from the wording in the article, it would seem they already have...

from the wording in the article, it would seem they already have the loan in place with the World Bank and are now figuring out how best to tackle the wastewater management & clean water supply problems.

"The project to improve water supply and sanitation is being carried out under concessional loan financing from the World Bank."

Concessional loans are basically below-market / interest-free financing offered by the World Bank.

I still think it has to be the private sector that needs to fund the majority of the works ... mandating certain water treatment standards for new developments and possibly set a reasonable timeframe for existing premises to be upgraded or face higher taxes / fines may be an effective way to get everyone on board. Governments can then provide similar loan facilities to smaller operators on a case by case basis.. basically passing on the 'cheap' financing so that they can slowly pay it off.

I guess these are the types of things they'll need to think about if they really want to solve the problem at the source. Either way, as you say.. they seem to be taking it very seriously. And with only a couple waste water treatment plants in Cambodia (and we supply the MABR for both of them).. there is massive scope for growth if they start making it compulsory to have waste water treated at resorts/tourist destinations.