ATP as an indicator of biomass activity in thermophilic upflow anaerobic sludge blanket reactor

This work investigated the biomass activity in a thermophilic upflow anaerobic sludge blanket (UASB) reactor of wastewater treatment. Synthetic textile wastewater with pH 10-11, COD level of 2000-3000 mg/L was tested. Cellular adenosine triphosphate (ATP) in volatile solids (VS; mg ATP/gVS) was measured and expressed as specific ATP content to compare the biomass activity in up zone and lower zone in UASB reactor. The result shows that the specific ATP content based on total volatile solids (VS)in lower zone (0. 046 mgATP/gVS average) is much lower than that in up zone (0.62 mgATP/gVS average) due to high content of inactive biomass and high pH in lower zone. The SATP in up zone increases as HRT increases and approaches to a maximum value of 0.85 mgATP/gVS at HRT of 7h, then decreases. It shows most of the total VS in up zone represent active bacterial biomass at HRT of 7h. Rate of subtract utilization is directly related to the activity of microorganisms in the reactor. The effect of HRT on SATP in lower zone is not as significant as on SATP in up zone. The buffer capacity of the thermophilic UASB reactor is very good. It is the activity of sludge granules in lower zone that give the UASB reactor such a good buffer capacity to the inlet high pH.     

Autoheated thermophilic aerobic sludge digestion and metal bioleaching in a two-stage reactor system

A two-stage process has been developed for stabilization of sludge and removal of heavy metals from the secondary activated sludge with high rate of energy and time conservation.The first stage of the process involves autoheated thermophilic aerobic digestion at 55-60°C inoculated with less-acidophilic thermophilic sulfur-oxidizing microorganisms(ATAD).The results show that it is possible to maintain the autoheated conditions(55-60°C) in the ATAD reactor up to 24 hr,leading to reduction of 21% total solids(TS),27% volatile solids(VS),27% suspended solids(SS) and 33% volatile suspended solids(VSS) from the sludge.The sludge pH also decreased from 7 to 4.6 due to the activity of less-acidophilic thermophilic microorganisms.In the second stage operation,the digested sludge(pH 4.6,TS 31.6 g/L) from stage one was subjected to bioleaching in a continuous stirred tank reactor,operated at mean hydraulic retention times(HRTs) of 12,24 and 36 hr at 30°C.An HRT of 24 hr was found to be sufficient for removal of 70% Cu,70% Mn,75% Ni,and 80% Zn from the sludge.In all,39% VSS,76% Cu,78.2% Mn,79.5% Ni and 84.2% Zn were removed from the sludge in both the stages.     

Degradation of phenol in an upflow anaerobic sludge blanket(UASB) reactor at ambient temperatureKE

A synthetic wastewater containing phenol as sole substrate was treated in a 2.8 L upflow anaerobic sludge blanket(UASB) reactor at ambient temperature. The operation conditions and phenol removal efficiency were discussed, microbial population in the UASB sludge was identified based on DNA cloning, and pathway of anaerobic phenol degradation was proposed. Phenol in wastewater was degraded in an UASB reactor at loading rate up to 18 gCOD/(L·d), With a 1:1 recycle ratio, at 26(1℃, pH 7.0-7.5. An UASB reactor was able to remove 99% of phenol up to 1226 mg/L in wastewater with 24 h of hydraulic retention time(HRT). For HRT below 24 h, phenol degradation efficiency decreased with HRT, from 95.4% at 16 h to 93.8% at 12 h. It further deteriorated to 88.5% when HRT reached 8 h. When the concentration of influent phenol of the reactor was 1260 mg/L(corresponding COD 3000 mg/L), with the HRT decreasing(from 40 h to 4 h, corresponding COD loading increasing), the biomass yields tended to increase from 0.265 to 3.08 g/(L·d). While at 12 h of HRT, the biomass yield was lower. When HRT was 12 h, the methane yield was 0.308 L/(gCOD removed), which was the highest. Throughout the study, phenol was the sole organic substrate. The effluent contained only residual phenol without any detectable intermediates, such as benzoate, 4-hydrobenzoate or volatile fatty acids(VFAs). Based on DNA cloning analysis, the sludge was composed of five groups of microorganisms. Desulfotomaculum and Clostridium were likely responsible for the conversion of phenol to benzoate, which was further degraded by Syntrophus to acetate and H2/CO2. Methanogens lastly converted acetate and H2/CO2 to methane. The role of epsilon-Proteobacteria was, however, unsure.     

Degradation of phenol in an upflow anaerobic sludge blanket (UASB) reactor at ambient temperature

IntroductionPhenolistherawmaterialforthecommercialproductionofawidevarietyofresins ,includingphenolicresinsasconstructionmaterialsforautomobilesandappliances,expoxyresinsasadhesives ,andpolyamideforvariousapplications.Inaddition ,phenolsareoftenfoundinwas…     

UASB反应器处理异VC钠废水的启动特性研究

在污泥接种浓度为10g／L,水温35℃-38℃的条件下,采用逐渐加大进水量提高有机负荷的方式45d内可以完成UASB反应器处理异VC钠生产废水的启动。启动完成后UASB反应器的容积负荷为6kgCOD／（m^3·d）,CODcr去除率可以达到85％。调试过程中向反应器内加入适量FeSO4,可以使污泥在较短时间内实现颗粒化,形成粒径为1mm～2mm、沉降性能良好的颗粒污泥。反应器出水VFA保持在400mg／L以下并能比pH更灵敏的反应出反应器内部的环境变化。     

含盐染料废水高温厌氧处理工艺特性研究

研究升流式厌氧污泥床反应器(UASB)在高温条件下处理含盐染料废水的工艺特性及颗粒污泥性能。结果表明,在以常温厌氧絮状污泥为接种污泥,运行温度为(55±1)℃,水力停留时间为12h,含盐量为50000mg/L,CODCr为900~1000mg/L,染料活性红2(RR2)浓度为100mg/L条件下,78d达到运行稳定,CODCr和RR2去除率分别为44%和85%以上。反应器中高温耐盐厌氧颗粒污泥粒径为1.0~2.0mm,其生物相组成以短杆菌、球菌、丝状菌为主。     

高温厌氧膜生物反应器处理餐厨废水的启动

以除油后的实际餐厨废水为原料,在高温（50±1）℃条件下利用浸没式纤维膜生物反应器（AnMBR）进行连续厌氧消化试验,以水力停留时间（HRT）20d启动,HRT 15d运行,直到发生膜污染,试验共进行了50d.研究了反应器启动和运行期间的发酵特性和膜过滤性能.研究表明,反应器30d完成了启动,在HRT 15d条件下,甲烷产量达到578L/kgVS_in,COD和挥发性固体（VS）去除率均达到94%以上,膜出水总挥发性脂肪酸（TVFA）浓度为（103±77） mg/L,其中乙酸浓度为（98±28） mg/L.系统pH 8.26,具有良好的稳定性.膜通量设定为9L/（m²·h）,运行30d后发生了明显的膜污染,伴随着反应器内挥发性悬浮固体（VSS）浓度由8.1g/L逐渐增加到18/L.在处理高浓度餐厨废水时,AnMBR可以短时间启动且在8.5kgCOD/（m³·d）的高负荷条件下稳定运行,反应器中污泥浓度和溶解性微生物产物的增加导致膜过滤性能下降是导致膜污染的主要因素.     

Start-up strategies of UASB reactor for treatment of pharmaceutical wastewater

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高温厌氧膜生物反应器处理餐厨废水的启动

以除油后的实际餐厨废水为原料,在高温（50±1）℃条件下利用浸没式纤维膜生物反应器（AnMBR）进行连续厌氧消化试验,以水力停留时间（HRT）20d启动,HRT 15d运行,直到发生膜污染,试验共进行了50d.研究了反应器启动和运行期间的发酵特性和膜过滤性能.研究表明,反应器30d完成了启动,在HRT 15d条件下,甲烷产量达到578L/kgVS_in,COD和挥发性固体（VS）去除率均达到94%以上,膜出水总挥发性脂肪酸（TVFA）浓度为（103±77） mg/L,其中乙酸浓度为（98±28） mg/L.系统pH 8.26,具有良好的稳定性.膜通量设定为9L/（m²·h）,运行30d后发生了明显的膜污染,伴随着反应器内挥发性悬浮固体（VSS）浓度由8.1g/L逐渐增加到18/L.在处理高浓度餐厨废水时,AnMBR可以短时间启动且在8.5kgCOD/（m³·d）的高负荷条件下稳定运行,反应器中污泥浓度和溶解性微生物产物的增加导致膜过滤性能下降是导致膜污染的主要因素.     

包埋固定化微生物厌氧反应器启动特性研究

为克服难降解废水厌氧微生物反应器启动初期生物易流失和启动过程缓慢的缺点,将厌氧絮状污泥进行固定化包埋作为厌氧反应器的接种污泥处理有毒难降解的PTA废水,同时考察固定化细菌在厌氧反应器启动过程中的变化特性.结果表明,经过136 d的运行,反应器在COD有机负荷为3 kg.(m3.d)-1,水力停留时间为3~4 d的运行条件下,PTA废水的COD去除率可以达到75%~85%,且系统具有比较好的稳定性和生物量保持能力.另一方面,胞外聚合物(EPS)的变化、产甲烷菌DNA特异性扩增和包埋颗粒的扫描电镜观察结果表明,虽然包埋载体在一定程度上限制了传质速度,但包埋颗粒中的厌氧微生物在微生物相和数量上都仍有显著的变化和增长.     

活性染料高温厌氧生物降解研究

研究了升流式厌氧污泥床反应器(UASB)在高温条件下处理含盐活性红2(RR2)染料废水的工艺及RR2的降解机理.结果表明:运行温度为(55±1)℃,水力停留时间为12 h,进水ρ(NaCl),ρ(COD_Cr)和ρ(RR2)分别为50　000,1　000和100 mg/L的条件下,以驯化好的厌氧颗粒污泥为接种污泥, 运行10 d后反应器达到稳定,COD_Cr和RR2去除率分别为25%和90%以上.利用气相色谱－质谱联用(GC-MS)分析厌氧出水发现, RR2的生物降解途径为在厌氧条件下最先被还原的是较易断裂的偶氮键(NN),去除颜色后形成了芳香胺类化合物,一部分芳香胺类化合物通过水解和氧化作用进一步降解为更小分子的代谢物.      

核黄素对偶氮染料生物降解的影响

采用高温〔(55±1) ℃〕升流式厌氧污泥床(UASB)-常温三相好氧流化床组合工艺处理含盐偶氮染料活性艳红X-3B(RR2)废水,考察核黄素(VB₂)对染料的降解及活性污泥微生物相的影响.结果表明:在水力停留时间(HRT)为18 h,进水ρ(RR2)为40～100mg/L,ρ(COD_Cr)为800～1 200 mg/L,ρ(NaCl)为30 000～35 000 mg/L,UASB反应器的有机负荷为2～3 kg/(m3·d),三相好氧流化床有机负荷为0.3～0.4 kg/(kg·d)的条件下,ρ(VB₂)为5 mg/L时可以明显改善工艺的运行效果,RR2和COD_Cr的去除率均在95%以上;UASB及三相好氧流化床中活性污泥微生物以杆菌为主,核黄素的投加使得系统中菌体体积变小、总量减少.      

UASB启动运行特征及互营丙酸氧化菌定量分析

为揭示升流式厌氧污泥床（UASB）反应器启动运行效能与互营丙酸降解菌群数量之间的关系,以稀释的玉米淀粉生产废水为底物,考察了UASB启动期的运行特征,并采用实时荧光定量PCR技术（qPCR）分析了互营丙酸降解菌群（丙酸氧化菌和产甲烷菌）的演替规律.结果表明,在进水COD 2000mg/L和水力停留时间（HRT）24h条件下,经过38d的连续运行,COD去除率达到了91.9%.当HRT分阶段缩短至8h时,比产甲烷速率达到了315LCH₄/（kg COD·d）,且形成了沉降性能良好的颗粒污泥.qPCR检测结果表明,至少有5种已鉴定的丙酸氧化菌存在于UASB反应器中.Pelotomaculum propionicum为接种污泥中的主要丙酸氧化菌,约占检测到丙酸氧化菌总数的45.7%.它的数量随着HRT缩短不断减少.而Syntrophobacter sulfatireducens和S.wolinii的数量随着HRT缩短不断增加,并在启动完成时达到最大值,分别为1.3×10³,5.5×10³个16S rRNA基因拷贝数/ng DNA,演替成为成熟颗粒污泥中的优势丙酸氧化菌群.Methanobacterium和Methanosarcina为接种污泥中的主要氢营养型产甲烷菌和乙酸营养型产甲烷菌,其数量随着HRT的缩短而逐渐减少,而Methanospirillum和Methanosaeta的数量随HRT的缩短逐渐增加,成为成熟颗粒污泥中的优势产甲烷菌群.     

电解浮选用于活性污泥固液分离的研究

在装有Ti/RuO₂-IrO₂-TiO₂阳极、Ti阴极的电解浮选槽中进行了活性污泥固液分离的研究.考察了影响电解浮选性能的操作参数,这些参数包括水力停留时间、电流密度、进水SS浓度和进水pH值.研究表明,电解浮选是高效的固液分离单元,水力停留时间和电流密度是主要的影响因素.SS的去除率随着水力停留时间和电流密度的增加而增大;污泥负荷增加,SS的去除率下降;pH值影响电解产生微气泡的尺寸和污泥性质,但对SS的去除影响不大,实际应用中可以不调节pH值.进水SS约1 000mg/L时,当水力停留时间为20min,接触室电流密度为5 mA/cm²,分离区电流密度为2.5 mA/cm²,SS的去除率可达97%以上,此时的能耗为0.4～0.5(kW.h)/m³废水.电解浮选产生的浮渣含水率为95.9%,低于溶气气浮和二沉池的污泥含水率,对污泥减量化及其最终处置有较大的意义.     

UASB反应器处理CMC废水的启动特性研究

采用上流式厌氧污泥床(UASB)反应器,以高浓度羧甲基纤维素(CMC)废水为处理对象,研究了中温条件下UASB反应器的启动、颗粒污泥特性和废水处理效果.结果表明,采用接种颗粒污泥与消化污泥的混合泥进行培养,并逐步提高进水CMC废水浓度,运行80 d后,可实现UASB反应器的启动;当进水COD值达到4 000 mg/L,容积负荷6.86 kg/(m3.d),COD去除率在80%以上;反应器内污泥实现颗粒化,且颗粒污泥的比产甲烷活性良好.     

Enhancement of thermophilic anaerobic digestion of thickened waste activated sludge by combined microwave and alkaline pretreatment

Pretreatment of thickened waste activated sludge (TWAS) by combined microwave and alkaline pretreatment (MAP) was studied to improve thermophilic anaerobic digestion efficiency. Uniform design was applied to determine the combination of target temperature (110–210°C), microwave holding time (1–51 min), and NaOH dose (0–2.5 g NaOH/g suspended solids (SS)) in terms of their effect on volatile suspended solids (VSS) solubilization. Maximum solubilization ratio (85.1%) of VSS was observed at 210°C with 0.2 g-NaOH/g-SS and 35 min holding time. The effects of 12 different pretreatment methods were investigated in 28 thermophilic batch reactors by monitoring cumulative methane production (CMP). Improvements in methane production in the TWAS were directly related to the microwave and alkaline pretreatment of the sludge. The highest CMP was a 27% improvement over the control. In spite of the increase in soluble chemical oxygen demand concentration and the decrease in dewaterability of digested sludge, a semi-continuous thermophilic reactor fed with pretreated TWAS without neutralization (at 170°C with 1 min holding time and 0.05 g NaOH/g SS) was stable and functioned well, with volatile solid (VS) and total chemical oxygen demand (TCOD) reductions of 28% and 18%, respectively, which were higher than those of the control system. Additionally, methane yields (L@STP/g-CODadded, at standard temperature and pressure (STP) conditions of 0°C and 101.325 kPa) and (L@STP/g VSadded) increased by 17% and 13%, respectively, compared to the control reactor.     

UASB-MBR组合工艺处理黄连素废水的中试

为实现黄连素废水的规模化处理,针对黄连素废水可生化性差、有机污染物浓度高等特点,采用UASB-MBR(升流式厌氧污泥床-膜生物反应器)组合工艺,利用微生物的生化反应去除废水中的高浓度有机物和黄连素,考察在不同HRT(水力停留时间)下COD_Cr和黄连素的去除效果,并采用GC-MS(气相色谱-质谱联用仪)对系统进、出水中的特征污染物进行分析. 结果表明:①在UASB与MBR的HRT分别为96、66 h,84、58 h,72、50 h,60、41 h,以及进水ρ(COD_Cr)和ρ(黄连素)分别为2 030.0~3 660.0和19.0~400.0 mg/L的条件下,COD_Cr和黄连素的平均去除率均可达到90.0%以上,出水ρ(COD_Cr)平均值低于150.0 mg/L,ρ(黄连素)平均值低于4.0 mg/L. ②UASB与MBR的HRT分别为72、50 h为最佳运行条件. ③UASB可以明显降低废水中特征污染物的种类和浓度,UASB出水经MBR处理后,废水中的11种主要特征污染物均得到有效降解.      

厌氧颗粒污泥对五氯酚(PCP)的吸附、解吸及生物降解

以未驯化污泥接种的升流式厌氧污泥床反应器可形成降解五氯酚（PCP）的颗粒污泥．颗粒污泥去除PCP的主要机制是生物降解作用,而不是生物吸附作用．PCP在颗粒污泥上的吸附和解吸符合Freundlich等温方程,吸附和解吸的Freundlich常数K、1/n分别为0.7857mg/gSS、0.5079和1.1095mg/gSS、0.3782,部分PCP被不可逆吸附．与其它活或死的生物材料相比,本试验形成的颗粒污泥对PCP吸附量较小．该方程较准确地表达了UASB反应器内厌氧颗粒污泥对PCP吸附量的变化规律．     

Sludge granulation and e ciency of phase separator in UASB reactor treating combined industrial e uent

Sludge granulation and the effect of gas-liquid-solid separator （GLSS） design on the efficiency of upflow anaerobic sludge blanket （UASB） and upflow anaerobic sludge filter （UASF） reactors, operating at HRTs ranging from 3 to 12 h was investigated. VSS/TS ratio gradually increased in both the reactors with increasing sludge age （from 0.5 to more than 0.7 for UASB reactor and 0.012 to 0.043 for UASF reactor）. X-Ray diffraction analysis of the UASF sludge showed the presence of expanding clays revealing its additional absorption capability. Fuoraphyllite and albite precipitation related to excellular polymers of the microbial shell structure, showed the extended growth of microorganisms during sludge granulation. A gradual decrease （82%-69%） in COD removal with decreasing HRT was apparent in UASF reactor. In case of UASB reactor, this decrease was marginal because addition of GLSS device significantly improved （14%-20%） the overall efficiency of the UASB reactor. GLSS enhanced the efficiency of the UASB reactor by increasing the settleability of suspended particles and accelerating the coagulation of colloidal particles due to the velocity gradient.     

HRT对糖蜜废水发酵产氢的影响

采用自制的UASB反应器,以糖蜜废水为底物,接种絮状污泥进行HRT对发酵制氢的影响研究.结果表明:在温度为(37±1)℃,进水COD浓度为4 000 mg/L,出水pH为4.6～5的条件下,HRT在8～6 h范围时,反应器的产气速率和产氢速率达到最大并保持稳定,平均值分别为41 L/d和21 L/d左右,氢气含量稳定在...