Nitrogen (N) and phosphorus (P) released from the sediment to the surface water is a major source of water quality impairment. Therefore, inhibiting sediment nutrient release seems necessary. In this study, red soil (RS) was employed to control the nutrients released from a black-odorous river sediment under flow conditions. The N and P that were released were effectively controlled by RS capping. Continuous-flow incubations showed that the reduction efficiencies of total N (TN), ammonium (NH4+-N), total P (TP) and soluble reactive P (SRP) of the overlying water by RS capping were 77%, 63%, 77% and 92%, respectively, and nitrification and denitrification occurred concurrently in the RS system. An increase in the water velocity coincided with a decrease in the nutrient release rate as a result of intensive water aeration.
The construction of an ecocity is gradually gaining attention as an indicator of sustainable development. Genuine saving rate (GSR), which takes account of various impacts of economic activities including depletion of natural resources, costs of environmental pollution and long-term environmental damage, can be used as an integrated indicator to measure the status quo and potential of sustainability for an ecocity. This paper discusses the concept of an ecocity; and analyses the time-series of GSR in Suzhou between 1991–2001 as a case study used to develop a standard method of measuring sustainability. The status quo and trends in urban sustainability in six case study cities in China are then evaluated and compared. The results show the current status: Suzhou (23.6%), Guangzhou(18.9%), Ningbo (14.7%), Yantai (13.1%), Yangzhou (11.7%) and Sanming (7.9%). The study demonstrates that GSR provides not only a linkage by which local governmental departments for resources management, environmental protection, finance and planning can be connected directly, but also an effective analytical tool for the planning and construction of an ecocity as well as decision-making support for local governments. 相似文献
An interval dynamic multimedia fugacity (IDMF) model with a new validation criterion of interval average logarithmic residual error (IALRE) was developed in this study. The environmental fate of polycyclic aromatic hydrocarbons (PAHs) and their source apportionment in a typical oilfield of China were simulated from 1985 to 2010. The PAH concentrations predicted by the model were in agreement with the measured concentrations, which were indicated by the IALREs calculated at 0.41, 0.63, 0.52, and 0.58 for air, water, soil, and sediment, respectively. The multimedia concentrations of Σ16 PAHs were 29.55, 39.22, 31.98, and 26.69 times greater in 2010 than those in 1985, and were higher than any other year modelled. Additionally, 87.82% of PAHs remained in the soil in 2010. PAH source emission into the soil was the major modelled source, whereas PAH degradation in the air was the major modelled loss pathway; the dominant transfer process between the adjacent compartments was atmospheric deposition from air to soil. It was demonstrated that high-temperature combustion was the major source of PAHs in the air and soil, whereas biomass and coal combustion were attributed to water and sediment compartments. The IDMF model was effective in the dynamic source apportionment of PAHs. 相似文献
The analytical results of 53 manure samples determined by wet digestion and dry ashing procedures were compared in order to evaluate their relative suitability for recovering different nutrient elements in manure and manure compost. Wet digestion recovered greater amounts of phosphorus (P), potassium (K), calcium (Ca), manganese (Mn), and zinc (Zn) in more samples than dry ashing. Nutrient contents in the samples were highly variable, with coefficients of variation (CV) ranging from 38% for magnesium (Mg) to 161% for copper (Cu) analyzed by the wet digestion procedure, and from 47% to 138% for Mg and Cu analyzed by the dry ashing procedure. The mean values of P, K, Ca, Mn, and Zn averaged for the 53 samples were significantly higher using wet digestion than dry ashing procedure, but both procedures recovered comparable amounts of iorn (Fe), Mg, and Cu. Correlations analysis between both procedures for each element showed reasonable to fair agreements for Ca (R2?=?0.93), K (R2?=?0.93), P (R2?=?0.90), Mg (R2?=?0.84), Fe (R2?=?0.87), Mn (R2?=?0.73), and Cu (R2?=?0.66), but poor agreement for Zn (R2?=?0.44). The low agreement between procedures for Zn suggests that wet digestion, which gave a higher recovery, should be a preferred procedure for analyzing Zn in manures. 相似文献