NASHVILLE, Tenn. -- A project that cost $117 million has come about quietly, without much fanfare or public scrutiny.

It's a new plant that converts sewage sludge into fertilizer. The city said it's an environmentally beneficial way to deal with what goes down the toilet.

But some critics have said it's a colossal waste of money, creating a product nobody seems to want and some people are downright afraid of.

It looks like Oreo cookie crumbles, but you don't dare eat it. This is what's left of what goes down a sink or toilet in Nashville once it's processed in a new, multimillion-dollar way.

Dehydrated, heat dried and shaken out as pellets, it's sewage -- human waste -- now politely called biosolids.

"When you look at the amount of sewage sludge that we had before, you know, taken down to this very small, you know, dried pellet, it's pretty amazing," said Sonia Harvat.

For years, at a cost of nearly $12,000 a day, Nashville's sludge sloshed in the beds of semi trucks, headed for the few out-of-state landfills that would still put up with the stink.

The tidier pellets are also trucked out of state, and the city is still paying for them to be hauled away.

"I believe we were paying $30 per ton to haul it. So we're currently paying $20 per ton for Manco to use it on reclamation sites, so when we have the final product, we'll be selling for $7.50 a ton and not paying for the hauling," said Harvat. "It will be a true savings."

But others see a losing proposition. They call the pellet plant, already nine months behind schedule, wildly expensive, unnecessary and unsafe.

"Think of what we could have done instead with that money," said John van der Harst.

An environmental expert, known for his frugal lifestyle, van der Harst said the city could have created a sophisticated garbage-sorting operation for far less, earning a whole lot more on the recyclables it cherry-picked.

"Even if we landfill the sludge, you know, if you recover 15 times that amount of material, and that material is much higher value, metals, plastics things like that, that on average we figured when we did our calculations brought a benefit to the economy of approximately $550 a ton," said van der Harst.

The contract for the pellets brings $7.50 a ton, if and when they sell.

"Del Monte, Gerber, Heinz -- none of those companies will take any vegetables that have been grown on land that has been spread with biosolids," said activist Maureen Riley.

Riley has made a name for herself in Canada fighting sludge. She said there's no market for the pellets as fertilizer -- too many heavy metals.

"There's nothing beneficial about arsenic, lead, mercury, cadmium," Riley said. "These are toxic metals. Human beings are not supposed to be exposed to them."

No one has yet tested pellets for drugs and other pharmaceuticals that can survive typical wastewater treatment.

Even what are called class A pellets -- the kind Nashville is producing -- can change, Riley said, when they get wet.

"If you had a bag of it and you put it in storage and it got damp, well, the bacteria will multiply in it, and some of the American class A material has come to the Canadian border and been found to be contaminated with salmonella," said Riley.

So Nashville is now in the biosolids business. It can boast that part of the process is powered by the very methane gas the sewage creates.

Yet, three times since August, the silos, where the bacteria chew up the sludge, have overflowed like a pot on the stove. Fine-tuning that problem is almost certain to increase the overall price tag.

"If it's an improvement over the long run that's going to help and benefit, we'll negotiate partial sharing of that payment in additional funds," Harvat said.

Cost is a problem in other cities with pellet plants. This month, Chicago learned that it would be cheaper to close its new plant than make the adjustments that now need to be made.

One other concern may be fire. Several of these plants in the states and in Canada have had fires. And safe storage of the pellets is key, because they can spontaneously heat up.

Metro Water said it isn't a big concern in Nashville, since just a small amount of the product is being kept in reserve for possible use down the line on city golf courses.

Riley said she expects to see a fire associated with the plant within four years.