Meeting with MBR OEM Team & OWATCO regarding: PURON® MBR System Maintenance
Date: February 21, 2024
Location: Muscat Bay Office
Participants: OWATCO Company, Muscat Bay Management - OEM MBR team
Time: 12:30 PM - 02:00 PM
Subject: Operational Excellence and MBR System Refurbishment Initiative
Next Meeting: February 27, 2024, at Muscat Bay Office
OWATCO team,
Referring to our meeting yesterday with OEM Team attendance, our discussions was about the MBR of the Muscat Bay STP plant, which uses the PURON® MBR system for wastewater treatment. As Earlier agreed about the conducting the inspection for the membrane and we would like to ensure that you to perform the tasks with professionalism and care.
We have had some issues with previous same works, who caused a shutdown of our STP plant. We hope that you will avoid such mistakes and follow the OEM manual and the best practices for the PURON® MBR system maintenance.
In this letter, we will provide you with some instructions, advice, and evaluation on how to perform the maintenance tasks for the PURON® MBR system effectively and efficiently. We will also provide you with some technical details and parameters for the PURON® MBR system maintenance, as well as some reminders and tips.
Expect
OWATCO to prepare a comprehensive and detailed maintenance plan for the PURON® MBR system, which covers the following aspects:
- Daily operations and monitoring
- Weekly maintenance
- Monthly maintenance
- Quarterly maintenance
- Bi-annual maintenance
- Annual maintenance
You can find the maintenance plan attached into previous letter. You should follow the maintenance plan strictly and perform the tasks according to the instructions and parameters provided. This will ensure the optimal performance and longevity of the PURON® MBR system, as well as the compliance with the safety and environmental standards.
Recommendations for PURON® MBR system:
- Monitor the system performance and optimize the maintenance strategies: OWATCO to monitor the key parameters of the system on a daily basis, such as
- Permeate flow rate,
- Trans-membrane pressure (TMP),
- Aeration flow rate,
- MLSS concentration,
- Maintain the safety procedures and record keeping as should adhere to the OEM and industry-standard safety protocols for chemical handling, maintenance operations, and emergency responses. You should use appropriate personal protective equipment (PPE) and follow the Material Safety Data Sheets (MSDS) instructions. You should also document all the maintenance activities, system performance data, and cleaning efficacy in log books. You should ensure that the log books are organized and readily accessible for review and optimization purposes.
- Provide comprehensive training for your staff on the maintenance procedures, emphasizing the significance of each task and promoting familiarity with the OEM documentation and safety guidelines. You should also familiarize yourself with the OEM manual and the best practices for the PURON® MBR system maintenance, and consult them whenever you have any questions or concerns.
OWATCO also, to conduct visual inspections, chemical inventory checks, backflush efficiency checks, and integrity tests on a regular basis. These will help you identify any issues or deviations from the OEM benchmarks and adjust the operations and maintenance practices accordingly. You should also review the system performance data and the cleaning efficacy periodically and optimize the maintenance strategies based on the analysis.
Evaluation
We will evaluate your performance and the quality of your work based on the following criteria:
- System performance and effluent quality: We'll gauge system performance and effluent quality against OEM benchmarks and regulatory standards, comparing actual to expected values to assess deviation and improvement. Influences like operational conditions, environmental factors, and maintenance practices will be considered.
- Maintenance frequency and effectiveness: We'll oversee the frequency and efficiency of your maintenance tasks, including MC, RC, system monitoring, and membrane replacement. We'll ensure adherence to the maintenance schedule, checklist, and guidelines. We'll also evaluate
- Safety compliance and record keeping:We'll verify your adherence to safety procedures for chemical handling, maintenance, and emergency responses, along with the documentation of maintenance activities, system performance, and cleaning efficacy. The accuracy and completeness of log book entries will be reviewed.
We will provide you with regular feedback and suggestions based on our evaluation. We will also conduct periodic audits and inspections to ensure the quality and reliability of your work.
Technical Details and Parameters
We have also prepared some technical details and parameters for the PURON® MBR system maintenance, based on the OEM manual and the industry standards. Here are some of the main points that we would like you to know and follow:
- Membrane Details: The PURON® MBR system uses hollow fiber, braided membranes with outside-in filtration. The membranes are made of proprietary PVDF, which is known for its strength, chemical resistance, and longevity. The nominal pore size is 0.03 µm, which ensures high-quality effluent by effectively removing solids, bacteria, and viruses. The system is designed to operate within a temperature range of 41-104°F (5-40°C), accommodating various environmental conditions. The PURON® MBR modules comply with the California Water Recycling Criteria (Title 22), ensuring the produced effluent meets stringent quality standards.
- Maintenance Cleaning (MC) and Recovery Cleaning (RC): MC can be activated based on a timer or manually by the operator, using sodium hypochlorite and citric acid as cleaning agents. The MC procedure typically lasts for 30-45 minutes and can vary based on system requirements. RC is a more intensive procedure that requires submerging the membranes in a chemical solution for 6-12 hours. The RC procedure should be performed bi-annually or as-needed, depending on the TMP and permeate quality. The cleaning agents, concentrations, contact times, and solution conditions for MC and RC are specified in the OEM manual and the maintenance plan.
- System Monitoring: The system monitoring tasks include measuring and recording the permeate flow rate, TMP, aeration flow rate, and MLSS concentration on a daily basis, conducting visual inspections, chemical inventory checks, and backflush efficiency checks on a weekly basis, and performing integrity tests on a quarterly basis. The OEM manual and the maintenance plan provide the ranges and values for the key parameters, as well as the instructions and methods for the monitoring tasks.
- Membrane Replacement: The membrane replacement plan is based on the performance review and the expected membrane lifespan. The OEM manual and the maintenance plan provide the criteria and procedures for membrane replacement, as well as the safety precautions and post-replacement checks.
Reminders and Tips
- Follow the control philosophy for system startup: Adhere to the control philosophy outlined in the OEM manual for transitioning the system through Standby Mode > Back Flush Mode > Process Mode. This includes handling the deaeration and filtration process flow as per the specific programming for your system.
- Allow a stabilization period after RC: After RC, allow a stabilization period of 15-30 minutes before applying maximum fluxes to cleaned trains to prevent stress on the membranes. Evaluate the RC data to determine the effectiveness of the cleaning and the condition of the membrane. Adjust future cleaning strategies based on this analysis.
- Apply backflush pressures no greater than 600 mbar across the membrane: Do not exceed the specified pressure during backflushing to avoid damaging the membrane integrity. Follow the OEM guidance on optimizing the cleaning parameters and maintaining a proactive approach to membrane system management.
- Clean the membrane tank after maintenance: Manually remove all loose material and vacuum to remove fine material and dust from the tank. Carefully hose down residual sludge from tank walls without directly hitting the membrane surfaces to avoid damage.
Abdulrahim AL Balushi
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