Managing the legacy of landfill - Waste Management World

Eastern Daily Press - September 24, 2011

The vast mountains of decaying rubbish buried beneath Norfolk's landscape may be hidden from view - but their potential environmental consequences are not so easily masked. Waste dumped by generations of families and businesses is still decomposing, oozing toxic chemicals and greenhouse gases which could threaten their natural surroundings.

But the challenge of managing our landfill legacy is being met through an innovative engineering effort, while policy-makers continue battling to find more sustainable ways to dispose of the refuse left by a growing population.

Norfolk County Council is responsible for more than 150 closed landfills, of which six are the larger "permitted" sites which were still operating by the time new environmental regulations came into force in the 1990s. Teams of technicians work to a double remit: to monitor and minimise the ecological impact of gas and leachate generated by so much buried waste, and to find ways to maximise income from its useful by-product - methane.

Turning the greenhouse gas into energy at four sites is currently worth about £280,000 per year to the county council, 22pc of the total costs for managing the authority's closed landfills.

Meanwhile, water percolates through rotting rubbish, collecting chemical contaminants as it goes, and the resulting leachate must be routinely monitored, abstracted and sent away for treatment. In all, keeping permitted sites in compliance with environmental regulations costs taxpayers about £1.4m per year.

Bill Borrett, Norfolk's cabinet member for environment and waste, said: "I think people have got to understand more about landfill, because once you understand the amount it costs, the environmental hazards and the amount of space it takes up, people become more aware of the legacy of their waste and the importance of recycling.

"It is not simply put into a hole and forgotten about - there is years of work in maintaining the land after that." The site at Mayton Wood, near Coltishall, accepted 1.5m tonnes of commercial, industrial and household waste between 1971 and 2003. The waste is grouped into huge domed "cells" contained by a liner and capping system.

The base of the landfill consists of a clay base, followed by a waterproof plastic membrane which is protected by a shingle or sand drainage layer above it. At the top, a similar set of layers encase the waste - along with the gas and liquids - in an impermeable bowl, with the angled sides draining any leachate to a collection sump at the bottom. Meanwhile, rainwater is prevented from getting into the landfill, and is instead channelled to the perimeter across the domed surface.

Hydrogeologist Tim Wilkins regularly samples, monitors and controls leachate levels with the help of a computerised system of wells and pumps. "Leachate is what you get when water percolates through the waste and picks up contaminants," he said. "Some of it comes out looking like coffee and smells quite nasty. The main constituent is ammoniacal nitrogen, and it can be quite toxic to the aquatic environment.

"We have got 11 wells on this site and each has a pump and a level sensor which sense the level of the liquid. The pumps are operated automatically when the leachate reaches a level of one metre above the base layer. "All the permitted sites are now within compliance, but when we took them over (in 2008) they generally had 14-15 metres of leachate. They were all saturated, which meant there was more chance of the leachate escaping."

About 70 gas wells are also sunk into the Mayton Wood waste to harness landfill emissions which are typically 45pc methane, 25pc carbon dioxide and the remainder mostly nitrogen. The gas is drawn into perforated pipes which reach 10 to 16m underground to the base of the cell, and are connected through a network of sealed pipes above ground to a powerful fan at the on-site energy plant. The generator draws in 450 cubic metres of gas per hour and converts it to electricity which is sold on to the National Grid, with the profits shared by the council and the private plant operator.

Des Holmes, the council's landfill gas project officer, said: "We're talking about the equivalent of 45 double-decker buses full of gas
being sucked out of the ground every hour. The whole site is under negative suction. "The machinery is basically like a large diesel engine that has been converted to run on landfill gas.

It produces 600kW/h, enough for 500 homes, and it is constant. The only time it stops is when it breaks down, but it can keep going at that rate 24 hours a day, seven days a week. "The gas will diminish over the years, but I reckon we have got about 15 years until it stops becoming economic to produce electricity here." Gas production at closed landfills is estimated to reduce by 10pc each year as the waste degrades, prompting efforts to find more innovative ways of squeezing every last pound out of the resource. The council's strategic waste manager Paul Borrett said there was a "fine balance" between preventing rainwater seeping into the site, and keeping the waste damp enough to maintain chemical reactions.

"The amount of rain water that collects on the site is more than we can cope with, but we want the waste to stay wet so it continues to produce gas," he said. "In trying to reduce the 'tail' of the gas production, we are looking into recycling some of the leachate we have collected back through the waste. Once it gets saturated or if it dried up, we have got no gas production and no income - so it is a fine balance." The generating plant at Mayton Wood also contains a gas flare, to safely burn off any potentially dangerous pressure build-ups of methane, which is estimated to be 21 times more dangerous as a greenhouse gas than carbon dioxide.

Work on the landfill is continuous as the waste compacts, changing the shape of the cap and the effectiveness of the wells. But Paul Borrett said although it could take several decades for landfills to settle, there were plenty of examples of where they had been replanted as woodland, public amenities or even a pitch and putt course.

"A lot of people's view of landfill is a big pit where people throw rubbish away - an eyesore," he said. "But we have moved on from that. We manage our landfills here in Norfolk and you can absolutely get to the point where they can be turned into something that's more useable - but we do have ongoing respon-sibilities and liabilities."

Copyright 2011 Archant Regional Limited All Rights Reserved

View the original article here

Plant to accept more leachate - Waste Management World

BUCHANAN - The wastewater treatment plant in Buchanan will accept up to three times the amount of leachate that it now takes in from the Southeast Berrien County Landfill.

It's a move that will save the landfill $250,000 per year and generate about $50,000 annually for the city, Buchanan City Manager William Marx said.

Leachate is water after it drains through the landfilled trash and collects at the bottom of the dump. It contains a variety of chemicals and other matter from contact with the refuse.

"This is quite a savings for the landfill. We have the ability to take this," said Buchanan Mayor Carla Cole, who's also a member of the Southeast Berrien County Landfill Authority board.

Under an agreement drafted in 1984, Marx said the city's wastewater treatment plant has taken up to 25,000 gallons of leachate per day from the landfill.

Additional leachate from the landfill has been shipped by tanker to a treatment plant in Elkhart at a much higher cost because of transportation costs.

Marx said he recently had lunch with landfill general manager Sonny Fuller and listened to his desire to reduce the expense of shipping leachate.

Marx said he began checking with operators at the wastewater plant and learned as much as 100,000 gallons of leachate per day can easily be safely treated at the plant.

The Buchanan City Commissioners unanimously voted in favor of an agreement this week that allows the landfill to transport additional leachate to the plant through an existing pipeline.

Marx said the move has been approved by the Michigan Department of Natural Resources.

He said the landfill will have to perform some upgrades to its lift station to increase the flows.

Commissioner Dave Hagey applauded what he said he felt was a sample of the creative solutions ordinary citizens don't realize are occurring in local government.

"These are the kind of things percolating below the surface that people don't understand," Hagey said.

Cole said transporting leachate by tanker costs the landfill $115 per hour.

"This is where our biggest savings is going to be," the mayor said.

View the original article here

City commits millions to leachate management - Open File

The city is moving ahead with plans to build a leachate treatment facility at the municipally owned Trail Road landfill—more than seven years after city council first floated the idea.

Over the next three years, $9 million has been set aside to study and build the on-site facility, which will need to be operational by 2015, city spokesperson Jocelyne Turner confirmed in an email.

Landfill leachate is water, generally rain or snow, that seeps through garbage and extracts potentially harmful contaminants. It can pose serious environmental risks if it ends up in the groundwater—precisely the concern that Barrhaven residents brought to council in 2004, when the city was planning to build a pipeline under their homes that would shuttle leachate into the sewer system.

Later that year, council directed the city to study on-site leachate management as well. But the plans were shelved after a new stormwater plan at the Trail Road site, combined with a shift in the city’s overall waste management strategy, led to a significant decline in the amount of leachate being produced, said Turner.

No leachate escaped the site in 2010, she said. But current landfill usage rates mean that by 2015, the landfill cap—the impermeable barrier that separates the contaminated waste from the surface—will need to be removed to expand the site. And with the cap gone, snow and rain will collect and need to be treated, she said.

Most of the overall cost—$8 million—has been earmarked for the construction of the treatment facility in 2014. An additional $800,000 in 2012 will go towards “pretreatment” of the leachate, while the final $200,000 will be spent this year on consulting fees “to select the most effective leachate treatment” at the site, said Turner.

Although the city has not revealed what options are currently being considered, one possible idea might be to incorporate some sort of membrane bioreactor system into the facility, says Roberto Narbaitz, an engineering professor at the University of Ottawa.

Such a system would use bacteria to break down the leachate, which would then be filtered through a thin ceramic membrane, leaving hazardous solids behind, says Narbaitz. The relatively expensive technology would give citizens “bang for your buck” at the start of the process, he says. But once the contaminants are no longer biologically reducible, “it’s not so fantastic," he added.

The “most logical” step would be to treat on-site and revive the cost-effective pipeline idea, although many municipalities are now hesitant to go that route, Narbaitz said.

“There’s fear that there may be some toxic contaminants coming from that landfill ... The possibility is there, but there’s a lot of dilution taking place.”

In her email, Turner said the city can use tanker trucks to haul leachate from the Trail Road landfill to the Robert O. Pickard Environmental Centre, the city's wastewater treatment facility, if necessary. No one from the city was available for an in-person interview.

There are citizens living in the vicinity of the Trail Road landfill whose wells are still contaminated by leachate that, in the past, had seeped into the groundwater, says Ottawa riverkeeper Meredith Brown.

Historically, the city has responded to concerns about leachate only because they’re mandated to do so by the Ministry of the Environment, says Brown, whose organization advocates on behalf of the Ottawa River.

“They’re dealing with it because the province makes them deal with it, essentially,” said Brown. “They have no choice. They’re not doing it out of the goodness of their hearts.”

View the original article here

Poisons contributed by leachate from Malaysian landfills - Waste Management World

WHILE Malaysians are busy worrying about whether radiation-contaminated seawater surrounding Japan's nuclear disaster zone is going to wash onto Malaysian shores, or whether radiation-contaminated food from Japan is going to get past Customs inspections and be consumed by unsuspecting foodies, the fact is, the health of Malaysians have long been at risk of contamination by poisons contributed by leachate from our own landfills.

The poisons, including heavy metals like mercury, leach into groundwater and flow into our rivers, contaminating riverwater and the eco-system that depends on it. If the leach goes undetected, the poisons will flow into our body through the water, fish and shellfish that we consume.

Who is responsible for this insidious poisoning of the people? We are.

Every person who has ever thrown a dry cell battery (like the ones used in torchlights and television remote controls), a fluorescent tube, handphone batteries and other hazardous e-waste like computers, televisions and printers into their household dustbin has contributed to this potential poisoning of the people. Broken or crushed fluorescent tubes leak out mercury gas; dry cells leak out heavy metals. This e-waste, which is scheduled waste, cannot be thrown into an ordinary dustbin, cannot be picked up by an ordinary rubbish-collection lorry, and should not end up on a normal rubbish heap at a normal landfill which is not equipped to deal with leachate.

And yet, every day, more than 42 tonnes of such hazardous e-waste is thrown out together with ordinary household waste.

It is not enough for consumers to know their rights; they must also take responsibility for what they consume, and this includes how they dispose of what they have consumed. But it is one thing to educate the consumer about separating their rubbish; it is another thing altogether to make sure that the rubbish stays separated. Besides building more sanitary landfills with leachate treatment facilities, the government needs to set laws which require e-waste to be compulsorily recycled.

In June 1998, the Japanese government enacted a Home Appliance Recycling Law, in which all white goods were required to be cannibalised and their components recycled. The responsibility for this is borne by the consumer, who pays a compulsory up-front collection charge at the time of purchase, and the manufacturer, who must collect the used product later in the future and recycle it. No government subsidy is involved, as the role of the government is to provide direction to the public to take responsibility for their consumer habits.

Since Malaysia intends to make separation of rubbish at the source for household goods compulsory in 2013, it is only fair that this should be followed through with a plan for how to keep this waste separate.

View the original article here

Petition Pushes EPA to Move on Cement Kiln Dust Management - EP Magazine

Riverkeeper has filed a legal petition forcing the U.S. Environmental Protection Agency to take action on a rule that sets the standards for how toxic cement kiln dust (CKD) is managed by cement producers around the country.

This byproduct of cement manufacturing is often dumped into unlined landfills and old quarries, causing toxic leachate to foul groundwater and surface water. The proposed rule was published in 1999, but due to unyielding pressure from the cement industry, has languished for nearly 11 years, according to Riverkeeper. As a result, no federal standards for CKD disposal exist today.

“In New York and around the country, these unlined landfills ooze toxic leachate and devastate the environment,” said Josh Verleun, Riverkeeper chief investigator and staff attorney. “Through our action, we are seeking to force the creation of federal standards for the disposal of CKD, a substance that when mixed with groundwater, can result in a heavy-metal laden runoff with pH levels comparable to household bleach.”

Riverkeeper is an environmental watchdog organization whose mission is to protect the ecological integrity of the Hudson River and its tributaries, and to safeguard the drinking water supply of New York City and the lower Hudson Valley.

Over the past few years, Riverkeeper has been involved in investigations of several cement plants that have been either been caught (or are suspected of) polluting the Hudson River and its tributaries with contaminated leachate from onsite landfills containing CKD. In 2007, Riverkeeper filed a Notice of Intent to Sue Lehigh Northeast Cement Company for illicit leachate discharges from its unlined CKD landfill. This action led to fines and an Order on Consent mandating cleanup from the New York State Department of Environmental Conservation.

The Lehigh landfill was constructed without a liner or leachate collection system and serves as an example of problem sites around the country that would be addressed through EPA action on Riverkeeper’s petition.

View the original article here