初始温度对人粪便好氧堆肥过程的影响

温度是好氧堆肥过程中需要控制的一个重要因素。不同的初始温度直接影响了堆肥过程中微生物活性及有机物的降解。为了研究初始温度对粪便好氧堆肥过程的影响,采用序批式好氧堆肥反应器,以新鲜锯末为载体,控制含水率在55%~60%的范围左右并强制通风的好氧条件下,进行了初始温度分别为25、35、45和55℃,20 d为一个周期好氧堆肥实验,研究了不同初始温度条件下堆肥过程有机物降解、氮的迁移转化及种子发芽指数的变化。结果表明,初始的高温度会抑制堆肥反应的进行,但初始温度越高,水解效果越显著;初始的高温有利于COD的去除,最终COD的去除率分别为88.2%、89.3%、92.0%和89.9%。初始高温对种子发芽率有抑制作用,同时延迟了堆肥的腐熟期。     

高温滤袋的有效清灰强度

对Φ120 mm×1 000 mm氟美斯滤袋的最大侧壁压力峰值、除尘器运行阻力进行实验测试,并结合滤袋破损情况探究高温滤袋的有效清灰强度。结果表明,最大侧壁压力峰值在一定范围内对滤袋有较好的清灰效果且对滤袋的损伤较小。对粉煤灰而言,滤袋沿长度方向的平均最大侧壁压力峰值为876 Pa时的强度能满足除尘器的清灰要求,随着滤袋的最大侧壁压力峰值增大,除尘器清灰效果越好,当平均最大侧壁压力峰值超过2 713 Pa时,清灰效果仅轻微提升;且局部最大侧壁压力峰值大于5 282 Pa时滤袋破损,造成过度清灰。     

基于DO控制实现SBR短程硝化过程

采用序批式反应器(SBR)处理模拟氨氮废水,研究了固定供氧模式下氨氮降解过程和溶解氧变化规律,并对DO控制实现短程硝化机理进行了探讨.实验结果表明,当DO＜1 mg/L时,体系产生亚硝酸盐积累,当亚硝化反应结束后,DO出现跃升现象,并且pH值对短程硝化有一定影响,充足的碱度和较高的pH值有利于建立以DO为控制参数实现短程硝化过程控制.短程硝化启动后,亚硝酸盐积累率达90％以上,并且经过度曝气5d后,系统仍保持稳定运行.     

SMBBR预处理发酵类制药废水

采用高活性反硝化菌DNF409作为菌种,以SDC-03型生物载体作为填料,通过特异性移动床生物膜反应器预处理发酵类制药废水。实验结果表明:在反应温度为22~26℃、DO为2~4 mg/L、污泥质量浓度为2 000 mg/L、水力停留时间为16 h的条件下,COD,NH3-N,TN,TP的平均去除率分别为72.45%,27.72%,18.54%,84.58%,BOD5/COD由0.17提高到0.38,废水的可生化性得到提高;出水经后续生化处理达到GB 21903—2008《发酵类制药工业水污染物排放标准》的排放要求。     

复合混凝剂的制备及活性染料的去除

以马铃薯淀粉、丙烯酰胺（AM）和二甲基二烯丙基氯化铵（DADMAC）为原料进行接枝反应,将接枝产物（TSI）与聚合氯化铝铁（PAFC）复配,制得新型复合混凝剂PAFC-TS1。优化了复合混凝剂制备的工艺条件。研究结果表明,复合混凝剂PAFC-TS1的优选制备条件为：OH^-浓度与铝铁总浓度的比（r）为0.5,铝铁总浓度与TS1的质量浓度比（R_m）为0.5 mol/g,铝铁摩尔比9∶1。在此条件下处理质量浓度为100 mg/L的活性染料废水,当混凝剂投加量为24 mL/L时,染料去除率可达97%以上。相同条件下,使用PAFC-TS1比单独使用PAFC或PAFC-PAM的染料去除率更高。     

Effect of flue gas recirculation on nitric oxide (NO) emissions during the coal grate-fired process

Flue gas recirculation (FGR) is a low nitrogen oxide (NO_X) combustion technology. The present study used standard gas to simulate the cycle gas (the main ingredients of which are oxygen (O₂), nitrogen (N₂), and carbon dioxide (CO₂)). The coal grate-fired process was divided into three zones, namely (1) volatilization zone, (2) main combustion zone, and (3) char combustion and burn-out zone. The effects of FGR on coal combustion and NO emissions were investigated in these zones of a unit-boiler experimental system. An industrial test was then conducted on a chain boiler that previously used FGR. Data showed that if the cycle gas was directed into the furnace from the volatilization zone, the curve of the coal surface temperature moved backwards, the temperature peak increased, and coal ignition was delayed. When the FGR rate was 20%, NO emissions/g coal was 41.8% less than in the absence of FGR, in the overall combustion process except for the volatilization zone. An industrial test demonstrated that FGR decreased the NO emissions and incomplete-combustion loss of gas. NO and carbon monoxide (CO) emissions were reduced by 26.9 and 38%, respectively. These observations may prove to be beneficial in reducing ambient air pollution and saving energy.     

太湖西北部湖区入湖河流氮磷水质标准修正方案研究

氮磷污染一直是太湖流域的首要污染问题,有效遏制氮磷入湖量的增加是治理太湖的重要任务。然而由于我国现行的地表水环境质量标准(GB3838-2002)中河流和湖泊氮、磷水质标准存在差异,即河流无总氮控制指标、河湖总磷标准不一致的问题,往往造成通过控制入湖河流污染来改善太湖湖泊水质时,湖泊污染物浓度往往达不到治理目标。以太湖西北部湖区及其入湖河流为例,利用BATHTUB模型模拟入湖河流与湖泊TN、TP的关系,推算太湖在满足现行湖泊水质标准中TN和TP各类别目标值的情形下的环境容量并以此环境容量决定入湖河流的水质,进而提出相应的方案进行比选,从而提出太湖入湖河流氮磷水质标准修正方案。结果表明:(1)当太湖入湖河流执行现行河流水质TP标准时,对应湖泊的水质TP超标,并不能达到保护湖泊的目标;(2)当太湖西北部湖区入湖河流TN、TP执行现行湖泊水质标准,对应湖区水质均能达标并且优于目标限值,然而该方案对于污染较为严重的太湖区域的实际参考意义不足;(3)以现行湖泊水质标准TN、TP各类别为目标值反推计算入湖河流水质指标,既能保证湖泊水质达标,又不会使河流水质标准过于严格,因此其结果可作为入湖河流水质标准修正的参考,从而提出太湖入湖河流TN、TP水质标准建议方案。     

Diffusion of municipal wastewater treatment technologies in China: a collaboration network perspective

The diffusion of municipal wastewater treatment technology is vital for urban environment in developing countries. China has built more than 3000 municipal wastewater treatment plants in the past three decades, which is a good chance to understand how technologies diffused in reality.We used a data-driven approach to explore the relationship between the diffusion of wastewater treatment technologies and collaborations between organizations. A database of 3136 municipal wastewater treatment plants and 4634 collaborating organizations was built and transformed into networks for analysis. We have found that: 1) the diffusion networks are assortative, and the patterns of diffusion vary across technologies; while the collaboration networks are fragmented, and have an assortativity around zero since the 2000s. 2) Important projects in technology diffusion usually involve central organizations in collaboration networks, but organizations become more central in collaboration by doing circumstantial projects in diffusion. 3) The importance of projects in diffusion can be predicted with a Random Forest model at a good accuracy and precision level. Our findings provide a quantitative understanding of the technology diffusion processes, which could be used for waterrelevant policy-making and business decisions.

Open image in new window

     

河北平原农田土壤重金属形态分布特征及控制因素研究

土壤重金属污染防治已迫在眉睫,国内外对重金属污染研究热度不减。本文选择河北平原农田为研究区,对采集325个根系土样品中的Cd、Cr、Pb、As、Hg等5种重金属进行了各形态含量统计与分析,并用Arc GIS制作了有效态空间分布图。最后运用相关性分析法探讨了5种重金属各形态与全量及pH值、Fe_2O_3、总有机碳(TOC)、阳离子交换容量(CEC)、粘粒的相关性。研究表明:Cd的有效态(水溶态和离子交换态)含量占全量比重最大,为18.06%,Cr、Pb、As、Hg均低于10%,这4种金属以残渣态为主,占全量的50%以上;As元素各形态与全量、pH值、Fe_2O_3、TOC、CEC、粘粒的相关程度最高,成正相关关系;Cr的3种形态(铁锰氧化态、强有机结合态、残渣态)与Fe_2O_3、TOC、CEC、粘粒呈显著正相关关系,Cr碳酸盐结合态、腐殖酸结合态与pH呈正相关关系,与Fe_2O_3、TOC、CEC、粘粒呈显著负相关关系;5种重金属铁锰氧化态与pH均呈正相关关系。