• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Performance of a double-layer BAF using zeolite and ceramic as media under ammonium shock load condition

    2014-03-06 06:21:56XinleiZHAOLiangZHUShijieBAIMingZHOUJingQIANWeiWU
    Water Science and Engineering 2014年1期
    關鍵詞:原文

    Xin-lei ZHAO, Liang ZHU* Shi-jie BAI, Ming ZHOU Jing QIAN Wei WU

    1. College of Environment, Hohai University, Nanjing 210098, P. R. China

    2. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, P. R. China

    3. Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes,

    Ministry of Education, Hohai University, Nanjing 210098, P. R. China

    4. Yellow River Engineering Consulting Co., Ltd., Zhengzhou 450003, P. R. China

    5. Wujin Water Resources Bureau, Changzhou 213172, P. R. China

    Performance of a double-layer BAF using zeolite and ceramic as media under ammonium shock load condition

    Xin-lei ZHAO1,3,4, Liang ZHU*1,2,3, Shi-jie BAI5, Ming ZHOU1,3, Jing QIAN1,3, Wei WU1,3

    1. College of Environment, Hohai University, Nanjing 210098, P. R. China

    2. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, P. R. China

    3. Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes,

    Ministry of Education, Hohai University, Nanjing 210098, P. R. China

    4. Yellow River Engineering Consulting Co., Ltd., Zhengzhou 450003, P. R. China

    5. Wujin Water Resources Bureau, Changzhou 213172, P. R. China

    An experiment was carried out to investigate the anti-ammonium shock load capacity of a biological aerated filter (BAF) composed of a double-layer bed. This bed was made up of a top layer of ceramic and a bottom layer of zeolite. The experiment shows that the anti-ammonium shock load process can be divided into two processes: adsorption and release. In the adsorption process, the total removal efficiency of ammonia nitrogen by zeolite and ceramic was 94%. In the release process, the ammonia nitrogen concentration increased significantly and then gradually returned to the normal level four hours after the shock load. The results indicated that the double-layer BAF had a high level of adaptability to the short-term ammonium shock load and long-term operation. The main factors influencing the dynamic process of ammonia nitrogen adsorption were the filter bed height, ammonia nitrogen concentration of influent, and flow rate. The bed depth service time (BDST) model was used to predict the relationship between the filter bed height and breakthrough time at different flow rates, and the results are reliable.

    biological aerated filter (BAF); zeolite; ceramic; ammonia nitrogen; shock load; dynamic adsorption

    1 Introduction

    Biological aerated filters (BAFs) have been widely used because of their high performance, small footprint, easy management system, and high loading capability (Ma and Qiu 2002; Halle et al. 2009; Huang et al. 2011). Media used in BAFs play a significant role in wastewater treatment. The characteristics of these media not only are related to the initial investment, process design, and operation mode of BAFs, but also affect the daily running cost (Zhang et al. 2002; Han et al. 2009; Qiu et al. 2010). Zeolite has high porosity and a large specific surface area, and its strong ability to adsorb ammonia nitrogen (4NH-N+) can lead to areduction in the impact of the ammonium shock load on water quality (Tsuno et al. 1994; Lahav and Green 1998; Rozic et al. 2000; He et al. 2007). In addition, saturated zeolite can be reused for adsorption (Xu and Zhou 2003; Liu et al. 2005; Tian et al. 2002a). The removal efficiency of ammonia nitrogen affected by hydraulic loading is relatively low in a zeolite biological aerated filter at low temperatures (Tian et al. 2002b; Tao et al. 2005). Ceramic has the advantages of excellent properties of biofilm formation, low-temperature resistance, and high efficiency (Jiang and Hu 2002; Sang and Wang 2003). The combination of zeolite and ceramic has an advantage over either of the two media alone in the remediation of ammonium contaminants.

    This paper describes the application of a BAF using zeolite and ceramic as media in wastewater treatment. Wastewater prepared by dilution of domestic sewage was fed into the upflow BAF. The performance of the BAF with zeolite and ceramic media under the conditions of normal and shock ammonium loads was observed. The aim of this study was to examine the ammonia nitrogen variation before and after the shock load in the reactor and to provide a reference for practical applications of double-layer BAFs.

    2 Materials and methods

    2.1 Wastewater characteristics

    The test water was prepared by dilution of domestic sewage, to the point that it reached the water quality requirements for tail water from sewage treatment plants (secondary effluent). The characteristics of wastewater during the experimental period were as follows: the ammonia nitrogen concentration was 8.32 mg/L, the nitrate nitrogen (3NO-N?) concentration was 0.33 mg/L, and the nitrite nitrogen (2NO-N?) concentration was 0.32 mg/L.

    2.2 Experimental setup

    The experimental BAF was made of acrylic. The filter had a diameter of 0.12 m and a height of 2 m. The schematic diagram of the reactor is shown in Fig. 1. The reactor had an upflow configuration, and the pipes used for the influent and backwash water as well as air distribution were set at the bottom.

    Fig. 1 Schematic diagram of BAF experimental system

    2.3 Anti-ammonium shock load test

    During the anti-ammonium shock load test, zeolite and ceramic were the media of the double-layer filter: the 0.7 m-high bottom layer was made of zeolite with a particle size ranging from 5 to 10 mm, and the 0.7 m-high top layer was made of ceramic with a particle size ranging from 3 to 5 mm. Along the totally 1.4 m-high filter layer, nine sampling points were set, from #0 at the bottom to #8 at the top, and the interval between adjacent sampling points was 0.175 m. Meanwhile, the water at the #0 and #8 sampling points was considered influent and effluent water, respectively. At the bottom of the reactor, a 0.1 m-high gravel layer with a particle size ranging from 2 to 3 cm was laid to support the filter media. In the upflow BAF, the air was introduced into the reactor with a micro-bubble air diffuser and the air flow rate was controlled with an air flow meter.

    The anti-ammonium shock load test ran a week under the following conditions: the influent hydraulic loading was 0.7 m/h, the volume ratio of gas to water was 3:1, the chemical oxygen demand (COD) concentration was 27.97 mg/L, and the ammonia nitrogen concentration was 8.32 mg/L. The ammonium shock load was set at 50 mg/L, considering that the normal ammonia nitrogen concentration of sewage treatment plants was approximately 50 mg/L. The ammonium shock load persisted for 1.5 hours per day. The concentrations of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen under the normal condition and during the four hours after the ammonium shock load were measured, and the average values over one week were analyzed. The ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen concentrations were analyzed using standard methods (SEPAC 2002).

    2.4 Fitting model for dynamic adsorption test

    During the dynamic adsorption test, a certain amount of zeolite was laid in the adsorption column, whose diameter was 8 cm and whose height was 30 cm. Ammonia nitrogen wastewater with a concentration of 60 mg/L was provided through the zeolite bed at a flow rate of 0.7 m/h, and the effluent ammonia nitrogen concentration was measured.

    The dynamic adsorption process of ammonia nitrogen was predicted using the bed depth service time (BDST) model (Bohart and Adams 1920; Hutchins 1973; Raúl et al. 2009). The equations used in the BDST model are

    where0C is the influent concentration (mg/L),tC is the effluent concentration at time t (mg/L),0N is the adsorbed amount calculated using the fitting model (mg/L),ak is the rate constant (L/(min·mg)), Z is the height of the filter layer (cm), F is the water flow velocity (cm/min), and t is the run time of the system (min).

    3 Results and discussion

    3.1 Analysis of anti-ammonium shock load test process

    The anti-ammonium shock load test can be divided into two processes: adsorption and release. The reaction equilibrium equation is

    where BZ is the processed zeolite and ceramic, and B is the exchangeable cation in the zeolite.

    When the ammonium concentration in the liquid phase was higher than that in the zeolite, the ion exchange equilibrium tended to be rightward so that ammonium was removed through ion exchange. This process is called adsorption. When the ammonium concentration in the liquid phase was lower than that in the zeolite, the ammonium that was stored in the organisms was released into the liquid phase, and the adsorption capacity of zeolite was regenerated at the same time. This process is called the release process. Table 1 shows the influent and effluent ammonia nitrogen concentrations under the normal and shock load conditions and during the four hours after the ammonium shock load. Under the normal load condition, the influent ammonia nitrogen concentration was 8.32 mg/L, the effluent ammonia nitrogen concentration was 3.05 mg/L, and the ammonia nitrogen removal efficiency was 63%. The effluent ammonia nitrogen concentration remained at about 3 mg/L four hours after the shock load, so the zeolite and ceramic BAF was efficient in wastewater treatment and had a relatively strong capability to resist the shock load.

    Table 1 Influent and effluent 4NH-N+ concentrations under different conditions

    3.1.1 Adsorption process during anti-ammonium shock load test

    The variation tendency of the ammonia nitrogen concentration under the normal and shock load conditions in the filter is shown in Fig. 2. Under the normal load condition, the ammonia nitrogen removal rate was 63%, and the ammonia nitrogen removal mainly occurred in the filter segment with a height ranging from 35 to 105 cm (the bottom of the zeolite layer was set to 0 cm), accounting for 74% of the total removal. Under the shock load condition, the influent ammonia nitrogen concentration was 58.49 mg/L and the effluent was 3.57 mg/L, so the total removal rate was 94%, and the removal mainly occurred in the zeolite segment with a height from 0 to 35 cm, accounting for 84% of the total.

    The amount of ammonium adsorbed by the zeolite and ceramic layers under the shock load condition was calculated with the equation below:

    whereZW is the ammonium adsorption capacity of the zeolite layer (mg),TW is the total amount of removed ammonia nitrogen (mg), andmW is the amount of ammonia nitrogen removed due to biological function (mg).

    Fig. 2 Removal performance of 4NH-N+ , 3NO-N? , and 2NO-N? under different load conditions

    The amount of removal of ammonium due to the action of microorganisms can be characterized by the average amount of ammonia nitrogen removed by the action of microorganisms during the total run process. The amount of ammonia nitrogen removal at each sampling point is shown in Fig. 2(a). It was calculated thatTW= 532.82 mg,mW= 20.51 mg, andZW= 512.31 mg, and the adsorption amount accounted for 96.15% of the total. The result revealed that the short-time ammonium shock load did not lead to a large population of nitrifying bacteria, and ammonia nitrogen was removed mainly by adsorption exchange of zeolite.

    Fig. 2(b) shows that the concentrations of nitrate nitrogen and nitrite nitrogen changed similarly under the shock load and normal load conditions. Under the shock load condition, the increasing values of the nitrate nitrogen and nitrite nitrogen concentrations were 0.65 mg/L and 0.66 mg/L, respectively, in the 0 to 35 cm-high (#2) filter layer when the ammonia nitrogen removal concentration was 46.21 mg/L.

    Under the normal ammonium load condition, the nitrate nitrogen and nitrite nitrogen concentrations increased slowly in the 0 to 35 cm-high filter layer and increased rapidly in the filter layer above a height of 35 cm, the nitrite nitrogen concentration peaked at a height of 87.5 cm (#5), and then decreased gradually, and the nitrate nitrogen concentration continued to increase. Compared with concentrations under the normal load condition, the nitrite nitrogen concentration was higher at the sampling points along the filter layer under the shock load condition, due to the increase of ammonia nitrogen concentration. The nitrate nitrogen concentration increased slightly because of the increase of the nitrite concentration.

    The variation of the nitrifying capacity along the filter (Fig. 3) showed that nitrifying bacteria were active in the system. In the 0 to 35 cm-high filter layer, the organic load was higher, and the heterotrophic bacteria were the dominant strain. The activity of the autotrophicnitrobacteria was inhibited, so nitrification contributed little in the total removal of ammonia nitrogen and the nitrate nitrogen and nitrite nitrogen concentrations increased slowly. In the 35 to 140-cm filter layers, with the decrease of the organic load of the system, the number of heterotrophic bacteria decreased and nitrification increased, so the nitrate and nitrite nitrogen concentrations increased rapidly. In the 87.5 (#5) to 140 cm-high filter layer, the nitrite nitrogen concentration decreased with the ongoing nitrification.

    Fig. 3 Nitrifying capacity at each sampling point under normal load condition

    3.1.2 Release process during anti-ammonium shock load test

    Fig. 4 Variation of 4NH-N+ , 3NO-N? , and 2NO-N? concentrations under different load conditions

    After the shock load, the ammonia nitrogen concentration decreased (Fig. 4), and the ion exchange in Eq. (3) processed toward the left. The ammonia nitrogen adsorbed by zeolite wasreleased into the liquid phase, so the ammonia nitrogen concentration in the filter was higher than that in the influent. The operation scheme of the filter was upward flow, so the zeolite at the bottom was exposed to the ammonium shock load for the longest time and adsorbed the largest amount of ammonia nitrogen. With the increase of time the peak of ammonia nitrogen had an upward trend, and gradually decreased. Four hours after the shock load, the ammonia nitrogen concentration almost returned to the normal level. The ammonia nitrogen released into the liquid phase was removed by nitrification, and the zeolite was recycled.

    Figs. 4(b) and 4(c) respectively show the variations of the nitrate nitrogen and nitrite nitrogen concentrations along the filter with different ammonium loads. With the decrease of the ammonia nitrogen concentration, the nitrate nitrogen concentrations increased over time, and the nitrite nitrogen concentration peaked at #5, then decreased gradually, and eventually returned to the level similar to that under the normal load conditions.

    3.2 Simulation of ammonium dynamic adsorption test

    The dynamic adsorption test results show that nitrogen adsorption was not good if the filter bed was not high (Fig. 5). When the filter bed height increased, the hydraulic retention time increased and the ammonia nitrogen could be more fully adsorbed, with the result that the breakthrough time of ammonia nitrogen increased. Fig. 6 shows the relationship between time and filter bed height with0tC C values of 0.18, 0.25, and 0.55. The results show that the values of all the correlation coefficients (R) of the fitting curves are more than 0.9, indicating that the BDST model is applicable to the adsorption system. The kinetic parameters of the BDST model were obtained from the slope a and intercept b of the fitting curves, and the results are shown in Table 2.

    Fig. 6 Relationship between time and filter bed height with different 0tC C values

    Table 2 Calculated constants of BDST model

    Table 2 shows that with the increase of the CtC0value, the rate constant kadecreased and the adsorbed amount N0increased. The effluent quality of the filter under the ammonium shock load condition was predicted using the BDST model. According to the fitting curves, when CtC0= 0.25, that is, Ct=15 mg/L and t = 6.64Z?21.67, a breakthrough time of t = 94.53 min was obtained at Z = 17.5 cm. It was found that when Ct=14.73 mg/L and Z = 17.5 cm, the measured breakthrough time was t = 98 min. The prediction error is small, so the BDST model is applicable to forecasting of the breakthrough time.

    4 Conclusions

    (1) The anti-ammonium shock load capacity of a zeolite-ceramic BAF was studied. It was found that the anti-ammonium shock load test process can be divided into two processes: adsorption and release. The adsorption occurred when the ammonia nitrogen concentration in the liquid phase was higher than that in the zeolite and ceramic. When the influent ammonia nitrogen concentration in the experiment was 58.49 mg/L, the total removal rate was 94%, which mainly occurred in the 0 to 35-cm zeolite segment, accounting for 84% of the total. In the release process, the ammonia nitrogen concentration increased first and then decreased along the filter. Along with time, the peak of the ammonia nitrogen concentration moved from the top to the bottom of the filter and gradually decreased. Four hours after the shock load, the effluent ammonia nitrogen concentration almost returned to the normal level.

    (2) Under the normal load condition when the influent ammonia nitrogen concentration was 8.32 mg/L, the nitrate nitrogen concentration was 0.33 mg/L, and the nitrite nitrogen concentration was 0.32 mg/L, the ammonia nitrogen removal rate was 63%, with a removal rate of 47% in the 35 to 105 cm-high filter layer, accounting for 74% of the total removal.

    (3) Studies on the anti-ammonium shock load test show that the double-layer BAF using zeolite and ceramic as media had a strong anti-ammonium shock load capacity. The effluent ammonia nitrogen concentration was always less than 4 mg/L during the anti-ammonium shock load test process when the influent ammonia nitrogen concentration was 58.49 mg/L.

    (4) Results of the dynamic adsorption test show that the higher the filter bed is, the more favorable it is for the adsorption of ammonia nitrogen. Meanwhile, the BDST model was able to reliably predict dynamic adsorption of ammonia nitrogen by zeolite.

    Bohart, G., and Adams, E. N. 1920. Some aspects of the behavior of charcoal with respect to chlorine. Journal of the Franklin Institute, 189(5), 523-544. [doi:10.1021/ja01448a018]

    Halle, C., Huck, P. M., Peldszus, S., Haberkamp, J., and Jekel, M. 2009. Assessing the performance of biological filtration as pretreatment to low pressure membranes for drinking water. Environmental Science and Technology, 43(10), 3878-3884. [doi:10.1021/es803615g]

    Han, S. Q., Yue, Q. Y., Yue, M., Gao, B. Y., Zhao, Y. Q., and Cheng, W. J. 2009. Effect of sludge-fly ash ceramic particles (SFCP) on synthetic wastewater treatment in an A/O combined biological aerated filter. Bioresource Technology, 100(3), 1149-1155. [doi:10.1016/j.biortech.2008.08.035]

    He, S. B., Xue, G., and Kong, H. N. 2007. The performance of BAF using natural zeolite as filter media underconditions of low temperature and ammonium shock load. Journal of Hazardous Materials, 143(1-2), 291-295. [doi:10.1016/j.jhazmat.2006.09.024]

    Huang, G. C., Meng, F. G., Zheng, X., Wang, Y., Wang, Z. G., Liu, H. J., and Jekel, M. 2011. Biodegradation behavior of natural organic matter (NOM) in a biological aerated filter (BAF) as a pretreatment for ultrafiltration (UF) of river water. Applied Microbiology and Biotechnology, 90(5), 1795-1803. [doi: 10.1007/s00253-011-3251-1]

    Hutchins, R. A. 1973. New simplified design of activated carbon system. American Journal of Chemical Engineering, 80, 133-138.

    Jiang, P., and Hu, J. C. 2002. Research on the homemade light granular ceramics used in BAF. Acta Scientiae Circumstantiae, 22(4), 459-464. (in Chinese) [doi:10.3321/j.jssn:0253-2468.2002.04.009]

    Lahav, O., and Green, M. 1998. Ammonium removal using ion exchange and biological regeneration. Water Research, 32(7), 2019-2028. [doi:10.1016/S0043-1354(97)00453-3]

    Liu, J. X., Lou, J. S., and Chen, C. N. 2005. Zeolite biological aerated filter for treatment of micro-polluted source water. China Water and Wastewater, 21(6), 38-40. (in Chinese) [doi:10.3321/j.jssn:1000-4602. 2005.06.011]

    原文:I’m pretty much totally and completely petrified.

    Ma, J., and Qiu, L. P. 2002. Biological aerated filter and its research progress. Environmental Engineering, 20(3), 7-11. (in Chinese) [doi:10.3969/j.jssn.1000-8942.2002.03.001]

    Qiu, L. P., Zhang, S. B., Wang, G. W., and Du, M. A. 2010. Performances and nitrification properties of biological aerated filters with zeolite, ceramic particle and carbonate media. Bioresource Technology, 101(19), 7245-7251. [doi:10.1016/j.biortech.2010.04.034]

    Raúl, C. M., Marcos, S. R., Veronica, M. M., and Ruth, A. C. 2009. Removal of cadmium by natural and surfactant-modified mexican zeolitic rocks in fixed bed columns. Water, Air, and Soil Pollution, 196(1-4), 199-210. [doi:10.1007/s11270-008-9769-x]

    Rozic, M., Cerjan-Stefanovic, S., Kurajica, S., Vancina, V., and Hodzic, E. 2000. Ammoniacal nitrogen removal from water by treatment with clay and zeolites. Water Research, 34(14), 3675-3681. [doi:10. 1016/S0043-1354(00)00113-5]

    Sang, J. Q., and Wang, Z. S. 2003. Performance of bio-ceramic reactor at low temperature. Chinese Journal of Environmental Science, 24(2), 112-115. (in Chinese) [doi:10.3321/j.jssn:0250-3301.2003.02.022]

    Tao, T. T., Zhang, Y. X., and Wang, S. 2005. Nitrogen removal of municipal wastewater by using of zeolite medium biological aerated filter. Water and Wastewater Engineering, 31(10), 36-39. (in Chinese)

    Tian, W. H., Wen, X. H., and Qian, Y. 2002a. Characteristics of zeolite media biological aerated filter during start-up. Techniques and Equipment for Environmental Pollution Control, 3(12), 38-42. (in Chinese)

    Tian, W. H., Wen, X. H., and Qian, Y. 2002b. Use of zeolite medium biological aerated filter for removal of COD and ammonia nitrogen. China Water and Wastewater, 18(12), 13-15. (in Chinese)

    Tsuno, H., Nishimura, F., and Somiya, I. 1994. Removal of ammonium nitrogen in bio-zeolite reactor. Doboku Gakkai Rombun Hokokulshu, 5(3), 159-166.

    Xu, L. H., and Zhou, Q. 2003. Use of zeolite for NH3-N removal from wastewater and its regeneration. China Water and Wastewater, 19(3), 24-26. (in Chinese) [doi:10.3321/j.jssn:1000-4602.2003.03.008]

    Zhang, J., Cao, X. S., and Meng, X. Z. 2012. Progress in the study of aerated biofilter. China Water and Wastewater, 18(8), 26-29. (in Chinese) [doi:10.3321/j.jssn:1000-4602.2002.08.008]

    (Edited by Yun-li YU)

    ——

    This work was supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China (Grant No. 2009ZX07317).

    *Corresponding author (e-mail: zhulianghhu@163.com)

    Received Nov. 11, 2012; accepted Apr. 7, 2013

    猜你喜歡
    原文
    Definition, Mission and Standards of International Olive Council (英文原文)
    Omega-6 for Body, Omega-3 for Brain: Balance for Brain Development in Children (英文原文)
    Developing ISO International Standards for the Animal and Vegetable Fats and Oils Sector (英文原文)
    The Role of the American Oil Chemists’Society in World Trade
    ——Quality Assurance Testing, Certified Reference Materials, and International Liaison Activities (英文原文)
    讓句子動起來
    豐 碑
    嘗糞憂心
    哭竹生筍
    扼虎救父
    恣蚊飽血
    久久久久国产精品人妻aⅴ院| 免费人成视频x8x8入口观看| 国产av一区二区精品久久| 亚洲精品中文字幕在线视频| 99国产精品一区二区三区| 成人欧美大片| 一本精品99久久精品77| 国产激情久久老熟女| 黄色片一级片一级黄色片| 精品欧美国产一区二区三| 久久久久九九精品影院| 色播亚洲综合网| 18禁美女被吸乳视频| 国产一卡二卡三卡精品| 国产精品久久久久久精品电影 | 亚洲自拍偷在线| 久久久国产欧美日韩av| 无遮挡黄片免费观看| 国产又色又爽无遮挡免费看| 2021天堂中文幕一二区在线观 | 精品午夜福利视频在线观看一区| 国产片内射在线| 两个人看的免费小视频| 观看免费一级毛片| 99国产精品99久久久久| 好看av亚洲va欧美ⅴa在| 岛国在线观看网站| 国产精品98久久久久久宅男小说| 夜夜看夜夜爽夜夜摸| 自线自在国产av| 免费看a级黄色片| 在线视频色国产色| 亚洲va日本ⅴa欧美va伊人久久| 色婷婷久久久亚洲欧美| 日本熟妇午夜| 麻豆成人av在线观看| 精品国产亚洲在线| 午夜激情av网站| 精品不卡国产一区二区三区| 日韩欧美 国产精品| 一进一出抽搐gif免费好疼| 亚洲精品中文字幕在线视频| ponron亚洲| www日本黄色视频网| 国产又爽黄色视频| 少妇被粗大的猛进出69影院| 国产精品免费一区二区三区在线| 日韩 欧美 亚洲 中文字幕| 国产精品久久久人人做人人爽| 亚洲成av片中文字幕在线观看| 黄色视频不卡| 午夜福利免费观看在线| 亚洲精品中文字幕一二三四区| 99久久无色码亚洲精品果冻| 精品免费久久久久久久清纯| 老鸭窝网址在线观看| 亚洲av熟女| 国产亚洲av嫩草精品影院| 久久久国产成人免费| 免费在线观看成人毛片| 桃色一区二区三区在线观看| 色av中文字幕| √禁漫天堂资源中文www| www.精华液| 欧美久久黑人一区二区| 中文字幕久久专区| 色婷婷久久久亚洲欧美| 国产精品98久久久久久宅男小说| 熟女电影av网| 国产99白浆流出| 久久欧美精品欧美久久欧美| 日韩精品青青久久久久久| 国产av在哪里看| 亚洲成人精品中文字幕电影| 色综合亚洲欧美另类图片| 亚洲av成人av| 俄罗斯特黄特色一大片| 久久精品成人免费网站| 99riav亚洲国产免费| 午夜激情福利司机影院| 国产视频内射| 国产v大片淫在线免费观看| 伦理电影免费视频| 亚洲中文日韩欧美视频| 亚洲专区字幕在线| 亚洲欧美精品综合一区二区三区| 999久久久国产精品视频| 亚洲国产毛片av蜜桃av| 久久精品国产亚洲av香蕉五月| 国产欧美日韩精品亚洲av| 亚洲aⅴ乱码一区二区在线播放 | 1024视频免费在线观看| 国产精品美女特级片免费视频播放器 | 国产成人啪精品午夜网站| 99国产综合亚洲精品| 真人一进一出gif抽搐免费| 欧美成人一区二区免费高清观看 | 国产亚洲精品久久久久久毛片| 午夜日韩欧美国产| 中文资源天堂在线| 白带黄色成豆腐渣| 少妇粗大呻吟视频| 欧美av亚洲av综合av国产av| 久久天堂一区二区三区四区| 欧美日韩中文字幕国产精品一区二区三区| 国产亚洲精品久久久久5区| 国产精品精品国产色婷婷| 日日干狠狠操夜夜爽| 桃红色精品国产亚洲av| 国产成人av教育| 亚洲国产精品久久男人天堂| 男女那种视频在线观看| 国产成+人综合+亚洲专区| 成人特级黄色片久久久久久久| 嫩草影视91久久| 久久婷婷人人爽人人干人人爱| 免费电影在线观看免费观看| 琪琪午夜伦伦电影理论片6080| 亚洲中文av在线| 夜夜爽天天搞| 麻豆国产av国片精品| 亚洲成a人片在线一区二区| xxx96com| 色婷婷久久久亚洲欧美| 一区二区三区激情视频| 国产三级在线视频| 十八禁网站免费在线| 成人午夜高清在线视频 | 黑人巨大精品欧美一区二区mp4| 成人国产一区最新在线观看| 男人舔女人下体高潮全视频| 国产一区二区在线av高清观看| 亚洲av日韩精品久久久久久密| 国产伦人伦偷精品视频| 一区二区三区精品91| 久久久国产成人精品二区| 丰满人妻熟妇乱又伦精品不卡| 亚洲av片天天在线观看| 变态另类成人亚洲欧美熟女| 成人国产一区最新在线观看| 婷婷六月久久综合丁香| 色综合站精品国产| 精品久久久久久久末码| 亚洲免费av在线视频| 怎么达到女性高潮| 老司机在亚洲福利影院| 男女午夜视频在线观看| 国产精品免费一区二区三区在线| 狠狠狠狠99中文字幕| 一区二区三区精品91| 人妻久久中文字幕网| 日本一本二区三区精品| 国产成+人综合+亚洲专区| 欧美一区二区精品小视频在线| 久久精品夜夜夜夜夜久久蜜豆 | 国产野战对白在线观看| 男女床上黄色一级片免费看| 国产成人精品无人区| 嫁个100分男人电影在线观看| 免费看日本二区| 免费观看精品视频网站| 又黄又爽又免费观看的视频| 欧美亚洲日本最大视频资源| 男女午夜视频在线观看| 啦啦啦 在线观看视频| 亚洲aⅴ乱码一区二区在线播放 | 十分钟在线观看高清视频www| 成人18禁在线播放| 亚洲中文日韩欧美视频| 亚洲人成网站在线播放欧美日韩| 男女午夜视频在线观看| 一二三四社区在线视频社区8| 日韩欧美免费精品| 欧美日韩一级在线毛片| 国产久久久一区二区三区| 脱女人内裤的视频| 国产精品一区二区精品视频观看| 黄色 视频免费看| 婷婷六月久久综合丁香| 欧美日韩亚洲综合一区二区三区_| 1024手机看黄色片| 久久伊人香网站| www日本在线高清视频| av天堂在线播放| 免费电影在线观看免费观看| 久久久久久久精品吃奶| 国产精华一区二区三区| 久久久久精品国产欧美久久久| 窝窝影院91人妻| 久热爱精品视频在线9| 日本 av在线| 国产成人精品久久二区二区91| 亚洲一卡2卡3卡4卡5卡精品中文| 欧美中文综合在线视频| 老司机深夜福利视频在线观看| 成人av一区二区三区在线看| 中文字幕最新亚洲高清| 欧美久久黑人一区二区| 国产精品国产高清国产av| 亚洲真实伦在线观看| 久久久久久久久久黄片| 久久中文字幕人妻熟女| 1024手机看黄色片| 制服人妻中文乱码| 亚洲国产精品合色在线| 嫩草影视91久久| 国产精品二区激情视频| av超薄肉色丝袜交足视频| 日本撒尿小便嘘嘘汇集6| 久久国产精品人妻蜜桃| 美国免费a级毛片| 好男人电影高清在线观看| 欧美黄色片欧美黄色片| 免费看美女性在线毛片视频| 国产色视频综合| 亚洲男人的天堂狠狠| 免费在线观看视频国产中文字幕亚洲| 伊人久久大香线蕉亚洲五| 天堂√8在线中文| 在线观看午夜福利视频| 国产v大片淫在线免费观看| 国产伦在线观看视频一区| 午夜视频精品福利| 亚洲精品美女久久久久99蜜臀| 久久久久国内视频| 法律面前人人平等表现在哪些方面| 中文字幕精品免费在线观看视频| 亚洲专区中文字幕在线| 一二三四社区在线视频社区8| 禁无遮挡网站| 级片在线观看| 美女国产高潮福利片在线看| 国产亚洲精品第一综合不卡| 长腿黑丝高跟| 51午夜福利影视在线观看| 成年人黄色毛片网站| 日韩欧美在线二视频| 搞女人的毛片| 大型黄色视频在线免费观看| 久久久久久国产a免费观看| 最近最新免费中文字幕在线| 99久久综合精品五月天人人| 成人永久免费在线观看视频| 日韩欧美国产一区二区入口| 男女床上黄色一级片免费看| 国产亚洲欧美在线一区二区| 丝袜人妻中文字幕| 精品久久久久久成人av| 一本综合久久免费| 久久久久亚洲av毛片大全| 亚洲中文av在线| av福利片在线| 一级毛片女人18水好多| 中文亚洲av片在线观看爽| 国产成人系列免费观看| 亚洲性夜色夜夜综合| 夜夜夜夜夜久久久久| 国产熟女xx| 亚洲专区中文字幕在线| 天天添夜夜摸| 精品欧美一区二区三区在线| 亚洲va日本ⅴa欧美va伊人久久| 国产精品一区二区精品视频观看| 亚洲熟女毛片儿| 亚洲成av片中文字幕在线观看| 欧美人与性动交α欧美精品济南到| 精品第一国产精品| 动漫黄色视频在线观看| 亚洲片人在线观看| 性色av乱码一区二区三区2| 97超级碰碰碰精品色视频在线观看| 亚洲午夜理论影院| 99国产极品粉嫩在线观看| av在线天堂中文字幕| 99热6这里只有精品| 麻豆一二三区av精品| 97碰自拍视频| 嫩草影院精品99| 女警被强在线播放| 淫妇啪啪啪对白视频| 日韩欧美 国产精品| 亚洲av日韩精品久久久久久密| 亚洲人成电影免费在线| 久久国产亚洲av麻豆专区| 韩国精品一区二区三区| 欧美日韩亚洲综合一区二区三区_| 黄色片一级片一级黄色片| 亚洲午夜理论影院| 亚洲真实伦在线观看| 中文字幕另类日韩欧美亚洲嫩草| 国产单亲对白刺激| 手机成人av网站| 久久精品夜夜夜夜夜久久蜜豆 | 91成人精品电影| 中文字幕另类日韩欧美亚洲嫩草| 99久久综合精品五月天人人| 亚洲国产精品合色在线| 国产免费av片在线观看野外av| 日韩大码丰满熟妇| 国产成人av激情在线播放| 亚洲精品一卡2卡三卡4卡5卡| 久久精品国产清高在天天线| 十八禁人妻一区二区| 免费在线观看日本一区| 熟女电影av网| 1024香蕉在线观看| 给我免费播放毛片高清在线观看| 人人澡人人妻人| 欧美+亚洲+日韩+国产| 俄罗斯特黄特色一大片| 成年女人毛片免费观看观看9| 欧美精品亚洲一区二区| 男女下面进入的视频免费午夜 | 精品欧美一区二区三区在线| 757午夜福利合集在线观看| 美女免费视频网站| 老鸭窝网址在线观看| 国产av一区在线观看免费| 亚洲成人免费电影在线观看| 男人舔女人下体高潮全视频| 欧美绝顶高潮抽搐喷水| 日日夜夜操网爽| 国产成人系列免费观看| 久久久久久久精品吃奶| 国产aⅴ精品一区二区三区波| 少妇粗大呻吟视频| 黑丝袜美女国产一区| 国产亚洲欧美精品永久| 久热爱精品视频在线9| 欧美黑人欧美精品刺激| 久久这里只有精品19| 天天一区二区日本电影三级| 1024香蕉在线观看| 日本一区二区免费在线视频| 国产精品亚洲美女久久久| 国产不卡一卡二| 亚洲精华国产精华精| 欧美日韩亚洲国产一区二区在线观看| 一级a爱视频在线免费观看| ponron亚洲| 人成视频在线观看免费观看| 日日爽夜夜爽网站| 亚洲欧美日韩无卡精品| 香蕉丝袜av| 特大巨黑吊av在线直播 | 一个人观看的视频www高清免费观看 | 久久久水蜜桃国产精品网| 中文字幕人妻熟女乱码| 99国产精品99久久久久| 国产精品久久久av美女十八| 久久久久九九精品影院| 欧美最黄视频在线播放免费| 日本五十路高清| cao死你这个sao货| 人人澡人人妻人| 人人妻人人澡欧美一区二区| 嫩草影院精品99| 真人一进一出gif抽搐免费| 男男h啪啪无遮挡| 亚洲精品一区av在线观看| 又大又爽又粗| 久久久久国产一级毛片高清牌| 韩国av一区二区三区四区| 美女大奶头视频| 黄色视频不卡| aaaaa片日本免费| 国语自产精品视频在线第100页| 亚洲av成人av| 国产成人欧美在线观看| 欧美日韩精品网址| 国产三级黄色录像| 桃色一区二区三区在线观看| 精品不卡国产一区二区三区| 成人免费观看视频高清| 成人18禁在线播放| 男人舔女人的私密视频| 亚洲av第一区精品v没综合| 亚洲在线自拍视频| 日本五十路高清| 欧美成人一区二区免费高清观看 | 免费高清视频大片| 国产国语露脸激情在线看| 成年版毛片免费区| 哪里可以看免费的av片| 欧美成人免费av一区二区三区| 亚洲熟女毛片儿| 成人免费观看视频高清| 亚洲av电影不卡..在线观看| 精品一区二区三区视频在线观看免费| 免费高清在线观看日韩| 国产av一区在线观看免费| ponron亚洲| 国产精品精品国产色婷婷| 久久午夜综合久久蜜桃| 人人妻人人澡欧美一区二区| 1024视频免费在线观看| 亚洲国产欧美网| 午夜a级毛片| 91国产中文字幕| 国产精品亚洲美女久久久| 成人三级黄色视频| tocl精华| 少妇熟女aⅴ在线视频| 欧美激情 高清一区二区三区| 非洲黑人性xxxx精品又粗又长| 变态另类成人亚洲欧美熟女| 亚洲av日韩精品久久久久久密| 欧美黄色淫秽网站| 亚洲欧美精品综合一区二区三区| 久久久久久国产a免费观看| 国产激情久久老熟女| 久久久久久免费高清国产稀缺| 日韩欧美免费精品| 九色国产91popny在线| 精品久久久久久,| 男人操女人黄网站| 曰老女人黄片| 亚洲第一av免费看| 久99久视频精品免费| 久久精品亚洲精品国产色婷小说| 国产精品,欧美在线| 午夜免费激情av| 久久久久国产精品人妻aⅴ院| 18禁国产床啪视频网站| 在线看三级毛片| 精品福利观看| 一个人免费在线观看的高清视频| 亚洲欧洲精品一区二区精品久久久| 97碰自拍视频| 亚洲精品久久国产高清桃花| netflix在线观看网站| 欧美在线黄色| 可以在线观看的亚洲视频| 成年版毛片免费区| 国产三级黄色录像| 国产精品 欧美亚洲| 大型黄色视频在线免费观看| 18美女黄网站色大片免费观看| 亚洲午夜理论影院| 欧美黄色片欧美黄色片| 人妻久久中文字幕网| 一进一出抽搐gif免费好疼| a级毛片在线看网站| 亚洲午夜理论影院| 欧美午夜高清在线| 在线av久久热| 丝袜在线中文字幕| 男女视频在线观看网站免费 | 黄色毛片三级朝国网站| 一区福利在线观看| 国内精品久久久久久久电影| 久久精品国产清高在天天线| 国产高清视频在线播放一区| 久久久久久久精品吃奶| 男女那种视频在线观看| 久久国产精品男人的天堂亚洲| 一本一本综合久久| 亚洲国产精品合色在线| 91av网站免费观看| 欧美一级a爱片免费观看看 | 丝袜在线中文字幕| cao死你这个sao货| 欧美日本视频| 99在线人妻在线中文字幕| 精品久久久久久成人av| 国产三级在线视频| 亚洲成人久久爱视频| 亚洲人成网站在线播放欧美日韩| 欧美日韩亚洲综合一区二区三区_| 日日爽夜夜爽网站| 久久久久久久久久黄片| 欧洲精品卡2卡3卡4卡5卡区| 精品久久久久久,| 可以在线观看的亚洲视频| 亚洲一区二区三区色噜噜| 亚洲国产欧美一区二区综合| 欧美绝顶高潮抽搐喷水| 琪琪午夜伦伦电影理论片6080| 成人18禁高潮啪啪吃奶动态图| av在线播放免费不卡| 一进一出抽搐动态| 身体一侧抽搐| 欧美zozozo另类| 韩国av一区二区三区四区| 国产精品二区激情视频| 国产久久久一区二区三区| 男女午夜视频在线观看| 国产av又大| 国产视频一区二区在线看| 久久亚洲真实| 色婷婷久久久亚洲欧美| 国内毛片毛片毛片毛片毛片| 亚洲国产日韩欧美精品在线观看 | 精品久久久久久久末码| 欧美 亚洲 国产 日韩一| 亚洲人成77777在线视频| 国产精品电影一区二区三区| 国产私拍福利视频在线观看| 色尼玛亚洲综合影院| 中文字幕人成人乱码亚洲影| 久久久精品国产亚洲av高清涩受| 中文亚洲av片在线观看爽| 男女视频在线观看网站免费 | 少妇熟女aⅴ在线视频| 极品教师在线免费播放| 看免费av毛片| 免费高清视频大片| 欧美一级a爱片免费观看看 | 久久香蕉国产精品| 中文字幕久久专区| 亚洲国产欧洲综合997久久, | 免费av毛片视频| 日韩欧美在线二视频| 亚洲片人在线观看| 色av中文字幕| 女人高潮潮喷娇喘18禁视频| 久久久精品国产亚洲av高清涩受| 999久久久国产精品视频| 真人一进一出gif抽搐免费| 在线观看www视频免费| 免费看十八禁软件| 免费在线观看视频国产中文字幕亚洲| a级毛片a级免费在线| 真人做人爱边吃奶动态| av有码第一页| 丁香六月欧美| 久久香蕉国产精品| 观看免费一级毛片| 免费电影在线观看免费观看| 最新美女视频免费是黄的| 一进一出好大好爽视频| 国产高清videossex| 一进一出好大好爽视频| 精品一区二区三区四区五区乱码| 老司机靠b影院| 后天国语完整版免费观看| 999久久久精品免费观看国产| 给我免费播放毛片高清在线观看| 亚洲 欧美 日韩 在线 免费| 国产色视频综合| 精品一区二区三区视频在线观看免费| 一本久久中文字幕| 妹子高潮喷水视频| 后天国语完整版免费观看| 日韩免费av在线播放| 别揉我奶头~嗯~啊~动态视频| 国产精品综合久久久久久久免费| 麻豆国产av国片精品| 国产高清视频在线播放一区| 麻豆成人午夜福利视频| 黄色 视频免费看| 免费在线观看黄色视频的| 91字幕亚洲| 桃红色精品国产亚洲av| 精品一区二区三区视频在线观看免费| 国产亚洲av嫩草精品影院| 亚洲一区二区三区色噜噜| 国产欧美日韩一区二区精品| 成人av一区二区三区在线看| 免费在线观看成人毛片| 久久人人精品亚洲av| 亚洲一区高清亚洲精品| 国产在线观看jvid| √禁漫天堂资源中文www| 午夜免费观看网址| 淫妇啪啪啪对白视频| 亚洲熟妇熟女久久| 啦啦啦观看免费观看视频高清| 99在线人妻在线中文字幕| 亚洲av中文字字幕乱码综合 | 国产激情欧美一区二区| 成人免费观看视频高清| 国产成+人综合+亚洲专区| 成人午夜高清在线视频 | 一级片免费观看大全| 亚洲欧美精品综合一区二区三区| www.www免费av| 国语自产精品视频在线第100页| 免费看十八禁软件| 国产一级毛片七仙女欲春2 | 午夜福利高清视频| 亚洲人成伊人成综合网2020| 久久人人精品亚洲av| 成熟少妇高潮喷水视频| 国产精品久久久久久精品电影 | 国产91精品成人一区二区三区| 亚洲人成网站高清观看| 黄色视频不卡| 一本综合久久免费| 国产亚洲精品久久久久5区| 午夜激情av网站| 又大又爽又粗| 国产高清视频在线播放一区| 国产日本99.免费观看| 美女免费视频网站| 国产精品永久免费网站| 岛国视频午夜一区免费看| 日韩大尺度精品在线看网址| 国产精品日韩av在线免费观看| 久久精品国产综合久久久| 搡老妇女老女人老熟妇| 手机成人av网站| 亚洲五月天丁香| 亚洲中文字幕一区二区三区有码在线看 | 亚洲国产精品久久男人天堂| 宅男免费午夜| 午夜免费鲁丝| 亚洲性夜色夜夜综合| 成人国产综合亚洲| 一区二区三区精品91| 男人舔女人的私密视频| 欧美中文日本在线观看视频| 一区福利在线观看| 久久热在线av| 露出奶头的视频|