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Abstract Phosphorus in the residual sludge is an important reusable resource. In order to solve the technical problem of phosphorus release from the residual sludge, a self-developed square internal circulation ozone fluidized bed unit was used to explore the controlling factors of phosphorus release from the residual sludge and reveal the release mechanism of phosphorus. The results showed that when the intake concentration was 3.0 g·L-1, pH 9.1, and the operating time was 1.0 h, the release of phosphorus gradually stabilized, and the release mass of total phosphorus reached about 6.9 g/L of residual sludge (containing 5% solids), accounting for 77.5% of the mass fraction of phosphorus in the sludge, of which the mass of inorganic phosphorus accounted for 41.1%. The phosphorus speciation analysis method (SMT) was used to analyze the distribution characteristics of all forms of phosphorus, and it was found that the phosphorus released was mainly in the form of inorganic phosphorus, mainly in the form of apatite. The release mass concentration of organophosphorus increased first and then decreased, and all forms of nitrogen in the residual sludge were also released. The ozone fluidized bed unit can provide a new method for phosphorus release from residual sludge.
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Received: 15 July 2021
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2021, Vol. 34 
