Physico-chemical characterization of Residual Household Waste for energy recovery in insular territories: Case study of Reunion Island

Waste-to-energy is a promising approach to face the current challenge of waste overproduction in Reunion Island, a French territory. In this particular context of an isolated and tropical territory, it is essential to study the properties of potential feedstocks to choose the most appropriate conversion process. This article reports on the composition of Residual Household Waste from Reunion Island and its physico-chemical parameters. Twelve representative samples of Residual Household Waste were subjected to thermal and elemental analysis. The results showed that their composition had a significant influence on the physico-chemical properties, including calorific value. Residual Household Waste from the selective sorting (rich in wood, plastic, and sanitary textiles) as well as dry mixed RHW are the most interesting for energy recovery. Due to their high volatile matter and high carbon content, and their low moisture content, these types of waste have a high calorific value exceeding 18 MJ/kg. Furthermore, the RHW sample comply with the environmental and health criteria applied by French regulations concerning halogen and heavy metal. Thus, it seems that Residual Household Waste can be an alternative to conventional fuels used in incineration or pyro-gasification processes. However, the study also points the need for a pre-treatment process for these wastes. Indeed, it is necessary to sort them correctly in order to avoid the risks of pollution and important maintenance. And more importantly, drying beforehand is unavoidable to improve combustibility and obtain optimal energy conversion.     

A new prediction method of industrial atmospheric pollutant emission intensity based on pollutant emission standard quantification

● Established a quantification method of pollutant emission standard. ● Predicted the SO₂ emission intensity of single coking enterprises in China. ● Evaluated the influence of pollutant discharge standard on prediction accuracy. ● Analyzed the SO₂ emissions of Chinese provincial and municipal coking enterprises. Industrial emissions are the main source of atmospheric pollutants in China. Accurate and reasonable prediction of the emission of atmospheric pollutants from single enterprise can determine the exact source of atmospheric pollutants and control atmospheric pollution precisely. Based on China’s coking enterprises in 2020, we proposed a quantitative method for pollutant emission standards and introduced the quantification results of pollutant emission standards (QRPES) into the construction of support vector regression (SVR) and random forest regression (RFR) prediction methods for SO₂ emission of coking enterprises in China. The results show that, affected by the types of coke ovens and regions, China’s current coking enterprises have implemented a total of 21 emission standards, with marked differences. After adding QRPES, it was found that the root mean squared error (RMSE) of SVR and RFR decreased from 0.055 kt/a and 0.059 kt/a to 0.045 kt/a and 0.039 kt/a, and theR² increased from 0.890 and 0.881 to 0.926 and 0.945, respectively. This shows that the QRPES can greatly improve the prediction accuracy, and the SO₂ emissions of each enterprise are highly correlated with the strictness of standards. The predicted result shows that 45% of SO₂ emissions from Chinese coking enterprises are concentrated in Shanxi, Shaanxi and Hebei provinces in central China. The method created in this paper fills in the blank of forecasting method of air pollutant emission intensity of single enterprise and is of great help to the accurate control of air pollutants.     

微塑料与有机污染物的相互作用研究进展

微塑料(粒径小于5 mm的塑料)作为海洋中一种新型的污染物正受到越来越多的关注。微塑料在全球多个海域均有检出,根据其来源分为原生微塑料和次生微塑料。原生微塑料由人工直接制造所得,常见于日常生活用品中;次生微塑料由大块塑料制品长期风化、磨损和光解形成。塑料自身含有多种有机添加剂,不断向环境中释放,污染海洋环境;微塑料表面还可吸附有机污染物,此吸附作用受两者的物理化学性质和环境条件影响,吸附污染物后的微塑料生物毒性增强。另外,聚合物复合光催化材料可加快有机污染物如染料的光降解反应速率,因而微塑料可能会促进有机污染物的光解。针对目前微塑料对有机物光降解的贡献、机理鲜见研究的问题,未来应加强以下3方面的研究:(1)微塑料对不同有机污染物光降解是否存在影响?(2)微塑料类型、尺寸以及反应条件对有机污染物光降解如何影响?(3)微塑料对有机污染物光降解影响的内在机制是什么?     

一种新型铋基光催化剂的合成及其可见光催化性能

采用水热法合成铋基光催化剂Bi4VO8Br,通过X-射线粉末衍射、扫描电镜等手段对其进行表征.选择甲基橙为目标降解物来评价不同条件下合成的Bi4VO8Br在可见光下的光催化活性,发现pH 3、反应时间15 h、反应温度160℃为材料水热合成的最佳条件.考察了Bi4VO8Br在可见光及紫外光下对几种农药和增塑剂的光催化降解性能,显示了Bi4VO8Br对不易光解的含苯环有机物的可见光高活性.五氯酚的光催化过程影响因素优化结果表明,可见光和紫外光分别照射120 min和20 min,其降解率分别达到97％和99％,Bi4VO8Br表面上活性基团的捕获即空穴的氧化作用是主要反应原理.     

微塑料对环境中有机污染物吸附解吸的研究进展

微塑料已成为新的全球性环境污染问题。作为强吸附剂,微塑料可以吸附共存的有机污染物,进而改变其环境行为和毒性;也可以通过解吸作用促进污染物在不同介质中的迁移。因而,微塑料与有机污染物的相互作用强度和机理是全面评估两者的环境风险和深度研究微塑料毒性机制的必要信息。目前微塑料研究处于快速发展的起始阶段,加之微塑料本身成分、粒径、表面风化情况的复杂性及共存有机污染物的多样性使两者的相互作用十分复杂,亟需理清微塑料吸附解吸作用的影响因素和相关机制。因而,本文详细综述了微塑料对有机污染物吸附解吸作用的研究进展,并着重从微塑料性质(成分、粒径和表面风化)、有机污染物性质和水环境介质性质方面探讨了吸附的影响因素和相互作用机制,希望为微塑料吸附有机污染物及吸附的后续影响研究提供借鉴与参考。     

浅谈验收监测中水污染物排放总量的核算与评价

简述了水污染物排放总量核算与评价的基本概念。结合实际工作经验,对新建项目水污染物排放总量核算与评价、改扩建项目水污染物排放总量核算与评价分别进行分析与探讨,并提出了核算与评价方法和建议。     

Human milk contamination by nine organochlorine pesticide residues (OCPs)

Abstract

Organochlorine pesticides (OCPs) are widely used around the world as insecticides, herbicides, fungicides, nematicides, and rodenticides. Despite banned in Brazil, the usage remains occurring in many countries. The persistence and extreme mobility of OCPs contribute to the contamination of the environment and the human body. The OCPs bioaccumulation in adipose tissue triggers the excretion into human milk during breastfeeding. Hence, the present study determined eighteen OCPs residues in the breast milk of mothers from the Western Region of Bahia State, Brazil. Nine different residue species were found, including beta-Hexachlorocyclohexane (9.24?±?0.00?ng g^?1 fat), delta- Hexachlorocyclohexane (22.15?±?10.48?ng g^?1 fat), Heptachlor (58.08?±?74.13?ng g^?1 fat), Aldrin (142.65?±?50.65?ng g^?1 fat), Dieldrin (774.62?±?472.68?ng g^?1 fat), Endosulfan I (408.44?±?245.51?ng g^?1 fat), Dichloro-diphenyl-dichloro-ethylene (29.17?±?22.42?ng g^?1 fat), Dichloro-diphenyl-trichloro-ethane (28.87?±?0.00?ng g^?1 fat) and Methoxychlor (1699.67?±?797.43?ng g^?1 fat). The Methoxychlor presence in all samples may reveal a recent exposure, while Dieldrin and Endosulfan I analyses can point to distant past exposure.     

宁东能源化工基地核心区表层土壤酚类污染物的污染评价、空间分布及来源解析

采集了宁东能源化工基地核心区的146个表层土壤样品,检测了6种优控酚类污染物。运用单因子污染指数、内梅罗综合污染指数和致癌风险指数评价了酚类污染物的污染程度及健康风险。借助主成分分析和绝对主成分分数-多元线性回归受体模型,结合地统计学方法,对酚类污染物的空间分布及来源进行了分析。结果显示：2,4-二氯酚和2,4,6-三氯酚处于清洁水平,五氯酚在部分区域为重度污染;苯酚、2,4-二氯酚、2,4,6-三氯酚为可接受风险,五氯酚在部分区域为不可接受风险;苯酚、4-硝基酚、间-甲酚和2,4-二氯酚的来源以交通源为主,2,4,6-三氯酚和五氯酚的来源以工业活动源为主。     

模糊综合评判法在渭河水质评价中的应用研究

渭河是陕西省的第一大河流,准确的水质评价是治理渭河水体污染的重要前提。本文采用模糊变换原理和最大隶属度原则,运用模糊综合评判法对渭河潼关吊桥断面2012年的监测数据进行了全面评价。结果表明该断面春、夏、秋、冬四个季度的水质污染级别分别为:Ⅴ类(严重污染)、Ⅰ类(未污染)、Ⅳ类(重污染)和Ⅴ类(严重污染),主要污染物为NH3-N。与传统的单因子评价法相比,该方法能更全面合理地反映水质情况。     

Efficient dechlorination of chlorinated solvent pollutants under UV irradiation by using the synthesized TiO2 nano-sheets in aqueous phase

Titanium dioxide(TiO2), which is the widely used photo-catalyst, has been synthesized by simple hydrothermal solution containing tetrabutyl titanate and hydrofluoric acid. The synthesized product has been applied to photo-degradation in aqueous phase of chlorinated solvents, namely tetrachloroethene(PCE), trichloroethene(TCE) and 1,1,1-trichloroethane(TCA). The photo-degradation results revealed that the degradation of these harmful chemicals was better in UV/synthesized TiO2 system compared to UV/commercial P25 system and UV only system. The photo-catalytic efficiency of the synthesized TiO2 was 1.4, 1.8 and 3.0 folds higher compared to the commercial P25 for TCA, TCE and PCE degradation, respectively. Moreover, using nitrobenzene(NB) as a probe of hydroxyl radical(.OH), the degradation rate was better over UV/synthesized TiO2, suggesting the high concentration of.OH generated in UV/synthesized TiO2system. In addition,.OH concentration was confirmed by the strong peak displayed in EPR analysis over UV/synthesized TiO2system. The characterization result using XRD and TEM showed that the synthesized TiO2 was in anatase form and consisted of well-defined sheet-shaped structures having a rectangular outline with a thickness of 4 nm, side length of 50 nm and width of 33 nm and a surface 90.3 m2/g. XPS analysis revealed that ≡Ti-F bond was formed on the surface of the synthesized TiO2. The above results on both photocatalytic activity and the surface analysis demonstrated the good applicability of the synthesized TiO2 nano-sheets for the remediation of chlorinated solvent contaminated groundwater.