Municipal digested sludge (MDS) has considerable phosphorus content that is between 1% and 15% in dry matter and it is a potential source for phosphorus recovery. A high amount of MDS is generated from sewage treatment plants in large cities and has many environmental concerns with its organic and inorganic constituents. In this study, phosphorus was recovered by precipitation with Ca(OH)₂ and NaOH. Acid pretreatment was applied to MDS with H₂SO₄ and 58.7% of phosphorus was extracted from the solid phase to the liquid phase at pH 2. Up to 99% of dissolved phosphorus in the liquid phase was recovered with Ca(OH)₂ and NaOH. Almost similar phosphorus precipitation rates were achieved with both bases but higher phosphorus contents (17% as P₂O₅) in precipitates were obtained by NaOH. The product obtained in this study can serve as a high-quality raw material substitute for the low-grade phosphate rocks (<15% P₂O₅) commonly utilized in the phosphate industry. Furthermore, this research presents a practical, environmentally friendly and cost-effective approach for sustainable sludge management and phosphorus production.

中文翻译：

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酸碱沉淀从城市消化污泥中回收磷

城市消化污泥 (MDS) 的磷含量相当高，干物质含量在 1% 至 15% 之间，是磷回收的潜在来源。大城市的污水处理厂产生大量MDS，其有机和无机成分存在许多环境问题。在本研究中，通过用 Ca(OH) ₂和 NaOH 沉淀来回收磷。_{用 H 2} SO ₄对 MDS 进行酸预处理，在 pH 2 时将 58.7% 的磷从固相萃取到液相。用 Ca(OH) ₂回收液相中高达 99% 的溶解磷，并回收氢氧化钠。两种碱获得了几乎相似的磷沉淀率，但通过NaOH获得了沉淀物中更高的磷含量（以P ₂ O _{5计为17%）。}本研究获得的产品可以作为磷酸盐工业中常用的低品位磷矿（<15% P ₂ O _{5 ）的优质原料替代品。}此外，这项研究还提出了一种实用、环保且具有成本效益的可持续污泥管理和磷生产方法。