Marshfield Municipal Airport hopes runway renovation will begin in mid-August, pending the release of funding from the Federal Aviation Administration, airport manager David Dinneen said. The apparent low bidder, though not formally approved as such, is Lawrence-Lynch Corp. of Falmouth, he said. The airport plans to lengthen and widen the runway and replace the lighting and navigation systems. Energy-efficient LED lights will be used for the taxiways, but not the runway, because they are not approved for that purpose by the FAA, he said. The airport requested just over $13 million from the FAA; additional money will come from the state and a town bond of $200,000. Engineering and construction costs are expected to total $15 million. The changes are intended to enhance safety for existing flights, not to expand into new types of service, he said.