【摘要】：氮磷的大量排放一方面導(dǎo)致水體污染,另一方面導(dǎo)致磷資源的流失。磷酸銨鎂法作為目前從廢水中回收氮磷最有效的途徑之一,得到了廣泛的研究。磷酸銨鎂法應(yīng)用于污水處理的限制因素主要包括兩點(diǎn),一是投加鎂源而增加的處理費(fèi)用;二是由于磷酸銨鎂法是物化方法,對(duì)氮磷濃度較低的廢水處理效果較差。如何提高磷酸銨鎂法對(duì)較低濃度氮磷廢水的處理效果是目前研究的難點(diǎn)和關(guān)鍵。本文在分別研究了Mg Cl2·6H2O溶液、Mg SO4溶液、Mg O固體和(Mg CO3)4·Mg(OH)2·5 H2O固體作為外加鎂源所需要的最佳反應(yīng)條件的基礎(chǔ)上,考察了磷酸銨鎂法用于去除高氮低磷污水中的正磷酸鹽的可行性,同時(shí)綜合考慮處理效果和經(jīng)濟(jì)因素得出最佳的鎂源;重點(diǎn)研發(fā)了用于磷酸銨鎂法脫氮除磷的一體化流化床反應(yīng)器,在研究流化床反應(yīng)器的最佳運(yùn)行參數(shù)的基礎(chǔ)上,通過實(shí)驗(yàn)比較驗(yàn)證了流化床反應(yīng)器采用磷酸銨鎂法對(duì)低濃度氮磷污水去除效果的強(qiáng)化效能,研究得出如下主要結(jié)論:(1)單因素實(shí)驗(yàn)結(jié)果表明,Mg Cl2·6H2O溶液和(Mg CO3)4·Mg(OH)2·5H2O固體作為最好的可溶性鎂源和難溶性鎂源,最佳的反應(yīng)條件分別是p H=10.5,攪拌30min,攪拌速度為100r/min,n(Mg)∶n(N)=1.1,n(P)∶n(N)=1.0;p H=8,攪拌1.5h,攪拌速度為120r/min,n(Mg)∶n(N)=1.3,n(P)∶n(N)=1.0;對(duì)應(yīng)的氨氮、正磷酸鹽的去除率分別為82%、92%和80%、84%。(2)氨氮和正磷酸鹽的進(jìn)水濃度分別為100 mg/L和70 mg/L是磷酸銨鎂法所需要的較小濃度,分別投加Mg Cl2·6H2O溶液和(Mg CO3)4·Mg(OH)2·5H2O固體作為鎂源,并在兩種鎂源各自的最佳控制條件下進(jìn)行反應(yīng),氨氮和正磷酸鹽的去除率分別為30.5%、80.6%和25.0%、73.3%。雖然投加Mg Cl2·6H2O溶液的氮磷去除效果略好于投加堿式碳酸鎂固體,但投加Mg Cl2·6H2O溶液會(huì)造成二次污染,并且需要更高的p H值等因素,選擇堿式碳酸鎂作為最佳鎂源。實(shí)驗(yàn)結(jié)果也證明以磷酸銨鎂的形式去除高氮低磷污水中的正磷酸鹽,是可行的。(3)以(Mg CO3)4·Mg(OH)2·5 H2O固體為鎂源,設(shè)計(jì)p H值、氨氮濃度、正磷酸鹽濃度的三因素三水平正交實(shí)驗(yàn),結(jié)果表明,影響氮磷去除率的因素的主次順序?yàn)?p H值正磷酸鹽濃度氨氮濃度,綜合考慮氨氮和正磷酸鹽的去除率,選擇p H=9,N=200mg/L,P=50mg/L做為正交實(shí)驗(yàn)的最優(yōu)組合。(4)以(Mg CO3)4·Mg(OH)2·5 H2O固體為鎂源,用一體化流化床反應(yīng)器處理模擬氮磷污水,實(shí)驗(yàn)結(jié)果表明HRT越小,正磷酸鹽的去除率越大,隨著反應(yīng)時(shí)間的推移,不同HRT對(duì)應(yīng)的正磷酸鹽的去除率逐漸接近,選擇HRT=10min做為流化床反應(yīng)器的最佳水力停留時(shí)間。(5)與實(shí)驗(yàn)室小試實(shí)驗(yàn)相比,雖然由于流化床反應(yīng)器中水流的作用破壞后期形成的較大磷酸銨鎂晶粒,導(dǎo)致流化床反應(yīng)器對(duì)氮磷去除率的優(yōu)勢(shì)只體現(xiàn)在在反應(yīng)開始后的前30分鐘,但是流化床反應(yīng)器取樣位置越低,顆粒粒徑越大、沉降性能越好,并且都大于同條件下燒杯對(duì)比實(shí)驗(yàn)的顆粒粒徑。
[Abstract]:On the one hand, the discharge of nitrogen and phosphorus leads to water pollution, on the other hand, it leads to the loss of phosphorus resources. Magnesium ammonium phosphate process, as one of the most effective ways to recover nitrogen and phosphorus from wastewater, has been widely studied. The limiting factors of magnesium ammonium phosphate process in wastewater treatment mainly include two points, one is the increased cost of adding magnesium source, the other is that magnesium ammonium phosphate method is a physicochemical method, and the effect of magnesium ammonium phosphate method on wastewater treatment with low concentration of nitrogen and phosphorus is poor. How to improve the treatment effect of magnesium ammonium phosphate process on low concentration nitrogen and phosphorus wastewater is the difficulty and key of current research. In this paper, the optimum reaction conditions for Mg Cl2 路6H2O solution, Mg SO4 solution, Mg O solid and (Mg CO3) 4 Mg (OH) 2 路5H2O solid as added magnesium source have been studied. The feasibility of removing orthophosphate from high nitrogen and low phosphorus wastewater by magnesium ammonium phosphate method was investigated, and the best magnesium source was obtained by considering the treatment effect and economic factors. An integrated fluidized bed reactor for nitrogen and phosphorus removal by magnesium ammonium phosphate method was developed. On the basis of studying the optimum operating parameters of the fluidized bed reactor, The enhancement efficiency of ammonium magnesium phosphate method for the removal of low concentration nitrogen and phosphorus wastewater in fluidized bed reactor was verified by experiments. The main conclusions are as follows: (1) the single factor experimental results show that, Mg Cl2 路6H2O solution and (Mg CO3) 4 Mg (OH) 2 路5H2O solid were the best soluble magnesium and insoluble magnesium sources. The optimum reaction conditions were pH 10.5, stirring for 30 min and stirring speed of 100 r / min, respectively. N (Mg): n (N) = 1.1, n (P): n (N) = 1.0; PH 鈮，

本文編號(hào)：2478581