The same firm that wanted to ship tons of sludge from the District of Columbia to two unwilling Caribbean islands is now negotiating with city officials to transport the liquid refuse to South America.

City Administrator Elijah B. Rogers said yesterday that District officials are considering a new plan by Steuart Environmental Services that would move a maximum daily shipment of 900 tons of sludge from Washington to Colombia, where it would be given to a fertilizer plant.

The plan calls for Steuart to pick up the sludge from the District's Blue Plains treatment plant in far Southwest and ship it from Steuart's oil tanker terminal in Piney Point, Md., to Colombia. Steuart's proposal suggests the shipments begin Oct. 15.

In May the D.C. government terminated its agreement with an Alexandria-based firm that twice failed to follow through on its contracts with the city. Since withdrawing from the contract with Dana Resource Recovery Inc., the city has had to continue paying up to $45 a ton to have its waste hauled daily from the treatment plant to a storage area in Virginia. The District would pay $24 for each ton picked up by Steuart.

Last year Steuart and the District considered disposing of Washington-area waste by shipping it to Haiti or Antigua, but those plans fell through when both countries objected.

Rogers said the Steuart plan is being considered by D.C. Department of Environmental Services director William Johnson and Department of General Services administrator Carroll B. Harvey, who will make a recommendation to him.

The District is under a court order to find a disposal site for the sludge by fall.

Rep. Stanford Parris (R-Va.), whose congressional district includes the Virginia dumping site now used by the city, is adamant about having the District meet the deadline.

"They can spread it on the parking lot at RFK stadium if they want to, as long as it doesn't go to Virgina," Parris said.

"Sludge is something no jurisdiction likes to have," Rogers said, "But what makes the Steuart proposal so attractive" is that the sludge would be "out of sight, out of mind."