序批式生物膜法对味精废水的提标处理研究

在序批式活性污泥反应器(SBR)中加入不同类型的填料而形成序批式生物膜反应器(SBBR),并进行平行比选试验,考察通过投加生物填料对河南某味精生产企业原有SBR工艺进行升级改造的技术可行性。试验结果表明:投加了悬浮球的SBBR反应器内的生物量和微生物种类均得到了较大程度的增加。在水温为15～22℃、pH值为6.5～7.2、气水比为10∶1以及进水COD为464～601mg/L、NH4+-N为69.8～117.5mg/L、TN为77.0～129.1mg/L的条件下,该反应器对COD、NH4+-N、TN的平均去除率分别为90.3%、81.8%、59.7%,平均出水浓度分别为53、16.8、42.3mg/L,出水水质得到了显著的改善。     

序批式生物膜反应器处理屠宰废水

屠宰废水首先经过栅网去除粗大颗粒状悬浮物并静沉除油,然后经序批式生物膜反应器（ＳＢＢＲ）处理进一步去除有机物,最后过滤去除色主和微细悬浮固体。结果表明,各污染指标的去除率ＣＯＤｃｒ为９７％,ＢＯＤ５为９９％,ＴＫＮ为９２％,油脂为８２％,最后出水水质满足国家二级排放标准。     

序批式生物膜反应器的生物膜特性研究

通过扫描电镜对具有除磷功能的序批式生物膜反应器中生物膜的形态结构进行了观察，并考察了容积负荷、曝气量和厌氧循环水量对生物膜量的影响。结果发现，生物膜主要由微生物及其胞外多聚物组成，大量的微生物及其胞外多聚物相互连结，形成稳定的缠结结构。平均每片填料上附着的生物膜质量为4．088g，挥发性生物膜质量与生物膜干质量的比值为0．861，表明活性生物量较高。填料上的生物膜量主要受曝气量和厌氧循环水量的影响，而容积负荷对填料上的生物膜量基本没有影响。     

序批式移动床生物膜反应器处理低温污水研究

采用序批式移动床生物膜反应器(SBMBBR)处理低温污水,研究了不同负荷条件下的除污效果,并与传统SBR反应器进行对比.试验中采用人工模拟生活污水,水温为(10±1)℃,反应器的COD负荷分别为3.4、2.2、1.3 kg/(m3·d).结果表明,在这3种负荷下SBMBBR均可达到较好的COD去除效果;对TP的去除率均超过90％,且处理效果稳定,厌氧阶段的释磷量是传统SBR的2倍.较高的有机负荷有利于除磷,但不利于脱氮.与传统SBR相比,SBMBBR表现出更好的脱氮效果,对TN的去除率在研究的负荷范围内均超过了80％.     

多级悬浮填料生物反应器处理石化废水

采用多级悬浮填料生物反应器处理石化废水，在填料投加率为50％、水力停留时间为8h的工况条件下，当进水BOD5为108－234mg/L,CODcr为253．4－444．6mg/L,NH3-N为20．8－26．2mg/L时，二级反应器对其平均去除率分别为90．7％、74％和53．2％；三级反应器对其平均去除率分别为93．7％、77．7％和84．6％，这说明采用多级反应器在保证有效去除BOD、COD等有机污染物的同时，可以大大提高对NH3－N的去除效果。     

催化铁内电解/生物膜法处理化工废水

化工废水因含有难降解和对生物有抑制性的物质而较难处理，为此以某工业区的化工废水为研究对象，考察了催化铁内电解／悬浮填料生物膜法的处理效果，并同现有工艺进行比较。结果表明，催化铁内电解可提高废水的可生化性，整个工艺对COD、BOD5、NH3-N、色度等的去除效果较现有工艺有明显改善。     

序批式生物膜/颗粒污泥工艺的同步脱氮除磷效果

针对我国现行污水处理工艺不能在同一个构筑物内实现同步脱氮除磷,特别是能耗高、效率低、占地面积大的现状,将活性污泥和生物膜法相结合,自行设计了一套序批式生物膜/颗粒污泥工艺试验装置,并考察了同步脱氮除磷效果。运行表明,该工艺具有良好的除污效果,当进水COD、NH4+-N、TN、PO34--P的平均浓度分别为302、30.66、32.84、10.45 mg/L时,出水平均浓度分别为25.81、5.91、9.64、2.40 mg/L,平均去除率分别为91.44%、80.69%、70.61%、77.00%;该工艺具有良好的反硝化除磷效果,每消耗1 mg的NO3--N可以去除1.04 mg的PO34--P。     

折流曝气生物滤池除磷效能的研究

针对城市污水处理中曝气生物滤池容易堵塞,除磷效果不好等问题,对折流曝气生物滤池(BBAF)的运行条件,除磷效能进行了研究;为提高其除磷效果,研究适于BBAF反应器的除磷方法,对其除磷机理进行了深入研究。     

处理屠宰废水的一种新方法──序批式生物膜法

采取对比研究的方法,在相同条件下考察序批式生物膜法和序批式活性污泥法对屠宰废水的处理效果。通过对试验结果的分析表明,与序批式活性污泥法相比,序批式生物膜法不仅可以克服序批式活性污泥法的弊端,而且其处理效果更好、运行管理更为方便,是一种优化处理屠宰废水的新方法,具有广阔的应用前景。     

压力式生物膜反应器处理榨菜腌制废水的效能

通过对加压、射流曝气及生物膜技术的优化集成,开发出一种压力式生物膜反应器,并考察了有机负荷、压力和供气量对该反应器处理榨菜腌制废水效能的影响。结果表明:在水温为(30±5)℃、压力为0.2 MPa、有机负荷为16 kgCOD/(m3.d)、磷负荷为160 gPO43--P/(m3.d)、DO为5 mg/L、供气量为300 L/h及不排泥的条件下,反应器对溶解性有机物和磷的去除率分别为94.6%和54.3%,与常压处理工艺相比,对有机物的去除效能提高了约25倍,其除磷途径为磷酸盐生物还原。生物膜反应器适宜的压力为0.14 MPa,供气量宜为300 L/h。     

Anoxic treatment of phenolic wastewater in sequencing batch reactor

Studies were conducted on the anoxic phenol removal using granular denitrifying sludge in sequencing batch reactor at different cycle lengths and influent phenol concentrations. Results showed that removal exceeded 80% up to an influent phenol concentration of 1050 mg/l at 6 h cycle length, which corresponded to 6.4 kg COD/m3/d. Beyond this, there was a steep decrease in phenol and COD removal efficiencies. This was accompanied by an increase in nitrite concentration in the effluent. On an average, 1 g nitrate-N was consumed per 3.4 g phenol COD removal. Fraction of COD available for sludge growth was calculated to be 11%.     

Treatment of easily degradable wastewater in a stirred anaerobic sequencing batch biofilm reactor

The main objectives of this study were to evaluate the performance of an anaerobic sequencing batch reactor when subjected to a progressive increase of influent glucose concentration and to estimate the kinetic parameters of glucose degradation. The reactor was initially operated in 8-h cycles, treating glucose in concentrations of 500, 1000 and 2000 mg l(-1). No glucose was detected in the effluent under these three conditions. The reactor showed operating stability when treating a glucose concentration of approximately 500 mg l(-1), with filtered chemical oxygen demand (COD) removal efficiencies varying from 93% to 97%. Operational instability occurred in the operation with glucose concentrations of approximately 1000 and 2000 mg l(-1), caused mainly by a production of extracellular polymeric substances (EPS), which led to hydrodynamic and mass transfer problems in the reactor. The mean volatile acid concentration values in the effluent were approximately 159+/-72 and 374+/-92 mg l(-1), respectively. A first-order model was adjusted to glucose concentration profiles and a modified model, including a residual concentration of substrate, was adjusted to COD temporal profiles. To check the formation of EPS, the reactor was operated in 3-h cycles with concentrations of 500 and 1000 mg l(-1). The purpose of this step was to discover if the production of EPS resulted from the biomass's exposure to a low concentration of substrate over a long period of time. Thus, it was hypothesized that a reduction of the time cycle would also reduce the exposure to low concentrations. However, this hypothesis could not be confirmed because large amounts of EPS were formed already under the first operational condition, using approximately 500 mg l(-1) of glucose in the influent, thus indicating the fallacy of the hypothesis. The production of EPS proved to depend on the organic volumetric load applied to the reactor.     

Influence of the agitation rate on the treatment of partially soluble wastewater in anaerobic sequencing batch biofilm reactor

This work reports on the influence of the agitation rate on the organic matter degradation in an anaerobic sequencing batch reactor, containing biomass immobilized on 3 cm cubic polyurethane matrices, stirred mechanically and fed with partially soluble soymilk substrate with mean chemical oxygen demand (COD) of 974+/-70 mg l(-1). Hydrodynamic studies informed on the homogenization time under agitagion rates from 500 to 1100 rpm provided by three propeller impellers. It occurred very quickly compared to the total cycle time. The results showed that agitation provided good mixing and improved the overall organic matter consumption rates. A modified first-order kinetic model represented adequately the data in the entire range of agitation rate. The apparent first-order kinetic constant for suspended COD rose approximately 360% when the agitation rate was changed from 500 to 900 rpm, whereas the apparent first-order kinetic constant for soluble COD did not vary significantly.     

Granulation of activated sludge in a pilot-scale sequencing batch reactor for the treatment of low-strength municipal wastewater

Aerobic granulation of activated sludge was achieved in a pilot-scale sequencing batch reactor (SBR) for the treatment of low-strength municipal wastewater (<200 mg L⁻¹ of COD, chemical oxygen demand). The volume exchange ratio and settling time of an SBR were found to be two key factors in the granulation of activated sludge grown on the low-strength municipal wastewater. After operation of 300 days, the mixed liquor suspended solids (MLSS) concentration in the SBR reached 9.5 g L⁻¹ and consisted of approximate 85% granular sludge. The average total COD removal efficiency kept at 90% and NH₄⁺-N was almost completely depleted (∼95%) after the formation of aerobic granules. The granules (with a diameter over 0.212 mm) had a diameter ranging from 0.2 to 0.8 mm and had good settling ability with a settling velocity of 18-40 m h⁻¹. Three bacterial morphologies of rod, coccus and filament coexisted in the granules. Mathematical modeling was performed to get insight into this pilot-scale granule-based reactor. The modified IWA activated sludge model No 3 (ASM3) was able to adequately describe the pilot-scale SBR dynamics during its cyclic operation.     

Coupling of sequencing batch reactor and mesh filtration: operational parameters and wastewater treatment performance

Wastewater treatment performance of the combined process of sequencing batch reactor (SBR) and mesh filtration bio-reactor was investigated with a synthetic wastewater. In this system, the filtration was performed only by the water level difference between the reactor and the effluent port, with the help of a sludge layer which accumulated on the mesh filter.

A half volume of the mixed liquor was filtrated for ca. 1 h, and the filtration time was not affected by the initial pressure within the range of 0.5–2.0 m-H₂O. Since the mesh filter could effectively reject the biomasses in the reactor, the effluents contained SS of less than 1 mg/L and BOD of less than 10 mg/L under continuous or intermittent aeration conditions. Nitrogen was also removed effectively with the adjustment of aeration time under the intermittent aeration conditions.

The results obtained in this work indicate that mesh filtration could be effectively combined with SBR and improve the performance of SBR.

In addition, it was shown that the performance of the mesh filtration such as filtration time and solids separation was influenced significantly by the saccharide content in the exocellular polymer of the activated sludge.     

Demonstration of nitrogen removal via nitrite in a sequencing batch reactor treating domestic wastewater

Nitrogen removal via nitrite, as opposed to the traditional nitrate, may be beneficial for carbon-limited biological wastewater treatment plants. However, reliable termination of nitrification at nitrite (nitritation) has proved difficult in the treatment of domestic wastewater. In this study, nitritation was attained in a sequencing batch reactor (SBR) with pre-denitrification treating domestic wastewater (total Kjeldahl nitrogen (TKN) concentration of about 43 mg NL(-1)) by aerobic duration control. The aerobic duration control strategy terminates aeration upon completion of ammonium oxidation with accumulated nitrite still remaining. The SBR was purposefully operated such that the influence of other known selection factors for nitritation was absent. The process proved effective in achieving a steady state whereby over 80% nitritation was sustained. Investigation of the cause of nitritation by a calibrated ammonium and nitrite oxidation model showed aerobic duration control as the key factor leading to nitritation.     

Biofilm growth and characteristics in an alternating pumped sequencing batch biofilm reactor (APSBBR)

A novel biofilm reactor-alternating pumped sequencing batch biofilm reactor (APSBBR)-was developed to treat synthetic dairy wastewater at a volumetric chemical oxygen demand (COD) loading rate of 487 g COD m(-3) d(-1) and an areal loading rate of 5.4 g COD m(-2) d(-1). This biofilm reactor comprised two tanks, Tanks 1 and 2, with two identical plastic biofilm modules in each tank. The maximum volume of bulk fluid in the two-tank reactor was the volume of one tank. The APSBBR was operated as a sequencing batch biofilm reactor with five operational phases-fill (25 min), anoxic (9 h), aerobic (9 h), settle (6 h) and draw (5 min). The fill, anoxic, settle and draw phases occurred in Tank 1. In the aerobic phase, the wastewater was circulated between the two tanks with centrifugal pumps and aeration was mainly achieved through oxygen absorption by micro-organisms in the biofilms when they were exposed to the air. In this paper, the biofilm growth and characteristics in the APSBBR were studied in a 98-day laboratory-scale experiment. During the course of the study, it was found that the biofilm thickness (delta) in Tank 1 ranged from 1.2 to 7.2 mm and that in Tank 2 from 0.5 to 2.2 mm; the biofilm growth against time (t) can be simulated as delta=0.07t0.99 (R2 = 0.97, P = 0.002) in Tank 1 and delta = 0.08t0.66 (R2 = 0.81, P = 0.04) in Tank 2. The biomass yield coefficient, Y, was 0.18 g volatile solids (VS) g(-1) COD removal. The biofilm density in both tanks, X, decreased as the biofilm thickness increased and can be correlated to the biofilm thickness, delta .     

High-rate anaerobic treatment of Fischer-Tropsch wastewater in a packed-bed biofilm reactor

This study investigates the anaerobic treatment of an industrial wastewater from a Fischer-Tropsch (FT) process in a continuous-flow packed-bed biofilm reactor operated under mesophilic conditions (35 °C). The considered synthetic wastewater has an overall chemical oxygen demand (COD) concentration of around 28 g/L, mainly due to alcohols. A gradual increase of the organic load rate (OLR), from 3.4 gCOD/L/d up to 20 gCOD/L/d, was adopted in order to overcome potential inhibitory effects due to long-chain alcohols (>C6). At the highest applied OLR (i.e., 20 gCOD/L/d) and a hydraulic retention time of 1.4 d, the COD removal was 96% with nearly complete conversion of the removed COD into methane. By considering a potential of 200 tCOD/d to be treated, this would correspond to a net production of electric energy of about 8 × 10⁷ kWh/year.During stable reactor operation, a COD balance and batch tests showed that about 80% of the converted COD was directly metabolized through H₂⁻ and acetate-releasing reactions, which proceeded in close syntrophic cooperation with hydrogenotrophic and acetoclastic methanogenesis (contributing to about 33% and 54% of overall methane production, respectively). Finally, energetic considerations indicated that propionic acid oxidation was the metabolic conversion step most dependent on the syntrophic partnership of hydrogenotrophic methanogens and accordingly the most susceptible to variations of the applied OLR or toxicity effects.     

Nitrogen dynamics and removal in a horizontal flow biofilm reactor for wastewater treatment

A horizontal flow biofilm reactor (HFBR) designed for the treatment of synthetic wastewater (SWW) was studied to examine the spatial distribution and dynamics of nitrogen transformation processes. Detailed analyses of bulk water and biomass samples, giving substrate and proportions of ammonia oxidising bacteria (AOB) and nitrite oxidising bacteria (NOB) gradients in the HFBR, were carried out using chemical analyses, sensor rate measurements and molecular techniques. Based on these results, proposals for the design of HFBR systems are presented.The HFBR comprised a stack of 60 polystyrene sheets with 10-mm deep frustums. SWW was intermittently dosed at two points, Sheets 1 and 38, in a 2 to 1 volume ratio respectively. Removals of 85.7% COD, 97.4% 5-day biochemical oxygen demand (BOD₅) and 61.7% TN were recorded during the study.In the nitrification zones of the HFBR, which were separated by a step-feed zone, little variation in nitrification activity was found, despite decreasing in situ ammonia concentrations. The results further indicate significant simultaneous nitrification and denitrification (SND) activity in the nitrifying zones of the HFBR. Sensor measurements showed a linear increase in potential nitrification rates at temperatures between 7 and 16 °C, and similar rates of nitrification were measured at concentrations between 1 and 20 mg NH₄-N/l. These results can be used to optimise HFBR reactor design. The HFBR technology could provide an alternative, low maintenance, economically efficient system for carbon and nitrogen removal for low flow wastewater discharges.     

Aerobic granulation with industrial wastewater in sequencing batch reactors

Granular sludge formation was promoted in two laboratory scale sequencing batch reactors (SBRs), R1 and R2 fed with industrial wastewater produced in a laboratory for analysis of dairy products. Both reactors were operated under similar conditions during most of the experimental period. However, an anoxic phase between 10 and 30 min was included at the beginning of every cycle of operation of R1, but not in R2. Organic and nitrogen loading rates applied to both systems were high, up to 7 g COD/(L d) and 0.7 g N/(L d). Nitrogen removal efficiency was 70% in both units even considering that R2 was operated always under aerobic conditions. Granules with similar morphology were developed in both systems. Size distribution was comprehended between 0.25 and 4.0 mm for both systems. The presence of TSS in the effluent of the SBRs was strongly affected by either the length of the withdrawal period or by the particulated COD to biomass ratio (CODp/VSS) applied to the systems. The lower concentrations of TSS in the effluent were attained when the systems were operated with a CODp/VSS ratio lower than 0.12 g COD/g VSS. There was a strong reduction of the average TSS content in the effluent from 450 to 200 and 150 mg TSS/L when the length of the withdrawal period was diminished sequentially from 3 to 1 and 0.5 min, respectively. This was caused by a more intensive washout of small suspended biomass aggregates that took place when the length of this period was shortened.