普通小球藻对养殖污水脱氮除磷的效果研究

随着我国养殖业的不断发展,养殖污水排放量的日益增加,养殖污水的高氮、磷含量导致水体富营养化问题日趋严重。小球藻是光能自养生物,能有效同化氮、磷,使污水中的氮、磷减少。本研究通过在实验室模拟不同氮、磷含量的养殖污水环境,分析小球藻对氮、磷的去除效果;在此基础上,用小球藻处理某养殖场污水;并联合膨润土与小球藻,探究两者脱氮除磷的协同作用能力及膨润土对小球藻细胞沉降的效果。结果表明,小球藻对模拟污水的氨氮去除率可达80%,对磷酸根的最高去除率接近100%;对养殖污水中的氮、磷也有一定的去除效果;但养殖污水成分复杂,小球藻的生长被抑制。膨润土与小球藻的结合,能够提高污水中的氮磷去除率并帮助藻细胞快速沉降,为污水处理后藻细胞的收集处理提供了有效方法。     

汉沽污水库养鱼试验研究

本研究表明:汉沽污水库进水口污水对鱼类毒性很大,它对白鲢、鲤鱼和鲫鱼24小时半数致死浓度分别为3％、30％和58％(V/V)。汉沾污水库对化工废水有一定自净能力,净化后的水质是有益于鲫鱼生存、发育和繁殖的。污水库中的鲫鱼对DDT积累不明显;对666虽有积累但不超过食用标准(2ppm);对汞的积累量较高,100天内鲫鱼肌肉汞含量超过食用标准(0.3ppm)26倍。鲫鱼对汞、DDT、666均有排除能力,其排除速率的快慢顺序为:666>DDT>Hg。     

水体富营养化过程中氧含量变化问题探讨

随着经济的进一步发展 ,大量含氧、磷肥料的生产和使用、食品加工、畜产品加工等造成的工业废水和大量城市生活废水 ,特别是含磷洗涤剂产生的污水未经处理即行排放 ,使海水、湖水中富含氮、磷等植物营养物质 ,称为水体富营养化。在富营养化的水体中 ,由于有了充足的养料保证 ,藻类等浮游植物一有适宜条件即大量繁殖。此时鱼类等生物的消费能力 (以藻类为食 )赶不上藻类的繁殖速度 ,水中藻类越长越多 ,它使水中氮含量减少 ,导致水中的鱼类等生物大量死亡。在教学过程中 ,发现有许多学生错误认为藻类疯长 ,应该是光合作用增强 ,产生氧气量增多…     

氮磷对污水净化中藻类群落结构的影响

在室内模拟生物净化槽中比较研究了氮,磷对污水净化藻类群落结构和污水净化效果的影响。其结果ＴＮ／ＴＰ＝４４．７／７．０１ｍｇ／Ｌ组,藻类种类多样性最高,净生产力最高,污水净化效果也最佳。     

贵州百花湖鱼体汞污染现状

以西南汞污染严重的贵州百花湖为对象,选取湖中优势鱼、贝类,通过测定其总汞和甲基汞含量,并结合水体、沉积物汞含量和相关水质参数,探讨了百花湖鱼类汞污染的现状及其影响因素.百花湖鱼体总汞平均含量为28.0ng·g-1,变化范围为4.2～143ng·g-1;甲基汞的平均含量为10.9ng·g-1,变化范围为3.0～39.3ng·g-1.虽然百花湖遭受上游贵州有机化工厂含汞废水的严重污染,但鱼体汞含量并没有超过国家食品卫生标准.其主要原因可能是:百花湖的鱼主要是人工养殖的草食性或杂食性鱼类,鱼龄较小,且其摄取的食物汞含量低、食物链简单,不利于汞的富集;其次,其较快的生长速度对鱼体汞具有生物稀释的作用.     

水环境质量的常见指示鱼类

鱼类与人类有着密切的关系,它们不仅为人类提供丰富的营养食品、科研材料、生物药,还是维持水环境生态平衡、调节水质公认的重要生物类群,人们称它们为水环境的“清洁员”。其中,有的种是水质量的指示鱼类,有的种是污水的净化种或养殖种类,它们在水环境中的作用,越来越受到人们的重视。     

利用北京城市生活污水饲养鲢鱼的观察

城市人口密集,每天有大量污水排出。如能利用下水道排出的生活污水作为水源和肥料培养鱼池中的饵料生物,以供给养殖鱼类的需要,不但可以节约大量饲料和肥料,而且可使污水得到净化,有利城市卫生。因此,发展城市生活污水的养鱼是城郊养鱼的良好途径。     

养殖污水直灌对稻田土壤氮、磷积累与垂直迁移的影响

尽管国内外对养殖污水处理已提出了一系列的工艺技术,但因经济原因养殖污水直接灌溉农田在我国农村地区仍较为常见.为了解长期畜禽养殖污水直灌对稻田土壤质量的影响,在浙江省绍兴市柯桥区选择了养殖污水直灌不同年限(0、4、7、13年)的稻田,比较研究了养殖污水直接灌溉对稻田土壤不同深度土层中各形态氮和磷含量的影响,探讨了长期养殖污水灌溉对氮、磷在土壤剖面中垂直迁移的影响.结果表明: 长期养殖污水直接灌溉可显著提高稻田土壤中氮和磷的积累,积累量随灌溉年限的增长而增加,其中磷素的增幅高于氮素.养殖污水灌溉4、7和13年后,土壤表层中全P和全N分别比对照增加了43.6%、95.2%、1484%和7.7%、17.0%、28.4%.土壤氮素的变化为NH₄⁺-N、NO₃^--N>酸解有机氮>非酸解有机氮;土壤有效磷的变化明显大于全磷.长期养殖污水灌溉可促进氮、磷在土壤剖面中的垂直迁移,增加对地下水的污染风险.
     

基于微藻培养处理畜禽养殖废水的研究进展

当前规模化畜禽养殖业排放含有大量氮磷、重金属和有机污染物的粪污废水,导致生态环境遭受严重的污染,治理畜禽废水的任务迫在眉睫。由于传统畜禽废水处理方式及应用存在较多不足,基于微藻生物技术处理废水的研究得到越来越多的关注。微藻是一种广泛存在于水体中的单细胞生物,具有高效的脱氮除磷及纳污能力,其主要利用同化作用吸附污水中的氮,通过磷酸化作用吸附、沉降磷,依靠细胞膜上的官能团对重金属进行富集。基于以上生理基础,大多数微藻的氮磷吸附率和重金属富集率可以高达80%。目前微藻对畜禽废水污染组分的处理的研究主要集中在氮磷、重金属,实际应用方式多为高效藻类塘、活性藻、固定化技术、光生物反应器等。但是微藻处理畜禽废水仍存在分子机理研究较少,生产实际经验不足等问题。基于微藻处理畜禽废水的机理,通过综述若干微藻去除氮磷、重金属等污染物的效率,总结国内外微藻废水处理技术的研究及存在问题,展望了微藻废水工程发展前景。     

利用丝状绿藻处理含汞污水的试验

用刚毛藻科的丝状绿藻为材料,进行了藻类处理含汞(HgCl_2)污水的试验。Hg~( )浓度为0.5,1.0,2.0,5.0和10.0毫克/升,鲜藻与污水的重量之比为1∶100,4小时内,汞的去除率为70%。进行了藻类连续去汞能力的测定,10克鲜藻依次放入4个含汞污水的水样中(水量均为1升,Hg~( )浓度平均为3.61毫克/升),在每个水样停留时间为6小时,结果汞的去除率分别为76.8,78.4,61.8,53.1%,平均为67.5%,藻类含汞浓度以鲜重计算达到970ppm。利用藻类四级串联处理含汞量为4.0毫克/升的污水,停留时间共计24小时,总去除率达94%。从试验结果看来,藻类对汞的去除,主要是借助于表面吸附与细胞积累作用,与藻类的光合作用无关。但是0.1—10毫克/升的汞,都明显地抑制藻类的光合放氧,这种抑制作用在藻类接触汞4小时以后表现出来。     

死鱼事件中污染源废水对鱼类急性毒性及诱变微核的研究

为了研究2006年9月广州郊区某鱼塘因化工企业污染源废水进入而导致大量死鱼事件中鱼类死亡原因,用斑马鱼（Brachydanio rerio）和蚕豆（Vicia faba）根尖对污染源废水及鱼塘水分别进行了鱼类急性毒性试验和蚕豆根尖微核试验.污染源废水和鱼塘水的96hLC50分别为1.69%、23.95%,污染源废水和鱼塘水的微核率分别为27.8‰、13.7‰,污染源废水和鱼塘水的COD、BOD、石油类、氨氮、总磷等均出现超标情况,其中氨氮、苯胺、石油类污染物严重超标.监测结果表明,以氨氮污染为主的污染源废水是导致死鱼事件的主要原因,废水对蚕豆根尖微核率的形成具有显著性影响,可能存在潜在的致突变性危险.     

Assessing the Risk of Hydroxybenzene Contamination in Fish Raised on a Chinese Aquaculture Farm

We estimated the risk posed by hydroxybenzene in farm-raised Crucian carps (Carassius carassius) from a pond on a fish farm in Beijing, China, by analyzing a time-series of observed hydroxybenzene concentrations in fish within a culturing season in year 2006. We used the basic linear regression to model the data and forecast the probability of hydroxybenzene concentration in pond fish exceeding selected health effect criteria (the risk) using Monte Carlo simulation. The risk is highly correlated with the time a fish stays in the pond. The results indicate that the risk–days in pond relationship resembles a sigmoid function with an inflection point around 150 days. The resulting model can be used to demonstrate the benefit of improving water quality in terms of increased fish production.     

Mangroves as filters of shrimp pond effluent: predictions and biogeochemical research needs

Preliminary estimates of the ratio of mangrove forest: shrimp pond area necessary to remove nutrients from shrimp pond effluent are made using budgets of nitrogen and phosphorus output for semi-intensive and intensive shrimp ponds combined with estimates of total net primary production in Rhizophora-dominated mangrove forests in tropical coastal areas. If effluent is delivered directly to mangrove forest plots, it is estimated that, depending on shrimp pond management, between 2 and 22 hectares of forest are required to filter the nitrogen and phosphorus loads from effluent produced by a 1 hectare pond. While such ratios may apply to small scale, integrated shrimp aquaculture — mangrove forestry farming systems, the variability in mangrove hydrodynamics makes it difficult to apply such ratios at a regional scale. Before mangroves can be used to strip shrimp pond effluent more research is required on the effects that high ammonia and particulate organic matter loads in pond effluent have on nutrient transformations in mangrove sediments and on forest growth.     

A thermal effluent as a sporadic cornucopia: effects on fish and zooplankton

Synopsis We report effects of a thermal effluent on fish and zooplankton in an impoundment in South Carolina. The effects are not directly due to heated effluent but are indirect effects on the trophic dynamics of the system and depend on the physical structure of the system, season, and geography. As effluent from a nuclear reactor cooling pond (Pond C) enters the larger Par Pond it sporadically carries with it zooplankton and/or dead fish. Pond C produces high zooplankton densities in two situations: (1) high and hot effluent flow during cold winter weather; and (2) low (cool) effluent flow during warmer seasons. High zooplankton densities attract Blueback herring, Alosa aestivalis, which attract largemouth bass, Micropterus salmoides. Dying and dead bluegills, Lepomis macrochirus from Pond C (heat killed) are eaten by Par Pond bass which swim into effluent temperatures as high as 46°C to take these easy prey. Blueback herring and largemouth bass distribution are affected by the presence of food rather than by temperature. Par Pond blueback herring appear to be available to bass mainly when herring are near the effluent from Pond C and when they spawn in spring in the littoral zone. Because Blueback herring in Par Pond live only one year and because their presence in bass habitat is seasonal there is a strong seasonal component to bass food abundance. A previously reported annual oscillation in bass condition (K), with a peak in winter, occurs throughout Par Pond but is extreme in the vicinity of the effluent. The strong seasonality of food abundance for bass at the effluent correlates the winter peak in bass condition.     

Influence of the fish pond aquaculture effluent discharge on abiotic environmental factors of selected rivers in Northwest Poland

Pollution of rivers caused by human activity is a widely discussed problem, however there is not much attention paid to the changes of water quality that result from the inflow of effluent discharged from fish breeding ponds. The paper presents results of studies on changes of the abiotic parameters (hydrochemical and hydrological) of water observed in the yearly cycle between 2004 and 2008 in selected rivers of Northwest Poland. It was proved that the fastest reaction on the inflow of the effluent discharged from the fish ponds was reflected in changes of biogenic and organic compounds in the river water. The largest, i.e. threefold (rivers Krapiel and Tywa) or even fourfold (rivers Rurzyca and Stepnica) increase in nutrients and organic matter was recorded during the pond effluent discharge into the rivers. At that time values of the organic matter ranged from 8.9 to 18.3 mgO₂/dm³ (BOD₅), the nitrogen compounds from 16.868 to 26.930 mgN/dm³, while the phosphorus from 1.928 to 6.353 mgP/dm³. Interestingly, an additional dry mass of seston was recorded no earlier than the activity of the harmful element had been stopped and the river had resumed to the “initial” state (i.e. before the effluent discharge); that period varied from one to two months, depending on the river characteristics. The highest values of the dry seston mass (580.9 mg/dm³) was recorded in river Krapiel in November 2006. It seems that in spite of remarkable influence on values of individual physical and chemical indices of the river water quality, the effluent discharge from the fish ponds is not a factor hampering the self-purification processes of the rivers.     

Benthic freshwater nematode community dynamics under conditions of Tilapia aquaculture in Egypt

Studies of the influence of fish aquaculture on benthic freshwater nematode assemblages are scarce, but could provide a way of gauging environmental effects. The abundance and diversity of nematode assemblages in response to Oreochromis niloticus aquaculture were investigated in Kafr El-Sheikh Governorate, Egypt, from July to November 2014 under conditions of irrigation (reference), fish farm pond with high Tilapia density, and fish farm pond effluent canal without fish. The nematode genera Adoncholaimus, Punctodora, Labronema, Oncholaimus and Odontolaimus were present at all sites. Environmental factors were not related to nematode distribution patterns. Tilapia predation and/or disturbance may explain reduced nematode abundance, especially of the largest genera, Adoncholaimus, Punctodora and Labronema at the fish farm site. The absence of fish from the drainage site allowed intergeneric nematode competitive exclusion, benefitting the largest nematodes and reducing diversity indices.     

几种氯苯对模拟氧化塘系统生物群落的影响

研究一氯苯,１,２,３－三氯苯及六氯苯对模拟氧化塘系统生物群落结构的影响及其净化机制。结果表明,在５．６０９５ｍｇ／ｌ的一氯苯,１．９２９２ｍｇ／ｌ的１,２,３－三氯苯及０．１３６３ｍｇ／ｌ的六氯苯实验条件下,系统中杆菌属、微球菌属及酵母菌属的种类、密度影响不明显;对浮游藻类的种、数量及叶绿素ａ的合成有明显地抑制作用,其影响大小的顺序为：六氯苯〉１,２,３－三氯苯〉一氯苯。在模拟氧化塘系统中,氯苯     

Lime enhanced chromium removal in advanced integrated wastewater pond system

The removal of trivalent chromium from a combined tannery effluent in horizontal settling tanks and subsequent Advanced Integrated Wastewater Pond System (AIWPS) reactors was investigated. The raw combined effluent from Modjo tannery had pH in the range of 11.2-12. At this pH, a trivalent chromium removal of 46-72% was obtained in the horizontal settling tanks after a one-day detention time. Trivalent chromium precipitated as chromium hydroxide, Cr(OH)3. 58-95% Cr(III) was removed in the advanced facultative pond (AFP) where the water column pH of 7.2-8.4 was close to pH 8, which is the optimum precipitation pH for trivalent chromium. Chromium removals in the secondary facultative pond (SFP) and maturation pond (MP) were 30-50% and 6-16%, respectively. With Cr(III) concentration of 0.2-0.8 mg/l in the final treated effluent, the AIWPS preceded by horizontal settling tanks produced effluent that could easily meet most of the current Cr(III) discharge limits to receive water bodies.     

Cadmium tolerance and antibiotic resistance in Escherichia coli isolated from waste stabilization ponds

The incidence pattern of cadmium tolerance and antibiotics resistance by Escherichia coli was examined periodically from the samples of water, sludge and intestine of fish raised in waste stabilization ponds in a sewage treatment plant. Samples of water and sludge were collected from all the selected ponds and were monitored for total counts of fecal coliform (FC), total coliform (TC) and the population of Escherichia coli, which was also obtained from the intestine of fishes. Total counts of both FC and TC as well as counts of E. coli were markedly reduced from the facultative pond to the last maturation pond. Tolerance limit to cadmium by E. coli tended to decline as the distance of the sewage effluent from the source increased; the effective lethal concentration of cadmium ranged from 0.1 mM in split chamber to 0.05 mM in first maturation pond. E. coli isolated from water, sludge and fish gut were sensitive to seven out of ten antibiotics tested. It appears that holistic functions mediated through the mutualistic growth of micro algae and heterotrophic bacteria in the waste stabilization ponds were responsible for the promotion of water quality and significant reduction of coliform along the sewage effluent gradient.     

Response of littoral invertebrates to reduction of fish density: simultaneous experiments in ponds with different fish assemblages

1. We experimentally reduced densities of predatory fish in replicated 2 m² areas of the littoral zone in two ponds to test whether density and biomass of invertebrates would respond to release from fish predation. The ponds are of similar size and in close proximity, but support different fish assemblages: bluegills ( Lepomis macrochirus Rafinesque) and largemouth bass ( Micropterus salmoides (Lacepede)) in one pond, and bluespotted sunfish ( Enneacanthus gloriosus (Holbrook)) and chain pickerel ( Esox niger Lesueur) in the other. Fish densities were reduced to less than 15% of ambient levels in both experiments.
2. In the bluegill–bass pond, density and biomass of most invertebrate taxa and size classes were unaffected by the fish manipulation. Total invertebrate densities did not differ significantly between fish treatments, but total invertebrate biomass was significantly greater where fish density was reduced, averaging 30% higher over the course of the study. Likewise, manipulation of fish in the bluespotted sunfish–pickerel pond had few significant effects on individual taxa and size classes. There were no significant effects on total invertebrate abundance in the bluespotted sunfish–pickerel pond.
3. Our results provide direct experimental evidence consistent with the collective evidence from previous work, suggesting that the impact of fish predation on density and biomass of invertebrate prey in littoral habitats is variable, but generally weak. Invertebrates that coexist successfully with fish in littoral systems probably are adept at taking advantage of refugia offered by the structurally complex physical environment.