低浓度溶解氧下猪粪固体有机物水解产酸研究

本文以猪粪为发酵原料,通过批式实验研究不同溶解氧(DO)浓度(0—0.26 mg.L-1)、发酵时间(3—12 d)和挥发性固体(VS)浓度(11.14—111.35 g.L-1)对猪粪固体水解酸化过程的影响,确定了低DO浓度下固体有机物优化水解产酸工艺条件:中温35℃,初始VS浓度37.11 g.L-1,初期的DO浓度0.1—0.26 mg.L-1.在此条件下,发酵时间3 d,DO浓度下降到0.10 mg.L-1以下.猪粪发酵液pH值由7.45±0.10降低到5.86±0.17,VS降解率(25.67±1.20)%,挥发性脂肪酸(VFA)中乙酸(3895±91)mg.L-1、丙酸(2313±82)mg.L-1、正丁酸(1361±17)mg.L-1、正戊酸(540±11)mg.L-1.优化条件下的猪粪水解酸化液进行厌氧产甲烷发酵,发酵10 d内产气停止,低溶解氧水解酸化和厌氧产甲烷发酵累计时间仅为13 d,甲烷体积分数(69.5±0.2)%,VS产气率为(0.282±0.011)L CH.4g-1VS.研究结果表明,适当延长发酵时间能够增加VFA中乙酸的含量,初始VS浓度差异对发酵液VFA浓度和VS降解率的影响较显著,低溶解氧能够促进猪粪固体有机物水解过程.     

应用过硫酸盐氧化法预测焦化厂土壤中PAHs的生物有效性

采用过硫酸盐氧化法测定了北京市某焦化厂表层土壤中16种PAHs的生物有效性,并分析了过硫酸盐氧化前、后SOM(土壤有机质)的质量分数及其结构组成,以研究过硫酸盐氧化法预测焦化厂土壤中PAHs生物有效性方面的可行性. 结果表明:①7个供试土壤样品中w(∑PAHs)(16种PAHs质量分数之和)为10.80~249.00 mg/kg,并以HPAHs(高分子量PAHs)为主,不同环数PAHs的质量分数与w(SOM)均呈正相关,二者关系符合对数方程(R2为0.653~0.798). ②依据过硫酸盐氧化前、后土壤中w(PAHs)的变化得到PAHs的生物有效性,其中,2~3环PAHs的生物有效性平均值为0.46,略高于4环PAHs(0.22)和5~6环PAHs(0.28),较高w(SOM)及HPAHs均易引起焦化厂土壤中PAHs生物有效性的下降. ③过硫酸盐氧化前不同环数PAHs的质量分数与氧化后PAHs的残留量呈显著正相关(R2为0.991~0.994),故可利用过硫酸盐氧化前的w(PAHs)预测土壤中PAHs的生物有效性. ④与过硫酸盐氧化前相比,氧化后土壤中w(SOM)平均下降23.0%,FTIR(傅里叶变换红外光谱)分析结果显示,1 448 cm-1处吸收峰表征的脂肪碳可能是被氧化去除的软质碳的主要组分,氧化后SOM中的芳香碳相对吸光度增幅为0.88%~11.62%,可引起SOM的缩合程度加剧、憎水性增强. 因此,过硫酸盐氧化法能够作为测定焦化厂土壤中PAHs生物有效性的快速方法,可利用过硫酸盐氧化前的w(PAHs)预测土壤中PAHs的生物有效性.      

12Cr1MoVG蒸汽管道蠕变的反射式非线性超声无损检测分析

针对传统(收-发分置)透射式非线性超声检测方法在现场应用受到众多制约的问题,提出二次谐波(收-发合置)的反射式非线性超声检测思路,通过采集并分离超声检测信号一次底波的反射信号获取非线性超声检测中基波和二次谐波信号,并设计搭建反射式非线性超声实验系统,进行2万小时12Cr1MoVG钢高温蒸汽管道检测实验并与测试样品的里氏硬度值进行比对。研究结果表明：该管道测点的非线性参量β在0.005～0.03变化与其硬度值变化(420～440 HL)呈负相关,即随着试样性能下降β值增大,而硬度值下降。研究结果可为在役高温蒸汽管道蠕变程度的检测提供参考。     

The use of spatial autocorrelation analysis to identify PAHs pollution hotspots at an industrially contaminated site

The identification of contamination “hotspots” are an important indicator of the degree of contamination in localized areas, which can contribute towards the re-sampling and remedial strategies used in the seriously contaminated areas. Accordingly, 114 surface samples, collected from an industrially contaminated site in northern China, were assessed for 16 polycyclic aromatic hydrocarbons (PAHs) and were analyzed using multivariate statistical and spatial autocorrelation techniques. The results showed that the PCA leads to a reduction in the initial dimension of the dataset to two components, dominated by Chr, Bbf&Bkf, Inp, Daa, Bgp, and Nap were good representations of the 16 original PAHs; Global Moran’s I statistics indicated that the significant autocorrelations were detected and the autocorrelation distances of six indicator PAHs were 750, 850, 1,200, 850, 750, and 1,200 m, respectively; there were visible high–high values (hotspots) clustered in the mid-bottom part of the site through the Local Moran’s I index analysis. Hotspot identification and spatial distribution results can play a key role in contaminated site investigation and management.     

土壤水研究进展与方向评述

土壤水与大气水、地表水、地下水和植被有着紧密的联系,是水资源中最重要和最复杂的部分.为了给农业生产、生态恢复、环境治理以及水资源合理利用提供有效的理论指导,国内外已经有了较多关于土壤水的研究成果.在综述土壤水研究的进展和已有成果基础上,重点分析了当前在土壤水研究方向上所存在的问题.以往的土壤水研究较多集中于其物理性质,如水分含量及利用、土壤水盐分及其运移规律、土壤水动力学及数学模拟模型研究、土壤水水量计算及水平衡研究等,而对其化学性质的研究和认识较为不足,特别是其地球化学特征的研究更是较少.然而土壤水的地球化学特征同样是决定着土壤水的运移规律的重要因素,但目前此方向的研究只有土壤水同位素地球化学研究.由于土壤水取样困难,土壤水元素地球化学和与环境污染有关的土壤水地球化学研究也仍然较少.因此,今后应当加强对土壤水地球化学特征的研究,并逐步提高实验技术和积累研究经验,以期能更全面地揭示土壤水的本质特征及其运移规律.     

焦化污染土壤有机质不同组分中多环芳烃分布及其生物有效性分析

土壤有机质（SOM）是影响土壤中多环芳烃（PAHs）赋存的重要因素,本文对3个地区的PAHs污染土壤,将其分为土壤轻组分（LF）、重组分（HF）以及另外3个有机质组分（松散结合的腐殖质（H₁）、稳定结合的腐殖质（H₂）和紧密结合的腐殖质（H₃））,采用过硫酸盐氧化法间接测定土壤中16种PAHs的生物有效性,分析了氧化前、后土壤分离的各组分之间PAHs的浓度以及其结构组成.结果表明：①LF中PAHs浓度为226.51~11240.40 mg·kg^-1,HF则为29.81~1506.00 mg·kg^-1,虽然LF占总样品的质量百分比仅为1.41%~2.43%,所含的PAHs占土壤中PAHs总量的13%~17%,LF富集PAHs的能力要远大于HF;②原土中2~3环的PAHs生物有效性为0.48~0.81,均值为0.68,略高于∑PAHs均值（0.67）、4环（0.55）以及5~6环（0.30）;而HF中4环PAHs生物有效性为0.58~0.68,均值为0.61,略高于∑PAHs均值（0.56）、5~6环（0.45）以及2~3环（0.60）,原土中PAHs生物有效性均值要比HF高,低环PAHs生物有效性要高于高环.③对比HF和LF,FTIR（傅里叶变换红外光谱）分析结果显示,LF比HF在波长为1033 cm^-1处相对吸光度明显增加,增幅为11.41%~22.62%,而在3500~3300 cm^-1处LF比HF相对吸光度则略有下降,降幅为1.57%~16.36%,因而LF中含C—O官能团的物质较多,表明LF比HF含有更多的碳水化合物以及高度聚合物等,导致LF中所含的PAHs要远高于其他组分,而HF中的PAHs多分布于H₃中,可能是由于H₃中存在较高的疏水性有机质.在对PAHs污染土壤修复治理以及健康风险评估中,应重视土壤LF组分及其所含PAHs生物有效性规律以及PAHs污染严重时HF中PAHs可能存在较多的情况,土壤中有机物成分显著影响土壤中PAHs的分布和生物利用度这一事实可用于PAHs污染的土壤.     

普光集输站场安全放空系统技术研究

通过对普光集输站安全放空系统的火炬系统、放空系统和安全阀的设计,探讨站内放空管、火炬总管的合理布局并安装,经实际应用,将压力控制在0.1MPa以内,火炬总管流速小于0.5马赫,能满足系统安全使用的要求。     

Forward osmosis coupled with lime-soda ash softening for volume minimization of reverse osmosis concentrate and CaCO3 recovery: A case study on the coal chemical industry

• Forward osmosis (FO) coupled with chemical softening for CCI ROC minimization • Effective removal of scale precursor ions by lime-soda ash softening • Enhanced water recovery from 54% to 86% by mitigation of FO membrane scaling • High-purity CaCO₃ was recovered from the softening sludge • Membrane cleaning efficiency of 88.5% was obtained by EDTA for softened ROC Reverse osmosis (RO) is frequently used for water reclamation from treated wastewater or desalination plants. The RO concentrate (ROC) produced from the coal chemical industry (CCI) generally contains refractory organic pollutants and extremely high-concentration inorganic salts with a dissolved solids content of more than 20 g/L contributed by inorganic ions, such as Na⁺, Ca²⁺, Mg²⁺, Cl⁻, and SO₄²⁻. To address this issue, in this study, we focused on coupling forward osmosis (FO) with chemical softening (FO-CS) for the volume minimization of CCI ROC and the recovery of valuable resources in the form of CaCO₃. In the case of the real raw CCI ROC, softening treatment by lime-soda ash was shown to effectively remove Ca²⁺/Ba²⁺ (>98.5%) and Mg²⁺/Sr²⁺/Si (>80%), as well as significantly mitigate membrane scaling during FO. The softened ROC and raw ROC corresponded to a maximum water recovery of 86% and 54%, respectively. During cyclic FO tests (4 × 10 h), a 27% decline in the water flux was observed for raw ROC, whereas only 4% was observed for softened ROC. The cleaning efficiency using EDTA was also found to be considerably higher for softened ROC (88.5%) than that for raw ROC (49.0%). In addition, CaCO₃ (92.2% purity) was recovered from the softening sludge with an average yield of 5.6 kg/m³ treated ROC. This study provides a proof-of-concept demonstration of the FO-CS coupling process for ROC volume minimization and valuable resources recovery, which makes the treatment of CCI ROC more efficient and more economical.     

多形态多水平氮添加对温带森林土壤根系呼吸和微生物呼吸的影响

为阐明不同水平、不同形态的氮添加对土壤总呼吸、土壤微生物呼吸、根系呼吸的影响及微生物机制,本研究以温带森林土壤为研究对象,开展多形态(硝态氮(NaNO_3)、铵态氮((NH_4)_2SO_4)和混合态氮(NH_4NO_3))多水平(50 kg N·ha~(-1)·a~(-1)和150 kg N·ha~(-1)·a~(-1))的增氮控制实验.在施氮后的第7—9年,利用静态箱-气相色谱法研究土壤呼吸组分和磷脂脂肪酸方法研究微生物群落丰度和群落结构的改变.结果表明,氮添加显著提高了土壤硝态氮和铵态氮含量,而土壤pH平均降低0.85个单位.在施氮后的第7—9年,氮添加将会减弱土壤呼吸活动,高水平的氮添加效应强于低水平氮添加;就形态来说,(NH_4)_2SO_4起到促进效应,而NH_4NO_3则逐渐由促进效应转变成抑制效应,例如在2019年(施肥后第9年),高水平的(NH_4)_2SO_4施加分别提高土壤总呼吸和微生物呼吸的34.06%和37.95%,而高水平NH_4NO_3添加则分别抑制了土壤总呼吸和微生物呼吸的27.62%和31.70%.而高水平的(NH_4)_2SO_4添加对根系呼吸有促进作用,而高水平的NH_4NO_3则有抑制效应.微生物呼吸和细菌、真菌显著正相关,和真菌/细菌比值也呈正相关.总之,土壤呼吸各组分对氮添加的响应受氮素形态和水平的控制,特定森林土壤碳排放量对土壤氮基质响应具有多阶段性,微生物呼吸的降低反映了土壤有机质分解速度的降低,这有可能会进而促进土壤碳的积累,达到氮促碳汇的效果.     

Combined bioremediation of atrazine-contaminated soil by <Emphasis Type="Italic">Pennisetum</Emphasis> and <Emphasis Type="Italic">Arthrobacter</Emphasis> sp. strain DNS10

Strain DNS10 was isolated from the black soil collected from the northeast of China which had been cultivated with atrazine as the sole nitrogen source. Pennisetum is a common plant in Heilongjiang Province of China. The main objective of this paper was to evaluate the efficiency of plant–microbe joint interactions (Arthrobacter sp. DNS10 + Pennisetum) in atrazine degradation compared with single-strain and single-plant effects. Plant–microbe joint interactions degraded 98.10 % of the atrazine, while single strain and single plant only degraded 87.38 and 66.71 % after a 30-day experimental period, respectively. The results indicated that plant–microbe joint interactions had a better degradation effect. Meanwhile, we found that plant–microbe joint interactions showed a higher microbial diversity. The results of microbial diversity illustrated that the positive effects of cropping could improve soil microbial growth and activity. In addition, we planted atrazine-sensitive plants (soybean) in the soil after repair. The results showed that soybean growth in soil previously treated with the plant–microbe joint interactions treatment was better compared with other treatments after 20 days of growth. This was further proved that the soil is more conducive for crop cultivation. Hence, plant–microbe joint interactions are considered to be a potential tool in the remediation of atrazine-contaminated soil.