The puzzle of the big deep hole in North Lawrence is almost solved.

It has taken two years longer than expected, but city officials are a couple weeks from completing a project to install enhanced sewer service at the Lawrence Municipal Airport, which is expected to open up possibilities for companies to locate small-scale facilities at the airport.

“The sewer situation is what has been holding everything back right now,” said Richard Haig, the chair of the city’s Aviation Advisory Board. “We feel like the door is wide open for development at the airport now.”

The door is opening as city-hired contractors place a lid on a deep, contentious hole. The airport sewer project involved digging an approximately 25-foot-deep hole to bury a storage tank that can hold about 6,000 gallons of sewage produced at the facility. The project was designed to switch the airport from a simple septic system that was becoming overloaded.

Schmidtlein Excavating, of Topeka, began working on the project in May 2011, and was expected to complete the project about 80 days later.

But then the ever-constant North Lawrence challenge of water entered the project. Just a few feet into the dig, large amounts of groundwater began flooding the hole. Crews at one point placed seven temporary wells around the hole in an effort to keep the water out, to little avail.

Philip Ciesielski, an assistant utilities director for the city, said work eventually was suspended on the project and design changes were made. Ultimately, the location of the hole was moved several feet northeast of its originally planned location.

Now that the project is nearly complete, area leaders believe the airport may be poised to attract more attention from companies that are either in the aviation business or simply have frequent air-travel demands.

“A lot of businesses like the idea of operating on a tarmac,” said Greg Williams, president and CEO of the Lawrence Chamber of Commerce. “We think there is tremendous potential out there. We think the completion of this sewer project will kickstart some activity.”

When city commissioners agreed to the sewer project in 2011, there were two aviation-related companies that had an interest in building facilities at the airport. An Ottawa-based company that wanted to house helicopters at the airport had expressed strong interest in a new hangar and office building. And Lawrence-based DAR Corp. had proposed a new headquarters building and design and production facility for its aviation design firm.

However, officials with the Ottawa firm previously have said economic conditions have put their plans for a move on hold. The president of DAR said this week his company’s plans also are on the backburner after a contract with a Chinese aviation company did not materialize.

The new sewer system is designed to support the development of new hangars and office space at the airport, but larger scale development would require additional sewer work. In the 2011 plans, city officials were careful not to design the system to serve the larger area around the airport. The area has been proposed to serve as an industrial park, but that was rejected by city commissioners after concerns about stormwater flooding issues and the loss of prime agricultural ground were raised by area residents.

Construction costs for the sewer project came it at about $435,000, up from $411,000 when the contract was bid in 2011. Ciesielski said the additional costs were related to relocating the structure.