Enhanced treatment efficiency of an anaerobic sequencing batch reactor (ASBR) for cassava stillage with high solids content

Cassava stillage is a high strength organic wastewater with high suspended solids (SS) content. The efficiency of cassava stillage treatment using an anaerobic sequencing batch reactor (ASBR) was significantly enhanced by discharging settled sludge to maintain a lower sludge concentration (about 30 g/L) in the reactor. Three hydraulic retention times (HRTs), namely 10 d, 7.5 d, 5 d, were evaluated at this condition. The study demonstrated that at an HRT of 5 d and an organic loading rate (OLR) of 11.3 kg COD/(m³ d), the total chemical oxygen demand (TCOD) and soluble COD (SCOD) removal efficiency can still be maintained at above 80%. The settleability of digested cassava stillage was improved significantly, and thus only a small amount of settled sludge needed to be discharged to maintain the sludge concentration in the reactor. Furthermore, the performance of ASBR operated at low and high sludge concentration (about 79.5 g/L without sludge discharged) was evaluated at an HRT of 5 d. The TCOD removal efficiency and SS in the effluent were 61% and 21.9 g/L respectively at high sludge concentration, while the values were 85.1% and 2.4 g/L at low sludge concentration. Therefore, low sludge concentration is recommended for ASBR treating cassava stillage at an HRT 5 d due to lower TCOD and SS in the effluent, which could facilitate post-treatment.     

铁碳微电解预处理化工有机废水研究

某化工厂废水主要成份为乙醇等小分子有机物,经蒸馏处理后出水CODCr浓度在2000～4000mg/L之间,BOD5/CODCr只有0.15,因此采用铁碳微电解方法进行预处理。实验结果表明,最合适反应条件是进水pH值为3.0、铁碳比l∶1、水力停留时间为1.5h,在此条件下CODCr去除率可达95%以上。而且,出水BOD5/CODCr值在0.45以上,提高了可生化性。     

一体化AmOn工艺处理城市污水试验

本文主要研究了不同工艺运行参数对一体化AmOn工艺处理城市污水效果的影响,试验表明,AmOn工艺适宜的水力停留时间为8．5h,这使得工艺整体的处理效率处于较高水平;当水温在20℃以上时,AmOn、工艺适宜的污泥龄为10d;好氧区D0浓度处于2．5～4．5mg／L．之间时,AmOn工艺的整体脱氛除磷效果较好。     

深度聚类索引下的海量地震数据快速三维可视化

地震数据的三维可视化能够直观反映地质的相关结构信息,为地质勘探等研究提供数据支持。针对传统体绘制算法在集中载入海量数据时存在显示延迟、画面跳跃、卡顿等问题,提出一种快速三维可视化算法。使用变分自编码器和深度聚类学习数据的空间特征表示,通过迭代优化目标函数提高聚类性能,以解决因空间数据分布不均造成的节点重叠问题。建立高效的索引结构,提高数据实时读取的效率,通过时序卷积网络预测下一个视点位置,提前将潜在数据载入内存,避免因海量数据集中加载导致画面卡顿、跳跃。使用基于双层视锥体的视点动态划分调度模型,剔除不必要的绘制节点及减轻系统负荷,从而提高数据渲染速度和流畅度。实验结果表明,该算法在索引结构上查询数据块的时间相比希尔伯特R树算法减少了64.14%～66.37%,预测视点的正确率相比拉格朗日插值算法提高了12.08%～22.70%,实时帧率在较大规模的子集上也能够相对稳定平滑,在保证图像质量的前提下整体系统的渲染性能达到预期效果。     

HRT对UASB-SMBR(PTFE)组合工艺处理某油田含油废水性能的影响

 利用升流式厌氧污泥床(UASB)与膜生物反应器(MBR)组合工艺处理含油废水,在不同的水力停留时间(HRT)下考察了系统对NH₃-N、石油类污染物和挥发酚去除以及COD和浊度降低的效果,也考察了膜污染和清洗情况。结果表明,该组合工艺对各种污染物质都有很好的去除效果,出水水质能够满足国家污水综合排放一级标准, NH₃-N、石油类污染物、挥发酚的平均去除率以及CO和浊度的降低率分别达到98.58%、98.33%、99.83%、95.00%和99.84%;污染物的去除效率随着水力停留时间的缩而降低。在实验过程中还发现,在不同水力停留时间下会产生不同程度的膜污染,且水力停留时间的长短与膜染的速率呈反相关关系;采用四步法清洗后,聚四氟乙烯(PTFE)膜的透水性基本完全恢复。UASB-SMBR(PTFE)组合工艺能够稳定运用于含油废水的处理。     

用浸没式平板膜生物反应器处理草浆中段废水

用自制浸没式平板膜生物反应器(MBR)对麦草浆中段废水进行处理,CODCr、色度和SS的去除率分别为90.0%、92.3%和96.0%,出水达到制浆造纸工业水污染物排放标准(GB3544—2008)的排放要求。处理过程中通过优化运行参数有效减缓了膜污染的发生。     

有机负荷对ABR系统运行特征及效能的影响

为提高厌氧折流板反应器（ABR）的处理效能,采用有效容积为28.75L的4格室ABR,通过进水COD质量浓度和水力停留时间（HRT）的调控,探讨有机负荷率（OLR）的改变对系统运行特征和效能的影响.结果表明,在OLR为4.0～5.4kg·m-3·d-1范围内,通过进水COD质量浓度和HRT的调控,可使参与厌氧消化过程的...     

泥水混合水解酸化预处理下同步硝化反硝化除磷颗粒污泥运行

为实现生活污水下同步硝化内源反硝化除磷(SNEDPR)系统的稳定运行,选用SBR接种人工配水培养的SNEDPR颗粒污泥,以实际生活污水和污泥经混合水解酸化预处理为进水基质,通过优化预处理单元水力停留时间(HRT)联合SBR排泥方式实现该系统稳定运行。结果表明,预处理单元HRT从12 h降至4 h时,水解酸化液提供的乙酸、丙酸质量浓度和挥发性脂肪酸(VFA)占比提高,好氧颗粒污泥(AGS)内厌氧聚羟基烷酸(PHA)储存量增加,同步硝化反硝化(SND)效率提升至58.1%,出水TN降至7.8 mg/L左右。同时,底部排泥的SBR内小颗粒占比上升、LB-EPS增加,系统沉降性能变差;顶部排泥下成熟老化的大颗粒占比上升,颗粒含水率和强度下降;而选择性排泥的SBR内颗粒粒径集中在0.5～0.9 mm,颗粒结构密实、强度高,颗粒内细菌分层分布增强SND效果,批次实验表明,NOB和GAOs活性降低,系统内以NO^-₂为电子受体的DPAOs占比提升至40.5%,同步硝化内源反硝化除磷效率得到提升。预处理单元较短的HRT联合选择性排泥处理生活污水颗粒性能稳定,系...     

Environmental assessment of electricity generation from an Italian anaerobic digestion plant

A standard ISO Life Cycle Assessment study was carried out to evaluate the environmental sustainability of electricity production from an anaerobic digestion (AD) plant using a mixture of dedicated energy crops, agricultural residues and livestock effluents as input materials. The functional unit was 1 MJ of electricity. System boundaries were from cradle to grave and covered all the phases from energy crops cultivation to the production of biogas and its use in a Combined Heat and Power plant to produce electricity. Liquid and solid digestate storage and spreading on agricultural land were included. Primary data were collected from the AD plant for all the above phases. Since heat produced is used only internally, no allocation was applied in the study. As regards digestate management, CH₄ emissions were calculated from literature, whereas four literature methods were applied for calculation of nitrogen emissions with the goal to perform a sensitivity analysis on LCA results. ILCD Handbook impact assessment methodologies were used. Results show that the main hotspots are energy crops cultivation and the management of digestate, mainly because of both nitrogen and methane emissions, affecting Global Warming, Acidification, Marine and Freshwater Eutrophication. Finally, a detailed Monte Carlo analysis, was carried out to evaluate the results uncertainty. The study represents the state of the art about the environmental performance of the AD plant with the use of sensitivity and uncertainty analysis, which both improve the reliability of results, and allows drawing general conclusions on how to mitigate the environmental impacts of AD process.     

初次沉淀池短时沉降效应的模拟试验研究

针对在活性污泥法工艺中究竟应该取消还是保留初沉池这一争论．通过静态和动态沉淀模拟试验，研究初沉池的水力停留时间与初沉池沉降效应的关系，以确定比较合适的初沉池水力停留时间．研究表明，初沉池沉淀时间控制在0.5～1.0h之内应该是适当的，一方面可维持初沉池的本来功能，同时也缓解脱氮除磷中存在的碳源矛盾；另一方面可降低工程基建投资．