Sludge: The Material
Part I: Disposal of sewage sludge is one of those issues everyone would like to avoid, but they can't; so the first question, "What is it?"

(from Maine Townsman, May 1993)
by Jo Josephson, Assistant Editor

Sewage sludge, the by-product of the Clean Water Act, the by-product of wastewater treatment plants, its disposal is the object of much attention these days.

Not only at the federal level where new regulations regarding its disposal have recently been promulgated and at the state level where existing rules are being revised, but at the local level as well, sewage sludge has generated a lot of activity.

Farmers are said to love the treated sludge. Not only is it high in nitrogen, phosphorous, lime and organic matter, it's also free for the spreading.

Their neighbors aren't always so sure about it, especially since it comes "from away." Disturbed by its odor and what they see as potential health threats, a number of towns are trying to regulate its spreading in their communities.

From moratoriums on spreading, to relatively benign local ordinances, to outright bans, townspeople are telling authorities we don't trust you; we want more information; we want to be kept better informed; we want more assurances; we want more control; we want to be the extra cop on the beat.

While none of their ordinances have been tested in the courts, they have in at least one known case in Pittsfield caused a farmer to drop his plans to spread sludge from the Portland Water District on 46 acres of his land.

In reaction to his plans, residents last December passed an interim ordinance giving local authorities the right to ban out-of-town sludge from being spread in town but not before the elected officials submitted the application to a third party for a closer look.

Not wanting to incur the displeasure of his neighbors, the farmer backed off. And the town? Having won the first round, plans to enact a further ordinance that would impose expensive conditions on any would-be sludge spreaders on the back burner were put into action.

Out-of-town sludge was also the subject of an ordinance in Thorndike at this year's March Town Meeting. It too required local approval before spreading could occur. As the residents saw it:

" ..(W)hile the State has adequate scientific capacity to regulate landspreading of residuals, it has limited resources for incorporating meaningful public input into its review process and closely monitoring spreading operations across the state. Hence, while accepting the State's role in reviewing material safety standards, the authority for additional local review and oversight is essential to ensuring adequate protection of the public health, safety, and peace of minds.

Pittsfield and Thorndike are two latest towns to enact ordinances governing sludge spreading in their towns. New Gloucester, which has been receiving sludge from Portland and Lewiston for a number of years, has had an ordinance on the books since 1986. Also not to be overlooked is Limerick, the latest arrival on the scene of concerned towns. As the TOWNSMAN was going to press, residents there were reportedly seeking a one-year moratorium on the spreading of out-of-town sludge on their lands.

Local government aside, the waste water treatment plants in Maine are getting more active. Realizing they need to do more citizen education, realizing that their options for disposal are growing more and more limited, what with the closure of landfills and the rise in citizen opposition to landspreading, the Maine Wastewater Control Association recently embarked on a project to produce a 20-minute educational video on the landspreading and composting of sludge.

Scheduled for release this fall and filmed in Maine, it is designed to answer some of the major concerns that are being raised.

And last, but not least, Maine's Department of Environmental Protection is gearing up for major action this summer. Its rules on sludge, often touted as the most stringent in the nation, have been on the books since 1976; they were amended in 1986. This summer they will go to rulemaking. Aware of citizen concern, DEP is not waiting for the public hearing this summer but has already begun to seek input from the public as its hammers out its first draft.

As we said, sludge disposal is generating a lot of activity these days. Given that, the TOWNSMAN has attempted to provide some basic background information on sewage sludge.

Part I of this article provides a basic overview of the subject, focusing on the generation and disposal of sludge by the second largest wastewater treatment plant in Maine. It also looks at the amount generated statewide and the reasons why farmers love the stuff and citizens are more wary of it.

Part II looks at the regulations governing the disposal of sludge, comparing the new federal regulations with Maine's current regulations. It also looks at the key players and permitting processing for disposal in Maine. Ant lastly, it looks at activity at the local level, focusing on the ordinance passed by the citizens of New Gloucester in 1986 to control the spreading of sludge in their town.


Lewiston Auburn Water Pollution Control Authority

In 1991, the Lewiston Auburn Water Pollution Control facility produced 17,000 cubic yards or 15,300 semi-solid tons of sludge from the 10 million gallons of wastewater that passed each day through its treatment plant.

Of that amount, 5,000 cubic yards or 4,500 tons, a little less than one-third of the sludge, was spread on farmlands within the city limits and in towns within an hour's drive of the plant. Approximately 12,000 cubic yards or 10,800 tons were landfilled, and a small amount, 123 cubic yards or 111 tons, were composted in a pilot program, according to Clayton "Mac" Richardson, engineer/director of the L/A facility.

The L/A plant has 21 licensed sites and 1,325 acres of farmland under permit from the DEP. Some of the sites are beyond the facility's geographic border in South Fayette, North Leeds, Durham, and New Gloucester.

In New Gloucester there is a local ordinance governing the spreading of the sludge that, among other things, requires a review by the planning board and the monitoring of wells adjacent to the spreading area.

Clayton "Mac " Richardson, the plant's chief engineer, says he does not view New Gloucester's ordinance as a problem. "They are trying to address real concerns. They are not saying: Ban the sludge; what they are saying is: 'Let's look out for ourselves'."

In 1991, the L/A plant spread its 5,000 cubic yards on 700 acres of 14 of its 21 state-licensed sites at no cost to the farmer. It cost the facility about $15 a cubic yard or $75,000 to analyze the sludge, obtain the permits, truck the sludge and spread it on the farms, says Richardson. He says the figure is a "crude estimate."

Like many wastewater treatment plants in Maine, the L/A facility uses a private consulting firm to put together its application to DEP. Resource Conservation Services (RCS) of Brunswick does the actual spreading in most cases; L/A provides the trucks.

Richardson describes the reuse of sludge as "The tail wagging the dog." He recalls when the L/A plant first went on line and a large educational chart was designed for the vestibule tracking the treatment process. "It ended with a picture of a truck. It was only half the picture," says Richardson.


Sludge Production and Disposal in Maine

More than 200,000 semisolid tons a year of wastewater treatment plant sludge are being generated by Maine's 100 plus publicly-owned municipal wastewater treatment plants, according to the Maine Waste Management Agency, Portland Water District is the largest generator of sludge; the Lewiston-Auburn Water Pollution Control Facility is the second largest.

At last report, by volume, Maine was returning 63 percent of its sludge to the soil. At last report, 77 percent of the treatment plants were reusing the sludge. A closer look at the figures compiled by Brian Kavanah of the Maine Department of Environmental Protection indicates that by volume, 37 percent of the sludge was being landfilled, 28 percent was being landspread, 23 percent was being composted and 12 percent was being lime stabilized.

But volume is only one way of looking at disposal. Kavanah also figures that 53 percent of the treatment plants were disposing of their sludge by landspreading, 18 percent of them were composting it, only nine percent were landfilling it.

Landspreading. Composting. Returning the sludge to the soil. They are the preferred methods of disposal by the Maine Waste Management Agency. "Landspreading continues to be the cheapest way to reuse municipal sludge," says Richardson. He figures the cost of composting the sludge is about double the cost of landspreading or $30 a cubic yard.

But as Mary Waring of Resource Conservation Services, the firm that manages L/A sludge spreading program and the Portland Water District's spreading program, notes, "While landspreading is cost-effective, it is limited. You need to replace the acreage every so many years because of the calcium buildup; the soil gets too alkaline to grow the plants. Composting also becomes more competitive as the distance to the farmlands grows," says Waring."

While spreading is cheaper, composting has better public acceptance. It has a better image. It is more trusted. It is more socially acceptable. It has been given "better press," say those in the industry who are turning to composting.

It is L/A's Richardson's goal to "beneficially" use all of the sludge, i.e. 100 percent of it. As noted above, L/A is currently only landspreading one-third of its sludge; most of it is being landfilled. Ultimately, L/A plans to landspread one-half and compost the other half. Practically speaking, L/A has little choice, given the fact that landfilling is no longer an option and to compost all of the sludge would be too expensive.

Having just gained approval for a sludge composting facility on a 118 acre farm in South Auburn, Richardson figures he can produce between 20 and 55 cubic yards of compost per day, six days a week and sell it at $2 to $3 a yard to general contractors and landscapers.

As the largest sludge generator in the state, the Portland Water District is currently producing 28,000 cubic yards of sludge, disposing of it on 25 farms, more than half of which are in the Portland area, according to Jo D. Saffeir of Resource Conservation Services, which also manages the disposal of sludge for the PWD and runs the Hawk Ridge Composting facility in Unity Plantation.

As Saffeir explains, RCS tries to locate farms within a reasonable radius of the treatment plant, about 45 miles is reasonable, she says. But Portland is an exception to this rule. The farms surrounding Portland are small and are being displaced by development. Thus Portland has been forced to look further afield in places like Thorndike and Pittsfield and Monroe and Brooks and Limerick.

But Portland hasn't always trucked its sludge to distant farms. There was a time when it composted it as well. But the town grew up around the comporting facility and the city was forced to idle the operation under pressure from the residents last year; hence the recent trucking further afield.

The PWD is now looking for a "long term solution" to the city's sludge disposal dilemma, according to PWD spokesman Steve Gordon. Along with South Portland it is looking into a regional sludge disposal facility in the Greater Portland area that would be run by Regional Waste System (RWS) the public cooperative that currently incinerates Greater Portland's trash.

It is not known how much of PWD's sludge will go to the facility or what process will be employed, but estimates are that the facility could be on line within 18 months, says Gordon.

Sludge Content

Landspreading and composting are a natural use of sludge because sludge is naturally high in nitrogen and phosphorous and organic matter, just like manure. And when de-watered and treated with lime for the required two hours to kill the pathogens, it makes for a good soil amendment, say those, including the Maine Organic Farmers and Gardeners Association, who advocate its reuse by farmers for growing hay and corn.

L/A calculates that the nutrient value of treated sludge is more than $30 a dry ton; that there are more than 33 pounds of nitrogen in each dry ton of its sludge; that there are more than 290 pounds of calcium/lime in each dry ton of its sludge.

Because of its nutritive quality, those who advocate its reuse have given sewage sludge a new name: "biosolid" to differentiate the material from other sludges, to help counter the negative image associated with sludge management.

"It may sound like double-speak," says Richardson. "But the word sludge is a broad term; it's what we call the stuff that settles to the bottom of an oil tank or a pond. Biosolid tells us the wastewater sludge that is of sufficient quality as to be recycled," says Richardson.

It's definitely cheaper than commercial fertilizers because farmers get it for free from the treatment plants. And its definitely safer than manure and chemical fertilizers, say its advocates because there are regulations governing its use, while there are none governing the use of manure or chemical fertilizers.

While sludge contains many nutrients that farmers need, municipal sludge also contains heavy metals such as lead, cadmium, chromium, copper, mercury and zinc. It also contains pathogens. It is in these two areas that local opposition is rooted.

The DEP claims that 99 percent of the pathogens are killed under its lime stabilization process; the rest are killed when exposed to sunlight and the competition with other pathogens in the field.

They also say that those who believe that any amount of heavy metals "is bad" do not realize that plants require the presence of certain metals such as copper and zinc for their metabolism. However, they also note that Maine soils being naturally acidic are not the best environment for heavy metals. But, as long as the soil isn't too acidic, as long as the pH is kept up, there should be no problem. Which is to say, things will be fine as long as the testing is done and standards are met.

Acknowledging the concerns about the metal in sludge, both the Portland Water District and the Lewiston Auburn Water Pollution Control Authority publish information about the concentration of metals in their sludge.

Both note in their brochures that the heavy metals "fall well within the standards set by the DEP and that its sludge is tested daily for metal content to make sure that farmers receive safe materials." Records are kept on each application site to ensure that maximum lifetime loading limits are not exceeded.

But in these environmentally conscious days of NIMBYISM (Not In My Back Yardism), not everybody trusts what the government says. A look now at what the government says.