<p>The present study investigates the phycoremediation potential of the freshwater microalga <i>Chlorella vulgaris</i> using paper mill effluents. The microalga was grown in various concentrations of paper mill effluent under laboratory conditions and harvested on the 14^th day. Maximum biomass productivity was achieved in 50% paper mill effluent. Based on the physicochemical properties of the treated effluent, the results indicate that <i>Chlorella vulgaris</i> biomass significantly reduced organic pollutants, heavy metals, and nutrients throughout the cultivation period. Fourier Transform Infrared Spectroscopy, High-Performance Liquid Chromatography, and Gas Chromatography-Mass Spectrometry analyses revealed that the fatty acid methyl ester profile of <i>Chlorella vulgaris</i> included phosphonic acid, carbamic acid, oleic acid, cyclopentane carboxylic acid, octadecenoic acids, octadecadiynoic acid, butanoic acid, and cyclopentane propanoic acid. This study demonstrates that <i>Chlorella vulgaris</i> is a suitable microalga for the phycoremediation of paper mill effluent and for achieving higher biomass production, contributing to sustainable biodiesel production</p>