碳中和时代下我国能量自给型污水处理厂发展方向及工程实践

基于碳中和背景及污水处理可持续、低碳运行理念,分析了我国污水处理厂不同水质、工艺类型、规模等条件下的能源消耗及能源回收特点,提出了以“碳改向技术+低耗高效复合脱氮技术+污泥厌氧共消化技术+污水热能回收技术+节能降耗技术”的污水处理新模式是实现我国能源自给型污水处理厂的关键,并提出我国污水处理厂实现碳中和应分为“完全能源自给”及“能源供应工厂”两个目标.此外,对基于此背景下建设的北京某再生水厂的理论能源自给情况进行了分析,结果表明,通过节能降耗、引入外源有机物、污水源热泵回收等措施,北京某再生水厂能源自给率由12.2%分别提高至17.1%、21.6%、84.7%.     

g-C3N4/TiO2纳米管阵列光阳极的制备及其光电催化降解邻氯硝基苯

采用阳极氧化-涂覆煅烧法成功制备了g-C₃N₄/TiO₂纳米管阵列（g-C₃N₄/TNAs）光阳极,并通过扫描电镜、X射线衍射仪、X射线光电子能谱仪、紫外可见漫反射光谱仪、光致发光光谱仪和电化学工作站等表征分析了g-C₃N₄/TNAs光阳极的形貌、晶形结构、光学特性和光电化学性能.表征结果证实,g-C₃N₄的引入通过缩小禁带宽度扩宽了TNAs的可见光响应范围,提高了光电流密度和光生电子寿命,促进了光生电子和空穴的分离.g-C₃N₄/TNAs光阳极在光电催化体系内对邻氯硝基苯（o-CNB）的降解效率高于其在光催化和电催化体系中对o-CNB的降解效率,且具有良好的稳定性和可重复性.活性物质捕获实验、电子自旋共振测试和能带结构分析表明,g-C₃N₄/TNAs光阳极中TNAs和g-C₃N₄之间存在Z型异质结相互作用机制.在光电催化体系内降解o-CNB的主要活性物质是^?O₂^-、^?OH和光生空穴,而光生电子是次要的活性物质.     

Grazing greatly reduces the temporal stability of soil cellulolytic fungal community in a steppe on the Tibetan Plateau

Excessive livestock grazing degrades grasslands ecosystem stability and sustainability by reducing soil organic matter and plant productivity. However, the effects of grazing on soil cellulolytic fungi, an important indicator of the degradation process for soil organic matter, remain less well understood. Using T-RFLP and sequencing methods, we investigated the effects of grazing on the temporal changes of cellulolytic fungal abundance and community structure in dry steppe soils during the growing months from May to September, on the Tibetan Plateau using T-RFLP and sequencing methods. The results demonstrated that the abundance of soil cellulolytic fungi under grazing treatment changed significantly from month to month, and was positively correlated with dissolved organic carbon (DOC) and soil temperature, but negatively correlated with soil pH. Contrastingly, cellulolytic fungal abundance did not change within the fencing treatment (ungrazed conditions). Cellulolytic fungal community structure changed significantly in the growing months in grazed soils, but did not change in fenced soils. Grazing played a key role in determining the community structure of soil cellulolytic fungi by explaining 8.1% of the variation, while pH and DOC explained 4.1% and 4.0%, respectively. Phylogenetically, the cellulolytic fungi were primarily affiliated with Ascomycota (69.65% in relative abundance) and Basidiomycota (30.35%). Therefore, grazing substantially reduced the stability of soil cellulolytic fungal abundance and community structure, as compared with the fencing treatment. Our finding provides a new insight into the responses of organic matter-decomposing microbes for grassland managements.     

Relationships between regulated DBPs and emerging DBPs of health concern in U.S. drinking water

A survey was conducted at eight U.S. drinking water plants, that spanned a wide range of water qualities and treatment/disinfection practices. Plants that treated heavily-wastewater-impacted source waters had lower trihalomethane to dihaloacetonitrile ratios due to the presence of more organic nitrogen and HAN precursors. As the bromide to total organic carbon ratio increased, there was more bromine incorporation into DBPs. This has been shown in other studies for THMs and selected emerging DBPs (HANs), whereas this study examined bromine incorporation for a wider group of emerging DBPs (haloacetaldehydes, halonitromethanes). Moreover, bromine incorporation into the emerging DBPs was, in general, similar to that of the THMs. Epidemiology studies that show an association between adverse health effects and brominated THMs may be due to the formation of brominated emerging DBPs of heath concern. Plants with higher free chlorine contact times before ammonia addition to form chloramines had less iodinated DBP formation in chloraminated distribution systems, where there was more oxidation of the iodide to iodate (a sink for the iodide) by the chlorine. This has been shown in many bench-scale studies (primarily for iodinated THMs), but seldom in full-scale studies (where this study also showed the impact on total organic iodine. Collectively, the THMs, haloacetic acids, and emerging DBPs accounted for a significant portion of the TOCl, TOBr, and TOI; however, ∼50% of the TOCl and TOBr is still unknown. The correlation of the sum of detected DBPs with the TOCl and TOBr suggests that they can be used as reliable surrogates.     

Wall losses of oxygenated volatile organic compounds from oxidation of toluene: Effects of chamber volume and relative humidity

Vapor wall losses can affect the yields of secondary organic aerosol. The effects of surface-to-volume (S/V) ratio and relative humidity (RH) on the vapor-wall interactions were investigated in this study. The oxygenated volatile organic compounds (OVOCs) were generated from toluene-H₂O₂ irradiations. The average gas to wall loss rate constant (k_gw) of OVOCs in a 400 L reactor (S/V = 7.5 m⁻¹) is 2.47 (2.41 under humid conditions) times higher than that in a 5000 L reactor (S/V = 3.6 m⁻¹) under dry conditions. In contrast, the average desorption rate constant (k_wg) of OVOCs in 400 L reactor is only 1.37 (1.20 under humid conditions) times higher than that in 5000 L reactor under dry conditions. It shows that increasing the S/V ratio can promote the wall losses of OVOCs. By contrast, the RH effect on k_gw is not prominent. The average k_gw value under humid conditions is almost the same as under dry conditions in the 400 L (5000 L) reactor. However, increasing RH can decrease the desorption rates. The average k_wg value under dry conditions is 1.45 (1.27) times higher than that under humid conditions in the 400 L (5000 L) reactor. The high RH can increase the partitioning equilibrium timescales and enhance the wall losses of OVOCs.     

不同施肥措施下长江经济带地区农田土壤有机碳含量的变化分析

收集整理1992年1月至2022年5月长江经济带地区长期定位施肥试验文献,提取并整合了其中农田土壤有机碳的资料.采用归一化处理和变化速率的分析方法,研究长期不同施肥措施下长江经济带地区农田土壤有机碳含量的总体变化,并比较3种耕作模式及不同土壤类型下土壤有机碳含量的变化差异,判断分析试验持续年限长短对土壤有机碳动态的影响.结果表明,在长期不同施肥措施下,我国长江经济带地区农田土壤有机碳含量整体呈上升趋势,无机氮肥磷肥配施(NP)、无机氮磷钾肥配施(NPK)、单独施用有机肥(O)和有机无机肥配施(NPKO)处理均能增加农田土壤的有机碳含量,其中以NPKO处理为最大,而单独施用无机氮肥(N)则会降低土壤有机碳含量.旱田、水田和水旱轮作农田土壤有机碳含量变化速率分别为0.22、 0.24和0.16g·(kg·a)^-1,3种耕作模式在土壤固碳效果方面并无显著性差异.O和NPKO处理下所带来的有机碳相对快速增加效应在旱田土壤中的持续年限最高不超过28 a,而在水田及水旱轮作土壤中依然可以持续到28 a以上.在不同的土壤类型下,土壤有机碳含量的变化速率存在着一定的差异,平均有机...     

气相色谱法测定室内空气中挥发性卤代烃

建立了活性炭吸附-溶剂解吸-气相色谱测定室内空气中7种挥发性卤代烃的分析方法。样品经活性炭采样管富集后,用二硫化碳解吸,Agilent HP-1色谱柱分离,使用带有电子捕获检测器的气相色谱仪测定,以保留时间定性,外标法定量。当采样体积为10 L时,方法检出限范围是0.03~0.18 g/m3,加标回收率在72%~114%之间,相对标准偏差小于15%。结果表明,该方法可以应用于室内空气中痕量挥发性卤代烃样品的检测分析。     

控释尿素不同施用条件下冬小麦产量和氮素利用效应

采用田间试验方法研究了控释尿素不同施用条件对冬小麦产量、氮素利用和经济效益的影响。试验共设7个处理,即CK （空白处理,不施氮肥）、100%PU10/0（普通尿素全量基施,N 240 kg＆#183;hm-2）、100%PU6/4（60%的普通尿素基施、40%的普通尿素于拔节期追施,N 240 kg＆#183;hm-2）、80%PU6/4（60%的普通尿素基施、40%的普通尿素于拔节期追施,N 192 kg＆#183;hm-2）、100%CRU（全量树脂包膜控释尿素基施,N 240 kg＆#183;hm-2）、80%CRU（80%树脂包膜控释尿素基施,N 192 kg＆#183;hm-2）和40%CRU＋40%PU（40%树脂包膜控释尿素＋40%的普通尿素基施,N 192 kg＆#183;hm-2）。结果表明,无论是产量效应还是氮素利用效应,树脂包膜控释尿素（CRU）处理总体优于普通尿素（PU）处理,尤其树脂包膜控释尿素和普通尿素配施（40%CRU＋40%PU）效果最佳,以7709 kg＆#183;hm-2的产量、36.44%的氮肥吸收利用率、15946元＆#183;hm-2的相对净收入达到处理间最高水平。该处理在减少氮素投入量的情况下,不仅促进了冬小麦增产,而且显著提高了肥料的利用率,拥有较高的产投比。因此,树脂包膜控释尿素和普通尿素的配施处理（40%CRU＋40%PU）是本试验条件下最优的氮肥处理。     

Application of an enzyme-linked immunosorbent assay for the detection of clenbuterol residues in swine urine and feeds

The present study outlines applications of an enzyme-linked immunosorbent assay (ELISA) for the analysis of clenbuterol residues. Antisera were raised from rabbits immunized with diazotized clenbuterol-bovine serum albumin (BSA) conjugate. The assay was specific to clenbuterol with a half-maximum inhibition concentration (IC₅₀) of 1.8 ng/mL and 2.5 ng/mL in blank swine urine and phosphate buffer solution, respectively. The assay had high cross-reactivity (86%) with mabuterol, but low with other adrenergic agonists and antagonists. The average recovery of clenbuterol, as measured with the ELISA, ranged from 90% to 112% in swine urine samples and from 86% to 95% in feeds, respectively. This new assay was compared with commercial ELISA test kits. An excellent correlation (r ² = 0.98) between the two methods and satisfactory recoveries suggest that the new assay can be suitable for the determination of clenbuterol residues in real samples. The assay was used to analyze clenbuterol residues in 103 swine urine samples and 68 feed samples collected from northern China. Approximately 50% of the urine samples and 25% of the feed samples analyzed were found positive (concentration of clenbuterol ≥ 1 ppb). The results indicate that clenbuterol was misused in some of the areas surveyed.     

Communities of different plant diversity respond similarly to drought stress: experimental evidence from field non-weeded and greenhouse conditions

Accelerating rate of species loss has prompted researchers to study the role of species diversity in processes that control ecosystem functioning. Although negative impact of species loss has been documented, the evidence concerning its impact on ecosystem stability is still limited. Here, we studied the effects of declining species and functional diversity on plant community responses to drought in the field (open to weed colonization) and greenhouse conditions. Both species and functional diversity positively affected the average yields of field communities. However, this pattern was similar in both drought-stressed and control plots. No effect of diversity on community resistance, biomass recovery after drought and resilience was found because drought reduced biomass production similarly at each level of diversity by approximately 30?%. The use of dissimilarity (characterized by Euclidean distance) revealed higher variation under changing environments (drought-stressed vs. control) in more diverse communities compared to less species-rich assemblages. In the greenhouse experiment, the effect of species diversity affected community resistance, indicating that more diverse communities suffered more from drought than species-poor ones. We conclude that our study did not support the insurance hypothesis (stability properties of a community should increase with species richness) because species diversity had an equivocal effect on ecosystem resistance and resilience in an environment held under non-weeded practice, regardless of the positive relationship between sown species diversity and community biomass production. More species-rich communities were less resistant against drought-stressed conditions than species-poor ones grown in greenhouse conditions.