A2N反硝化除磷脱氮系统处理生活污水研究

研究了生活污水COD／TN比值变化对A2N反硝化除磷脱氮新工艺去除氮、磷的影响情况。同时利用间歇试验着重探讨了DNPAOs污泥在不同硝态氮浓度、不同电子受体时的摄磷和放磷状况。A2N连续流工艺长期的运行结果表明：双泥系统的建立(生物膜硝化池独立于除磷污泥)可以降低碳源的好氧消耗,较大程度地减少聚磷菌和反硝化菌之间对碳源的竞争,同时保证了生长速率较小的硝化菌可以在稳定状态中生长,利于增强系统脱氮除磷的稳定性。     

碳源类型对AOA-SBR系统的除磷特性和菌群组成的影响

分别以乙酸钠、丙酸钠为碳源,采用厌氧-好氧-缺氧(AOA)模式运行SBR反应器,考察该系统内的除磷特性和聚磷微生物菌群结构。驯化25天后,两系统均表现出较为稳定的除磷效果,两系统稳定期磷的去除率分别在88%和97%左右。乙酸钠系统的污泥沉降性较好,污泥增长缓慢;丙酸钠系统的污泥除磷性能较好,生长速率快,但沉降性较差。荧光原位杂交(FISH)分析表明,两系统均富集出了大量的聚磷菌Accumulibacter,但类型上存在差异。乙酸钠系统内的Accumulibacter主要为II型,而I型Accumulibacter在丙酸钠系统内占主导地位。     

强化生物除磷系统中主要菌群的富集和培养

以SBR反应器为载体,接种具有除磷功能的活性污泥后分别富集了强化生物除磷(EBPR)系统中的2个主要微生物种群聚磷菌(PAO)和聚糖菌(GAO).以P/C和碳源种类这2个关键因素作为选择性条件控制富集的方向.高P/C下以乙酸丙酸交替富集Accumulibacter;在低P/C下以乙酸富集Competibacter,以丙酸富集α-GAO.在适当pH、温度、好氧段DO、进水负荷等条件下,富集这3类微生物取得了成功,富集结果是Accumulibacter占80%, 系统对PO3-4-P的去除率可达98%以上,Competibacter占90%,α-GAO也占有非常大的比例.此外一些细节如配水灭菌、配水充分溶解等因素也能决定富集的成败.     

充水比对厌氧-低氧生物除磷脱氮系统的影响

本文主要研究不同的充水比对厌氧-低氧生物除磷脱氮系统中氮和磷去除效果的影响,确定适合厌氧-低氧SBR工艺的最佳充水比,同时对过程中与氮和磷去除相关的一些重要的微生物中间代谢物进行了研究。     

膜生物反应器脱氮除磷工艺处理城市污水的工程应用

为强化城市污水脱氮除磷,研发了厌氧/缺氧/好氧/缺氧-膜生物反应器(A2/O/A-MBR)新工艺,并建设了设计处理规模为2万m3/d实际工程.对该工程的长期监测表明,出水C()D、TN、NH4+-N和TP的平均浓度分别为20.6、6.67、1.05、0.19 mg/L,优于《城镇污水处理厂污染物排放标准》中的一级A标准...     

MB（A2/O）工艺的好氧、缺氧摄磷及微生物特性

为开发高效除磷脱氮技术,研制了将MBR与A２桙O工艺有机集成的新型MB（A２/O）组合工艺。研究 了MB（A２/O）工艺处理城市污水的好氧、缺氧摄磷性能及微生物特性,并分析了其机理。结果表明：在 MB（A２/O）系统中,聚磷菌约占活性污泥总量的２０％～４０％,其中大量存在能够利用NOX－N作为电子受体 进行反硝化除磷的DPB,约占聚磷菌数量的３５畅６６％～６７畅８３％。好氧摄磷的平均速率为２畅３０mgP·gMLSS－１· h－１,最大摄磷速率为５.４４mgP·gMLSS－１·h－１;缺氧摄磷的平均速率为１     

污水处理厂A-A-O生物脱氮除磷工艺简介

<正>在城市生活污水处理厂,传统活性污泥工艺能有效去除污水中的BOD5和SS,但不能有效地去除污水中的氮和磷。如果含氮、磷较多的污水排放到湖泊或海湾等相对封闭的水体,则会产生富营养化导致水体水质恶化或湖泊退化,影响其使用功能。因此,在对污水中的BOD5和SS进行有效去除的同时,还应根据需要,考虑污水的脱氮除磷。其中A-A-O(厌氧-缺氧-好氧)为同步生物脱氮除磷工艺的一种。     

充水比对低能耗生物除磷脱氮系统的影响

以厌氧-低氧(0.15～0.45mg/L)条件下的序批式反应器(SBR)为研究对象,探讨了不同充水比对低能耗同时生物除磷脱氮系统的影响.结果表明:以充水比为0.3(SBR-A),0.5(SBR-B)或0.785为碳源(SBR-C),系统中均发生同时生物氮和磷的去除,低氧阶段氨氮被全部氧化,并且没有亚硝酸盐的大量累积.随着充水比的增加,系统中厌氧末磷的释放量逐渐增加,PHB的合成量减少,PHV和PH2MV的合成量增加,糖原的代谢量增加;低氧末磷的剩余量减少,硝态氮的累积增加.充水比分别为0.3,0.5和0.785的SBR-A,SBR-B和SBR-C系统中,总氮的去除率分别为89.4%,81.1%和46.4%,而磷的去除率分别为86.75%,97%和100%。     

A2/O工艺处理城镇污水的脱氮除磷性能研究

传统的污水脱氮除磷深度较浅,水体中仍含有较多的氮磷元素,为提高城镇污水处理中脱氮除磷的效率,该文以合肥市某污水处理厂二期工程污水处理为研究对象,对污水处理厂的整体污水处理工艺进行研究,提出多段A²/O污水处理工艺。结果表明,在采用多段A²/O污水处理工艺处理前后,污水总氮质量浓度、总磷质量浓度大幅度降低,满足表2中约束性出水指标要求;随着时间的增加,磷酸根的质量浓度呈对数增加的趋势,而释磷速率呈现线形增加后对数降低的趋势;随着时间的增加,好氧区和缺氧区的吸磷速率均呈现对数降低的趋势,且好氧区的吸磷速率比缺氧区的吸磷速率略大。     

海洋聚磷菌 Halomonas YSR-3 的除磷特性研究

用改变培养条件的方法对海洋聚磷菌Halomonas YSR-3 的生长和除磷特性进行了研究.研究结果表明,无磷培养时,该菌菌体不能生长;用磷酸钾盐作为磷源时,菌体生长较好,形成多聚磷酸盐的菌体比例较高;较适合YSR-3菌体生长和多聚磷酸盐形成的磷源是 KH2PO4,较适磷浓度为1 mmol/L.pH 的变化影响菌株的生长、多聚磷酸盐形成和除磷效果.pH 值为5时,菌体的数量几乎不增加(△OD480为0.013),体内多聚磷酸盐和培养基中磷含量变化不大;pH 值为6、7和8时,菌体生长良好(△OD480分别为1.529、1.539和1.497),95%以上的菌体内形成多聚磷酸盐,培养基中磷含量明显下降.YSR-3在不同培养基中除磷量和除磷率不同.在高磷培养基中除磷量为0.7 mmol/L(磷含量由1.84mmol/L降到1.14 mmol/L),除磷率为37.5%;在低磷培养基中除磷量为0.02 mmol/L(磷含量由0.028 mmol/L降到0.008 mmol/L),除磷率为72.2%.     

Transformation of phosphorus in intermittent aerated biofilter under aerobic continuous feeding with long backwashing intervals

A combined fixed-film system composed of anaerobic biofilter, aerobic biofilter, and intermittent aerated biofilter (IABF) is developed for enhanced biological phosphorus removal (EBPR) treating domestic wastewater. This work presents details on the performance of IABF under aerobic condition, where phosphorus-accumulating organisms are accumulated. Analysis on distribution of phosphorus in both the bulk and the biofilm indicates that the PAOs-rich biofilm is characterized by a high activity, a strong P capacity, and a good adaptability of fluctuations in aerobic continuous loading. An innovative means for P removal slows down accumulation of P in biofilm. As a result, removal of P-rich biomass is no longer a key limitation of EBPR performance in the biofilm system. Long backwashing interval is practicable in IABF under aerobic continuous feeding regime.     

HEAVY METALS REMOVAL IN A RAPID INFILTRATION SAND COLUMN

Sand filtration has been used as a cost-effective tertiary treatment process for sewage and wastewaters. However, little information is available on the performance of the process for heavy metals removal. In this project, the effect of a rapid infiltration sand filtration system on the removal of total organic carbon (TOC) phosphorus, Cd, Cu, Pb, and Zn from a mixed industrial and domestic wastewater was evaluated. To facilitate observation of the system behavior under varied conditions, the influent samples were also subjected to extreme pH values. Further studies were conducted to determine the effects of calcium carbonate addition for heavy metals precipitation prior to application onto the sand column. The results revealed that sand filtration was remarkably successful in removing phosphorus from wastewater under all conditions. The data further confirmed that in a sand filtration process, the mechanism of phosphorus removal was mainly due to chemical precipitation. Under neutral pH conditions, TOC, Cd, and Cu, were removed in the order of 20%, and Pb, and Zn were about 35-40% removed. Addition of a chemical precipitant such as calcium carbonate increased the pollutant removal to about 50%. At pH values below 2.4 and above 11.0, the TOC and all the metals showed an increase in concentration in passing through the sand column.     

Compartmentalizing anaerobic zone improves sludge settling property of enhanced biological phosphorus removal system under low sludge retention time

Abstract

The study investigated the effect of compartmentalization of anaerobic zone on sludge settling property in an enhanced biological phosphorus removal (EBPR) system. Continuous‐flow pilot‐plant experiments with synthetic influent were performed at varied anaerobic‐oxic volume ratios (V_an : V_o , 1 : 9 and 2 : 8), involving 5, 10 and 15 days of sludge retention times (SRTs). Experimental results indicated that, regardless of V_an : V_o and SRT, satisfactory removal of COD and phosphate were achieved during all test runs. However, extremely high sludge volume index (SVI) values were observed when there were 5 days of SRT. Further experiments with compartmentalization of anaerobic zone were therefore conducted to confirm the necessity of incorporating the kinetic selection mechanism of bulking control into an EBPR process operated at a low SRT. These results revealed that the two factors, V_an : V_o and anaerobic compartmentalization, had interaction with respect to sludge settling property in terms of SVI. When anaerobic retention time increased from 0.72hr to 1.36hr, compartmentalizing anaerobic zone significantly decreased the SVI value because of generating high COD concentration gradient and phosphate release in the anaerobic zone. This result implies that supplementing kinetic selection pressure of bulking control exhibits a critical influence on sludge settling when the EBPR process operates at a lower SRT.     

HEAVY METALS REMOVAL IN A RAPID INFILTRATION SAND COLUMN

ABSTRACT

Sand filtration has been used as a cost-effective tertiary treatment process for sewage and wastewaters. However, little information is available on the performance of the process for heavy metals removal. In this project, the effect of a rapid infiltration sand filtration system on the removal of total organic carbon (TOC) phosphorus, Cd, Cu, Pb, and Zn from a mixed industrial and domestic wastewater was evaluated. To facilitate observation of the system behavior under varied conditions, the influent samples were also subjected to extreme pH values. Further studies were conducted to determine the effects of calcium carbonate addition for heavy metals precipitation prior to application onto the sand column. The results revealed that sand filtration was remarkably successful in removing phosphorus from wastewater under all conditions. The data further confirmed that in a sand filtration process, the mechanism of phosphorus removal was mainly due to chemical precipitation. Under neutral pH conditions, TOC, Cd, and Cu, were removed in the order of 20%, and Pb, and Zn were about 35–40% removed. Addition of a chemical precipitant such as calcium carbonate increased the pollutant removal to about 50%. At pH values below 2.4 and above 11.0, the TOC and all the metals showed an increase in concentration in passing through the sand column.     

Application of a by-product of Lentinus edodes to the bioremediation of chromate contaminated water

The agricultural by-product of Lentinus edodes was used as a novel biosorbent for bioremediation of chromate contaminated waste water in the simulated experimental conditions. The contact time, particle size, biosorbent dosage and optimum pH range were investigated to optimize the sorption condition. The biosorption by the biomass was strongly affected by pH. At pH 1.0-2.5, all hexavalent chromium was diminished, either removed by the biosorbent or reduced to less toxic trivalent chromium even in very high concentration of 1000 mg/L. The adsorbed hexavalent chromium and reduced trivalent chromium were both linearly dependent on the initial chromium concentration. Most uptake of Cr occurred at pH around 4. The maximum uptake of chromium was 21.5 mg/g when simulated with Langmuir model, which showed the potential biosorption capacity of this biomaterial. The change of oxidation-reduction potential (ORP) during biosorption process revealed strong reduction ability of this biosorbent. Comparing analysis from Fourier transform infrared spectrums indicated that nitrogen oxide and carboxyl groups were increased after biosorption. The energy-dispersive X-ray microanalyzer revealed the mechanism of cation exchange during biosorption.     

Real-time control of oxic phase using pH (mV)-time profile in swine wastewater treatment

The feasibility of real-time control of the oxic phase using the pH (mV)-time profile in a sequencing batch reactor for swine wastewater treatment was evaluated, and the characteristics of the novel real-time control strategies were analyzed in two different concentrated wastewaters. The nitrogen break point (NBP) on the moving slope change (MSC) of the pH (mV) was designated as a real-time control point, and a pilot-scale sequencing batch reactor (18 m³) was designed to fulfill the objectives of the study. Successful real-time control using the developed control strategy was achieved despite the large variations in the influent strength and the loading rate per cycle. Indeed, complete and consistent removal of NH₄-N (100% removal) was achieved. There was a strong positive correlation (r² = 0.9789) between the loading rate and soluble total organic carbon (TOCs) removal, and a loading rate of 100 g/m³/cycle was found to be optimum for TOCs removal. Experimental data showed that the real-time control strategy using the MSC of the pH (mV)-time profile could be utilized successfully for the removal of nitrogen from swine wastewater. Furthermore, the pH (mV) was a more reliable real-time control parameter than the oxidation–reduction potential (ORP) for the control of the oxic phase. However, the nitrate knee point (NKP) appeared more consistently upon the completion of denitrification on the ORP-time profile than on the pH (mV)-time profile.     

Phosphorus removal performance of acid mine drainage from wastewater

Acid mine drainage (AMD) in Yunfu iron sulfide mine contain Fe(2+), Fe(3+), and Al(3+) up to 8000, 1700 and 1200 mg/L, respectively. Phosphorus removal from synthetic wastewater with 10mg/L of total phosphorus (TP) concentration and second municipal effluent with 3.5-4.0mg/L of TP concentration were conducted with the AMD by jar tests. Dosage of the AMD and initial pH of water are the two most important parameters affecting the performance of phosphorus removal of the AMD. The optimal phosphorus removal efficiency and residual iron ions (TFe) concentration are 97.0% and 3.0mg/L, respectively, at 1.61 Fe/P molar ratio and pH 8.03 for synthetic wastewater, and 92.1% and 0.32 mg/L, respectively, for second municipal effluent at 1.41 Fe/P molar ratio and pH 7.3. Resultant heavy metal concentration in effluents and precipitate was very low, and the risk of resultant heavy metal contamination was very small. The phosphorus removal performance of the AMD was much similar to that of ferric sulfate (FS) and polyferric sulfate (PFS), and better than that of FeSO(4). And residual TFe concentration in treated water arising from utilization of the AMD was similar to that of FeSO(4), and higher than that of FS and PFS. The AMD could be used as coagulant for phosphorus removal from wastewater directly due to the presence of Fe(2+), Fe(3+), and Al(3+) largely.     

利用茭白叶制备的吸附材料除磷性能研究

以农业废弃物茭白叶为原料,采用氯化亚铁盐溶液浸渍制备改性茭白叶生物吸附剂,并用扫描电镜研究了茭白叶改性前后的表面形貌变化,重点研究了被吸附溶液pH值、浸渍改性液的浓度、生物吸附剂粒度、吸附时间等因素对磷吸附能力的影响.研究结果表明,经12%FeCl2溶液浸渍制得的片状生物吸附剂在pH值5.5的NaH2PO4溶液中经30h吸附后,茭白叶纤维素的羟基与铁离子反应,使得改性后茭白叶生物吸附剂具有较强的吸附能力,其去磷能力最高可达5.02mg/g,吸附符合伪一级动力学模型.     

Preparation and characterization of ferric-impregnated granular ceramics (FGCs) for phosphorus removal from aqueous solution

In the present study, the ferric-impregnated granular ceramic (FGC) adsorbents were developed for the removal of phosphorus from aqueous solution. BET, SEM, and EDS were used to characterize the physical and chemical attributes (particle size, pore size and distribution, surface roughness, and chemical composition) of FGCs. Phosphorus adsorption characteristics were studied in a static batch system with respect to changes in contact time, initial phosphorus concentration, pH of solution, and temperature. The adsorption process was observed to follow a pseudo-first-order kinetic model, taking about 36 h to attain equilibrium. Phosphorus adsorption was found to be pH dependent and the maximum removal was obtained at pH 7.0–9.0. The experimental data denoted that the Langmuir isotherm model gave a more satisfactory fit for phosphorus removal than the Freundlich isotherm model. Results suggested that the novel adsorbent of FGCs had a good potential in remediation of phosphorus removal in aqueous solutions.     

Biosorption of nickel from protonated rice bran

In the present study biosorption technique, the accumulation of metals by biomass was used for the removal of nickel from aqueous medium. The rice bran in its acid treated (H(3)PO(4)) form was used as a low cost sorbent. The adsorption characteristics of nickel on protonated rice bran were evaluated as a function of pH, biosorbent size, biosorbent dosage, initial concentration of nickel and time. Within the tested pH range (pH 1-7), the protonated rice bran displayed more resistance to pH variation, retaining up to 102 mg/g of the nickel binding capacity at pH 6. Meanwhile, at lower pH values the uptake capacity decreased. The % age removal of nickel was maximum at 0.25 g of biosorbent dose and 0.25 mm biosorbent size. At the optimal conditions, metal ion uptake was increased as the initial metal ion concentration increased up to 100mg/L. Kinetic and isotherm experiments were carried out at the optimal pH 6.0 for nickel. The metal removal rate was rapid, with 57% of the total adsorption taking place within 15-30 min. The Freundlich and Langmuir models were used to describe the uptake of nickel on protonated rice bran. The Langmuir and Freundlich model parameters were evaluated. The equilibrium adsorption data was better fitted to Langmuir adsorption isotherm model. The adsorption followed pseudo second-order kinetic model. The thermodynamic assessment of the metal ion-rice bran biomass system indicated the feasibility and spontaneous nature of the process and DeltaG degrees values were evaluated as ranging from -22.82 to -24.04 kJ/mol for nickel sorption. The order of magnitude of the DeltaG degrees values indicated an ion-exchange physiochemical sorption process.