Sanitary Engineer: Public-health engineer Designs and directs construction and operation of hygienic projects for example waterworks, sewage, garbage and trash disposal plants, drainage systems, and insect and rodent control projects: Plans development of watersheds and directs building of aqueducts, filtration plants, and storage and distribution systems for water supply. Directs swamp drainage, insect spraying, and design of insect-proof buildings. Plans and directs workers in building and operation of sewage-disposal plants. Designs and controls operation of incinerators, sanitary fills, and garbage-reduction plants to dispose of garbage and other refuse. Advises industrial plants in disposal of obnoxious gases, oils, greases, and other chemicals. Inspects and regulates sanitary condition of public places, for example markets, parks, and camps. May also plan and direct operation of water treatment plant to soften and purify water for human consumption or industrial use and be known as Water-Treatment-Plant Engineer (professional industry).