Formation of Struvite from dairy cow urine by aeration and crystallization using a vertical reactor
Luluk Edahwati (a*), Wahyu Dwi Lestari (a), Sutiyono (a), J Jamari (b), A P Bayuseno (b)

Department of Mechanical Engineering, Faculty of Engineering, University of Pembangunan Nasional ^Veteran^ Jawa Timur, East Java, Indonesia,
Jl. Raya Rungkut Madya, Gunung Anyar, Surabaya, Indonesia, Phone : +62 (031) 870 6369
*Lulukedahwati[at]gmail.com

Department of Mechanical Engineering, Faculty of Engineering, Diponegoro University
Jl. Prof. Soedarto, Tembalang, Semarang 50275, Indonesia, Phone: 024-7460059

Abstract

Struvite is a white crystal which is chemically known as magnesium ammonium phosphorus hexahydrate (MgNH4PO4&#42895-6H2O) which is formed with the same molar ratio. Struvite dissolves readily in acidic conditions and slightly soluble in neutral and alkaline conditions. The phosphate and ammonium content in the urine of dairy cows has a high amount too. The process of forming struvite from dairy cow urine is carried out using the aeration method in a vertical reactor. MAP solution was prepared by reacting Mg: NH4: PO4 using a molar ratio of 1: 1: 1. The solution was made at pH 9 while temperature variations were 25, 35, 45 oC. The air rate is kept at a cost of 0.5 liters / minute. The struvite precipitate obtained was filtered and then dried. The results showed that the percentage of phosphate and ammonium as the best struvite formers at 45&#730-C was 33.2% and 26.9%.

Keywords: #aeration #crystallization #struvite #urine #vertical reactor

Topic: Engineering