Characterization of the genes involved in nitrogen cycling in wastewater treatment plants using DNA microarray and most probable number-PCR

To improve nitrogen removal performance of wastewater treatment plants (WWTPs), it is essential to understand the behavior of nitrogen cycling communities, which comprise various microorganisms. This study characterized the quantity and diversity of nitrogen cycling genes in various processes of municipal WWTPs by employing two molecular-based methods:most probable number-polymerase chain reaction (MPN-PCR) and DNA microarray. MPN-PCR analysis revealed that gene quantities were not statistically different among processes, suggesting that conventional activated sludge processes (CAS) are similar to nitrogen removal processes in their ability to retain an adequate population of nitrogen cycling microorganisms. Furthermore, most processes in the WWTPs that were researched shared a pattern:the nirS and the bacterial amoA genes were more abundant than the nirK and archaeal amoA genes, respectively. DNA microarray analysis revealed that several kinds of nitrification and denitrification genes were detected in both CAS and anaerobic-oxic processes (AO), whereas limited genes were detected in nitrogen removal processes. Results of this study suggest that CAS maintains a diverse community of nitrogen cycling microorganisms; moreover, the microbial communities in nitrogen removal processes may be specific.

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Environmental deterioration of farmlands caused by the irrational use of agricultural technologies

Without considering the ecosystem-dependence of agricultural production, irrational use of agricultural technologies could bring only short-term economic benefits but leave long-term environmental deterioration. If some agricultural lands have to be abandoned because of these technologies such as chemical films or groundwater depletion, it will aggravate the burden of remaining lands for maintaining or enhancing production. Thus, agricultural production should be a part of public services, requiring the consideration of interests of different stakeholders and sustainability.     

餐厨垃圾的黑水虻处理中含钙矿物及微生物对油脂转化效率的影响

黑水虻处理是近年来发展起来的一种餐厨垃圾的有效资源化方法,但由于黑水虻的生理特性,油脂类物质经常不能被彻底降解和去除,残渣仍有酸败气味,需堆肥化二次处理.为了提高油脂类成分的降解效率,提升黑水虻富集油脂的资源化能力,本研究拟以含钙矿物和微生物为主要辅助手段,通过向餐厨垃圾中添加湿重比例为0~10%的CaCO₃、0~10%的Ca(OH)₂、5%CaCO₃和菌液的混合物及6种不同菌液,研究含钙矿物和微生物对于油脂减量化和虫油转化效率的影响.结果发现,向餐厨垃圾中添加含钙矿物,能够显著调节和缓冲黑水虻处理过程中的环境pH值,但对增加油脂的去除效率和黑水虻油脂的转化能力没有显著作用.而且添加7%~10% 的CaCO₃对于餐厨垃圾的减量化率和黑水虻的虫产率有负作用,添加5%~10%的Ca(OH)₂会导致显著的幼虫死亡率.同时添加CaCO₃和菌液对于油脂的去除不利.仅添加微生物菌液是提高垃圾油脂减量化率和黑水虻油脂富集率的最有效方法.枯草芽孢杆菌NJZ菌株、地衣芽孢杆菌NY菌株、植物乳酸杆菌RS72菌株和粪肠球菌L102菌株,是提高黑水虻油脂转化效率的有效菌株.添加微生物后,黑水虻的虫油产率由对照组的10.4%提升至12.8%~14.4%,虫油富集率由对照组的93.9%提升至116%~130%.虫油富集率超过100%,说明餐厨垃圾中碳水化合物、蛋白质等非油脂成分的一部分转化为黑水虻的体脂,而微生物的辅助降解可能是强化这一过程的主要因素.但即使在接种微生物以后,虫沙中仍然有29%~44%的油脂在处理结束时剩余,说明餐厨垃圾中的油脂较难被彻底降解和利用.未来研究中,可以继续筛选高效降解油脂的微生物,与黑水虻共同处理餐厨垃圾,实现油脂成分的资源化全利用.     

厨余发酵液作为中试A/O-MBR外增碳源的脱氮特性

利用厨余发酵液作为A/O-MBR的外增碳源,考察在不同发酵液投加量和水力停留时间(HRT)条件下的脱氮性能以及膜污染特点.结果表明,发酵液的反硝化速率和COD利用率与乙酸钠接近,比葡萄糖高.通过A/O-MBR的运行发现,厨余发酵液作为碳源能够增强微生物活性,强化反硝化过程,从而提高脱氮效率.TN的去除效率随着发酵液投加量的增加而增大.发酵液投加前后,反应器内的EPS并没有积累,膜污染速率变化较小.化学清洗可以有效地去除膜污染物质,恢复膜通量.同时,延长HRT有助于提高脱氮效率和缓解膜污染.     

A fresh perspective on food safety in Canada: risk communication,public involvement,and the impact of the 2008 listeriosis outbreak

While the listeriosis outbreak of 2008 brought attention to food safety decision making in Canada, little of that attention was placed on public involvement and risk communication. With a primary focus on Health Canada (HC) and the Canadian Food Inspection Agency (CFIA), this article describes the state of microbial-related public involvement and risk communication undertakings and suggests ways in which improvements can be made. The findings show that public involvement and risk communication activities have been strengthened since the outbreak, but they have become neither dialogical nor highly participatory. HC engages with experts to a far greater extent than with the lay public and it has fallen short in fulfilling its stated commitment to openness and transparency. Furthermore, both HC's and the CFIA's approach to risk communication has been overly general, has failed to provide opportunities for dialogue with vulnerable and more general groups with whom it is communicating and is not rooted in foodborne surveillance data. Public involvement in food safety governance would be improved if HC provided the lay public with a seat on advisory committees and improved its public involvement reporting methods. HC and the CFIA could also make risk communication improvements by creating opportunities for dialogue between officials and the general public, and by exploring alternative risk communication vehicles, such as food labels.     

Changes in polybrominated diphenyl ether (PBDE) levels in cooked food

Food surveys for levels of toxic chemicals frequently report the levels on an uncooked basis. It is known that cooking may in some conditions decrease the amount of dioxins and related chemicals in food. Surveys of polybrominated diphenyl ether (PBDE) levels in food to date show data from uncooked food only. In this article, it was shown that broiling, with fat dripped from the foods reported here, ground beef, ground lamb, catfish, trout, and salmon, reduces the amount of PBDEs in these foods. This suggests that calculations of food intake need to take into consideration levels in the cooked food rather than in the uncooked food.     

Empirical analysis on the influence of the Shaanxi fruit industry on regional food security

As part of its development policy to relieve rural poverty in west China, the Chinese government has introduced measures such as agricultural tax exemptions, agricultural subsidies, and scientific, technological and restructuring improvements to agriculture. Following these actions, farmers’ incomes have increased greatly and the economy in poor areas of west China has seen rapid improvements. However, agricultural restructuring, infrastructure construction and ecological restoration projects have reduced the area of land under arable farming, restricting opportunities for increasing total grain yield. Regional food security is therefore threatened and an imbalance between economic development and food security is created. Shaanxi is a representative province in west China where agricultural restructuring has resulted in large areas of arable land being converted into orchards that produce higher economic returns. This study randomly surveyed 1430 farm households in three counties in the apple-producing region of Shaanxi Province (Luochuan, Changwu and Baishui). The standard of living and household income of farmers in the fruit production areas were higher than in grain-producing areas, thus discouraging grain production. Land under agriculture in the counties studied comprised 59% orchards and 39% arable, with 2% under other uses. Per capita, 204.3 kg of grain was produced, 51% of that required for self-sufficiency. Other staple foods produced amounted to only 13.9% of that needed for self-sufficiency. As a result, nearly half of the grain needed by the community was purchased from outside, resulting in very poor regional food security. Clearly, fruit production in this region seriously affects regional food security. Coordination of relationships between rural economic development and regional food security is key for sustainable development of the regional agriculture and economy of west China.     

Prioritization of applicable drivers for green supply chain management implementation toward sustainability in Thailand

ABSTRACT

It is essential that the green supply chain management (GSCM) implementation is effectively supported by several strategic drivers for successful implementation and sustainability, especially for the ‘green’ start-ups with a sustainability-driven organizational strategy. This study aims to determine and prioritize the applicable drivers for GSCM implementation of sustainable development strategies in the electronics industry in Thailand. The applicable drivers and their priorities are obtained by applying the fuzzy group decision-making approaches including fuzzy Delphi and fuzzy Analytic Hierarchy Process, based on Thai experts’ perspectives. In this study, three prominent organizational theories, resource-based view, relational view, and institutional theory, are needed to explain the drivers of sustainability and to develop a hierarchical model for prioritization of the drivers. Finally, based on the findings of this study, several recommendations are made that may help to improve the sustainable development in Thailand through more effective implementation of GSCM.     

森林净生态系统生产力及其生物影响因子研究进展

在全球大气二氧化碳浓度上升的背景下,陆地生态系统碳循环及碳汇功能研究得到了广泛的关注,日益成为今后的政治和外交的重大议题之一.净生态系统生产力(net ecosystem production, NEP)是生态系统光合固定的碳与生态系统呼吸损失的碳之间的差值;或者为生态系统净的碳积累速率.NEP 的研究整合生态系统地上和地下部分,把生态系统碳循环的影响因子有机地联系了起来.当NEP为正值时,说明生态系统为碳汇,NEP为负值则表明生态系统为碳源.随着植物和土壤相互联系及其对生态系统过程研究的深入,NEP已经成为生态系统碳循环研究的核心概念之一.以森林NEP为出发点,综述了国内外的最近的 NEP 研究进展,分析了 NEP 研究的科学意义;探讨了植物群落组成/生物多样性、土壤微生物群落、大型/土壤动物和人为的管理或干扰等生物因子对NEP的影响.根据综述研究提出未来研究应在:(1)土壤生物过程、土壤食物网及其与地上部分植物/动物相互作用对NEP的影响;(2)自然林生物多样性的竞争/共存机制与生态系统碳吸存稳定性;(3)人工林固碳潜力和不同植物功能群(灌草层)对生态系统碳动态影响等方面加强,以期为全面认识生物因子对森林生态系统系统固碳现状、机制和潜力提供理论基础.     

Metal removal with two biochars made from municipal organic waste: adsorptive characterization and surface complexation modeling

The adsorptive characteristics of biochar produced from garden green waste (S-char) and a mixture of food waste and garden green waste (FS-char) were investigated. Adsorption of Cu²⁺, Zn²⁺, and Mn²⁺ onto the two biochars reached equilibrium within 48 hours. The metal adsorption was effectively described by the pseudo-second-order kinetic and Freundlich isotherm models which suggest heterogeneous chemisorption. The initial solution pH influenced adsorption of Zn²⁺ and Mn²⁺ but not of Cu²⁺. Simulation via a surface complexation model showed that the fraction of XOCu⁺ adsorbed onto biochar was increased with increasing pH until it reached the adsorption maximum at pH 8.5, while the endpoint for the maximum of XOMn⁺ was higher than pH 12.