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.     

产α-淀粉酶菌株液体培养条件的探讨

目的是探讨在液体培养条件下枯草芽胞杆菌(B.subtilis HY-02)降解淀粉的影响因素。方法是设0、0.5%、1%、1.75%四种淀粉浓度的培养基,接种细菌后,在32℃的温箱、水浴、振荡三种条件下培养,连续检测α-淀粉酶活性及淀粉浓度。结果为温箱、水浴培养:96h后,1%淀粉瓶α-淀粉酶活性、分解淀粉最明显,1.75%淀粉瓶存在抑制酶活性的现象。振荡培养:1.75%淀粉瓶优于其他组。结论是初始淀粉浓度、培养方式对枯草芽胞杆菌α-淀粉酶活性影响较大,也直接影响了淀粉的分解。     

氨基淀粉絮凝剂合成工艺

以玉米淀粉为原料，以环氧氯丙烷(ECH)作交联剂，合成高交联淀粉(CS)；以HC1O4作引发剂，以ECH作醚化剂，合成中间产物3-氯-2-羟基丙烯基交联淀粉(CHCS)，在碱性条件下再与乙二胺反应，得到对重金属离子具有螯合能力的氨基淀粉(CAS)。最佳醚化条件：CS含水质量分数为7．0％，ECH与CS的摩尔比为2．5：1，HC104与CS的摩尔比为0．03：1，反应时间为8h，反应温度为95℃。以该法制得的CAS对废水中铜离子的去除能力为78．5mg／g。     

Water vapor permeability of biodegradable polymers

The water vapor transmission rates (WVTR) of several biodegradable polymers were evaluated to determine their suitability as water-resistant coatings and to understand WVTR better in terms of polymer structure. Values of WVTR at 25‡C ranged from 13 to 2900 g/m² /day and increased in the order PHBV PLA (cryst.) PLA (amorph.) PCL Bionolle BAK 1095 CAP CA. Values of WVTR were positively correlated with higher polymer solubility parameters, lower crystallinities, and higher free volumes. Although the WVTR of biodegradable polymers are much higher than those of good barrier materials such as low-density polyethylene, they are sufficient for short-term (hours to days) protection of polysaccharide-based materials against water. Product names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable.     

Pressure- volume- temperature relationships of soy protein isolate/starch plastic

The use of pressure-volume-temperature (PVT) studies in processing of a biodegradable plastic composition made from soy protein isolate and corn starch is described. The ability of PVT measurements to predict the combined effects of pressure, volume, and temperature effects is demonstrated. The results show that the PVT relations of the plastic can be predicted by using a regression analysis similar to the Tait equations of state. A change in slope of the PVT curves was observed at around 80‡C, which is ascribed to the glass-transition process of the plastic. Evidence of onset of thermal degradation of the plastic was observed at ca. 160‡C under 0 to 200 MPa isobaric pressure. This thermal degradation precluded determination of the crystal melting point of the plastic.     

Polymeric Complexes from Casein and Starch Phosphate: Characteristics and Enzyme Susceptibility

Novel biodegradable materials were prepared from potato starch enriched in phosphato moieties (DS 0.018 and 0.033) and casein in defatted milk. The components were blended in proportions providing starch: casein ratios of 2:1, 1:1, and 1:2 and were then precipitated with hydrochloric acid. Aqueous solubility, water-binding capacity, infrared spectra, and thermal analysis (thermogravimetry[7] and differential thermogravimetry of the precipitates revealed that they were not simple physical mixtures of the components. The components interacted with one another electrostatically with involvement of the phosphate groups of starch and the peptide bond of casein, as documented by infrared spectra. Because of insolubility in 7 M aqueous urea solution, they might also be considered as complexes in which the components were chemically bound.     

常温条件下2种厌氧折流板反应器处理淀粉废水的启动实验

为了研究厌氧折流板反应器在常温下的启动情况,在22.5～30.2℃条件下,对不加填料的5隔室厌氧折流板反应器和加填料的4隔室复合式厌氧折流板反应器同步进行了启动实验。实验用水为高浓度淀粉废水,两反应器采用相同的启动策略,即梯度增加进水COD浓度与降低水力停留时间相结合的方式。两反应器有效容积均为47.8 L,启动初始负荷为0.6 kg COD/(m3.d),逐渐增加到10 kg COD/(m3.d)。实验表明,经过6个阶段87 d的运行,反应器启动完成,并成功培养出颗粒污泥,两反应器对COD的去除率都能达到85%以上。在启动过程中两反应器对COD的去除效率相近。     

Anaerobic tapered fluidized bed reactor for starch wastewater treatment and modeling using multilayer perceptron neural network

Anaerobic treatability of synthetic sago wastewater was investigated in a laboratory anaerobic tapered fluidized bed reactor(ATFBR) with a mesoporous granular activated carbon(GAC)as a support material.The experimental protocol was defined to examine the effect of the maximum organic loading rate(OLR),hydraulic retention time(HRT),the efficiency of the reactor and to report on its steady- state performance.The reactor was subjected to a steady-state operation over a range of OLR up to 85.44 kg COD/(m~3.d).The COD removal efficiency was found to be 92% in the reactor while the biogas produced in the digester reached 25.38 m~3/(m~3·d) of the reactor. With the increase of OLR from 83.7 kg COD/(m~3.d),the COD removal efficiency decreased.Also an artificial neural network(ANN) model using multilayer perceptron(MLP)has been developed for a system of two input variable and five output dependent variables. For the training of the input-output data,the experimental values obtained have been used.The output parameters predicted have been found to be much closer to the corresponding experimental ones and the model was validated for 30% of the untrained data.The mean square error(MSE)was found to be only 0.0146.     

无机-有机复合絮凝剂PST处理印染废水效果研究

以模拟印染废水和实际印染废水为实验对象,检验了一种新合成有机-无机复合絮凝剂(PST)的絮凝效果。结果表明,PST具有良好的絮凝性能。在受试条件下,絮凝效果与絮凝剂投加量、染料浓度有较大相关性。废水的pH值应用范围较宽;搅拌时间对COD去除率和脱色率没有显著影响。采用PST处理广东省高明市某印染厂的印染废水后,COD去除率为75.16%,脱色率为76.18%,处理效果良好,处理成本明显低于目前市场上普遍使用的聚铝等絮凝剂。     

新型材料淀粉微球对Cu2＋、Cr3＋和Pb2＋的吸附机理研究

以可溶性淀粉为原料,在反相悬浮体系中合成N,N′-亚甲基双丙烯酰胺交联淀粉微球为载体,研究了新型吸附材料淀粉微球（cross-linked starch microsphere,CSMs）对Mn＋（Cu2＋、Cr3＋、Pb2＋）的静态吸附行为。利用扫描电镜、X射线衍射仪和红外光谱仪对微球及其吸附产物进行表征,分析讨论了3种金属原子结构,研究了吸附机理。结果表明：308K时,Cu2＋、Pb2＋和Cr3＋的饱和吸附量分别是2.43、0.30和0.27 mmol/g,CSMs对Cu2＋离子吸附能力最强,并且其通过物理吸附、配位吸附方式吸附Mn＋,并得出引起微球吸附能力大小可能与金属离子电荷、离子半径和外层电子排布的差异因素有关。