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. Work involves 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; and cleaning treatment plant structures and equipment.