一体式膜生物反应器处理生活污水的试验研究

对一体式膜生物反应器处理生活污水时污泥活性变化情况和对污染物去除效果进行了初步研究,试验结果表明:该工艺处理生活污水时应采取一定的排泥措施;系统内生物种类和数量相当丰富;影响CODCr去除率的主要原因在于污泥活性,而影响NH3-N去除率的主要原因在于溶解氧浓度.     

—体式膜生物反应器处理生活污水的试验研究

对一体式膜生物反应器处理生活污水时污泥活性变化情况和对污染物去除效果进行了初步研究，试验结果表明：该工艺处理生活污水时应采取一定的排泥措施；系统内生物种类和数量相当丰富；影响CODcr去除率的主要原因在于污泥活性，而影响NH3-N去除率的主要原因在于溶解氧浓度。     

膜生物反应器中铁含量对活性污泥性能的影响

通过分析膜生物反应器中铁含量对活性污泥性能的影响,得知在一定条件下,随着污泥中铁含量的升高,污泥的脱氢酶活性随之上升,上清液含铁量对污泥脱氢酶活性的影响跟污泥中含铁量影响相反;污泥含铁量对污泥比耗氧速率的影响与对脱氢酶活性的影响相反,其原因在于污泥浓度增加及污泥絮体变大影响了溶解氧和基质从反应器混合液向絮体内部的扩散,导致污泥内部氧气不足,从而使微生物的耗氧活性随之降低;随着上清液中铁含量的增加,污泥比耗氧速率随之升高,上清液中铁离子浓度的增高会使生物铁污泥性能劣化,导致生物铁污泥絮体的解絮,污泥颗粒变小,污泥内部溶解氧上升,从而使污泥耗氧活性增高,因此合理投加一定量的生物铁才能使污泥性能达到最佳。     

一体式膜生物反应器作为反渗透预处理技术的试验研究

为给某企业的反渗透系统提供稳定的优质进水,采用一体式膜生物反应器对某城市污水处理厂二级出水进行了深度处理中试试验。研究结果表明:在进水COD的质量浓度为7～15 mg/L时,色度为20～50度,浊度为0.70～3.57 NTU,膜通量10.0～13.75 L/(m2.h)、跨膜压差0.019～0.038 MPa、曝气量20 m3/h、制水时间40min、停机时间3 min、HRT 3.6～5.0 h条件下,MBR系统出水COD质量浓度小于10 mg/L,色度小于30度,浊度小于1 NTU,SDI15小于3,满足反渗透系统进水水质要求;MBR系统出水水质稳定,具有较强的耐冲击负荷能力。另外,探讨了MBR系统的跨膜压差与膜通量之间的关系。     

一体式平板膜生物反应器处理维生素制药废水中试研究

采用规模为5 m~3·h~(-1)左右的一体式平板膜生物反应器对维生素制药废水进行了中试研究.试验结果表明,用此装置处理维生素制药废水,出水水质稳定良好.工艺对COD和NH_4~+-N的去除率分别达到80%和90%以上,出水完全达到了发酵类制药工业水污染物排放标准(GB21903-2008)的排放要求;当HRT分别取12,22、26h时,对系统去除率有较大的影响;污泥浓度是影响膜通量的一个重要因素,污泥质量浓度应控制在7 g·L~(-1)左右;虽然污泥的沉降性能非常差,SV平均值为97.8%,但由于膜的高效截留作用,反应器不受污泥的性状的影响.     

运行工况对膜生物反应器内污泥特性的影响

探讨了膜生物反应器的运行工况对MBR内胞外聚合物(EPs)及污泥特性的影响,试验结果表明:污泥负荷№增加,污泥EPs降低,Zeta电位值降低.沉降性能变好,活性增加;曝气量增加,污泥EPs降低,Zeta电位值降低,沉降性能变好,活性先增加后降低;pH值由酸性变为碱性,污泥EPs增加,Zeta电位值增加.沉降性能先变好后...     

一体式膜生物反应器处理蛋白类废水研究

以一体式膜生物反应器 ,对较高浓度的蛋白类有机废水进行处理。结果表明 ,一体式膜生物反应器处理蛋白类废水效率高 ,不受负荷影响 ,进水COD在 6 2 3.4— 2 313.5mg/L之间 ,稳定运行条件下 ,COD的去除率可达 95 .0 %以上、TN的平均去除率为 6 1.8%、浊度的去除率可达 98.8%。通过密闭反冲洗系统、曝气紊流条件 ,可有效缓解膜通量的衰减 ,同时防止反应器内硝化抑制作用的产生。实验还表明 ,MLSS是制约膜水通量和废水处理效果的关键因素     

一体式新型PVC材料膜生物反应器处理生活污水的研究

利用一套一体式新型PVC(Polyvinyl chloride)材料膜生物反应器,采用模拟生活污水,研究了该新型材料膜生物反应器长期的运行特性、膜污染阻力分布及膜污染清洗方法.结果表明,PVC新型材料膜生物反应器对主要污染物SS、COD、NH4+-N和浊度等有很好的去除效果,出水的去除率分别可以稳定在99%,90%、95%和99%以上,TN去除率稍有波动,但大部分时间稳定在70%以上,出水水质可达到城市杂用水水质标准(GB/T 18920-2002)的要求.通过质量分数0.2%次氯酸钠碱洗和质量分数1%柠檬酸洗可以有效清除膜污染,使膜通量恢复至新膜水平.膜阻力分布分析表明泥饼层阻力和浓差极化阻力是膜污染的主要组成部分,占总阻力的88.59%,而内部阻力仅占3.65%.     

一体式膜生物反应器膜污染研究

膜生物反应器(MBR)是一种新型污水处理器,对生活污水处理效果显著,在使用过程中不可避免地会产生污染。为此,对膜生物反应器处理模拟生活污水的膜污染和清洗方法进行了研究,通过红外光谱分析了活性污泥性质的变化,利用扫描电镜分析了中空纤维膜表观结构的变化,探讨了膜污染的机理。结果表明,细菌滋生和污泥沉积造成了膜污染,泥饼层阻力占膜总阻力的89.86%,是膜污染的主要组成部分,水力清洗结合化学清洗可以很好地恢复膜的比通量。     

污泥形态变化对膜生物反应器处理性能及膜污染的影响

通过对膜生物反应器(MBR)系统中污泥颗粒变化和处理模拟废水水质的监测,考察了污泥形态变化对MBR处理性能和膜污染的影响。结果表明:MBR中颗粒有保持均匀分布并缓慢减小的趋势,颗粒大小对COD去除有一定影响,对氮磷的去除影响甚微,但是会加速膜污染。     

活性炭/粉煤灰处理含铜废水的研究

采用活性炭/粉煤灰处理模拟含铜废水,考察pH、吸附时间、吸附温度、投加量、质量比、活性炭、粉煤灰粒径、铜离子浓度等对吸附效果的影响。结果表明,单纯粉煤灰的吸附效果较差,但100目的粉煤灰与100目的活性炭混合,其吸附效果接近于纯活性炭。活性炭/粉煤灰处理100 m L、30 mg/L模拟含铜废水的最佳吸附条件为:吸附时间3 h,pH 6,吸附温度45℃,活性炭/粉煤灰(质量比1∶1)投加量2.5 g,活性炭和粉煤灰粒径均为100目。在此条件下,铜离子去除率可达97.33%,处理后水中铜离子浓度(0.811 4 mg/L)低于国家二级排放标准(1.0 mg/L)。     

活性炭/粉煤灰处理含铜废水的研究

采用活性炭/粉煤灰处理模拟含铜废水,考察pH、吸附时间、吸附温度、投加量、质量比、活性炭、粉煤灰粒径、铜离子浓度等对吸附效果的影响。结果表明,单纯粉煤灰的吸附效果较差,但100目的粉煤灰与100目的活性炭混合,其吸附效果接近于纯活性炭。活性炭/粉煤灰处理100 m L、30 mg/L模拟含铜废水的最佳吸附条件为:吸附时间3 h,pH 6,吸附温度45℃,活性炭/粉煤灰(质量比1∶1)投加量2.5 g,活性炭和粉煤灰粒径均为100目。在此条件下,铜离子去除率可达97.33%,处理后水中铜离子浓度(0.811 4 mg/L)低于国家二级排放标准(1.0 mg/L)。     

活化增钙粉煤灰对水泥性能的影响

测试了将增钙粉煤灰物理活化或化学活化后作混合材,水泥在凝结时间、安定性、强度方面的变化。结果表明:利用化学活化和物理活化对增钙粉煤灰进行改性可提高其极限掺量,同时改善其安定性,水泥强度得到有效提高。     

Influence of trace metal distribution on its leachability from coal fly ash

The risks associated with the reuse of coal fly ash in natural environmental settings in terms of their mobility and ecotoxicological significance is largely determined by: (1) the physicochemical conditions the fly ash is placed under; (2) the total leachable metal content in fly ash and; (3) the distribution or mineralogical fractionation of metals. In this study, we report the mobility of As, Cr, Pb, Fe, Cu and Zn from a single Class F fly ash (CFFA). The influence of pH on metal release was compared to the total leachable metal content, as determined by single and sequential chemical extractions. The results show that the CFFA sample is environmentally safe under natural pH conditions, with metal leaching less than the mandated RCRA limits. The elements Fe, Pb and Cr were moderately soluble at acidic pH and sparingly soluble beyond neutral pH. Arsenic release from CFFA was higher under aggressive pH conditions (pH < 4 and pH > 9) and consistent with its oxyanionic behavior. Partial dissolution of the acid soluble (exchangeable) fraction at acidic pH; desorption of oxyanions at alkaline pH; adsorption and or co-precipitation of metals with iron (hydr) oxides at neutral pH appeared to be the probable mechanisms controlling metal release. While simple EDTA extractions provided good indications of the total leachable amounts, a direct correlation with pH leaching data was impossible as the mineralogical distribution of the metals in the fly ash appeared to play a significant role in their leachability. In the case of Class F fly ash, metal association with Fe-oxide appeared to play a more dominant role in metal release.     

活化煤矸石与粉煤灰制备复合水泥的正交实验研究

利用正交实验分析了活化煤矸石与粉煤灰制备复合水泥的力学性能,对双掺活化煤矸石与粉煤灰超叠复合效应进行了探讨。结果表明,对28天抗折抗压强度影响显著的因素依次为活化煤矸石与粉煤灰的总掺量、碱激发剂、活化煤矸石与粉煤灰的配合比、石膏掺量,其中总掺量为30％,活化煤矸石：粉煤灰=7：3,石膏掺量为7％时,其功效系数最高,当活化煤矸石与粉煤灰的总掺量为30％时。对3d、28d抗折抗压强度活化煤矸石与粉煤灰有一个最佳的配合比。     

Volatility of fly ash and coal

The volatilization of fly ash has been examined by a number of techniques including TGA—DTA, Knudsen cell mass spectrometry, volatilization of neutron-activated fly ash, and X-ray fluorescence analysis of sized fly ash, low-temperature ash, and the parent coal. At low temperatures, H₂O, CO₂, SO₂, and a number of organic compounds are the primary volatile species as determined by mass spectrometry. Analysis of the volatiles collected from activated fly ash heated to temperatures up to 1400 °C shows that Hg, Se, As, Br, and I are nearly completely volatilized. The analysis of the bulk and size fractions of fly ash, and parent coal, is consistent with this and provides evidence for volatilization of 15 elements during coal combustion. Comparison of coal and fly ash compositions also shows that significant amounts of Se are still present in the gas phase at the precipitators and more than 50 wt % of the Se is contained in the stack emissions. The results are consistent with present models for fly ash formation and trace element enrichment.     

粉煤灰农业利用研究进展

评述粉煤灰农业利用研究进展情况,并讨论其中存在的问题.对未来研究工作进行了展望.     

Alkali-aggregate reaction in activated fly ash systems

Certain aspects of the durability of a new cementitious material, alkali activated fly ash, are addressed in this article; specifically, a series of findings relating to the alkali-silica reaction are reported. The approach adopted in the study was to compare the new cementitious systems to analogous Portland cement mortars using aggregates of differing reactivity and a procedure based on the test described in ASTM standard C 1260. The results of SEM/EDX and XRD analysis of the materials showed that activated fly ash mortars performed better than the Portland cement equivalents.     

Corrosion resistance in activated fly ash mortars

The question of whether reinforcing steel can be protected with activated fly ash cement as effectively as with Portland cement is explored in this study. Corrosion potential (E_corr) and polarisation resistance (R_p) values for steel electrodes embedded in Portland cement mortar and two fly ash mortars, respectively activated with NaOH and waterglass+NaOH solutions, are monitored. Chloride-free activated fly ash mortars are found to passivate steel reinforcement as speedily and effectively as Portland cement mortars, giving no cause to fear that corrosion may limit the durability of reinforced concrete structures built with these new types of activated fly ash cement. The polarisation curves and the response to short-term anodic current pulses (galvanostatic pulse technique) obtained further corroborate the full and stable passivation of the steel by the concrete manufactured with these binders.