鸟粪石沉淀法回收剩余污泥及其上清液中磷

Study on phosphorus recovery from excess sludge and supernatant by struvite precipitation

以剩余污泥为研究对象,考察了pH值和温度变化对鸟粪石沉淀法回收磷效果的影响.结果表明,回收率随着pH值的升高或降低均得到提高,在pH=3时达到最大值;在酸性或碱性条件下运行对温度具有较强的缓冲能力.采用正交试验对污泥上清液中磷进行回收,通过对极差分析得到影响回收率的条件依次为:pH值>初始磷酸盐质量浓度>nMg/nP>反应时间.最佳pH值范围9.5～10.5,但为减少挥发的氨氮含量,pH值应控制在10以下.鸟粪石沉淀法可与生物法综合利用,达到污泥处理的减量化和资源化.

Taking excess sludge as a research object, the impacts of pH and temperature on phosphorus recovery by struvite precipitation were investigated. The results showed that the recovery rates rise with the increased and decreased pH, and reach the maximum value at pH = 3. The enhancement of temperature buffer capacity was on the acidic or basic condition operation. The orthogonal experiment was taken on the phosphorus recovery from sludge su- pernatant. The impact extent of different factors on recovery ratio follows as： pH 〉 initial phosphate concentration 〉 nMs/nP 〉 reaction time by range analysis. The optimized pH range was 9.5 - 10.5. To decrease the content of volatile NH3--N, the pH condition was controlled below 10. The combination of struvite precipitation and biology technology could achieve the decreasing and resource utilization of waste sludge.