Two toxic industrial waste collectors, Chem-Solv Technologies and NSL OilChem Logistics, as well as a membrane manufacturing firm Century Water Systems and Technologies, have been convicted and fined in court for discharging toxic and hazardous substances into the public sewers. This is an offence that risks causing harm to the workers maintaining the public sewerage system, damaging the country’s used water treatment facilities, and polluting the environment.
The three companies were prosecuted under the sewerage and drainage act and sewerage and drainage, trade effluent regulations. Chem-Solv Technologies and NSL OilChem Logistics were both charged and prosecuted in court in November 2022. The former was fined S$8,500 and was ordered to install additional monitoring sensors on its premises, while the latter was fined S$13,000. Century Water Systems and Technologies was charged in February 2023, and was fined S$3,300.
Detecting illegal discharge in public sewers
From May-September 2021, National water agency PUB’s online sensors detected abnormally high levels of prohibited volatile organic compounds in the used water discharged from factories in the Pioneer Sector area. On 6 Sep 2021, PUB officers carried out a surprise inspection at Chem-Solv Technologies’ premises and found that greenish effluent was being discharged into the public sewers. Tests confirmed that the discharged effluent contained eight different types of prohibited organic compounds. The concentration level of one of these organic compounds, toluene — an organic compound used as an industrial feedstock and as a solvent — was dangerously high and could have posed a fire or explosion hazard in the public sewerage system.
Between December 2021 and January 2022, PUB’s regular sampling regime detected abnormally high levels of regulated substances such as heavy metals and boron on several occasions in the public sewers located in the Tuas area. PUB traced these readings to NSL OilChem Logistics’ premises. On 25 Jan 2022 and 1 Feb 2022, PUB collected samples of the company’s trade effluent. Tests confirmed the presence of three heavy metals and boron beyond permissible levels.
A routine inspection at Century Water Systems and Technologies’ premises on 20 May 2022 found that the company was discharging non-compliant trade effluent containing high concentrations of dimethylacetamide, instead of engaging a licensed toxic industrial waste collector for proper disposal. Dimethylacetamide is a semi-volatile organic compound commonly used in industrial solvents. Excessively high concentrations of the compound have been known to cause disruptions to the NEWater production process.
PUB monitors more than 5,000 companies annually for trade effluent discharge containing regulated substances into the public sewers. There is a programme in place to detect discharges of non-compliant trade effluent, which consists of real-time online sensors in the public sewerage system, routine inspection of premises, as well as a regular sampling analysis regime to monitor the quality of used water within the public sewers.
“Used water is a resource that is treated and recycled to produce NEWater, and our public sewerage system plays a role in the reclamation process. The illegal discharge of non-compliant trade effluent into our public sewers can cause environmental pollution, disrupt the operations at our used water treatment plans, and endanger the health and safety of workers. To ensure that our operations, workers and the environment are fully protected, we will not hesitate to take enforcement action against any companies caught breaking the law,” said Maurice Neo, director of PUB’s water reclamation network department.
Under the regulations, the penalty for discharging hazardous substances is a fine of up to S$15,000 or imprisonment for up to three months, or both. Under the sewerage and drainage act, the penalty for the illegal disposal of hazardous substances that may pose danger to the safety and health of people or any part of any public sewerage system, is a fine of up to S$50,000 or imprisonment for up to 12 months upon first conviction, and up to S$100,000 and/ or imprisonment up to 12 months for repeat offenders. As part of an enhanced enforcement regime, PUB may also revoke approval for trade effluent discharge, or issue stop-order notices to prevent errant companies from discharging non-compliant trade effluent into the public sewers. Such orders will only be lifted when the companies implement appropriate remedial measures to ensure that the quality of their trade effluent complies with the law.
With its surveillance and enforcement regime, PUB has seen a decrease in the number of illegal trade effluent discharge offences in the past decade. Going forward, enforcement levers will continue to be strengthened where needed to deter such offences.