活性污泥反硝化除磷性能的影响因素研究

以富含反硝化聚磷菌的污水处理厂(采用厌氧+ Carrousel氧化沟工艺)活性污泥为研究对象,进行静态厌氧释磷及反硝化聚磷试验研究,探讨碳源、硝酸盐及温度等因素对活性污泥反硝化聚磷性能的影响.结果表明:污水处理厂进水COD控制在200 mg/L左右时,能够在满足厌氧段释磷所需碳源的同时,使缺氧段有较少的碳源残留;厌氧段硝酸盐氮浓度宜控制在10 mg/L以下,而缺氧段的硝酸盐氮浓度应控制在40 mg/L左右,且水温为25℃左右时有利于反硝化聚磷的发生.此外,因厌氧释磷转变为缺氧聚磷需要一定的过渡时间(0.5～2 h),因此应适当延长缺氧段的水力停留时间,以保证反硝化聚磷效果.     

反硝化聚磷菌的脱氮除磷特性研究

为研究反硝化聚磷菌的脱氮除磷特性,对接触氧化、SBR、A/O、A2/O和双污泥系统的活性污泥做了好氧吸磷和缺氧吸磷的静态烧杯试验,单独考察了双污泥系统的污泥在厌氧条件下以不同碳源为底物和在缺氧条件下以NO3-为电子受体的释/吸磷特性。结果表明,SBR、A2/O、双污泥系统的污泥在好氧和缺氧条件下均有很好的吸磷效果,其中双污泥系统污泥的缺氧吸磷速率和反硝化速率最大。而且在缺氧条件下,当NO3-充足时其浓度对吸磷效果影响不大,吸磷速率为7.52 mgPO43--P/(gMLVSS.h),反硝化速率为9.74 mgNOx--N/(gMLVSS.h)。在厌氧条件下,以蔗糖为碳源的释磷量最小,释磷速率亦最低,而以CH3COONa为碳源的释磷量和释磷速率均最大,释磷速率为4.2 mgPO43--P/(gMLVSS.h)。     

碳源种类对反硝化除磷系统运行状态的影响

在与生活污水试验系统作对比的情况下,采用连续运行方式研究了乙酸、丙酸、葡萄糖三种单碳源对反硝化除磷系统运行状态的影响。试验结果表明:①运行良好的反硝化除磷系统能在短时间内承受因碳源变化带来的冲击;3d后单碳源系统出现了厌氧释磷和出水磷浓度的波动;两周后,乙酸、丙酸系统逐渐恢复稳定,葡萄糖系统则逐渐失去反硝化吸磷能力。②乙酸能提高生物除磷效果,可以作为富集反硝化除磷菌(DPB)的有效碳源;丙酸虽然也可以提高生物除磷效果,但对反硝化除磷的促进作用不明显;葡萄糖的大量存在将使已成为优势菌群的PAOs和DPB逐渐被非聚磷菌取代。③乙酸碳源基质的污泥产率系数低于丙酸和葡萄糖的,葡萄糖碳源基质有利于获得更高的污泥产率。     

硝酸盐浓度对反硝化聚磷菌诱导的影响

通过控制缺氧段硝酸盐浓度,研究了反硝化聚磷菌的诱导方法及效果.批式试验表明,碳源浓度一定时,缺氧段硝酸盐消耗量与聚磷量呈线性关系,且与厌氧释磷量之比等于该线性关系式的斜率.在反硝化聚磷菌诱导过程中,按此比例调整缺氧段的硝酸盐浓度可很快达到良好的脱氮除磷效果,反硝化聚磷率＞95%,反硝化脱氮率＞96%.由同等条件下的缺氧与好氧最大聚磷速率可推知,诱导前反硝化聚磷菌占总聚磷菌的27.61%,诱导后则高达78.61%.     

丙酸/乙酸比值对反硝化除磷的影响

分别以丙酸、丙酸/乙酸(浓度比值为0.5、2)、乙酸为碳源,在SBR中采用厌氧/缺氧方式驯化富集反硝化聚磷菌(DPB),研究了丙酸/乙酸比值对反硝化除磷系统中有机物的降解、PO3-4-P的释放与吸收、NO-x-N浓度、PHB和糖原含量以及污泥中磷含量的影响.结果表明,随着丙酸/乙酸比值的提高,厌氧释磷量减少,厌氧末期的PHB含量降低,缺氧段聚磷菌的合成和代谢能力减弱,最终导致对PO3-4-P的去除率降低.因此,乙酸含量高的碳源更利于反硝化除磷的进行.     

污泥臭氧/水解酸化液对生物脱氮除磷的影响

污泥原位减量工艺为解决目前污水处理厂所面临的进水碳源不足、污泥产量巨大等问题提供了新思路。污泥微生物细胞的溶解和胞内物质的释放与利用成为其关键环节。然而常规污泥破解技术很难达到预期效果,为此将臭氧和水解酸化技术耦合,利用间歇试验重点考察了污泥经臭氧/水解酸化后回流对有机物降解、硝化、反硝化、厌氧释磷和好氧吸磷过程的影响。结果发现,剩余污泥溶解液可以作为反硝化碳源,有44.1%的COD被反硝化菌快速利用,平均比脱氮速率介于乙酸钠和甲醇之间;污泥溶解液也能被聚磷菌利用实现厌氧释磷,最大比释磷速率是乙酸钠的72.2%;污泥溶解液回流对有机物降解、硝化以及好氧吸磷过程均无影响。但由于曝气结束时仍有COD残留,因此需要控制其回流比例,以免难降解物质积累。     

反硝化聚磷工艺相关探讨

引言反硝化聚磷工艺是在厌氧/缺氧环境下利用以硝酸根作为电子受体的反硝化聚磷菌,通过它们厌氧释磷,缺氧存在硝酸盐情况下聚磷,并同时反硝化,达到同时利用同一细菌在同一阶段脱氮除磷的双重目的。相比传统的A2/O工艺具有节省能耗,减少运行费用,剩余污泥产量少等优点。     

厨余发酵液为外碳源的A/O-MBR脱氮除磷特性

利用厨余发酵液作为外碳源以改善A/O-MBR的脱氮除磷性能。结果表明:投加发酵液后反应器的脱氮除磷效果明显提高,出水NH+4-N、TN和PO3-4-P的平均浓度分别为0.72、7.25、1.78 mg/L,去除率分别达到96%、65%和85%以上。此外,厌氧污泥中的TP含量明显低于好氧污泥,而上清液中的PO3-4-P浓度高于好氧池,说明聚磷菌在厌氧条件下释磷,而在好氧条件下吸磷。释磷/吸磷批式试验进一步证实了在厌氧条件下主要进行释磷和反硝化过程,释磷速率达到5.66 mg/(g MLVSS·h),而在好氧条件下主要进行吸磷和硝化过程,吸磷速率和硝化速率分别为4.79、2.37 mg/(g MLVSS·h),较高的微生物活性有利于对污染物的去除。     

颗粒污泥的反硝化除磷研究

借助SBR反应器,采用厌氧/好氧/缺氧的运行方式,对富集的以反硝化聚磷菌（DNPAOs）为优势菌的活性污泥进行颗粒化培养,约35 d后得到了较成熟的颗粒污泥.考察了该颗粒污泥的脱氮除磷性能,结果表明：当以厌氧/缺氧方式运行时系统具有良好的反硝化除磷性能,缺氧结束时除磷率＞96%,对氨氮的去除率为95%左右;外加NO3^- -N的浓度对缺氧段的反硝化吸磷速率有一定影响;颗粒污泥中的DNPAOs可以利用内碳源进行反硝化吸磷,从而实现了同步脱氮除磷.     

不同城市污水处理厂反硝化除磷性能的比较研究

对采用不同工艺的3个城市污水处理厂的活性污泥进行了厌氧释磷、好氧聚磷及反硝化聚磷试验研究,以确定其反硝化除磷能力及差异性。3个污水处理厂采用的工艺分别为内设厌氧段的Carrousel氧化沟(A/O)、外设厌氧池的Carrousel氧化沟(A/C)和具有独立厌氧、缺氧及曝气池的A2/O工艺。结果表明,A/O工艺中活性污泥的释磷能力相对较强,A/C与A2/O工艺中活性污泥的释磷能力相当;A/C工艺中活性污泥的好氧聚磷和反硝化聚磷能力均优于其他两种工艺,好氧聚磷量和反硝化聚磷量分别为15.39和8.09 mgP/gVSS,活性污泥中存在数量可观的反硝化聚磷菌(DPB),反硝化聚磷菌与好氧聚磷菌的比例(DPB/PAO)为57.7%;A/O和A2/O工艺的活性污泥中同样存在DPB,但DPB/PAO值较低,分别为32%和27%。     

短程反硝化除磷系统的驯化及除磷特性研究

依据反硝化除磷(DBP)原理,采用批式试验,以城市污水为处理对象,研究了以NO_2~-为电子受体的反硝化除磷菌的筛选与富集,并对其反硝化除磷性能进行了考察.结果表明:NO_2~-对传统EBPR系统的抑制作用明显高于以NO_3~-为电子受体的反硝化除磷系统;对以NO_3~-为电子受体的反硝化除磷污泥用NO_2~-进行驯化,经过52个周期,缺氧吸磷量由0.3 mg/L升高到9.1mg/L,短程反硝化除磷系统驯化成熟;驯化成熟的短程反硝化除磷系统仍能以氧和NO_3~-作为电子受体进行吸磷并维持较高的吸磷速率,以亚硝酸盐为电子受体的除磷菌占总除磷菌的58.82%,说明短程反硝化除磷菌存在于传统除磷系统中,且能够很好地利用氧和硝酸盐为电子受体进行反硝化除磷.     

Phosphorus in industrial water

Phosphate in the waters used by industry is very rarely of any significance, since it occurs together with other ions which are normally at a far higher concentration: the removal of these other ions generally removes the phosphate content at the same time. Polyphosphates are very widely used in industry to avoid or alleviate the problems due to scale formation in boilers, heat exchange and cooling circuits, and more recently in desalination plants. For the removal of phosphates from waters, the existing industrial water treatment techniques can readily be adapted to achieve effective reduction or removal of the ion.     

Phosphorus in marine zooplankton

In the euphotic zone, phosphorus compounds dissolved in sea water are utilized by growing plants, many of which are subsequently eaten by herbivorous zooplankton and the dietary phosphorus invested partly in growth and egg production, partly released in insoluble form as faecal pellets and partly metabolized. The fraction metabolized is excreted back into the sea water mainly as inorganic phosphate, which is again available as a nutrient for the plants.Quantitative aspects of this cyclic process are discussed with particular reference to the Calanoid copepods, animals of central importance to the marine food web in several sea areas. Topics include: (1) laboratory and field investigations of the assimilation of dietary phosphorus and the efficiency of this process; (2) the rates at which zooplankton release soluble forms of phosphorus in relation to species, body size, food availability and season; (3) the importance of zooplankton in regenerating phosphorus compounds that may be used by the plant population; (4) the daily rations of phosphorus captured by zooplankton; (5) the total amounts and chemical forms of phosphorus in the animals; (6) growth of zooplankton and the use of N:P ratios in animals, diets and excretion products in estimations of gross growth efficiency interms of phosphorus; (7) future studies.     

反硝化聚磷菌菌剂种子液制备条件及除磷机理

为获取高效反硝化聚磷菌(DNPAOs)菌剂种子液以控制水体富营养化,从安徽省天长市污水处理厂氧化沟活性污泥中分离得到1株具有高效脱氮除磷功能的恶臭假单胞菌B8(Pseudomonas putida sp.)。利用多聚磷酸盐颗粒(Poly-P)染色得到具有高Poly-P含量的B8菌剂种子液。其适宜的培养条件为:pH6.5~7.0,温度30~32℃,溶解氧相当于70%~88%饱和溶解氧(摇床转速120~140r/min),培养时间15~20h。所得的反硝化聚磷菌种子液B8具有良好的同步反硝化除磷效果,对于污水厌氧/缺氧(A/A)处理,其聚磷率、硝酸盐氮去除率分别达到89.73%和53.48%,而经厌氧/好氧(A/O)处理磷去除率最高可达94.09%。通过B8胞外聚合物(EPS)提取与磷去除实验表明其对磷酸盐去除源于B8胞内的吸收,而非胞外的生物吸附。     

Phosphorus removal by activated algae

Phosphorus removal by the activated algae process was studied in laboratory scale under various conditions of hydraulic loading. Phosphorus removal ranged from 70% at 4 h hydraulic retention time, to 95% at 12 h hydraulic retention time. Chemical precipitation was found to be the predominant mechanism for phosphorus removal. An optical device for introducing light to the process was used which, based on theoretical consideration, significantly increases the efficiency of light utilization by algae cultures.     

Phosphorus models for eutrophic lakes

A model is developed for a highly eutrophic lake (White Lake, Michigan) which incorporates both the water and sediment systems and considers two forms of phosphorus—particulate and dissolved. Dynamic interactions of phosphorus between sediments and water are quantified by taking account particulate phosphorus sinking to the sediment-water interface and diffusion of dissolved phosphorus across the interface. Other model mechanisms include vertical eddy diffusion in the water; phosphorus transformation between the particulate form and the dissolved form in both the water and the sediment, diffusion of phosphorus in the interstitial water, and sedimentation in the sediments.

Extensive field data have been used to determine the coefficients and parameters defined in the model formulations. Close agreement between the model calculations and the observed data is obtained, especially for the upper layers of the sediment. Sensitivity analysis for the model further substantiates the model calculations. It is found that two separate forms of phosphorus are necessary to gain detailed insight into the dynamics of phosphorus cycling in White Lake. The model also explains significant releases of phosphorus during anaerobic periods from the sediment to the hypolimnion of White Lake in summer. The general applicability of the model to lakes having different degrees of eutrophication must be determined by an examination and analysis of data from other systems.     

Phosphorus in primary aquatic plants

As with other organisms, phosphorus is an essential element for aquatic plants. It is a component of molecules such as the nucleic acids and adenosine triphosphate (ATP) involved in the vital processes of enzyme synthesis and energy transfer and its compounds play a basic role in the mechanisms of photosynthesis by which these plants act as the primary producers of organic matter in aquatic environments. In the plant it is about eighth in order of abundance among the elements whereas in cosmic abundance it lies fifteenth and among the nutrient elements dissolved in natural waters it is often in relatively shortest supply. These facts lead to the conclusion that the concentration of available phosphorus compounds controls the growth of plants in aquatic habitats. This generalization has a certain validity, as Vollenweider (1968), for example, has shown, but because of the complexities in the utilization and metabolism of phosphorus by plants apparent exceptions are frequent and those who have sought to controvert it have had no difficulty in finding data to support their case (see Schindler, 1971).In this review attention will be concentrated on the relations of algal growth to phosphorus supply. This seems justified because not only are algae the predominant plants in aquatic habitats but little research appears to have been carried out specifically on phosphorus uptake and metabolism in higher aquatic plants. Presumably the latter are generally similar to terrestrial flowering plants in their relations to phosphorus and the information given in works on plant physiology applies. No attempt can be made to review completely the literature on the phosphorus metabolism of algae. For further references the reviews of Kuhl (1962, 1968) should be consulted.     

污泥减量化工艺:HA-A/A-MCO的除磷性能及磷回收

针对污泥减量技术中对氮、磷去除能力低的问题,开发了一种具有强化脱氮除磷功能、污泥减量化的HA-A/A-MCO工艺,其通过回流释磷污泥的水解酸化来刺激磷的厌氧释放并辅以外排富磷污水进行化学固定的方式除磷.研究发现:当进入水解酸化池的厌氧释磷污泥量为进水量的2%时,水解产生的VFA导致释磷量达57 mg/L,聚磷菌的生长得到促进而聚糖菌则受到抑制;当控制侧流除磷液量为进水量的13%、化学除磷池出水磷为5 mg/L时,系统处理出水TP<0.5 mg/L;提高厌氧释磷浓度并控制化学除磷池的出水磷浓度为5 mg/L,可以提高化学药剂利用率、减少药剂用量并提高化学污泥的含磷量,HA-A/A-MCO系统产生的化学污泥含磷率高达18%,接近纯含磷化合物的含磷率,可直接用作生产磷肥的原料.     

利用反硝化聚磷菌实现城市污水处理同步高效除磷、脱氮工艺技术的研究

论述了当前污水生物脱氮除磷技术与工艺的研究现状及存在问题,介绍了建设部课题"利用反硝化聚磷菌实现城市污水处理同步高效除磷、脱氮工艺技术的研究"的研究意义、研究目的及项目特色,对主要的研究结果和应用领域进行了阐述。     

化学除磷比值对低碳源污水脱氮除磷的影响

为解决低碳源城市污水高效脱氮除磷及磷回收问题,开发了侧流A2O工艺,通过抽取不同量的厌氧池末端富磷上清液至化学除磷池,来研究系统的脱氮除磷效果及磷回收情况。结果表明,在无需增加额外碳源,进水COD为136～168 mg/L、NH3-N为32～40 mg/L、TN为36～45mg/L、TP为6～8 mg/L的条件下,当化学除磷比(富磷上清液抽取量与进水量之比)为10%～20%时,对TN和TP的平均去除率分别可达到95.7%、84%,其中,当化学除磷比为15%时,出水TP浓度可降至0.5 mg/L以下,出水水质达到《城镇污水处理厂污染物排放标准(》GB 18918—2002)的一级A标准;同时,回收磷量可达进水磷量的23%～29%,既实现了磷的可持续发展,又增加了污水厂的经济效益。