C.I.活性黄145的生物降解特性研究

文章主要研究在厌氧、好氧、厌氧/好氧条件下,通过采用活性污泥法生物降解活性染料C.I.活性黄145,从而了解该染料生物降解的特性。研究结果表明,在无外加碳源,染料浓度100 mg/L条件下,厌氧、好氧、厌氧/好氧条件下染料去除率均低于9.1%,而在外加碳源之后染料去除率明显升高,厌氧条件下染料去除率为90%。厌氧条件下能够处理更高浓度染料废水,染料浓度700 mg/L,去除率50%;好氧条件下染料浓度50~200 mg/L,染料去除率66%~12.7%;厌氧/好氧时染料去除率在厌氧段高。紫外-可见全波段扫描可知,在厌氧条件下染料在224 nm、256 nm、289 nm、416 nm的特征吸收峰或是降低或是消失。     

脂肪醇聚氧乙烯醚的厌氧与好氧生物降解性

以脂肪醇聚氧乙烯醚(AEO)为目标污染物，在等同条件下做厌氧消化污泥和好氧活性污泥对其生物降解性能的对比实验，得出了同一系列AEO分子中聚氧乙烯基与整个分子的降解难易程度的关系。表明：①污泥会对AEO分子产生吸附一脱附作用而出现假降解率，克服假降解率的干扰是准确测定AEO生物降解性的关键因素；②厌氧和好氧条件下，AEO均可降解，但厌氧降解要稍优于好氧降解；③AEO中聚氧乙烯基的单元数(n)是影响其生物降解的重要因素，相同碳链的直链烷基，生物降解率随n的增加而明显降低。     

醇醚糖苷厌氧生物降解性能及降解机理研究

参考GB/T 27857-2011有机物厌氧降解试验方法,在实验室条件下模拟厌氧环境,采用蒽酮法和TOC法分别研究了醇醚糖苷(AEG)的初级和最终生物降解性能。结果表明,即使AEG的起始质量浓度达到100 mg/L,其初级厌氧生物降解率仍然能够达到90%以上;当起始质量浓度为40 mg/L时,其最终厌氧生物降解率为88.5%。最后采用气-质联用仪对AEG的厌氧生物降解机理进行探讨发现:AEG首先经历糖苷醚键断裂,生成葡萄糖和AEO;之后AEO从末端EO链开始降解形成醇,最后转化为CO_2、CH_4和水等。     

PBAT/PLA薄膜在受控堆肥条件下的生物降解性能

为了快速检测聚己二酸—对苯二甲酸丁二醇酯/聚乳酸(PBAT/PLA)薄膜的生物降解性能,参考GB/T 19277.1—2011的检测方法,针对堆肥水分含量对实验进行了优化,研究了薄膜在受控堆肥条件下的最终需氧生物分解能力。结果表明,45%的含水量最有利于堆肥降解实验的进行,以腐熟堆肥为接种物建立的测试方法满足标准要求,所测试薄膜的最终生物分解率和相对生物分解率均大于90%,可完全降解。堆肥实验过程中薄膜的累积二氧化碳(CO₂)释放量、生物分解率、相对生物分解率随时间的变化情况一致,随时间变化先增大后减小,最后趋于稳定,呈S型曲线。“迟滞—生物分解—平稳”三阶段的表现与微生物的生命活动有关。     

酸性染料黑10B的生物降解特性研究

在好氧、厌氧和兼性交替条件下,采用活性污泥系统生物处理酸性染料,研究染料酸性黑10B在有氧或者厌氧状态下的生物降解特性以及在不同染料浓度和不同生物化学需氧量(COD)条件下对其降解特性的影响,并进行全波段扫描和气相色谱-质谱联用(GC-MS),初步探讨了该染料的生物降解过程。结果表明,染料黑10B在厌氧条件下降解效率最高,兼性条件下次之,好氧条件下最低。随着染料黑10B浓度的增加,反应器中COD的去除率逐渐降低。而碳源的投加量也对酸性黑10B的生物降解起到重要的作用。全波段扫描和GC-MS测定结果显示,染料黑10B经过生物降解作用后,发色基团得到降解,染料黑10B生物降解中间产物有苯胺、对苯二胺、对硝基苯胺,这些中间产物对应的停留时间分别是10.168、15.875、21.747 min。     

PLA在受控堆肥条件下的生物降解行为研究

依据ISO 14855的检测方法,研究了聚乳酸(PLA)在受控堆肥条件下的生物降解性能,结果表明:PLA具有良好的生物降解性。在培养土提取液中,以蛋白酶K对PLA膜进行降解,显微镜观察发现,PLA膜表面逐渐被蛋白酶侵蚀;红外光谱研究表明,PLA膜在降解前后的分子结构没有发生很大变化。     

吸附-生物降解法处理含挥发性有机物废水

采用吸附-生物降解法处理含碳氢溶剂挥发性有机物(VOCs)的水洗废水,研究了废水中挥发性有机成分的非稳性,考察了2种活性污泥(厌氧、好氧污泥)对废水中挥发性有机物的吸附性能,探讨了厌氧-好氧组合工艺对水洗废水的降解效能,分析了处理工艺的运行效果.结果表明,水洗废水中的VOCs易再次挥发,曝气状态下VOCs的最大挥发率为...     

生物法降解EDTA废水及其脱氮特性的研究

采用好氧反硝化菌群体系,通过改变共基质及pH值,在好氧条件下研究乙二胺四乙酸(EDTA)的生物降解特性,以及在EDTA存在条件下该体系的脱氮性能。试验结果表明,该菌群能够具有同时反硝化和降解EDTA的作用;单基质条件下EDTA难以生物降解,共基质可以促进EDTA的降解。其中,乙酸钠作为共基质经过7dEDTA降解83.24%,同时具有很好的反硝化效果;以葡萄糖作为共基质7dEDTA降解68%,但存在亚硝酸盐累积现象。酸性条件下对EDTA的生物降解有抑制作用,中性至碱性条件下EDTA降解效果较好,在pH值为7～9范围内,pH值对EDTA生物降解影响作用不大。     

染料分散大红S-BWFL生物降解特性研究

在好氧、厌氧、厌氧/好氧条件下,采用活性污泥法降解染料分散大红S-BWFL。实验结果表明分散大红S-BWFL在厌氧条件下降解效率最高,厌氧/好氧交替条件次之,好氧条件下降解效率最低。进水染料浓度100 mg/L时,染料12 h去除率最高为94.45%;随着染料浓度的增加,微生物对染料的降解效率逐渐下降,进水染料浓度500 mg/L时,染料12 h去除率最高为75.03%;分散大红S-BWFL降解最佳初始p H为8。GC-MS测得分散大红S-BWFL生物降解中间产物有对硝基苯胺、邻苯二甲酸单(2-乙基己基)酯和对硝基苯甲醚。     

改性聚乳酸材料的堆肥降解性能研究

依据GB/T 19277.1—2011测试方法,研究了丙烯腈-丁二烯-苯乙烯(ABS)改性聚乳酸(PLA)材料在受控堆肥条件下的生物降解性能。结果表明:PLA含量为80%以上的PLA/ABS共混材料具有较好的生物降解性能,且经堆肥降解试验后的培养土的挥发性固体含量、pH值与试验前接近。     

PPC/PBAT生物降解材料热性能和力学性能的研究

采用聚对苯二甲酸丁二醇酯-己二酸丁二醇酯(PBAT)对聚甲基乙撑碳酸酯(PPC)进行共混改性,对共混物进行了性能分析,并对PPC纯料与纤维素进行受控堆肥条件下最终需氧生物分解和崩解能力测试。结果表明:相同时间内PPC的生物分解速率要低于纤维素的生物分解速率;120 d内纤维素最大生物分解率为90%,PPC最大生物分解率约为63%;当PBAT的加入量为20%时,PPC的玻璃化转变温度提高3.55℃,失重率5%、50%和90%时的温度分别最高提高3.61℃、42.73℃和70.21℃;当PBAT含量为40%时,共混片材的拉伸强度最高提高了236.4%。     

Toxicological evaluation for bioremediation processes of TNT-contaminated soil by Salmonella mutagenicity assay

This research was performed to evaluate the toxicity for composting and slurry phase bioreactor processes of TNT (2,4,6-trinitrotoluene)-contaminated soils by Salmonella mutagenicity assay. For composting, the percentage reductions of final composts in strain TA98 and TA100 with S9 metabolic activation were 90.3?C93.7% and 96.7?C97.5%, respectively. For slurry phase bioreactor processes, the percentage reductions of final residuals in strain TA98 and TA100 with S9 metabolic activation were 95.0% and 99.1% for anaerobic, 96.2% and 99.2% for anaerobic/aerobic, and 96.6 and 97.4% for anaerobic treatment. Slurry phase treatment showed higher mutagenicity reduction than composting. It was implied that slurry phase treatment was a more effective process than composting in reducing toxicity. This research has the advantage of speed and ease of performance in comparison to testing of other higher life forms due to the shorter life cycles of microorganisms.     

受控堆肥条件下可降解材料最终需氧生物分解能力测定的不确定度评定研究

基于可降解塑料的降解性能测试周期长、影响因素多导致其不确定度评定的过程较为复杂的原因，对受控堆肥条件下材料最终需氧生物分解百分率（D_t）开展了不确定度评定，并根据各不确定度分量的合成方法，对其进行归一化及可视化处理，得到D_t的主要不确定度分量为f_{试验组重复性}、f_{空白组重复性}、碳原子摩尔质量（M_C）位数修约、f_TC重复性和m_TC。通过对试验进行优化后的结果表明，使D_t的不确定度分量集中在f_{试验组重复性}、f_{空白组重复性}和f_TC重复性3项A类标准不确定度上，其他的不确定度分量由于占比较小，均可忽略；简化后D_t的标准不确定度，只需要通过3项A类标准不确定度评定就能快速计算得到，省去了需要根据试验周期计算每天试验所产生的不确定度分量；简化计算得到的结果包含了90 %以上的经完整计算得到u_c（D_t），为可降解塑料降解性能测试的不确定度评定提供了思路及范例。     

Integrated anaerobic/aerobic biodegradation in an internal airlift loop reactor for phenol wastewater treatment

Anaerobic and aerobic biodegradation were integrated in an internal airlift loop reactor (IALR) by adding porous microbial carriers. In this bioreactor, aerobic activated sludge was suspended in the liquid bulk, while the anaerobic microbes were attached within the core of carriers. The integrated IALR was applied to the treatment of synthetic phenol wastewater. After 50 days’ acclimation according to co-substance strategy, the influent COD decreased from 3,700 mg/L to 400 mg/L (phenol removal rate was over 99%) with the residence time of 24 h. High performance could be achieved under the operation condition of superficial gas flow rate higher than 0.07 cm/s, temperature beyond 15°C and the microbial carrier volume fraction larger than 5%. Integration of anaerobic/aerobic biodegradation in IALR enhanced the synergetic effects between aerobic and anaerobic degradation; therefore, it has great potential in the treatment of phenol wastewater and other wastewater containing hard biodegradable organics.     

厌氧/好氧生物流化床耦合处理垃圾渗滤液的新工艺研究

采用厌氧/好氧生物流化床耦合工艺处理垃圾渗滤液。探索了厌氧/好氧的耦合及各种工艺操作条件对垃圾渗滤液生物降解效率的影响,并对其影响机理进行了初步的探讨。结果表明,经过高效厌氧流化床的处理, 垃圾渗滤液的可生化性可提高49.1%。CODCr/NH4+-N比值对渗滤液好氧生物降解性能有较显著的影响,适宜的CODCr/NH4+-N比值应控制在7.6左右。当进水CODCr及NH4+-N浓度分别为5000mgL-1、280mgL-1左右时,系统出水主要指标达到GB16889-1997一级排放标准。当系统受到短时间(12h左右)超过正常运行负荷约3倍的负荷冲击时,能在4d左右的时间内恢复正常。本研究为垃圾渗滤液的治理提供了新的解决方案。     

Effect of perchloroethylene (PCE) and hydraulic shock loads on a membrane‐aerated biofilm reactor (MABR) biodegrading PCE

BACKGROUND: A membrane‐aerated biofilm reactor (MABR) has previously been used to provide both anaerobic and aerobic conditions for mineralisation of perchloroethylene (PCE). However, very little is known about the stability of this reactor under hydraulic and PCE shock loads. An MABR was therefore subjected to sudden hydraulic and PCE shock loads in order to investigate its stability under such conditions. RESULTS: After each shock, the reactor responded with an increase of chemical oxygen demand (COD) and volatile fatty acids (VFA)s, a breakthrough of PCE and its biodegradation intermediates in the effluent, and a decrease in methane production. Although some PCE biodegradation intermediates were found in the effluent during each shock loading, the MABR performance recovered without the accumulation of any particular PCE biodegradation intermediates during PCE shock loads. During the hydraulic shock loads, the MABR was unstable at hydraulic retention times (HRTs) of 6 h with PCE and its biodegradation intermediates detected in the effluent. However, these intermediates were degraded when the HRT was reset to 48 h. CONCLUSIONS: This study suggests that MABRs can withstand fluctuations in influent strength and flows which occur in wastewater treatment works. Copyright © 2009 Society of Chemical Industry     

Occurrence and biodegradation of nonylphenol in the environment

Nonylphenol (NP) is an ultimate degradation product of nonylphenol polyethoxylates (NPE) that is primarily used in cleaning and industrial processes. Its widespread use has led to the wide existence of NP in various environmental matrices, such as water, sediment, air and soil. NP can be decreased by biodegradation through the action of microorganisms under aerobic or anaerobic conditions. Half-lives of biodegradation ranged from a few days to almost one hundred days. The degradation rate for NP was influenced by temperature, pH and additions of yeast extracts, surfactants, aluminum sulfate, acetate, pyruvate, lactate, manganese dioxide, ferric chloride, sodium chloride, hydrogen peroxide, heavy metals, and phthalic acid esters. Although NP is present at low concentrations in the environment, as an endocrine disruptor the risks of long-term exposure to low concentrations remain largely unknown. This paper reviews the occurrence of NP in the environment and its aerobic and anaerobic biodegradation in natural environments and sewage treatment plants, which is essential for assessing the potential risk associated with low level exposure to NP and other endocrine disruptors.     

Kinetic analysis of thermal degradation of NR/EPDM blends: Effect of the reactive compatibilization

The effect of mercapto‐modified EPDM (EPDMSH) and thioacetate‐modified EPDM (EPDMTA) on the thermal degradation of NR/EPDM (70 : 30 wt %) blends has been investigated under anaerobic and aerobic conditions. The anaerobic condition consisted of compression‐molding the samples at different times, higher than the optimum curing time established by the oscillatory disk rheometer. The aerobic conditions consisted of ageing the samples in an air circulating oven. EPDMTA in the blend resulted in a reasonable retention of mechanical properties of sample ageing in an air‐circulation oven, and a slight increase of crosslink density after ageing under anaerobic conditions. EPDMSH resulted in an accentuated ageing degradation under anaerobic and aerobic conditions. The kinetic parameters of thermal degradation were evaluated from non isothermal TGA experiments taken at different heating rates. The presence of functionalized copolymers in a proportion as low as 2.5 wt % in the blends resulted in a substantial increase of the activation energy, indicating an increase of the resistance against thermal degradation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2669–2675, 2007