Application research of enhanced in-situ micro-ecological remediation of petroleum contaminated soil

Experimental study of enhanced in-situ micro-ecological remediation of petroleum contaminated loess soil was carried out in Zhongyuan oil production areas, and the enhanced in-situ micro-ecological remediation technique includes optimistic in-situ microbial communities, physical chemistry methods, alfalfa planting and regulation of soil environmental elements. Experiments showed that the oil content in the contaminated soil with oil content about 2 898.25 mg/kg can be reduced about 98.61% after in-situ micro-ecological remediation for 99 days, which demonstrated the effectiveness of in-situ micro-ecological remediation methods for petroleum contaminated soil in central plains of China, and explored the practical and feasible application of these methods.

Monitoring Re-Suspension and Transport of Dioxin Contaminated Sediment to Evaluate the Recovery of a Shallow Urban Creek Post Sediment Remediation

Pringle Creek, identified as the source of dioxin/furan (PCDD/F) contamination to a Lake Ontario harbour was remediated in 2008. Surface sediment collected in 2013 near the floodplain remediation was no longer contaminated (∑17PCDD\Fs < 60 pg/g dw), but residual contamination extended downstream to the creek mouth (surface sediment maximum: ∑17PCDD\Fs 2900 pg/g dw). Nevertheless, sediment ∑17PCDD/F concentrations were lower in 2013 than pre-remediation suggesting that cleaner sediment was being deposited in the creek. Core data confirmed the decrease in sediment contamination through time since the most contaminated sediment was buried. Prior to the development of a remediation strategy for the harbour, the transport of bed-load and suspended sediment contaminated with PCDD/F was assessed. The challenge was the shallow water depth (0.6 m) throughout the creek thereby requiring non-standard sediment traps designed for this study. Suspended sediment collected in traps in 2014 showed residual contamination at the remediated site (∑17PCDD\Fs: 380 pg/g dw;TEQ (TEF fish) < 0.6 pg/g), with concentrations increasing with distance downstream mirroring surface sediment: mean ∑17PCDD\Fs concentration for suspended sediment at the creek mouth was 2200 pg/g (SD 260 pg/g dw) indicating PCDD/F contributions to the harbour. However, congener patterns in bottom sediment and suspended sediment near the remediated site and extending about 100 m downstream were similar to background upstream patterns consistent with atmospheric deposition as the source rather than the historical source which indicated that floodplain remedial actions were successful.

In-situ stabilisation followed by ex-situ composting for treatment and disposal of heavy metals polluted sediments

An innovative in-situ stabilisation treatment followed by ex-situ sediment composting was tested for its ability to treat and dispose of heavy-metal-polluted sediments in a river near the Chinese Pearl Delta. First, polluted sediments were treated in-situ to stabilise the heavy metals. Then the treated sediments were dredged, dewatered and sent for high temperature aerobic composting （HTAC） treatment. Finally, the compost products were used as a fertiliser for fiver bank plants. The stabilisation efficiency of heavy metals during the process was investigated and the results are as follows： （1） using in-situ stabilisation, the extraction concentrations of Cu, Zn and Pb were reduced by 65.0%, 82.2% and 90.0%, respectively, which are much lower than the national standard given in the Identification Standard for Hazardous Waste （GB5085.3-1996）; （2） chemical fraction analysis showed that heavy metals were further stabilized during the HTAC treatment; （3） the concentrations of Cu, Zn and Pb in rainwater leachate through the river bank met the level of class V in the Environmental Quality Standards for Surface Water in China （GB3838-2002）. Therefore, using this new process, the toxicities of heavy metals in sediments were reduced markedly.

Development of in-situ Marine Sediment Geo-Acoustic Measurement System with Real-Time and Multi Frequencies (the Second Generation)

Compared with the laboratory acoustic measurement of sediment samples, the in-situ acoustic measurement in marine sediment is considered more accurate and rehable, because it covers all of the surrounding environment factors and avoids the disturbance during the course of sampling and transporting of sediment samples. A new multi-frequency in-situ geoacoustic measurement system （MFIS^AMS） has been developed. The system can provide acoustic vdocity （compressional wave） and attenuation profiles of the uppermost 4 - 8 m sediment in the seafloor. It consists of 8 channels with 12 frequencies （multi-frequencies） and 0.5 - 2 MHz sampling rates. The data collected can be transmiuted in real-time. Associated with inclinometer and altimeter, it can provide the data for depth emendation. Acoustic velocity and attenuation data have been obtained from two in-situ experiments conducted in the Hangzhou Bay.

Effect of Different Remediators on the Control of Phosphorus Release from Landscape River Sediments

In this paper,different chemicals were added to sediments to control phosphorus release from river sediments by means of different dosing methods,thus reducing the concentration of organic pollutants in overlying water.Two remediators,aluminum sulfate and ferric chloride,were respectively added to six groups of experimental samples in three different covering methods,namely injection,mixing and tiling,and a control group was set up.The results showed that at the initially stationary phase of the experiment,the control effect of phosphorus release from sediments of mixing of aluminum sulfate was the most obvious,followed by tiling and injection into the mud;at the finally stationary phase of the experiment,the control effect of phosphorus release from sediments of injection of aluminum sulfate was the most obvious,followed by mixing and tiling.Under the same coverage,the inhibition effect of aluminum sulfate was more obvious than that of ferric chloride.This paper undertook research into the control effect of phosphorus release from sediments to provide a reference point for the control of water eutrophication in the days to come.

Advances in Microbial Fuel Cells in the Field of Environmental Remediation

In order to protect ecological environment,it is urgent to restore the polluted environment. Among traditional methods of environmental remediation,it is common to add excessive electron donors or electron acceptors to the polluted environment,but these methods have a high cost and can cause secondary pollution easily. Microbial fuel cells( MFCs) can realize the transformation of pollutants and collection of electric energy by using microorganisms as a catalyst; they are clean,efficient and controlled easily and have a wide range of application,so MFCs have wide application prospects in the field of environmental remediation. In this study,MFCs and their applications in the field of environmental remediation were summarized.

Experimental investigation on the effective thermal conductivities of different hydrate-bearing sediments

The natural gas hydrate has been regarded as an important future green energy.Significant progress on the hydrate exploitation has been made,but some challenges are still remaining.In order to enhance the hydrate exploitation efficiency,a significant understanding of the effective thermal conductivity(ETC)of the hydrate-bearing sediment has become essential,since it directly controls the heat and mass transfer behaviors,and thereby determines the stability of hydrate reservoir and production rate.In this study,the effective thermal conductivities of various hydrate-bearing sediments were in-situ measured and studied.The impacts of temperature,particle size and type of sediment were investigated.The effective thermal conductivities of the quartz sand sediments before and after hydrate formation were in-situ measured.The results show the weak negative correlation of effective thermal conductivity of the quartz sand sediment on the temperature before and after the hydrate formation.The effective thermal conductivity of the hydrate-bearing sediment decreases with the increase of particle size of the sediment.The dominant effect of the type of porous medium on the characteristics of the effective thermal conductivity of hydrate-bearing sediment was highlighted.The results indicate that both the effective thermal conductivities of hydrate-bearing quartz sand sediment and hydrate-bearing silicon carbide sediment are weakly negatively correlated with temperature,but the effective thermal conductivity of hydrate-bearing clay sediment is weakly positively dependent on the temperature.In addition,the values of the effective thermal conductivities of various hydrate-bearing sediments are in the order of hydrate-bearing silicon carbide sediment>hydrate-bearing quartz sand sediment>hydrate-bearing clay sediment.These findings could suggest that the intrinsic thermal conductivity of porous medium could control the characteristics of effective thermal conductivity of hydrate-bearing sediment.

黑臭水体底泥处理技术发展现状

我国河湖黑臭水体问题极大地影响了生态环境系统,并对人体健康和经济发展构成威胁。目前随着我国大力推进黑臭水体治理,截污系统逐渐完善,底泥中污染物释放及在厌氧环境下发酵产生的嗅味物质引发的内源污染成为了河湖黑臭的重要原因。因此,黑臭水体底泥治理成为了水环境治理领域的热点和难点,目前针对黑臭水体底泥的主要处理方法有异位修复和原位修复两大类。本文针对黑臭水体底泥的成因、组成及危害做出分析,系统阐述了异位修复技术和原位修复技术的分类、原理及各处理技术的利弊,并对底泥修复技术的发展做出展望,明确了原位修复技术的巨大发展空间。

高岭土改性丝瓜络生物炭修复PAHs污染沉积物及微生物响应

采用高岭土改性生物炭或者使用三维立体,如丝瓜络生物炭(LSBC)修复PAHs污染沉积物,制备了三维立体LSBC(3D-LSBC)、改性三维立体LSBC(3D-K-LSBC)、颗粒LSBC(G-LSBC)和改性颗粒LSBC(G-K-LSBC)四种材料.结果表明:G-K-LSBC修复PAHs污染沉积物效果显著,沉积物PAHs去除率达21.76%,PAHs的修复效率提高了1个数量级.各组下层沉积物PAHs生物有效性明显高于上层沉积物(P<0.05);添加G-LSBC和G-K-LSBC有效降低了沉积物PAHs生物有效性,分别为对照组的43.99%~78.48%和39.08%~72.01%.经过150d修复,沉积物PAHs含量未出现明显垂向分布特征(P>0.05).然而,沉积物微生物群落组成发生了明显变化(P<0.05).在3D-K-LSBC和G-LSBC作用下,沉积物微生物物种丰富度和多样性明显提高;其中,在G-K-LSBC作用下,沉积物群落中具有芳香烃降解和芳香化合物降解功能菌属呈显著富集.G-K-LSBC表现出更高的PAHs污染沉积物修复潜力.此外,高岭土改性显著提高了LSBC材料的稳定性.

不同载体固定活性污泥原位修复轻度淤积底泥的效能

底泥修复是黑臭水体治理中的重要环节,原位修复操作简便且对河道的破坏小。利用固定化菌剂原位修复实验装置,探究了活性炭、沸石、陶粒3种载体固定活性污泥修复轻度淤积底泥的效能。载体物理特性及载体对微生物的吸附特性实验结果表明,活性炭相对于沸石和陶粒具有更丰富的孔隙结构和更强的活性污泥吸附能力,沸石的吸附能力强于陶粒。不同载体固定活性污泥原位修复轻度淤积底泥实验结果表明,3种载体固定活性污泥均能有效降低底泥中有机质含量,其中活性炭固定活性污泥对底泥中有机质的降解效果最佳,60 d内有机质含量可降低45.2%;3种载体固定活性污泥均能促进底泥中重金属离子转移,其中沸石固定活性污泥对重金属离子的去除效果最佳,60 d内对铜离子、铬离子、铅离子的去除率分别达到了28.8%、27.2%、37.2%;此外,3种载体固定活性污泥均能有效去除上覆水中的CODCr、NH3-N、TN、TP,60 d内CODCr去除率基本超过50%,NH3-N、TN、TP去除率基本超过80%。综合底泥和上覆水处理效果可知,活性炭固定活性污泥的表现最优,其次为沸石固定活性污泥。

基于低水位运行的城市河流污染底泥中微生物群落特征及影响因素

针对低水位运行修复城市河流污染底泥微生物机制不清的问题,基于高、低水位下不同城市河流的底泥理化性质检测分析、宏基因组高通量测序及生物信息学分析等手段,开展了低水位运行的城市河流污染底泥中微生物群落特征及影响因素研究。结果表明:变形菌门、放线菌门、厚壁菌门和广古菌门分别是不同水位运行条件下相对丰度最高的细菌门类和古菌门类;高水位运行条件下底泥中细菌的香农指数显著高于低水位运行条件下的指数值(p<0.001),古菌则相反,说明古菌群落可能主导了低水位运行过程中底泥污染物降解过程;低水位运行时变形菌门可能是参与底泥中含氮污染物降解以及氮循环过程的主要微生物门类,α-变形菌纲则可能对底泥中氨氮的去除发挥了重要作用;TOC,TN和NH_(3)-N是影响城市河流底泥中微生物群落变化的主要环境驱动因子;低水位运行不仅能够有效降低底泥中常规污染指标的污染程度,解决底泥内源污染问题,还能显著降低底泥中致病菌的潜在危害,构建更为安全的亲水城市河流生态系统。

液态硝酸钙原位修复黑臭底泥的研究现状及展望

液态硝酸钙被广泛用于黑臭底泥的原位修复,其中硝酸盐作为电子受体优先于Fe(Ⅲ)和硫酸盐被微生物利用,其主要参与以反硝化作用为主导且兼有厌氧氨氧化(Anammox)和硝酸盐异化成铵(DNRA)反应的氮循环过程,驱动生物氧化过程去除底泥中AVS、亚铁及有机物等致黑臭物质。硝酸盐会抑制SO_(4)^(2-)和Fe(Ⅲ)作为电子受体产生S^(2-)和Fe(Ⅱ)的生物还原过程,从而在源头上抑制底泥返黑返臭。然而,底泥中直接注入液态硝酸钙,会使局部硝酸盐浓度过高而抑制功能微生物活性,硝酸盐快速释放至上覆水而导致其利用率低和二次污染风险,调控硝酸钙的释放速率有望解决该问题。

The controlling factors of high suspended sediment concentration in the intertidal flat off the Huanghe River Estuary

The Huanghe River(Yellow River)is known by its high suspended sediment concentration(SSC)in its river mouth tidal flat.However,the factors controlling the high SSC over there are not well understood.Therefore,we conducted 7-d hydrodynamic observations(water depth,wave height,and current velocity)and SSC measurements on the tidal flat off the Huanghe River Mouth.The data shows that in most of time,under the calm sea condition,the SSC ranges 0.1–3.5 g/L,and sediment discharge from the river is the main source.However,when hydrodynamics are enhanced in a tidal cycle and large-scale erosion occurs on the seafloor,resuspended sediment becomes the main source,and the SSC in the water column reaches 17.3 g/L.We find the suspended sediment flux is mainly controlled by the tidal current and Stokes drift,while the wave-induced shear stress could also affect the variation of suspended sediment flux.During the observation period,when sea under calm-rippled conditions,the current-induced resuspended sediment concentration(RSC)was greater than the wave-induced RSC.In contrast,in smooth-wavelet sea conditions,the wave-induced RSC was greater than the current-induced RSC,for instance,a single wave event was found to cause 11.8 cm seabed erosion within 6 h.This study reveals different controlling factors for the high SSC near a river-influenced tidal flat,and helps us get a better understanding of a delta's depositional and erosional mechanisms.

底泥洗脱技术对潟湖水体的修复效果

潟湖是海滨地区由于地形形成的咸淡水交界的半封闭水体,具有特殊的生态价值。万平口潟湖因历史原因与发展需要,亟需改善水体富营养化和底泥厌氧环境。在水环境修复工程中,运用底泥洗脱技术对潟湖水体和底泥进行原位修复。经过洗脱修复后,潟湖水体溶解氧(DO)提高27%、透明度提高191.6%、总氮(TN)降低18.7%。底泥含水率降低44.2%,底泥氧化还原电位(ORP)提高36%。底泥洗脱工程通过修复水质、抑制底泥污染的释放,使潟湖水体富营养化程度得以降低。底泥的团粒结构趋于紧实不易上浮,泥—水界面更加分明,底泥的厌氧环境得以改善,底泥洗脱后,发生水体黑臭问题的风险大大降低,有效控制了内源污染。

水生植物-沉积物微生物燃料电池修复黑臭水

水生植物-沉积物微生物燃料电池(aquatic plant sediment microbial fuel cell,AP-SMFC)是解决当前环境问题及能源短缺的最有发展前景的技术之一。以黑臭水体底泥为底质,构建了芦苇-沉积物微生物燃料电池(标记为APSM1)、美人蕉-沉积物微生物燃料电池(标记为APSM2)和无植物的沉积物微生物燃料电池(标记为SM)共3个实验系统,研究了3个系统沉积物微生物燃料电池的产电特性及对上覆水和底泥的修复效果。结果表明:APSM1,APSM2和SM启动期为8 d;3个实验系统启动结束后均能维持较稳定的产电,输出电压、电流密度和功率密度顺序为APSM1>APSM2>SM。APSM1和APSM2对上覆水化学需氧量(chemical oxygen demand,COD)、氨氮(ammonia nitrogen,NH+4-N)、总磷(total phosphorus,TP)的平均去除率分别为84.3%和81.6%,82.7%和79.3%,85.5%和83.4%,并且显著高于SM。APSM1,APSM2和SM对底泥中的有机质、NH+4-N和总氮(total nitrogen,TN)去除率分别高于80.5%,49.4%和49.2%,3个实验系统间没有显著差异。APSM1和APSM2对底泥中TP的平均去除率分别为72.6%和66.4%,显著高于SM(42.6%)。APSM1,APSM2和SM对底泥中As,Pb的去除率均高于79%,各系统之间没有显著差异;对底泥中Zn,Cr和Cu的去除率均高于80%,显著高于SM(<61%)。芦苇和美人蕉的引入提升了沉积物微生物燃料电池系统的产电性能,增强了系统对上覆水中COD,NH+4-N,TP及底泥中TP,Zn,Cr和Cu的去除效果。

基于“先泥后水”模式的重污染河道底泥碳氮硫同步去除技术研究

针对传统“水驱动泥”修复技术易返黑返臭的弊端,创新性地提出了“先泥后水”的治理模式,即基于“缓释型功能材料协同微生物反硝化强化驱动底泥耗氧物质消除”的思路,研发了底泥碳氮硫污染物同步去除技术,并进行了示范应用。结果表明:原位修复60 d后,底泥中碳氮硫污染物的去除率分别达到36%~41%、45%~58%和89%~91%,氧化层深度达到15.5~17.6 cm。新模式和新技术能有效氧化深层底泥,实现“活泥”带动“活水”,保障了河流水环境健康。

小麦秸秆生物炭添加对养殖池塘底泥重金属的原位修复

养殖底泥作为池塘环境的载体之一,其污染情况直接影响水产品的质量。为保证水产品质量和人体健康,本研究用小麦秸秆生物炭作为修复剂原位添加到受重金属污染的底泥中,辅以薄膜梯度扩散装置(DGT),评估小麦秸秆生物炭添加后在水产品养殖的各个时期,生物体内重金属累积浓度、危险系数、生物有效性和沉积物-水界面扩散通量的变化。结果表明,小麦秸秆生物炭的添加使水产品体内累积的重金属下降15%~55%,4种重金属累积浓度总体下降率顺序为Cd>Pb>Cr>Cu,底栖生物的下降率均高于鱼类,Pb和Cd在生物幼苗期达到39%的最大下降率,Cu和Cr的下降率最大值发生在生长期,其下降率分别为40%和24%。重金属目标危险系数(THQ)下降率范围在15%~55%,与重金属浓度累积下降率相近。在小麦秸秆生物炭原位修复期间,孔隙水中4种重金属有效态浓度在幼苗期下降最快。修复完成时,Cu、Pb、Cd、Cr 4种重金属有效态浓度分别下降了21%、48%、71%、19%。对修复期间沉积物-水界面处各重金属表观扩散通量进行计算的结果表明,底泥中小麦秸秆生物炭的添加加强了底泥作为汇的功能,有助于水体中的重金属向养殖底泥中沉积并且有利于降低水生生物体内的重金属含量。

Research progress and mechanism of nanomaterials-mediated in-situ remediation of cadmium-contaminated soil:A critical review

Cadmium contamination of soil is a global issue and in-situ remediation technology as a promising mitigation strategy has attracted more and more attention.Many nanomaterials have been applied for the in-situ remediation of cadmium-contaminated soil due to their excellent properties of the nano-scale size effect.In this work,recent research progress of various nanomaterials,including carbon nanomaterials,metal-based nanomaterials and nano mineral materials,in the removal of cadmium and in-situ remediation of cadmiumcontaminated soil were systematically discussed.Additional emphases were particularly laid on both laboratory and field restoration effects.Moreover,the factors which can affect the stability of cadmium,main interaction mechanisms between nanomaterials and cadmium in the soil,and potential future research direction were also provided.Therefore,it is believed that this work will ultimately contribute to the myriad of environmental cleanup advances,and further improve human health and sustainable development.