Risk discourses and governance of high-level radioactive waste storage in Taiwan

Policy scholars have indicated that the quality of the solution to a perceived social problem depends on the adequacy of its framing. This paper examines how policy stakeholders and local residents frame the issue of the radioactive waste storage facility in Taiwan, the limits of institutional mechanisms in decision-making processes, and the implications of the deliberative forums undertaken by the national Stop Nukes Now organisation. The controversy illustrates the problems of a knowledge gap and the top-down procedures as well as the challenges that Taiwan faces in becoming a nuclear-free country. This case demonstrates civic society organisations’ efforts to challenge the ‘social–technical divide’ and technical experts’ prior definition of the ‘problems’ and selection of a ‘solution’. Deliberative forums enable the participation of affected communities to shape public discourses, which helps to strengthen public communication, improves citizen consciousness of nuclear waste issues, and attempts to link wider communities and public interests.     

Property rights integrity,tenure security and forestland rental market participation: Evidence from Jiangxi Province,China

The decentralization of property rights is the focus of the forest tenure reforms in several developing countries. In China, it was achieved by the launch of a new round of collective forest tenure reform beginning in 2003, which provided farmers with more integrated and secure forestland rights. Drawing on household data collected in Jiangxi province in 2011 and 2013, this paper examines the impacts of households’ recognition of property rights and improved tenure security on forestland rental activities. Our empirical results show that households with higher perceptions of more complete use rights and mortgage rights have a lower probability and intensity of renting‐in land, while households with lower expectations of future forestland redistribution or expropriation are more likely to rent in forestland and more of it. These results imply that the development of a forestland rental market leading to better forest management requires an integrated forestland management approach consisting of decentralization of property rights and village governance. In particular, the central government may further clarify the rights and obligations affiliated to forestland ownership, contractual rights, and management rights; while the village collective may shift from direct intervention in the integrity and security of forestland rights to the supervision and protection of decentralized forestland rights to increase efficiency from the decentralization of property rights.     

Release characteristics of mercury in chemical looping combustion of bituminous coal

This study evaluated the release characteristics of mercury from bituminous coal in chemical looping combustion (CLC) using Australian iron ore as the oxygen carrier in a fixed bed reactor. The effects of several parameters, such as temperature in the fuel reactor (FR) and air reactor (AR), gasification medium in the FR, and reaction atmosphere in the AR, on mercury release characteristics, were investigated. The mercury speciation and release amount in the FR and AR under different conditions were further explored. The results indicate that most of the mercury in coal was released in the FR, while the rest of it was released in the AR. Hg⁰ was found to be the major species in the released mercury. The results also indicate that a higher temperature in the FR led to an increase in the total mercury release amount and a decrease in Hg⁰ proportion. However, a higher temperature in the AR resulted in a decrease in the total mercury release amount and Hg⁰ proportion. The increase in the H₂O/CO₂ ratio of gasification mediums in the FR was beneficial for the increase in the total mercury release amount and Hg⁰ proportion. A higher O₂ concentration in reaction atmosphere in AR had a negligible effect on the total mercury release amount, but a positive effect on Hg⁰ oxidization.     

降水量与城市大气环境关系——以113个环保重点城市为例

为研究降水量与大气污染物之间的关系,依据2017年全国113个环保重点城市大气质量数据,得出城市聚类空间分布规律及两者之间线性拟合方程。基于南北降水量分布特性与城市空气污染指数,采用模糊聚类法对具有不同亲疏程度的城市进行类别划分,运用Spearman相关性与拟合方程对大气污染特征值与降水量进行分析。结果表明：随着聚类种数增多,城市聚集在空间分布上由“环环相套”发展为“依流域分布”,降水量与大气污染物浓度呈现负向关联性,晋冀鲁豫陕省份污染最严重。采用Kolmogorov-Smirnov检验法,得出NO₂、O₃、PM_2.5总体分布符合正态分布,SO₂、PM₁₀、CO既不符合正态分布,也不符合均匀、指数分布,它们与降水量的相关系数为：-0.316、-0.238、-0.332、-0.617、-0.574、-0.695;线性拟合方程系数处于 [-0.031, -0.008] 之间,降水量与大气污染物浓度之间负相关性明显。研究结果有助于了解和认识降水量对城市大气环境变化的影响。     

三级AO耦合工艺低温污水处理脱氮机理

采用分段进水三级AO耦合流离生化工艺处理低温废水,在温度为（10±1）℃条件下,控制HRT为8h,进水流量分配比为3：2：1,污泥回流比为50%,考察耦合工艺对低温污水中污染物的去除效果、反应器内污染物变化规律、各级氮去除规律及系统硝化反硝化性能.研究表明：耦合工艺COD及NH₄⁺-N去除效率均超过90%,TN及TP去除效率达到80%,反应器内生物膜污泥浓度在400~800mg/L之间,系统各级NH₄⁺-N去除率均超过80%,缺氧反硝化脱氮率及好氧同步硝化反硝化脱氮率分别为50.15%和26.05%.受底物浓度及功能菌群数量影响,系统第二级比硝化速率及比反硝化速率均最高.     

Emissions of intermediate volatility organic compound from waste cooking oil biodiesel and marine gas oil on a ship auxiliary engine

Ship auxiliary engines contribute large amounts of air pollutants when at berth.Biodiesel,including that from waste cooking oil(WCO),can favor a reduction in the emission of primary pollutant when used with internal combustion engines.This study investigated the emissions of gaseous intermediate-volatile organic compounds(IVOCs) between WCO biodiesel and marine gas oil(MGO) to further understand the differences in secondary organic aerosol(SOA) production of exhausts.Results revealed that WCO exhaust exhibited similar IVOC composition and volatility distribution to MGO exhaust,despite the differences between fuel contents.While WCO biodiesel could reduce IVOC emissions by 50% as compared to MGO,and thus reduced the SOA production from IVOCs.The compositions and volatility distributions of exhaust IVOCs varied to those of their fuels,implying that fuel-component-based SOA predicting model should be used with more cautions when assessing SOA production of WCO and MGO exhausts.WCO biodiesel is a cleaner fuel comparing to conventional MGO on ship auxiliary engines with regard to the reductions in gaseous IVOC emissions and corresponding SOA productions.Although the tests were conducted on test bench,the results could be considered as representative due to the widely applications of the test engine and MGO fuel on real-world ships.     

Performance, microbial community and inhibition kinetics of long-term Cu2+ stress on an air-lift nitritation reactor with self-recirculation

Biological nitrogen removal process could be affected due to the presence of heavy metals owing to their toxicity and accumulation in the sludge.In this study,the impact of Cu~(2+)shock on a long-term nitritation operation was investigated in an air-lift reactor with selfrecirculation.Both the dynamics of microbial community and inhibition kinetics under Cu~(2+) stress were ascertained.The results showed that Cu~(2+) exerted severe inhibition on nitritation performance of an air-lift reactor(ALR) at 25 mg/L.The corresponding NH_4~+-N removal efficiency decreased to below 50%,which was mainly due to the variation of microbial community structure,especially the inhibition of nitrifiers like Nitrosomonas(the relative abundance decreased from 30% to 1% after Cu~(2+)inhibition).Kinetic parameters were obtained and compared after fitting the Haldane model.The long-term Cu~(2+) stress on the ALR aggravated the ammonium affinity and the resistance to substrate self-inhibition of the nitritation sludge,but reduced the resistance to Cu~(2+) inhibition.Furthermore,Cu~(2+)acted as uncompetitive inhibitor on nitritation process.Our results provide new insights into the nitritation characteristics under long-term Cu~(2+) stress.     

Degradation of kanamycin from production wastewater with high-concentration organic matrices by hydrothermal treatment

It is known that many kinds of fermentative antibiotics can be removed by temperature-enhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics. However, a few aminoglycosides are hard to hydrolyze below 100°C because of their stability expressed by high molecular energy gap (ΔE). Herein, removal of hard-to-hydrolyze kanamycin residue from production wastewater by hydrothermal treatment at subcritical temperatures was investigated. The results showed the reaction temperature had a significant impact on kanamycin degradation. The degradation half-life (t_1/2) was shortened by 87.17-fold when the hydrothermal treatment temperature was increased from 100°C to 180°C. The t_1/2 of kanamycin in the N₂ process was extended by 1.08-1.34-fold compared to that of the corresponding air process at reaction temperatures of 140-180°C, indicating that the reactions during hydrothermal treatment process mainly include oxidation and hydrolysis. However, the contribution of hydrolysis was calculated as 75%-98%, which showed hydrolysis played a major role during the process, providing possibilities for the removal of kanamycin from production wastewaters with high-concentration organic matrices. Five transformation products with lower antibacterial activity than kanamycin were identified using UPLC-QTOF-MS analysis. More importantly, hydrothermal treatment could remove 97.9% of antibacterial activity (kanamycin EQ, 1,109 mg/L) from actual production wastewater with COD_Cr around 100,000 mg/L. Furthermore, the methane production yield in anaerobic inhibition tests could be increased about 2.3 times by adopting the hydrothermal pretreatment. Therefore, it is concluded that hydrothermal treatment as a pretreatment technology is an efficient method for removing high-concentration hard-to-hydrolyze antibiotic residues from wastewater with high-concentration organic matrices.     

改性活性炭对内分泌干扰物的吸附效能与机制

为提高活性炭对内分泌干扰物的吸附效率,分别采用混合酸溶液,氨水,KMnO₄溶液和表面活性剂溶液对活性炭进行改性.采用比表面积及孔隙度分析仪、扫描电子显微镜（SEM）、傅里叶红外光谱（FT-IR）和Boehm滴定法对改性后活性炭表面化学性质及孔隙特征的变化进行评价.通过静态吸附实验确定活性炭的最佳改性方法,并对改性后活性炭吸附机理进行探讨.实验结果表明,KMnO₄改性活性炭（AC-K）表现出最佳的污染物吸附性能,其对邻苯二甲酸二丁酯（DBP）、阿特拉津（Atrazine）和磺胺甲恶唑（SMZ）的去除率分别可达到94.5%、93.8%和95.5%,且吸附过程符合二级动力学方程和D-R模型.由模型计算结果可知,AC-K对目标污染物的吸附速率明显加快,其中对Atrazine的二级吸附速率常数是AC的1.75倍.AC-K对DBP、Atrazine和SMZ的理论饱和吸附量也分别比改性前分别提高了42.2%、629%和122%.经KMnO₄改性后,活性炭的吸附机制由物理吸附占主导,转化为离子交换吸附.     

臭氧氧化工艺对污水处理厂二级出水的处理特性

城镇污水处理厂深度处理单元采用臭氧氧化和臭氧催化氧化工艺可对溶解性难降解有机物进行强化去除。针对臭氧氧化的选择性和臭氧催化氧化去除COD的稳定性,以污水处理厂二级出水为研究对象进行臭氧氧化小试和中试试验,考察不同进水水质情况下臭氧氧化的效果,臭氧氧化后污水可生化性和NH₃-N的变化情况以及臭氧催化氧化去除COD的稳定性。研究结果表明:臭氧氧化对不同水质进水COD的去除效果差异较大,对含有较多饱和有机酸的污水处理效果有限,且臭氧氧化处理后污水BOD₅和NH₃-N均未升高。臭氧催化氧化去除COD的效果与催化剂的吸附饱和程度相关。因此,建议设计城镇污水处理厂臭氧氧化和臭氧催化氧化工艺前需进行小试实验明确对COD的去除效果,臭氧催化氧化小试实验需进行90 d以上或试验至臭氧催化剂达到吸附饱和,不建议在臭氧氧化工艺后增设生物滤池和曝气生物滤池。