Phosphate removal in agro-industry: pilot- and full-scale operational considerations of struvite crystallization.
Pilot-scale struvite crystallization tests using anaerobic effluent from potato processing industries were performed at three different plants. Two plants (P1 & P2) showed high phosphate removal efficiencies, 89+/-3% and 75+/-8%, resulting in final effluent levels of 12+/-3 mg PO(4)(3-)-PL(-1) and 11+/-3mg PO(4)(3-)-PL(-1), respectively. In contrast, poor phosphate removal (19+/-8%) was obtained at the third location (P3). Further investigations at P3 showed the negative effect of high Ca(2+)/PO(4)(3-)-P molar ratio (ca. 1.25+/-0.11) on struvite formation. A full-scale struvite plant treating anaerobic effluent from a dairy industry showed the same Ca(2+) interference. A shift in the influent Ca(2+)/PO(4)(3-)-P molar ratio from 2.69 to 1.36 resulted in average total phosphorus removal of 78+/-7%, corresponding with effluent levels of 14+/-4 mg P(total)L(-1) (9+/-3 mg PO(4)(3-)-PL(-1)). Under these conditions high quality spherical struvite crystals of 2-6mm were produced.
Moerman
Wim
W
Akwadok, Hoekstraat 3, Deerlijk, Belgium.
Carballa
Marta
M
Vandekerckhove
Andy
A
Derycke
Dirk
D
Verstraete
Willy
W
D000383:Agriculture; D003460:Crystallization; D017616:Magnesium Compounds / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D010865:Pilot Projects; D000069877:Struvite
D017616:Magnesium Compounds; D010710:Phosphates; D000069877:Struvite