Kinetic analysis of anaerobic phosphorus release during biological phosphorus removal process

Enhanced biological phosphorus removal (EBPR) is a commonly used and sustainable method for phosphorus removal from wastewater. Poly-β-hydroxybutyrate (PHB), polyphosphate, and glycogen are three kinds of intracellular storage polymers in phosphorus accumulation organisms. The variation of these polymers under different conditions has an apparent influence on anaerobic phosphorus release, which is very important for controlling the performance of EBPR. To obtain the mechanism and kinetic character of anaerobic phosphorus release, a series of batch experiments were performed using the excessively aerated sludge from the aerobic unit of the biological phosphorus removal system in this study. The results showed that the volatile suspended solid (VSS) had an increasing trend, while the mixed liquid suspended sludge (MLSS) and ashes were reduced during the anaerobic phosphorus release process. The interruption of anaerobic HAc-uptake and phosphorus-release occurs when the glycogen in the phosphorus-accumulating-organisms is exhausted. Under the condition of lower initial HAc-COD, HAc became the limiting factor after some time for anaerobic HAc uptake. Under the condition of higher initial HAc-COD, HAc uptake was stopped because of the depletion of glycogen in the microorganisms. The mean ratio of Δρ _P/Δρ _PHB, Δρ _GLY/Δρ _PHB, Δρ _P/ΔCOD, was 0.48, 0.50, 0.44, and 0.92, respectively, which was nearly the same as the theoretical value. The calibrated kinetic parameters of the HAc-uptake and phosphorus-release model were evaluated as follows: Q _HAc,max was 164 mg/(g · h), Q _P,max was 69.9 mg/(g · h), K _gly was 0.005, and KCOD was 3 mg/L. An apparently linear correlation was observed between the ratio of Δρ _P/ΔCOD and pH of the solution, and the equation between them was obtained in this study. Translated from Acta Scientiae Circumstantiae, 2005, 25(9), 1164–1169 [译自: 环境科学学报]     

废水生物除磷机理研究--Ⅰ.活性污泥混合液中微生物内聚磷酸盐含量变化特点

提出了活性污泥混合液中微生物内聚磷酸盐含量的测定方法.分别考察了常温好氧、厌氧条件下,废水生物除磷试验装置内活性污泥混合液中微生物内聚磷酸盐含量随时间变化的特点.结果表明,好氧条件下,微生物的内聚磷酸盐含量随时间的延长呈线性关系增加;厌氧条件下,聚磷酸盐含量随时间的延长呈线性关系减少.     

生物强化除磷机理的探讨

对生物强化除磷(EBPR)的机理进行了探讨。首先介绍了聚磷菌胞内贮存物(聚磷、PHAs和糖原)的性质和功能,然后对这些贮存物在厌氧和好氧(缺氧)情况下的反应加以分析。旨在从能量转化的角度对EBPR过程加以阐述,加深对生物除磷机理的认识。     

pH对低温除磷微生物种群与聚磷菌代谢的影响

在5°C条件下通过运行SBR生物除磷反应器和静态实验考察pH对低温生物除磷系统的影响。pH不仅影响生物除磷反应器的性能,而且也会影响生物除磷系统的微生物种群结构。在pH为6的条件下长期运行的生物除磷系统中聚糖菌大量存在;而在中性(pH=7)和弱碱性(pH=8)条件下,聚磷菌在活性污泥中占有优势地位。静态实验结果表明,当pH在6⁸.5之间变化时,聚磷污泥的厌氧释磷能力随pH的升高而提高。pH在68.5之间变化时,聚磷污泥的厌氧释磷能力随pH的升高而提高。pH在6⁸之间变化时,乙酸吸收和PHB的合成能力随着pH升高而加强,当pH升高到8.5时,PHB合成能力下降,从而抑制了好氧段磷酸盐的吸收。pH为8时,生物除磷系统实现了充分的释磷和吸磷,并取得了最好的除磷效果。     

太湖草型区与藻型区沉积物中聚磷菌富集试验研究

采用序批式反应器(SBR)小型反应装置,以葡萄糖和丙酸为碳源,在厌氧/好氧条件下,对太湖草型区和藻型区的沉积物进行聚磷菌富集培养。探讨了太湖草型区和藻型区沉积物中聚磷菌的存在性和差异性。试验结果表明,通过实验室模拟条件培养,发现太湖沉积物存在聚磷细菌。两种碳源培养的草型区沉积物厌氧释磷量高于藻型区。以葡萄糖为碳源培养的草型区和藻型区沉积物厌氧释磷现象微弱,好氧磷的超量吸收现象比活性污泥弱,对PO34--P的平均去除率分别为34.95%、38.17%。而在以丙酸为碳源的系统中,有着明显的厌氧释磷和好氧摄磷现象,对PO34--P的平均去除率分别为41.27%、51.35%。     

Bioabsorbable soy protein plastic composites: Effect of polyphosphate fillers on water absorption and mechanical properties

The use of synthetic and natural bioabsorbable plastics has been severely limited due to their low stiffness and strength properties as well as their strong tendency to absorb moisture. This research focused on the development of bioabsorbable polyphosphate filler/soy protein plastic composites with enhanced stiffness, strength, and water resistance. Bioabsorbable polyphosphate fillers, biodegradable soy protein isolate, plasticizer, and adhesion promoter were homogenized and compression-molded. Physical, mechanical, and water absorption testing was performed on the molded specimens. Results showed improvements in stiffness, strength, and water resistance with increasing polyphosphate filler content up to 20% by weight. Application of a coupling agent produced further mechanical property enhancements and a dramatic improvement in water resistance, interpreted by an interfacial chemical bonding model. Examination of the fracture surfaces of the materials revealed that the addition of the polyphosphate fillers changed the failure mode from brittle to pseudo-ductile. These results suggest that these materials are suitable for many load-bearing applications in both humid and dry environments where current soy protein plastics are not usable.     

Monitoring microbial community structure and succession of an A/O SBR during start-up period using PCR-DGGE

Polymerase chain reaction (PCR) - denaturing gradient gel electrophoresis (DGGE) protocol was employed for revealing microbial community structure and succession in a sequential anaerobic and aerobic reactor performing enhanced biological phosphorus removal (EBPR) during start-up period.High phosphorus removal was achieved after 15 d.On day 30, phosphorus removal efficiency reached to 83.2% and the start-up was finished.DGGE profiles of periodical sludge samples showed that dominant microbial species were 19 OTUs (operational taxonomy unit ).Unweighted pair-group method using Arithmetic averages (UPGMA clustering analysis revealed that rapid community succession correlated to lower phosphorus removal rate and higher phosphorus removal efficiency reflected on steady community structure.Sequencing results indicated that determined sequences (12 OTUs) belonged to proteobacterium, Actinobacteria, Gemmatimonadales and unaffiliate group.Proteobacterium, Tetrasphaera elongate and Gemmatimonas aurantiaca may act important roles in phosphorus removal.With little amount as known glycogen accumulating organisms, Candidatus Competibacter phosphatis still at accumulating-phase had limited influence on microbial community structure.When climax community was obtained, dominant microbes were 14 OTUs.Microbes in a large amount were uncultured bacterium, Thauera sp., uncultured γ-Proteobacterium and Tetrasphaera elongata.     

单一好氧环境强化生物除磷诱导及影响因素研究

为了加深对聚磷菌(Phosphate Accumulating Organism,PAOs)代谢多样性及代谢机理的认识,采用序批式反应器(Sequencing Batch Reactor,SBR),研究了PAOs单一好氧生物除磷能力的诱导过程,以及好氧时间、静置时间对单一好氧生物除磷效率的影响。结果表明,PAOs单一好氧环境生物除磷能力的诱导很快完成,SBR反应器运行周期内生物除磷过程分为饱食期与饥饿期,其中,饱食期水溶液中COD降解速度很快,磷酸盐质量浓度略有升高,PAOs体内聚-β-羟基丁酸(Poly-β-hydroxybutyrate,PHB)质量比增加,聚磷质量比降低;饥饿期水溶液中磷酸盐质量浓度持续下降,聚磷菌体内PHB质量比减小,聚磷质量比增加。聚磷菌在单一好氧环境条件下的除磷能力不能长期保持,只有保证足够的好氧时间及静置时间,才能取得高效的单一好氧环境除磷效果。     

镍对活性污泥生物除磷的影响及其机理

以实际生活污水为研究对象,在序批式活性污泥反应器中探究了Ni2+对活性污泥形态及生物除磷性能的影响。实验结果表明,Ni2+能够抑制生物除磷,当Ni2+质量浓度由0 mg/L增加至10.0 mg/L时,PO43--P去除率由93%下降至12%。机理研究结果表明：Ni2+能抑制聚磷微生物的厌氧释磷和好氧吸磷,并能抑制内聚物聚羟基烷酸酯（PHA）的合成;当Ni2+质量浓度为10.0 mg/L时,PHA的最大含量仅为2.4 mmol/g （以单位质量挥发性悬浮物所含PHA中C的物质的量计）,远低于空白组中PHA的含量。此外,Ni2+还对微生物群落的组成产生影响,并促进活性污泥中聚糖微生物的增殖。     

硝酸盐作为生物除磷电子受体的研究

研究了以硝酸盐作为电子受体进行生物除磷的可能性,并比较了硝酸盐和氧作为电子受体的差异.结果表明:聚磷菌能以硝酸盐作为电子受体替代氧进行生物除磷,但若存在有机碳源会抑制缺氧段磷的吸收.缺氧条件下磷的摄取速率与硝酸盐的质量浓度有关,浓度越高速度越快.硝酸盐的连续稳定加入有利于磷的去除.与以氧为电子受体的系统相比硝酸盐系统利用PHA的效率低,缺氧系统中去除磷和消耗PHA的比例为0.63,比好氧系统中的0.83低24%;缺氧时每摩尔电子转移所吸收的磷为0.14 mol,比氧为电子受体时的0.23 mol低39.1%.