Testech VOC04 – Real Time VOC Remote Monitoring system is a intelligent fully integrated system that has field proven long term reliability and low cost of maintenance in monitoring VOC in Sewer manhole. Measuring VOC in Sewer is a tough and harsh environment saturated with high humidity and contamination particles especially in waste treatment plant effluent discharge outlet. Testech specialize in designing VOC Gas Sampling and Measurement System as well as other water qualities and weather monitoring system deployed in South East Asia countries. VOC04 has been proven to be able to provide accurate 98% to 100% of calibrated reading over a minimal of 2 months continuous operation in a very humid environment and does not provide false positive alarm. The system measures the VOC in the sewer with automatic zeroing, cleaning and able to send VOC Alert with no false alarm. The system has been successfully deployed in Singapore and we welcome any overseas enquirers to purchase subsystem for OEM integration .


Model : VOC04


VOC Meter:
Range: 0 – 1000 ppm (can be set to 0 -100ppm, 0 – 250ppm, 0 – 500ppm)

Testech custom design PD1000 designed for sewer measurement.

Built in Temperature/Humidity Sensor.

Proprietary mechanism solve contamination and condensation at PID lamp.

Fully digital interface and control via RS485.

Full diagnostic information of the PID sensor and pump condition.

Ease of quick bump check capabilities.

Designed for interface with Testech VOC04 RTU and gas conditioning sub system.

Response Rate: 15secs

Pump Flow Rate: Up to 800cc/minute.

Long Term Proven Reliability:
Maintain +/- 5ppm of calibrated range measurement in Last IC under waste Treatment environment.

Power Input:
External 240VAC +/- 20%

Battery Backup:
Up to 6 hours.

External Serial Interface
RS232C or RS485 for Sensor or Meter Interfacing such as PLCs, Recorder, Gas Sensing Sampler


Weather Proof:
IP66 insects ingress free.

The system has been designed from the ground up for monitoring VOC in sewer and dealing with the issue that plague standard off fixed PID VOC Sensor that was not design for use in sewer environment. Simply just adding a Gas dehumidifier in the gas path will reduce but not eliminate the problem, neither does claim of patented humidity compensation.

This VOC monitoring system was designed after years of operating in sewer measurement condition and has resolve the issues of contamination and dead or low reading associated with normal simple continuous VOC Measurement system.

VOC04 VOC Trend with intelligent control algorithm

Below is trend of VOC off a waste water sewage with 100% saturating humidity and contamination particle. Testech VOC04 is able to withstand such harsh measurement environment due to our propreity gas sampling and control algorithm, providing VOC alert without false alarm

VOC04 is fully closed loop digital control for every aspect of the sampling, purging, cleaning, measurement, post measurement, post purging, alarm tracking cycle. This is possible as the VOC Meter was co develop by Testech allowing the RTU to have full digital control, access to operating and measurement parameters at the core firmware level. The VOC Meter operation is under the full control of the RTU. The Entire system is a fully tight controlled operational with every aspect of the system cycle of operation under the supervision and control of the custom design firmware on the PM052 RTU.

VOC Alert Remote Monitoring System, delpoyed in Singapore public sewer

The PID1000 has built in Sampling Pump, purging valve and the pump can be set to run at maximum of 800 cc/minutes which is adjustable.

The PID1000 can be calibrate to 0 – 50ppm, 0 – 100ppm, 0 – 250ppm, 0 – 500ppm and 0 – 1000ppm

Long Life Pump condition and Lamp for 3-5 years.

Summary Of Features

Fast gas measurement response rate of 15secs (0 – 100ppm)

Full digital control of the entire system for the entire phase of gas preparation, sampling, measurement, post measurement, purging, cleaning phase. The VOC, Temperature, RH parameter are digital acquire without using any analog output.

Built in High capacity 1L/minutes Dehumidifier maintain RH to no more than 25% RH.

VOC Meter has built in temperature and humidity sensor and voc measurement compensation.

Complete system health status is capture by RTU and allows user to know if the system health state and report during health check or user query.

Eliminate Gas sampling path water condensation along the tubing due to intelligent control of gas sampling and purging operation.

Aqueous sample fill detector indicate of the water sample are actually capture in the bottle.

Low cost of hardware maintenance due to low wear and tear unlike continuous measurement system (which are lower cost)

No False Alarm. Alarm and VOC measurement value and validity are continuously tracked by RTU to ensure there is no false alarm. Ambient VOC is always track, along with VOC measurement. Duration of each stage of alarm are continously capture and reported

Fully digital measurement eliminate analog inaccuracies of analog conversion

Full diagnostic of the sensors pump, sensors condition as well as subsystems are detected and report digitally.

Optimized control and software reduce maintenance and sensor degradation.

Send SMS Alert for corrective action.

Battery backup safeguard against power failures.

Can support optionally Tscada or ClearScada as well as any third party SCADA.

Optional isolated 4-20mA output of sampled measurement interface to customer SCADA.

Solid State Gas Dehumidifier maintain Gas Humidity < 40% even in a 100% saturated Sewer humidity condition.

Beacon and Siren Alarm

External Relay output to support pan stop and customer corrective action system.

Power Input:
240VAC +/- 20%,


Weather Proof:
IP66 insects ingress free.


Last IC : Trade Effluent control and measurement.


For large scale remote monitoring, VOC04 can be remotely monitor and remotely triggered using the TSCADA and sending alarm to users.
Contact us for this options.

Contact us for free consultation for your custom projects.

Link to TSCADA