BANGOR — Hampden Public Works Director Greg Nash made a special delivery to Bangor City Hall on Thursday morning, dropping off a $1.5 million check that promptly went into the city’s sewer fund.

The money was Hampden’s final payment for the $2.5 million it agreed to pay Bangor for waste-water treatment.

Hampden voters had approved borrowing the $1.5 million over a 20-year period during a referendum election April 16. The item passed overwhelmingly, 195-18.

The town had already given Bangor the first $1 million back in February, money it had been setting aside while waiting for the municipalities to agree on how much was owed.

By the time three years of negotiations had finished, several city councilors in Bangor had publicly expressed their impatience at having to wait so long for the payments from both Hampden and Hermon in their share of the costs of the expansion at the waste-water treatment plant.

Bangor sewer customers had experienced rate increases of up to 10 percent, twice a year over the past several years. The most recent increase approved by the City Council in December was 2 1/2 percent. At the instigation of Councilor Christopher Popper, the council has since voted to have no sewer increases until June 1997.

The Bangor sewer rate is about triple the water rate.

Thursday’s payment to Bangor did not increase sewer rates in Hampden, because the Town Council had increased rates about 20 percent in the late 1980s. That enabled Hampden to save up the $1 million paid in February, as well as plan to make payments on the loan for the $1.5 million.

Bangor City Manager Edward Barrett was obviously pleased to have the $1.5 million arrive on Thursday.

“That closes out the amount they owe us,” he said. It was to Hampden’s advantage to make the payment because the amount owed was accruing interest, Barrett said. The payment would go right into the city’s sewer fund.

In Hermon, the Town Council approved a 30-year interlocal agreement with Bangor in April, promising to pay $127,000 to the city.

On Tuesday, voters at the town meeting in Hermon voted to create a sewer flow reserve, and to use up to $117,000 to purchase additional flow capacity from Bangor.

By increasing its flow capacity from 25,000 gallons to 75,000 gallons per day, the town hopes to be able to accommodate new businesses that need to use the sewer line.