物化生化联合工艺处理难降解有机化工废水

利用CS药剂—铁炭还原—水解酸化—SBR组合工艺处理难降解有机化工废水,并对试验现象和结果进行了分析。试验结果表明,组合工艺最优参数为CS试剂投加200mg/L,铁炭还原铁粉及炭粉质量比1∶1,水解酸化池HRT9h,SBR工艺采用非限制性曝气的运行方式,周期为进水曝气5.5h,沉淀1.5h,搅拌时间0.5h,排水和闲置0.5h。试验结果表明,经该工艺处理后出水水质达到《污水综合排放标准》(GB8978—1996)一级排放标准。     

分段式SBR与传统SBR工艺对比研究

将传统SBR的曝气和沉淀过程在时间上进行分段,在不同段数厌氧/好氧/缺氧状态下的交替运行条件下,考察了分段式SBR工艺的运行情况并与传统SBR进行了对比研究.通过设计正交试验确定了传统SBR、二段式和三段式SBR最佳运行参数.结果表明:三段式SBR对COD、NH3-N、总磷的去除率可以达到97.33%、96.63%、99.76%.二段式SBR对COD、NH3-N、总磷的去除率可以达到96.98%、93.45%、98.63%,传统SBR对COD、NH3-N、总磷的去除率可以达到95.87%、88.47%、98.15%,由此可见分段式SBR较传统SBR对有机物、NH3-N和总磷有较好的去除效果.     

研究生论文摘要

亚硝酸型硝化的控制与反硝化除磷影响因子的研究研究生:陈鸣岐导师:任南琪(哈尔滨工业大学市政环境工程学院150090)反硝化除磷脱氮双泥工艺(Anaerobic-Anoxic/Nitrification,A2N)是以控制水体富营养化为目的的脱氮除磷新工艺,工艺中包括好氧SBR反应器和厌氧/缺氧SBR反应器。以模拟生活污水为处理对象,分别进行了厌氧/缺氧SBR间歇试验和好氧SBR的连续流试验,为下一阶段运行A2N动态试验提供运行参数的参考范围。在厌氧/缺氧SBR间歇试验中,采用厌氧/缺氧交替运行方式培养驯化反硝化聚磷污泥,结论如下:(1)当厌氧段的pH分别为8、7.5、7…     

城市污水脱氮除磷SBR在线控制系统研究

SBR采用进水—厌氧—好氧—缺氧—好氧—沉淀—出水的运行方式处理城市污水。反应器装备有DO、ORP和pH等在线检测传感器。DO、ORP和pH变化的一些特征点可以用来判断和控制SBR中污水脱氮除磷过程的各个步骤。这包括:厌氧时,ORP和pH的转折点对应磷的释放;一次好氧时,DO、ORP的氨肘和pH的氨谷对应硝化结束;缺氧时,ORP的硝酸盐膝和pH的硝酸盐峰对应反硝化结束;二次好氧时,DO、ORP碳肘对应剩余碳的氧化结束,pH的转折点对应聚磷结束。控制系统能进行全自动运行来完成污水的脱氮除磷。     

正交试验法优化好氧颗粒污泥培养条件的研究

利用自制的SBR反应器,在厌-好氧交替运行条件下,采用逐步提高进水负荷的调控方法培养好氧颗粒污泥。针对好氧颗粒污泥的特点,选取影响好氧颗粒污泥成粒的进水COD、进水C/N比、厌氧时长、水力停留时间和曝气量5个因素,采用正交试验方法,探索其对好氧颗粒污泥形成的影响度,找到好氧颗粒污泥形成的最优培养条件。实验证明:在现有实验条件下影响颗粒化率的显著程度依次为:进水COD—沉降时间—厌氧时长—进水C/N比—曝气量—水力停留时间。最优培养条件是进水COD为600~1 300 mg/L,沉降时间为10 m in,厌氧时长为30 m in,进水C/N为10∶1,曝气量为0.2 m3/h,水力停留时间为270 m in,此条件下培养的好氧颗粒污泥COD去除率和氨氮去除率分别达到96%和83%。     

“活性污泥法-上向流间歇膨胀缺氧生物滤池”系统脱氮技术研究

本文研究了“活性污泥法-上向流间歇膨胀缺氧生物滤池”脱氮系统.内容包括:通过正交试验确定系统最佳运行条件;缺氧生物滤池的脱氮机理分析及其脱氮动力学模式的建立;系统出水回用的可行性分析.正交试验选取曝气池水力停留时间HRT_曝,缺氧生物滤池水力停留时间HRT_滤两因素各三个水平,按L_9(3~4)正交表进行九组试验,并考虑因素间的交互作用.对正交试验结果进行极差、方差分析,结果表明:系统较佳运行条件为HRT_曝=9h、HRT_滤=2.76h;考虑进水水质对系统脱氮效果影响,最终确定系统最佳运行条件为HRT_曝=6h、HRT_滤=2.76h.最佳运行条件下,系统COD_(Cr)去除率为87.2 %、NO_x~-—N去除率为76.4%.缺氧生物滤池中COD_(Cr)、NH_4~+-N、NO_x~-—N浓度     

污水有机碳源和电子受体对除磷的影响

考察厌氧-缺氧SBR(A2SBR)工艺中主导生化反应过程及聚磷污泥的特性,为反硝化除磷脱氮工艺的应用提供运行控制参数.在稳定运行的A2SBR系统进水中分别投加NaAC和葡萄糖作为碳源,进行对比试验.结果表明,进水中的有机物越容易降解,反硝化除磷菌(DPB)厌氧释磷速率越快,后续的缺氧吸磷效果也越好.同时通过静态试验考察了不同浓度CODCr、NO3--N、不同类型电子受体对DPB反硝化除磷效果的影响.结果表明,进水CODCr为300 mg/L、NO3--N为60mg/L时反硝化除磷效果最佳,同时缺氧段瞬时投加NO3--N利于驯化DPB对NO2--N的适应性,可以实现DPB利用不同类型的电子受体进行吸磷作用.     

改良氧化沟工艺强化脱氮除磷试验研究

采用改良氧化沟试验装置处理生活污水。为了提高脱氮除磷效率,对改良氧化沟的曝气量进行了优化,在氧化沟的前三个廊道设置缺氧区,将其运行方式改变为缺氧—厌氧—缺氧好氧,在提高氮磷去除效率的同时降低了能耗。试验结果表明,稳定运行阶段,二沉池出水COD_(Cr)、TN、NH3 N和TP的平均浓度分别为37 mg/L、8.9 mg/L、0.5 mg/L和0.39 mg/L,平均去除率分别为92%、83%、99%和92%,均稳定达到了《城镇污水处理厂污染物排放标准》(GB 18918 2002)一级A标准要求。     

“活性污泥法+缺氧变速生物滤池”城市污水深度处理系统的试验研究

本文所研究的“活性污泥法十缺氧变速生物滤池”城市污水深度处理系统采用不投加任何药剂的一级硝化-反硝化工艺.研究内容包括:通过正交试验确定系统最佳运行条件;缺氧变速生物滤池的脱氮机理分析;缺氧变速生物滤池反应器反硝化脱氮动力学模式研究:系统出水回用的可行性分析.正交试验选取曝气池水力停留时间HRT_(曝)、缺氧变速生物滤池水力停留时间HRT_(滤)两因素各三个水平,按L_9(3~4)正交表共进行九组试验,并考虑因素间的交互作用.对正交试验结果进行极差、方差分析,结果表明:系统最佳运行条件为HRT_(曝)=4h、HRT_(滤)=3.52h,最佳运行条件下系统COD_(Cr),去除率为91.1%,缺氧变速生物滤池NO_x~- —N去除率为74.4%.缺氧变速生物滤池内生物膜平均厚度为128μm,为兼性异养反硝化菌与厌氧菌共生系统.针     

强化缺氧酸化工艺途径的探讨

介绍了采用A/O1·O2 工艺处理高浓度石油化工废水的设计与运行 ,探讨了缺氧酸化工艺存在的问题 ,指出可以通过在缺氧酸化池内设置填料 ;增设A池底泥回流系统 ,配合使用底池搅拌器和曝气系统 ;采用好氧上膜 ,缺氧转化菌种的A池挂膜方式 ,在A池中形成O -A工艺组合等途径 ,防止缺氧酸化池水解酸化菌流失及污泥沉淀厌氧死亡 ,提高缺氧酸化效果和COD去除率 ,从而达到改善酸化工艺综合功能的目的     

Coupled anaerobic-aerobic treatment of whey wastewater in a sequencing batch reactor: proof of concept.

A proof of concept was performed in order to verify if the coupling of anaerobic and aerobic conditions inside the same digester could efficiently treat a reconstituted whey wastewater at 21 degrees C. The sequencing batch reactor (SBR) cycles combined initial anaerobic phase and final aerobic phase with reduced aeration. A series of 24 h cycles in 0.5 L digesters, with four different levels of oxygenation (none, 54, 108 and 182 mgO2 per gram of chemical oxygen demand (COD)), showed residual soluble chemical oxygen demand (sCOD) of 683 +/- 46, 720 +/- 33, 581 +/- 45, 1239 +/- 15 mg L(-1), respectively. Acetate and hydrogen specific activities were maintained for the anaerobic digester, but decreased by 10-25% for the acetate and by 20-50% for the hydrogen, in the coupled digesters. The experiment was repeated using 48 h cycles with limited aeration during 6 or 16 hours at 54 and 108 mgO2gCODinitial(-1), displaying residual sCOD of 177 +/- 43, 137 +/- 38, 104 +/- 22 and 112 +/- 9 mgL(-1) for the anaerobic and the coupled digesters, respectively. The coupled digesters recovered after a pH shock with residual sCOD as low as 132 mg L(-1) compared to 636 mg L(-1) for the anaerobic digester. With regard to the obtained results, the feasibility of the anaerobic-aerobic coupling in SBR digesters for the treatment of whey wastewater was demonstrated.     

Specific SBR population behaviour as revealed by comparative dynamic simulation analysis of three full-scale municipal SBR wastewater treatment plants.

Three full-scale municipal sequential batch reactor (SBR) wastewater treatment plants (WWTPs) were investigated by dynamic simulation studies using ASM1. All three WWTPs showed similar kinetic and stoichiometric conditions in the SBR population behaviour after calibration of the models. The simulation results detected only a discrepancy to the ammonia online data during and shortly after shock loading under anoxic and anaerobic conditions that so far could not be adjusted by the ASM1 model. However, these differences did not severely affect the quality of the simulations nor the effluent flows. Additionally, in all cases a dynamic alpha factor curve occurred during the aeration phases that was verified by further oxygen transfer measurements. This might reveal new aspects for the process control, design and simulation of SBR WWTPs. A short lag phase was detected in many cases at the beginning of the first aeration phase.     

Achieving and maintaining of short-cut nitrification in a cyclic activated sludge system

A lab-scale Cyclic Activated Sludge Technology (CAST) system was operated more than 5 months to evaluate the effects of the operation mode on nitrogen removal performance and investigate a feasible method for achieving short-cut nitrification in the system. Results showed that nitrogen was removed by conventional biological nitrification and denitrification in traditional operation mode (fill/aeration 2 h, settle 1 h, decant 1 h), whereas short-cut nitrification and denitrification was the main nitrogen removal pathway in modified operation mode and the nitrogen removal performance was enhanced. Short-cut nitrification was successfully achieved in CAST system at 17 ± 1 °C by adjusting operation conditions and the average total nitrogen removal efficiency increased by 11.4% compared to traditional mode. It was assumed that low dissolved oxygen (<1.0 mg/L) limitation combined with free ammonia (0.28-0.34 mg/L) inhibition on nitrite-oxidizing bacteria caused nitrite accumulation in modified mode. During maintaining period of short-cut nitrification, preset aeration time enhanced ammonium-oxidizing bacteria dominance. It was also found that low DO could result in overgrowth of filamentous microorganisms and poor sludge settleability. The pH variation could provide effective information for controlling aeration duration in modified mode. However, no evident breakpoint appeared on pH and DO profiles in traditional mode.     

Nitrite accumulation followed by denitrification using sequencing batch reactor.

Biological ammonia-nitrogen removal utilizes two distinct processes, nitrification and denitrification. In nitrification, ammonia oxidizes to nitrite then to nitrate. In this study, elimination of nitrite oxidation to nitrate step was attempted in order to directly remove nitrite to nitrogen gas by denitrification. For this study the supernatant from an anaerobic digester was used as an ammonia source and a sequencing batch reactor (SBR) was employed. Emphasis was given to the evaluation of the operational factors affecting nitrite accumulation and the elucidation of kinetics for biological nitrification and denitrification. Accumulation of nitrite in the nitrification process was achieved by suppressing the growth of Nitrobacter, a nitrite oxidizer, by loading high concentration ammonia supernatant immediately after all ammonia in the previous loading was oxidized to nitrite. Nitrite oxidation was taking place as the solid retention time (SRT) was increased from 2.5 days to 3.0 days in a continuously aerated SBR mode with daily feeding. However, nitrite accumulation was achieved even at longer SRT of 5 days when the aeration and non-aeration periods were appropriately combined and the non-aeration period can be used for denitrification of the accumulated nitrite with a carbon source supplied.     

Performance evaluation of SBR treatment for nitrogen removal from tannery wastewater.

Performance of SBR treatment for nitrogen removal from tannery is evaluated for a wide range of wastewater temperature between 7 and 30 degrees C. A pilot-scale SBR unit fed with plain-settled wastewater is operated on site for this purpose. Effective nitrogen removal is sustained by adjustment of the sludge age from 28 to 5 days. Concentration profiles of nitrogen compounds within a selected complete SBR cycle during the steady state operation at different wastewater temperatures and sludge ages are evaluated by model simulation. System performance is also interpreted in terms of modeling and stoichiometric calculation. Additional nitrate loss was observed during aerobic period when the aeration intensity was reduced by the factor of 50%.     

Nitrite accumulation by aeration controlled in sequencing batch reactors treating domestic wastewater.

The feasibility of obtaining and keeping stable nitrite accumulation in Sequencing Batch Reactors (SBRs) treating domestic wastewater is studied. The final product of ammonium oxidation is either reproducible nitrate or nitrite depending on the aeration strategy. With the aerobic-anoxic sequence, two SBRs fed with domestic wastewater are operated in parallel. One SBR (SBR1) is controlled by the aeration control strategy, and the other SBR (SBR2) by alternate aeration control strategy. Based on the on-line indirect measurements of DO and pH, the relationship between pH (or DO) and nitrogen concentration (NH4+-N, NO(3-)-N and NO(2-)-N) is investigated. The result indicates that pH and DO can be used as control parameters for the real-time aeration control strategy to obtain nitritation in SBR treating domestic wastewater. The result of SBR1 indicates that long-term stable nitritation is possible at 32+/-1 degrees C. The result of SBR2 indicates that the aeration control strategy is necessary for nitritation during the acclimation period, because the nitrite accumulation disappears when the aeration is extended.     

Low temperature biological phosphorus removal and partial nitrification in a pilot sequencing batch reactor system

Partial nitrification and biological phosphorus removal appear to hold promise of a cost-effective and sustainable biological nutrient removal process. Pilot sequencing batch reactors (SBRs) were operated under anaerobic/aerobic configuration for 8 months. It was found that biological phosphorus removal can be achieved in an SBR system, along with the partial nitrification process. Sufficient volatile fatty acids supply was the key for enhanced biological phosphorus removal. This experiment demonstrated that partial nitrification can be achieved even at low temperature with high dissolved oxygen (>3 mg/L) concentration. Shorter solid retention time (SRT) for nitrite oxidizing bacteria (NOB) than for ammonia oxidizing bacteria due to the nitrite substrate limitation at the beginning of the aeration cycle was the reason that caused NOB wash-out. Controlling SRT should be the strategy for an SBR operated in cold climate to achieve partial nitrification. It was also found that the aerobic phosphorus accumulating organisms' P-uptake was more sensitive to nitrite inhibition than the process of anaerobic P-release.     

Initial examination of microwave pretreatment on primary, secondary and mixed sludges before and after anaerobic digestion.

The effects of microwave pretreatment on disintegration and mesophilic digestion of waste activated sludge (WAS), primary sludge (PS), combined (PS + WAS) sequencing batch reactor (SBR) sludge and anaerobically digested biocake were investigated by both household and bench scale industrial types microwaves at temperatures below and above boiling point. Pretreatment variables, temperature, intensity (cooking rate) and sludge concentration had statistically significant effects on solubilization. The microwave pretreatment also increased the bioavailability of sludge components under batch anaerobic digestion and enhanced the dewaterability of pretreated sludges after digestion. However, the level of improvements in solubilization and biodegradation from different waste sludges were different. While the largest improvement in ultimate biodegradation was observed in WAS, microwave irradiation only affected the rate of biodegradation of pretreated PS samples. Similarly, relatively lower solubilization ratios achieved for combined - SBR sludge was attributed to high sludge age of extended aeration SBR unit. It is possible that initial sludge characteristics may influence final pretreatment outcomes so that general statements of performance cannot always be made.