Purdue announced it would be closing the Lothian grain elevator Anne Arundel County Executive Steuart Pittman announced that the county is buying it, to the relief of Southern Maryland farmers.   Mr. Pittman says Purdue has 90 days to consider its proposal, valued at $1, 250,000 to buy the elevator. Many farmers across the country and locally are hopeful that once the elevator is purchased, the county will find an elevator operator who will offer to store their grains at reasonable prices. Farmers are finding that they are paying more and more for storage, and as a result, some say they are operating at a loss.