Auto-Nucleation and Crystal Growth of Struvite in a Demonstrative Fluidized Bed Reactor (FBR)

Abstract

The experience of P removal by auto-nucleation and crystal growth of struvite (MAP) in a demonstrative plant is proposed. The demonstrative plant is located in a municipal wastewater treatment plant in northern Italy. The trials are a consequence of previous experimentation carried out using silica sand as seed material. Working in metastable conditions the auto-nucleation process is performed, and allows the control of the precipitation and the growth of MAP inside the FBR reactor. No scaling problems are observed in the collecting pipes. After the treatment of 650m3 of anaerobic supernatants, 0.28 tons of granulated crystalline MAP are produced. The chemical analysis shows its possible use in agriculture as fertilizer. Operative costs analysis confirms the SCP as a cheap way to remove and recover P from anaerobic supernatants.

Optimization of struvite precipitation in synthetic biologically treated swine wastewater—Determination of the optimal process parameters

“…Calcium carbonate, brucite and calcium phosphate could have precipitated in these fractions. The precipitation of CaCO 3 has been already observed in struvite precipitation processes [15,52]. The optimization aimed to minimize [PO 4 3− -P] e and ammonia volatilization, and maximize the production of big particles of struvite.…”

Phosphate removal in agro-industry: Pilot- and full-scale operational considerations of struvite crystallization

“…Most full-scale struvite plants do treat anaerobicliquor originating from primary and secondary sludge digestion (Ueno and Fujii, 2001;Battistoni et al,2005;Forrest et al,2008). This paper describes the successful use of afairly straightforward stirred tank crystallizer for full-scale phosphate recovery by struvite crystallization treating anaerobic effluent from a dairy processing industry at an average flow rateof100 m 3 /h.…”

A comprehensive understanding of saturation index and upflow velocity in a pilot-scale fluidized bed reactor for struvite recovery from swine wastewater

“…The loss of fines took place especially at high upflow velocity that was needed to maintain the growing particles in suspension [47]. Better TP removal meant more retention of struvite in the FBR, which could facilitate the granulation of struvite pellets later, under proper hydrodynamic conditions.…”