primary settling tank - qualified craftsmen
- primary settling tank
- primary sewage
- primary sewage treatment
- primary sludge
- primary standards
- primary stress
- primary surface
- primary system
- primary treatment
- primary treatment of wastes
- primary treatment plant
- primary truss
- primary water
- primary-secondary system
- primate city
- prime
- prime beam
- prime coat
- prime coating
- prime contract
