混凝—膜分离集成技术处理吡喹酮废水

吡喹酮生产废含有大量有机胶体污染物和ＫＣＮ。混凝－膜分离集成技术，以聚 为混凝剂，聚丙烯酰胺为助凝剂对废水进行混凝预处理，去除胶体污染物质后，再用充气膜吸收技术回收废水中的ＫＣＮ。     

中空纤维膜吸收甲苯气体

采用疏水性聚偏氟乙烯(PDVF)中空纤维膜为气液接触膜,n-甲酰吗啉(NFM)水溶液为吸收剂,研究了膜吸收技术分离甲苯/空气混合气的性能。考察了进气气体浓度、气体停留时间、吸收液体积分数和吸收液流量等诸因素对分离性能的影响。研究结果表明,膜吸收技术可以有效地分离甲苯/空气混合气,甲苯去除率可达90%;提高NFM吸收液的浓度和流量可同时增加甲苯的去除效率η和总传质系数K;气体停留时间的减小导致η降低,K反而增大;进气甲苯浓度的增加导致η下降,同时降低总传质系数K。     

应用POMS复合膜分离去除废气中挥发性有机污染物

依靠POMS平板单层膜或POMS卷式膜上选择性分离层的选择性溶解和渗透作用,常温负压分离回收废气中乙酸乙酯等挥发性有机污染物(VOC)组分.结果表明,膜两侧操作压差和原料气流量对乙酸乙酯分离效率影响较大;当原料气处理量为1.770 0～2.810 0 m3/(m2·h)、膜两侧操作压差为0.08 MPa,POMS卷式膜乙酸乙酯渗透速率可达7.86 × 10-7 mol/(s·m2·Pa);乙酸乙酯为1 500～4 500 mg/m3时,其去除率可达80%.测得几种VOC组分在POMS复合膜中的溶解吸附量都比较可观,由此预测该膜处理废气中VOC可取得很好的净化效果.甲苯在POMS复合膜中的溶解吸附量低于乙酸乙酯,其实验测得渗透速率也小于乙酸乙酯.甲苯去除率也能达到80%.     

膜萃取技术回收浓缩废水中的邻甲苯胺

采用均质硅橡胶膜构建了卷绕式膜组件,以盐酸溶液为萃取液回收浓缩废水中的邻甲苯胺。通过考察进水浓度、萃取液p H、温度、离子强度、进水流速等因素对去除过程及回收率的影响,探讨了采用膜萃取技术回收浓缩邻甲苯胺的条件与机制。结果表明:膜萃取技术可以将2 g/L的邻甲苯胺废水浓缩至约10 g/L,且随着料液浓度增加,邻甲苯胺回收率先增后降,过高的邻甲苯胺浓度可能会造成膜选择性下降;萃取液p H是影响回收率的重要因素之一,1≤p H≤2时污染物回收率高于95%;无机盐离子可以促进邻甲苯胺的回收,当盐离子含量超过10%时,回收率显著提高;进水流速在2~20m L/min之间变化时,回收率先增后降,膜阻和解吸速率依次成为主要影响因素。该实验研究表明,膜萃取技术可以高效节能地的浓缩回收生产废水中的邻甲苯胺。     

膜气体吸收技术分离VOCs/N2混合气性能的研究

以C₆H₆/N₂混合气为代表,疏水性聚丙烯中空纤维膜为气液接触膜,n-甲酰吗啉(NFM,n-formyl morpholine)水溶液为吸收剂,研究了膜气体吸收法分离VOCs/N₂混合气性能。考察了吸收剂流量、吸收剂体积分数、进口气流量、进口气浓度和膜组件结构等诸因素对分离性能的影响。结果表明,在吸收剂流量为20～100 mL/min,进口气流量为40～300 mL/min,进口气浓度为10.2 mg/L的条件下,苯的去除率为65.0 % ～ 99.6 %,总体积传质系数为0.0157～0.08412 s^-1。实验证明,采用疏水性多孔膜气体吸收法,NFM水溶液吸收分离VOCs/N₂混合气具有较高的分离效率和较快的传质速率。     

膜基活化溶液中活化剂在回收温室气体CO2过程中的作用

将AMP和PZ作为活化剂添加于MDEA溶液中,形成活化溶液,研究了膜基活化溶液回收温室气体CO₂性能,着重考察活化剂的活化作用和对膜接触器传质加强的影响,提出一个活化机理来解释活化现象,建立了阻力层方程模型, 并模拟膜基活化溶液回收CO₂的传质过程。结果表明,活化剂对膜接触器传质的加强起到重要作用,具有双氨基环状结构的PZ对传质的加强作用高于具有空间位阻结构的AMP;活化溶液的CO2回收率和传质通量明显高于未活化的MDEA溶液,活化性能PZ＞AMP;活化剂的活化效应与分子结构有关;流体力学的改变对传质的影响有限,活化剂的反应动力学对传质的加强起主导作用;阻力层方程模型能较好地模拟膜基活化溶液回收CO₂传质过程,传质通量和总传质系数的模型值与实验值符合较好。     

膜基活化溶液中活化剂在回收温室气体CO2过程中的作用

将AMP和PZ作为活化剂添加于MDEA溶液中,形成活化溶液,研究了膜基活化溶液回收温室气体CO2性能,着重考察活化剂的活化作用和对膜接触器传质加强的影响,提出一个活化机理来解释活化现象,建立了阻力层方程模型,并模拟膜基活化溶液回收CO2的传质过程。结果表明,活化剂对膜接触器传质的加强起到重要作用,具有双氨基环状结构的PZ对传质的加强作用高于具有空间位阻结构的AMP;活化溶液的CO2回收率和传质通量明显高于未活化的MDEA溶液,活化性能PZ〉AMP;活化剂的活化效应与分子结构有关;流体力学的改变对传质的影响有限,活化剂的反应动力学对传质的加强起主导作用;阻力层方程模型能较好地模拟膜基活化溶液回收CO2传质过程,传质通量和总传质系数的模型值与实验值符合较好。     

膜吸收法处理高氨氮废水的研究

对影响膜吸收过程的几个因素进行了正交实验和其他相关实验 ,结果表明 ,在一般情况下 ,废水中的pH为显著影响因素 ,而温度、废水流速和废水中氨氮浓度都不是显著影响因素 ;吸收液 (H2 SO4 )浓度在 0 .5mol/L以上时 ,传质系数K值变化很小。     

乳化液膜法对废水中酚的高效去除与富集

采用绿色高效的乳化液膜法(GELM)去除与富集废水中的酚类污染物,建立了以棕榈油和煤油混合物(7:3)为膜溶剂、聚异丁烯多丁二酰亚胺(T-155)为表面活性剂、正辛醇为载体的乳化液膜体系,提高了GELM法分离酚的能力,并研究了各因素对液膜稳定性及对废水中苯酚的分离富集效果的影响。乳化液稳定性和分离酚的实验结果表明,在最优条件下,乳液稳定性好,且该乳化液膜对废水中苯酚和COD去除率分别为99.5%和74%,对邻甲酚、邻氯苯酚、邻氨基苯酚等酚类污染物的除酚率均达～99%,在初始酚浓度4 000 mg·L^-1时,除酚率仍然达～90%,说明该体系可实现对酚的高效去除。此外乳化液膜对苯酚的富集倍数随乳外比的增大而增大,在乳外比为1∶10时苯酚富集约16倍,说明该体系实现了对苯酚的有效富集。研究结果可为废水中酚类污染物的去除与资源化回收提供绿色、高效、低成本解决方法。     

膜气体吸收技术分离VOCs/N2混合气性能的研究

以C6H6/N2混合气为代表,疏水性聚丙烯中空纤维膜为气液接触膜,n-甲酰吗啉(NFM,n-formyl morpholine)水溶液为吸收剂,研究了膜气体吸收法分离 VOCs/N2 混合气性能.考察了吸收剂流量、吸收剂体积分数、进口气流量、进口气浓度和膜组件结构等诸因素对分离性能的影响.结果表明,在吸收剂流量为 20～100 mL/min,进口气流量为 40～300 mL/min,进口气浓度为 10.2 ms/L的条件下,苯的去除率为 65.0%～99.6%,总体积传质系数为 0.0157～0.08412 s-1.实验证明,采用疏水性多孔膜气体吸收法,NFM 水溶液吸收分离 VOCs/N2 混合气具有较高的分离效率和较快的传质速率.     

Analysis of volatile fatty acids in wastewater collected from a pig farm by a solid phase microextraction method

The main purpose of this study is to develop a reliable Solid Phase Microextraction (SPME) method for monitoring the concentration of volatile fatty acid (VFA) in the wastewater collected from pig farms. Ten volatile fatty acid species were spiked in 2 ml of swine wastewater and extracted with a carbowax coated extraction fiber to evaluate the accuracy and precision of the method. The fiber was introduced into a gas chromatography system by thermal desorption and detected by a mass spectrometer detector. The estimated method detection limits ranged from 11.5 mM/L for formic acid to 0.03 mM/L for heptanoic acid. The method is more sensitive than the sample direct injection method. The percentage recovery of analytes ranged from 77.3 for propanoic acid to 114.1 for formic acid at the spike level of 19.09 mM/L. The compound absorption rate varied significantly with the fiber absorption time for n-Valeric, isocaproic, n-caproic and heptanoic acids. An SPME method with twenty minutes fiber absorption and three minutes thermal desorption was tested in this study and resulted in good reproducibility for analyzing VFAs in swine wastewater. The method may be applied for scanning a wide spectrum of polar organic compounds in environmental samples.     

Effect of bubble-induced surface turbulence on gas-liquid mass transfer in diffused aeration systems.

Models that predict volatilization of organic compounds from wastewater treatment basins may underestimate emission rates if the surfaces are considered as quiescent. In reality, the water surface may be agitated by subsurface aeration, increasing mass transfer across the tank surface air-water interface. This study investigated the effect of turbulence, induced by diffused bubble aeration, on mass transfer at the water surface of a pilot aeration basin. The mass transfer of ammonia from an enclosed headspace over the basin to acidified water was measured when different diffuser types and airflow rates were applied. Oxygen-transfer tests were conducted immediately following each ammonia-transfer test. Increasing airflow rates through fine- and coarse-bubble diffusers had a significant effect on the ammonia mass-transfer rate. Experimental mass-transfer parameters (K(L)a's) for surface volatilization derived with aeration present were up to 48% higher than the K(L)a values for quiescent conditions over the range of conditions tested. No effect of diffuser type on ammonia transfer could be determined. The study results infer an effect on oxygen transfer into the water at the surface and potential transfer of volatile organic compounds, if present, from the water. The results of the ammonia mass-transfer experiments suggest that adjustments to the existing mass transfer correlations for surface volatilization from aeration basins may be in order. Such adjustments will have the greatest effect on predictions for the less volatile compounds, under conditions of low airflow rates.     

用于废水处理的膜曝气生物反应器

膜曝气生物反应器是一种利用透气膜进行曝气的污水生物处理组合新工艺.膜曝气的主要特点在于无泡曝气和特殊结构的生物膜.无泡曝气可提高传氧效率,在高浓度废水或含挥发性有机物废水的处理中具有优势.曝气膜上生长的生物膜具有传质异向性,这一特点使其具有同步除碳脱氮的潜力.介绍了膜曝气生物反应器的工艺特点,总结了国内外对于膜曝气生物反应器在废水处理方面的研究进展,指出当前膜曝气生物反应器应用中存在的问题,并展望了今后的发展前景.     

对羟基苯甘氨酸生产废水的处理工艺研究

对羟基苯甘氨酸废水属于高浓度难处理有机废水,针对生产工艺的特点,采取了废水分类处理的新路线.试验结果表明,高浓度废水经过物化处理后,苯酚的回收率达到95%,每日回收硫酸铵约6t;低浓度废水采取水解酸化-接触氧化-沉淀-活性炭吸附工艺是可行的,COD、BOD5、NH3-N及挥发酚的总去除率分别为95.6%、94.6%、93.7%和99%.     

抗生素废水的GC-MS分析与显色物质的初步确定

为确定抗生素废水中有机污染物构成和显色物质,以二氯甲烷为萃取剂,萃取废水中的有机物,经过浓缩纯化后,利用气相色谱质谱联用(GC-MS)技术对制药废水中的有机成分进行了分析鉴定,结合计算机质谱图库,定性确定了废水中60种有机污染物。其中,脂类为主要污染物成分,经对脱色后的废水进一步GC-MS分析后,初步确定油酸甲酯为此类抗生素废水的主要显色有机物。     

Applicability of Fenton and H2O2/UV reactions in the treatment of tannery wastewaters

In this paper we evaluated the H2O2/UV and the Fenton's oxidation processes for the treatment of tannery wastewater under different experimental conditions. Efficiencies were judged by the amounts of organic substances degraded or eliminated under these treatment techniques. Daphnia magna and Vibrio fischeri were used to monitor toxicity. Organic compounds contained in the untreated and treated tannery wastewater were determined and identified using substance specific techniques. Gas chromatography-mass spectrometry (GC-MS) in positive electron impact (EI(+)) mode was applied to determine volatile organics. Atmospheric pressure ionization (API) mass (MS) and tandem mass spectrometry (MS-MS) coupled with flow injection analysis (FIA) or liquid chromatography (LC) were used to detect or identify polar organic pollutants. The experimental results indicated that both oxidation processes--H2O2/UV at pH 3 and Fenton at pH 3.5--are able to reduce TOC content by mineralisation of the organic compounds.     

芦苇湿地对造纸废水中有机污染物的去除效果及机理

为了对芦苇湿地对造纸废水中有机污染物的去除效果及降解机理进行研究,本文采用GC-MS联用仪对经芦苇湿地处理前后造纸废水中有机污染物的组成和含量进行测定,并通过叠放色谱图的方法对造纸废水中有机污染物的降解效果进行分析。结果表明:(1)经芦苇湿地处理前造纸废水中共测出30种有机污染物,其中8种被列入美国EPA环境优先控制污染物黑名单。(2)纸浆造纸废水生物塘-芦苇湿地复合处理系统对有毒有机污染物基本上达到了较好的去除效果:有机污染物总量减少80%以上,且降解后的产物多为毒性较小的烷烃类。(3)利用质谱手段对有机污染物的降解规律进行了初步研究。该研究为造纸废水处理和资源化利用提供了科学依据,为"造纸废水-芦苇-造纸"生态纸业循环经济模式的进一步推广应用奠定了基础。     

造粒流化床颗粒污泥对溶解性有机物的吸附机理研究

造粒流化床对污染物的去除是由混凝沉淀和物理吸附协同作用完成的,然而对于溶解性污染物,混凝沉淀的效果不明显,根据作者的实验分析,物理吸附在溶解性污染的去除中发挥了重要的作用。作者利用静态实验的方法对流化床颗粒对葡萄糖的吸附和扩散传质过程进行了分析,并采用Langmuir方程、Freudlich方程和Weber-Morris颗粒扩散模型对实验数据进行了拟合。结果表明,颗粒对葡萄糖的吸附等温过程与Langmuir方程有很好的吻合性;颗粒对葡萄糖的吸附速度与颗粒内部的扩散过程有很好的相关性。     

Bacteria additives to the changes in gaseous mass transfer from stored swine manure

Abstract

A bacteria additives treatment experiment in assessing the changes in gaseous mass transfer from stored swine manure is presented. The experiment is tested for ammonia, methane, hydrogen sulfide, and carbon dioxide emission data sampled from pilot swine manure columns and analyzed by GC/MS. The result shows that bacteria additives slightly reduce the methane and carbon dioxide releases, while the same additives do not show any effect on the reduction of ammonia. The hydrogen sulfide contents of stored swine manure continued to be low. Gas concentrations emitted from treated and untreated stored swine manure were: 3.76 and 2.2 ppm for methane, 0.35 and 0.11 ppm for ammonia, and 1000 and 470 ppm for carbon dioxide, respectively. A simple model to estimate gas emission rates is also developed from the viewpoint of two‐film resistance theory. The average emission rates calculated from the model for methane, ammonia, and carbon dioxide are respectively: 0.01, 0.0005, and 13.98 g/min from untreated stored manure; while 0.07, 0.096, and 0.55 g/min from treated manure. The emission model also indicates that for most gaseous pollutants of environmental concern, liquid phase transfer coefficient controls the rate of volatile compounds emitted from stored swine manure and gas phase transfer coefficient has insignificant effect in the calculation of overall mass transfer coefficient.