If nothing inside the home was altered you should not be getting a smell. Personally I'm confused as to why the repair person would have left the original line there and ran another one through a new hole. I would have pulled the old line up, ran the new line (in PVC) and used the same hole in the septic tank instead of creating a new one. Did he seal up the hole in the tank from the old line?
Plumbing originated during ancient civilizations such as the Greek, Roman, Persian, Indian, and Chinese cities as they developed public baths and needed to provide potable water and wastewater removal, for larger numbers of people. Standardized earthen plumbing pipes with broad flanges making use of asphalt for preventing leakages appeared in the urban settlements of the Indus Valley Civilization by 2700 BC. The Romans used lead pipe inscriptions to prevent water theft. The word "plumber" dates from the Roman Empire. The Latin for lead is plumbum. Roman roofs used lead in conduits and drain pipes and some were also covered with lead. Lead was also used for piping and for making baths.
“Don’t go to the Yellow Pages to find a plumber,” says Berkey’s Bill Stevens. “It’s like guessing lottery numbers. Anyone can make an appealing ad, but that doesn’t mean they are legitimate. In this industry, it’s easy for a plumber who develops a poor reputation to advertise under a different name. They come and go.” Even searching for someone online may end up being a scam using fake reviews. Instead, look for a plumber who is well-established in your community. Check the Better Business Bureau and read customer reviews at sites such as HomeAdvisor, Angie’s List, or Citysearch. Local contractors or plumbing fixture stores can also refer you to a quality plumber, according to Grady Daniel, who owns a plumbing company in Austin, Texas. “Most of these firms won’t work with bad plumbers.” Or simply ask your neighbors for a referral. A trusted plumber that consistently delivers quality service does not remain a secret for very long.
Jump up ^ "II. The Plumbers". The Atlantic. Retrieved 17 September 2013. In the early evening of June 17, 1971, Henry Kissinger held forth in the Oval Office, telling his President, and John Ehrlichman and Bob Haldeman, all about Daniel Ellsberg. Kissinger's comments were recorded, of course, on the hidden White House taping system, and four years later, a portion of that tape was listened to by the Watergate Special Prosecution Force, which was then investigating the internal White House police unit known as the Plumbers.