Key Caboratory of Chinese Ministry of Education of northwest Water Resource and Environmental ecolog School of environmental and Municipal Engineering 声建墨群骨 xi'an University of Architecture and Technology 1 Classification of pollutants in domestic WastewaterKey Laboratory of Chinese Ministry of Education of Northwest Water Resource and Environmental Ecology School of Environmental and Municipal Engineering Xi’an University of Architecture and Technology 1. Classification of Pollutants in Domestic Wastewater