Pro Plumbers

Two-handle faucets are most often found in the bathroom, but you see them in some kitchens. Two-handle faucets use three types of mechanisms. The first two are the same as two of the mechanisms used in a single-handle faucet: cartridge and ceramic disc. The third type is a compression (or reverse-compression) mechanism. Compression faucets are the simplest type, using rubber washers that get compressed against one another to seal the valve. They do tend to wear out faster than other faucet types, but are also least expensive to repair.
After completing an apprenticeship program, plumbers, pipefitters, and steamfitters are considered to be journey workers, qualifying them to perform duties on their own. Plumbers with several years of plumbing experience may earn master status by passing an exam. Some states require a business to employ a master plumber in order to obtain a plumbing contractor’s license.

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?
Pipefitters, sometimes simply called fitters, install and maintain pipes that carry chemicals, acids, and gases. These pipes are used mostly in manufacturing, commercial, and industrial settings. Fitters install and repair pipe systems in power plants, as well as heating and cooling systems in large office buildings. Some pipefitters specialize as gasfitters, sprinklerfitters, or steamfitters.
Plumbers in Australia have licensing requirements that differ from state to state but it is generally accepted a 4-year apprenticeship with a further minimum experience of 2 years (6 years total) and a further curricular requirement as a benchmark for licensing. Licensed plumbers are also expected to maintain minimum relevant training requirements to maintain their plumbing license