4种粪便堆肥过程中抗生素的降解特性

饲料中抗生素的广泛使用导致了粪便中抗生素的大量残留,堆肥工艺可以降解残留的抗生素.本研究以蛆粪、鸡粪、猪粪和牛粪为对象,利用中试好氧堆肥装置,研究不同类型粪便的抗生素残留情况及其堆肥降解特性.结果表明,磺胺类、氟喹诺酮类、四环素类和大环内酯类是主要存在的抗生素类型,不同类型粪便其优势抗生素均不同.对各粪便堆肥中抗生素降解规律研究发现:氟喹诺酮类抗生素和土霉素在堆肥第7 d检出水平为0,降解速度最快;强力霉素在4种粪便堆肥中的降解幅度在85%以上;磺胺类抗生素在鸡粪、猪粪和牛粪堆肥中的降解幅度在80%以上,但是在蛆粪堆肥中的降解效果较差;大环内酯类抗生素仅存在蛆粪中,经堆肥其降解幅度为70. 79%.相关性结果显示,含水率和容重是影响4种粪便堆肥抗生素降解率最主要的环境因子.     

Public participation mechanisms and sustainable policy-making: a case study analysis of Mexico City's Plan Verde

Mexico City has gained an international reputation for its ground-breaking approach to sustainability as a result of policies implemented during the Marcelo Ebrard administration (2006–2012). In this paper, we examine the development and implementation of the Plan Verde de la Ciudad de México (Green Plan), the 15-year policy aimed to transform Mexico City into the most progressive and sustainable city in Latin America. Key to the plan's success, it was claimed, would be the active participation of stakeholders from all levels of society. Drawing on documentary material and interviews, we argue that whilst the plan did have a significant impact on the environmental sustainability of the megacity, it failed to include effective citizen participation mechanisms. As predicted by several members of the Green Plan Monitoring and Assessment Board, this lack of representation, alongside other failures, appears to have facilitated the premature demise of the plan under the new administration.     

玉米秸秆作为生态厕所基质处理人粪便的实验研究

利用日本科学技术振兴机构赠送的S-15型生态厕所,以玉米秸秆作为反应基质来处理人粪便,旨在研究玉米秸秆能否代替木屑作为生态厕所的反应基质.实验过程中,对粪便和玉米秸秆混合物的减量化情况、物理性状的变化以及温度、湿度、pH值、有机质、N、P、K等营养元素和碳氮比的变化情况进行了监测.结果表明:玉米秸秆能够代替木屑作为生态厕所的反应基质,且能够有效的降解人粪便,整个反应过程中粪便和玉米秸秆混合物的干重减少率为37.3%.最终残余物的pH值和碳氮比分别为8.02和13.7,且含有大量的N、P、K等营养物质,可以作为有机肥.     

猪粪与玉米秸秆混合中温发酵产气效果

以猪粪及碱液预处理后的玉米秸秆为原料,在恒温35℃和料液总固体质量分数为5%的条件下,以实验室内培养的不产气厌氧活性污泥为接种物,研究猪粪与玉米秸秆不同配比(干物质比分别为1:3、1:2、1:1、2:1、3:1和0:1(单一猪粪))混合发酵对产气效果的影响.研究结果表明,在35℃条件下,猪粪与玉米秸秆以2:1配比的累积产气量最大,为15 157 mL;其次是1:1样品,累积产气量为15 088 mL.但甲烷产量最高为1:1样品,56 d共产甲烷9 137 mL,甲烷气占总产气量的60.6%.通过对发酵过程中pH及COD的测定,证明经碱液预处理后的玉米秸秆能与猪粪混合稳定发酵,发酵前后厌氧消化液中COD的降解率可达50%以上.进一步研究分析得出,将玉米秸秆和猪粪按一定比例混合发酵不仅可以缩短发酵周期、提高产气速率,而且可以大幅提升原料的产气潜力.     

Green fairs as venues for civic engagement

We present the first systematic research on green fairs in the USA. We provide a summary analysis of the frequency, trends, goals, structure, and operations of green fairs being held in the USA. We also present an initial assessment of their potential contributions to civic engagement through a study of the intentions and behaviour of fair organisers and fair goers. This assessment is premised on previous research in civic engagement and similar local events with environmental themes, such as farmers' markets. Green fairs are recent, yet now common, events in the USA. Although brief and informal experiences for attendees, green fairs are rich with opportunities to engage people in their community on sustainability and other environmental issues. They are important venues for civic engagement that are distinct from both farmers' markets and from more formal settings for engagement.     

生物质降解人体排泄物试验研究

采用S-15型生物反应器为试验装置,以生物质秸秆作为反应基质,研究了反应基质营养元素含量变化和人体粪便的减量化过程。试验过程中检测了总氮、总磷、总钾、有机质和pH值等指标,着重分析了总有机质和氮含量变化。试验结果表明生物质秸秆处理人体排泄物具有很好的减量化效果,粪便处理效率97%。终产物中有机质总量70%,pH值9.1,TN、TP、TK含量分别为2.5%、1.22%和3.07%,养分含量明显增加,是一种很好的有机肥。利用生物质降解人体排泄物充分实现了废物的资源化,具有良好的推广前景。     

梨形筒式好氧堆肥反应器的开发与应用

针对现有堆肥反应器移动困难、难以使物料充分混合及堆肥效率不稳定等问题,开发了梨形筒式好氧堆肥反应器。从物料和热量平衡、通风量及搅拌方式优化等方面对反应器进行了研究。反应器主要包括梨形筒体、无轴螺旋导叶、通风系统、动力系统和控制系统等,具有易于移动、便于进/出料等优点。在通风量为2.0 L/min,初始物料投加量5.0kg（干重比∶粪便/锯末=1∶4）,含水率约60%时,利用反应器对人粪便进行序批式堆肥实验,结果表明,反应器搅拌5 min后混合均匀率可达90%以上,符合混合均匀度的要求;堆体温度从第2天开始升温至50℃以上并保持30 d;TOC和COD均呈持续下降趋势,降解率分别为72.61%和72.81%;种子发芽指数为92.18%,可完全达到腐熟标准。     

好氧堆肥反应器对人粪便堆肥中温降解的中试研究

控制温度为（35±2）℃,以新鲜锯末为空白载体,在控制含水率为55%~60%和强制通风的好氧条件下,进行为期15 d的实验,进行了人粪便好氧堆肥的中试研究,重点分析了在堆肥过程中有机物的降解、氮素的迁移转化规律及生物量的变化。结果表明,粪便中有机物含量在前2天稍微上升,然后迅速下降,最终去除率为71.82%;随着NH₃-N释放量的增加,堆料中N_tot含量从第4天开始减少,最终损失 22.61%,其中N_org损失占74.35%,NH₃-N占23.52%;所损失的氮素有91.66%以氨氮的形式释放。粪便中的有机物和氮的含量能在8~10 d后达到稳定,且堆体无臭味;粪便中溶解性有机物为微生物的生长提供营养物质,因此生物量变化的过程与有机物降解的有着紧密的联系;病原菌在堆肥过程中得到有效去除,表明该反应器堆肥的无害化。