高负荷厌氧氨氧化的稳定性试验研究

为探讨高负荷条件下复合式UASB反应器中厌氧氨氧化反应的脱氮性能和稳定性,在已经成功启动并稳定运行的厌氧氨氧化反应器中,通过提高进水总氮浓度和缩短水力停留时间两种方式提高总氮负荷,考察脱氮效果。结果表明,通过逐步提高进水总氮浓度和缩短HRT可以提高厌氧氨氧化反应的总氮负荷,并获得理想的脱氮效果和运行稳定性,但过高的亚硝态氮浓度会对反应产生一定的抑制作用。     

注浆法在治理自燃矸石山工程中的应用

通过分析矸石自燃原理,提出采用注浆法对自燃矸石山进行治理,并结合某煤矿工程中矸石山治理实例,依据相关检测标准,证明了注浆法是治理自燃矸石山的一种有效方法。     

进水N/S值对同步脱硫反硝化特性的影响

研究了不同进水N/S值条件下,不同接种物的厌氧体系的同步脱硫反硝化特性。结果表明:在N/S为0.6或0.4的条件下,3个体系对硫化物的去除率均达到90%以上,其中以进水N/S为0.4时产生的悬浮态硫最多;硝态氮的去除特性与硫化物不同,3个体系对硝态氮的去除率均在进水N/S为1.0时达到100%,且此时N2的产量也最大。可见,尽管同步脱硫反硝化工艺具备同时脱氮及除硫的能力,但其进水N/S的控制值却不相同。对于脱硫而言,最佳的进水N/S为0.4;对于脱氮而言,最佳的进水N/S为1.0。此外,研究发现3个不同接种物的厌氧体系对硫化物及硝态氮的去除途径不同,进水N/S值的影响也有差异。对于接种了厌氧污泥的体系,存在自养反硝化和异养反硝化的竞争,改变进水N/S值可调节二者的竞争,高N/S值会抑制硫化物自养反硝化过程,降低对硫化物的去除率;对于接种脱氮硫杆菌的纯菌体系,多硫自催化反应会与硫化物自养反硝化反应竞争硫化物,降低对硝态氮的去除率,高N/S值会导致出水硝态氮浓度较高;对于添加脱氮硫杆菌的强化厌氧污泥体系,以硫化物自养反硝化过程为主,最佳的N/S为0.4。     

Development of a 2-sludge, 3-stage system for nitrogen and phosphorous removal from nutrient-rich wastewater using granular sludge and biofilms

A novel 2-sludge 3-stage process using a combination of granular sludge and biofilm was developed to achieve biological removal of nitrogen and phosphorus from nutrient-rich wastewater. The system consists of a granular sequencing batch reactor (SBR) working under alternating anaerobic/anoxic conditions supplemented with a short aerobic phase and an aerobic biofilm SBR. The wastewater is first fed to the granular SBR reactor, where easily biodegradable carbon sources are taken up primarily by polyphosphate accumulating organisms (PAOs). The supernatant resulting from quick settling of the granular sludge is then fed to the biofilm SBR for nitrification, which produces oxidized nitrogen that is returned to the granular reactor for simultaneous denitrification and phosphorus removal. While maximizing the utilization of organic substrates and reducing operational costs, as do other 2-sludge processes previously reported in literature, the proposed system solves the bottleneck problem of traditional 2-sludge systems, namely high effluent ammonia concentration, due to its high-volume exchange ratios. An ammonia oxidation rate of 32 mg N/Lh was achieved in the biofilm SBR, which produced nitrite as the final product. This nitrite stream was found to cause major inhibition on the anoxic P uptake and also to result in the accumulation of N(2)O. These problems were solved by feeding the nitrite-containing stream continuously to the granular reactor in the anoxic phase. With a nitrogen and phosphorus removal efficiency of 81% and 94%, respectively, the system produces an effluent that is suitable for land irrigation from a wastewater stream containing 270 mg N/L of total nitrogen and 40 mg P/L of total phosphorus.     

Advancing post-anoxic denitrification for biological nutrient removal

The objective of this research was to advance a fundamental understanding of a unique post-anoxic denitrification process for achieving biological nutrient removal (BNR), with an emphasis on elucidating the impacts of surface oxygen transfer (SOT), variable process loadings, and bioreactor operational conditions on nitrogen and phosphorus removal. Two sequencing batch reactors (SBRs) were operated in an anaerobic/aerobic/anoxic mode for over 250 days and fed real municipal wastewater. One SBR was operated with a headspace open to the atmosphere, while the other had a covered liquid surface to prevent surface oxygen transfer. Process performance was assessed for mixed volatile fatty acid (VFA) and acetate-dominated substrate, as well as daily/seasonal variance in influent phosphorus and ammonia loadings. Results demonstrated that post-anoxic BNR can achieve near-complete (>99%) inorganic nitrogen and phosphorus removal, with soluble effluent concentrations less than 1.0 mgN L⁻¹ and 0.14 mgP L⁻¹. Observed specific denitrification rates were in excess of typical endogenous values and exhibited a linear dependence on the glycogen concentration in the biomass. Preventing SOT improved nitrogen removal but had little impact on phosphorus removal under normal loading conditions. However, during periods of low influent ammonia, the covered reactor maintained phosphorus removal performance and showed a greater relative abundance of polyphosphate accumulating organisms (PAOs) as evidenced by quantitative real-time PCR (qPCR). While GAOs were detected in both reactors under all operational conditions, BNR performance was not adversely impacted. Finally, secondary phosphorus release during the post-anoxic period was minimal and only occurred if nitrate/nitrite were depleted post-anoxically.     

Integrated removal of nitrate and carbon in an upflow anaerobic sludge blanket (UASB) reactor: Operating performance

Denitrification and methanogenesis of a synthetic wastewater containing volatile fatty acids and nitrate were obtained in a single-stage process using an upflow anaerobic sludge blanket (UASB) reactor. The reactor was initially inoculated with methanogenic granular sludge and was gradually adapted to nitrate by increasing the nitrate concentration in the influent. Excess carbon not utilized for denitrification was converted to methane. During steady-state at a loading of 336 mg NO₃-N/l/d (24 mmol NO₃/l/d) and 6600 mg COD/l/d more than 99% removal of both nitrate and carbon was achieved. Batch experiments with biomass from the reactor showed that approximately 90% of the added nitrate was recovered as nitrogen gas indicating that true dentrification occurred. This was further verified from mass balances over the reactor. The granules changed appearance during the first 5 months of operation being fluffy and buoyant, probably reflecting changes in the microbial composition induced by the presence of nitrate. However, during the next two months more dense granules with good settling abilities gradually established in the system making this kind of combined process feasible in a UASB reactor. Characterization of the produced granules showed that while the mean diameter and density was comparable to granules from purely methanogenic systems, although the strength was lower.     

Innovative process scheme for removal of organic matter, phosphorus and nitrogen from pig manure

Disposal of pig manure often requires treatment with respect to environmental legislations. In this study different processes for reduction of the organic matter (anaerobic digestion, effluent separation by decanter centrifugation, membrane microfiltration, post-digestion in upflow anaerobic sludge blanket (UASB) reactor, partial oxidation), nitrogen (oxygen-limited autotrophic nitrification-denitrification, OLAND) and phosphorus (phosphorus removal by precipitation as struvite, PRS) from pig manure were tested. Results obtained showed that microfiltration was unsuitable for pig manure treatment. PRS treated effluent was negatively affecting the further processing of the pig manure in UASB, and was therefore not included in the final process flow scheme. In a final scheme (PIGMAN concept) combination of the following successive process steps was used: thermophilic anaerobic digestion with sequential separation by decanter centrifuge, post-digestion in UASB reactor, partial oxidation and finally OLAND process. This combination resulted in reduction of the total organic, nitrogen and phosphorus contents by 96%, 88%, and 81%, respectively.     

A novel sulfate reduction, autotrophic denitrification, nitrification integrated (SANI) process for saline wastewater treatment

This paper reports on a lab-scale evaluation of a novel and integrated biological nitrogen removal process: the sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process that was recently proposed for saline sewage treatment. The process consisted of an up-flow anaerobic sludge bed (UASB) for sulfate reduction, an anoxic filter for autotrophic denitrification and an aerobic filter for nitrification. The experiments were conducted to evaluate the performance of the lab-scale SANI system with synthetic saline wastewater at various hydraulic retention times, nitrate concentrations, dissolved oxygen levels and recirculation ratios for over 500 days. The system successfully demonstrated 95% chemical oxygen demand (COD) and 74% nitrogen removal efficiency without excess sludge withdrawal throughout the 500 days of operation. The organic removal efficiency was dependent on the hydraulic retention time, up-flow velocity, and mixing conditions in the UASB. Maintaining a sufficient mixing condition in the UASB is important for achieving effective sulfate reduction. For a typical Hong Kong wastewater composition 80% of COD can be removed through sulfate reduction. A minimum sulfide sulfur to nitrate nitrogen ratio of 1.6 in the influent of the anoxic filter is necessary for achieving over 90% nitrate removal through autotrophic denitrifiers which forms the major contribution to the total nitrogen removal in the SANI system. Sulfur balance analyses confirmed that accumulation of elementary sulfur and loss of hydrogen sulfide in the system were negligible.     

预处理/厌氧生物处理敌百虫生产废水的研究

对敌百虫生产废水的处理工艺进行了研究,先采用破乳法和电解法进行预处理,然后再采用升流式厌氧污泥床(UASB)工艺进行厌氧处理,试验历时90 d,考察了系统的稳定性及pH值、温度和水力停留时间(HRT)等对反应器的影响。结果表明,当温度控制在30～35℃、pH值为6.8～7.5、进水COD为12 000 mg/L、HRT为72 h时,对COD的去除率可达到73%以上;厌氧处理后采用除磷药剂进行混凝沉淀,出水总磷浓度降为618 mg/L,对总磷的去除率为75.36%。     

Enrichment culture of marine anaerobic ammonium oxidation(anammox) bacteria

The present study investigates the enrichment of anaerobic ammonium oxidation(anammox)bacteria in the marine environment using sediment samples obtained from the East China Sea and discusses the nitrogen removal efficiency of marine anammox bioreactor.Enrichment of anammox bacteria with simultaneous removal of nitrite and ammonium ions was observed in the Anaerobic Sequencing Batch Reactor under a total nitrogen loading rate of 0.37kg-N m-3day-1.In this study,The nitrogen removal efficiency was up to 80%and the molar-reaction ratio of ammonium,nitrite and nitrate was 1.0:1.22:0.22 which was a little different from a previously reported ratio of 1.0:1.32:0.26 in a freshwater system.     

固定化酶酸化反应器/UASB处理黄浆废水的研究

针对现有两相厌氧反应器微生物易流失以及单方面延长酸化相的停留时间导致的过酸化影响后续甲烷化过程的现象，开发了一套新型两相厌氧处理系统，其酸化相是采用大孔树脂固定化酶作生物载体的水解酸化反应器，产甲烷相则是接种了经长期驯化培养的高温厌氧污泥的UASB。采用该装置处理玉米加工过程中产生的富含蛋白质废水（黄浆废水），考察了进水COD浓度和负荷、C／N值等因素对系统处理效能的影响。结果表明：该装置运行稳定，在低C／N值和低负荷条件下，酸化相的酸化率（VFA／COD）即可达30％以上，其出水pH值稳定在6．7～7．0；产甲烷相对COD的去除率为91．3％，进水C／N值对产甲烷相去除COD有明显影响。     

(AO)2-SBBR反硝化除磷工艺处理低碳城市污水

低碳源浓度城市污水的脱氮除磷一直是个难题，为此在AO-SBBR工艺中引入一个缺氧段而形成（AO）2-SBBR工艺，研究了AO-SBBR和（AO）2-SBBR对低碳源浓度城市污水中氮、磷的去除效果。试验结果表明：在进水BOD5／TN=3、BOD5／TP=17的情况下，（AO）2-SB．BR工艺比AO-SBBR工艺具有更好的同步脱氮除磷效果，对总磷的去除率达到了79．8％，对总氮的去除率从25．83％提高到51．26％，出水水质达到了《城镇污水处理厂污染物排放标准》的一级标准。该工艺有效解决了低碳源浓度城市污水在同步脱氮除磷过程中有机物不足的问题，并在单一反应器中实现了反硝化除磷菌的增殖过程，反硝化除磷菌占聚磷菌的比例从14．82％增长到63．04％；反硝化除磷菌能够以低浓度的亚硝酸盐氮作为电子受体进行缺氧吸磷，如亚硝酸盐氮〉10mg／L则会抑制反硝化除磷菌的活性，而且这种抑制作用并不是瞬时的，至少要持续一段时间其活性才能恢复。     

Simultaneous methanogenesis and denitrification of pretreated effluents from a fish canning industry

A lab-scale hybrid upflow sludge bed-filter (USBF) reactor was employed to carry out methanogenesis and denitrification of the effluent from an anaerobic industrial reactor (EAIR) in a fish canning industry. The reactor was initially inoculated with methanogenic sludge and there were two different operational steps. During the first step (Step I: days 1-61), the methanogenic process was carried out at organic loading rates (OLR) of 1.0-1.25 g COD l-1 d-1 reaching COD removal percentages of 80%. During the second step (Step II: days 62-109) nitrate was added as KNO3 to the industrial effluent and the OLR was varied between 1.0 and 1.25 g COD l-1 d-1. Two different nitrogen loads of 0.10 and 0.22 g NO3(-)-N l-1 d-1 were applied and these led to nitrogen removal percentages of around 100% in both cases and COD removal percentages of around 80%. Carbon to nitrogen ratio (C:N) in the influent was maintained at 2.0 and eventually it was increased to 3.0, by means of glucose addition, to control the denitrification process. From these results it is possible to establish that wastewater produced in a fish canning industry can be used as a carbon source for denitrification and that denitrifying microorganisms were present in the initially methanogenic sludge. Biomass productions of 0.23 and 0.61 g VSS:g TOC fed for Steps I and II, respectively, were calculated from carbon global balances, showing an increase in biomass growth due to denitrification.     

电解法深度处理生活垃圾焚烧厂渗滤液研究

采用三元电极对垃圾焚烧厂渗滤液的生化-混凝出水进行电解处理，研究了其处理效果及影响因素。结果表明，在电解反应过程中COD的降解符合三级反应动力学，其t时刻的出水浓度为：Ct=（2kt＋C0^-2）^-0.5；电流、pH值、电解时间、氯离子浓度、进水COD浓度对有机物去除率的影响较大，而极间距、温度和极水比则影响较小。此外，考察了该电极对氮化合物的去除效果。结果表明，在电解过程中亚硝态氮很快被氧化成硝态氮，之后氨氮转化为氮气，总氮基本以硝态氮的形式存在。     

喷射环流反应器同步硝化反硝化机理的研究

喷射环流反应器在好氧条件下具有良好的脱氮性能,其对氨氮和总氮的去除率分别达到80%和70%以上,且两者的去除率成正比.试验测定了反应器出水中NOx^--N的含量,结果表明出水中的氮主要以氨氮和亚硝酸盐氮的形式存在,证明该反应器在硝化过程中实现了对亚硝酸盐的积累.反应器的脱氮效果随进水C/N值的增加而提高,证明了异养硝化细菌的存在.对废水处理过程中产生的废气进行气相色谱分析,结果表明废气中氮气的含量比空气的增加了0.24%,证明反应器中发生了反硝化反应.综合试验结果表明,喷射环流反应器中的脱氮机理为亚硝酸盐型同步硝化反硝化.     

Organic removal by denitritation and methanogenesis and nitrogen removal by nitritation from landfill leachate

A system consisting of a two-stage UASB and anoxic-oxic reactor was used to enhance COD and nitrogen removal from landfill leachate. To improve denitrification efficiency, the raw leachate with recycled final effluent was pumped into the first-stage UASB (UASB1) to carry out simultaneous denitrification and methanogenesis. The results over 180 d show that the maximum organic removal rate in UASB1 and UASB2 was 12.5 and 8.5 kgCODm(-3)d(-1) in the oxic zone of the A/O reactor, respectively. The COD and biochemical oxygen demand (BOD5) removal efficiency of the system was 80-92% and about 99%, respectively. Without controlling temperature (17-30 degrees C) and dissolved oxygen (0.5-4.0 mgL(-1)), the maximum NH4+-N removal rate was 0.68 kg NH4+-Nm(-3)d(-1), and about 99% of NH4+-N removal was obtained by nearly complete nitritation. The 81-93% total nitrogen removal was obtained by complete denitrification in the UASB1 and in the anoxic zone of the A/O reactor. Fluorescence in situ hybridization (FISH) analysis of the sludge samples from A/O reactor showed that ammonia oxidizing bacteria (AOB) consisted 4% of the eubacterium, while nitrite oxidizing bacteria (NOB) counted less than 0.2% of that. The study shows that the main factors achieving and maintaining nitritation are a proper range of free ammonia concentration obtained by dilution recycled final effluent that inhibits NOB but not AOB; effective control on aeration time by indication of "ammonia valley" on pH profile; and highly efficient denitrification and its reproducing alkalinity to result in pH above 8.5.     

短程硝化/厌氧氨氧化联合工艺处理含氨废水的研究

在SBR中接种普通好氧活性污泥,通过控制运行条件来实现短程硝化,同时提高厌氧生物转盘系统中厌氧氨氧化的氮负荷,使之与SBR出水中NO2--N的积累量相匹配,并将二者组合形成短程硝化/厌氧氨氧化自养脱氮工艺.处理含氨废水的试验结果表明:在SBR的进水NH4+-N为150～250 mg/L、温度为(28±2)℃、pH值为7～8、DO<1 mg/L的条件下,可实现稳定的短程硝化,NO2--N积累率达85%以上,NH4+-N负荷达0.129 kgN/(kgVSS·d),AOB和NOB的数量之比为103:1.将短程硝化出水加入NH4+-N后作为厌氧氨氧化反应器的进水,在(40±1)℃下可以达到自养脱氮的目的,对NH4+-N、NO2--N和TN的去除率分别达86%、97%和90%以上,TN容积负荷为0.488 kgN/(m3·d).     

进水氨氮对厌氧同步脱氮除硫工艺的影响

通过比较含氨氮和不含氨氮两种进水水质条件下接种物不同的两个反应器的脱氮除硫特性,研究进水氨氮对厌氧同步脱氮除硫性能的影响。结果表明,进水未加氨氮的反应器对硫化物和硝态氮的去除率均高达95%,当加入氨氮后,仅有40%～50%的硝态氮被去除,消耗1 g硫化物所还原的硝态氮量减少,去除硝态氮的能力降低了近50%,然而对硫化物的去除率仍维持在90%左右,表明脱氮过程比脱硫过程受进水氨氮的影响大。扫描电镜观察结果证实,当进水中存在氨氮时硫化物的毒性增大,杀死了大量的脱氮硫杆菌,降低了硫化物转化为单质硫的能力,干扰了系统的反硝化脱氮过程,这是导致体系脱氮能力降低的主要原因。     

基质比例对高负荷ANAMMOX-UASB装置运行的影响

在进水总无机氮负荷率约为13 kg/(m3.d)的条件下,通过改变无机配水中亚硝态氮与氨氮浓度的比例来考察其对厌氧氨氧化性能的影响。试验共分为5个阶段,各阶段的进水NO 2--N/NH 4+-N均值分别为0.87、1.03、1.16、1.27、1.48。在前4个阶段对NO 2--N的平均去除率变化不大,均在95%以上,在阶段五则降至82.28%;对NH4+-N的去除率从阶段一的74.94%逐步上升至阶段五的97.85%;在阶段四时厌氧氨氧化效果最好,对NH4+-N与NO2--N的平均去除率分别达到97.59%、95.25%。试验过程中跑泥和温度降低等现象均会使处理效果降低。对反应器各部位取样的分析表明,在5个不同阶段,至反应器中部对基质的去除率就已达90%以上。     

Selenate removal in methanogenic and sulfate-reducing upflow anaerobic sludge bed reactors

This paper evaluates the use of upflow anaerobic sludge bed (UASB) bioreactors (30 degrees C, pH=7.0) to remove selenium oxyanions from contaminated waters (790 microg Se L(-1)) under methanogenic and sulfate-reducing conditions using lactate as electron donor. One UASB reactor received sulfate at different sulfate to selenate ratios, while another UASB was operated under methanogenic conditions for 132 days without sulfate in the influent. The selenate effluent concentrations in the sulfate-reducing and methanogenic reactor were 24 and 8 microg Se L(-1), corresponding to removal efficiencies of 97% and 99%, respectively. X-ray diffraction (XRD) analysis and sequential extractions showed that selenium was mainly retained as elemental selenium in the biomass. However, the total dissolved selenium effluent concentrations amounted to 73 and 80 microg Se L(-1), respectively, suggesting that selenate was partly converted to another selenium compound, most likely colloidally dispersed Se(0) nanoparticles. Possible intermediates of selenium reduction (selenite, dimethylselenide, dimethyldiselenide, H(2)Se) could not be detected. Sulfate reducers removed selenate at molar excess of sulfate to selenate (up to a factor of 2600) and elevated dissolved sulfide concentrations (up to 168 mg L(-1)), but selenium removal efficiencies were limited by the applied sulfate-loading rate. In the methanogenic bioreactor, selenate and dissolved selenium removal were independent of the sulfate load, but inhibited by sulfide (101 mg L(-1)). The selenium removal efficiency of the methanogenic UASB abruptly improved after 58 days of operation, suggesting that a specialized selenium-converting population developed in the reactor. This paper demonstrates that both sulfate-reducing and methanogenic UASB reactors can be applied to remove selenate from contaminated natural waters and anthropogenic waste streams, e.g. agricultural drainage waters, acid mine drainage and flue gas desulfurization bleeds.