OBJECTIVETo investigate the struvite precipitation under constant and non-constant pH conditions and to test a stainless steel device under different operating regimes to maximize the recovery of struvite.

METHODSThe molar ratio of NH4+: Mg2+: PO4(3-) was adjusted to 1: 1.2: 1.2 and pH was elevated to 9.0. The absorbance measurement was used to trace the process of struvite crystallization. Wastewater and precipitate analysis was done by standard analytical methods.

RESULTSThe pH constant experiment reported a significantly higher struvite precipitation (24.6 +/- 0.86 g) than the non-constant pH experiment (19.8 +/- 1.86 g). The SAR ranged from 5.6 to 8.2 g m(-2) h(-1) to 3.6-4.8 g m(-2) h(-1) in pH constant and non-constant experiments, respectively. The highest struvite deposit on the device was found in regime 3 followed by in regimes 2 and 4. The highest PO4(3-) (97.2%) and NH4+ (71%) removal was reported in the R1 regime. None of the influent Cu2+ or Zn2+ was precipitated on the device.

CONCLUSIONA higher struvite yield is evident in pH constant experiments. Moreover, the stainless steel device facilitates the isolation of heavy metal free pure (around 96%) struvite from swine waste biogas digester effluent contaminated with cu2+ and Zn2+ and the highest yield is attainable with the device operating at 50 rpm with agitation by a magnetic stirrer.

Animals ; Bioreactors ; Chemical Precipitation ; Hydrogen-Ion Concentration ; Magnesium Compounds ; chemistry ; Manure ; Phosphates ; chemistry ; Stainless Steel ; Struvite ; Swine ; Time Factors ; Waste Disposal, Fluid ; instrumentation ; methods

A large stone with 8.7 cm multiply 7.2 cm multiply 6.5 cm in size and 420 g in weight dropped down spontaneously from a 93-year-old man's scrotum, who had suffered from left intrascrotal mass and pain for more than 20 years. The component of the stone was magnesium ammonium phosphate. To the best of our knowledge, it is the largest intrascrotal calculus reported in the world. We hereby present the case and discuss the diagnosis and etiology of scrotal calculi.
Aged ; Aged, 80 and over ; Calculi ; chemistry ; diagnosis ; etiology ; Humans ; Magnesium Compounds ; analysis ; Male ; Male Urogenital Diseases ; diagnosis ; etiology ; Phosphates ; analysis ; Scrotum ; pathology ; Struvite

OBJECTIVETo investigate the feasibility of nitrogen and phosphorus recovery from swine waste biogas digester effluent and the effects of pH and NH4+: Mg2+: PO4(3-) molar ratio on its precipitation.

METHODSPrecipitation experiments with swine waste biogas digester effluent were conducted at pH 7.5, 8.0, 8.5, and 9.0 together with NH4+: Mg2+: PO4(3-) molar ratios 1: 0.2: 0.08, 1: 1: 1, and 1: 1.5: 1.5. Chemical and X-ray diffraction (XRD) analysis were done to determine the composition of the precipitate.

RESULTSThe highest removal and recovery of NH4+ and PO4(3-) were achieved at pH 9.0 in each experiment. The elevation of pH to 9.0 alone could decrease the initial PO4(3-) concentration from 42 mg L(-1) to 4.7 mg L(-1) and 89.2% PO4(3-) recovery was achieved. The pH-molar ratio combination 9.0-1: 1.5: 1.5 effected 76.5% NH4+ and 68.5% PO4(3-) recovery. The molar ratio of 1: 1: 1 together with pH elevation to 9.0 was determined to be the optimum combination for both NH4+ and PO4(3-) removal as it recovered over 70% and 97% of the initial NH4+ and PO4(3-), respectively.

CONCLUSIONSNitrogen and phosphorus can be recovered from biogas digester effluent as struvite.

Animals ; Bioelectric Energy Sources ; Bioreactors ; Chemical Precipitation ; Hydrogen-Ion Concentration ; Magnesium Compounds ; chemistry ; isolation & purification ; Manure ; Nitrogen ; chemistry ; isolation & purification ; Phosphates ; chemistry ; isolation & purification ; Phosphorus ; chemistry ; isolation & purification ; Struvite ; Swine ; Waste Disposal, Fluid ; X-Ray Diffraction

Objective: To explore the etiological factors for calculus-associated seminal vesiculitis by analyzing the composition of seminal vesicle calculus samples. METHODS: This retrospective study included 6 cases of recurrent hematospermia diagnosed with seminal vesicle calculus by non-contrast pelvic CT. The patients were aged 28 to 69 years, with persistent or recurrent hematospermia for 3 months to 6 years, and 5 of them with a history of acute urethritis. All the patients underwent seminal vesiculoscopy, which confirmed calculus-associated seminal vesiculitis. The calculus samples were obtained with a spiral dislodge and their composition was determined with a second-generation infrared calculus composition analyzer. The patients were followed up for 2 to 12 weeks postoperatively, during which non-contrast pelvic CT was employed for observation of recurrent calculus in the reproductive tract. RESULTS: Pelvic CT scanning indicated recurrence of seminal vesicle calculus in 3 cases at 12 weeks postoperatively, of which, 2 were accompanied with recurrent hematospermia, both observed at 4 weeks after operation. As for the composition of the calculus, the infrared calculus composition analyzer revealed struvite (magnesium ammonium phosphate hexahydrate) in 5 cases and a mixture of calcium oxalate dihydrate, calcium oxalate monohydrate, and carbonate apatite in the other one. CONCLUSIONS Seminal vesicle calculi are most commonly composed of struvite, and infection is the main etiological factor for calculus-associated seminal vesiculitis.
Adult ; Aged ; Apatites ; analysis ; Calcium Oxalate ; analysis ; Calculi ; chemistry ; complications ; diagnostic imaging ; Genital Diseases, Male ; diagnostic imaging ; etiology ; Hemospermia ; etiology ; Humans ; Male ; Middle Aged ; Postoperative Period ; Recurrence ; Retrospective Studies ; Seminal Vesicles ; diagnostic imaging ; Struvite ; analysis ; Tomography, X-Ray Computed ; Urethritis ; etiology