The warning comes as the regulator, the Industrial Works Department, insisted it has done its best to control and monitor wastewater discharge.

The UN’s World Water Day was marked on Wednesday under this year’s theme of “water and wastewater”.

Thailand faces several problems related to wastewater – a fact highlighted in October by a massive die-off of giant freshwater stingrays in the Mae Klong River because of poor water quality due to upstream wastewater discharge.

The executive director of Ecological Alert and Recovery Thailand (Earth), Penchom Saetang, said the wastewater problem in Thailand remains severe and immediate legal solutions are needed to tackle this chronic environmental problem.

“The Pollution Control Department [PCD] disclosed in the annual pollution report for Thailand for 2016 earlier this year that for the overview of water pollution in Thailand last year, the situation was slightly improved. But from my view as a public sector watchdog, I argue that our water pollution problem still remains unacceptable,” Penchom said.

“This is because we still face severe water pollution problems in many river basins especially the Chao Phraya, Tha Chin, and Rayong River basins, which are the main industrial bases of the country.”

She said that according to the PCD report, the agricultural sector is the largest pollutant as the country’s farms discharged up to 39 million cubic metres of wastewater per day last year, while the industrial sector ranked second after discharging 17.8 million cubic metres per day. The residential sector ranked third with 9.6 million cubic metres per day.

She said the efficiency of wastewater treatment processes in the residential sector were only 18 per cent effective, while only 52 per cent of wastewater was treated.

“This is the result of weak law enforcement and poor monitoring systems, as our environmental laws require only a few water pollution indicators to be monitored, while many dangerous substances, such as heavy metals, are left largely unnoticed in many water consumption sources,” she said.

“Therefore, Thailand should have the Pollutant Release and Transfer Registers law, which requires the operators to identify all pollutants that they release to the outside environment. With this law we can pinpoint who is the big pollution makers and we can deal with them properly.”

The Earth director said there should also be financial measures imposed, such as collecting more tax from big polluters.

She said authorities should also collect a wastewater treatment fee from everyone to promote the whole of society getting involved in tackling the problem because everyone contributed to the issue.

Industrial Works Department (DIW) director-general Mongkol Pruekwatana insisted that the department has worked hard with related agencies to properly monitor and control wastewater discharge in the industrial sector.

“Around 35,000 factories across the country are regularly monitored for their wastewater management, as we usually conduct surprise inspections on their wastewater treatment and disposal systems three to four times a year,” Mongkol said.

“If they are found discharging more polluted water than the safe average, the plants will get a warning to improve their wastewater management systems. But if they do not comply, the factories will be shut down.”

He said only a few factories that the department inspected did not pass the pollution standard, and almost all big factories generating more than 7,500 cubic metres of wastewater were under a real-time monitoring system and did not cause a pollution problem.

“We have the monitoring centre at our department that can monitor the wastewater quality of 291 big factories all the time, which makes sure that their wastewater discharge will not affect the environment,” he said.

“It’s not only the wastewater discharge monitoring and control. We are also encourage the industrial operators to reuse, reduce, and recycle water so we can cut down the wastewater discharge at the first place.”

The DIW director-general said most water pollution was caused by small factories and households, which did not have proper wastewater management systems.

“We are trying to build awareness among the operators to save the environment, and I can see that we have made a lot of progress,” he added.