Removal Rate of Phosphorus by Different Constructed Wetland Substrates

[ Objective] The study aimed to discuss the removal rate of phosphorus by different constructed wetland substrates. [ Methed] Based on static experiments, we analyzed the removal rate and characteristics of phosphorus by different constructed wetland substrates like steel slag, cin- der slag, shale, boiler slag, soil and gravel. [ Result~ The maximum adsorption of phosphorus by various substrates showed as follows, steel slag 〉 cinder slag 〉 shale 〉 boiler slag 〉 soil 〉 gravel. When the initial concentration of phosphorus was 5 mg/L, the removal rate of phosphorus by the steel slag, cinder slag, shale, boiler slag, soil and gravel was 99.76%, 85.8%, 71.2%, 63.0%, 46.8% and 11.7% respectively. It is suggested that shale and boiler slag can be used as the substrate of subsurface-flow constructed wetlands; cinder slag can be chosen as a renewable sub- strate for intensifying phosphorus removal; steel slag could be used at the end of subsurface-flow constructed wetlands for treating TP in outflows. [Concluslon] The research could provide theoretical references for choosing a suitable substrate for constructed wetlands to remove phosphorus in future.

Effect of Hydraulic Loading Rate on the Efficiency of Effluent Treatment in a Recirculating Puffer Aquaculture System Coupled with Constructed Wetlands

Constructed wetlands(CWs) were integrated into an indoor recirculating aquaculture system of obscure puffer(Takifugu obscurus) for effluent treatment. The effect of hydraulic loading rate(HLR) on the efficiency of effluent treatment by CWs was examined for over a month. The CWs were operated under brackish conditions(salinity 7.4–7.6) at 3 different HLRs(0.762, 0.633, and 0.458 m d–1) 3 times, 10 days each. Overall, the CWs exhibited high efficiency in removal of total ammonium nitrogen(by 81.03–92.81%) and nitrite nitrogen(by 99.40%–99.68%). The efficiency of CWs in removal of total ammonium nitrogen, nitrate nitrogen, total Kjeldahl nitrogen, total phosphorous, and total suspended solids(TSS) increased with the decrease of HLR. The CWs operated at the 3 HLRs in a decreasing trend proves to be effective, providing a useful method for effluent treatment in commercial puffer aquaculture systems.

长江大保护试点城市某污水处理厂尾水湿地净化效果研究

为探寻污水处理厂配套尾水湿地净化效果,以长江大保护试点城市某污水处理厂尾水湿地为例,通过现场调查与采样,分析湿地出水水质特征,探讨影响湿地污染物去除效率因素。结果表明:尾水湿地出水COD、NH_(3)-N及TP浓度满足设计目标,潜流湿地对COD去除率较高,表流湿地对氨氮及磷的去除率较高,优于涵养塘;湿地实际运行水力负荷、水力停留时间和污染物负荷与设计值不符,影响污染物去除效果;据此提出湿地运行优化建议,促进湿地深度脱氮除磷,提升尾水湿地效能;运行优化可提高潜流湿地污染物去除率,同时污水处理厂减少碳排放94.74 gCO_(2)m^(3)。研究结果可为该尾水湿地运行管理及长江大保护试点城市系列污水处理厂配套尾水湿地设计与运维提供参考。

洞庭湖湿地短尖薹草(Carex brevicuspis)种群克隆生长对泥沙淤积的适应

泥沙淤积是影响湿地植物生存和生长的重要因素。克隆植物是湿地生态系统的主要植物类型之一。在自然水文条件下,湿地克隆植物种群对不同淤积速率的响应研究相对较少。本研究以洞庭湖湿地优势克隆植物短尖薹草(Carex brevicuspis)为对象,通过连续3年的野外控制实验,研究了不同淤积速率(0、2、4、6 cm/a,分别对应对照组,低、中和高淤积速率组)对湿地克隆植物种群的影响。结果表明:淤积速率对短尖薹草的种群密度影响显著,淤积处理的密度显著低于对照处理。随着淤积速率的增加,密度下降,地下/地上生物量比增加,高淤积速率下种群的密度最低,地下/地上生物量比最高。与对照处理相比,泥沙淤积促进了更多的短根(<10 cm)、长根茎(≥1 cm)和游击型克隆分株的形成,长根茎的长度随淤积速率的增加而增加。高淤积速率下的长根茎数量较低,但其根长最长,表明其克隆生长策略由密集型向游击型转变。由此可见,短尖薹草种群可通过对密度、生物量分配、根系长度和克隆生长策略的调节,有效地应对不同泥沙淤积速率的影响。

季节冻融对湿地土壤有机碳矿化速率及酶活性的影响

【目的】为探究季节性冻融作用对湿地土壤有机碳矿化速率及酶活性的影响,本研究选取三江平原洪河国家自然保护区内小叶章湿地、受人类活动干扰湿地和水稻田0~20cm和20~40cm土壤作为研究对象。【方法】采用室内模拟冻融的方法,探索冻融作用影响下湿地土壤有机碳矿化速率、土壤有机碳及酶活性的变化特征。【结果】实验结果显示,经过冻融循环矿化培养后,3种湿地土壤总碳的矿化率均低于0.55%,且冻融循环降低了3种湿地不同层土壤有机碳矿化总量。3种湿地土壤矿化总量均降低,表现为UDAW>DDAW>RP。冻融循环明显刺激了CH_(4)的累积释放量,在深层表现最明显。经过冻融处理的3种湿地土壤可溶性有机碳(DOC)含量高于未经冻融处理的对照(check,CK);而土壤可溶性有机碳(MBC)浓度和纤维素酶、淀粉酶、蔗糖酶活性均低于CK,且不同类型土壤表现为UDAW>DDAW>RP。【结论】冻融循环降低了湿地土壤有机碳矿化总量,但却提高了深层土壤中甲烷的矿化速率;经过冻融循环后,土壤DOC含量增加,相反却降低了土壤MBC含量和3种土壤酶活性。

青海湖流域沼泽湿地地表能量平衡特征分析

地表能量平衡是地气相互作用研究的重要内容,对能量交换、物质循环、气候环境变化、生物多样性等方面均具有重要意义。青海湖流域是青藏高原生态安全的重要屏障,沼泽湿地是流域内主要的生态系统类型,但针对青海湖流域沼泽湿地能量平衡方面的研究较少。基于此,本研究利用2019年瓦颜山综合观测场获取的能量平衡观测数据,分析了青海湖流域高寒沼泽湿地地表能量平衡变化特征。结果表明:瓦颜山沼泽湿地地表辐射通量均具有显著的季节变化特征,向下和向上短波辐射通量表现为春季>夏季>秋季>冬季;净辐射、向上和向下长波辐射通量表现为夏季最大,春、秋季次之,冬季最小。能量平衡特征具体表现为净辐射主要被潜热通量和感热通量消耗,占比分别达全年有效能量的60.6%和35.3%,夏、秋季主要消耗潜热通量,冬、春季主要消耗感热通量。沼泽湿地相较于青藏高原其他下垫面,地表潜热通量在夏、秋季占比更大,可占有效能量的75%以上。瓦颜山沼泽湿地全年地表能量闭合率0.69,冻结期和非冻结期闭合率分别为0.51和0.74。

西藏拉鲁湿地水质净化功能研究

为研究拉鲁湿地对水环境的净化效果,本文通过对拉鲁湿地入水口、出水口不同污染物的浓度对比,分析了不同季节拉鲁湿地对感官指标、氮磷营养盐、金属元素、阴离子等的去除率。结果表明:枯水期拉鲁湿地对水体中悬浮物、浊度、色度的最大去除率分别达46.4%、91.9%、100%,丰水期最大去除率分别达86.2%、95.7%、42.9%。拉鲁湿地水体在不同季节均存在不同程度的营养盐污染,枯水期总氮、氨氮、硝酸盐氮、总磷的最大去除率分别达60.7%、77.6%、74.6%、100%,丰水期分别达84.2%、100%、84.9%、100%。拉鲁湿地水体暂未受到重金属污染,但对金属元素仍具有显著的净化作用,其综合去除率从大到小依次为:Pb(100%)>Fe(96.4%)>Mn(91.0%)>As(83.3%)>Cu(82.4%)>Zn(79.8%)>Co(53.6%)>V(49.0%)>Mo(38.7%)>Ni(36.4%)。拉鲁湿地对水体中阴离子也有一定的净化作用,枯水期氟化物、硫酸盐的最大去除率分别为20.0%、3.28%,丰水期最大去除率分别为20.0%、27.1%。由于水温、植物及微生物丰度的影响,丰水期拉鲁湿地的净化能力明显优于枯水期。

长江口滨海湿地有机碳循环过程及影响因素研究进展

滨海湿地是“蓝碳生态系统”的重要组成部分。综述了长江口滨海湿地土壤有机碳时空分布及含量、碳汇速率、有机碳横向输入输出通量及量化方法、有机碳循环定量分析模型以及有机碳储量和组分对不同影响因素所做出的动态响应规律,发现在土壤有机碳水平空间分布上,崇西湿地>崇明东滩>九段沙>南汇潮滩;有机碳通量和浓度变化主要受到植物生物量和结构、水和土壤的理化性质、陆源输入和潮汐动力、间隙水交换以及人类活动和全球气候变化的影响。未来应加强长江口湿地土壤碳库和有机碳输运通量统一观测,准确量化各主要因素对有机碳的贡献,这对研究盐沼湿地的碳循环机理和碳汇评估具有重要意义。

北京湿地生态系统服务价值测度及演变分析

湿地生态系统服务价值的精准评估可为决策者平衡生态环境和经济发展之间的关系提供决策依据。该文通过市场价值法、重置成本法、旅行价值法等多种经济评估方法来估算湿地生态系统服务价值。研究结果表明:1984—2020年,北京湿地生态系统服务价值量呈波段式增长,由1984年的532.66亿元增长到2020年的1856.55亿元,其中20世纪90年代湿地生态系统服务价值快速增加,但随着社会经济发展的影响而大幅下降。2004年后湿地生态系统服务价值开始逐年提升,且维持高位水平。单项价值中北京湿地气候调节和调蓄洪水服务价值最高,休闲旅游服务价值量呈指数形增长,其他各项湿地生态系统服务价值相对稳定。研究结果可为未来城市规划和生态保护提供重要参考。

基质及植物对人工湿地处理农村生活污水的影响

用菖蒲、芦苇2种植物和石英砂、活性炭、煤矸石3种基质构建了6套人工湿地系统,分别命名为装置1#,2#,3#,4#,5#,6#,探究了植物、基质及水力停留时间对处理农村生活污水效果的影响。结果表明,随着水力停留时间的增加,6套装置系统对各污染物的去除效果均越来越好,当水力停留时间为48 h时,6套装置系统对各污染物的去除效果达到最佳。菖蒲-活性炭3#装置在48 h水力停留时间下,化学需氧量(chemical oxygen demand,COD)、氨氮(ammonia nitrogen,NH_(4)^(+)-N)、全磷(total phosphorus,TP)的去除率分别为97.34%,92.19%,79.50%,出水水质达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级B标准及以上,说明该系统可用于农村生活污水处理。

云南省沼泽湿地资源动态变化分析

以云南省湿地资源监测数据为基础,利用动态度、相对变化率模型,系统地对2001—2021年间云南省沼泽湿地面积、空间分布特征及其影响因素进行分析。研究结果表明,2012年较2001年云南省沼泽湿地面积迅速增加,增量为2.83万hm^(2);2012—2021年间云南省沼泽湿地面积呈波动型增加趋势,增量为8366.84万hm^(2),但各沼泽湿地型的变化趋势存在差异,其中草本沼泽面积增加4309.58 hm^(2),灌丛沼泽增加1099.80 hm^(2),森林沼泽增加4179.52 hm^(2),淡水泉增加1.83 hm^(2),沼泽化草甸减少1223.89 hm^(2);空间分布方面,滇西滇西北横断山脉高原湿地区、滇中和滇东高原湖盆湿地区、滇南中山山原河流湖泊湿地区在此时期沼泽湿地面积均呈增加趋势,滇东北中山深切割河流高原沼泽草甸湿地区、滇东南岩溶山原湖泊河流湿地区以及滇西南中低山宽谷河流湖泊湿地区在此时期沼泽湿地面积均呈减少趋势,各湿地区变化趋势具有差异性。沼泽湿地资源变化原因主要与人为因素及自然因素有关。

Geographical Variation and Influencing Factors of Spartina alterniflora Expansion Rate in Coastal China

Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical variation of its expansion rate in coastal China,we selected 43 S.alterniflora sites from Tianjin Coastal New Area to Beihai.The area expansion rate,expansion rate paralleling and vertical to the shoreline were analysed based on Landsat images and field survey in 2015.Simple Ocean Data Assimilation(SODA)and climate data were collected to statistically analyse the influential factors of expansion rate.Results showed that significant difference of S.alterniflora area expansion rate among different latitude zones(P<0.01),increasing from 6.08%at southern(21°N–23°N)to 19.87% in Bohai Bay(37°N–39°N)along latitude gradient.There was a significant difference in expansion rate vertical to shoreline in different latitude zones(P<0.01)with the largest occurring in Bohai Bay(256m/yr,37°N–39°N),and showed an decreasing tendency gradually from north to south.No significant difference and latitudinal clines in expansion rate paralleling to shoreline were observed.Expansion rate had significant negative correlation with mean seawater temperature,the lowest seawater temperature,current zonal velocity and meridional velocity and presented a reducing trend as these biotic factors increased;however,they were not significantly correlated with the highest seawater temperature and mean seawater salinity.We identified significant correlations between expansion rate and annual mean temperature,the lowest temperature in January and annual precipitation,but there was little correlation with annual diurnal difference in temperature and the highest temperature in July.The rapid expansion rate in high-latitude China demonstrated a higher risk of potential invasion in the north;dynamic monitoring and control management should be established as soon as possible.

Enhancing treatment efficiency of swine wastewater by effluent recirculation in vertical-flow constructed wetland

Livestock wastewater has been a major contributor to Chinese cultural eutrophication of surface waters. Constructed wetlands are under study as a best management practice to treat wastewater from dairy and swine operations, but the removal efficiency of pollutants is relatively low. Enhancing the treatment efficiency of livestock wastewater by effluent recirculation was investigated in a pilot-scale vertical-flow constructed wetland. The wetland system was composed of downflow and upflow stages, on which narrow-leaf Phragmites communis and common reed Phragraites Typhia are planted, respectively; each stage has a dimension of 4 m^2 （2 m × 2 m）. Wastewater from facultative pond was fed into the system intermittently at a flow rate of 0.4 m^3/d. Recirculation rates of 0, 25%, 50%, 100% and 150% were adopted to evaluate the effect of the recirculation rate on pollutants removal. It shows that with effluent recirculation the average removal efficiencies of NH4-N, biological oxygen demand （BOD5） and suspended solids（SS） obviously increase to 61.7%, 81.3%, and 77.1%, respectively, in comparison with the values of 35.6%, 50.2%, and 49.3% without effluent recirculation. But the improvement of TP removal is slight, only from 42.3% to 48.9%. The variations of NH4-N, dissolved oxygen（DO） and oxidation-reduction potential（ORP） of inflow and outflow reveal that the adoption of effluent recirculation is benefi- cial to the formation of oxide environment in wetland. The exponential relationships with excellent correlation coefficients （R2 〉0.93） are found between the removal rates of NH4-N and BOD5 and the recirculation rates. With recirculation the pH value of the outflow decreases as the alkalinity is consumed by gradually enhanced nitrification process. When recirculation rate is kept constant 100%, the ambient temperature appears to affect NH4-N removal, but does not have significant influence on BOD5 removal.

Sedimentation rates in the Wanggang salt marshes,Jiangsu

Coastal salt-marshes represent an important coastal wetland system. The total area of coastal wetlands exceeds 5000 km2 in Jiangsu Province, China, but it is decreasing rapidly in response to the intense reclamation activities and coastal erosion along a part of the coastline. Hence, two types of plants, Spartina angelica and Spartina alterniflora, were introduced successively into the Jiangsu coastal areas, in order to protect the coastline from erosion and to increase the accumulation rate. Pb-210 and Cs-137 analyses were carried out for sediment samples from the salt-marshes of Wanggang to determine the sedimentation rate, on the basis of an evaluation of the background activity values and the factors affecting the enrichment of Pb-210. Analysis of a typical sediment column of the tidal flat shows that there is weak absorption of Pb-210 in the silt-dominated sediment. Because of the influences of factors such as storm events, bioturbation, material sources and analytical error, some abnormal data points appear in the Pb-210 record. After ignoring these data the calculated sedimentation rate was 3.3 cm yr-1 on average. Based upon analysis of the Cs-137 dating, the rate since 1963 was 3.1 cm yr-1 on average, similar to the data by Pb-210 dating and the previous studies. The dating results show that there were three stages of sedimentation, with the most rapid accretion being taking place after Spartina angelica was introduced into the area. The study also shows that at the stage of Spartina alterniflora growth, the accretion rate was higher than on the flat surface with the same elevation without the cover of this plant.

滨海蓝碳湿地碳汇速率测定方法及中国的研究现状和挑战

滨海盐沼、红树林和海草床蓝碳湿地生态系统具有高效的固碳-储碳能力,准确测定滨海蓝碳湿地生态系统碳汇速率,对于评估滨海湿地碳中和能力、生态恢复新增碳汇规模及碳贸易至关重要。深入思考滨海蓝碳湿地生态系统碳汇定义的内涵,提出狭义碳汇和广义碳汇的概念,介绍沉积物碳累积+植被净初级生产力法以及生态系统碳通量收支法2个目前国际上应用最多的滨海蓝碳湿地碳汇速率测定方法,特别是深入分析作为开放系统的滨海盐沼生态系统和海草床生态系统碳汇速率测定面临的诸多问题与挑战,梳理中国红树林、滨海盐沼和海草床生态系统碳汇速率的测定结果及国家尺度滨海蓝碳湿地生态系统碳汇规模,最后提出中国在滨海蓝碳湿地碳汇速率测定实践中急需加强的基础研究领域,以期为科学地计量中国滨海蓝碳湿地生态系统碳汇速率与碳汇规模提供方法参考和技术支撑。

污泥生物炭强化人工湿地处理生活污水性能研究

为探究生物炭对人工湿地处理生活污水的强化作用,同时解决污泥的资源化再利用问题,以沸石和污泥生物炭为基质构建上行垂直流人工湿地系统,以沸石基人工湿地A为对照组,并设置2组不同生物炭投加量的湿地B和C[顶层填料V(生物炭)∶V(沸石)分别为1∶2和1∶1]。探究了污泥生物炭及其投加量对人工湿地脱氮除磷的强化效果,以及水力停留时间(HRT)对污染物去除效果的影响,并结合静态吸附试验和表征数据分析污泥生物炭对TP的吸附特性和机理。结果表明:污泥生物炭的添加显著提高了污染物的去除效果,与湿地A相比,湿地C对COD、TN、NH_(4)_(+)-N及TP的去除效果更好,去除率分别提高7.56、15.99、11.97和40.77个百分点;较长的HRT更有利于污染物的去除,当HRT为3 d时,湿地对污染物的去除效果更好;污泥生物炭对TP的吸附动力学符合准二级动力学方程,吸附等温线符合Langmuir模型,其对TP的最大吸附量达1.42 mg·g^(-1);吸附机理主要包括物理吸附、官能团络合及矿物质沉淀作用。研究表明,污泥生物炭的吸附量大且成本低,将其作为新型湿地填料具有良好的应用价值,对解决水污染问题也具有借鉴意义。

植物种类和入塘流量对塘堰湿地净化效果和水力性能的影响

塘堰湿地在我国南方灌区分布广泛,合理的湿地设计有利于提高其综合效益的发挥。以大理市洱海流域为典型区域,通过开展静态、动态去除试验及示踪试验,分析了植物种类(水葱、再力花、梭鱼草)和入塘流量(4、11 m^(3)/h)对塘堰湿地净化效果和水力性能的影响。结果表明:①梭鱼草湿地的氮磷净化效果优于水葱湿地,优于再力花湿地;水葱湿地的水力性能优于梭鱼草湿地,优于再力花湿地;综合净化效果和水力性能,水葱优于梭鱼草,优于再力花。②入塘流量从11 m^(3)/h减小到4 m^(3)/h时,湿地的总氮去除率从17.8%增加到32.7%,总磷去除率从19.9%增加到28.6%,有效容积率从0.60增加到0.77,莫里尔离散指数从3.12增加到3.59,净化效果和水力性能提高,水流的短路情况减少,但混合程度增加。③湿地前半部分的氮磷去除率占整体的65%~87%,有效容积率在0.85以上,净化效果和水力性能优于湿地整体。

基于多源数据的水神堂泉及周边湿地演化研究

湿地作为地球之肾,具有重要的社会、环境和经济价值。湿地退化往往引发一系列生态环境问题。为系统研究山西历史名泉——水神堂泉及其周边湿地的变化过程,基于历史开放卫星数据,使用支持向量机、随机森林、梯度提升树、最小距离、分类回归树算法和GEE深度神经网络对1984-2020年每隔5年的遥感影像数据进行湿地提取,分析水神堂泉周边湿地的历史变化趋势。采用多元统计方法研究水神堂泉水流量和湿地分布面积的关系,结果表明,1958年至今,区域内年降水量呈总体下降趋势,降幅为1.12 mm/a;泉水流量持续下降,全县湿地面积总体呈萎缩趋势,由1984年的59.82 km 2衰减到2020年的14.11 km 2,萎缩速率为1.27 km 2/a。水神堂泉水与周边湿地呈现同存共生的关系,泉水流量和降水量是影响湿地面积的主要因素,泉水流量的减少是湿地面积衰减的最主要原因。

水力负荷和填料对华南冬季条件下潮汐流人工湿地去除氨氮的影响

供氧不足是导致传统人工湿地硝化速率和水力负荷低的关键因素。此外,低温条件下微生物活性下降会进一步加剧该问题。针对上述情况,构建两组供氧能力强的潮汐流实验柱,在华南冬季条件下考察水力负荷和填料对系统NH_(4)^(+)-N去除效率的影响。结果表明,NH_(4)^(+)-N去除负荷与水力负荷成正比。以沸石与碎石混合填充的潮汐流实验柱(TFCW-Z)对NH_(4)^(+)-N的平均去除率(67.20%~77.28%)显著高于以碎石填充的实验柱(TFCW-G)NH_(4)^(+)-N平均去除率(43.23%~51.77%)(p<0.05)。在日平均温度为6~19.5℃,水力负荷为4 m/d条件下,TFCW-Z出水中NH_(4)^(+)-N质量浓度始终低于黑臭水体标准值8 mg/L,此时NH_(4)^(+)-N平均去除率为67.20%,NH_(4)^(+)-N平均去除负荷高达47.96 g/(m2·d),表明潮汐流人工湿地在华南地区黑臭水体治理中具有良好的应用前景。