An $11 million project will clean up open-air drainage canals that carry effluents out of Siem Reap and create a clean, modern wastewater treatment system

Photo by: Peter Olszewski

John Aspinall and the Siem Reap western sewer drain.

YOU'RE probably wondering why we are stuffing up the streets," says engineer John Aspinall by way of introduction. And indeed he is addressing the question that everybody's asking in Siem Reap: Why is one of the main arteries, Sivatha Boulevard, stuffed up and why has it been stuffed up for weeks on end?

The area outside the Lucky Mall has become a quagmire of boggy mud. Chaos reigns. Roadwork means that only a narrow lane is open to traffic. Police were supposed to enforce a one-way rule, but they gave up long ago, abandoning the traffic to sort itself out, and of course the traffic has been unable to sort itself out: It's a snarled mess with vehicles fighting to go both ways in the one lane, spilling out onto the footpath and spewing across the forecourt of the new mall.

Aspinall answers the question of what's going on by taking the Post on a guided tour of the back drains of Siem Reap, as part of his role as team leader of the Siem Reap Wastewater Management Project.

This is the Siem Reap that tourists never see, the effluence that lurks only a few metres behind the affluence of chic hotels.

This, says Aspinall, pointing at a snaking ditch of execrable black water gurgling in its filth, is the town's western sewerage system.

Health hazard

Effluent flows from plastic pipes from houses into this ditch and the "water", along with drainage from storm water pipes, is supposed to flow out of town. But it doesn't flow because it is mired with mud, rubbish and rampant weeds.

So the water sits, stagnates and stinks, sometimes less than a metre from open-air household kitchens.

"This is a very serious health hazard, and I've seen children walking through it," Aspinall says. "People have to walk through it, and people are living next to this stagnant water."

But Aspinall is leading the effort to fix this, a massive project  he's overseeing from his office at the Department of Public Works and Transport on behalf Japanese fim NJS Consultants Co Ltd, for the client organiser, the Ministry of Tourism, as part of an initiative under the auspices of the Mekong Tourism Development Project.

The US$11 million project, which officially started in June 2007 and is now 55 percent complete, is being funded by the Asian Development Bank. Covering the western part of Siem Reap, the project will dramatically upgrade wastewater management, and commences at National Road 6.

Here's the plan

More than 50 hectares of existing piping will be unblocked and fixed, and the drainage ditch that serves as the sewer is being replaced by a wide concrete culvert that runs several kilometres through town. This will carry only storm and drainage water to a pumping station on the edge of town.

"Even though the concrete canal still runs nearby people's houses, they won't be coming into contact with water that's full of effluent," Aspinall says.

Complementing the new canal, officially called the Town Centre Drain, is a large diametre underground pipe running beneath Sivatha Boulevard to the pumping station, and this will carry the effluent.

Aspinall says, "That's why we have temporarily stuffed up Sivatha Boulevard.  We've started to lay the interceptor pipe, which is the main interceptor sewer - interceptor meaning that there are many branch pipes coming from individual houses and hotels which connect up the manholes on the main interceptor pipe, and all the waste flows under gravity to the pumping station.

"When it reaches the pumping station, the pipe is so  deep in the ground that the wastewater has to be lifted to a higher level by the pumps, and then it goes under force - force main we call it - to the water-treatment plant.

"The plant itself consists of various ponds - anaerobic, fermentation and maturation ponds - which hold the wastewater for a given length of time, and in that time there's a bacteriological breakdown which renders the water harmless.

"At that point it goes out into the irrigation system which already exists. The flow goes off into the fields, and none of the flow is polluted."

End of the line

The water-treatment plant, being built out towards Tonle Sap, is immense and, in some ways, futuristic - hectares of huge sloping V-shaped concrete water vats. In other ways, the canal system and concrete vats have an Angkorian feel. It's not hard to imagine archeologists in the 31st century assuming that construction of the ancient Angkor canal system continued on into the early 21st century. "We call it the South Baray," Aspinall smiles wrily.

"Oddly enough very few people know this is going on out here. This is a big and essential asset for Siem Reap, and represents a pretty radical change. Hopefully by next rainy season the town won't get any more of these multiple floods."