【作者】 罗璟；

【导师】 王涛；

【作者基本信息】 重庆大学 ， 环境工程， 2010， 硕士

【摘要】 鸟粪石沉淀法可以同时回收污水中的氮、磷两种元素,而且本身是一种高效缓释复合肥料,因此近年来这一技术受到普遍关注。本文主要根据三峡库区城市污水水质情况,结合旁路污泥减量工艺,利用鸟粪石结晶法来去除回收污水中的氮磷。本试验研究主要分为两个部分:一是根据三峡库区城市污水水质特点配制氮磷废水,进行单因素烧杯试验。主要讨论了反应体系的pH值、三种构晶离子的摩尔配比、反应时间和反应强度等因素对鸟粪石的形成和氮磷去除效果的影响;二是将旁路污泥减量工艺模型的厌氧池中的污水作为原水,按照烧杯试验中所得的最佳参数设置并进行试验。试验结果表明,在温度、反应时间和搅拌强度一定的条件下,PO 34?的初始浓度较低时,pH值要调节至10.0左右才有明显结晶生成,并且反应较慢。反应前后的pH变化值一定程度上反映了反应程度,变化越大,说明反应进行越彻底。pH值调节至9.0左右时,生成的鸟粪石结晶体呈斜方晶;当pH值大于10.5时,生成的晶体比较细小,甚至结块。从X射线衍射图谱可以看出,pH值在9.5左右,生成物具有明显的晶体特征。同时,PO 34?初始浓度为1mmol/L(31mg/L)的水样,pH值在10.0到10.5的范围内,c(Mg 2 +): c(NH 4+ ): c(PO 34? )为1:1:1时,均可达到50%左右。若c(Mg 2 +): c(NH4+ ): c(PO 34? )为1.5:1.6:1时,鸟粪石除磷效果最佳,PO 34?去除率在55%左右,而氨氮去除率可达37%;PO 34?初始浓度为2mmol/L(62mg/L)的水样,c(Mg 2 +): c(NH +4 ): c(PO 34? )为1:1:1时,pH值取9.5最佳,磷去除率最高可达75%,氮去除率可达85%。若c(Mg 2 +): c(NH+4 ): c(PO 34? )为1.5:2.0:1时,鸟粪石除磷脱氮效果最佳,PO 34?去除率在80%左右,氨氮去除率在48%左右。此外,反应时间和搅拌强度对鸟粪石除磷脱氮效果的影响都不显著,我们在选择这两个参数的最佳值时,应该从鸟粪石的生成形态和自然沉降回收来考虑。本文认为最佳反应时间为25min,沉淀时间为60min,最佳搅拌速度为200r/min。旁路污泥减量工艺模型的厌氧池水试验研究表明,NH+4去除率约为48.5%,比配水试验相同试验条件下的NH4+去除率要高。其原因可能是由于采用污泥减量工艺中厌氧池污水,水环境比较复杂,虽然试验污水选取的是上清液,但是溶液中仍然会残留一些其他物质,如硝化菌等将NH+4转化为NO3?、NO2?或其他含氮物质。PO 34?去除率为75%,基本与配水试验中相同条件下得出的结果一致。由以上试验结果可知,利用鸟粪石结晶法去除厌氧池上清液的氮磷含量是可行的。最后,本论文对鸟粪石沉淀法回收氮磷技术进行了社会、环境和经济等方面的分析评价,得出鸟粪石结晶沉淀法具有较好的发展前景和实用价值。更多还原

【Abstract】 Struvite precipitation can simultaneously recycle two elements of nitrogen and phosphorus in sewage, and itself is an effective slow-release compound fertilizer, therefore, this technology attracts universal attention in recent years. The thesis is mainly based on municipal sewage quality situation of Three Gorges Reservoir area on the Yangtze River, incorporating with by-pass sludge reduction technology, about using struvite crystallization method remove and recycle nitrogen and phosphorus in sewage. This experimental research included two parts: on one hand, according to municipal sewage quality features of Three Gorges Reservoir area on the Yangtze River preparing nitrogen and phosphorus sewage, implemented single-factor beaker test, which mainly discussed pH value of reaction system; molar ratio of three ions to form the crystal; the influence of factors like reaction time and intensity etc. to the struvite formation and nitrogen and phosphorus removal effect. On the other hand, took the sewage in by-pass sludge reduction technology model anaerobic tank as raw water, then set up and experimented as per optimum parameter of the beaker test.Experiment result shows: in certain condition of temperature, reaction time and stirring intensity, when PO 34? initial concentration is low, pH value adjusting to 10.0 more or less, there is crystal formation, and the reaction is slow. Change of pH value before and after reaction to a certain degree reflects the reaction degree. The bigger the change is, the more thoroughly the reaction is. When pH value adjusts to about 9.0, the struvite formed is prismatic crystal; when pH value is over 10.5, the struvite formed is small, even lumped. We can see from X-ray spectrum, while pH value is around 9.5, formation substance has significant crystal characteristics. Meanwhile, water sample with PO 34? initial concentration of 1mmol/L(31mg/L), whose pH value is in the range of 10.0 to 10.5, or c(Mg 2 +): c(NH4+ ): c(PO 34? ) is 1:1:1, either can reach about 50%. If c(Mg 2 +): c(NH 4+ ): c(PO 34? ) is 1.5:1.6:1, struvite removing phosphorus effect is the best. PO4 3? removal ratio is about 55%, and ammonia-nitrogen removal ratio can reach 37%;water sample with PO 34? initial concentration of 2mmol/L(62mg/L), whose c(Mg 2 +): c(NH4+ ): c(PO 34? ) is 1:1:1, pH value 9.5 is the best, Max phosphorus removal ratio can reach as high as 75%,nitrogen removal ratio can reach 85%. If c(Mg 2 +): c(NH+4 ): c(PO 34? ) is 1.5:2.0:1, struvite P and N Removals effect is the best PO4 3? removal ratio is about 80% ammonia-nitrogen removal ratio is about 48%. Otherwise, neither reaction time nor stirring intensity influence to struvite P and N Removals effect is obvious. While choosing optimum value of these two parameters we shall consider struvite formation shape and nature precipitation recycling. Thesis considers the optimum reaction time is 25min,precipitation time is 60min,optimum stirring speed is 200r/min。By-pass sludge reduction technology model’s anaerobic tank water experiment express that NH +4 removal ratio is 48.5%, which is higher than NH 4+ removal ratio of the prepared water in the same condition. The reason may be semi real sewage was adopted, whose water environment was complex, though testing sewage was supernatant, there still would left some other substance, like nitrifying bacteria etc. changing NH 4+ to NO 3?、NO 2? or other substance which including nitrogen. PO 34? removal ratio was 75%, basically conformed to the result prepared water experiment in the same conditions. The mentioned experiment result tells using struvite crystallization method remove nitrogen and phosphorus content in anaerobic tank supernatant is feasible.At last, the thesis analysis and evaluate the technology of struvite precipitation method recycling nitrogen and phosphorus in the aspects of social, environmental and economic. And find out struvite precipitation method has excellent development prospects and practical value.更多还原