电化学辅助微电解法处理焦化废水

制备了锰粉改进的规整化微电解填料,采用电化学辅助改进微电解填料处理初始COD为6 153.6 mg/L、ρ(NH_3-N)为182.6 mg/L的焦化废水,优化了工艺条件。实验结果表明,电化学辅助微电解法处理焦化废水的最佳工艺条件为电压8 V,填料投加量20 g/L,初始废水pH 6,反应时间30 min。在此条件下废水COD去除率为75.3%,NH_3-N去除率为65.4%;在其他工艺条件相同的情况下,未通过电化学辅助的填料微电解反应的COD去除率为33.0%,NH_3-N去除率为16.2%,电化学辅助后的COD去除率和NH_3-N去除率均明显提高。     

粉末活性炭的Fenton氧化再生

采用Fenton氧化法对吸附处理染料废水后的饱和粉末活性炭(饱和炭)进行再生,考察了饱和炭的再生效果及其主要影响因素。实验结果表明:饱和炭的最佳再生条件为H2O2投加量6.5 mmol/g、再生p H 3.0、H2O2与Fe2+的摩尔比10、再生时间1 h;最佳条件下的再生率(再生粉末活性炭(再生炭)与新粉末活性炭对废水COD去除率的百分比)约为60%;使用最佳再生条件下得到的再生炭对废水进行吸附处理,废水的COD去除率和脱色率分别约为27%和67%。     

The velocity of DNAPL fingering in water-saturated porous media: laboratory experiments and a mobile–immobile–zone model

Dense nonaqueous phase liquids (DNAPLs) are immiscible with water and can give rise to highly fingered fluid distributions when infiltrating through water-saturated porous media. In this paper, a conceptual mobile–immobile–zone (MIZ) model is presented to describe the structure of a DNAPL finger in water-saturated porous media and the velocity of finger propagation. A finger is composed of a finger body and a tip. The finger body has a mobile core and an immobile sheath. All the DNAPL within the tip of a finger is mobile. Lab experiments utilizing image analyses of a DNAPL (PCE) penetrating into water-saturated homogeneous glass beads were carried out in a two-dimensional transparent chamber. The results show that the fingers elongated almost linearly with time. The fingers did not grow laterally after the tip of the finger had passed. The average finger diameters were between 3.9 and 5.4 mm for PCE propagation in water-saturated glass bead porous media with mean particle diameters from 0.32 to 1.36 mm. The estimated mobile core diameters were 51–60% of the average finger diameters.     

Distribution of gelatinous macrozooplankton in the southern Black Sea during 1996–1999

In this study, spatial and temporal distributions of three gelatinous macrozooplankton, the scyphozoan Aurelia aurita and the ctenophores Pleurobrachia pileus and Mnemiopsis leidyi, were evaluated using the data obtained from seven southern Black Sea cruises carried out from 1996 to 1999. A comparison of nets used for the sampling of gelatinous macrozooplankton illustrated the superiority of the Hensen net with a larger mesh size (300 µm) over the Nansen net (112 µm). P. pileus was mainly concentrated below the mixed layer, while A. aurita and M. leidyi were generally confined to surface waters. Horizontally, P. pileus was associated with deep, offshore waters. P. pileus also displayed the least interannual variation of the three species. Biomass of A. aurita and M. leidyi varied substantially seasonally and inter-annually. In September 1999, the average biomass of M. leidyi was at its lowest level (12 g wet weight m^-2) since its explosive development at the end of the 1980s. This was associated with the appearance of the new predatory ctenophore Beroe ovata, which appeared in the Black Sea at the end of the 1990s.     

Emergy evaluation and economic analysis of three wetland fish farming systems in Nansi Lake area,China

Emergy and economic methods were used to evaluate and compare three fish production models, i.e., cage fish farming system, pond intensive fish rearing system and semi-natural extensive pond fish rearing system, in Nansi Lake area in China in the year 2007. The goal of this study was to understand the benefits and driving forces of selected fish production models from ecological and economic points of view. The study considered input structure, production efficiency, environmental impacts, economic viability and sustainability. Results show that the main difference among the three production systems was the emergy cost for fish feed associated with their feeding system, i.e., feeding on natural biomass such as plankton and grass or on commercial feedstock. As indicated by EYR, ELR and ESI, it can be clearly shown that the intensive production model with commercial feed is not a sustainable pattern. However, the point is that more environmentally sound patterns do not seem able to provide a competitive net profit in the short run. The intensive pond fish farming system had a net profit of 2.57E+03 $/ha, much higher than 1.27E+03 $/ha for cage fish farming system and slightly higher than 2.37E+03 $/ha for semi-natural fish farming system. With regard to the drivers of local farmer’s decisions, the accessibility of land for the required use and investment ability determine the farmer’s choice of the production model and the scale of operation, while other factors seem to have little effect. Theoretically, the development of environmentally sustainable production patterns, namely water and land conservation measures, greener feed as well as low waste systems is urgently needed, to keep production activities within the carrying capacity of ecosystems. Coupled emergy and economic analyses can provide better insight into the environmental and economic benefits of fish production systems and help solve the problems encountered during policy making.     

The metabolic fate of 14C‐parathion by some fresh water phytoplankton and its possible effects on the algal metabolism

Abstract

The growth and total carbohydrate contents of Nostoc muscorum and Tolypothrix tenuis were greatly and significantly reduced by the application of parathion. “Chlorophyll a”, carotene biosynthesis and the rate of glucose absorption were enhanced after supplementation of parathion to the culture media of both cyanobacteria. Nitrogen released to the media, total nitrogen content and total nitrogen fixed were increased in both organisms‐ Increase in protein content was accompanied by remarkable drop in amino, peptide and ammonia fractions‐ Phosphorus uptake, RNA, DNA and total phosphorus content were accelerated to reach maximum accumulation at the highest insecticide level. In metabolism study using ¹⁴C‐labelled compound, parathion was readily degraded by Nostoc and Tolypothrix. Following ten days incubation, the aqueous fractions contained 21.1% and 18.1% of the initial activity in Nostoc and Tolypothrix respectively. TLC analysis of the hydrolytic products revealed the presence of three metabolites: p‐aminophenol, p‐nitrophenol and aminoparathion.     

Similarity of food spectra,habitat types,and ranges of artiodactyls in the Far East

The ranges, spectra of habitat types, and food spectra of artiodactyls in the Far East have been studied. It has been supposed that the overlap of ranges and habitat-type spectra should decrease with an increase in the overlap of food spectra. However, all the three similarity indices have proved to be positively correlated with each other, suggesting that, on the regional scale, the negative role of trophic competition in artiodactyl communities is insignificant, probably because of their low abundance. Conversely, the similarity of food spectra may be regarded as a factor accounting for the overlap of ranges and habitat spectra and, on a large-region scale, for the maintenance of high species diversity.     

深井冰冷冻系统

深井降温是深部矿产资源开采过程中的主要技术问题之一 ,讨论一种深井降温的新技术及方法冰冷冻系统     

Treatment of municipal wastewater using a contact oxidation filtration separation integrated bioreactor

A new contact oxidation filtration separation integrated bioreactor (CFBR) was used to treat municipal wastewater. The CFBR was made up of a biofilm reactor (the upper part of the CFBR) and a gravitational filtration bed (the lower part of the CFBR). Polyacrylonitrile balls (50 mm diameter, 237 m²/m³ specific surface, 90% porosity, and 50.2% packing rate) were filled into the biofilm reactor as biofilm attaching materials and anthracite coal (particle size 1–2 mm, packing density 0.947 g/cm³, non-uniform coefficient (K₈₀ = d₈₀/d₁₀) < 2.0) was placed into the gravitational filtration bed as filter media. At an organic volumetric loading rate of 2.4 kg COD/(m³ d) and an initial filtration velocity of 5 m/h in the CFBR, the average removal efficiencies of COD, ammonia nitrogen, total nitrogen and turbidity were 90.6%, 81.4%, 64.6% and 96.7% respectively, but the treatment process seemed not to be effective in phosphorus removal. The average removal efficiency of total phosphorus was 60.1%. Additionally, the power consumption of the CFBR was less than 0.15 kWh/m³ of wastewater treated, and less than 1.5 kWh/kg BOD₅ removal.     

Modeling the fate and transport of non-volatile organic chemicals in the agro-ecosystem: A case study of Cameron Highlands,Malaysia

Many pesticides used in agricultural activities are considered environmentally non-volatile. The main purpose of this paper is to develop multimedia model to be used as a tool to predict the overall fate and transport of non-volatile organic chemicals (NVOCs) dynamic in the agro-ecosystem. The model was developed based on the EQuilibrium Criterion (EQC) model for type 2 chemicals introduced by Mackay and colleagues in 1996. Mackay’s model only considered four environmental compartments, which are air, water, soil and sediment. The present model adds the vegetation compartment, in addition to previous compartments that shape the agro-ecosystem. The vegetation compartment is described by two sub-compartments consisting of the above ground plant (AGP) and roots. The model was parameterized for the Cameron Highlands region, Malaysia, and runs with an illustrative emission rate of 1 kg h^?1 into the air for three selected pesticides, namely, mancozeb, spinosad and chlorosulfuron. The simulation results with and without vegetation compartment were compared. The estimated results indicating that the AGP captures 99.9% of introduced NVOCs (i.e., of 100% or 1 kg h^?1) and transfers them to the ground below due to the slight degradation losses of 10^?4% and the non-volatility property of the evaluated chemicals. Root uptake of chlorosulfuron accounted the highest removal process from soil while degradation of spinosad in the soil is the major loss mechanism. Leaching to groundwater loss for mancozeb is about 2-fold greater than that of degradation, which together accounted the major removal process from soil. Based on the estimated results of mass distribution on the overall system, vegetation compartment accumulates 0.04%, 0.5% and 2.02% of the mancozeb, spinosad and chlorosulfuron, respectively.