For the last 30 years, there is no proper water treatment plant in the remote area due to the lack of the need of one (the natural water in the area as clean enough not to require treatment). Water is only disinfected before being distribute to the public.
With increasing number of human activity, coupled with the upstream area that have been converted into a recreation area, necessitates the need for a proper water treatment plant as the water at the intake is no longer clean as it used to be.
The LWUA (Local Water Utilities Authority) group monitors the situation closely and decides that a new water treatment plant should be built to continue supplying clean water as per WHO standards to the locals.
Therefore, a plan has been drafted out to build a brand new 6MLD plant capacity for the current need and the newly gazetted development in the area.
Requirements
- To design a state-of-the art water treatment plant in a remote area at Pandan district of Antique, Philippines with minimal maintenance.
- The plant controls has to be automated as the plant is needed to run 24 hours a day with no full-time operator at site.
- The plant operation has to be able to be monitored/controlled remotely as the area is remote and it will take time for operators to reach site in case of any issues at site.
- Plant running parameters a available at all times to monitor for any water input or output anomaly without being physically at site.
Solutions
- A new 6MLD UF plant is proposed, with two UF trains running 3MLD each.
- To fulfil the monitoring needs of the plant, the following instruments are installed:
- Incoming pH sensor
- Incoming turbidity sensor
- Incoming flow meter
- UF pressure transmitter
- UF ultrasonic level sensor
- UF output flow meter
- Treated pH sensor
- Treated chlorine sensor
- Treated turbidity sensor
- All water quality related instruments are installed in a sampling rack to allow easy access of all sensors in one place.
- To cope with varying demands of the plant, VFDs are used for the UF permeate pumps so that the plant capacity can be varied according to demand (based on current clearwell tank level).
- REMOX system which includes 4G connectivity is installed to allow the plant to be monitored and controlled from outside plant facility.
- Password access is enforced to allow only authorized personnel to login and monitor the plant.
- To facilitate the maintenance, the system also allows re-programming remotely from Malaysia without having to be physically at site in Philippines. Distance between site and the support team headquarters is 2,500km. Therefore, remote maintenance is a must for such system to allow short turn-around time during plant fault.
- To ensure operators or management get the best heads-up during plant fault, a SMS alarm messaging system is provided. All critical alarms occurred at plant will be relayed to the operator or management at real-time through SMS service.
- SMS reporting is also provided to allow the 4G modem to send hourly status report of the plant to intended operator / management personnel. Up to 10 numbers can be programmed into the system.
- Data logging function is installed to ensure all plant operating parameters and alarm events are logged properly to future review or post-mortem purposes.
- On the mechanical side, fully automated periodic backwash and CEB ensures the plant running in pristine condition for as long as possible before a scheduled CIP which requires operator intervention.
Conclusions
- The system delivered is able to run in automatic mode, lessening the amount of manpower needed.
- The enhancement of remote monitor and control function drastically helped the team to troubleshoot and resolve any issue easily without being physically on-site.
- SMS function helped the operator to be alerted within short period after an alarm has occurred and lower the amount of downtime due to fault.
- However, the issue of power stability have been overlooked during the initial design causing multiple failure of devices due to frequent brown-out, black-out and also voltage surge. A voltage protection device have been installed after commissioning to arrest the issue of the voltage and trip the plant intentionally to protect all equipment in the event of an unstable voltage input.
- Areas to be improved :
- Critical equipment related to REMOX system to be plugged to a UPS system so that it can function and send messages in the event of plant trip
- Voltage protection device, lightning surge protection device to be made standard in the future to prevent failure due to voltage issue / lightning strike
