丝光印染废碱液回用技术的研究

印染企业丝光机排出的废碱液,Na0H质量浓度为3%～5%,废水温度在50℃～70℃,色度>1000倍,SS>400mg/L,含较多棉纱线等,为探讨废碱液回收技术的合理性及可行性,本中试系统采用"滤网过滤+板框压滤+陶瓷膜过滤+蒸发浓缩"的耦合技术,对丝光机排放的废碱液进行预处理及浓缩,中试结果表明,该技术可达到废碱液100%回用,处理后的碱液浓度可达15%～25%,SS<30mg/L,色度<100倍,达到印染行业丝光工序回用的要求。     

Nutrients regeneration pathway, release potential, transformation pattern and algal utilization strategies jointly drove cyanobacterial growth and their succession

In order to better understand the contribution of nutrients regeneration pathway, release potential and transformation pattern to cyanobacterial growth and succession, 7 sampling sites in Lake Chaohu with different bloom degree were studied every two months from February to November 2018. The carbon, nitrogen (N) and phosphorus (P) forms or fractions in surface, interstitial water and sediments as well as extracellular enzymatic activities, P sorption, specific microbial abundance and community composition in sediments were analyzed. P regeneration pathway was dominated by iron-bound P desorption and phosphorus-solubilizing bacteria solubilization in severe-bloom and slight-bloom area respectively, which both resulted in high soluble reactive phosphorus (SRP) accumulation in interstitial water. However, in severe-bloom area, higher P release potential caused the strong P release and algal growth, compared to slight-bloom area. In spring, P limitation and N selective assimilation of Dolichospermum facilitated nitrate accumulation in surface water, which provided enough N source for the initiation of Microcystis bloom. In summer, the accumulated organic N in Dolichospermum cells during its bloom was re-mineralized as ammonium to replenish N source for the sustainable development of Microcystis bloom. Furthermore, SRP continuous release led to the replacement of Dolichospermum by Microcystis with the advantage of P quick utilization, transport and storage. Taken together, the succession from Dolichospermum to Microcystis was due to both the different forms of N and P in water column mediated by different regeneration and transformation pathways as well as release potential, and algal N and P utilization strategies.     

延安新造贫瘠耕地适生农作物及其高产品种筛选

2013?—?2017年延安市实施了治沟造地工程,总投资约50亿,新造耕地3.33万hm2,但是研究发现新造耕地土壤贫瘠,改良需要较长时间.因此筛选新造耕地适生农作物及其高产品种,指导农业生产实践显得尤为重要和迫切.为此,本研究开展延安新造耕地适生农作物筛选实验,发现马铃薯为新造耕地适生农业作物,进而从甘肃等地选择有代表性的抗性强、产量高的11个马铃薯品种,在延安安塞区高桥镇南沟村开展了最适马铃薯品种筛选的大田实验.结果表明:(1)从产量、产值以及对土壤改良角度综合考虑,马铃薯为延安新造耕地适生作物,其产量和产值均显著高于其他农作物,且马铃薯有利于降低土壤pH值,改善土壤团粒结构,提升有机质与氮磷含量,适宜于新造贫瘠耕地种植.(2)"新大坪"、"青薯168"、"克新1号"产量均显著高于本地马铃薯品种(P<0.01),且出苗率、水分利用效率、净光合效率、气孔导度、蒸腾速率和胞间CO2浓度均高于本地马铃薯品种(P<0.05);"陇薯7号"出苗率、气孔导度、蒸腾速率和胞间CO2浓度也高于本地品种(P<0.05),其水分利用效率低(P>0.05),限制了其光合效率(P>0.05),没有表现出高产效果(P>0.05),但是个头大、表面光滑、卖相好.(3)进一步大田验证实验发现,"新大坪"不但产量高,而且出苗率、株高、净光合速率、气孔导度、淀粉、还原糖、蛋白质均优于本地马铃薯品种;"青薯168"产量也显著高于本地马铃薯品种,其胞间CO2浓度、蒸腾速率、PSⅡ实际光化学效率、最大光化学量子产量、PSⅡ潜在活性均优于本地品种;"陇薯7号"与"克新1号"产量也高于本地品种,但无显著性差异(P>0.05).利用模糊数学隶属函数方法综合评价发现,"新大坪"隶属度值最大,为新造耕地最适宜种植推广的品种,其次为"陇薯7号"与"青薯168",而"克新1号"综合评价劣于本地品种.     

曹妃甸近岸表层沉积物粒度和粘土矿物分布特征研究

为探讨曹妃甸近岸海区表层沉积物粒度和粘土矿物组成和分布特征,利用激光粒度仪和X-射线衍射(XRD)分析的方法对曹妃甸近岸海区15个表层沉积物样品进行分析。结果表明:曹妃甸近岸海区沉积物以粉砂为主(45.2%),其次是砂(30.2%)和粘土(24.6%);研究区内四种粘土矿物含量依次为伊利石(55.8%)蒙皂石(24.9%)绿泥石(9.9%)高岭石(6.7%)。研究表明曹妃甸近岸表层沉积物含量和分布特征受物源、水动力等自然因素和围填海工程等人为因素共同影响;其中,围填海工程的长期实施对研究区表层沉积物中较细颗粒(粉砂和粘土)的分布影响较为明显;伊利石、高岭石和绿泥石分布特征与围填海导致的水动力改变密切相关。研究结果对曹妃甸近岸海区的沉积特征及沉积物物源、了解围填海工程对海洋沉积环境的影响有着一定的科学意义。     

Fate of microplastics in a coastal wastewater treatment plant: Microfibers could partially break through the integrated membrane system

• Fate of microplastics in integrated membrane system for water reuse was investigated. • Integrated membrane system has high removal efficiency (>98%) for microplastics. • Microplastics (>93%) were mainly removed through membrane bioreactor treatment. • Small scale fiber plastics (<200 μm) could break through reverse osmosis (RO) system. • The flux of microplastics maintained at 2.7 × 10¹¹ MPs/d after the RO treatment. Rare information on the fate of microplastics in the integrated membrane system (IMS) system in full-scale wastewater treatment plant was available. The fate of microplastics in IMS in a coastal reclaimed water plant was investigated. The removal rate of microplastics in the IMS system reached 93.2% after membrane bioreactor (MBR) treatment while that further increased to 98.0% after the reverse osmosis (RO) membrane process. The flux of microplastics in MBR effluent was reduced from 1.5 × 10¹³ MPs/d to 10.2 × 10¹¹ MPs/d while that of the RO treatment decreased to 2.7 × 10¹¹ MPs/d. Small scale fiber plastics (<200 μm) could break through RO system according to the size distribution analysis. The application of the IMS system in the reclaimed water plant could prevent most of the microplastics from being discharged in the coastal water. These findings suggested that the IMS system was more efficient than conventional activated sludge system (CAS) for the removal of microplastics, while the discharge of small scale fiber plastics through the IMS system should also not be neglected because small scale fiber plastics (<200 μm) could break through IMS system equipped with the RO system.     

Quantitative analysis of microplastics in coastal tidal-flat reclamation in Dongtai,China

• Reclamation projects are important disturbances on microplastic risk in coasts. • Tidal-flat reclamation area is a large storage medium for sedimentary microplastics. • Aging and distribution features of soil microplastics show spatial heterogeneity. • Coastal weathered engineering geotextiles are a significant threat to marine health. Coastal tidal flats have received considerable attention in recent years, as they provide a direct channel for the discharge of terrestrial microplastics into the ocean. Land reclamation is occurring increasingly frequently in coastal tidal-flats; however, the environmental impacts of these activities remain unclear. Therefore, this pioneering study assessed the microplastic emission characteristics of reclamation geotextiles and performed a risk assessment accordingly. Morphological characterization of geotextile samples collected from five sites in Dongtai, China, provided evidence of sedimentary weathering. Based on several assumptions, the average abundance of microplastics in soil covered by geotextiles was estimated to reach 349±137 particles/kg dry weight, with the total microplastic load in the reclaimed area estimated to be 20.67±8.06 t. Compared with previous studies, this research demonstrates that coastal reclamation areas store a high concentration of microplastics, aggravating marine microplastic pollution. Moreover, conditional fragmentation model results revealed that the weathering and distribution characteristics of soil microplastics in coastal tidal-flat areas exhibit spatial heterogeneity, being more easily affected by natural factors (such as tides) than those in inland areas. As a result of tides, the annual discharge of geotextile-originating microplastics from the studied areas into the ocean was approximately 2465.52±960.77 t. These findings prove that the risks posed by engineering-microplastics are significant, indicating that further investigations are required on the precise laws of transfer and migration, as well as the toxicity mechanisms, in order to improve analytical techniques and policies in this field.     

滨海滩涂围垦区不同围垦年限土壤酶活性变化及其与理化性质关系

土壤酶几乎参与所有的土壤生物化学过程,厘清土壤酶活性与土壤理化性质的关系能够揭示围垦后土壤质量变化状况,为土壤生态系统的科学调控提供理论依据.选择江苏中部如东不同围垦年限(7、32、40、63 a)的滩涂围垦区为研究对象,以未围垦光滩作为对照(0 a),利用经典统计学分析和冗余分析研究不同围垦年限土壤酶活性变化过程,及其与土壤理化性质之间的关系.经典统计学分析表明不同围垦年限间土壤酶活性具有显著性差异,淀粉酶、脱氢酶和酸性磷酸酶活性随着围垦年限的增长呈现出先上升后下降的过程,而脲酶和碱性磷酸酶活性则随着围垦年限的增长呈现出先上升-下降-再上升的过程.同时,不同围垦年限的表层土壤酶活性基本上高于深层.冗余分析表明5种理化性质在前两轴累积能够解释土壤酶活性的69.8%,pH、电导率、土壤有机碳、全氮和全磷与土壤酶活性呈极显著相关关系(P0.01).土壤理化性质对土壤酶活性影响重要性大小排序为全氮有机碳pH全磷电导率.     

东部平原矿区复垦土壤微生物群落特征及其组装过程

复垦对恢复矿区土壤生产力极为重要,但复垦土壤生产力重建的微生物学机制尚不清晰.为此,采集复垦8 a、复垦11 a、复垦14 a和复垦17 a这4个复垦时长和1个未复垦对照共75个表层土样进行16S rRNA扩增子高通量测序,分析微生物群落组成、潜在功能及其组装机制.结果表明：(1)群落丰富度随复垦时间增加而增加,且高于对照样.但群落多样性和均匀度却随复垦时间增加而降低(P<0.05);(2)复垦土壤中酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)、变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)占主导地位,且前两者相对丰度显著高于对照样(P<0.05),后两者则相反(P<0.05);(3)复垦土壤中辅酶转运与代谢、翻译、核糖体结构与生物发生等8种功能呈正向演替,随复垦时长不断增强;(4)平原矿区微生物群落生态网络模块性良好,且关键类群多属酸杆菌门和拟杆菌门.群落组装以确定性过程为主导,同质性选择贡献最大,主要受当地特殊环境操控.这些发现为改善复垦土壤生产力和生态服务提供了理论依据.     

围垦养殖与退塘还湿对闽江河口湿地土壤铁碳结合特征的影响

为探究围垦养殖与退塘还湿对河口湿地土壤铁-碳结合特征的影响,本研究选择福建省闽江河口天然湿地、养殖塘以及退塘还湿样地为研究对象,对3个类型中的土壤铁结合态有机碳（Fe-OC）及其相关指标进行测定与分析.结果显示：①湿地围垦养殖显著影响土壤Fe-OC含量,其含量在退塘还湿后有所回升;②土壤氧化还原过程显著影响土壤中铁相的转化,湿地围垦后土壤中无定形态铁（Fe_o）与络合态铁（Fe_p）含量显著下降（p<0.05）,而退塘还湿后土壤中游离态铁（Fe_d）含量显著下降（p<0.05）;③养殖塘复湿初期,土壤总有机碳（SOC）含量低于养殖塘,且3样地中土壤Fe-OC均主要以吸附途径结合,其在土壤总有机碳中的占比为4.25%~7.85%;④土壤Fe-OC含量与土壤SOC、Fe_p、氧化铁的络合度呈显著正相关（p<0.01）,与土壤Fe_o含量呈显著正相关（p<0.05）,土壤容重和pH是影响土壤Fe-OC含量的重要环境因素.湿地围垦养殖与退塘还湿能够显著影响土壤Fe-OC含量,相比天然湿地,土壤Fe-OC含量在围垦后持续下降,在复湿过程中有所回升.结果表明退塘还湿对增加湿地碳汇功能具有积极意义.