STATEN ISLAND, N.Y. — Staten Islanders rejoiced when, on March 22, 2001, the last of some 2 billion tons of garbage was dumped into the Fresh Kills landfill.

Beleaguered borough residents had waited 53 years for the hated dump to shut down.

But the former 2,200-acre eyesore didn’t stay closed for long.

The landfill has twice been pressed into service as the staging ground for sifting operations to recover the remains of World Trade Center attack victims.

It was first re-opened on Sept. 12, 2001, the day after the terrorist attack — and six months after Staten Islanders thought it was shuttered for good. That operation lasted 10 months.

The second sifting program began April 2 of last year after additional materials were found at Ground Zero. It lasted about 11 weeks.

The operations have aroused a welter of emotions.

While many families rejoiced at the prospect of finding loved ones’ remains, others despaired that the materials were carted to the landfill.

“I don’t think it should have been in a dump in the first place,” said Oakwood resident Michael Mozzillo, whose son, Firefighter Christopher Mozzillo, 27, perished in the attacks. “I’d like to think he’s not there. If he’s been laying around there 10 years, it’s a terrible thought.”

Officials say there are no current plans to resume sifting at Fresh Kills.

“We continue to monitor Ground Zero and we continue to take in material for possible future sifting operations,” said Ellen Borakove, a spokeswoman for the city’s chief medical examiner’ office.

Plans, however, have been in the works since the landfill was shuttered to transform it into Freshkills Park.

Freshkills would be the largest park developed in the city in more than a century, according to the city Parks Department. And to honor the 9/11 victims and recovery workers, the West Mound section between the West Shore Expressway and the Arthur Kill where the sifting operations occurred will be topped with a monument, said officials.

Even so, some victims’ relatives are upset.

The U.S. Supreme Court in October refused to consider a lawsuit by 17 victims’ families who sought to have the landfill researched and a proper burial issued for their loved ones. Remains for 1,121 of the 2,750 World Trade Center victims haven’t been found, said officials.

The families argued that 223,000 tons of the material was never sifted for remains.

Lower federal courts had dismissed the families’ lawsuits against the city, saying it had acted responsibly in moving 1.6 million tons of materials from the World Trade Center site in Lower Manhattan to the landfill and then sifting through the material for human remains.

“Instead of leaving that separate, they bulldozed it under with the rest of the garbage,” said Dennis McKeon, founder of the Great Kills-based Where-to-Turn advocacy group. “Had they left what they sifted through, there was a probability you could have moved it onto a better place than the landfill.”

Long considered a blight to the borough, the landfill was transformed by 9/11 into the biggest crime lab ever and a recovery site, officials said.

Scores of victims were identified during the initial sifting operations, which ended on July 15, 2002.

Eight years later, a new sifting operation began on April 2, 2010, to pore through 844 yards cubic yards of material gathered since December 2007 — about enough to fill a dump truck. The materials had been collected over two years from areas in and around Ground Zero.

The $1.4 million operation concluded at the landfill on June 18, 2010.

No identifications have yet been made from those efforts, although material is still being evaluated, said Ms. Borakove, the medical examiner’s spokeswoman. She said her office is exploring new ways to test unidentified materials from all the recovery efforts.

Officials say a proposed monument for the West Mound will ensure that victims and recovered workers are never forgotten.

The site, which overlooks Arden Heights, Greenridge and Travis will eventually become the West Park section of Freshkills Park. The build-out will occur in phases over the next 30 years and convert the world’s one-time biggest landfill into a world-class park.

Some victims’ kin eagerly await its construction; however, Mozzillo isn’t among them.

“I hate the thought of there being a memorial for my son on a garbage dump,” he said.