BAC滤池对浊度和颗粒数的控制研究

传统的贾第鞭毛虫和隐孢子虫（简称“两虫”）检测方法存在诸多不足，为此选用浊度和颗粒数作为“两虫”的替代指标，以对浊度和颗粒物的去除率来衡量生物活性炭（BAC）滤池对“两虫”的控制效果。试验结果表明：采用颗粒数表征滤后水水质比采用浊度更适宜。过滤初期颗粒数从峰值降到50个／mL以下所需的时间比浊度降到0．1NTU所需的时间多1h左右。正常过滤期间BAC滤池进水浊度一般在0．1NTU以下，经过BAC滤池处理后，浊度得到进一步降低，平均去除率为52．7％。炭层对浊度的去除率为56．4％，其出水浊度基本上都低于0．05NTU，而砂层对浊度不但没有去除能力，反而使出水浊度平均上升了约3．7％。炭层对颗粒物的平均去除率为33．3％，砂层对颗粒物的平均去除率为8．5％。     

臭氧/过滤/活性炭工艺深度处理污水厂二级出水

采用臭氧/过滤/活性炭工艺深度处理济南市水质净化二厂的二级出水.结果表明,在臭氧投加量为3 mg/L、滤床和炭床的滤速均为6～12 m/h、各工艺段的接触时间为13 min的务件下,组合工艺对浊度、CODMn、NH4+-N和NO2--N均有一定的去除效果,而对NO3--N基本无去除作用;当原水的平均浊度、CODMn、NH4+-N和NO2--N分别为0.87 NTU、1.24 mg/L、1.78 mg/L、0.13 mg/L时,组合工艺出水的平均浊度、CODMn、NH4+-N和NO2--N分别可降至0.25 NTU、0.79mg/L、1.29 mg/L、0.05 mg/L.     

水力停留时间对BAF除污性能的影响

研究了水力停留时间(HRT)对曝气生物滤池(BAF)除污效果的影响。结果表明:HRT对BAF处理效果的影响较大,当HRT为0.63 h时,出水浊度、COD、氨氮和总氮浓度均较高,BAF的除污效果较差;当HRT为0.83 h时,出水COD浓度可降至50 mg/L以下,去除率可达到85.87%;当HRT为1.0 h时,BAF对浊度、氨氮和总氮均有较好的去除效果,去除率分别为95.98%7、7.08%4、0.09%,出水浊度<4 NTU、氨氮<8 mg/L、总氮<35 mg/L。     

Purification capacity of a highly loaded laboratory scale tidal flow reed bed system with effluent recirculation

The purification capacity of a laboratory scale tidal flow reed bed system with final effluent recirculation at a ratio of 1:1 was investigated in this study. In particular, the four-stage reed bed system was heavily loaded with strong agricultural wastewater. Under the hydraulic and organic loading rates of 0.43 m3/m2.d and 1055 gCOD/m2.d, respectively, the average removal efficiencies obtained for COD, BOD5, SS, NH4-N and P were 77%, 78%, 66%, 62% and 38%, respectively. Even with the high loading rates, approximately 30% of NH4-N was converted into NO2-N and NO3-N from the mid-stage of the system where nitrification took place. The results suggest that the multi-stage reed bed system could be employed to treat strong wastewater under high loading, especially for the substantive mass removal of solids, organic matter and ammoniacal-nitrogen. Tidal flow combined with effluent recirculation is a favourable operation strategy to achieve this objective.     

Backwashing and conditioning of a deep bed filter

The traditional conceptual model explaining the initial effluent degradation as a result of the backwashing, is proved to be insufficient.Mathematically and experimentally it is demonstrated that the initial effluent degradation is 95% due to an inadequate pore structure of the filter bed. An increased coagulant dose at the start of the filtration or a preconditioning of the filter bed during the last minutes of the backwashing operation, can reduce the initial turbidity peak. Such a treatment has also consequences for the complete filter run.     

Characteristics of particle removals in a compressible media filter system

The ability to adjust the properties of the filter medium by altering the degree of the medium compression is important because the different porosities in media affect the ideal filter performance according to the properties of influent wastewater. This study therefore focused on the particle size distribution (PSD) of compressible media filter (CMF) effluents depending on the compression ratio (0–30%) and the filter bed depth (Layers 1–5) in order to evaluate the CMF performance. The results showed that the removal efficiency for particles larger than 10 µm was more than 90% while that for particles smaller than 10 µm was less than 85% of removal efficiency. From the power law fit, substantial decreases in the number of large‐sized particles were observed in the PSD. Particle removal efficiencies increased along with the average compression ratio increase. Furthermore, the results demonstrated that each layer in the bed had a different role in the filter performance, and it was found that a filter bed of about 0.45–0.60 m would be needed for the production of the desired effluent quality in this study. The detachment phenomenon was observed in particles larger than 5 µm, especially in 5–15 µm particles.     

某再生水厂混凝/沉淀/过滤工艺的处理效果评估

某再生水厂的供水能力为10×104m3/d,采用混凝、沉淀、过滤工艺,原水为城市污水厂的二级处理出水.结合实际运行数据,分析了该工艺及其各单元对几种主要指标的去除效果.监测结果显示,该工艺对COD、SS、TP具有较好的去除效果,但对TN、BOD5的去除率较低,对此可在前端增加曝气生物滤池等单元加以解决.该研究对于污水再生处理工艺的选择具有指导意义.     

化学混凝对两级曝气生物滤池出水的除磷效果研究

为解决两级曝气生物滤池处理城市污水时除磷效果欠佳的问题，采用化学混凝工艺对其出水进行处理，以聚合硫酸铁（PFS）为絮凝剂，通过烧杯试验考察了PFS投量及助凝剂聚丙烯酰胺（PAM）对除磷效果的影响，并通过中试考察了混凝、沉淀、过滤工艺的除磷效果。结果表明，PAM的助凝作用并不明显，单独投加130mg／L的PFS即可使出水TP〈1mg／L。在生物处理单元稳定运行的情况下，中试工艺的PFS投量在90-95mg／L时可使出水TP〈1mg／L，总铁〈0．5mg／L。     

强化活性炭滤池过滤性能的试验研究

采用在活性炭滤池前端投加不同药剂的方法深度净化某水厂沉淀池出水,考察了不同滤池形式、聚合氯化铝(PAC)投加量和阳离子型聚丙烯酰胺(PAM)投加量对沉后水浊度的去除效果。结果表明,在下向流滤池前端投加0.3 mg/L的PAC和0.03 mg/L的PAM可以明显强化活性炭滤池的过滤效果,使出水浊度小于0.1 NTU;与砂滤池出水相比,活性炭滤池对浊度的去除率提高了16.6%,CODMn去除率提高了56%;相应的滤池水头损失增加较快,但仍可以满足运行周期不小于24 h的设计要求;滤后水中铝和溴酸盐含量均满足《生活饮用水卫生标准》(GB 5749—2006)要求。     

前置反硝化BAF工艺处理景观水体

为了提高曝气生物滤池(BAF)对景观水体的脱氮效果,开发了前置反硝化BAF工艺,考察了其对景观水体的处理效果及影响因素,并与传统BAF工艺作比较。结果表明,前置反硝化BAF工艺对TN和浊度的去除效果明显优于传统BAF工艺,前者对TN和浊度的平均去除率分别为45%和88%,而后者的分别为30%和47%;两种工艺对COD和氨氮的去除效果相近,但前置反硝化BAF工艺的出水水质更稳定;对于前置反硝化BAF工艺,当水力负荷为1.42~4.95 m/h时,对COD、氨氮和TN的去除率均随水力负荷的增加而降低;在水力负荷为2.12 m/h的条件下,回流比对COD和氨氮的去除效果影响不大,但对TN的去除率随回流比的增加呈先升高后降低的趋势,最佳回流比为1.5∶1;另外,对TN的去除率随进水C/N值的增加而升高,当C/N6时,系统的脱氮效果较好。     

Occurrence and removal of estrogens and beta blockers by various processes in wastewater treatment plants

This study aims at evaluating occurrence and treatment efficiency of five estrogenic hormones and ten beta blockers in wastewater treatment plants (WWTP). The use of consistent sampling procedures, analytical techniques and data processing enabled to achieve an accurate comparison of the performances of the different treatment processes. First, the occurrence of molecules was evaluated in fourteen rural and urban WWTP located in France. Free and total estrogens were analyzed showing that more than 84% of estrogens in the dissolved phase of influent samples are in the free form. In effluent samples, comparable mean values but higher variation are underlined (RSD from 13 to 54% depending on the estrogen, compared to 11-21% for influents). Most of the target molecules are quantified in 30 influent and 31 effluent samples. Similar occurrence frequencies are obtained for influents from rural (6 WWTP) and urban areas (8 WWTP), except for betaxolol which is only quantified in urban wastewaters. Removal efficiencies of 8 biological treatments were studied: suspended growth biomass (activated sludge) and attached growth systems (biofilter, rotating biological contactor, reed-bed filter, trickling filter). Biological treatments are efficient to remove estrogens from the dissolved phase, with removal rate around 90%. For beta blockers, acebutolol and nadolol are efficiently removed (mean removal rate of 80%), whereas sotalol and propranolol are hardly impacted by biological treatments (removal rate below 20%). Finally, 9 tertiary treatment processes were evaluated. Ozonation, reverse osmosis and activated carbon filtration prove a high removal efficiency for beta blockers (above 80%). On the contrary, high speed chemical settler, sand filtration, silex filtration, microfiltration and UV present generally removal rates below 30% for all beta blockers. The polishing pond studied presents variable removal performances depending on the molecules (up to 75% for propranolol). The role of the hydraulic retention time on the removal efficiencies is confirmed.     

Pilot-scale investigation on the removal of organic foulants in secondary effluent by slow sand filtration prior to ultrafiltration

Natural biofiltration processes have been verified as effective pre-treatment choice improving the performance of low-pressure membranes (MF/UF) in wastewater reclamation. In the present work, pilot-scale slow sand filtration (SSF) was used to simulate bank filtration at high filtration rates (from 0.25 m/h to 0.5 m/h) to filter secondary effluent prior to UF. The results showed that SSF improved the performance of UF to a large extent. Related to previous work biopolymers are considered as major dissolved organic foulants in treated wastewater. The removal of these organic foulants in slow sand filters and factors affecting the performance of SSF were investigated. It was observed that the removal of biopolymers took place mainly at the upper sand layer and was related to biological degradation. Tests on the degradability of biopolymers verified that they are biodegradable. Sixteen months monitoring of biopolymer concentration in the secondary effluent indicated that it varied seasonally. In winter season the concentration was much higher than during the summer months. Higher temperature and lower biopolymer concentration led to more effective foulants removal and more sustainable operation of SSF. During the whole experimental period, the performance of SSF was always better at filtration rate of 0.25 m/h than at 0.5 m/h. Under the present experimental conditions, SSF exhibited stable and effective biopolymer removal at temperatures higher than 15 °C, at biopolymer concentrations lower than 0.5 mg C/L and with sufficient oxygen available.     

Nitrate removal characteristics of high performance fluidized-bed biofilm reactors

Two laboratory-scale high performance fluidized bed biofilm reactors (FBBR) with sand as the biofilm carrier were used to investigate the denitrification of high-strength nitrate wastewater with specific emphasis on the effect the nitrogen loading rate and the superficial velocity (V(s)). The results demonstrated that the FBBR system is capable of efficiently handling an exceptionally high nitrate nitrogen concentration of 1000 mg N/L. At a loading rate of 6.3 kg-N/m(3)(bed).d almost complete denitrification was achieved with a removal efficiency of 99.8% and an effluent concentration of 2mg N/L at V(s) values of 45, 55 and 65 m/h. The maximum efficient loading rate (R(max)) at which the US drinking water nitrate-nitrogen standard concentration of 10mg N/L would be exceeded was found to be a function of the applied V(s). The R(max) was found to be 12 kg-N/m(3)(bed).d at a V(s) value of 45 m/h. As V(s) was increased to 55 and 65 m/h, the optimum R(max) dropped to 9.5 and 8 kg-N/m(3)(bed).d, respectively. Higher denitrification rates were achieved at relatively lower V(s). However, there is a minimum practical velocity below which agglomeration of biomass would occur. The suspended solids concentration in the effluent was below 30 mg/L throughout the study.     

气液混合泵气浮系统处理低浓度二级出水的研究

气浮-过滤是一种经济有效的污水深度处理工艺。通过小试研究了气浮单元对低浓度二级出水（COD〈60mg／L）的处理效果,并以COD、TP和浊度为去除对象,考察了絮凝剂种类、溶气压力和回流比对处理效果的影响。结果表明,对于低浓度的二级出水,采用气液混合泵的气浮单元可将COD、TP和浊度分别降低到20mg／L、0．5mg／L和0．5NTU;聚合氯化铝（PAC）对COD和浊度的去除效果要好于聚合硫酸铁（PFS）,而PFS对磷的去除率要高于PAC;适宜的工作参数为：PFS的授加量为50mg／L,PAC的授加量为30mg／L,溶气压力为343～441kPa,回流比为30％～50％。     

生物催化滤池处理高氨氮水源水

针对生物滤池处理高氨氮水源水过程中硝酸盐、亚硝酸盐积累的问题,提出一种能够同时去除"三氮"污染物的强化过滤技术——生物催化滤池。该技术将传统生物过滤与催化还原反应相结合,在生物过滤去除氨氮的同时,钯/锡双金属催化滤料可将硝酸盐氮和亚硝酸盐氮还原为氮气。在滤池的滤速为10 m/h时,对氨氮和TOC的去除率分别为82. 12%和71. 94%,主要依靠生物滤层内微生物的降解作用来去除;对硝酸盐氮和亚硝酸盐氮的去除率分别为58. 22%和78. 65%,主要通过催化还原滤料的化学反应来去除;滤池出水浊度<3 NTU。生物催化滤池在生化反应和催化还原的共同作用下能够有效缓冲低温、高氨氮、高硝酸盐氮、高亚硝酸盐氮以及高TOC等特殊条件下短时间连续冲击,具有较强的抗冲击负荷能力,保证产水水质稳定。生物催化滤池可以作为微污染水源水的预处理工艺,保障后续工艺的稳定运行,具有良好的应用前景。     

深床直接过滤工艺深度处理城市污水

采用深床直接过滤工艺对城市污水处理厂的二级出水进行了深度处理，考察了同考脱氮除磷的可行性和运行条件。研究表明，通过铁盐絮凝剂的加入，借助微絮凝直接过小可有效去除水中的PO^3-4－P（去除率＞90％）；通过在滤池前加入甲醇作为外碳源，在滤池中进行同步脱氮，气水联合反冲洗相的冲洗方式可使过滤周期长达40h左右。     

Chitosan and metal salt coagulant impacts on Cryptosporidium and microsphere removal by filtration

Maintenance of appropriate chemical pretreatment is a critical component of ensuring proper filtration performance. Pilot-scale in-line filtration studies were performed to investigate the relative impacts of chitosan, alum, and FeCl₃ coagulation on the removal of Cryptosporidium parvum oocysts and oocyst-sized polystyrene microspheres by granular media filtration. Similar removals of oocysts and microspheres were achieved when optimal coagulant doses were utilized. Sub-optimal alum and FeCl₃ coagulation resulted in a deterioration filter effluent turbidity (0.2-0.3 NTU) and total particle counts (30-100 total particles ≥2 μm/mL) that were accompanied by reduced (by ∼2-3-log) median oocyst and microsphere removals by filtration. At all doses investigated, chitosan coagulation resulted in excellent turbidity and particle reductions by filtration. Nonetheless, chitosan coagulation at doses of 0.1, 0.5, and 1.0 mg/L did not result in appreciable improvements in C. parvum oocyst removal relative to complete coagulation failure (median oocyst removals were <∼1-log). As well, oocyst-sized polystyrene microspheres appear to be reasonable indicators of C. parvum oocyst removal by in-line filtration preceded by alum and FeCl₃ coagulation, but not chitosan coagulation.     

甲醇为碳源时生物滤池去除二级出水中氮、磷的研究

以甲醇为碳源，进行了生物滤池去除二级处理出水中氮、磷的试验研究。结果表明，随着甲醇投量的增大则生物滤池出水中的总氮浓度降低，但对总磷的去除率呈下降趋势。当甲醇投量为10mg／L时，生物滤池出水中的总氮〈6．60mg／L，对总氮的去除率〉37％，对总磷的去除率〉43％；当甲醇投量为20mg／L时，生物滤池出水中的总氮〈1．20mg／L，对总氮的去除率〉88％，对总磷的去除率〉9％；当甲醇投量为30mg／L时，生物滤池出水中的总氮〈1．20mg／L，对总氮的去除率〉88％，对总磷的去除率〉6％。当滤速在3～8．5m／h间变化时，陶粒滤池的脱氮除磷效果基本不受影响；砂滤池的脱氮除磷效果稍优于陶粒滤池。     

砾石填料床预处理沈抚灌渠污水的试验研究

采用砾石填料床预处理沈抚灌渠污水,考察其对COD、NH_3-N、浊度的去除效果.结果表明,在设计水力停留时间为3.5 h、最佳气水比为5:1的条件下,该工艺对COD、NH_3-N和浊度的去除率均达到50%以上,完全满足预处理的要求,为后续处理提供了有利条件.     

高铁矿井水回用处理工艺研究

针对韩桥矿高铁矿井水质,考察了混凝＋沉淀＋过滤回用处理工艺除铁的最佳运行条件。结果表明,以聚合氯化铝（PAC）作为混凝剂,最佳投药量为80mg／L时,铁的去除率可达到91％;选择天然锰砂作为滤料,滤速在8～10m／h,进水pH值高于6．05,滤层高度大于75cm时,锰砂除铁效果较好,出水铁含量在0．1mg／L以下,可以满足《城市污水再生利用工业回用水水质》（GB／T19923--2005）中的限值要求。