Nitrogen and phosphorus removal for swine wastewater by ammonium crystallization and intermittent aeration process

Abstract

A process on crystallized precipitation of ammonium by adding magnesium salt and phosphate was carried out to improve C/N ratio in swine wastewater. After completion of crystallized precipitation of ammonium, an intermittent aeration process with aeration and non‐aeration periods alternated at interval of 1:1 hr day^‐1 is used for the improved swine wastewater (T‐N/BOD=0.14: BOD=8200 mg/liter and T‐N=1166 mg/liter). The results obtained from the experiment show that the removal ratios of T‐N and NH₄‐N are 91% and 99%, respectively. T‐P is not removed, while the removal ratio of PO₄‐P is 60% as 3% of CaCl₂ liquid is added. The results also indicate that dilution with water is effective to improve the removal of phosphorus even if raw swine wastewater contains high concentrations of T‐N, T‐P, BOD, and TOC.     

Changes in biomass activity and characteristics of activated sludge exposed to low ozone dose

In this paper, the response mechanism of activated sludge exposed to low-dose ozone at less than 20 mg O₃ g⁻¹ total suspended solids (TSS) was studied by analyzing the changes in sludge activity and the evolution of C, N, P and metals from sludge following ozonation. The intracellular ATP concentration was not affected at less than 5 mg O₃ g⁻¹ TSS and thereafter decreased rapidly to around 60% when the ozone dose increased to 20 mg O₃ g⁻¹ TSS. Similarly, the efficiency of sludge solubilization initially changed a little and then increased rapidly to around 30% at an ozone dose of 20 mg O₃ g⁻¹ TSS. However, the activities of superoxide dismutase and protease decreased immediately upon exposure to ozone. These findings indicate that ozone firstly destroys the floc, leading to the disruption of the compact aggregates, which does not affect cells viability but induces a decrease in enzyme activities. Ozone then attacks the bacterial cells of the sludge, causing a decrease in cells viability. During ozonation, the content of carbon, nitrogen and phosphorus in the sludge matrix decreased, while the content of these elements in the micro-solids and supernatant gradually increased. Most of the released metals from the sludge matrix were found in the micro-solids.     

功能可控型减隔震支座的研发与性能分析∗

为提升梁式桥的抗震性能,实现桥梁结构在地震作用下力学行为的可控性,基于减隔震设计原理,研发了一种功能可控型减隔震支座。通过数值模拟和模型试验研究了该支座的力学行为,结果表明:支座的滑动性能良好,摩擦行为稳定;剪力销力学行为可控,断后摩擦行为正常;环形钢阻尼元件滞回曲线饱满,耗能能力强;可控型支座整体力学行为稳定可控。最后以某3跨桥梁为例分析了可控型支座的减隔震效果,结果表明:合理选用可控型支座可以实现结构在地震作用下力学行为的可控性,使结构响应在力和位移之间取得较好的平衡,从而达到避免桥墩损伤破坏、防止落梁的目的。     

Development and case study of a science-based software platform to support policy making on air quality

This article describes the development and implementations of a novel software platform that supports real-time, science-based policy making on air quality through a user-friendly interface. The software, RSM-VAT, uses a response surface modeling (RSM) methodology and serves as a visualization and analysis tool (VAT) for three-dimensional air quality data obtained by atmospheric models. The software features a number of powerful and intuitive data visualization functions for illustrating the complex nonlinear relationship between emission reductions and air quality benefits. The case study of contiguous U.S. demonstrates that the enhanced RSM-VAT is capable of reproducing the air quality model results with Normalized Mean Bias < 2% and assisting in air quality policy making in near real time.     

黑龙江省大气污染防治思路研究

近年来,全国各地出现不同程度的雾霾天气,大气污染严重,黑龙江省部分城市大气也出现不同程度污染,本文通过分析导致大气污染的三个主要成因,即:气候条件不利于污染物扩散;煤炭消耗处于主导地位;机动车迅速发展.提出黑龙江省未来十年的大气污染防治思路和地区产业发展方向的几点建议,通过采取综合、系统的措施,完善大气污染治理制度和政策保障体系、建立分区管理、加强污染基础研究、发展绿色经济等多方面入手,冀希能够改善本省的空气质量.     

Activated carbon enhanced ozonation of oxalate attributed to HO. oxidation in bulk solution and surface oxidation： Effect of activated carbon dosage and pH

Ozonation of oxalate in aqueous phase was performed with a commercial activated carbon（AC）in this work. The effect of AC dosage and solution pH on the contribution of hydroxyl radicals（HOU） in bulk solution and oxidation on the AC surface to the removal of oxalate was studied. We found that the removal of oxalate was reduced by tert-butyl alcohol（tBA） with low dosages of AC,while it was hardly affected by tBA when the AC dosage was greater than 0.3 g/L. tBA also inhibited ozone decomposition when the AC dosage was no more than 0.05 g/L, but it did not work when the AC dosage was no less than 0.1 g/L. These observations indicate that HOUin bulk solution and oxidation on the AC surface both contribute to the removal of oxalate. HOU oxidation in bulk solution is significant when the dosage of AC is low, whereas surface oxidation is dominant when the dosage of AC is high. The oxalate removal decreased with increasing pH of the solution with an AC dosage of 0.5 g/L. The degradation of oxalate occurs mainly through surface oxidation in acid and neutral solution, but through HOUoxidation in basic bulk solution. A mechanism involving both HOUoxidation in bulk solution and surface oxidation was proposed for AC enhanced ozonation of oxalate.     

基于能值分析的喀什可持续发展水平的研究

采用能值分析的方法,通过计算出能值产出率,环境负载率,可持续发展指数等指标,对喀什2002-2010年的可持续发展水平进行研究.研究结果表明,喀什的可持续发展水平ESI值从2002年的1.26增加到2010年的5.8.喀什的可持续发展水平总体在逐年增长,但也呈现一定的波动,其中由于旅游收入的增加2004年的ESI为0.68,为历年最低.2006年开始有所回升,2010年由于输入资源的减少,ESI值达到近几年最高5.8.通过分析可持续发展指数的变化,可以表明喀什的发展状况,为喀什实现可持续发展提供一定的参考依据.     

某城市污水处理厂污泥固化处理研究

课题依托哈尔滨某污水处理厂,通过建立L9(34)正交试验,选取水泥、石灰、煤灰掺入比例以及养护时间为主要影响因素,以固化块的抗压强度和COD浸出浓度为评价指标,得到各因素的影响度大小排序为:水泥养护天数石灰煤灰,优化固化条件为水泥掺入比例15%,石灰掺入比例2%,煤灰10%养护天数6 d。以此为基础进行延展实验,探讨以上因素对污泥固化效果的影响,获得最佳配方。     

重金属铅在线监测仪器性能对比研究

污染源在线监测仪器的准确性、实时性、连续性与污染源在线监测系统数据可靠性紧密相关。选取4个不同品牌的铅在线监测仪器,综合评价在线测定性能。结果表明,3种铅在线监测仪器的准确度小于10%,4种铅在线监测仪器的零点漂移、量程漂移、重复性误差均小于5%,定量下限小于0.05 mg/L,能较好地应用于铅的在线监测。     

掺杂过渡金属的TiO2/累托石复合材料的制备及其光催化性能研究

以累托石为载体,钛酸四丁酯和硝酸铜为原料,采用溶胶-凝胶法制备出了掺杂过渡金属铜的TiO2/累托石复合光催化材料,并对其进行了X射线衍射(XRD)和红外光谱(FT-IR)的表征.同时考察了复合材料在紫外光照下对对氯苯酚的光催化活性,研究了铜掺杂量和煅烧温度等因素对复合材料光催化活性的影响,探讨了过渡金属掺杂改性TiO2的机理及对氯苯酚的光催化降解机理.实验结果表明:在制备复合材料的过程中,累托石的层状结构遭到一定程度的破坏;复合材料中的TiO2主要是以大部分的锐钛矿型和小部分的金红石型的混合形态存在;负载累托石后复合材料的吸附性能明显增加,掺杂铜的TiO2/累托石复合材料的光催化活性要高于未掺杂铜的TiO2/累托石复合材料,并且当掺铜量为0.5%(质量分数),煅烧温度为500℃时,复合材料对对氯苯酚的光催化去除率达到最大;苯醌类物质可能是对氯苯酚光降解的中间产物.