污水生物处理过程中N2O的逸出控制

N2O是大气中重要的温室气体之一,控制其大气浓度的增长具有重要意义.研究表明,污水生物处理的硝化反硝化过程是N2O的重要源强之一,N2O的逸出主要发生在亚硝化过程和反硝化过程,而且逸出量受环境因素影响很大.深入了解N2O的逸出机理和外界因素的影响规律是有效控制N2()的前提和基础.     

倒置A2/O—MBR工艺处理低C/N生活污水脱氮性能研究

合肥塘西河再生水厂采用倒置A/O(缺氧/厌氧/好氧—预缺氧)—MBR工艺处理低C/N城市生活污水.研究了投加碳源前后各生化反应池中有机物及氮元素的变化规律,结果表明未投加外碳源时TN的去除率为52.3％,脱氮效果不理想.通过比较乙酸钠、甲醇和乙酸三种不同外加碳源的脱氮效果,可知乙酸钠反硝化速率最高,效果最好.当乙酸钠作外碳源,投加量为50 mgCOD/L时,TN的去除率明显提高,达到74.5％.此外,还分析了投加外碳源后整个工艺系统内COD、TN物质流动情况,结果表明,缺氧池和厌氧池是COD去除的主要单元体,好氧池对COD的去除贡献增强,体系中的TN去除总量在投加外碳源后有了明显的增加,较未投加外碳源时增加了26.5％.     

Control of C/N ratio for butyric acid production from textile wastewater sludge by anaerobic digestion

Increasing textile wastewaters and their biotreatment byproduct-waste activated sludge are serious pollution problems. Butyric acid production from textile wastewater sludge by anaerobic digestion at different C/N ratios was investigated. Adding starch to textile wastewater sludge with a C/N ratio of 30 increased the butyric acid concentration and percentage accounting for total volatile fatty acids (TVFAs) to 21.42 g/L and 81.5%, respectively, as compared with 21.42 g/L and 10.6% of textile wastewater sludge alone. The maximum butyric acid yield (0.45 g/g VS), conversion rate (0.74 g/g VS(digest)) and production rate (2.25 g/L d) was achieved at a C/N ratio of 30. The biological toxicity of textile wastewater sludge also significantly decreased after the anaerobic digestion. The study indicated that the anaerobic co-digestion of textile wastewater sludge and carbohydrate-rich waste with appropriate C/N ratio is possible for butyric acid production.     

Enhanced nitrogen removal using C/N load adjustment and real-time control strategy in sequencing batch reactors for swine wastewater treatment.

The laboratory-scale sequencing batch reactor (SBR) was used to study the effectiveness of an integrated strategy of real time control with C/N ratio adjustment for practical swine wastewater treatment. Swine waste was used as the external carbon source for continuous treatment in the SBR reactors. Oxidation-reduction potential and pH were used as parameters to control the continuous denitrification and nitrification process, respectively. A constant effluent quality could be obtained, despite drastic variations in the characteristics of influent wastewater. Also, a relatively complete removal of nutrients was always ensured, since the optimum quantity of the external carbon source could be provided for complete denitrification, and a flexible hydraulic retention time was achieved by the successful real-time control strategy. The average removal efficiencies of total organic carbon and nitrogen were over 94% and 95%, respectively.     

Biological nutrient removal by applying SBR technology in small wastewater treatment plants: carbon source and C/N/P ratio effects.

SBR technology is considered an alternative to conventional processes such as Phoredox, Five-stage Bardenpho, among the others for treating nutrients in wastewaters. It is especially applicable to small communities of a just few people to a population equivalent (p.e) up to 4000. In this paper, biological nutrient removal using SBR technology in a single reactor is presented. Biological nutrient removal requires a sequence of anaerobic-anoxic-aerobic phases with multiple feeding events over one cycle. This filling strategy was adapted to enhance denitrification and phosphate release, using the easily biodegradable organic matter from the wastewater. In spite of using this feeding strategy, the organic matter concentration can be insufficient. The results show that biological nutrient removal was successfully achieved by using only one reactor, working with a low organic matter concentration in the influent (C/N/P ratio of 100:12:1.8). Nevertheless, when the C/P ratio was lower than 36 g COD x g(-1) P-P04, an accumulation of phosphate was observed. After that, the system responded quickly and returned to ideal conditions (C/P ratio of 67 g COD x g(-1) P-PO4), taking only 15 days to achieve the complete nutrient removal. Furthermore, the operational conditions and the synthetic wastewater used conferred a selective advantage to polyphosphate accumulating organisms (PAOs) over glycogen accumulating non-poly-P organisms (GAOs) as shown by the FISH analysis performed.     

Treatment of swine wastewater using MLE process and membrane bio-reactor.

The aim of this study was to develop the optimum integrated treatment system for slurry type swine wastewater through field testing. Although composting and liquid composting are the most desirable processes to treat swine wastewater, inadequate composting has been blamed as critical non-point source pollutants. In the area with limited crop land and grass land, the most feasible method to handle slurry type swine wastewater would be that the solids portion from the solids/liquid separation process is treated by composting and then the liquid portion is treated by a series of wastewater treatment processes, including physicochemical treatment system and biological nutrient removal systems such as the modified Ludzack Ettinger (MLE) process and MLE process coupled with a membrane, to satisfy the different effluent criteria. When using the appropriate solids/liquid separation system, the removal efficiency of SS, COD(Cr), and TKN was 92.4%, 73.6%, and 46.0%, respectively and the amount of bulking agent required for composting and organic loading rate for the following wastewater treatment system can be reduced by 94.8% and 84.7%, respectively. When treating the effluent from solids/liquid separation process by MLE process, the optimal volume fraction for denitrification was 20% of total reactor volume and the optimum ratio of F/M and F(N)/M were increased with increase of C/N ratio. Since the effluent quality of MLE process is not enough to discharge, the DAF process was operated with addition of FeCl3 and cationic polyelectrolyte. The effluent from the DAF process was treated in the MLE process coupled with a crossflow ultrafiltration membrane to satisfy more stringent effluent criteria. When external carbon source is added to keep 6.0 of C/N ratio, the efficiency of denitrification is best. The optimum linear velocity and transmembrane pressure for MBR process was 1.8 m/sec and 2.1 atm, respectively. By addition of external carbon source, nitrogen compounds, especially NOx-N, were considerably removed. And by addition of powdered activated carbon, the removal efficiency of COD(Cr) and COD(Mn) and the membrane flux were increased dramatically.     

碳氮比对碳氮硫同步脱除的影响

研究了不同碳氮比对碳氮硫同步脱除的影响.结果表明,C/N在0.75/1→1/1→1.26/1变化时,反应系统中碳氮硫脱除效果较好,硫化物、硝酸盐及乙酸盐去除率分别保持在92%～100%,90%～100%和100%.综合考虑碳氮硫同步脱除过程,最佳碳氮比为1/1.同时探讨了碳氯比影响碳氮硫同步脱除的机理.     

Effects of influent COD/N ratio and internal recycle ratio on nitrogen removal efficiency in the KNR process.

In this study, with the KNR process that has many advantages, the nitrogen removal efficiency of KNR was experimentally investigated at various COD/N ratios of influent conditions. The optimal operating condition of internal recycle ratio was evaluated. The TN removal efficiencies were 59.1, 72.5 and 75.9% at the COD/N ratios of 3, 5 and 7, respectively. These high removal efficiencies resulted from high denitrification rate in UMBR with high microorganism concentration. Furthermore, specific endogenous denitrification at MLVSS of 10.3 g/L that is similar to MLVSS in UMBR was over two times higher than that at MLVSS of 2.06 g/L. This result suggests that endogenous denitrification rate in UMBR is so high that the requirement of an external carbon source can be saved. As the internal recycle ratio increased from 100 to 400%, the TN removal efficiency also improved from 69.5 to 82.9%, and the optimal internal recycle ratio was 300%.     

碳源不足的城市污水Highsludge(R)高浓度活性污泥法研究

Highsludge高浓度活性污泥工艺采用兼氧-好氧组合流程,最显著的特点是活性污泥浓度高和好氧段溶解氧低.对该工艺处理碳源不足的城市污水进行了中试研究,结果表明:High-sludge高浓度活性污泥工艺可以在进水碳源不足的条件下,保证很好的TN去除效果,在进水TN不高于59.2 mg/L的条件下,出水TN低于15 mg/L,满足<城镇污水处理厂污染物排放标准>(GB18918-2002)一级A标准.试验分析了TN去除情况与各工艺运行参数的相关关系,发现MLSS和DO是控制出水TN最关键的参数.同时试验发现,高浓度活性污泥条件下,普通沉淀池可以正常运行,剩余污泥产量较少但会产生较多的生物泡沫.     

CASS工艺处理高氨氮污水的脱氮设计

重点介绍了改进的CASS工艺处理高氨氮污水的脱氮设计和运行参数,如C/N、回流比、DO、曝气时间和控制方式等的变化对脱氮效果的影响,并在此基础上给出了各参数的设计计算方法。随后的试验研究表明,改进的CASS工艺克服了传统设计的不足,在有效去除水中有机物的同时,脱氮效果良好。     

Symbiotic algal bacterial wastewater treatment: effect of food to microorganism ratio and hydraulic retention time on the process performance.

Algal incorporation into the biomass is important in an innovative wastewater treatment that exploits the symbiosis between bacterial activated sludge and microalgae (Chlorella vulgaris sp. Hamburg). It allows a good and easy algae separation by means of clarification. The effect of process parameters food to microorganisms ratio (F/M) and hydraulic retention time (HRT) on the process performance, evaluated by settleability, microalgae incorporation to biomass and nutrient removal, was studied. HRT hinted at a significant influence in the growth rate of algae, while F/M turned out to be important for stability when algae are incorporated into the biomass. This parameter also affects the total nitrogen removal of the treatment. Stable flocs with incorporated algae and supernatants with low free swimming algae concentrations were obtained at high HRT and low F/M values.     

内循环A/O—MBR处理含油废水的研究

研究了在原有A/O—MBR处理含油废水的设备中加设内循环装置后,系统对废水的处理效果,系统中微生物的变化情况以及系统膜通量的变化。研究结果表明,设置内循环装置后,中空纤维超滤膜(孔径为0.45μm)生物反应器对NH3—N、油、CODCr和TOC的去除具有较为明显的改善,同时反应器中MLSS和污泥颗粒粒径变化明显。NH3—N去除率由原来的70%上升至85%左右;对油的去除效率最高可达99%。系统的膜通量在内循环装置中趋于稳定,一周后达到29.32L/(m2.h),并在一定程度上延缓了膜污染。在MLSS为6000～8000mg/L时,系统的处理效果较好,污泥平均颗粒粒径较大,膜污染的程度较轻。因此,设置内循环装置后,大大提高了系统的处理效果,保证了出水水质。     

Odour emission inventory of German wastewater treatment plants--odour flow rates and odour emission capacity.

Wastewater Treatment plants can cause odour emissions that may lead to significant odour annoyance in their vicinity. Thus, over the past 20 years, several measurements were taken of the odour emissions that occur at WWTPs of different sizes, treatment technology, plant design and under different operating conditions. The specific aspects of odour sampling and measurement have to be considered. I presented some of the results of my odour emission measurements 11 years ago. However, it is now necessary to update the figures by evaluating newer measurement results obtained from measurements taken from 1994 to 2003. These are presented in this paper. Also, the paper highlights the odour emission capacity (OEC) measurement technique which characterises liquids and can be used to assess the results achieved by different types of treatment in the liquid phase, e.g. in a sewerage system. In addition, the OEC is a suitable parameter to set standards for the odorant content of industrial wastewaters that are discharged into the publicly owned sewerage system.     

Sensor fault diagnosis in a wastewater treatment process.

There are many sensors in a wastewater treatment process (WWTP) plant for monitoring process performance and condition. Sensor validation is essential to the success of process monitoring. In this paper, various sensor faults which can occur in WWTP are identified for taking proper remedial action at an early time. A proposed sensor fault isolation method is based on the variable reconstruction using principal component analysis (PCA). Even though several methods have been developed to identify sensor faults, they are only applicable to a static process. In other words, they cannot be successfully used to monitor severe dynamic processes such as WWTPs. We have removed this limitation by developing reconstruction methods based on a dynamic version of PCA. Artificial scenarios of sensor faults generated from the simulation benchmark have been used to validate the proposed sensor identifying methodology. Also, it is compared to a previous method to show its relative superiority in sensor fault validation in the WWTP.     

淀粉废水处理工艺改造工程实例

针对原有UASB—SBR工艺效率低、系统运行不稳定、出水含泥量高等问题,进行工艺改造,在UASB与SBR之间增设曝气沉淀池,去除SS和H2S等,有效提高SBR处理效率,并在SBR出水增设高效气浮装置,使系统保持稳定运行。实践证明,处理后出水质可达《污水综合排放标准》(GB8978—1996)一级标准。     

燃煤电厂废水综合治理近零排放解决方案探讨

对某燃煤电厂实现废水近零排放目标存在的主要问题进行了分析,对废水来水与回用水不平衡问题提出了综合治理解决方案.提出采用部分辅机冷却水回流来解决辅机冷却用水量与全厂补水量的不平衡问题并进行了可行性论证;综合治理方案实施后电厂单位发电用水量将降低19％,针对该厂末端高盐废水蒸干系统存在的问题,结合目前国内外几种主要高盐废水...     

Effect of organic loading rate on a wastewater treatment process combining moving bed biofilm and membrane reactors.

The effect of moving bed biofilm reactor (MBBR) loading rate on membrane fouling rate was studied in two parallel units combining MBBR and membrane reactor. Hollow fiber membranes with molecular weight cut-off of 30 kD were used. The HRTs of the MBBRs varied from 45 min to 4 h and the COD loading rates ranged from 4.1 to 26.6 g COD m(-2) d(-1). The trans-membrane pressure (TMP) was very sensitive to fluxes for the used membranes and the experiments were carried out at relatively low fluxes (3.3-5.6 l m(-2) h(-1)). Beside the test with the highest flux, there were no consistent differences in fouling rate between the low- and high-rate reactors. Also, the removal efficiencies were quite similar in both systems. The average COD removal efficiencies in the total process were 87% at 3-4 h HRT and 83% at 0.75-1 h HRT. At high loading rates, there was a shift in particle size distribution towards smaller particles in the MBBR effluents. However, 79-81% of the COD was in particles that were separated by membranes, explaining the relatively small differences in the removal efficiencies at different loading rates. The COD fractionation also indicated that the choice of membrane pore size within the range of 30 kD to 0.1 microm has very small effect on the COD removal in the MBBR/membrane process, especially with low-rate MBBRs.     

The removal of residual organic matter from biologically treated swine wastewater using membrane bioreactor process with powdered activated carbon.

The objective of this study was to characterize the mechanisms of the COD removal in the membrane bioreactor (MBR) process with powdered activated carbon (PAC) addition and to determine its optimal operation, for the removal of residual organic matters (ROM) from biologically treated swine wastewater. The MBR process with PAC showed higher removal efficiency of chemical oxygen demand (COD(Mn)) than that without PAC. When the average COD(Mn) concentration of the influent was 217 mg/L, the average COD(Mn) concentration of the permeate from the MBR with PAC was about 41.5 mg/L, indicating an approximate removal efficiency of 81%. On the other hand, the average COD(Mn) concentration of the permeate from the MBR without PAC was 172 mg/L. The PAC dosage estimated to obtain the above removal efficiency was about 0.74 g per litre of influent. Among the total residual organics removed by PAC-added MBR, 46.5% was removed by PAC adsorption, 20.8% by biodegradation, 4.4% by membrane separation, and 9.3% by enhanced microorganism activity. From these results, the MBR process with PAC was considered as a very useful treatment process for the reduction of COD(Mn) in biologically treated swine wastewater.     

MBR处理聚乙烯醇废水的试验研究

理论分析和试验结果表明 :采用一体式好氧膜生物反应器 (MBR)处理难降解聚乙烯醇有机废水 ,在 pH为 7～ 8,温度为 15～ 2 9℃ ,HRT为 10～ 2 0h ,SRT为 10 0d ,进水COD为 10 0～ 6 0 0mg/L的条件下 ,系统出水COD在 4 0mg/L以下 ,平均为 15 5mg/L ,COD的平均去除率为 90 7%。采用好氧MBR能有效地处理难降解聚乙烯醇有机废水     

改良A2/O工艺在污水处理厂中的应用

设计规模为20万m3/d的污水处理厂采用多点进水的改良A2/O工艺,通过对该厂各处理单元的介绍及运行分析,表明该厂工艺设计较合理,在运行中根据具体实际情况采取有效的应对措施,取得了较好的运行效果,出水水质达到设计要求,而且生物除磷效果好.