Three weeks after the major toxic discharge of a chemical that disrupted the sewage treatment plant at Echten, it is still not clear what substance was involved and who caused the problem.
However, the Drents Overijsselse Delta (WDODelta) water board has been carrying out additional checks since the extensive pollution detected on 10 February. “Our people monitor the sewage water that comes in for purification on a daily basis,” says spokesman Herald van Gerner. “We are on top of it.”
Important questions
This measure will remain in force for the time being. Meanwhile, after three weeks of research, some important questions remain unanswered. Who discharged what into the sewer at the beginning of February? And was it intentional or not?
,,We don’t know yet”, Van Gerner admits. According to him, the water board sent contaminated water samples to the Aqualysis water laboratory in Zwolle immediately after the incident.
‘Complex’
“The investigation is continuing,” the spokesman said. “Of course we would like to know which substance or substances have been discharged and who is responsible for this. But it’s complex.”
Initially, a substance was thought to be related to a pesticide: a chemical agent used to control weeds, fungi, insects or vermin. But according to Van Gerner, that analysis turned out to be incorrect.
Drug lab chemicals?
The water board also does not recognize that the water board “takes serious account” of the discharge of chemicals by a drug lab, as sources claim to this newspaper. “We are not aware of that,” says the spokesperson for the WDODelta water board.
Nationally, water boards are increasingly suffering from large drug discharges into the sewers or surface water. Especially in Brabant. The Netherlands Forensic Institute (NFI) sees an increase in the number of discharges at drug production locations. Various water boards in the country are experimenting with technical aids to detect drug chemicals more quickly, for example.
Water board WDODelta, which manages sixteen treatment plants, sometimes finds things that do not belong in the sewer, but not in the nature and scope as on February 10 of this year.
Bacteria
Then part of the treatment plant had to be shut down, because some of the bacteria that clean the water were killed by the unknown chemical(s). As a result, the sewage water was insufficiently (biologically) treated.
The water board removed the dead bacteria and replaced them with healthy ones from the Smilde and Dieverbrug sewage treatment plants. This solved the problem after more than a week. The costs amounted to approximately 15,000 euros.
According to WDODelta, the outage had no consequences for residents in the municipalities of Hoogeveen and De Wolden. They could simply use the toilet, bathroom, sink and washing machine.
Safety
The extra checks at the Echten sewage treatment plant that have been carried out since the incident are intended to guarantee the safety of the surface water. In the installation, polluted waste water from households and companies is treated. This cannot simply be discharged into ditches, lakes and other bodies of water because it endangers the health of people, animals and nature.