A system having a crystallization process for phosphorus recovery from methane fermentation digested sludge

Kazuaki Shimamura, Tateki Kurosawa, Izumi Hirasawa

    Research output: Contribution to journalArticle

    Abstract

    Methane fermentation treatment of solids yields a digested sludge containing nitrogen and phosphorus in high concentrations. For the purposes of phosphorus load reduction of the water treatment system, anti-scaling of methane fermentation tanks and their surrounding apparatus, and phosphorus resource recovery, a system for positive crystallization and recovery of magnesium ammonium phosphate (MAP) from the digested sludge was devised. This system consists of a crystallization process, a separation process using the hydrocyclone and a low temperature drying process. The optimum operational conditions for MAP and the MAP drying conditions for a digested sludge containing solids at a concentration of several per cent were clarified, and a pilot-scale plant having a treatment capacity of 2 m3/h was built and subjected to 16-month demonstration tests. For the separation of MAP using the hydrocyclone, it is necessary to suppress nucleation in the crystallization process. Based on the laboratory tests, it was found that MAP nucleation is suppressed and the crystal growth becomes predominant when a good fluidized condition of MAP is maintained in the reactor, the reactor is operated at a low supersaturation degree, and a suitable MAP crystallization loading per charged seed crystal amount is maintained. It was also found that, in the drying process, MAP can maintain its form without transition when the drying temperature is set below 70oC. In the demonstration tests of the series of processes, the PO4-P removal efficiency in the crystallization process was above 85%, showing that the reactions proceeded well. Moreover, only about 10% of the reacted phosphorus was nucleated; that is, about 90% of reacted phosphorus grew on the seed crystal surfaces, and as a result, MAP could be separated well from the digested sludge. MAP recovered from the drying process had a moisture content below 0.1%, a purity of 92.6%, and a hazardous metal content below the standard values prescribed by the Fertilizer Regulation Act, and therefore, it could be confirmed that MAP has a high quality as a fertilizer product.

    Original languageEnglish
    Pages (from-to)127-132
    Number of pages6
    JournalKagaku Kogaku Ronbunshu
    Volume35
    Issue number1
    DOIs
    Publication statusPublished - 2009

    Fingerprint

    Methane
    Crystallization
    Fermentation
    Phosphorus
    Magnesium
    Phosphates
    Recovery
    Drying
    Fertilizers
    Low temperature drying
    ammonium phosphate
    Nucleation
    Demonstrations
    Crystals
    Supersaturation
    Water treatment
    Crystal growth
    Nitrogen
    Moisture
    Metals

    Keywords

    • Crystallization
    • Digested sludge
    • Hydrocyclone
    • Magnesium ammonium phosphate
    • Phosphorus recovery

    ASJC Scopus subject areas

    • Chemical Engineering(all)
    • Chemistry(all)

    Cite this

    A system having a crystallization process for phosphorus recovery from methane fermentation digested sludge. / Shimamura, Kazuaki; Kurosawa, Tateki; Hirasawa, Izumi.

    In: Kagaku Kogaku Ronbunshu, Vol. 35, No. 1, 2009, p. 127-132.

    Research output: Contribution to journalArticle

    @article{c2f707f9045c4fc89a49a683e693b90d,
    title = "A system having a crystallization process for phosphorus recovery from methane fermentation digested sludge",
    abstract = "Methane fermentation treatment of solids yields a digested sludge containing nitrogen and phosphorus in high concentrations. For the purposes of phosphorus load reduction of the water treatment system, anti-scaling of methane fermentation tanks and their surrounding apparatus, and phosphorus resource recovery, a system for positive crystallization and recovery of magnesium ammonium phosphate (MAP) from the digested sludge was devised. This system consists of a crystallization process, a separation process using the hydrocyclone and a low temperature drying process. The optimum operational conditions for MAP and the MAP drying conditions for a digested sludge containing solids at a concentration of several per cent were clarified, and a pilot-scale plant having a treatment capacity of 2 m3/h was built and subjected to 16-month demonstration tests. For the separation of MAP using the hydrocyclone, it is necessary to suppress nucleation in the crystallization process. Based on the laboratory tests, it was found that MAP nucleation is suppressed and the crystal growth becomes predominant when a good fluidized condition of MAP is maintained in the reactor, the reactor is operated at a low supersaturation degree, and a suitable MAP crystallization loading per charged seed crystal amount is maintained. It was also found that, in the drying process, MAP can maintain its form without transition when the drying temperature is set below 70oC. In the demonstration tests of the series of processes, the PO4-P removal efficiency in the crystallization process was above 85{\%}, showing that the reactions proceeded well. Moreover, only about 10{\%} of the reacted phosphorus was nucleated; that is, about 90{\%} of reacted phosphorus grew on the seed crystal surfaces, and as a result, MAP could be separated well from the digested sludge. MAP recovered from the drying process had a moisture content below 0.1{\%}, a purity of 92.6{\%}, and a hazardous metal content below the standard values prescribed by the Fertilizer Regulation Act, and therefore, it could be confirmed that MAP has a high quality as a fertilizer product.",
    keywords = "Crystallization, Digested sludge, Hydrocyclone, Magnesium ammonium phosphate, Phosphorus recovery",
    author = "Kazuaki Shimamura and Tateki Kurosawa and Izumi Hirasawa",
    year = "2009",
    doi = "10.1252/kakoronbunshu.35.127",
    language = "English",
    volume = "35",
    pages = "127--132",
    journal = "Kagaku Kogaku Ronbunshu",
    issn = "0386-216X",
    publisher = "Society of Chemical Engineers, Japan",
    number = "1",

    }

    TY - JOUR

    T1 - A system having a crystallization process for phosphorus recovery from methane fermentation digested sludge

    AU - Shimamura, Kazuaki

    AU - Kurosawa, Tateki

    AU - Hirasawa, Izumi

    PY - 2009

    Y1 - 2009

    N2 - Methane fermentation treatment of solids yields a digested sludge containing nitrogen and phosphorus in high concentrations. For the purposes of phosphorus load reduction of the water treatment system, anti-scaling of methane fermentation tanks and their surrounding apparatus, and phosphorus resource recovery, a system for positive crystallization and recovery of magnesium ammonium phosphate (MAP) from the digested sludge was devised. This system consists of a crystallization process, a separation process using the hydrocyclone and a low temperature drying process. The optimum operational conditions for MAP and the MAP drying conditions for a digested sludge containing solids at a concentration of several per cent were clarified, and a pilot-scale plant having a treatment capacity of 2 m3/h was built and subjected to 16-month demonstration tests. For the separation of MAP using the hydrocyclone, it is necessary to suppress nucleation in the crystallization process. Based on the laboratory tests, it was found that MAP nucleation is suppressed and the crystal growth becomes predominant when a good fluidized condition of MAP is maintained in the reactor, the reactor is operated at a low supersaturation degree, and a suitable MAP crystallization loading per charged seed crystal amount is maintained. It was also found that, in the drying process, MAP can maintain its form without transition when the drying temperature is set below 70oC. In the demonstration tests of the series of processes, the PO4-P removal efficiency in the crystallization process was above 85%, showing that the reactions proceeded well. Moreover, only about 10% of the reacted phosphorus was nucleated; that is, about 90% of reacted phosphorus grew on the seed crystal surfaces, and as a result, MAP could be separated well from the digested sludge. MAP recovered from the drying process had a moisture content below 0.1%, a purity of 92.6%, and a hazardous metal content below the standard values prescribed by the Fertilizer Regulation Act, and therefore, it could be confirmed that MAP has a high quality as a fertilizer product.

    AB - Methane fermentation treatment of solids yields a digested sludge containing nitrogen and phosphorus in high concentrations. For the purposes of phosphorus load reduction of the water treatment system, anti-scaling of methane fermentation tanks and their surrounding apparatus, and phosphorus resource recovery, a system for positive crystallization and recovery of magnesium ammonium phosphate (MAP) from the digested sludge was devised. This system consists of a crystallization process, a separation process using the hydrocyclone and a low temperature drying process. The optimum operational conditions for MAP and the MAP drying conditions for a digested sludge containing solids at a concentration of several per cent were clarified, and a pilot-scale plant having a treatment capacity of 2 m3/h was built and subjected to 16-month demonstration tests. For the separation of MAP using the hydrocyclone, it is necessary to suppress nucleation in the crystallization process. Based on the laboratory tests, it was found that MAP nucleation is suppressed and the crystal growth becomes predominant when a good fluidized condition of MAP is maintained in the reactor, the reactor is operated at a low supersaturation degree, and a suitable MAP crystallization loading per charged seed crystal amount is maintained. It was also found that, in the drying process, MAP can maintain its form without transition when the drying temperature is set below 70oC. In the demonstration tests of the series of processes, the PO4-P removal efficiency in the crystallization process was above 85%, showing that the reactions proceeded well. Moreover, only about 10% of the reacted phosphorus was nucleated; that is, about 90% of reacted phosphorus grew on the seed crystal surfaces, and as a result, MAP could be separated well from the digested sludge. MAP recovered from the drying process had a moisture content below 0.1%, a purity of 92.6%, and a hazardous metal content below the standard values prescribed by the Fertilizer Regulation Act, and therefore, it could be confirmed that MAP has a high quality as a fertilizer product.

    KW - Crystallization

    KW - Digested sludge

    KW - Hydrocyclone

    KW - Magnesium ammonium phosphate

    KW - Phosphorus recovery

    UR - http://www.scopus.com/inward/record.url?scp=70249112648&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=70249112648&partnerID=8YFLogxK

    U2 - 10.1252/kakoronbunshu.35.127

    DO - 10.1252/kakoronbunshu.35.127

    M3 - Article

    VL - 35

    SP - 127

    EP - 132

    JO - Kagaku Kogaku Ronbunshu

    JF - Kagaku Kogaku Ronbunshu

    SN - 0386-216X

    IS - 1

    ER -