羟胺抑制协同pH调控对人工快渗系统短程硝化的影响

针对人工快渗系统(CRI)总氮去除率低的问题,研究了羟胺抑制协同pH调控对人工快渗系统实现由全程硝化向短程硝化转化的可行性,探讨了其对系统内氮素污染物迁移转化和硝化功能菌空间分布及活性的影响.结果表明,0.5 mmol·L~(-1)羟胺连续添加13 d后可实现CRI系统短程硝化的快速启动,氨氮去除率、亚硝氮积累率分别为91.1%、77.9%,经16 d不添加羟胺运行后氨氮去除率、亚硝氮积累率分别降低3.9%、9.8%,此时调控进水pH至8.4,氨氮去除率和亚硝氮积累率均超过90%,CRI系统短程硝化效果显著且稳定性较高.羟胺对硝化菌具有选择性抑制,对AOB和NOB产生明显抑制的浓度分别为0.7、0.5 mmol·L~(-1),羟胺浓度为1.0 mmol·L~(-1)时AOB和NOB活性均被严重抑制且解抑较难;pH调控对短程硝化的影响主要与游离氨(FA)的抑制作用有关,对AOB和NOB产生明显抑制的FA浓度分别为26.5、5.6 mg·L~(-1),NOB比AOB对FA的敏感性更高.     

氯盐阻化剂对煤自燃极限参数影响的试验研究

阻化技术是防治煤自燃的常用技术之一,研究阻化剂对煤自燃极限参数的影响是确定阻化效果的关键.采用程序升温试验,分析气煤和长焰煤的原煤样和经MgCl2、KCl、CaCl2、NaCl 4种阻化剂处理后的煤样耗氧速率和放热强度,并计算自燃极限参数和阻化率.结果表明:氯盐阻化剂可降低煤自燃低温阶段的煤耗氧速率和放热强度;4种阻化剂中对气煤煤样的平均阻化率最高是MgCl2 (63.6％),对长焰煤则是CaCl2 (45.9％),平均阻化率与自燃极限参数变化率呈正相关;气煤经MgCl2处理后自燃极限参数变化率最大,长焰煤经CaCl2阻化处理后的自燃极限参数变化率最大,对于气煤4种阻化剂阻化能力由大到小为MgCl2 KCl、CaCl2、NaCl,对长焰煤则为CaCl2、MgCl2、KCl、NaCl;氯盐阻化剂中MgCl2对气煤自燃极限参数影响最大,阻化效果好,而对长焰煤则为CaCl2.     

晚期垃圾渗滤液短程硝化生物动力学研究

通过对亚硝化反应器中的氨氮、亚硝酸盐氮变化趋势的试验研究,认为渗滤液中存在着可以转化成氨氮的有机氮,但有机氮的转化不是在瞬时完成的。利用劳伦斯-麦卡蒂模式求得模型参数为氨氮vmax=4.67 mg/(mg.d),Ks=464.4 mg/L,Y=0.1966 mg/mg,Kd=0.55384/d,通过模型得出了反应器内生物量浓度、出流水质与污泥龄的关系,以期为实际工程中垃圾渗滤液生物脱氮提供借鉴。     

Effects of urea and (NH4)2SO4 on nitrification and acidification of Ultisols from Southern China

The mechanisms for the effects of ammonium-based fertilizers on soil acidification in subtropical regions are not well understood. Two Ultisols collected from cropland and a tea garden in Anhui and Jiangxi Provinces in subtropical southern China, respectively, were used to study the effects of urea and (NH₄)₂SO₄ on the nitrification and acidification of soils with incubation experiments. Nitrification occurred at very low pH with no N fertilizer added and led to lowering of the soil pH by 0.53 and 0.30 units for the soils from Jiangxi and Anhui, respectively. Addition of urea accelerated nitrification and soil acidification in both Ultisols; while nitrification was inhibited by the addition of (NH₄)₂SO₄, and greater input of (NH₄)₂SO₄ led to greater inhibition of nitrification. Ammonia-oxidizing bacteria (AOB) played an important role in nitrification in cropland soil under acidic conditions. Addition of urea increased the soil pH at the early stages of incubation due to hydrolysis and stimulated the increase in the AOB population, and thus accelerated nitrification and soil acidification. At the end of incubation, the pH of Ultisol from Jiangxi had decreased by 1.25, 1.54 and 1.84 units compared to maximum values for the treatments with 150, 300 and 400 mg/kg of urea-N added, respectively; the corresponding figures were 0.95, 1.25 and 1.69 for the Ultisol from Anhui. However, addition of (NH₄)₂SO₄ inhibited the increase in the AOB population and thus inhibited nitrification and soil acidification. Soil pH for the treatments with 300 and 400 mg/kg of (NH₄)₂SO₄-N remained almost constant during the incubation. AOB played an important role in nitrification of the cropland soil under acidic conditions. Addition of urea stimulated the increase in the AOB population and thus accelerated nitrification and soil acidification; while addition of (NH₄)₂SO₄ inhibited the increase in the AOB population and thus inhibited nitrification.     

Effect of wastewater COD/N ratio on aerobic nitrifying sludge granulation and microbial population shift

The effect of COD/N ratio on the granulation process and microbial population succession was investigated. Four identical sequencing batch reactors, R1, R2, R3 and R4, were operated with various initial COD/N ratios ranging from 0/200 to 800/200 (m/m). Ethanol was fed as the source of COD. Aerobic granules were successfully cultivated in R2 and R3, operating with the COD/N ratio of 200/200 and 400/200, respectively. Scanning electron microscope observations indicated that short rod-shaped and spherical bacteria were dominant in R2, while granules produced in R3 were surrounded with a large amount of filamentous bacteria. The average specific nitritation rate in R2 and R3 were 0.019 and 0.008 mg N/(mg MLVSS.hr), respectively. Fluorescence in situ hybridization results demonstrated that nitrifying bacteria population was enriched remarkably in R2. It indicated that nitrification ability and nitrifying bacteria population were enriched remarkably at low COD/N ratio. However, no granules were formed in R1 and R4 which might attribute to either limited or excessive extracellular polymeric substances production. This study contributed to a better understanding of the role of COD/N ratio in nitrifying sludge granulation.     

生物甲烷抑制剂缓释扩散模型推导与优化

以石蜡和松香为缓释基质,以碳化钙为生物甲烷抑制材料,对有效抑制组分——乙炔的扩散规律进行了研究.以T.Higuchi方程为基础,针对复杂基质的气体缓释进行了修正,得到缓释抑制剂的扩散机制模型,该模型可以有效预测乙炔的扩散系数De.同时考察了基质优化对扩散系数的影响,如果缓释基质的硬度不够,碳化钙与水反应产生的热量可导致缓释抑制剂内部膨胀从而影响缓释效果.当基质中松香的质量分数为20%,基质与碳化钙的质量比为1/1时,缓释基质的硬度和致密度提高,乙炔的扩散系数达到2.2849×10-8cm2/min(R2=0.9901),该缓释抑制剂可以有效地解决生活垃圾填埋场等人为源生物甲烷的减排问题.     

水体颗粒物对有机氮转化的影响

以多泥沙河流黄河为例,采用微宇宙实验模拟研究自然水体中有机氮的转化过程和添加人工富集的黄河优势菌种条件下的有机氮转化过程.结果表明,自然水体条件下颗粒物对有机氮的转化有明显的促进作用,转化速率常数随颗粒物含量的增加而增加,用一级动力学拟合有机氮的转化过程发现,当有机氮的初始浓度为5 mg/L,颗粒物含量分别为0、5、10 　g/L时,转化速率常数分别为0.286、0.333、0.538 d^-1,用Logistic模型对硝化过程进行模拟,硝化速率常数K₄分别为0.001 8、0.003 8,0.005 0 L·(d·μmol)^-1.在添加人工富集微生物条件下,微生物初始数量一致,体系有机氮的转化速率常数和硝化速率常数K₄均随颗粒物含量的增加而增加.水体颗粒物对有机氮转化的影响机理是：①颗粒物含量不同的水体其初始微生物数量不同,颗粒物含量越高,微生物数量也越大;②颗粒物对微生物生长有促进作用,微生物亦主要存在于颗粒物表面,且颗粒物的存在使水体有机氮主要存在于颗粒相,有机氮的转化主要发生在水-颗粒物界面;③颗粒物的存在增加了微生物与有机氮的接触几率,促进了有机氮的转化.     

亚氯酸盐控制滤池亚硝化现象研究

对滤池亚硝化现象进行研究,综合分析了常规滤池在饮用水处理过程中亚硝酸盐的积累现象及其诸多影响因素.在提出通常解决方法的基础上,着重探讨了采用亚氯酸盐控制滤池亚硝化现象的工艺.结果表明,亚氯酸盐对亚硝化细菌具有明显的灭活效果,投加0.2　mg/L的亚氯酸盐即可以较好地抑制滤池亚硝化现象.     

好氧颗粒污泥亚硝化工艺的启动与运行特性研究

以具有硝化功能的活性污泥与厌氧产甲烷颗粒污泥的混合物接种小试曝气上流式污泥床反应器,采用自配无机氨氮废水为进水,在中温（30～35℃）条件下成功培养获得亚硝化颗粒污泥,亚硝化工艺的进水NH^＋₄-Ｎ负荷可达2 .5～3 .0 kg/(m^３·d),氨氮去除率和亚硝化率均可稳定在90%以上;进水中约100 mg/Ｌ的有机COD对亚硝化工艺的运行无明显影响;常温（约20℃）条件下亚硝化工艺也能高效稳定运行.     

三相流化床中人苍白杆菌与硝化菌对苯胺废水的共基质降解

将人苍白杆菌(Ochrobactrum anthropi)降解苯胺的过程与硝化反应相结合,在三重环流三相流化床中实现共基质降解,充分降低废水中的苯胺和苯胺降解过程中产生的NH4 -N.以自行研制的聚氨酯填料为载体,研究了流化床内苯胺、DO以及NaHCO3等对该共基质降解过程的影响.挂膜过程中苯胺质量浓度下降和NH4 质量浓度上升,证明了此过程中人苍白杆菌生物膜优先形成,而且NH4 质量浓度先增后降反映了人苍白杆菌生物膜的形成为硝化菌生物膜的形成创造了条件.通过苯胺对硝化菌的抑制性实验发现,苯胺质量浓度从100 mg/L下降到4 mg/L的过程中,其对硝化菌的抑制作用由强变弱.当苯胺质量浓度小于4 mg/L时,对硝化菌无抑制作用.其中亚硝化细菌比硝化细菌活性恢复更快,表明硝化菌比亚硝化菌对苯胺的毒性抑制更为敏感.流化床高效的传氧能力可以改善硝化细菌摄O2的条件.DO 2～3 mg/L,pH=7.5～8.5及适当的NaHCO3添加量是苯胺与NH4 -N共基质降解的适合条件.此条件下进水COD和苯胺质量浓度分别为540 mg/L及210 mg/L左右时,出水能够达到国家一级排放标准.