细微泥沙粒径对活性污泥产率的影响及其计算公式

针对我国城镇污水处理厂进水SS/BOD5值普遍偏高,在取消初沉池后出现泥沙淤积、污泥浓度提高和污泥MLVSS/MLSS(f)值下降等问题,利用实验室SBR研究了不同粒径的细微泥沙对活性污泥产率的影响,并在对国内外现有污泥产率公式进行具体分析的基础上,提出了对于污泥产率公式的优化方法,并借此推导出f值的预测表达式。结果表明:当在进水中分别掺入体积平均粒径为19.8、72和118.6 μm的细微泥沙300 mg/L时,在系统运行36 d后,污泥浓度从启动初期的3 450分别提高至7 898、5 389和3 742 mg/L,MLVSS/MLSS则从0.67分别下降为0.33、0.48和0.59;活性污泥产率由0.498分别提升至1.257、0.813和0.575 kg MLSS/kg BOD5,利用悬浮系数ω对ATV污泥产率公式进行优化修正,计算值与实测值的相对误差分别由修正前的46.1%、125.8%和219.3%降至修正后的8.4%、8.9%和3.5%,所得的产率更贴近实际;通过修正后的ATV产率公式建立f值的预测表达式,计算值与实测值的相对误差分别为18.3%、12.6%和4.4%。     

不锈钢尾渣重金属回收工业实验与应用

为降低堆存不锈钢尾渣重金属浸出危害和生产钢渣肥料,进行了重金属湿法回收工业实验。实验结果表明,金属品位和综合回收率可达到86%、95%;Cr、Ni平均回收率可达到90%。将研究成果运用到山西太钢不锈钢尾渣处理工程实践上,取得了良好的效果。通过对工艺流程和调试过程的介绍,从重金属矿物相组成和分选机理入手,分析了工艺特点和影响因素,为工艺推广应用提供了参考。     

沼气增温与控制系统的设计与仿真

冬季北方寒冷地区温度偏低,难以满足大中型沼气厌氧发酵系统对于温度的要求。为了解决该问题,针对天津地区某奶牛场沼气工程,设计了一套回收发电机余热并辅助电加热为发酵罐体供热的沼气增温控制系统,且实验确定最佳控制温度为35℃。在该系统中,罐体内部均匀布置竖直型循环加热管路,从而使料液温度分布更加均匀,热响应更加迅速,6 d左右即可将发酵罐内发酵料液提升到所需最佳温度;另外,采用罐内部温度及循环水流量的反馈调节,使料液的温度波动维持在±1℃范围内,解决了在冬季由于温度过低而导致沼气产气率偏低、甚至停滞的问题;同时,采用MATLAB软件对基于F-PID及传统PID的温度控制系统进行了仿真。对比结果表明,F-PID控制器较传统PID控制器超调量减小3℃,响应时间缩短60%,表明F-PID系统具有更高的效率、稳定性及实用价值。     

入口速度对静电monolith过滤器通道过滤性能的影响

采用单通道理论模型分析了表面带有静电的monolith过滤器通道的过滤性能。重点研究了气流入口速度大小和方向对通道捕获效率的影响,为设计和制造高效率低能耗的monolith过滤器提供理论指导。结果表明:对于直径1 μm以下粒子气流入口速度大小u0的增加会降低通道的捕获效率,当u0>3 m/s时,通道的捕获效率接近于零,对于直径1 μm以上粒子随着气流入口速度u0的增加,通道的捕获效率先减小后增大,出现一个极小值;在保证过滤器流量下,气流入口角度的增大会增加通道对直径1 μm以上粒子的捕获效率,而对直径1 μm以下粒子的捕获效率几乎没有影响。     

冻融-碳化耦合环境下自燃煤矸石混凝土耐久性实验研究

为研究冻融-碳化耦合环境下自燃煤矸石混凝土耐久性能,通过冻融-碳化与碳化-冻融2种耦合环境实验,分析其质量、动弹性模量、抗压强度及碳化深度等损失特性,揭示冻融-碳化耦合环境作用机理。结果表明:冻融-碳化环境下质量、相对动弹性模量损失率均与循环次数、水灰比呈正相关;小于63次,碳化-冻融环境劣化其质量能力强于冻融-碳化环境;超过63次,冻融-碳化环境劣化能力强于碳化-冻融环境;冻融-碳化环境劣化动弹性模量能力高于碳化-冻融环境。初期碳化反应在一定程度上能促进强度增长,但冻融100次且碳化14 d后,冻融-碳化环境下强度损失率与水灰比呈正相关。冻融-碳化环境下碳化深度与时间、水灰比呈正相关,冻融环境是加速其碳化腐蚀的催化剂,碳化-冻融环境劣化碳化深度强于冻融-碳化环境,2种耦合环境碳化差值0.87~2.10 mm。为深入研究煤矸石混凝土在复杂环境中的耐久性提供参考。     

城市污泥产品林地施用效果与风险评价

为探究城市污泥产品的林地施用效果,以北京排水集团生产的城市污泥产品(有机营养土、生物碳土、复合生物碳土)为研究对象,在北京市大兴区建立了城市污泥产品林地施用示范区.通过现场施用,研究3种城市污泥产品在不同施肥方式、不同施肥量下对林地环境及毛白杨生长的影响.结果表明,土壤的酸碱度与施肥前相比有小幅度的上升,最终稳定在7....     

连续施用城市污泥后林地土壤中重金属的含量变化及生态风险

将堆肥污泥施用于林地能够增加土壤肥力,促进林木增长,具有广阔的应用前景,但污泥中所含重金属进入土壤环境后的积累特征及所引起的生态风险问题亦备受关注.连续5年将污泥堆肥产品施用于林地并对相应林地土壤重金属含量进行了同步监测,采用单因子指数法和潜在生态危害指数法分析评价了污泥堆肥泥质、污泥堆肥不同施用比例以及是否连续施肥等...     

Biodegradation Behaviors of Poly(p-dioxanone) in Different Environment Media

This work was aimed at researching the aerobic biodegradation of poly(p-dioxanone) (PPDO), a novel kind of degradable polymer material, by simulating real-life conditions in a laboratory-scale test, specified by the standard methods based on two biodegradation environments, composting and aqueous media. To measure and describe the biodegradability of PPDO, not only had carbon dioxide produced by respiratory metabolism of microorganism been measured, which determines the ultimate aerobic biodegradability of chemical compounds, but also the detailed results of biodegradation were further characterized by monitoring physical, chemical and thermal properties changes of test materials at different incubation times in the two media, confirmed by using the appropriate analytical techniques. Scanning electron microscopy was used to observe the surface morphology, and the thermal performance of PPDO was characterized by differential scanning calorimetry. The changes of molecular weight were detected by intrinsic viscosity ([η]) and gel permeation chromatography, and the variations of the molecular structure were monitored by the nuclear magnetic resonance and FT-IR. The results show that PPDO has outstanding character of biodegradation and may be more adapted for biodegrading in liquid medium than in composting.     

Application of response surface methodology to the treatment landfill leachate in a three-dimensional electrochemical reactor

The influence of different variables on the removal of ammonia nitrogen and COD from landfill leachate was investigated in a three-dimensional electrochemical reactor. Box–Behnken statistical experiment design and the response surface methodology were used to investigate operating condition effects, such as current density, activated carbon to water ratio and the reaction time, on ammonia nitrogen removal efficiency and COD removal efficiency. The positive and negative effects of variables and the interaction between variables on ammonia nitrogen removal and COD removal were determined. The response surface methodology models were derived based on the results and the response surface plots were developed accordingly.