ABSTRACT Greywater is a waste from kitchen, bathroom, and laundry activities that contains high organic matter. The organic matter contained in the wastewater is utilized by the microalgae Chlorella sp. as a source of nutrient and its reduce the pollutant in wastewater. This study aims to count the number cells of Chlorella sp. which grew in suspension and attached to the Kaldness 1 (K1) b…