Effect of Calcium Additive on the Crystallization of Struvite Dyah Suci Perwitasari, Luluk Edahwati, S. Sutiyono, Novel Karaman, J. Jamari, Stefanus Muryanto and Athanasius.P. Bayuseno MATEC Web of Conferences, 58 (2016) 01007 Published online: 23 May 2016 DOI: 10.1051/matecconf/20165801007