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Volatile Organic Compound (VOC) Monitoring System

Used water is a precious resource in Singapore, and the integrity of our public sewerage system is critical to PUB's water reclamation process. Every discharge must meet the prescribed quality requirements. Companies are prohibited from illegally discharging trade effluent containing chemical substances that exceed the permitted limits into the public sewerage system. Excessive levels of these hazardous substances in wastewater can disrupt the treatment processes in PUB's water treatment facilities and affect the quality of the feedstock for NEWater production.

Businesses and industries must take responsibility to ensure that their trade effluent meets the discharge standards of PUB to keep Singapore's water resources and wastewater network safe. To monitor VOCs in commercial wastewater, PUB may require that a VOC monitoring system be installed at the last IC of trade premises.

At Seraya Engineering, we have designed and manufactured the Model 862 Smart VOC monitoring system in compliance with the Code of Practise on Sewerage and Sanitary Works. The PID meter that we have incorporated into our system is approved by the authority and qualified in real-time monitoring of the VOC presences in the sewage application. The Model 862 Smart VOC monitoring system is designed to be able to operate reliably with minimal field service maintenance and calibration.


The VOC meter works on the principle of photo-ionisation detection (PID) and measures VOC readings between 0ppm and 1000ppm, which corresponds to isobutylene. The PID sensor, housed in an explosion-proof enclosure, is equipped with a local digital display of the gas concentration. The analogue output ranges from 4 to 20 mA, which corresponds to 0 to 1,000 ppm isobutylene. The PID sensor is equipped with a long-life 10.6 eV ultraviolet lamp.

The PID sensor may give false-positive readings when exposed to water vapour. Rain can also affect performance. High humidity can cause fogging of the lamp and reduced sensitivity. This can be significant if the moisture content of the sample gas is high.

Therefore, the dehumidifier in the VOC monitoring system plays the important function of removing moisture from the air sample before it enters the PID sensor. Our dehumidifier has a built-in temperature controller and can lower the dew point from 1°C to 3°C. As a result, it can remove much of the moisture from the air sample before it enters the PID sensor.

Range of PID Meters

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Seraya Engineering Pte Ltd

2 Jurong East Street 21

#04-23, IMM Building

Singapore 609601

Tel: +65 6252 1737

Installation & Deployment

Calibration Services

On-site Commissioning Services

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