Full-scale blending treatment of fresh MSWI leachate with municipal wastewater in a wastewater treatment plant

Fresh leachate, generated in municipal solid waste incineration (MSWI) plants, contains various pollutants with extremely high strength organics, which usually requires expensive and complex treatment processes. This study investigated the feasibility of blending treatment of MSWI leachate with municipal wastewater. Fresh MSWI leachate was pretreated by coagulation–flocculation with FeCl₃ 2 g/L and CaO 25 g/L, plate-and-frame filter press, followed by ammonia stripping at pH above 12. After that, blending treatment was carried out in a full-scale municipal wastewater treatment plant (WWTP) for approximately 3 months. Different operational modes consisting of different pretreated leachate and methanol addition levels were tested, and their performances were evaluated. Results showed that throughout the experimental period, monitored parameters in the WWTP effluent, including COD (<60 mg/L), BOD₅ (<20 mg/L), ammonium (<8 mg/L), phosphorus (<1.5 mg/L) and heavy metals, generally complied with the Chinese sewage discharged standard. Under the experimental conditions, a certain amount of methanol was needed to fulfill TN removal. An estimation of the operation cost revealed that the expenditure of blending treatment was much lower than the total costs of respective treatment of MSWI leachate and municipal wastewater. The outcomes indicated that blending treatment could not only improve the treatability of the MSWI leachate, but also reduce the treatment cost of the two different wastewaters.     

TiO2/H2O2/UV和TiO2/O3/UV降解对氯苯甲酸和喹啉的试验研究

主要叙述TiO2/H2O2/UV和TiO2/O3/UV体系降解对氯苯甲酸（4-CBA）和喹啉的试验研究.研究表明,（1）在TiO2/H2O2/UV体系里目标物降解速度先随过氧化氢投加量的增加而提高,但超过一定浓度之后便开始下降;（2）在TiO2/O3/UV体系中,目标降解物的反应速度都非常快,且臭氧浓度高的时候降解速度更快;（3）二氧化钛催化剂在TiO2/O3/UV体系中作为积极因素有助于提高反应速率,而在TiO2/H2O2/UV体系是消极因素,会降低反应速率.     

污泥果肥利用中重金属迁移特征研究

为了厦门城市污泥的安全利用,将石渭头污水处理厂污泥经过好氧堆肥后施用于柚子树,对重金属元素在土壤、树叶及果肉中的迁移特征进行了研究。结果表明：Cd在土壤中的富集能力强;重金属元素从土壤向树叶迁移累积能力比向果肉的大得多,污泥肥料不能用于叶类食用植物的施用;Cr向树叶、Ni向果肉的迁移累积能力强;泥肥的施用加重了土壤中Cd的污染,提高了Cr向树叶、Ni向果肉的迁移能力;污泥果肥利用需降低Ni的浓度,对污泥中含量较高的Cu、Zn、Ni、Cr和Cd需进行跟踪检测。     

Long-term impacts of reservoir operation on the spatiotemporal variation in nitrogen forms in the post-Three Gorges Dam period (2004–2016)

Environmental Science and Pollution Research - Nitrogen (N) is an essential nutrient limiting life, and its biochemical cycling and distribution in rivers have been markedly affected by river...     

不同干扰方式对内蒙古典型草原土壤有机碳和全氮的影响

为准确把握草原生态保护与修复工程的实施效果,并为北方草地生态保护和优化管理提供有效的科学支持,选择内蒙古典型草原退牧还草工程区为研究对象,采用野外成对取样(围栏内-围栏外)与室内分析相结合的方法,研究了休牧、补播和自由放牧3种人为干扰方式对土壤容重、含水量、有机碳和全氮含量的影响。结果表明:在0~30 cm土层,随深度的增加,不同干扰方式对各指标的影响不同,但总体上草原土壤含水量、有机碳和全氮含量表现为补播﹥休牧﹥自由放牧(P0.05);土壤容重为自由放牧休牧补播(P0.05)。随土层深度增加,除土壤容重无显著变化外(P0.05),土壤有机碳和全氮含量均呈现显著下降(P0.05);土壤含水量则相反,其中,补播处理降幅最小,自由放牧处理降幅最大。0~30 cm各土层土壤容重与土壤含水量、土壤有机碳和全氮含量都成极显著负相关关系(P0.000 1),而土壤含水量、有机碳和全氮3项指标间相互成显著正相关关系(P0.000 1)。综上所述,不同干扰方式对草地土壤理化性状有明显影响,自由放牧加速了草地土壤有机碳和全氮的损失,而补播和休牧对遏制草地退化、恢复草地功能起到了积极的作用。     

Label-free colorimetric nanosensor with improved sensitivity for Pb2+ in water by using a truncated 8–17 DNAzyme

• Unmodified-AuNP based, colorimetric nanosensor was constructed for Pb²⁺ detection. • 5-nucleotide truncation in DNAzyme made complete substrate detachment upon Pb²⁺. • Ultrasensitive and selective detection of Lead (II) was achieved with 0.2×10^-9 mol/L LOD. Water pollution accidents, such as the Flint water crisis in the United States, caused by lead contamination have raised concern on the safety of drinking water distribution systems. Thus, the routine monitoring of lead in water is highly required and demands efficient, sensitive, cost-effective, and reliable lead detection methods. This study reports a label-free colorimetric nanosensor that uses unmodified gold nanoparticles (AuNPs) as indicators to enable rapid and ultra-sensitive detection of lead in environmental water. The 8–17 DNAzyme was truncated in this study to facilitate the detachment of single-stranded DNA fragments after substrate cleavage in the presence of Pb²⁺. The detached fragments were adsorbed over AuNPs and protected against salt concentration-induced aggregation. Accordingly, high Pb²⁺ would result in rapid color change from blue to pink. The established sensing principle achieved a sensitive limit of detection of 0.2×10^-9 mol/L Pb²⁺, with a linear working range of two orders of magnitude from 0.5×10^-9 mol/L to 5×10^-9 mol/L. The selectivity of the nanosensor was demonstrated by evaluating the interfering metal ions. The developed nanosensor can serve as a substitute for the rapid analysis and monitoring of trace lead levels under the drinking water distribution system and even other environmental water samples.     

Electrochemical analysis of trifluralin using a nanostructuring electrode with multi-walled carbon nanotubes

The electroanalytical behaviors of the endocrine-disrupting chemical trifluralin have been studied at a nanostructuring electrode. The nanostructuring electrode was fabricated by coating a uniform multi-wall carbon nanotubes/dihexadecyl hydrogen phosphate (MWNTs/DHP) film on glassy carbon electrode (GCE). The reduction peak currents of trifluralin increased remarkably and the reduction peak potential shifted positively at the nanostructuring electrode, compared with that at a bare GCE. The results showed that this nanostructuring electrode exhibited excellent enhancement effects on the electrochemical reduction of trifluralin. Consequently, a simple and sensitive electroanalytical method was developed for the determination of trifluralin. Under optimal conditions, a linear response of trifluralin was obtained in the range from 5.0 × 10⁻⁹ to 6.0 × 10⁻⁶ mol L⁻¹ (r = 0.998) and with a limit of detect (LOD) of 2.0 × 10⁻⁹ mol L⁻¹. The proposed procedure was successfully applied to determine trifluralin in soil samples with satisfactory results.     

动力学荧光分析法测定水样中的邻苯二酚

在稀H2SO4溶液介质和90℃下,邻苯二酚为活化剂、钒(V)为催化剂的KIO4氧化罗丹明B的活化体系中,该体系的荧光猝灭值与邻苯二酚的用量呈线形关系,据此建立了测定邻苯二酚的动力学荧光分析新方法.该方法的线性范围为0.3～320.0μg/L,检出限为7.21μg/L,对200.00μg/L的邻苯二酚溶液测定11次的相对标准偏差为2.25%.该法适用于环境样品中的邻苯二酚测定.     

Acute toxicity assessment of drinking water source with luminescent bacteria: Impact of environmental conditions and a case study in Luoma Lake,East China

• Acute toxicity assessment was conducted in Luoma lake watershed, East China. • Impacts of environmental factors on the toxicity testing was fully evaluated. • Dissolve oxygen had a weak positive correlation with luminescence inhibition rate. Protecting the quality of lake watersheds by preventing and reducing their contamination is an effective approach to ensure the sustainability of the drinking water supply. In this study, acute toxicity assessment was conducted on the basis of acute bioluminescence inhibition assay using the marine bacterium Vibrio fischeri as the test organism and Luoma Lake drinking water source in East China as the research target. The suitable ranges of environmental factors, including pH value, organic matter, turbidity, hardness, and dissolved oxygen of water samples were evaluated for the toxicity testing of bioluminescent bacteria. The physicochemical characteristics of water samples at the selected 43 sites of Luoma Lake watershed were measured. Results showed that the variations in pH value (7.31–8.41), hardness (5–20 °d) and dissolved oxygen (4.44–11.03 mg/L) of Luoma Lake and its main inflow and outflow rivers had negligible impacts on the acute toxicity testing of V. fischeri. The luminescence inhibition rates ranged from -11.21% to 10.80% at the 43 sites. Pearson’s correlation analysis in the experiment revealed that temperature, pH value, hardness, and turbidity had no correlation with luminescence inhibition rate, whereas dissolved oxygen showed a weak statistically positive correlation with a Pearson correlation coefficient of 0.455 (p<0.05).     

Effect of high concentrations of inorganic seed aerosols on secondary organic aerosol formation in the m-xylene/NOx photooxidation system

High concentrations (>15 μm³ cm^?3) of CaSO₄, Ca(NO₃)₂ and (NH₄)₂SO₄ were selected as surrogates of dry neutral, aqueous neutral and dry acidic inorganic seed aerosols, respectively, to study the effects of inorganic seeds on secondary organic aerosol (SOA) formation in irradiated m-xylene/NO_x photooxidation systems. The results indicate that neither ozone formation nor SOA formation is significantly affected by the presence of neutral aerosols (both dry CaSO₄ and aqueous Ca(NO₃)₂), even at elevated concentrations. The presence of high concentrations of (NH₄)₂SO₄ aerosols (dry acidic) has no obvious effect on ozone formation, but it does enhance SOA generation and increase SOA yields. In addition, the effect of dry (NH₄)₂SO₄ on SOA yield is found to be positively correlated with the (NH₄)₂SO₄ surface concentration, and the effect is pronounced only when the surface concentration reaches a threshold value. Further, it is proposed that the SOA generation enhancement is achieved by particle-phase heterogeneous reactions induced and catalyzed by the acidity of dry (NH₄)₂SO₄ seed aerosols.