Improving sustainability through effective reuse of product returns: minimizing waste in a batch blending process environment

A case study of a successful reuse program in a batch blending production environment is presented. This program involves not only addressing the company's own potential waste, but also working with distributors and customers to take back and reuse product, thus eliminating the customers' burden of disposal. Implications of the program for downstream supply chain partners are identified and a structured approach for implementation is presented. Modification for use in similar production environments is possible, enhancing sustainability, while providing environmental as well as economic benefits.     

悬浮型和流化床型纳米TiO2光催化反应器研究进展

围绕避免催化剂沉积、提高光透过率和催化剂分离3个方面的问题,综述了国内外在悬浮型和流化床型光催化反应器的工艺设计及改良方面所取得的进展,对当前应发展的悬浮型和流化床型反应体系提出了建议。     

Temperature and feed strategy effects on sulfate and organic matter removal in an AnSBB

The objective of this work was to analyze the interaction effects between temperature, feed strategy and COD/[SO(4)(2-)] levels, maintaining the same ratio, on sulfate and organic matter removal efficiency from a synthetic wastewater. This work is thus a continuation of Archilha et al. (2010) who studied the effect of feed strategy at 30 °C using different COD/[SO(4)(2-)] ratios and levels. A 3.7-L anaerobic sequencing batch reactor with recirculation of the liquid phase and which contained immobilized biomass on polyurethane foam (AnSBBR) was used to treat 2.0 L synthetic wastewater in 8 h cycles. The temperatures of 15, 22.5 and 30 °C with two feed strategies were assessed: (a) batch and (b) batch followed by fed-batch. In strategy (a) the reactor was fed in 10 min with 2 L wastewater containing sulfate and carbon sources. In strategy (b) 1.2 L wastewater (containing only the sulfate source) was fed during the first 10 min of the cycle and the remaining 0.8 L (containing only the carbon source) in 240 min. Based on COD/[SO(4)(2-)] = 1 and on the organic matter (0.5 and 1.5 gCOD/L) and sulfate (0.5 and 1.5 gSO(4)(2-)/L) concentrations, the sulfate and organic matter loading rates applied were 1.5 and 4.5 g/L.d, i.e., same COD/[SO(4)(2-)] ratio (=1) but different levels (1.5/1.5 and 4.5/4.5 gCOD/gSO(4)(2-)). When reactor feed was 1.5 gCOD/L.d and 1.5 gSO(4)(2-)/L.d, gradual feeding (strategy b) showed to favor sulfate and organic matter removal in the investigated temperature range, indicating improved utilization of the electron donor for sulfate reduction. Sulfate removal efficiencies were 87.9; 86.3 and 84.4%, and organic matter removal efficiencies 95.2; 86.5 and 80.8% at operation temperatures of 30; 22.5 and 15 °C, respectively. On the other hand, when feeding was 4.5 gCOD/L.d and 4.5 gSO(4)(2-)/L.d, gradual feeding did not favor sulfate removal, indicating that gradual feeding of the electron donor did not improve sulfate reduction.     

Comparative analysis of impact of human occupancy on indoor microbiomes

• Exposure to indoor microbiomes is a public health concern in educational facilities. • Indoor microbiomes were characterized in two multifunctional university buildings. • Human occupancy had significant impact on the composition of indoor microbiomes. • The skin microbiota of occupants represented important sources of indoor microbiomes. Educational facilities serve as community hubs and consequently hotspots for exposure to pathogenic microorganisms. Therefore, it is of critical importance to understand processes shaping the indoor microbiomes in educational facilities to protect public health by reducing potential exposure risks of students and the broader community. In this study, the indoor surface bacterial microbiomes were characterized in two multifunctional university buildings with contrasting levels of human occupancy, of which one was recently constructed with minimal human occupancy while the other had been in full operation for six years. Higher levels of human occupancy in the older building were shown to result in greater microbial abundance in the indoor environment and greater proportion of the indoor surface bacterial microbiomes contributed from human-associated microbiota, particularly the skin microbiota. It was further revealed that human-associated microbiota had greater influence on the indoor surface bacterial microbiomes in areas of high occupancy than areas of low occupancy. Consistent with minimal impact from human occupancy in a new construction, the indoor microbiomes in the new building exhibited significantly lower influence from human-associated microbiota than in the older building, with microbial taxa originating from soil and plants representing the dominant constituents of the indoor surface bacterial microbiomes. In contrast, microbial taxa in the older building with extensive human occupancy were represented by constituents of the human microbiota, likely from occupants. These findings provide insights into processes shaping the indoor microbiomes which will aid the development of effective strategies to control microbial exposure risks of occupants in educational facilities.     

异养硝化细菌处理氨氮废水及影响因素研究

从生物陶粒反应器中筛选出6株异养硝化细菌,将异养硝化细菌扩大培养后,建立SBR反应器并进行了氨氮去除的试验研究。在SBR反应器进入稳定运行阶段时,可以观察到系统对于氨氮的去除率稳定在82．96％左右,表现出较好的氨氮去除效果;出水亚硝酸盐含量一直维持在较低的水平,其最大值不超过3．84mg·L-1;COD的平均去除率为54．72％,基本实现了同一反应器中的有机物和氨氮的共同去除。异养硝化SBR反应器温度为29℃时,反应器对氨氮和总氮的去除能力最大为82．28％和47．27％;在pH值为8．0时,氨氮去除率最高达到80．15％。C／N〈4．5时,随着C／N比的增加,氨氮和总氮的去除率快速增加;在C/N为6时,氨氮去除率最高达到87．62％。     

关于厌氧流化床稳态机理模型和参数估计模型的推理性研究

本研究采用化繁为简的模型图式、质量平衡原理和实验中的经验数据进行了厌氧流化床消化有机废液过程稳态机理模型的推理,继而对机理模型作了线性化处理,得到厌氧流化床运行的稳态参数估计模型。这些模型可用于厌氧流化床运行的在线控制,具有理论和实用价值。     

铁屑过滤-SBR工艺处理印染废水的研究

采用铁屑过滤－ＳＢＲ工艺对印染废水进行了处理研究,当进水ＣＯＤ为１０００－１６００ｍｇ／Ｌ,色度为２００－８００倍,ＢＯＤ５在２００－４００ｍｇ／Ｌ时,ＣＯＤ去除率可达８５％,ＢＯＤ５去除率和脱色率均在９０％以上,出水达到排放标准,该工艺具有投资少,运行费用低,处理效果稳定等特点,尤其适合中小型印染厂的废水治理。     

生物紊动床的水力特性及硝化效能研究

试验研究了生物紊动床的水力特性及硝化效能。试验结果表明 ,生物紊动床从整体上表现为完全混合型流态特征。在温度T =2 5℃ ,HRT =5h ,容积负荷Nv在 0 .32 4～ 1 .994kgN/m3·d的范围内 ,氨氮去除率均能保持在 95 %以上。     

SBR法处理高浓度有机废水试验研究

采用序批式活性污泥法（SBR），对处理高浓度化工废水进行了实验研究，结果表明，温度是影响SBR法处理效果的一处重要因素，其次是pH值、曝气量和周期，并在一定条件下，可得到75％的CODcr去除率。     

HCR工艺在化工废水处理中的应用

HCR反应器具有所需空间少、占地省、设计集成合理、COD降解率高、空气氧利用率高且操作便利安全等优点。在具有高含盐量、高COD值,可生化性差的化工废水处理工程实例中,取得了良好的实效,验证了HCR工艺系统的实用价值及稳定可靠的性能,体现了HCR工艺系统在化工废水处理领域的优势。