Piscataway WRRF Bioenergy - Owner and PDB Collaborative Sampling during Startup and the Transition into Operational Sampling

The Piscataway WRRF Bioenergy Project (Project) is the largest biosolids project WSSC (Owner) has completed, and it includes several innovative technologies and process areas for operations: anaerobic digestion, a thermal hydrolysis process (THP), combined heat and power (engine-generators and boilers), gas upgrading and flaring, and sidestream treatment. Completing an integrated start-up of complex facilities brings with it many challenges, requiring a collaborative approach to drive a successful overall commissioning process. The biggest challenge is maintaining the biological health of the anaerobic digesters and sidestream treatment processes. The health of these facilities dictates the rate at which solids can be processed through the system. To gage the health of these facilities, a robust sampling and analysis plan was needed. This paper and presentation will lay out the key steps the Owner and Progressive Design-Builder (PDB) took to develop and execute the sampling and analysis plan to drive successful start-up. A detailed sampling and analysis plan was developed prior to startup, with the goal of providing accurate and reliable data to support decision-making during the startup process. The project team was tasked with reviewing data daily to decide how to ramp up the process while maintaining digester and sidestream health. Several key factors and lessons were learned in various aspects of sampling and analysis during the start-up of the new thermal hydrolysis process (THP), digestion, dewatering, and other facilities. These included: - Defining the roles and responsibilities, including who is responsible for training and analysis - Upfront definition of the analytes, sampling methods, and frequency of sampling - Need for effective collaboration between an Owner and PDB team - Developing procedures from transitioning from startup sampling to daily operational sampling. Determining who should perform the sampling is a significant decision. The Project contract included language assigning sampling and analysis responsibility to the Owner. With this contract responsibility, the WSSC Water Consolidated Laboratory's ability to perform and oversee sampling activities was essential. This included evaluating their technical expertise, available resources, and understanding of regulatory requirements. Assigning responsibility to Owner teams may offer better control and understanding of project specifics, while engaging external contractors can provide specialized expertise and efficiency. Defining clear criteria for the required samples was fundamental. This involved identifying the specific analytes, sampling methods, and the frequency of sampling. Establishing these criteria helped maintain consistency and reliability in the data collected. The PDB team worked to develop and format, with Owner collaboration, an online shared document. Figure 1 provides an example of the Digester Solids and Biogas Sampling matrix that was used throughout the startup. Maintaining this shared document for collected data provided transparency and accessibility. This document was updated daily and accessible to all relevant stakeholders. It facilitated collaboration, reduced the risk of data loss, and provided everyone with the most current information. For Digester health critical criteria was identified and guardrails established for FOS, TAC, FOS/TAC ratio (a ratio that measures the levels of volatile fatty acids to total alkalinity), pH, Ammonia, and digester temperature. As an example, a sudden drop in pH due to volatile fatty acid buildup could cause the digesters to sour. The Owners daily sampling efforts allowed the Project Team to monitor these critical criteria and make quick decisions as they arose. Several parameters were monitored and graphed to monitor start-up performance and digester health, as shown in Figures 2 and 3 below. Additional sampling methods and results will be presented in the manuscript and presentation. Executing the startup sampling included two main components: daily operational sampling for process health monitoring and performance guarantee sampling and analysis. The Owner's operations staff conducted onsite sampling, with performance guarantees analyzed by certified lab technicians. Additional quality assurance (QA) on operator-taken samples was vital to maintain data integrity. QA processes included regular audits, cross-checks, and validation of sampling methods. This provided confidence that the samples collected were representative and reliable. Different process areas (Dewatering, THP, Sidestream Treatment, etc.) required individual analytes and sampling methods, so training for sample collection was crucial to ensure accuracy and consistency. This training covered the proper use of equipment, sample handling, and documentation procedures. Third-party analysis verification added an extra layer of assurance to the sampling process. Independent verification helped identify any discrepancies and provided confidence that the data met the required standards. It also provided an unbiased assessment of the sampling and analysis process. Transitioning from the commissioning of the Bioenergy Facility to normal operations occurred over the final months of the construction project. Another benefit of implementing a startup sampling plan and having the Owner perform this sampling was a more seamless transition into normal operations. The extensive sampling during startup is planned to be pared down and the data workbook kept as an operational log for Owner operations and engineering staff to make informed decisions for daily operations into the future. Overall effective project sampling and analysis during startup involved a combination of strategic planning, technical expertise, and collaboration. By understanding the lessons learned in these areas, project teams can enhance the accuracy and reliability of their data, leading to better decision-making, successful project outcomes, and preparing WSSC Water Operations for successful operations and data management into the future.