Biological nitrogen removal with enhanced phosphate uptake in (AO)2 SBR using single sludge system

IntroductionBiologicalphosphorusandnitrogenremovalprocesshasprovidedsignificantbenefitstoameliorateeutrophicationofsurfacewaterwithoutexacerbatingsalination .Recentresearchesonnitrogenremovalaremostlyeithertowardsimprovementofperformanceandenergysavingsintraditionalprocessesortowardsdevelopmentofnewprocesses microorganismsthatareabletoconvertammonium oxidatednitrogenintoharmlessforms.Shorternitrificationanddenitrification ,i.e .partialoxidationofNH 4toNO-2 andsubsequentreductionofthelatterto…     

不同氮磷营养条件下铜绿微囊藻（Microcystis aeruginosa）对正磷酸盐的蓄积效果

铜绿微囊藻是中国湖泊、水库及其它水域生态系统发生、形成富营养化危害的主要藻类。采用了直接显色法对单细胞铜绿微囊藻（〖WTBX〗Microcystis aeruginosa〖WTBZ〗）蓄积正磷酸盐的浓度进行测定,并与传统测定方法进行比较。直接显色法测定的磷浓度值减去溶液中可溶性磷浓度值即得到铜绿微囊藻蓄积的磷浓度值。对用不同处理方式处理过的铜绿微囊藻藻液进行过滤显色和直接显色测定,结果表明聚磷酸盐(正磷酸盐)在铜绿微囊藻体内不是游离存在,而很可能是与细胞内某一活性部分结合。在确立测定方法的基础上,研究了以修改了的MⅢ培养基为基本培养条件,改变氮磷浓度对产毒铜绿微囊藻（FACHB942）蓄积正磷酸盐效果的影响。结果显示,①氮磷比不变时,随着起始磷浓度的增加,铜绿微囊藻对正磷酸盐蓄积量也逐渐增加,成明显正相关;②氮浓度不变时,铜绿微囊藻对正磷酸盐的蓄积效果与磷浓度正相关;③而同一磷浓度下,铜绿微囊藻对正磷酸盐的蓄积效果与氮浓度负相关,但氮浓度超过21 mg/L时,氮浓度对于铜绿微囊藻蓄积磷的效果影响变得不规则。     

不同生存环境和磷酸盐对4株溶磷菌溶磷能力的影响

利用液体培养法研究了不同NaCl浓度、碳源、氮源、溶解氧及磷酸盐对分离自小麦(Triticum aestivum)、苜蓿(Medicago sativa)根际的4株优良溶磷细菌(Lx81、Jm92、Dm84、Lx191)溶磷能力的影响.结果表明:(1)4株溶磷菌均为高耐盐菌株,其中Jm92和Din84维持较高溶磷量的NaCl浓度最高阈值分别为4%和8%,Lx81、Lx191在NaCl浓度超过5%时溶磷活性受到抑制.(2)Lx81的最佳碳源是葡萄糖,其次为蔗糖;另外3株菌在葡萄糖和蔗糖为碳源时,均有较高的溶磷能力;4株菌都几乎不能利用淀粉.(3)Lx81和Jm92在以(NH_4)_2SO_4和NH_4 NO_3为氮源时溶磷活性均较高,(NH_4)_2SO_4 是Lx191的最佳氮源,而NH~+-N存在会导致Dm84溶磷活性降低.(4)供试4株菌均不是专性厌氧菌,但不同菌株对氧的需求量不同.(5)4株溶磷菌对Ca_3-P和Ca_8-P有较大的溶解效率,但它们几乎都不能溶解Ca_(10)-P.图3表4参14     

憎水性污染物在表面活性剂溶液中的增溶动力学

为了解表面活性剂溶液对憎水性污染物增溶过程的影响因素,研究六氯乙烷在Ｔｗｅｅｎ２０溶液中的增溶动力学过程,建立了六氯乙烷在表面活性剂溶液中增溶的传质模型．模型表明当六氯乙烷总表面积固定时,其溶解速率同六氯乙烷在表面活性剂溶液中的表观溶解度和表观传质系数呈正相关．发现六氯乙烷在表面活性剂溶液中的表观传质系数和纯水中的相比降低了,但由于表面活性剂对六氯乙烷的增溶作用导致其溶解速率总体上是提高的     

改良型A2/O-MBR工艺的反硝化除磷性能研究简

重点考察了一种改良型膜生物反应器（A²/O-MBR）的脱氮除磷性能。该工艺主要特点在于对膜池硝化回流液进行了固液分离,并将上清液和浓缩污泥分别回流至缺氧池和厌氧池,这种改进提高了系统对氮、磷的同步去除效率。实验结果表明,在水力停留时间（HRT）为12 h,污泥龄（SRT）为30 d,混合液回流比为200%的运行条件下,进水COD、NH₄⁺-N、TN和TP平均浓度分别为（225±38）、（24.8±3.9）、（26.7±2.9）和（2.90±0.53）mg/L时,增加膜池硝化回流液固液分离装置前后,系统对COD和NH₄⁺-N的去除都维持在较高水平,而系统对TN和TP的去除效果显著提高,出水TN和TP平均浓度分别由（14.9±3.3）mg/L和（1.95±0.72）mg/L下降到（9.4± 1.9）mg/L和（0.91±0.38）mg/L,表明增加膜池硝化回流液固液分离装置显著改善了A²/O-MBR系统的脱氮除磷效果。反硝化除磷活性实验结果进一步表明,改进后系统中反硝化除磷活性占总除磷活性的比例由51.5%上升至61.7%,说明增加膜池硝化回流液固液分离装置强化了系统的反硝化除磷性能。     

次氯酸钠氧化—磷酸铵镁沉淀法处理草甘膦废水并回收磷

针对草甘膦废水处理与磷回收难题,研究了次氯酸钠氧化草甘膦与磷酸铵镁沉淀法回收磷工艺的可行性。实验结果表明,次氯酸钠氧化草甘膦的最佳工艺条件为:次氯酸钠加入量109 g/L,溶液pH为9.0,氧化时间20 min。次氯酸钠氧化草甘膦的主要降解途径为:C—N键断裂生成羟基乙酸和乙酸;C—P键断裂生成磷酸(主要反应)。正交实验得到的磷酸铵镁沉淀法回收磷的最佳工艺条件为溶液pH 9.0、镁磷摩尔比1.2、氮磷摩尔比1.4、反应时间15 min,在此条件下磷酸盐回收率达99.3%。XRD图谱证实所得固体主要成分为磷酸铵镁。     

Synthesis and characteristic analysis of coal dust explosion suppressant based on surface modification of ammonium dihydrogen phosphate with methyl hydrogen-containing silicone oil

Coal dust explosion is easy to happen in the process of coal pulverization. In order to reduce the risk of coal dust explosion and promote the safety of coal chemical industry, surface modification of the ammonium dihydrogen phosphate (ADP) explosion suppressant was performed with methyl hydrogen-containing silicone oil to obtain modified ammonium dihydrogen phosphate (MADP) powder. The explosion suppression and hydrophobic properties of MADP were tested. The experimental results show that after surface modification, MADP overcomes the defect that the traditional ammonium dihydrogen phosphate explosion suppressant is easily affected by moisture, which results in agglomeration; further, MADP has little or no solubility in water and has excellent hydrophobic properties. After surface modification, MADP has better thermal stability and can withstand higher ambient temperatures. MADP can significantly increase the minimum ignition energy, thus reducing the possibility of combustion and explosion. With the increase in the mass concentration of the explosion suppressant, the maximum explosion pressure gradually decreases and delays. Compared with ADP, MADP has better explosion suppression characteristics and can quickly and efficiently suppress explosion.     

Microbial Biomass,P-Nutrition,and Enzymatic Activities of Wheat Soil in Response to Phosphorus Enriched Organic and Inorganic Manures

Compost was prepared from wheat straw enriched with Rajasthan rock phosphate and Aspergillus awamori. The resulting phospho-compost along with phosphorus enriched FYM, mineral fertilizer (rock phosphate) and super phosphate were evaluated for their individual contribution in improving organic matter status, P availability, and enzymatic activities of soil under wheat crop grown in a micro plot. The results showed that total organic carbon, nitrogen, microbial biomass, and humus content (an index of organic matter status of soil) of soil was highest when farmyard manure (FYM) after its enrichment with 12.5% rock phosphate was applied. Microbial enriched phospho-compost was the product yielding highest soil available phosphorus, phosphorus uptake, urease, and cellulase activities. However, FYM amended with 25% rock phosphate resulted in the greatest enhancement of β-glucosidase. Measured parameters indicated a sure improvement of chemical and biological activities of soil after the application of phosphorus enriched organic amendments compared to the commercial fertilizer commonly used by the Indian farmers.     

Glyphosate and AMPA of agricultural soil,surface water,groundwater and sediments in areas prevalent with chronic kidney disease of unknown etiology,Sri Lanka

Abstract

Glyphosate, which is commercially available as Roundup®, was the widely used herbicide in Sri Lanka until 2015 and is suspected to be one of the causal factors for Chronic Kidney Disease of unknown etiology (CKDu). This research, therefore, aims at studying the presence of glyphosate and Aminomethylphosphonic acid (AMPA) in different environmental matrices in CKDu prevalent areas. Topsoil samples from agricultural fields, water samples from nearby shallow wells and lakes, and sediment samples from lakes were collected and analyzed for glyphosate and AMPA using the LC/MS. Glyphosate (270–690 µg/kg) and AMPA (2–8 µg/kg) were detected in all soil samples. Amorphous iron oxides and organic matter content of topsoil showed a strong and a moderate positive linear relationship with glyphosate. The glyphosate and inorganic phosphate levels in topsoil had a strong negative significant linear relationship. Presence of high valence cations such as Fe³⁺ and Al³⁺ in topsoil resulted in the formation of glyphosate-metal complexes, thus strong retention of glyphosate in soil. Lower levels of AMPA than the corresponding glyphosate levels in topsoil could be attributed to factors such as the strong adsorption capacity of glyphosate to soil and higher LOQ in the quantification of AMPA. The glyphosate levels of lakes were between 28 to 45 µg/L; no AMPA was detected. While trace levels of glyphosate (1–4 µg/L) were detected in all groundwater samples, AMPA (2–11µg/L) was detected only in four out of nine samples. Glyphosate was detected in all sediment samples (85–1000 µg/kg), and a strong linear relationship with the organic matter content was observed. AMPA was detected (1–15 µg/kg) in seven out of nine sediment samples. It could be inferred that the impact on CKDu by the levels of glyphosate and AMPA detected in the study area is marginal when compared with the MCL of the USEPA (700 µg/L).     

利用白云石回收污泥厌氧消化液中的磷

为经济有效地从污泥厌氧消化液中回收磷,构建了以白云石提供钙镁源的磷回收方法,探讨了磷回收的工艺条件与效果。通过盐酸酸化厌氧消化液以降低其碳酸盐含量,同时利用白云石溶于冷稀盐酸的特性使其钙镁缓慢释放到酸化的厌氧消化液中形成第一步磷回收体系,考察体系酸化pH、白云石与厌氧消化液的固液比以及反应pH对白云石的钙镁释放和磷回收效果的影响;第一步磷回收后的上清液为第二步厌氧消化液磷回收提供钙镁源,研究投加钙磷摩尔比对磷回收效果的影响。实验结果表明,当固液比为5.0时,在酸化pH为4.0～4.5且酸化溶出时间为10 h以及反应pH为9.0的条件下,第一步磷回收产物以磷酸钙盐沉淀为主,厌氧消化液磷回收率及回收产物含磷率（以P2O5计）分别达到99.43%和38.49%;第一步磷回收后的上清液按一定的钙磷摩尔比投加到酸化后的厌氧消化液中进行第二步磷回收,当投加钙磷摩尔比为0.20时,在反应pH为9.0的条件下,回收产物同时含有磷酸钙盐和磷酸铵镁,厌氧消化液中氮、磷回收率分别达到13.19%和90.90%,回收产物氮、磷含量（以P2O5计）分别为0.26%和39.58%;经XRD、XRF、ICP及SEM等分析表征,2步磷回收的产物以磷酸钙盐和磷酸铵镁为主要成分,杂质少。研究表明,利用白云石为钙镁源,通过分别构建不同的磷回收体系可以分步从污泥厌氧消化液中经济有效地回收磷,且磷回收率和回收产物含磷率高。