Integrating Medium Pressure UV with a Sequential Batch Reactor (SBR)

In the ever-evolving landscape of wastewater treatment, innovation continues to drive improvement.  Among the arsenal of technologies available, the integration of Medium Pressure UV (MPUV) systems with Sequential Batch Reactor (SBR) pre-treatment stands out as a promising solution for tackling the challenges of wastewater disinfection.

MPUV has commonly been applied in conjunction with SBRs, but there still exists a perceived mismatch between the operational characteristics of both technologies. SBRs operate in cyclic sequences of fill, react, settle, and discharge phases, resulting in frequent on/off cycles.  Conversely, MPUV systems prefer to operate in relatively stable operating conditions, including warm-up and cool-down periods to achieve optimal performance. This misalignment has led many wastewater treatment plants to miss out on the benefits of MPUV, mainly its small footprint, ease of installation, reduced maintenance requirements and low man-power needs.

The key challenges in integrating MPUV with an SBR lie in managing the on/off cycles of the SBR and the potential heat build-up of the MPUV, to ensure consistent UV exposure while minimizing energy consumption and operational costs.

Solutions for synchronizing MPUV and SBRs.

To address this challenge, MPUV suppliers have developed solutions tailored to the specific requirements of the MPUV-SBR integration.

1. Advanced Control Algorithms – MPUV suppliers can collaborate with the SBR supplier and plant integrator to develop control algorithms. These algorithms are tailored to synchronize the MPUV with the SBR. By doing so, the UV system can modulate lamp power during SBR “relax mode”, mitigating heat buildup in the MPUV and eliminating the need for frequent on/off cycles associated with SBR operation.
2. Bleed Valve Integration – introducing a bleed valve into the UV process, coupled with the temperature switch on the UV system, offers a targeted solution to manage heat generation. When the temperature switch detects a threshold indicative of potential heat accumulation, it triggers the opening of the bleed valve. This action allows fresh water to enter the MPUV chamber, effectively dissipating excess heat and maintaining optimal operational conditions.
3. Colling Loop Implementation – The cooling loop method stands as the preferred approach, widely adopted by wastewater treatment facilities. This method involves the installation of a closed-loop system that facilitates the circulation of water. Water circulation serves the primary purpose of dissipating the heat generated by MPUV when the SBR is in relaxing mode. By implementing this closed-loop configuration, the need for warm-up and cool-down periods is eliminated, ensuring continuous and uninterrupted operation of the MPUV system.

SBR Case Study #1 – Medium Pressure Retrofit into SBR

AT a 5 MGD WWTP located in Pennsylvania, an MPUV system was implemented as part of a retrofit with an existing SBR.  The integration was achieved through successful planning and collaboration between the client, integrator and Nuvonic.

From the outset, close communication and coordination between all stakeholders ensured transparency and alignment of objectives throughout the integration process. 

A key feature of the integrated system is its optimized operational strategy, designed to maximize energy efficiency and performance while minimizing downtime.  The MPUV system is configured to operate continuously, with UV lamps only being turned off during scheduled maintenance, typically once per year. During periods of SBR “relax mode,” the MPUV system seamlessly transitions to an “Energy Efficient Mode.” Where poser consumption is reduced to a minimum.  By eliminating on/off cycles, the system ensures consistent disinfection performance while conserving energy and reducing operational costs.

At this 5 MGD plant in Indiana, an MPUV was installed on an SBR as part of a retrofit. The MPUV is integrated into the plant controls, ensuring the SBR and MPUV work together.  Up front meetings with the client and integrator ensured transparency in the process and allowed for a seamless integration of the two technologies.  The UV is only turned off for maintenance, which is once per year otherwise, during the SBR relax mode, the UV system power consumption drops down to an “Energy Efficient Mode” ensuring minimal power is consumed, on/off cycles are eliminated, and the system stands ready to meet performance requirements when the decant is over.

SBR Case Study #2 – Closed-Loop Integration in SBR Wastewater Treatment

In 2021, an Oklahoma WWTP commissioned their SBR plant, incorporating MPUV and a closed-loop recirculating system as part of their innovative approach.  The primary objective of this system was to mitigate the challenges associated with the on/off cycling of the MPUV system typically encountered during SBR decanting.

With the WWTP operating at a frequency of 10 decants per 24 hours, ensuring uninterrupted UV disinfecting during these cycles was paramount to achieving optimal treatment efficacy. By implementing the closed-loop recirculation system, heat generated during the SBR decants is effectively dissipated, thereby eliminating the need for MPUV system shutdowns or power reductions.

While the initial investment in designing and implementing the closed-loop recirculation system added to the capital and operational costs, the total cost of ownership (TOC) was still significantly lower for the plant to install a MPUV system versus other UV system configurations.

SBR Case Study #3 – Innovative Control Algorithm for Effective Heat Dissipation

In Colorado, a forward-thinking WWTP embarked on the optimization of their SBR plant to meet the unique demands of their operation.

With a decant frequency of six times in 24-hours the treated wastewater meets reuse standards and is provided for golf course irrigation.

Despite the absence of a closed loop cooling system, the implementation of a controls algorithm and planning between the plant controls integrator and Nuvonic, ensures the synchronization between the MPUV and the SBR.

The plant also decided to install UltraWipe, the chemical wiping system offered by Nuvonic.  Hardness, Manganese and Ferric are commonly found in wastewater and can precipitate out of solution and adhere to the quartz sleeves.  This can lead to a reduction in UVC output, low performance (dose), alarms, late-night call outs, failed permits, and the need for frequent hand cleaning of quartz sleeves.

UltraWipe uses citric acid as part of the automatic wiping system to keep compounds from adhering to the quartz sleeves, reducing, or possibly eliminating the need for hand cleaning.

Nuvonic for Integrating SBRs and MPUV

One of the standout features of integrating a medium pressure UV system with a SBR pre-treatment is the ease of installation. In most cases the MPUV can be flanged directly to the SBR tank, thus eliminating the complexities of additional valves and fittings.  This streamlined setup significantly reduces downtime for retrofits and labor costs, making it an attractive option for facilities looking to enhance their water treatment capabilities efficiently. The UV system’s compatibility with existing SBR configurations ensures a seamless integration, minimizing the need for extensive modifications or specialized equipment.

The integration of Medium Pressure UV with Sequential Batch Reactors represents a significant advancement in wastewater treatment technology for those that were not aware this combination existed. The pairing offers the benefits that an SBR brings while also the small footprint, minimal maintenance, and low resource requirements of Medium Pressure UV. The integration requires careful planning, and Nuvonic and our global network of partners are experienced at supporting the site.

As wastewater treatment facilities strive to meet increasingly stringent regulatory standards and sustainability goals, the integration of MPUV with an SBR is emerging as compelling solution for achieving superior water quality, protecting public heath, and meeting the operational goals of WWTPs.

If you need Nuvonic to help coordinate the right process for using MPUV and an SBR, reach out to our team of experts to find the right option for your applications and budget.