Biological control experiment of excess propagation of Cyclops for drinking water security

Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. In this study, an ecological project was put forward for the excess propagation control of Cyclops by stocking the filter-feeding fishes such as silver carp and bighead carp under the condition of no extraneous nutrient feeding. The results of experiments with different stocking biomass showed that the propagation of Cyclops could be controlled effectively, and the water quality was improved simultaneously by impacting on nutriment level and plankton community structure at proper stocking density of 30 g/m^3 of water. The growth of Cyclops may not be effectually controlled with lower biomass of fish （10 g）, and the natural food chain relation may be destroyed for Cyclops dying out in water while the intense stocking of 120 g per cubic meter of water. In addition, the high predator pressure may accelerate supplemental rate of nutrients from bottom sediments to water body to add the content of total nitrogen and phosphorus in water.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Organic matter and concentrated nitrogen removal by shortcut nitrification and denitrification from mature municipal landfill leachate

An UASB＋Anoxic/Oxic （A/O） system was introduced to treat a mature landfill leachate with low carbon-to-nitrogen ratio and high ammonia concentration. To make the best use of the biodegradable COD in the leaehate, the denitrifieation of NOx^--N in the reeireulation effluent from the elarifier was carried out in the UASB. The results showed that most biodegradable organic matters were removed by the denitrifieation in the UASB. The NH4^＋-N loading rate （ALR） of A/O reactor and operational temperature was 0.28- 0.60 kg NH4^＋-N/（m^3-d） and 17-29℃ during experimental period, respectively. The short-cut nitrification with nitrite accumulation efficiency of 90%-99% was stabilized during the whole experiment. The NH4^＋-N removal efficiency varied between 90% and 100%. When ALR was less than 0.45 kg NH4^＋-N/（m^3.d）, the NH4^＋-N removal efficiency was more than 98%. With the influent NH4^＋-N of 1200-1800 mg/L, the effluent NH4^＋-N was less than 15 mg/L. The shortcut nitrification and denitrifieation can save 40% carbon source, with a highly efficient denitrifieation taking place in the UASB. When the ratio of the feed COD to feed NH4^＋-N was only 2-3, the total inorganic nitrogen （TIN） removal efficiency attained 67%-80%. Besides, the sludge samples from A/O reactor were analyzed using FISH. The FISH analysis revealed that ammonia oxidation bacteria （AOB） accounted for 4% of the total eubaeterial population, whereas nitrite oxidation bacteria （NOB） accounted only for 0.2% of the total eubaeterial population.     

Nitrogen cycling of atmosphere-plant-soil system in the typical Calamagrostis angustifolia wetland in the Sanjiang Plain, Northeast China

The nitrogen (N) distribution and cycling of atmosphere-plant-soil system in the typical meadow Calamagrostis angustifolia wetland (TMCW) and marsh meadow Calamagrostis angustifolia wetland (MMCW) in the Sanjiang plain were studied by a compartment model. The results showed that the N wet deposition amount was 0.757 gN/(m2·a), and total inorganic N (TIN) was the main body (0.640 gN/(m2·a)). The ammonia volatilization amounts of TMCW and MMCW soils in growing season were 0.635 and 0.687 gN/m2, and the denitrification gaseous lost amounts were 0.617 and 0.405 gN/m2, respectively. In plant subsystem, the N was mainly stored in root and litter. Soil organic N was the main N storage of the two plant-soil systems and the proportions of it were 93.98% and 92.16%, respectively. The calculation results of N turnovers among compartments of TMCW and MMCW showed that the uptake amounts of root were 23.02 and 28.18 gN/(m2·a) and the values of aboveground were 11.31 and 6.08 gN/(m2·a), the re-translocation amounts from aboveground to root were 5.96 and 2.70 gN/(m2·a), the translocation amounts from aboveground living body to litter were 5.35 and 3.38 gN/(m2·a), the translocation amounts from litter to soil were larger than 1.55 and 3.01 gN/(m2·a), the translocation amounts from root to soil were 14.90 and 13.17 gN/(m2·a), and the soil (0-15cm) N net mineralization amounts were 1.94 and 0.55 gN/(m2·a), respectively. The study of N balance indicated that the two plant-soil systems might be situated in the status of lacking N, and the status might induce the degradation of C. angustifolia wetland.     

丰水期鄱阳湖氮磷含量变化及来源分析

通过系统测定丰水期鄱阳湖湖水、主要支流水、长江水及部分农田水、地下水及城市污水的氮磷含量,对其氮磷含量变化及来源进行了分析,结果表明,鄱阳湖水体中主要的氮素形式是硝酸盐氮（090 mg/L）,赣江是其主要贡献者。鄱阳湖五大支流氮磷含量存在着较大的差异,赣江NO-3 N含量明显高于鄱阳湖其它主干流,而NH+4 N和TN含量以饶河的最高,TP以信江的最高。农田水、城市废水以及地下水含有较高的氮磷含量,是鄱阳湖及其五大支流氮磷的主要来源。农田水TN和TP含量最高,分别为1347、2863 mg/L。高含量的NO-3 N（735 mg/L）和NH+4 N（548 mg/L）分别出现在地下水和城市污水中。鄱阳湖水体氮负荷较大,N/P比值远大于7〖DK〗∶1。受滞留区及赣江和修水补给的影响,鄱阳湖主河道氮含量变化从上游至下游呈总体上升趋势。鄱阳湖湖体氮含量以下游最高,滞留区次之,上游主河道最低,TP含量呈相反的趋势变化。底层沉积有机物的降解和扰动导致鄱阳湖水体底层NO-3 N、NH+4 N、TN、TP的含量高于表层。     

高原浅水湖泊沉积物中磷、氮形态化学研究

以滇池马村湾和海东湾为研究对象,对其沉积物－间隙水－上覆水三界面中的磷、氮形态作研究,其中钙结合态磷占的比例最大,其次是有机/细菌聚合态磷和残渣磷;总氮含量很高,平均值为2.63 mg/g,而亚硝酸盐氮含量很低,其它三种无机氮形态（硝酸盐氮、亚硝酸盐氮和氨氮）之间并不存在恒定的化学计量关系,这主要是无机氮循环还受水体和沉积物中有机氮的影响。调查还表明沉积物中Fe P含量与间隙水中溶解性磷酸盐磷有着较好的线性关系,沉积物中Fe P含量与间隙水Eh呈对数关系。     

丹江口水库表层沉积物不同形态氮的赋存特征及其生物有效性

为了揭示丹江口水库沉积物氮空间分布特征及其生物有效性,采用连续分级提取法研究了表层沉积物中可交换态氮(Exchangeable nitrogen,EN)、酸解态氮(Acid hydrolysable nitrogen,HN)及残渣态氮(Residue nitrogen,RN)的赋存特征,同时结合生物可利用态氮的含量,探讨了各形态氮对生物可利用态氮的贡献。结果表明,丹江口水库沉积物中总氮(Total nitrogen,TN)在425~5796 mg/kg之间,平均为1 319.32 mg/kg,其中EN、HN和RN的平均值相对比例为2.15∶1.95∶1,且各形态氮含量的空间分布呈入库河流大于库区开阔区域的特征,尤其在丹江、老灌河以及犟河-堵河入库口的含量较大。潜在矿化氮(Potential mineralized nitrogen,PMN)含量在40.20~1 468.95 mg/kg之间,平均为275.06 mg/kg,其中EN对丹江口水库沉积物PMN的贡献较大,比例在19.85%~90.80%之间,平均为63.47%。各形态氮在不同的水环境条件下发生迁移转化,保持着水-沉积物界面氮的动态平衡。     

长江经济带后备适宜建设用地潜力

随着中央政府将长江经济带发展提到国家区域战略的新高度,其对建设用地的需求将进一步增加。作为客观反映地区剩余或潜在建设用地对未来人口集聚、工业化和城镇化发展承载能力的指标,后备适宜建设用地潜力成为决定研究区域能否持续稳定发展的关键因素。基于此,本文根据后备适宜建设用地的计算方法和评价技术流程,测算了长江经济带后备适宜建设用地潜力,并对其空间分布特征进行了分析。结果表明:长江经济带后备适宜建设用地面积为85 672.35 km2,约占研究区总面积的4.18%,总体潜力不大,空间上呈现出长江北部高于南部,中游、下游、上游地区依次递减的分布趋势;人均后备适宜建设用地0.22亩/人,下、中、上游地区呈现出依次递减的趋势;四川盆地、两湖平原、皖北等区域的后备适宜建设用地潜力较大,长三角、大城市市辖区以及川西地区不仅后备适宜建设用地较缺乏,人均后备适宜建设用地面积也较低。     

沸石联合微生物固定化去除微污染水体中氨氮的研究

将沸石联合经过驯化的活性污泥微生物固定化,通过静态实验.考察了不同粒径沸石及不同组分固定化方法对沸石联合微生物固定化去除氨氮的影响;通过动态实验,考察了沸石联合微生物固定化去除微污染水体中低浓度氨氮的机制.结果表明,活性污泥经过16 d的驯化,氨氮去除率为90%以上;沸石吸附氨氮为快速吸附,粒径<0.5 mm的沸石的吸附容量明显大于其他粒径的沸石;不同组分固定化小球对氨氮的去除效率不同,各组分均有贡献,吸附容量依次为:沸石固定化小球>沸石联合微生物固定化小球>微生物固定化小球;沸石联合微生物固定化去除微污染水体中低浓度氨氮可分为4个阶段,即沸石吸附阶段、吸附饱和及微生物适应阶段、硝化作用明显加强和沸石部分再生阶段、微生物作用良好和沸石进一步再生阶段,最终沸石吸附与生物再生处于良好的动态平衡中,氨氮去除率达到60%左右.     

Cu^2＋、Zn^2＋对生物脱氮系统的影响

Cu^2＋和Zn^2＋是污水处理工艺中经常遇到的金属离子。在驯化好的活性污泥系统中,研究了金属离子Cu^2＋和Zn^2＋在0～100mg／L浓度下对活性污泥生物脱氮系统的影响。试验发现Cu^2＋＞5mg／L、Zn^2＋＞30mg／L时,对硝化过程具有明显的抑制作用,在同样浓度的试验条件下cu“对硝化过程的抑制作用比Zn^2＋大。Cu^2＋≤0．5mg／L时对反硝化过程具有一定的促进作用,有助于提高TN的去除效果;Cu^2＋＞0．5mg／L时,对反硝化产生抑制作用,随着浓度的增加,TN去除率逐渐下降。Zn^2＋不影响反硝化过程,仅在大于30mg／L时,对硝化过程产生抑制作用。重金属Cu^2＋对生物脱氮系统的影响明显强于Zn^2＋。