Effect of seeding materials and mixing strength on struvite precipitation.
Struvite precipitation has increasing interest as a technology for removing and recovering phosphorus from wastewater streams. Many chemical factors have been studied, such as optimum pH values and component-ion molar ratios, yet, understanding of physical aspects is lacking. Two physical parameters were tested: (1) seeding material addition and (2) mixing. Objectives were to evaluate three seeding materials and to optimize mixing conditions for struvite-crystal precipitation, growth, and subsequent sedimentation. Results confirm that mixing strength and proper seeding materials increase crystal size and improve settleability. For unseeded solutions, optimum phosphorus removal was achieved at a mixing strength of G = 76 s(-1). Struvite crystals that were added as the seeding material provided the best performance with respect to phosphorus removal and crystal-size distribution. Overall, this study provided information to improve the practical application of struvite precipitation as a phosphorous-treatment technology for wastewaters, while generating a marketable slow-release fertilizer as a product.
Wang
Jun
J
Department of Civil, Architectural and Environmental Engineering, University of Missouri-Rolla 65409-0030, USA.
Burken
Joel G
JG
Zhang
Xiaoqi
X
D000818:Animals; D011232:Chemical Precipitation; D017616:Magnesium Compounds / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry*; D000069877:Struvite; D013552:Swine; D014865:Waste Disposal, Fluid / Q000379:methods; D018505:Waste Management / Q000379:methods*; D014867:Water / Q000737:chemistry*
D017616:Magnesium Compounds; D010710:Phosphates; D014867:Water; D010758:Phosphorus; D000069877:Struvite