Integration of Asset Management with Real Time Simulation to Improve Reliability, Preventive and Corrective Maintenance and Reduce Life Cycle Cost in Wastewater Treatment for Reuse

An intelligent system has been developed and implemented at several BNR and ENR plants. It is based on an integrated approach to simulate processes and assets to improve or optimize operations, maintenance and asset management. It is also being used for Master Planning for Water and Biosolids Reuse.The IViewOps system incorporates an approach where the failure or aged condition of an individual asset such as a pump, blower or diffusers in a tank is incorporated into an intelligent asset hierarchy such that the daily online and readily available standby capacities are known for the system and used to make more informed operation, maintenance and optimization decisions. Second, it replicates the plant’s pumping, piping and valve configurations to accurately simulate hydraulic bottlenecks that arise when some tanks or clarifiers are taken out of service. Third, it incorporates physical, chemical and biochemical equations for the processes that occur in tanks and systems similar to process design models. The equations for process simulations conform to the IWA ASM2d model. The business risk and asset management attributes are as specified by International Infrastructure Management Manual (IIMM). Originally, the system was funded to optimize ENR plants, driven by a need identified by regulators to use the infrastructure assets more efficiently in winter and during wet weather. It has since been expanded such that the system assists with plant operations, provides intelligence to prioritize and improve preventive and corrective maintenance, and reduces the operating and life cycle cost of assets that are part of a system by identifying optimal setpoints. It can be used daily to advise and revise setpoints used for SCADA, in addition to a planning tool to improve the efficiency and timing of capital investments, and as a design tool.During its application at Upper Occoquan Service Authority plant (130,000 m3/d current flow) treating wastewater for reuse, and at the Westminster plant (20,000 m3/d current flow), the system has helped identify when nitrogen removal becomes a challenge in a particular part of the plant through daily computation of standby; it helped identify how to redistribute flows to manage nitrogen removal, when to take assets offline for maintenance and bring them online, and how to manage a construction and retrofit schedule. The changes to capacity of tanks in response to temperature, the changes to clarifier capacity in response to weekly changes in SVI, and the daily and weekly management of high nitrogen centrate recycled from anaerobic digesters are some of the parameters taken into account. It has been used to troubleshoot or optimize plants by managing flow routing and asset use, and to reduce energy use while meeting the permit. It is also used for operations and maintenance planning, for construction sequencing and for master planning.