MICROALGAE POTENTIAL TO DECREASING DISSOLVED AMONIA CONCENTRATION (NH 3 ) ON LIQUID WASTE OF UREA FERTILIZER FACTORY Fadjar Sidiq Hidayahtullah, Agus Hermawan, and Nuni Gofar 1 Faculty of Agriculture, Sriwijaya University, Jl.Raya Palembang-Prabumulih KM 32 Indralaya, Ogan Ilir Telephone +62821-8667-6002 Faximile (0711) 580644, Email: fchapuchinno@yahoo.com Diterima tanggal 22 Februari 2019 Disetujui tanggal 18 September 2019 ABSTRACT The purpose of this research to analysing the abilities of microalgae from various water treatment processes to improving chemical properties (pH, dissolved NH 3 , BOD, NO 3 - ) the liquid waste of urea fertilizer factory. The sampling method has used the grab sampling method for a certain period. Microarray sources are obtained from various water treatment processes and mixed with waste of water at a dose of 300 mg L-1. The results showed the source of microalgae clarifed was signifcantly different in reducing dissolved ammonia concentration, pH, and nitrate. Based on the results of regression analysis and correlation showed that the microalgae population was partially correlated with pH, BOD, nitrate, and dissolved ammonia of 1.61%, 87.70%, 55.38%, and 9.63%. While the concentration of dissolved ammonia signifcantly affected pH, BOD, nitrate, and microalgae biomass growth of 84.40%. Keywords: Microalgae, water treatment process, dissolved ammonia, urea fertilizer. ©2019 ECOLAB All rights reserved. Open access under CC BY-NC-SA license. doi: http://dx.doi.org/10.20886/jklh.2019.13.2.61-69 JURNAL ECOLAB Vol. 13 No.2, November 2019 : 61-68 p-ISSN 0216-0897 e-ISSN 2502-6267 Terakreditasi RISTEKDIKTI No. 21/E/KPT/2019 61