原位臭氧氧化对活性污泥系统硝化和反硝化作用的影响研究

将厌氧序批式间歇反应器(ASBR)和序批式间歇反应器(SBR)串联组成污泥减量新工艺,着重探讨了对SBR段进行原位臭氧投加时,臭氧氧化作用对系统硝化和反硝化能力的影响,并以不投加作为对照。结果表明,将臭氧原位投加到ASBR—SBR组合工艺的SBR段,臭氧投加量为0.027g(以每克MLSS计),每隔3个周期再次投加、连续运行40d,试验组SBR段臭氧投加当期出水COD去除率为86%,比对照组下降了9百分点,但臭氧氧化细胞内大量有机物进入混合液中,为反硝化作用提供了外加碳源,对污泥反硝化能力的提高起到了一定的促进作用;试验组部分硝化细菌由于臭氧的强氧化作用而失去活性,但是随着剩余污泥量的减少,系统的污泥龄延长,有利于硝化细菌的生长,使得系统的硝化能力基本未受影响;试验组臭氧投加当期SBR段出水NO2--N平均浓度比对照组的高18.9%,但经过3个周期的运行后,其SBR段出水NO2--N平均质量浓度降低至7.57mg/L,基本与对照组持平;试验组臭氧投加当期SBR段出水NO3--N的平均浓度高于对照组,但经过3个周期的运行后,试验组出水NO3--N平均浓度低于对照组;试验组臭氧投加当期SBR段出水TN和对照组的出水TN平均去除率分别为65%和75%,但试验组再经过3个周期的运行后,出水TN平均去除率可以达到72%。可见,原位投加臭氧并未对SBR段的硝化和反硝化能力产生明显的影响。     

污泥减量过程中臭氧氧化对硝化和反硝化影响的试验研究

采用AO工艺,考察了在污泥减量过程中臭氧(O3)氧化对生物系统硝化和反硝化能力的影响.结果表明,在每克SS中O3投量为0.05 g时,氧化后污泥中的CODcr由37.5 mg/L增至700mg/L,TN由4.86 mg/L增至36.6 mg/L,NH4 -N由0.353mg/L增至7.49 mg/L,NO3--N由2.19 mg/L增至5.15 mg/L.虽然氧化系统出水NH4 -N浓度略高于对照系统,但氧化系统NH4 -N的去除率大于98%,硝化能力基本没有受到O3氧化的影响.O3氧化污泥后增加的有机物作为附加的碳源循环至缺氧段,提高了反硝化的效果,当污泥氧化比例分别为10%、20%、30%时,进入缺氧段的CODCr/TN分别平均增至11.21、11.56、11.88,氧化系统的反硝化效果也随之分别提高5%、25%、37%.     

超声与碱耦合作用破解剩余污泥的效能分析

超声与碱耦合方法破解污泥,可破坏污泥絮体结构,使污泥胞内外物质进入水相.本试验采用超声与碱耦合方法破解剩余污泥,研究污泥破解过程前后SCOD、pH值以及氨氮的变化.经超声与碱耦合预处理后,污泥上清液SCOD有大幅度提高.当加碱调节污泥pH为12,超声破解30 min后,污泥溶液SCOD溶出率从3.96%增加到27.88%.加碱后污泥经超声破解,其pH值有所下降,污泥溶液氨氮值会有所增加,但变化幅度不大.污泥温度随破解时间的延长而明显提高,这有利于后续污泥厌氧消化.     

超声与碱耦合作用破解剩余污泥的效能分析

超声与碱耦合方法破解污泥,可破坏污泥絮体结构,使污泥胞内外物质进入水相.本试验采用超声与碱耦合方法破解剩余污泥,研究污泥破解过程前后SCOD、pH值以及氨氮的变化.经超声与碱耦合预处理后,污泥上清液SCOD有大幅度提高.当加碱调节污泥pH为12,超声破解30 min后,污泥溶液SCOD溶出率从3.96%增加到27.88%.加碱后污泥经超声破解,其pH值有所下降,污泥溶液氨氮值会有所增加,但变化幅度不大.污泥温度随破解时间的延长而明显提高,这有利于后续污泥厌氧消化.     

Performance of anaerobic waste activated sludge digesters after microwave pretreatment.

Effects of microwave pretreatment on waste activated sludge (WAS) in mesophilic semicontinuous digesters with acclimatized inoculum at solids retention times (SRTs) of 5, 10, and 20 days are presented. Batch digesters determined optimum microwave temperature, intensity, WAS concentration, and percentage of WAS pretreated for highest WAS solubilization (soluble to total chemical oxygen demand ratio [SCOD:TCOD]) and biogas production. Pretreatment results indicated the potential to damage floc structure and release 4.2-, 4.5-, and 3.6-fold higher soluble proteins, sugars, and SCOD:TCODs compared with controls, with nucleic acid release. Pretreatment increased dewaterability and bioavailability of WAS with 20% higher biogas production compared with controls in batch digestion. In semicontinuous digesters, relative (to control) improvements in removals dramatically increased, as SRT was shortened from 20 to 10 to 5 days, with 23 and 26% higher volatile solids removals for WAS pretreated to 96 degrees C by microwave and conventional heating at a 5-day SRT.     

土霉素对剩余污泥中温厌氧消化的短期和长期影响

在中温(35℃)条件下,考察了土霉素(OTC)对剩余污泥厌氧消化的短期和长期影响。在短期影响实验中,采用间歇实验装置研究了OTC浓度为5、50和500 mg/L时对累计甲烷产气量的影响。结果表明,50 mg/L的OTC短期暴露下中温厌氧消化污泥的产甲烷活性会受到急性抑制,但经过141 h的驯化后系统能够恢复产气,表明中温厌氧污泥经过驯化后,可处理含高浓度OTC的剩余污泥。采用完全混合反应器进行了为期230 d的OTC长期影响实验,反应器进泥中OTC浓度从0 mg/L逐步提高为40、200和1 000 mg/L,通过定期监测产气量、甲烷含量和挥发性脂肪酸等指标来表征反应器的运行状况。当OTC浓度≤200 mg/L时系统产气量和气体中甲烷含量稳定并且消化液中挥发性脂肪酸未出现累积,表明厌氧系统未受到影响。但在OTC浓度为1 000 mg/L时运行43 d(2个污泥停留时间)后,污泥中发酵产酸细菌类群代谢活性受到抑制,导致系统产气量下降。上述结果表明,经过驯化,中温厌氧消化系统可处理OTC浓度≤200 mg/L的剩余污泥。     

优势菌的筛选及其强化活性污泥好氧反硝化的研究

利用含活性污泥提取物的贫培养基筛选SBR系统中的好氧异养优势菌。结合自然温度（15～20℃）、延长培养时间等条件来提高菌群的可培养性。从SBR活性污泥系统中分离出5种细菌。4株去除COD优势菌,1株异养硝化细菌,能在好氧条件下实现对总氮的去除。反应池底采用边缘对称曝气,反应池内细菌在时间顺序和空间位置上循环经历好氧过程及微氧过程。将PVA铝盐法固定的细菌对反应器进行生物强化。结果显示,在好氧工艺的条件下,投加优势菌群后,与未加优势菌群的反应器相比,可以显著改善污泥的沉降性能,COD、NH₃-N和TN降解率显著提高,分别达到98%、97%和90%。生物强化作用明显,反应器内具有良好的好氧反硝化环境。     

Effects of sludge properties on the thickening and dewatering of waste activated sludge.

The thickening and dewatering of waste activated sludge, from a pilot-scale submerged membrane bioreactor and two bench-scale, complete-mix activated sludge reactors (high-shear and low-shear aeration) treating the same municipal primary effluent, were investigated. Solids settling and compaction were measured using the diluted sludge volume index (DSVI) analysis and a batch centrifugation analysis, respectively. Elevated levels of filamentous microorganisms resulted in higher DSVI values and lower centrifuged pellet concentration. Elevated levels of nocardioform bacteria resulted in lower solids float concentrations, and higher colloidal material reduced solids recovery in batch flotation experiments. Sludge filterability, measured as time-to-filter, was shown to be a function of extracelluar polymeric substances and colloidal material, where higher levels of either reduced sludge filterability. Additional research is necessary to confirm these results using full- or demonstration-scale thickening and dewatering units.     

Evaluation of the persistence of micropollutants through pure-oxygen activated sludge nitrification and denitrification.

The persistence of pharmaceuticals, hormones, and household and industrial chemicals through a pure-oxygen activated sludge, nitrification, denitrification wastewater treatment facility was evaluated. Of the 125 micropollutants that were tested in this study, 55 compounds were detected in the untreated wastewater, and 27 compounds were detected in the disinfected effluent. The persistent compounds included surfactants, fire-retardant chemicals, pesticides, fragrance compounds, hormones, and one pharmaceutical. Physical-chemical properties of micropollutants that affected partitioning onto wastewater solids included vapor pressure and octanol-water partition coefficients.     

超声与次氯酸钠耦合预处理剩余污泥的中温厌氧消化效果

以某城市污水处理厂剩余污泥为对象,通过实验研究了超声与次氯酸钠预处理对污泥的溶胞效果,以及对后续厌氧消化的影响。结果表明,超声与次氯酸钠耦合作用最优操作条件为超声声能密度1.0 W/mL,作用时间50 min。在此条件下,次氯酸钠投加量为4.023 mg/g SS时,对污泥厌氧消化改善效果最明显,剩余污泥产气率及甲烷含量较对照组分别提高了69.73%和10%。同时污泥VSS去除率由11.11%提高到21.24%,在一定程度上实现了污泥减量。     

连续流动态膜餐厨垃圾和剩余污泥厌氧混合发酵系统的运行效能

为探究厌氧动态膜生物反应器(DMBR)在典型城市有机废弃物厌氧发酵领域应用的可行性,以餐厨垃圾(FW)和剩余污泥(WAS)为处理对象,在连续流条件下探究动态膜FW和WAS厌氧混合发酵系统的运行效能,并优化基质混合比(FW/WAS)和食微比(F/M)。结果表明,以水力停留时间(HRT)和有机负荷(OLR)分别为62.5 d和(1.84±0.45) g·L⁻¹·d⁻¹为初始条件,在连续流下启动FW和WAS厌氧混合发酵系统,经过72 d的运行,系统pH稳定在7.6~8.0,平均甲烷产量达到(0.41±0.08) L·L⁻¹·d⁻¹,无短链挥发性脂肪酸(VFA)累积且TVFA/碱度最大比值仅为0.024,表明系统启动成功且运行稳定。通过对动态膜的特性分析可知,动态膜形成快速,可在较短时间内实现低浊度(<50 NTU)出料,动态膜截留效果显著。通过FW/WAS和F/M的批次优化实验可知,厌氧混合发酵系统最优FW/WAS为4.4∶1 (基于VS),定期调整优化FW/WAS有望取得更高的系统甲烷产率;相应的系统能够耐受的最大F/M为0.944,为后续充分发挥连续流动态膜FW和WAS混合发酵系统的最大效能提供依据。本研究结果可为典型城市有机废物厌氧发酵产甲烷系统的低碳高效稳定运行提供参考。     

温度和污泥浓度对碱性条件下剩余污泥水解酸化的影响

挥发性脂肪酸(VFAs)是脱氮除磷过程中易于利用的碳源。剩余污泥在碱性条件下发酵能产生大量的VFAs,而温度和污泥浓度是影响剩余污泥发酵的两个重要因素,为此考察了厌氧环境,温度15℃和35℃,pH为10的条件下,剩余污泥挥发性悬浮污泥浓度(VSS为1.708～11.049 g/L)对水解酸化的影响,为实现剩余污泥的资源化提供理论依据。研究得出如下结论:污泥浓度对剩余污泥溶解性化学需氧量(SCOD)溶出率影响不大。低污泥浓度和高污泥浓度均不利于剩余污泥产酸,最佳产酸的污泥浓度为8.540 g/L。各污泥浓度条件下产生的6种挥发性有机酸中乙酸的比例总是最大,且低污泥浓度条件下乙酸的百分含量要高于高污泥浓度条件下。温度对高污泥浓度条件下污泥的最大SCOD溶出量影响较大,而对低污泥浓度条件下污泥最大的产酸量影响较大。无论15℃还是35℃,中等污泥浓度对氨氮的释放量影响不大,35℃条件下污泥浓度对正磷酸盐的释放要比15℃条件下大。     

剩余活性污泥和厨余垃圾续批式混合中温消化试验研究

将加碱水解和未水解剩余活性污泥与厨余垃圾混合后进行序批式中温厌氧消化,对生化产甲烷势(BMP)进行了测定.剩余活性污泥的水解通过添加NaOH进行,合理的NaOH投量为40 mmol/L,在25 ℃和35 ℃下经过6 h的水解后SCOD水解率分别提高27.4%和31.1%.厨余垃圾、25℃和35℃下水解污泥的最终甲烷产量分别为607、284、312 mL/g(VS),两种水解污泥比未水解污泥分别高出43%、57.6%,水解污泥和厨余垃圾混合消化的可降解能力要优于未水解污泥和厨余垃圾的混合进料.     

pH值对污泥发酵产酸的影响

利用剩余污泥厌氧发酵产生挥发性脂肪酸,可作为污水脱氮除磷的有机碳源,而pH值是发酵产酸过程中重要的控制参数.研究了不同pH值条件下剩余污泥厌氧发酵产酸过程中各参数变化规律,探索pH值对其过程的影响及其分析.结果表明,碱性条件有利于污泥发酵产酸过程,实验最佳条件是控制反应初始pH值为10.0,仅8d发酵挥发性脂肪酸浓度就达到8.90 mmol/L.此外,污泥在发酵过程中,酸性条件下NH4+-N和PO43--P的释放量均大于碱性条件.     

VFA generation from waste activated sludge: effect of temperature and mixing

The success of enhanced biological phosphorus removal (EBPR) depends on the constant availability of volatile fatty acids (VFAs). To reduce costs, waste streams would be a preferred source. Since VFAs were shown to vary in the incoming sewage and fermentate from primary sludge the next available source is waste activated sludge (WAS). The opportunity is particularly good in plants where WAS is stored before shipment. Little information is however available on the rate of VFA release from such sludge, especially at the lower temperatures and under the storage conditions typically found in colder climates. Bench-scale batch tests were performed to investigate the effect of temperature and requirement for mixing on VFA generation from WAS generated in full scale non-EBPR wastewater treatment plant. WAS fermentation was found highly temperature-dependent. Hydrolysis rate constant (k_h) values of 0.17, 0.08 and 0.04 d⁻¹ at 24.6, 14 and 4 °C were obtained, respectively. Arrhenius temperature coefficient was calculated to be 1.07. It took 5 d to complete hydrolysis at 24.6 °C, 7 d at 14 °C, and 9 d at 4 °C. The fermentation lasted for 20 d. At 24.6 °C the mixed reactor reached 84% of the overall VFA production only in 5 d. When temperature dropped to 14 and 4 °C, the ratio of VFA production at day 10 to overall VFA production in the mixed reactor were 62% and 48%, respectively. The overall VFA-COD concentration in the non-mixed reactors was much lower than the mixed reactors. The information is important for the designer as there was uncertainty with the effect of temperature and mixing on sludge fermentation.     

剩余污泥氮磷营养盐提取方法研究

为提取污泥中的氮磷营养盐,以实现污泥的资源化和减量化,分别采用热碱法、超声波法和加碱超声波法对剩余污泥进行处理.在优化提取工艺条件的基础上,比较了3种方法对污泥中无机氮(IN)和磷酸盐(PO34--P)的提取效果以及污泥减量效果.结果表明,热碱法的适宜提取条件为pH=13、T=100℃、t=9 h;超声波法的适宜提取条...     

基质组分对厨余与污泥共发酵动力学特性的影响

通过厌氧发酵4阶段动力学实验、产甲烷抑制实验及单一VFA的产甲烷动力学实验,探明了厨余和污泥共发酵过程中,典型组分对其潜在的酸积累类型以及甲烷化过程的影响。结果表明,不同基质组分在厌氧发酵过程中的VFA组成比例以及单一VFA的产甲烷化动力学特性,对其产甲烷潜能及速率有着决定性影响。乙酸的甲烷化速率高达44.80 mL·d-1,丁酸略慢于乙酸,而丙酸和戊酸的甲烷化速率不足乙酸的1/2,其中丙酸的延滞期长达1.76 d。因此,产酸类型以乙酸为主的污泥、菜类在产甲烷阶段不存在延滞期;而蛋肉类及油的产甲烷速率受到丙酸、戊酸动力学特性的影响相对较慢。通过调整共发酵基质配比不仅能够提高发酵潜能,还能够优化VFA组成比例,实现较高的甲烷产率及甲烷化速率。     

进料频率对餐厨垃圾与剩余污泥中温共发酵系统稳定性的影响

考察系统负荷(以COD计)为11.36 g·(L·d)-1时,6种不同进料频率下,餐厨垃圾和剩余污泥中温厌氧共发酵过程中产气量、气体组分、SCOD、pH和挥发性脂肪酸(VFAs)的变化,旨在明确进料频率对系统稳定性的影响,同时结合单一VFA的产甲烷动力学特性,探明系统不稳定的原因。结果表明,进料频率较高时,进料周期内系统的气体组分、SCOD和pH无明显变化,产气量呈线性增长,且基本无VFA积累。随着进料频率降低,进料初期过快的水解酸化导致SCOD和VFAs浓度呈现明显的先升高后逐渐降低的趋势,从而导致pH和甲烷含量波动明显。当进料频率为1 次·d-1时,系统中pH降至7.5,甲烷含量降至45.4%,丙酸占总有机酸的比例最高可达87.9%。相比乙酸而言,丙酸在甲烷化过程中存在的延滞期(1.21 h)及较低的甲烷化速率(5.01 mL·h-1)可能是导致存在丙酸积累的低频进料系统中稳定性较差的原因之一。     

超声破解污泥影响因素分析

超声破解是促进污泥快速厌氧消化的一项新技术,不仅超声波参数直接影响污泥破解效果,而且污泥性质和辅助条件也影响污泥破解效果.以污泥溶解性化学需氧量增加值(SCOD )和污泥破解度(DDSCOD)为评价参数,通过超声破解不同性质污泥试验,得出污泥的初始温度、pH值和污泥浓度等参数对污泥破解效果起重要作用.增加搅拌和曝气辅助条件破解污泥的试验,得出间歇搅拌和曝气能增强污泥超声破解效果.     

Release of phosphorus from sewage sludge during ozonation and removal by magnesium ammonium phosphate

Environmental Science and Pollution Research - The release rule of phosphorus from sewage sludge during ozonation and removal by the magnesium ammonium phosphate (MAP) method were investigated. The...