Thailand’s Pollution Control Department (PCD) and Finance Ministry have lost the legal fight to avoid paying 9.6 billion baht in compensation to a consortium of companies over the corruption-plagued Klong Dan waste water treatment project in Samut Prakan province.

On Monday, the Supreme Administrative Court overruled the Central Administrative Court’s decision to order a retrial of the case, during which an arbitration committee ruled in January 2011 that the government must compensate NVPSKG, a consortium of six companies responsible for building the treatment plant.

The court said that the application, by the PCD and the Finance Ministry, for a retrial of the case lacks new evidence, oral or documentary, to justify for a retrial. The court also ruled that the Finance Ministry is not a party to the legal conflict between the PCD and the consortium and, therefore, has no right to apply for a retrial.

Since the Supreme Administrative Court’s ruling is final, it means that the PCD or the government will have to pay the consortium the compensation, as originally decided by the arbitration committee.

The Supreme Court’s Criminal Division for Political Office Holders found former Deputy Interior Minister Vatana Asavahame and a handful of senior PCD officials guilty of malfeasance in office.

The controversial waste water treatment project was approved in 1995. It was intended to be the largest treatment plant in Asia, with the capacity to treat water discharged from plants in Samut Prakan at a rate of 525,000 cubic metres per day.