plant upgrade began in 2019, but it would be some years before construction would be completed. In the meantime, the City would need to manage influent BOD loads that were higher than the existing treatment plant capacity, and avoid effluent violations.
To address these challenges, the design team identified improvements that could be implemented quickly to improve WWTP performance, while simultaneously designing the full plant upgrade. Multiple options were considered, including process control improvements, additional aeration, and clarifier modifications. Due to budget constraints, the City selected a low-cost option: adding DO sensors in the oxidation ditch, an influent wastewater pH sensor, additional RAS flow meters, and an improved SCADA system. These interim improvements are integrated with the 30-year old control system. Though they represented a “short-term” fix, they were designed to be integrated effectively into the control system upgrade to be constructed with the full plant upgrade. DOE allowed the City to use design funds to construct the interim improvements, a major budget benefit.
These interim improvements allowed operators to quickly respond to changing influent wastewater characteristics, and more effectively manage secondary clarifiers. In addition, influent pH data has allowed the operators insight into industrial discharges, allowing the City to educate the industrial users on when their discharges were impacting the treatment process, resulting in fewer pH spikes. Process control was improved dramatically at a very low cost, reducing the burden on operators during the interim period before a major treatment plant upgrade.
|Date: Tuesday, 14/Sept/2021|
|8:00am - 9:30am||Session 12A: Collection & Conveyance|
8:00am - 8:45am
Pump Station Systems Design – How they can vary by Agency
Building on the popular 2019 presentation on pump system curve and pump selection, this presentation will delve into each pump station system, breaking down the wet wells, valving, power service, backup power, pump drives, level sensors, odor control, force mains, and pigging stations. This discussion will be supported by case studies, tying together the lessoned learned for design criteria, material or technology options, reliability and redundancy, permitting, and easement acquisition considerations. Understand Clark Regional Wastewater District and other local agency policy considerations on redundancy, odor control, force main pigging, or control strategy for facilities of varying size and complexity. Attendees will gain an understanding of fundamentals for pump station systems operations and design considerations. Case studies from local agency facilities will be presented to provide real world examples.
8:45am - 9:30am
How the COVID-19 Challenge Illuminated Opportunity Transformational Change With Collection System Maintenance
ADS Environmental Services, United States of America; email@example.com
COVID-19 (CV19) brought historic disruption to our lives and work. At the onset, wastewater collection systems operations faced exceptional maintenance and safety challenges.
Utilities implemented staff rotations attempting to limit person-to-person contact. Yet, these measures reduced maintenance capacity, affecting essential routines such as cleaning. Adding more stress, sewer-unfriendly objects started to appear in collection systems including “flushable wipes”, face masks and latex gloves. As a result, there was an increase of blockages, SSOs and fouled pumps.
Seeking relief, 83 US utilities leveraged existing flow and level monitoring networks adding new, predictive software for early stage blockage detection. This Internet of Things (IoT) architecture, captured and sent data to cloud-based software where, using machine learning-based analytics, early-stage blockages were identified predictively. Utilities gained weeks-worth of advanced notice enabling them to prioritize their limited O&M resources.
From April to October 2020, 53% of these utilities received at least one notification of a developing blockage. Additionally, none of the monitored sites had SSOs during that time.
Beyond SSO prevention, some utilities creatively applied this predictive IoT technology to determine when to clean. They hypothesized that scheduled cleaning, without the knowledge of actual site conditions, can result in cleaning already clean pipes. To gain site-condition information, utilities used IoT technology to determine when to clean. Three case studies demonstrate how IoT enabled transformational change in the face of sever pandemic-induced challenges. The studies document cleaning reductions of 80% to 87% and with zero SSOs.
These results strongly support the case for employing IoT-based cleaning protocols to fill O&M resource gaps, such as were caused by the pandemic. Furthermore, the results of these studies highlight the opportunity to meet challenges from any circumstance where O&M resources are constrained with the benefit being greater efficiency and lower organizational stress.