Struvite

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Struvite
Specific gravity
1.7
Optical propertiesBiaxial (+) 2V Measured: 37°
Refractive indexnα = 1.495 nβ = 1.496 nγ = 1.504
Birefringenceδ = 0.009
SolubilitySlightly soluble, dehydrates in dry, warm air
Other characteristicsPyroelectric and piezoelectric
References[2][3][4]

Struvite (

specific gravity
of 1.7. It is sparingly soluble in neutral and alkaline conditions, but readily soluble in acid.

Struvite urinary stones and crystals form readily in the urine of animals and humans that are infected with ammonia-producing organisms. They are potentiated by alkaline urine and high magnesium excretion (high magnesium/plant-based diets). They also are potentiated by a specific urinary protein in domestic cats.

Name

Although struvite was briefly mentioned in Hooke's Micrographia,

medieval midden in Hamburg, Germany; he named the new mineral after the geographer and geologist Heinrich Christian Gottfried von Struve [de] (1772–1851) of Hamburg.[6][3]

Occurrence

Struvite readily forms in alkaline conditions where its constituent ions are present. In nature, it forms primarily in areas associated with organic matter decomposition, including

marshlands. Similar conditions are found when human bladders are infected by urease-producing bacteria, when wastewater is treated, etc.[7]

Struvite is occasionally found in canned seafood, where its appearance is that of small glass slivers, objectionable to consumers for aesthetic reasons but of no health consequence.[8] A simple test can differentiate struvite from glass.[9]

Struvite kidney stones

Also known as triple phosphate stone (calcium magnesium ammonium phosphate).

bacterial infection that hydrolyzes urea to ammonium and raises urine pH to neutral or alkaline values. Urea-splitting organisms include Proteus, Xanthomonas, Pseudomonas, Klebsiella, Staphylococcus, and Mycoplasma
.

Even in the absence of infection, accumulation of struvite crystals in the

urinary bladder is a problem frequently seen in housecats, with symptoms including difficulty urinating (which may be mistaken for constipation) or blood in the urine (hematuria). The protein cauxin, a protein excreted in large amounts in cat urine that acts to produce a feline pheromone, has recently been found to cause nucleation of struvite crystals in a model system containing the ions necessary to form struvite. This may explain some of the excess struvite production in domestic cats.[13] In the past, surgery has been required to remove struvite uroliths in cats; today, special acidifying low magnesium diets may be used to dissolve sterile struvite stones.[14]

Upper urinary tract stones that involve the renal pelvis and extend into at least 2 calyces are classified as staghorn calculi. Although all types of urinary stones can potentially form staghorn calculi, approximately 75% are composed of a struvite-carbonate-apatite matrix.

  • Dog struvite bladder stones
    Dog struvite bladder stones
  • Struvite crystals in a human urine sample with a pH of 9. Abundant amorphous phosphate crystals, several squamous and non-squamous epithelial cells and a few leukocytes can also be observed.
    Struvite crystals in a human urine sample with a pH of 9. Abundant amorphous phosphate crystals, several squamous and non-squamous epithelial cells and a few leukocytes can also be observed.
  • Another image from the same urine sample as with the image on the left.
    Another image from the same urine sample as with the image on the left.
  • Comparison of different types of urinary crystals.
    Comparison of different types of urinary crystals.

Struvite enteroliths

Struvite is a common mineral found in enteroliths (intestinal concretions) in horses.[15]

Wastewater treatment

Struvite can be a problem in

waste water treatment plants
.

Struvite. Clogged sewer pipes

Having struvite scale in a wastewater treatment system can lead to great inefficiency within the plant or operation due to clogging of the pipes, pumps and equipment. There have been a few options to solve this issue, including replacing the pipes, or using a hydro-jetter or a mechanical grinder to clear them. But many lines can be underground and either of these options implies considerable downtime and labor. Chemical cleaning is now predominately used to clear systems of struvite. Chemical cleaning products have been developed to remove and prevent struvite with minimal downtime. Even a chemical-free, electric method of removing and preventing struvite has been developed and tested successfully at wastewater treatment plants in the USA. The electronic sine wave it produces is sent through the water in the pipe and is therefore effective on underground piping as well.[16][17][18]

Uses

See also: Reuse of human excreta § Urine

Use of struvite as an agricultural fertilizer was first described in 1857. It contains P and N, two of the three major plant macronutrients, with Mg being a minor macronutrient as well. Struvite can be produced from urine by adjusting pH (often just by waiting for urease-producing bacteria to work) and adding magnesium.[19] There is considerable interest in the utility of urine-derived struvite as a fertilizer in austere situations.[20][21]

References

Wikimedia Commons has media related to Struvite.
  1. S2CID 235729616
    .
  2. ^ "Struvite" (PDF). Handbook of mineralogy.
  3. ^ a b "Struvite Mineral Data". Webmineral.
  4. ^ "Struvite". Mindat.
  5. ^ Witty, M (2016). Hooke’s Gravel was Struvite. Notes and Queries 63(4):569–570. https://doi.org/10.1093/notesj/gjw218
  6. doi:10.1039/mp8450300106
    .
  7. PMID 33420384
    .
  8. Komo News
    . Retrieved 2016-07-21.
  9. ^ "Struvite Crystals, the facts ..." (PDF). Hambleton District Council. 6 October 2023.
  10. PMID 33760542
    , retrieved 2024-01-16
  11. PMID 351265
    .
  12. ^ "Uroliths". Shiloh Shepherd Genetic Task Force. February 2014. Archived from the original on 2012-09-14. Retrieved 2014-02-07.
  13. PMID 17976920
    .
  14. PMID 9868260
    .
  15. PMID 7251465
    .
  16. S2CID 25433506. Archived from the original
    (PDF) on 2012-03-27.
  17. ^ Hume M. "Sewage plant carries sweet smell of phosphorus". The Globe And Mail. Retrieved 2014-07-08.
  18. ^ Morton B. "Reclaiming minerals from waste water to make fertilizer". The Vancouver Sun. Retrieved 2013-06-05.
  19. S2CID 246700356
    .
  20. ^ Antonini, Samantha (2012). Nutrient recovery from human urine: Treatment options and reuse potential (PDF) (PhD). University of Bonn, DE.
  21. PMID 28409915
    .

External links
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