Water quality in forest and village ponds in Burkina Faso(western Africa)

Forest ecosystems help conserve the quality of water resources in aquatic habitats. The conservation of biological diversity in aquatic and terrestrial ecosystems remains a communal concern. Aquatic ecosystems and resources are vulnerable but can be preserved and protected by forests. In sub-Saharan regions of Africa, water from ecosystems such as ponds still play important role in the livelihood of local populations. Water from temporary ponds is used by local populations for multiple needs; however, in this part of the world, the population is increasing, thus increasing human needs and activities and land use in the region. Land-use changes lead to deforestation, land degradation and the decline in freshwater, affecting human health and well-being. Forest degradation leads to the decline in ecosystem goods and services, particularly those related to watersheds. This study conducted in eastern Burkina Faso aimed to assess water quality of temporary ponds in protected forest areas (reserves) and surrounding villages. It was conducted in 61 temporary ponds where physical, chemical and biological variables were measured, such as water surface area, depth, transparency, macrophyte cover, pH, dissolved O2, conductivity, nutrient concentrations and algae biomass. The results showed that at p < 5%, water surface area (p = 0.02), depth (p = 0.00), nutrient content (p = 0.00), and algae biomass (p = 0.04) were significantly higher outside reserves than inside reserves. In contrast, macrophyte cover (mean cover percentages 53 vs. 44.5%) and water transparency (p = 0.02) were higher inside reserves. The variations in conductivity and pH were not significant. All trends showed the influences of human activities on water characteristics and the role forests and land cover had in preventing negative human impacts and disturbance of temporary ponds. Forests and land cover are important to water quality conservation and algae biomass regulation in temporary ponds. Protecting and managing forests is therefore an essential part of future strategies for limiting algal blooms and their negative consequences, maintaining water quality and providing clean water to citizens.

Biological Effects of Nutrient Nualgi on the Water Ecological Environment in Culture Pond

In order to study the short-term effects of Nualgi on water quality and phytoplankton in fishpend, we conducted continuous and regular surveys on the phytoplankton community and the water quality indexes in four groups. The four groups were a Nualgi group （ M1 ）, a diatom group （ M2 ）, a Nualgi and diatom group （M3）, and a control group （C）. The results showed that there were no significance differences in pH, dissolved oxygen （DO）, total nitrogen （TN） and total phosphorus （TP） among the four groups. The IP concentration of groups MI and M3 was significantly lower than that of groups M2 and C, indicating that Nualgl can reduce the IP concentration of water. The concentrations of NH4＋ -N, NO2- -N and CODMn, of groups M1 , M2 and M3 were sigeificantly lower than those of group C, suggesting that both Nualgi and dominant diatom species can adjust water quality by reducing the concentrations of NH4＋ -N, NO2- -N and CODMR. In this test, we identified 186 species that belonged to 109 genera of seven phyla. Among them, 86 species were Chlorophyta, 48 were Bacillariophyta, 27 were Cyanophyta, 17 were Euglenophyta, three were Dinophyta, three were Cryptophyta and two were Chrysophyta. Both diatom species and Nualgi can promote the growth of Bacillariophyta, restrain the growth of Chlorophyta and Cyanophyta, and thus change phytoplankton community structure. The biomass of Bacillariophyta in groups M1, M2 and M3 was larger than that in group C from the 20th d of the experiment, while the biomasses of Chlorophyta and Cyanophyta were lower than that in group C. Melo- sira granulata became the dominant algae species in groups M1, M2 and M3 , while Coelastrum microporum and Crucigenia tetrapedia were the dominant algae species in group Conly. Scenedesmus quadr/cauda became the dominant algae in groups M1 , M2 and C. There was no remarkable difference in diversity index among the four groups. The Shannon-Wiener index in all the four groups were all above 2.00, suggesting that the addition of Nualgi or diatom species did not affect the species diversity in this experiment.

Cr （Ⅲ） Removal from Synthetic Waste Water by Using Water Pond Mud

The pollution of aquatic ecosystem by heavy metals has assumed serious proportions due to their toxicity and accumulative behavior. The toxicity metal is dependent on its chemical form and therefore removal of metal is more meaningful than the estimation of its concentrations. In this study, the batch experiments were carried out under 30℃ to study the effect of pH, initial Cr concentration, adsorbent dose and contact time on the removal of Cr （lII）. The maximum adsorption efficiency （99%） was observed when 1.5 g of pond mud was used for removal ofCr （Ⅲ） from test solution containing 150 mg·Cr / 100 ml. The optimal pH and contact time recorded during the study were 6 and 10.0, respectively.

Application of polymeric flocculant for enhancing settling of the pond ash particles and water drainage from hydraulically stowed pond ash

Delayed settling of the ash particles and poor drainage of water from the pond ash are the major problems faced during the hydraulic stowing of pond ash. In this study the effect of polymeric flocculant on settling of the ash particles and drainage of water during pond ash stowing are investigated. In addition, the parameters, viz. drainage and absorption of water during pond ash stowing are quantified by stowing a mine goaf model with pond ash slurries of five different concentrations added with and without flocculant. The study revealed that addition of only 5 10 6 of Sodium Carboxymethyl Cellulose (Na-CMC) flocculant with the pond ash slurries during stowing offers best result in terms of quicker settling of the ash particles and enhanced water drainage from the hydraulically stowed pond ash. Besides, it resulted in drainage of more than 85% of the total water used in the initial 45 min of stowing. The improvement in drainage is caused due to coagulation and flocculation of the pond ash particles because of charge neutralization and particle-particle bridging. This study may provide a basis for estimating the drainage and absorption of water during the real pond ash stowing operation in underground mines.

Chemical Compostion of Earthen Pond Feed from Spring Water, in Asaba Campus, Asaba, Delta State, Nigeria

Sound pond productivity accompanied with adequate fish health is maintained, when water quality parameters are conducive. The study evaluated the chemical composition of a pond feed from spring water, in Asaba Campus. Sampling was carried out from September 2011 to February 2012 on a monthly basis. Surface water samples were collected between the hours of 7：00-9：00 am from the pond on each sampling day. Hydrogen-ion-concentration was in the range of 6.5 to 8.0 units. Dissolved oxygen was the highest in February 2012 with a value of 11.0 mg/L while it was the lowest in December 2011 with a value of 9.0 mg/L. Biological oxygen demand ranged from 3.5 to 5.0 mg/L. The chemical oxygen demand was the highest in December （10.00 mg/L） and lowest between January and February （8.0mg/L）. The highest alkalinity was observed in October with a value of 1.05 mg/L and lowest in December with a value of 0.042 mg/L. Conductivity values ranged from 0.075 to 0.12 μS/cm. Total phosphorus was the highest in October with a value of 1.01 mg/L and lowest in December with a value of 0.83 mg/L. Total dissolved solids ranged from 90 to 105 mg/L. Values of physco-chemical parameters revealed that the pond was not polluted. Water quality analysis of the aquatics is of economic advantage to the fish farmer, hence, the need for its assessment at regular intervals. This is a quality assurance process that assures early dictation of toxic substances and mitigation processes to adopt before problems arise. In this way, the good health of organisms in the aquatic ecosystem and those of human dependent on them are guaranteed.

Community Structure of Phytoplankton in Pond Industrial Eco-aquaculture System for Megalobrama amblycephala

In order to find out the change pattern of phytoplankton community structure in pond industrial eco-aquaculture system and explain its ecological mechanism,tests were carried out using Megalobrama amblycephala as aquaculture species with two stocking densities.Shannon-Wiener diversity index and Pielou uniformity index were used to study the phytoplankton community structure in aquaculture area( including low stocking density aquaculture area and high stocking density aquaculture area),inlet area,outlet area,purification area,recirculation area,back area of the pond industrial eco-aquaculture system.The results showed that a total of 92 species of 5 phyla were identified,including 46 species of Chlorophyta,15 species of Cyanophyta,15 species of Euglenophyta,10 species of Bacillariophyta,5 species of Cryptophyta,and 1 species of Pyrrophyta.The numbers of phytoplankton species,biodiversity indexes,uniformity indexes,Chlorophyta biomass and its proportion in total phytoplankton followed the order of inlet area,purification area,recirculation area,back area > low stocking area > high stocking area > outlet area.The total biomass of phytoplankton,Cyanophyta biomass and its proportion in total phytoplankton followed the order of inlet area,purification area,recirculation area,back area < low stocking area < high stocking area < outlet area.However,all these parameters showed no significant differences or change rules among inlet area,purification area,recirculation area,back area.It could be concluded according to the biodiversity that the water quality in outlet area was at middle pollution level,the water quality in high stocking area was in light pollution level,and the water quality in other 5 areas were at clean level,which suggested that the water quality was in good states except that in outlet area,and the pond industrial eco-aquaculture system functioned well.

南方灌区沟渠塘库系统水平衡模拟模型研究

定量描述南方多水源灌区灌溉水转化机制是实现灌区水资源高效利用的基础。本文以湖北省漳河灌区内部的杨树垱流域为例,考虑其内部的空间异质性,对流域划分灌溉子区并对灌排系统进行水平和垂向概化,根据水量平衡原理研发多个水平衡子模块,构建沟渠塘库系统水平衡模拟模型。根据2021-2022年典型塘堰和内部水库的实测逐日水位资料,利用拉丁超立方抽样法和偏相关分析法对模型参数进行敏感性分析,并在不同流域尺度上对模型进行率定和验证。模拟结果的Nash-Sutcliffe系数(0.72~0.99)、均方根误差(0.09~0.20 m)和平均绝对误差(0.08~0.14 m)表明模型模拟效果较好,与传统灌区分布式水平衡模拟模型相比,该模型可以在满足较高精度的同时,更为全面地描述灌区水转化过程,为定量描述流域内灌溉系统的水转化过程提供新途径。

生态塘-潜表流复合人工湿地对抚仙湖入湖河流水质净化效应及途径

为探明人工湿地在流域面源污染治理和高原湖泊及临湖流域水生态环境保护中的效用,本研究以尖山河流域生态塘-潜表流复合人工湿地11级功能区和4种植物为研究对象,通过测定2021年雨季6场典型降雨后各功能区污染物负荷、一个刈割周期内植物各器官及其对应土壤的氮磷含量,分析其氮磷积累量、富集系数和迁移系数的变化特点,深入探讨系统对不同面源污染物的去除效应及途径.结果表明:①生物沉砂塘对悬移质的沉积率范围为27.75%~55.00%,且逐级递减,系统对面源污染物的去除率在44.40%~78.87%之间,末端分区效果更为显著.②植物根区土壤作用(贡献率为59%~74%)是人工湿地氮去除的主要途径,植物吸收转化(贡献率为32%~42%)是磷去除的主要途径,在高污染负荷输入条件下悬移质削减率及污染物净化效应更优.③人工湿地植物营养元素的富集和株内迁移能力具有阶段性,氮、磷元素富集系数(分别为2.29~3.53、1.07~2.92)均大于1且向上迁移活跃,有利于修复环境污染.④单位面积氮磷去除速率均表现为表流湿地>潜流带状湿地,最优植物配置分别为再力花+旱伞草和香蒲+旱伞草.研究显示,合理调配土壤与植物比例及组合,高效利用不同植物配置路线对元素的敏感差异性,对入湿水体进行预处理和采用多功能、多塘系结合的人工湿地设计可稳定发挥水质净化效用.

田-沟-塘系统纳洪减污效应研究进展

针对南方地区水资源时空分布不均、水旱灾害频发且极端气候加剧、农业用水效率不高且面源污染严重等水安全问题,探讨稻田、排水沟、塘堰组成的灌溉排水系统(简称田-沟-塘系统)的调蓄纳洪、协同减污效应,以期为灌区雨洪调蓄和节水减排提供理论参考。从灌区雨洪调蓄实际出发,对当前田-沟-塘系统的国内外研究工作和发展进行总结,对田-沟-塘系统承纳洪水、输水蓄水、优化调水、协同防控氮磷流失等基础理论和关键技术等问题进行阐述,提出了田-沟-塘系统的“虚拟水库”模式及其纳洪效应的模型模拟方法。目前关于田-沟-塘系统调水控水的研究还普遍停留在净化水质单方面效用上,水量调蓄方面则多以研究稻田、排水沟、塘堰单个体的水平衡过程为主,缺少田-沟-塘系统联合调度的系统研究,如何提高灌区粮食生产过程中雨洪调蓄利用仍缺乏系统思维和技术手段。未来的研究要进一步拓展和丰富田-沟-塘系统雨水调蓄利用和协同减污功能,揭示稻田作为“隐形蓄水池”的蓄水潜力以及田-沟-塘系统的调洪削峰减污能力。

南美白对虾养殖调温系统设计

以宁海县三门湾某工程为例,对养殖池水调温系统进行了设计。对养殖车间进行了热湿平衡分析,当池水温度恒定为27℃时,计算得到室内空气温度为25℃、相对湿度为85%,解决了工程应用时依靠经验数据确定室内空气温湿度的现状。对养殖池水耗热量进行了计算分析,确定了海水源热泵为养殖池水调温系统的冷热源。建立了圆形管道加热养殖池水的传热模型,计算了采用不同管道材质时所需的管道长度及初投资。对调温系统防腐蚀设计进行了介绍,除水管需要采用防腐蚀材料,热泵机组、水泵、阀门的主要部件也应选用耐腐蚀材料。该结果以期为类似工程养殖池水调温系统设计提供参考。

多级净化循环系统水泵联动控制方案设计

多级净化循环系统是一种应用于“立体种植+工厂化养殖”农业生产模式的水循环系统,文章提出一种多级净化循环系统水泵联动控制方案,可实现“养殖池—硝化分解池—回水池—养殖池”的水循环过程,既可以净化养殖用水水质,提高养殖用水的溶氧量,又能吸收水质中对养殖有害的氨氮、总磷等物质作为蔬菜的养料,供给蔬菜生长,最终实现一种生态农业的发展模式。

海水池塘跑道养殖系统中鱼类肠道及养殖环境的细菌群落研究

为查明海水池塘跑道养殖系统(IPRS)的不同生境中细菌群落特征以及不同群落间的相互作用关系,本研究采用16S rRNA基因高通量测序技术对IPRS中鱼类肠道、水体和沉积物的细菌群落组成和结构进行了研究。研究表明,鱼类肠道、水体和沉积物的细菌群落在结构和多样性上均存在显著差异。不同生境中细菌群落的优势组成不同,花鲈(Lateolabrax maculatus)肠道内相对丰度最高的菌门为厚壁菌门(Firmicutes, 57.92%),河鲀(Takifugu rubripes)肠道内为弯曲杆菌门(Campylobacterota, 41.17%),水体和沉积物中均为变形菌门(Proteobacteria),其相对丰度分别达到91.03%和48.06%。LEfSe分析表明,栖粪杆菌属(Faecalibacterium)、拟杆菌属(Bacteroides)和罗氏菌属(Roseburia)等20个菌属在花鲈肠道内显著富集;unclassified_Arcobacteraceae、普雷沃菌属(Prevotellaa)和罗尔斯顿菌属(Ralstonia)等12个菌属在河鲀肠道内显著富集;伍斯菌属(Woeseia)、Muribaculaceae和unclassified_Halieaceae等26个菌属在沉积物中显著富集;Clade_Ⅰa、Clade_Ⅲ和HIMB11等10个菌属在水体中显著富集。IPRS不同功能区的沉积物菌群结构也存在显著差异。其中,固体废物收集区与净水区的差别较大,Sva1033、uncultured_Desulfocapsaceae、unclassified_Flavobacteriaceae和unclassified_Rhodobacteraceae等一些能够降解有机物和去除氮、磷、硫等营养盐的细菌在固体废物收集区沉积物中大量富集,这一群落特征与其功能相匹配。鱼类肠道菌群与水体菌群相似度较小,而与沉积物菌群相似度较大。河鲀和花鲈肠道菌群与沉积物菌群的平均相似度分别为4.00%和2.85%,这表明河鲀肠道菌群受沉积物的影响更大。

Irrigation ponds:Possibility and potentials for the treatment of drainage water from paddy fields in Zhanghe Irrigation System

Excessive application of fertilizers and pesticides as well as discharge of undecontaminated and unrecycled waste of livestock and poultry into farmland has caused serious non-point source pollution (NSP) of farmland in China. With the traditional mode of irrigation and drainage in rice-based irrigation systems, the pollution of farmland drainage water has become more and more serious. Traditional irrigation and drainage systems only focus on issues concerning water quantity, i.e. the capacity of irrigation in drought and drainage in waterlogging period, yet have no requirement on water quality improvement. how to clean the water quality of farmland drainage through remodeling the existing irrigation and drainage systems has a very important realistic meaning. Pond is an important irrigation facility in rice-based irrigation systems in southern China, which has the functions of not only a storage of water from canals but also collections of surface runoffs and farmland drainage for recycling use. Such water storage features of pond provide the possibility and potential capacity for drainage water treatment by managing such features as treatment basins as the growth of aquatic plants as well as living of fishes, batrachia and microorganisms in pond forms a soil-plant-microorganism ecological system. To explore the potential capacity of pond for drainage water nutrient reduction, the Zhanghe Irrigation System of Hubei, a typical "melon-on-the-vine" system in southern China is selected as the research site. The results of pond survey and field experiments demonstrate that plenty of ponds are suitable for collecting and cleaning paddy field drainage, and the ponds are favorable in reducing N, P nutrients in the drainage water. Other issues, e.g. how to maximize such capacity and what strategies should be sought to make existing treatment basins hydraulically more efficient, are also discussed.

不同养殖模式下水体及鱼体中重金属分布规律的研究进展

重金属是一种来源于自然或人为的环境污染物,具有毒性、不可降解性和生物累积性,进入水生环境后会造成水体重金属质量浓度超标,导致鱼类等水生生物病变和死亡,通过食物链给人类带来潜在健康风险,一直以来是渔业养殖健康发展过程中需要重点关注的问题之一。文章基于当前鱼类主要养殖模式[池塘养殖、网箱养殖、循环水养殖系统(recirculating aquaculture systems,RAS)],综述了不同国家、不同鱼类养殖模式下重金属在养殖水体和养殖鱼体中的分布规律,以及重金属在养殖鱼体内不同组织器官的分布规律与含量变化特征,以期为不同鱼类养殖模式的选择及鱼类养殖重金属污染防治提供参考。

基于MODCYCLE分布式水文模型的区域产流规律

为了分析区域产流时空变化规律以及不同下垫面的产流特征,采用了具有物理机制的分布式水文模型——MOD CYCLE模型,并以天津市为例进行深入研究。该模型在综合考虑土壤、下垫面条件、降雨条件等多方面因素的基础上,采用修改后具有地表积水机制的Green-Ampt方程计算产流量。计算结果表明,1)1997-2004年天津市8a平均总产流系数约为16%,其中陆面产流系数不足10%。2)陆面产流主要集中在北部山区、中心城区及东部沿海地区;水面产流主要集中在中部及东南部地区。3)陆面产流中城市区产流系数最大,8a平均为44.1%;农村居民地的产流系数也较大,为24.5%;天然林草和河滩地的产流系数不足10%,农田由于田埂的作用几乎不产流。

水塘系统对农业流域水资源调控的定量化研究

本文以一个典型农业小流域为对象,定量化研究水塘系统对流域因作物需水引起的水资源短缺的调控功能。结果表明,六岔河流域的水塘系统蓄水容量6 72万m3,在不同水文年均能有效地调控流域水资源的时空分布,满足作物生长需求。六岔河流域的多数降雨径流被水塘系统截留,减少流域径流输出;在连续流过程中,流域径流峰值急剧降低。水塘系统能够截留日降雨强度为144mm降雨产生径流的90%,径流峰值大大降低。由此说明水塘系统是雨水资源可持续利用的一种有效方法。

对虾高位池循环水养殖系统对水质调控效果研究

为了改善高位池对虾养殖水质,降低养殖环境污染,提高产品质量安全,对自主研发的高位池循环水养殖系统调控对虾养殖水质的效果进行研究,设计了3个不同循环量(20m·3h-1,T1)、(40m3·h-1,T2)、(60m3·h-1,T3)水处理系统进行高位池试验。结果表明,不同处理量的循环水系统均能有效地降低水体中NH4+和NO2-,T1、T2、T3对NH4+的相对消除率分别为46%、56%、57%;对NO2-的相对消除率分别为38%、34%、54%;各处理组对NO3-均没有明显的消除作用。T1、T2对PO34-无消除效果,T3对PO34-的相对消除率为36%。T1对COD无消除效果,T2、T3对COD的相对消除率为9%、15%。综合比较可知,60m·3h-1循环水处理系统对改善水质效果最好,40m3·h-1次之,20m3·h-1最差。

池塘循环水养殖模式下养殖面积与净化面积的配比关系研究

为了详细计算池塘循环水养殖模式养殖面积和净化面积合理的配比关系,使养殖废水中氮、磷等富营养化物质的分级利用和水资源的循环使用更加合理。通过参照水生植物对养殖尾水中污染物的吸收能力和养殖鱼类的产排污系数,再结合淡水池塘养殖过程中水质管理的一般规律,给出了淡水池塘循环水养殖模式中养殖池塘面积和净化池塘面积之间配比关系的计算方法。以养殖草鱼为例,通过该计算方法,结果表明:以总氮的去除为例,养殖池塘和净化池塘的基本面积比为15:1;按养殖池塘所排放的污染物浓度计算,一亩净化池塘可以净化7.5亩养殖池塘;按养殖鱼类的产排污系数计算,一亩净化池塘可以净化27.8亩养殖池塘。不同的养殖产量、不同的养殖品种都会影响到净化池塘和养殖池塘面积比例,通过提高净化池塘的净化能力则可以减少净化池塘的使用面积,从而提高养殖效益。利用该计算方法来解释此前相关的研究实例,也证明是可行的。该计算模型的构建为今后在池塘循环水养殖模式构建中降低经济成本,为最终实现生态效益对经济效益的补偿提供了理论基础。

池塘养殖水质监控系统设计与实现

为了实现池塘养殖水质环境的自动化管理和控制,对养殖生产进行辅助决策,采用先进的计算机技术和传感技术、网络通信技术、自动控制技术等手段,开发池塘养殖水质监控系统,改变传统的养殖生产管理方式,促进水产养殖业的可持续发展。

生态工程化循环水池塘养殖系统

为研究解决池塘养殖污染、水资源浪费和水产品安全等问题,针对传统淡水鱼类池塘养殖特点,设计了一种生态工程化循环水池塘养殖系统,系统由生态沟渠、生态塘、潜流湿地和养殖池塘组成,面积比为1︰5︰3︰30,系统中池塘呈串联结构排列,池塘对角方向建设有水层交换过水设施,系统利用1级动力提升形成循环水流。在池塘养殖密度0.20～0.82kg/m3和系统水体日交换量10%～15%的情况下,水质检测结果表明,池塘养殖水体中的铵氮、亚硝态氮、硝态氮、总氮、总磷、化学需氧量(COD)等水质指标分别低于1.89、0.20、1.50、3.27、0.59、9.0mg/L,均低于对照池塘,并符合淡水池塘养殖用水标准。生态工程化设施水体净化效果研究表明,潜流湿地对养殖排放水体中总氮、总磷和COD的去除率分别高于52%、39%和17%;生态沟渠对养殖水体中总氮、总磷和COD的平均去除率超过18.35%、17.39%和18.18%;生态塘对养殖水体中总氮、总磷和COD的平均去除率分别为24.72%、26.32%和5.86%。与传统池塘养殖模式相比,生态工程化循环水池塘养殖系统可节约养殖用水63.6%,减少COD排放81.9%,有明显的节水、减排效果。