【作者】 贾悦；

【导师】 李秀珍；

【作者基本信息】 华东师范大学 ， 生态学， 2011， 硕士

【摘要】 水体富营养化问题已是当今世界面临的最主要的水污染问题之一。聚焦长三角地区水体治理难、富营养严重的问题,尤其针对陡直的水泥硬岸河道,恢复自然岸滩和湿地经济代价巨大,鉴于人工浮床技术治理污染河流不受水位限制,不造成河道淤积,只占水面不占地,可放可收易管理,还可以获得一定经济和社会效益,特别是运行高效,因此对该技术开展相关研究,对我国水体富营养化治理及水资源可持续利用具有重要的现实意义。目前,已有研究大部分以静态实验或封闭水体小试验为主,较少涉及河道现场实验,且仅有的现场试验,也只是局限于对浮床系统运行净化方面研究,而对浮床系统现场运行下的管理研究较少。本文针对与采收管理相关的问题开展研究,以期寻求合理有效的管理方式,对生物浮床高效运作具有重要的指导意义,可为该技术的高效应用提供科学依据。本文以空心菜为受试植物,采用野外实验和控制实验相结合的方法,对浮床生物进行不同采收周期(2周间隔、3周间隔、4周间隔)和留茬高度(野外试验为：15cm、25cm、35cm；控制试验：8cm、16cm、24cm)处理。野外实验主要通过观察分析植株新芽生长、生物量、茎叶比等变化,研究不同采收方式对浮床植物生物产出的影响；控制实验是针对浮床生物不同采收方式对水质净化效果设计的,主要通过对TN、NH4+-N、TP、CODcr等水质指标的测定分析,评价了不同采收方式对水质净化的功效。本论文主要研究成果如下：不同采收方式对生物产出的影响(1)采收后的植物仍能够适应过水河道环境,并在其生长周期内持续生长。经110 d的生长,分枝数提高了近5倍,最长根长27cm,平均根长15 cm,根系直径达11 cm。单株根鲜重可达146 g,每平米浮床根部可吸附颗粒物3.36 kg。(2)新芽生长速率随采收次数增多,均呈现先不断提高然后减小的趋势,变化幅度为0.54-3.7cm·d-1,对照组为1.63 cm·d-1。适当采收能提高新芽再生速率。单次收获生物量同新芽变化规律相似,即先逐渐增多然后减小,生物量增长速率变化幅度3.83～37.9 g·m-2·d-1。(3)从总生物量来说,每4周采收1次留茬25 cm、35 cm组的生物量(干重)产出最高,达2112 g·m-2；从茎叶比看,每2周采收1次3个留茬高度,及每3周采收1次留茬15 cm和25 cm方式收获植物茎叶比较佳；综合考虑产量和质量,及浮床便捷管理,每3周采收1次留茬15 cm的采收方式效果最佳,此时新芽平均生长速率1.88 cm·d-1,平均茎叶比小于1,总生物量1966 g·m-2。不同采收方式对水质净化效果的影响(1)TN含量在换水周期内随时间推移而不断降低。不论采收间隔,还是留茬高度对TN净化效果均有显著差异(P<0.05)。不采收组TN净化效果(78%)明显高于空白(48%)。从TN净化效果看,最佳采收方式是每3周采收1次留茬16cm或24cm,或者每4周采收1次留茬16cm,平均净化率80%左右。(2)TP含量在换水周期内随时间推移而不断降低。不论采收间隔,还是留茬高度对水体TP的去除效果均无显著影响(P>0.05),即采收不影响系统对TP去除的效果。浮床对氮(80%)的净化效果比磷(64%)好。(3) CODcr含量在换水周期内随时间推移呈不规则的上下波动变化。浮床系统对有机物的净化效果不明显,浮床植株采收不会影响CODcr含量变化。(4) NH4+-N浓度在换水周期内随时间推移不断降低。所有处理组对NH4+-N的净化率在95%以上,甚至接近100%。采收方式不影响NH4+-N的净化效果。更多还原

【Abstract】 Eutrophication is already one of the most major water pollution problems in the world today. It’s very hard to solve the serious eutrophication problem in theYangtze river delta. Due to the cement embankment, the cost is extremely high to restore natural banks and wetland. However, floating treatment wetlands (FTW) can offer the advantages of providing effective treatment, easy management and economic benefits, and occupying water surface only, without being constrained by the requirement of water depth. Thus, this technology has great practical significance for remidiation of eutrophicated river and sustainable water resource management. At present, most of the existing studies are static or closed water box tests, with few river field experiments. The only field tests were also just confined to purification function. There has been very little information published to date about FTW plant management in the river. The aim of this paper is to seek effective and reasonable methods for FTW management, which can provide scientific foundation for the application of this technology.Ipomoea aquatica was used as FTW plant in both field experimentation and controled experimentation to evaluate the effects of different cutting frequency and stubble heights. With field experimentation, we assessed the effects of different cutting regimes on the output of floating plants by analyzing sprout, biomass, stem-leaf ratio; while with controlled experimentation, we evaluated the effects of cutting regimes on water purification function, by measuring TN、NF4+、-N、TP、CODcr in the water. The main research results of this study are as follows:The effects of cutting on plant productivity(1) After cutting the plants could grow healthily during its whole lifecycle. The number of tillers was 5 times that of the initial value, with the longest roots of 27 cm, average roots length of 15 cm, and average root system diameter of 11 cm. The fresh root biomass of single plant was 146 g, which could adsorb 3.36 kg suspended particulates per square meter of floating mat.(2) Sprout growth rate went gradually up and then down with the increase of cutting times, at the range of 0.54-3.7 cm·d-1 in different cutting treatments, compared with 1.63 cm·d-1 of no-cutting. Only appropriate cutting could promote sprout growth rate.The change of biomass harvested resembles that of sprouts, and the average biomass growth rate was between 3.83-37.9 g·m-2·d-1.(3) Concerning total biomass, the treatment of cutting every 4 weeks, and stubble heights at 25 cm or 35 cm could obtain maximum biomass, at 2112 g·m-2; Concerning stem-leaf ratio, the treatments of cutting every 2 weeks and every 3 weeks with stubble heights at 15 cm or 25 cm were better than other treatments; Concerning both biomass and quality, as well as management convenience, cutting every 3 weeks with stubble heights at 15 cm was the best. Under this cutting regime, sprout growth rate was 1.88 cm·d-1, stem-leaf ratio was less than 1, and the total biomass was 1966 g·m-2.The effect of floating treatment wetland system on water purification(1) The concentration of TN reduced with the time passing. Concerning cutting frequencies and stubble heights, the effects of FTW on TN removal were found to be significantly different (P<0.05) among different treatments. The removal rate for TN from the treatment of non-harvest (78%) is much higher than that from no-floating bed system (48%). Concerning TN removal, the treatment of cutting every 3 weeks and stubble height at 16 cm or 24 cm, or cutting every 4 weeks with stubble height at 16 cm will result in good performance. The average TN removal rate is about 80% for these treatments.(2) The concentration of TP also reduced with the time passing. No significant different (P>0.05) for TP reduction was found among all the treatments. Therefore, there was no effect of cutting on TP purification. The removal rate for TN (80%) is better than that for TP (64%), taking non-harvest treatment as an example.(3) The change for the concentration of CODcr was fluctuating with the time passing. The effect of floating bed on CODcr removal is not apparent.(4) The concentration of NH4+-N also reduced with the time passing, for which the purification rate was above 95%, even close to 100% in most of the treatments, among with, no significant different effects was found.更多还原