Modeling of Nitrogen Conservation by the Addition of Mg and P Salts Mixtures for the Management of Urban Food Waste Treatments

A nitrogen conservation model in the thermophilic composting process of simulated food waste, in which phosphate and MgSO 4 mixtures (K 3 PO 4 + MgSO 4 , K 2 HPO 4 + MgSO 4 and KH 2 PO 4 + MgSO 4 mixtures) were introduced for nitrogen (NH 4 + -N) conservation, was developed for the management of composting combined with Contois function. The established model showed good agreement with experimental observation for NH 4 + -N conservation. It appeared that K 3 PO 4 + MgSO 4 of experiment Run B produced less MgNH 4 PO 4 middot6H 2 O than K 2 HPO 4 + MgSO 4 of Run C or KH 2 PO 4 + MgSO 4 of Run D. The average fixation fraction of Runs B, C and D was respectively 30.77%, 69.38% and 73.13%.