Connecting sources, fractions and algal availability of sediment phosphorus in shallow lakes: An approach to the criteria for sediment phosphorus concentrations

Although point and nonpoint sources contribute roughly equal nutrient loads to lakes, their relative role in supporting algae growth has not been clarified. In this research, we have established a quantitative relationship between algae-available phosphorus (P) and P chemical fractions in sediments; the latter indicates the relative contribution of point versus nonpoint sources. Surface sediments from three large shallow lakes in eastern China, namely, the Chaohu, Taihu and Hongzehu Lakes, were sampled to assess their algae-available P and chemically extracted P fractions. The algae-available P primarily comes from iron/aluminium (hydr)oxide-bound P (Fe/Al-bound P), 45% of which is algae-available P. The ratio of Fe/Al-bound P to calcium compound-bound P (Ca-bound P) indicated the relative contribution of point to nonpoint sources, with the point sources contributing the majority of increased Fe/Al-bound P in sediments. Therefore, the reduction of point sources from urbanized areas, rather than nonpoint sources from agricultural areas that primarily contribute to the Ca-bound P fraction, should be prioritized to alleviate cyanobacterial algal blooms (CyanoHABs) in shallow lakes with sediment P as a potential source to support algae growth. With these important results, we proposed a conceptual model for “P-pumping suction” from sediments to algae to aid in the development of the criteria for sediment P concentrations in shallow lakes.     

Total nitrogen and community turnover determine phosphorus use efficiency of phytoplankton along nutrient gradients in plateau lakes

Numerous studies support that biodiversity predict most to ecosystem functioning, but whether other factors display a more significant direct impact on ecosystem functioning than biodiversity remains to be studied. We investigated 398 samples of the phytoplankton phosphorus resource use efficiency (RUE_P = chlorophyll-a concentration/dissolved phosphate) across two seasons in nine plateau lakes in Yunnan Province, China. We identified the main contributors to phytoplankton RUE_P and analyzed their potential influences on RUE_P at different lake trophic states. The results showed that total nitrogen (TN) contributed the most to RUE_P among the nine lakes, whereas community turnover (measured as community dissimilarity) explained the most to RUE_P variation across the two seasons. Moreover, TN also influenced RUE_P by affecting biodiversity. Species richness (SR), functional attribute diversity (FAD2), and dendrogram-based functional diversity (FDc) were positively correlated with RUE_P in both seasons, while evenness was negatively correlated with RUE_P at the end of the rainy season. We also found that the effects of biodiversity and turnover on RUE_P depended on the lake trophic states. SR and FAD2 were positively correlated with RUE_P in all three trophic states. Evenness showed a negative correlation with RUE_P at the eutrophic and oligotrophic levels, but a positive correlation at the mesotrophic level. Turnover had a negative influence on RUE_P at the eutrophic level, but a positive influence at the mesotrophic and oligotrophic levels. Overall, our results suggested that multiple factors and nutrient states need to be considered when the ecosystem functioning predictors and the biodiversity-ecosystem functioning relationships are investigated.     

模拟降雨条件下沉积物对磷的富集机理

通过模拟降雨径流实验，在７２ｍｍ／ｈ的大暴雨备件下，研究侵蚀性颗粒从土壤中的径流流失过程及其对磷的富集作用和机理。结果表明，深积物中不同粒长团聚体的组成和原来土壤中的组成有很大差异。径流流失的沉积物主要以０．２５ｍｍ以下的团聚体为主，径流中８０％以上的磷以颗粒态形式流失，而颗粒态磷的６０％－９０％随０．１ｍｍ以下的团聚体流失。不同粒径团聚体对磷的富集作用和富集系数不同。模拟实验建立了沉积物富集系数     

基塘水产养殖对水域氮磷的影响

基塘系统是一种相对封闭的人工生态系统，其鱼塘子系统中的营养盐－氮、磷既是鱼类生长的必需元素，又是水体中的限制性元素。氮、磷的变化受塘中水生生物活动（如光合作用、呼吸、排泄）、鱼类粪便、饲料投加、底泥等的影响，文中对基塘中氮磷的变化及影响因子进行探讨。     

总氮、总磷联合测定方法的改进

采用钼锑分光光度法测定总氮,考察了在提高温度的条件下,缩短消解时间对测定结果的影响。试验结果表明,调节氢氧化钠和过硫酸钾的用量,在同一溶液内测定总氮、总磷,并且将测定条件改为126～128℃,消解10min,其测定结果和与标准方法对照,精密度及准确度均令人满意。     

污水处理厂污泥中磷的回收

磷是一种不可再生而又面临枯竭的重要资源。为控制水体富营养化,污水处理厂采用生物除磷脱氮工艺把污水中的磷转移到污泥中以除去;由此形成富磷污泥,为实现污泥磷回收创造了条件。并介绍了三种从污水处理厂剩余污泥中回收磷的工艺:污泥水解回收磷的工艺(KREPROProcess和Cambi-KREPROProcess)和从污泥焚烧灰中回收磷的工艺(BioConProcess)。这些工艺可以以磷酸铁或磷酸的形式回收污泥中约75%的磷。     

胰岛素废水处理工程设计

针对某医药公司在制取胰岛素过程中产生的高浓度废水，采用预处理（酒精回收-盐水投配-除油）-倒A2O-接触氧化-化学除磷组合工艺进行调试，其处理效果明显，出水各项指标均能达标，同时对工艺中存在的缺陷进行了分析。     

EM菌强化SBR脱氮除磷的试验研究

重点讨论了有效微生物群（EM）在SBR反应器中对生活污水的TP，NH3－N和TN和TN的去除效昆，结果表明，当EM投加量（VEM／V污水）为1／1000－1／1000时，能显著提高SBR工艺对TP，NH3－N和TN的去除率和降解速度，具有节能降耗的优点，当EM投加量（VEM／V污水）在1／1000－5／1000范围内，TN的去除率随EM量的增加而逐渐提高。     

现行收费政策与污染物排放总量控制政策探讨

着重讨论了现行收费政策中存在的一些亟待解决的问题，提出改革现行收费政策的几个原则，探讨了按污染物排放总量收费应执行的原则和收费标准     

实施总量控制与环境技术市场发展

实施总量控制为环境技术市场的发展创造了条件，对环保产业提出了更高的要求，也将推动环境技术市场竞争正常化。