The word sludge conjures up the bubbling, glowing, toxic slime that comic book villains always seem to have on hand. But in Maine, town after town has fought a different enemy – the human and industrial waste that is the end product of sewage treatment.

In a debate that pits environmentalists against environmentalists, town councils have weighed the benefits of recycling sludge for use as fertilizer, against the potential health impacts of exposure to these wastes.

Community activists have passionately opposed sludge spreading in their back yards, but to no avail. Maine law gives the state full responsibility for solid waste management. The towns have no legal right to draft ordinances stricter than state law, which creates different classes of sludge with different standards that must be met before they can be used as fertilizer.

On Friday, the Legislature’s Joint Standing Committee on Natural Resources considers a pair of bills that would empower communities to decide whether to allow the use of sludge in their town.

One bill, sponsored by Sen. Christopher Hall, D-Bristol, would grant local communities the right to draft their own sludge restrictions.

The other, sponsored by Rep. Peter Rines, D-Wiscasset, would require that any sludge spreading must meet the contaminant standards for its state of origin.

The process

Each person produces about 175 pounds of raw sludge – what comes out of sewage treatment plants – per year. That’s 150,000 total cubic yards for the whole state. In Maine, the majority is used for fertilizer.

About a dozen communities compost their own sludge. Larger cities such as Bangor, Brewer and Augusta all send it to the region’s largest processor of raw sludge, New England Organics.

Tucked away on the 300-acre Hawk Ridge Farm in Unity Plantation in Waldo County, New England Organics produces treated sludges – there are two kinds – that have been used to fertilize the athletic fields at Waterville High School, the Village Green in Bar Harbor and the Blaine House lawn, among countless other sites.

Supporters, such as company spokesman James Ecker, see the process as a recycling success story. Statewide last year, 18,900 cubic yards of treated sludge was kept out of landfills and put to good use, he said.

“It’s rough to get the people past the thought, ‘I flushed that down the toilet and now I’m putting it on my garden,'” Ecker said. “People think that we’re spreading methyl-ethyl death.”

Instead, a series of Department of Environmental Protection tests safeguard the public and the environment, he said.

Under Maine law, raw sludge must meet standards for the concentration of contaminants including heavy metals, dioxins, pesticides and PCBs before it ever leaves the municipal sewage treatment plant. Sludges that are considered too contaminated must be sent to landfills, explained Brad Moore of the Bangor Wastewater Treatment Plant.

Sludges that pass can take two different paths.

Class B sludge is treated with lime to kill an estimated 90 percent of pathogens such as bacteria, and may be used only on farmland with permits from the Department of Environmental Protection.

Proponents say that Class B sludge is safer than raw animal manure, which traditionally has been used as fertilizer. Opponents fear that live pathogens allowed to remain are a public health risk.

Sludge that is mixed with other organic materials and composted at temperatures in excess of 160 degrees is considered sterilized and named “Class A.” Tests for particularly hardy bacteria such as salmonella and E. coli are conducted at several different points during the process to ensure compliance.

Under Maine law, Class A sludge can be sold for use anywhere, from home gardens to school athletic fields, with no permits required. New England Organics gets as much as $12 per cubic yard for its product, which is marketed under the name “earthlife.”

Ecker rarely even uses the word sludge, preferring the terms “biosolids” or “compost” for its end products.

Tall rubber boots and frequent hand washing are required at Hawk Ridge, but no one wears a mask. Without gloves,

Ecker scoops out a handful of finished compost, brings it to his nose and breathes in the earthy, peaty smell of organic soil.

“We have to test for over 150 compounds,” he said. “The risk is no worse than being on a farm.”

The risk

Critics worry that disease-carrying bacteria, carcinogenic chemicals, heavy metals and even hormones can remain in the sludge that is applied to farmland, contaminating groundwater and harming the people who eventually consume crops and livestock grown there.

State and federal organic standards ban the use of sludge because current regulations cannot give them an absolute guarantee of the materials’ purity.

State law is structured to require that sludge be tested primarily for chemicals that it would be expected to include. For example, sludge from a paper producing town would require frequent dioxin tests, but sludge from a less industrial community might be tested for dioxin only twice each year.

“It’s a very difficult waste to regulate,” said Maggie Drummond of the Maine Toxics Action Center. “We don’t know exactly what’s going into the waste stream from day to day. The state doesn’t test for everything, nor does it test often enough.”

Of greater concern to many members of the public who testified at Thursday’s packed hearing is the sludge that companies such as New England Organics imports from out of state.

Last year, 11 percent of the raw sludge processed at New England Organics came from outside the state, originating in such urban centers as Worcester and Springfield, Mass.

A load of sludge from Springfield that New England Organics dumped in Whitefield last year spurred the creation of a local activist group. The smelly pile was found to include such contaminants as PCBs, diesel fuel and dioxin – though in amounts that did not violate Maine’s standards, residents said.

“The only way I can describe it is that it smelled like a large animal carcass that was left to roast in the summer,” said Carl Regis, a Whitefield resident.

To have sludge deposited near private wells and atop the town’s groundwater aquifer with no recourse is a violation of residents’ civil rights, they said.

The impacts

Industry representatives argued that Maine is a net exporter of sludge, and that new restrictions would destroy an important industry.

Hundreds of thousands of tons of compost – 40 percent of New England Organics’ total sales – goes to Greater Boston, with the profits coming home to Maine’s economy, Ecker said.

Several farmers attended Thursday’s hearing to testify that when used properly, treated municipal sludge is a safe and effective fertilizer, less expensive than many chemical alternatives.

Municipal wastewater plant managers from several communities also testified against the bill, saying community bans on the use of sludge would increase the tipping fee plants pay to processors, and ultimately raise local sewer rates.

Bangor already spends as much as $356,000 each year to test and dispose of its sludge, Moore said.

“Something has to be done with it,” he said. “I would prefer to see it recycled.”

Ecker agreed: “Do you want a landfill in your hometown? Do you want an incinerator? Do you want to load up your 175 pounds of sludge in the trunk of your car?”