SINGAPORE: A swim school in Jurong East has been fined S$6,500 for illegally discarding chlorine powder into public sewers, PUB said on Monday (Dec 6).
On Mar 5, an employee of Happy Fish Swim School dumped about 45kg of calcium hypochlorite into the sewers at the swim school at Jurong Gateway Road and used a fire hose to flush water down the sewer, said PUB.
Authorities were alerted to the incident when alarmed residents in the area reported hearing a loud explosive sound, said the national water agency.
Happy Fish Swim School founder Tan Jian Yong previously said that there were no students on the premises when the incident happened, and that no injuries were reported.
He said the school hired a waste management company after noticing a strong smell from the chlorine drum, which had come into contact with moist air.
An employee, a maintenance keeper, had "mistaken the intention and took the initiative to discard the chlorine powder into the sewage without knowing that it will cause issues", said Mr Tan.
PUB said at the time that there was no impact to the sewerage system or quality of used water, which is taken to its reclamation plants for treatment.
On Monday, PUB explained that calcium hypochlorite, commonly used for pool sanitisation and maintenance, is a highly reactive and corrosive chemical.
"The improper disposal of calcium hypochlorite into the sewers exposed it to organic matter present in used water," said the agency.
"This caused a chemical reaction that created a loud explosive sound and released a large volume of chlorine gas into the sewers."
PUB confirmed that the incident did not cause any injuries or damage to the sewerage system.
It added that investigations showed Happy Fish Swim School did not have written approval to discharge trade effluent into the public sewers, but did so instead of engaging a toxic industrial waste collector.
Illegal disposal of hazardous substances into the sewers is an offence punishable under the Sewerage and Drainage Act. Happy Fish Swim School is a first-time offender, said PUB.
The agency added that it also found several safety lapses in the use, storage and disposal of chemicals on the school’s premises.
These included a lack of secure facilities for proper storage of chemical products, no training or documentation provided to employees assigned to handle hazardous chemicals, and lack of monitoring systems to prevent and deter unauthorised access to stored chemical supplies.
"The disposal of hazardous substances into the sewers is an irresponsible act that can adversely affect the operational integrity of the public sewerage system, disrupt the used water treatment process, and severely endanger the health and safety of the workers maintaining the system," said Maurice Neo, director of PUB's water reclamation network.
"Companies are responsible for ensuring that all trade effluent is adequately treated to comply with discharge requirements before being disposed into the sewers, and that hazardous substances such as used oil, spent solvents and leftover chemicals are properly segregated and collected by the appropriate licenced waste collectors."
Following this incident, PUB said authorities issued a joint circular to all swimming pool operators and owners on the safe use and disposal of chlorine-containing chemicals for disinfection.
Under the Sewerage and Drainage Act, first-time offenders who illegally dispose of hazardous substances may be jailed up to 12 months, fined up to S$50,000 or both.