磷酸钙盐法回收剩余污泥超声波处理上清液中磷的研究

在污泥减量化处理中,细胞微生物中的碳氮磷等会释放到上清液中。为了对上清液中的磷进行有效回收,在前期研究的基础上,以生物厌氧好氧除磷(An/O)工艺的剩余污泥超声波处理上清液为研究对象,考察了磷酸钙盐(HAP)法的磷回收效果。结果表明:HAP法反应较快,5 min时反应基本完成;初始pH值在8.5～10.0时,回收率均可保持在较高水平;最佳钙磷比(Ca2+/PO34--P)为3.87。在以上最佳工艺条件下,总磷(TP)、正磷酸盐(PO34--P)的回收率分别达到88.4%、94.0%,同时对上清液中的有机物、氮也有一定的去除。

Study on phosphorus recovery by calcium phosphate precipitation from sonicated waste activated sludge supernatanlogt

There exists a large amount of phosphorus in waste activated sludge(WAS) produced from municipal wastewater treatment plants.During the reduction of WAS by sludge disintegration such as sonication etc.along with floc disintegration and cell lysis,many organic,nitrogen and phosphorus constituents of WAS would be dissolved and released into sludge supernatanlogt.Recycling of the sonicated WAS by chemical precipitation would not increase the phosphorus loading to the existing wastewater treatment system,at the same time it would be beneficial to recycle and reuse of WAS and alleviate phosphorus resources shortage of the world.The previous study on WAS sonication treatment has shown that phosphorus could be released into the supernatanlogt during the sonication treatment.Calcium phosphate precipitation(HAP),is one of the widely used chemical techniques of recovering phosphorus from the wastewater or the sludge.In this paper,a bench test on phosphorus recovery from sonicated WAS supernatanlogt by HAP was carried out.The WAS with higher concentration of phosphorus was collected from biological anaerobic oxic units which had been cultivated with simulated municipal wastewater in the lab.Through series of single factor experiments,the optimal treatment condition was obtained.The HAP reaction was very fast and almost completed in 5 min;the recovery rate of phosphorus remained at a high level when the optimum initial pH value was maintained in the range of 8.5-10.0;the optimum molar ratio of Ca2+ to PO3-4P was 3.87.Under the optimal condition mentioned above,the recovery rates of TP and PO3-4-P reached 88.4% and 94.0% respectively by HAP.Meanwhile partial nitrogen and organics in the sludge sonicated supernatanlogt were also removed.All of the tests have been carried out at room temperature.The results of study proved that phosphorus of sonicated WAS supernatanlogt could be recovered efficiently by using HAP.