Work includes operating process pumps, motors, blowers, and other wastewater treatment plant equipment; taking samples of sewage, effluents, and sludge; performing simple, routine laboratory tests, including sludge settling, centrifuge, and chlorine residual tests; cleaning treatment plant structures and equipment; and performing mechanical repairs on tanks, pumps, plant generators, mixers, aerators; center contacts, air compressors, chlorination equipment, lime and other chemical feed equipment, grit removal systems, mechanical screens, sludge dewatering equipment, and other equipment used in booster plants and utility lift stations. In cold; In dampness or chilly conditions; In heat; In high humidity; In or with dusty conditions; In or with moving objects or vehicles; In or with noisy conditions; On or with ladders or scaffolding; On slippery or uneven walking surfaces; Other working conditions; With chemicals or solvents; With electricity; With feet, legs or hands in water; With fumes, smoke, gases or flames; With grease; With hazardous materials; With lawn grasses, plants, etc.