絮凝沉淀磁吸附工艺在富营养化水体治理中的应用

为从根本上解决富营养化湖泊水内源污染问题,从实验室和工程实验2个方面考证了絮凝沉淀磁吸附工艺应用于治理富营养化水内源污染的可行性,从絮凝和化学沉淀角度分析了该工艺的原理.研究结果表明,该工艺能快速、便捷、高效治理湖泊蓝藻水华,且投入的絮凝剂绿色环保、无二次污染,具有广泛的应用前景.     

湖泊底泥中蓝藻越冬和复苏行为研究进展

富营养化湖泊蓝藻水华暴发是重大水环境问题.深入了解越冬期间蓝藻在底泥中的活动过程及其习性,为对此阶段采取有效措施抑制蓝藻复苏提供理论依据,为湖泊蓝藻治理提供新思路.综述了越冬期蓝藻细胞形态、活性、藻毒性、上浮能力等变化以及外部条件如温度,光照强度、DO、营养盐等对其复苏的影响,指出现阶段研究中存在的问题,明确未来的研究...     

湖泊富营养化模型的研究进展

湖泊的富营养化是全球普遍关注的环境问题之一.湖泊的富营养化模型是防治、修复和治理湖泊富营养化的重要决策工具.按研究的侧重点不同,将湖泊富营养化模型分为简单回归模型、水质模型、生态模型和生态-水动力水质模型,并分别回顾了四类模型的研究进展.最后指出湖泊富营养化模型的发展趋势,强调不确定理论、3S技术、耦合模型是今后湖泊富营养化模型研究的重点,应在此基础上建立通用的模拟、预测、评价和优化模型,为湖泊富营养化管理提供科学依据.     

湖泊富营养化模型的研究进展

湖泊的富营养化是全球普遍关注的环境问题之一.湖泊的富营养化模型是防治、修复和治理湖泊富营养化的重要决策工具.按研究的侧重点不同,将湖泊富营养化模型分为简单回归模型、水质模型、生态模型和生态-水动力水质模型,并分别回顾了四类模型的研究进展.最后指出湖泊富营养化模型的发展趋势,强调不确定理论、3S技术、耦合模型是今后湖泊富营养化模型研究的重点,应在此基础上建立通用的模拟、预测、评价和优化模型,为湖泊富营养化管理提供科学依据.     

巢湖蓝藻的机械清除工艺以及藻水分离实验研究简

对巢湖蓝藻进行机械清除以及藻水分离实验研究,实验采用的浮式围栏引导-机械清除-投加剥离液辅助机械清除工艺处理量大,除藻效率高,筛网过滤-浓缩-卧螺离心机脱水成藻泥的藻水分离工艺较为理想,藻泥含水率仅为89%。2011年5—10月在巢湖运用上述方法清除湖面水华蓝藻,共处理富藻水1.6万m³,得到藻泥970 t,累计清除蓝藻106.7 t（干重）。按照所清除蓝藻的总氮、总磷的平均含量计算,相当于从湖中移除了氮6.25 t,磷2.1 t。表明在富营养湖泊中水华蓝藻大量暴发时,采用上述方法除藻,对控制蓝藻水华污染,有效降低内源氮、磷等污染物负荷具有十分重要的作用。     

巢湖蓝藻的机械清除工艺以及藻水分离实验研究

对巢湖蓝藻进行机械清除以及藻水分离实验研究,实验采用的浮式围栏引导一机械清除．投加剥离液辅助机械清除工艺处理量大,除藻效率高,筛网过滤-浓缩-卧螺离心机脱水成藻泥的藻水分离工艺较为理想,藻泥含水率仅为89％。2011年5-10月在巢湖运用上述方法清除湖面水华蓝藻,共处理富藻水1．6万m3,得到藻泥970t,累计清除蓝藻106．7t（干重）。按照所清除蓝藻的总氮、总磷的平均含量计算,相当于从湖中移除了氮6．25t,磷2．1t。表明在富营养湖泊中水华蓝藻大量暴发时,采用上述方法除藻,对控制蓝藻水华污染,有效降低内源氮、磷等污染物负荷具有十分重要的作用。     

改性当地土壤湖泊综合修复技术对浮游植物群落变动的影响

采用改性当地土壤湖泊综合修复技术从2008年夏季到2010年夏季连续在太湖十八湾围隔内实施夏季应急除藻工程和春季底泥调控工程,通过连续监测浮游植物的群落变动发现:在2009年,春季和夏季工程后浮游植物门类虽在短时间内减少,但是一个月内均又恢复,而且春季工程在短时间内可以在一定程度上抑制蓝藻的种类和比例的增加,又可提高硅藻和绿藻的种类和比例,这对于春季沉水植被的恢复和抑制蓝藻的复苏都有积极意义;从长时间周年变化来看,春季和夏季工程在围隔内连续实施2年,蓝藻水华暴发周期和暴发规模均呈逐渐缩短趋势。这对于进一步开展蓝藻复苏和蓝藻水华暴发的机理研究和控制技术的研究都有一定的指导意义。     

微滤膜与活性炭联用工艺去除富营养化水源水中藻类

湖泊及水库含藻水问题带有一定的普遍性,处理技术复杂,难度较大。因此,除藻技术的提高和发展显得越来越紧迫。膜处理技术在给水中的应用是水处理技术的重大突破,正逐渐成为21世纪水处理技术中最有发展前途的技术。本文以继承和吸收成熟技术,并将其工程化,以便及时解决具体问题为原则,根据国内外最新水质标准要求,提出了微滤膜与活性炭联用的除藻新上艺,并对除藻工艺方案确定原则、研究内容和目标,以及除藻工艺方案设计进行了说细分析说明。本文认为微滤膜技术在我国供水行业推广已经具备了较好的条件,在不断积累经验的基础上可以达到大规模工程应用。应用微滤膜与活性炭联用工艺解决富营养化水源水中藻类问题在技术上是成熟的,在经济上是可行的。     

连续式自清洁蓝藻收集设备的中试研究

近年来湖泊富营养化日益加重,各种除藻技术层出不穷,以机械捞藻法、滤网式收集法、排气分离式收集法等为代表的蓝藻收集方法迅速出现。为了进一步提高蓝藻的收集效率,开发了一种新型的连续式自清洁蓝藻收集设备,以叶绿素a含量为主要指标,判断蓝藻去除效果。在进水泵频率30 Hz,进水压力0.11 MPa的条件下,每间隔30 min洗...     

湖水源热泵系统尾水排放对湖泊富营养化进程的影响研究

以重庆市开县人民医院湖水源热泵工程为例,通过对该工程运行期间尾水受纳湖泊水域水温、氮、磷和浮游植物的长期监测,研究了湖水源热泵系统尾水对湖泊富营养化进程的影响。结果表明,夏季系统的长期运行导致了排放口附近水域水温的升高;当系统温排水水温在30℃以下时,温排水造成的温升使得排放口附近氮、磷含量升高,蓝、绿藻数量大幅增加,加速了湖泊的富营养化进程;当温排水水温达到33℃以上时,过高的温度会抑制藻类的生长。冷排水使湖泊排放口近水域浮游植物总量降低,且硅藻占总藻的比例增大,冷排水同时抑制了蓝藻和其他一些藻类的生长,对湖泊富营养化有一定缓解作用。但另一方面,由于温差较小,且冷排水的扰动作用加速了湖泊沉积物中营养盐的释放,因而冷排水对湖泊富营养化进程又有一定促进作用。     

Influence of algal bloom degradation on nutrient release at the sediment–water interface in Lake Taihu, China

Algal bloom could drastically influence the nutrient cycling in lakes. To understand how the internal nutrient release responds to algal bloom decay, water and sediment columns were sampled at 22 sites from four distinct regions of China’s eutrophic Lake Taihu and incubated in the laboratory to examine the influence of massive algal bloom decay on nutrient release from sediment. The column experiment involved three treatments: (1) water and sediment (WS); (2) water and algal bloom (WA); and (3) water, sediment, and algal bloom (WSA). Concentrations of dissolved oxygen (DO), total nitrogen (TN), total phosphorus (TP), ammonium (NH ₄ ⁺ -N), and orthophosphate (PO ₄ ^3? -P) were recorded during incubation. The decay of algal material caused a more rapid decrease in DO than in the algae-free controls and led to significant increases in NH ₄ ⁺ -N and PO ₄ ^3? -P in the water. The presence of algae during the incubation had a regionally variable effect on sediment nutrient profiles. In the absence of decaying algae (treatment WS), sediment nutrient concentrations decreased during the incubation. In the presence of blooms (WSA), sediments from the river mouth released P to the overlying water, while sediments from other regions absorbed surplus P from the water. This experiment showed that large-scale algal decay will dramatically affect nutrient cycling at the sediment–water interface and would potentially transfer the function of sediment as “container” or “supplier” in Taihu, although oxygen exchange with atmosphere in lake water was stronger than in columns. The magnitude of the effect depends on the physical–chemical character of the sediments.     

Effects of hydrological change on the risk of riverine algal blooms: case study in the mid-downstream of the Han River in China

Algal blooms usually occur in semi-closed water bodies such as lakes or estuaries; however, it has occurred frequently in the mid-downstream of the Han River (MSHR) in China since the 1990s. We made a comparative analysis of the hydrological conditions and identified the hydrological condition thresholds that induce algal blooms. From the hydrodynamic point of view, the changes and characteristics of the hydrological conditions in the MSHR were analyzed. Furthermore, the influence on the risk of algal blooms under different design water transfer schemes for the middle route of the South-to-North Water Diversion Project (SNWDP) was studied. The results indicated that (1) the flow in the MSHR less than 900 m³/s and water level in the Yangtze River higher than 14 m provided a suitable hydrological environment for diatoms multiply. (2) The flow of the MSHR showed a downtrend, while the water level of the Yangtze River showed an uptrend. There were variations in hydrological processes. Through specific IHA index analysis, the fact of flow reduction in the MSHR was demonstrated, and further indicated that algal bloom outbreak was in low flow period. (3) The water transfer in the middle route of SNWDP affected the risk probability of algal blooms. The more the amount of water transfer, the greater the risk probability of algal blooms. It was the Water Diversion Project from Yangtze River to Han River (WDPYHR) that replenished flow of the MSHR and was conducive to the prevention and control of algal bloom risk.

     

生物制剂法治理藻类水华

在广州市黄埔区某公园池塘进行现场围隔对比实验,通过投加固定化生物催化剂(IBC)治理藻类水华。结果表明,在IBC中细菌的直接或间接杀藻的作用下,水体中的藻类生物量迅速降低,叶绿素a去除率达到81.5%;微生物的快速生长及酶和酶活因子的协同作用下,水中污染物被快速降解,使水体中的总氮、氨氮和COD的浓度快速下降,去除率分别达到81.9%、80.3%和65.3%,并维持在低水平,进一步抑制了藻类水华的形成和发展,加快水体的净化。     

鲢鱼放养控制北京城市河湖水华试验研究

介绍了利用鲢鱼控制北京城市河湖水华的试验研究,通过不同放养密度(0、17、51和103 g/m3)的现场围隔试验,对鲢鱼放养对水体水质和浮游生物的影响进行了分析.研究结果表明,鲢鱼放养使有鱼围隔中浮游生物量极低,从而使浮游植物基本不受浮游动物影响,而直接受鱼类影响;同时,中等密度(51 g/m3)的鲢鱼放养使水华蓝藻和微小藻的生长均得到了有效抑制,使藻类生物量最低.     

Study on the dynamics of algal bloom and its influence factors in Tolo Harbour, Hong Kong.

In this paper, the semi-enclosed bay named Tolo Harbour and Channel in Hong Kong, which was frequently attacked by red tides, was used as a case study. Data sets related to marine water quality, river nutrients, and meteorological conditions recorded between 1988 and 1999 were chosen for statistical analysis. A multivariate analysis showed that algal growth, represented by the chlorophyll a concentration, had obvious spatial and temporal variations in the study area. The chlorophyll a concentration had a consistently decreasing trend from the inner part of the Harbour and surface waters to the outer part and bottom waters. The temporal variations had a markedly seasonal variation with high bioproductivity in spring and winter. There were long-term fluctuations in the chlorophyll a concentration with a high-low-high pattern in the study period. Nutrients and hydrological and meteorological conditions were important factors of algal bloom. Besides nitrogen, which was the most critical factor of algal bloom for the whole water body, total phosphorus in the surface waters and phosphate (PO4) and silica (SiO2) in the bottom waters also showed strongly positive or negative correlations with the chlorophyll a level. For the meteorological conditions, global solar radiation was the key factor of massive algal bloom in the study period, while rainfall and wind direction were the most important factors of seasonal variation.     

A modified cyanobacteria prediction model based on cellular automata model using N and P concentration reverse data: a case study in Taihu Lake

The problem of algal bloom caused by eutrophication has attracted global attention. Many scholars have studied the problem associated with algae bloom, but few have carried out dynamic monitoring, instead focusing on the formation mechanism of cyanobacteria. For our study of the Taihu Lake in China, we used Moderate-Resolution Imaging Spectroradiometer (MODIS) and Landsat remote sensing image data from 2017 to establish a prediction model. First, we used MODIS data to retrieve the concentration of N, P, and chlorophyll a in water. Then, we applied the analytic hierarchy process (AHP) model to the inversion results to construct the diffusion potential index. Finally, we used C# to compile the cellular automata (CA) model. We found that the distribution of cyanobacteria predicted by our method was consistent with the algal bloom situation of Taihu Lake in 2017. The results showed that the method effectively predicts the dynamic transfer of cyanobacteria from outbreak to diffusion in a short period of time, which can help decision-makers monitor lake health.

     

Water mass interaction in the confluence zone of the Daning River and the Yangtze River—a driving force for algal growth in the Three Gorges Reservoir

Increasing eutrophication and algal bloom events in the Yangtze River Three Gorges Reservoir, China, are widely discussed with regard to changed hydrodynamics and nutrient transport and distribution processes. Insights into water exchange and interaction processes between water masses related to large-scale water level fluctuations in the reservoir are crucial to understand water quality and eutrophication dynamics. Therefore, confluence zones of tributaries with the Yangtze River main stream are dedicated key interfaces. In this study, water quality data were recorded in situ and on-line in varying depths with the MINIBAT towed underwater multi-sensor system in the confluence zone of the Daning River and the Yangtze River close to Wushan City during 1 week in August 2011. Geostatistical evaluation of the water quality data was performed, and results were compared to phosphorus contents of selective water samples. The strongly rising water level throughout the measurement period caused Yangtze River water masses to flow upstream into the tributary and supply their higher nutrient and particulate loads into the tributary water body. Rapid algal growth and sedimentation occurred immediately when hydrodynamic conditions in the confluence zone became more serene again. Consequently, water from the Yangtze River main stream can play a key role in providing nutrients to the algal bloom stricken water bodies of its tributaries.     

Cyanobacterial bloom expansion caused by typhoon disturbance in Lake Taihu China

It remains unclear why the area of a cyanobacterial bloom increases in a shallow lake after a typhoon passes. In this study, the mechanisms of cyanobacterial bloom expansion were investigated by studying meteorological factors, water quality, algal biomass, and bloom area in Lake Taihu before and after typhoons (2007–2016). Our results showed that typhoon-induced sediment resuspension caused a short-term increase in nutrients, but nutrients returned to pre-typhoon levels after the typhoon passages. The short-term nutrient release during a typhoon did not result in an obvious increase in Microcystis cell density in two bays of Lake Taihu (Gonghu and Meiliang). Under strong winds, Microcystis aggregates were uniformly distributed in the water column downwind and then dispersed into different directions by wind-driven currents. In particular, Microcystis in the surface water were transported to the center of Lake Taihu. After a typhoon, dispersed Microcystis refloated and formed blooms. Thus, the bloom area was enlarged compared with before a typhoon. Several days after a typhoon, the bloom area gradually reduced as a result of a steady breeze on the horizontal accumulation of Microcystis.

     

环境因子对汾河水上公园再生水中藻类生长的影响

实验根据太原市气候状况选取了不同温度和光照梯度条件,根据实验水质特征选取了不同的氮磷浓度值,研究了温度、光照、氮磷营养盐等环境因子对再生水回用于景观用水产生的主要藻类小球藻形成水华的影响效果。结果表明,温度升高、光照强度增加和光照时间延长可促进小球藻的生长繁殖;氮磷比对小球藻的生长影响较大,其中,小球藻在氮磷比为10：1-30：1时生长繁盛,氮磷比为44：1时生长受到抑制,即磷作为限制性营养盐,可抑制水华的发生;pH和溶解氧的变化趋势与藻细胞数的变化趋势一致,可作为水体发生水华的快速监测指标。     

Deacidification effect of the litter layer on forest soil during snowmelt runoff--laboratory experiment and its basic formularization for simulation modeling

The forest soil ecosystem can buffer and neutralize acidic airborne pollutants to some extent, but extensive acidification degrades the soil ecosystem. Several investigations have shown that surface flows often show particularly low pH values in rivers and lakes during snowmelt and that this acidification phenomenon takes place in a short time frame. Acid water from snowmelt first makes contact with the litter layer in the soil ecosystem. Therefore, a laboratory experiment was performed to study the impact of forest litter on the chemical composition of the water solution. The experiment presented in this paper confirmed that deacidification with a little leachate of organic matter is caused by cation exchange not only in upper mineral soil but also in the litter layer and that leachate of labile Al is restrained in the presence of litter. An attempt was made to incorporate these factors into the biogeochemical module of the model (ILWAS) to accurately estimate damage by acidification.