Des Moines-based Dwolla Inc.’s digital wallet service has been selected by the federal government for use as one of two web-based payment options by the federal government, the Treasury Department announced last week. Pay.gov, the government’s secure web based collection portal for payments to federal agencies, now offers both PayPal and Dwolla as payment options. The implementation is part of an ongoing effort to move away from paper-based processes to more efficient and secure electronic transactions for the federal government, the agency said. In Fiscal Year 2014, the Fiscal Service collected $3.73 trillion in revenue processing 400 million transactions through several programs, including Pay.gov. Nearly 98 percent of those transactions were settled electronically.