Struvite Control by Chemical Treatment

Buchanan, John R.; Mote, C. R.; Robinson, Robert J.

doi:10.13031/2013.28211

Cited by 30 publications

(15 citation statements)

References 0 publications

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“…In the literature, there are some papers have reported that the optimum pH range for struvite formation is 8.5-9.5 [16,17]. These results are similar range as our results.…”

Section: Fig 1: Nutrients Removal Ratio At Different Phsupporting

confidence: 92%

Chemical Precipitation of Ammonia and Phosphate from Nam Son Landfill Leachate, Hanoi

Khai¹

2012

IJEE

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Abstract:Leachate from municipal landfills of the city is often contaminated heavily, especially for parameters such as organic components, heavy metals, microorganisms. However, leachate also contains amounts of valuable nutrients (e.g. N, P, K) which can be used for agriculture as fertilizers. Precipitated of N and P in the form of struvite (MgNH 4 PO 4 .6H 2 O) might be applied as a technique for removal a huge amount of N as well as P in wastewater. This study investigated the recovery ability of N, P in leachate from Nam Son municipal landfill of Hanoi city. Different pH values, anaerobic time and stoichiometric Mg 2+ : NH 4 + : PO 4 3-was tested to determine the optimal conditions for precipitating struvite. The effect of pH on the forming of struvite was between pH 9 to 11. The results showed that nutrients in landfill leachate could be recovered with the optimum pH around 9.5 and the optimum Mg 2+ : NH 4 + : PO 4 3-molar ratio as 1.15: 1: 1. With the anaerobic interval of 21 days, COD value in landfill leachate was decreased to 60%, the retrieval reached 80.6% for nitrogen and 82.7% for phosphorus. According to estimates, with the application of struvite precipitation technique, the average annual retrieval amount of NH 4 + and PO 4 3-can reach 263 tons and 25 tons, respectively.

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“…In the literature, there are some papers have reported that the optimum pH range for struvite formation is 8.5-9.5 [16,17]. These results are similar range as our results.…”

Section: Fig 1: Nutrients Removal Ratio At Different Phsupporting

confidence: 92%

Chemical Precipitation of Ammonia and Phosphate from Nam Son Landfill Leachate, Hanoi

Khai¹

2012

IJEE

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“…In most slurries with a typical pH of 7.5-8.3, the NH ) for the formation of struvite and will not be the limiting factor in the reaction (Nelson et al, 2003). At high pH, the NH + 4 concentration will decrease, and low NH + 4 concentration may limit struvite formation (Buchanan et al, 1994). Optimal conditions for the sedimentation of struvite therefore occur at about pH 9 (Buchanan et al, 1994;Nelson et al, 2003).…”

Section: Theorymentioning

confidence: 99%

“…At high pH, the NH + 4 concentration will decrease, and low NH + 4 concentration may limit struvite formation (Buchanan et al, 1994). Optimal conditions for the sedimentation of struvite therefore occur at about pH 9 (Buchanan et al, 1994;Nelson et al, 2003).…”

Section: Theorymentioning

confidence: 99%

Solid—liquid separation of animal slurry in theory and practice. A review

Hjorth

Christensen

et al. 2010

Agron. Sustain. Dev.

335

235

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-Animal slurry contains plant nutrients that are essential for crop production. However, intensive livestock production may lead to a surplus of plant nutrients on farms and, as a consequence, discharge or emission to the environment. In order to ensure that the slurry applied to fields matches the nutrient requirements of the crops, techniques have been developed to reduce the nutrient content of slurry by means of separation. This review discusses the separation technologies used for animal slurry treatment and the physical and chemical processes involved in separation. These processes need to be understood before efficient, reliable and cheap separation technologies that take into account the actual properties of slurry and the likely end-use of the separation products can be developed. A simple separation efficiency expression can be used to assess the efficiency of slurry separation. It is indeed important to measure the amount and composition of the slurry before treatment, the dry-matter-rich fraction and the liquid fraction. The separation efficiency of mechanical separators for the removal of dry matter and phosphorus (P) is ranked as follows: centrifugation > sedimentation > non-pressurized filtration > pressurized filtration. In general, the separation of total N and NH + 4 follows the same pattern, but the separation efficiency is lower than for dry matter and P. Treatment with a flocculant before separation improves separation efficiency significantly. Of the polyacrylamide polymers tested, high-molecular-weight, linear cationic polymers with a medium charge density (20-40 mol%) were found to be the most efficient flocculants. The best mechanical separation techniques for flocculated slurry are screens or filter belts. The separation efficiency of polyacrylamide-treated slurry can be improved by adding a multivalent ion to coagulate particles and for precipitation of phosphorus. Aluminium sulfate (Al 2 (SO 4 ) 3 ) or ferric chloride (FeCl 3 ) seem to be very efficient for improving the mechanical separators. Alternatively, the mineral struvite (MgNH 4 PO 4 ) may be formed by changing the slurry characteristics, such as by the addition of magnesium (Mg) or by increasing the pH to 9. The struvite crystals are removed during solid-liquid separation. The products of the solid-liquid separation may be further treated by evaporation, membrane filtration or ammonia stripping in order to obtain the desired end-products; however, low-maintenance and/or cost-efficient operation of these post-treatments has not yet been demonstrated. The separation should be developed as a whole-system approach, paying attention to parameters such as the value of end-products, environmental consequences and economy.

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“…Buchanan et al [16] reported that MAP could be precipitated out of solution at pH 9.0. Booker et al [17] also reported the optimum pH for MAP formation was 9.0-9.4.…”

Section: Optimum Ph Experimentsmentioning

confidence: 99%