After years of criticism by environmentalists and Ironbound residents, Newark’s incinerator that produces energy from municipal waste is about to get a lot cleaner.

Plant operator Covanta said the facility, which burns waste from all 22 municipalities in Essex County and produces enough power for 45,000 households, will be equipped with more than $75 million worth of new technology to cut emissions of lead, mercury and particulates.

"Baghouse" filters will be installed one at a time in 2014, 2015 and 2016 below the facility’s 271 foot tall stack.

The filters get their name from thousands of long bags that act like vacuum cleaner bags to filter out pollutants. Puffs of air knock the pollutants off the bags for collection.

The Christie administration and Newark Mayor Cory Booker both lauded the move.

"Nothing is more fundamental to our wellbeing than the air we breath," Booker said in a statement. "As a strong advocate for this upgrade, I am proud to be celebrating today’s major achievement with Covanta and everyone else who made it possible."

Department of Environmental Protection Commissioner Bob Martin called it a milestone.

"Improving the quality of New Jersey’s air is a top environmental priority of the Christie administration," Martin said in a statement. "I commend Covanta, the Port Authority of New York and New Jersey, and New York City for working as partners with the DEP to reach this important agreement."

The plant is one of only two left in the state without the filters, along with Camden, and that angers Kim Gaddy, chair of Newark’s Environmental Commission.

"This was the newest technology that was available 20 years ago," Gaddy said. "We always felt that was an environmental injustice and environmental racism."

In the last five years, the plant was cited 120 times by the state Department of Environmental Protection, data show.

Those violations weren’t serious, according to DEP spokesman Lawrence Hajna, who called them "almost like blips."

"They didn’t last very long, but technically they were violations," Hajna said. "Based on a review of the last several years, there haven’t been major problems at the plant from an air- pollution perspective."

But the facility did pay the state more than $54,000 in fines since 2007.

The plant, which uses natural gas to start combustion that is then sustained solely by trash, has already come a long way on the path to cleaner operation, said Paul Gilman, chief sustainability officer for Morristown-based Covanta Energy, which also operates 43 other plants like it nationwide.

After 2008, Gilman said, quantities of lead and mercury emitted have declined each year. Those are known as "non-ferrous metals," called that because they don’t contain iron, which has the latin name ferrum.

Gilman said the baghouse technology is only being installed now because while Covanta has operated the facility since 2005, it took until late August to sign a deal with the Port Authority that gave the company decision-making power at the plant.

The DEP also helped push the baghouse filters, according to Hajna, who said the state brought the idea to the table when the Port Authority and Newark were discussing the plant.

"We saw an opportunity to get better controls in there," Hajna said. "We took this transaction that was in the works as an opportunity to work with the partners in upgrading the pollution control equipment."

The baghouse techology will take up a much bigger footprint than the current filters, making the installation a challenge.

"We have to build it, get it set up and ready to go, when the units are off, hook it up, and then turn it on," Gilman said. "It’s going to be a little bit of choreography to get it done because it’s a very tight space."

Meanwhile, inside the plant business will continue as usual: giant claws will move and sort six to eight tons of trash with each huge pincer movement, and loads will get burned at 2000 degrees in three boilers, powering a pair of turbines to produce electricity for the plant and the surrounding community.

Running the incinerator is no easy task because, unlike a wood pellet stove or gas engine, the fuel thrown in is constantly changing.

"It’s the most variable fuel there is," said Gilman. "It’s your household waste, and obviously from one bag to another, different contents. From one truck to another, different contents."

As the waste content changes, computers adjust air injections and movements of grates, with the dual goal of producing the most electricity possible and the least emissions possible.

"This is extremely sophisticated equipment," said Richard Giordano, a Covanta vice president. "It is not your simple, ‘Throw the trash in and burn.’"

Eliot Caroom: (973) 392-7919, ecaroom@starledger.com and @eliotter on Twitter