The concession comes ahead of a Supreme Court ruling on the case. PCD director-general Wichien Jungrungruang yesterday said a compensation payment was inevitable since construction had been completed.
''The case is a tough job. It is hard to say that the department will not have to pay more money to the company,'' Mr Wichien said. ''The fact is that we will have to pay; the question is how much.''
He said that if the Supreme Administrative Court upheld the lower court verdict, the department would have to pay compensation to NVPSKG Joint Venture. In January, 2011, an arbitration committee ruled the department had to pay nine billion baht to NVPSKG, saying the consortium had already completed the work it was contracted to do.
The PCD appealed against the ruling to the Central Administrative Court, arguing the process to establish the arbitration panel was unlawful. In November, 2012, the court ruled in favour of the consortium.
The department then appealed to the Supreme Administrative Court.
The PCD signed a contract with NVPSKG in 1997 to build the waste water treatment plant in Samut Prakan, but scrapped the contract and accused the consortium of contract fraud when construction was about 98% complete.
Mr Wichien said the department had no authority to reach a settlement.