Yale facilities workers are close to completing repairs to damage in Timothy Dwight College caused by two recent sewage overflows, with the expected clearing of drain lines this Friday, Yale Director of Customer Services for Group Facilities Hank O’Neill said.

Due to heavy rainfall, a combination storm-and-sanitation line running from TD to Wall Street backed up on Sept. 18 and Sept. 28, causing sewage overflows in the college’s basement — the area under the dining hall, the computer room, the TV room and the corridors. No student rooms were damaged, O’Neill said. All areas affected were cleaned and sanitized quickly after both overflows, O’Neill said, but workers are still working to repair any structural damage.

To prevent further drain-line backups in the future, the University plans to build additional drain lines, O’Neill said. He said the combination drain line running from TD to Wall Street is prone to backup particularly because of its age.

“There are New Haven city drain lines that are over 100 years old,” O’Neill said. “If there’s rain, the combination line gets overwhelmed — it backs up, it just can’t handle that.”

To fix the current problematic drainage system, Yale plans to create and connect a 30-inch sanitary drain line from TD to Church Street to eliminate the college’s dependence on the combination line on Wall Street, O’Neill said.

Yale is also working with New Haven to create long term strategies for improving city drain lines which affect Yale buildings.

“Whenever we have a problem, we always look for engineering solutions,” University Deputy Director of Facilities Operations Eric Uscinski said. “We’re working out the details right now.”

While the creation of drain lines is part of future plans, O’Neill said he was impressed by the response efforts of those who worked to clean during the hours immediately after the flood. The dining hall, which was flooded with “95 percent grease and some rain water,” was quickly cleaned and re-opened, O’Neill said.

“We had a contractor sanitizing all the areas that were hit,” O’Neill said. “That was our first priority because the dining hall was hit pretty hard. It was [a matter of] strictly cleaning and sanitizing the spaces so the Health Department would allow them to open again.”

O’Neill said workers will soon replace the carpeting in the computer and TV rooms. They will also replace portions of the walls in the TV room, he said.

Students complimented the cleaning services for their quick and effective response to the second flood.

“It cleaned up pretty nicely,” Samarth Keshava ’07 said. “Now there’s no smell.”

Although the cleaning process had to be repeated after the second overflow, it was easier the second time, O’Neill said.

“There’s always a possibility that things could back up,” he said. “The second time was a quicker recovery because the carpets had already been removed.”

O’Neill said he did not know the total cost of cleanup efforts because he has not yet received invoices from contractors.