渗滤湿地系统的工艺设计

本研究是以占地6公顷,日处理污水1400m~3的渗滤型芦苇湿地实验工程为依托,采用静态模拟与工程运转相结合的方法,着重对污水湿地处理系统BOD_5的生物降解模型进行研究,建立了确定Q值和K_T值的方法,提出了适于天津渗滤湿地系统的Q值和K_T值,为湿地系统设计提供了重要的科学依据.     

综合地震台网络办公自动化系统

计算机与网络技术高速发展的今天，办公自动化（OA）系统现已在各行各业得到广泛应用。目前市场上的办公软件产品很多且功能强大，但由于各个行业本身的特殊性，这些系统很不适合应用于地震部门。本文研究了综合地震台如何搭建适合自己的经济、简单、实用的OA系统，为国内其他地震台实现OA作一些建设性的理论及技术参考。     

人工污水中的N在模拟秋茄湿地系统中的分配循环及其净化效果

在温室中建立模拟红树林植物秋茄湿地系统，系统包括１年生秋茄苗、底泥和潮汐海水，分别用正常、５倍和１０倍浓度的人工制备的城市污水每周定时、定时对模拟系统污灌２次，持续１年。用以研究营养污物Ｎ在系统中的分配循环及被净化的效果。结果表明，加入系统中的污水Ｎ主要留存在土壤中，留存在植物中只有一小部分，４个处理污水浓度组植株中Ｎ元素周转期衣次为４．１年、４．９年、５．３年和４．３年，比２０龄的秋茄群落Ｎ周期     

长江,嘉陵江重庆段水污染控制规划

根据水质预测结果用组合规划的方法对长江，嘉陵江重庆干流段和城区段的水污染控制提出了多个不同的方案，并对各方案进行了比较，从水质，经费和施工的可行性３个方面综合评定，筛选出优先考虑方案，同时对方案实施后的效益作出了简要的叙述。     

Revegetation of lagoon ash using the legume species Acacia auriculiformis and Leucaena leucocephala

A greenhouse study was conducted to evaluate the potential use of two legume species, Acacia auriculiformis and Leucaena leucocephala for growth on ameliorated lagoon ash with or without nitrogen (N(2))-fixing bacteria inoculation. Even though amendments of 30% (w/w) vermiculite or with sewage sludge compost were added to improve the chemical and physical limitations of lagoon ash, significant suppressions in biomass and plant nutrient content were found with ameliorated lagoon ash in comparison to an agricultural soil. The high proportion of clay-sized (<53 microm) ash particles limited root growth. In addition, heavy metal toxicity was a possible factor contributing to poor seedling growth. Higher plant productivity resulted from the sewage sludge compost-amended lagoon ash than with vermiculite due to a greater contribution of plant nutrients in the compost. Nodulation was inhibited in ameliorated lagoon ash but not in agricultural soil. High pH and electrical conductivity and elevated toxic metals may be important parameters that limit bacterial activity. Both species showed potential to establish on amended lagoon ash, with Acacia auriculiformis being the best adapted.     

Correlation relationships between physico-chemical properties and gas chromatographic retention index of polychlorinated-dibenzofurans

Correlation relationships between physico-chemical properties including vapor pressures (P), water solubilities (S), Henry's law constants (H(c)), n-octanol-water partition coefficients (K(ow)), sediment-water partition coefficient (K(pw)) and biotic lipid-water partition coefficient (K(bw), bioconcentration factor) of polychlorinated-dibenzofurans (PCDFs) and their gas chromatographic retention indices (GC-RIs) were established. A model equation between GC-RIs (= RI) and these physico-chemical properties (K) of PCDFs was in a form of log K = aRI2 + bRI + c with correlation coefficients (R2) greater than 0.94, except H(c). These equations were derived from six experimental data (five experimental data for log K(bw)) in each physico-chemical properties of PCDFs reported previously. The values of log P, log S, log H(c), log K(ow), log K(pw) and log K(bw) of PCDFs predicted by these equations based on their GC-RIs in the present study derviated from those calculated by the solubility parameters for fate analysis method in a previous study by 0.49, 0.32, 0.11, 0.34, 0.14 and 0.22 log units, respectively.     

Physiological mechanism of plant roots exposed to cadmium

Physiological experiments on plant roots exposed to cadmium were conducted on carrot and radish using a liquid culture and a pot experiment with a series of cadmium applications. Activities of four enzymes (catalase, peroxidase, polyphenol oxidase, superoxide dismutase), and concentrations of free proline and malonaldehyde in the roots of both plants were investigated. Results showed that the germination rate and growth of roots of both plants were inhibited at the concentration of 20 mg Cd/l, and the inhibition was increased with the increasing concentrations of cadmium, both in the liquid culture and in the pot experiment; activities of the four enzymes declined similarly in both species. The concentration of proline in roots reached the maximum when the application of cadmium was at the level of 20 mg/l in the liquid culture (or 20 mg/kg in soil), and then it declined slowly with the increasing concentration of cadmium. However, the reverse trend was observed for the concentration of malonaldehyde. All of bio-indicators measured here was quite sensitive to the addition of cadmium.     

The comparison of growth and nutrient removal efficiency of Chlorella pyrenoidosa in settled and activated sewage

The microscopic green alga, Chlorella pyrenoidosa was grown in settled and activated sewage under two different culture systems, batch and semi-continuous. Good growth was obtained in both types of wastewater and the algal production was comparable to and even higher than that found in commercial Bristol medium. The semi-continuous culture supported more growth than the batch system. There was a close relationship between algal growth and the amount of nutrient removed from both settled and activated sewage. A more rapid drop in NH(4)(+)-N was found in settle rather than activated sewage. The NH(4)(+)-N of settled sewage dropped from its initial 27 to 5 mg litre(-1) in both culture systems. On the other hand, the NO(3)(-)-N of activated sewage started to decrease from Day 2 onwards and the final NO(3)(-)-N concentration was less than 1 mg litre(-1) (over 90% removal efficiency). The amount of total inorganic nitrogen being reduced due to algal culture was similar in both types of sewage. The changes of phosphate content followed the same trend in both sewage, the P concentration increased slightly in the first two days then decreased, especially in the semi-continuous cultures. The final ortho-P in the sewage treated by Chlorella in semi-continuous culture was less than 5 mg litre(-1) (about 62% reduction). Such removal efficiency was slightly lower than those reported in previous studies. In general, the semi-continuous algal culture appeared to be a more suitable and efficient way for wastewater treatment than the batch system. With respect to the total reduction of wastewater inorganic N and P by means of Chlorella cells, there was no significant difference between settled and activated sewage.     

Degradation of azo dye Procion Red MX-5B by photocatalytic oxidation

The photocatalytic oxidation (PCO) of a monoazo dye Procion Red MX-5B under various physico-chemical conditions was investigated. Degradation of the dye by PCO was enhanced by augmentation in UV intensity, titanium dioxide and hydrogen peroxide concentrations but was inhibited by increase in initial dye concentration. The PCO process was affected by pH in a peculiar way. In the presence of 100 mg/l of TiO2 and the absence of H2O2, the highest reaction rate was observed when the initial pH was 10. With 500 mg/l of TiO2 and 10 mM of H2O2, the reaction was the fastest at initial pH of 3-5. The optimal conditions for the degradation of the dye, at an UV intensity of 17 mW/cm2, were determined to be: TiO2 concentration, 500 mg/l; initial H2O2 concentration, 10 mM; initial pH, 5.0. Monitoring of TOC loss showed that the dye was mineralized by 90% within 80 min under these conditions. Nevertheless, the persistence of a low level of TOC indicated that mineralization was not complete and dead-end product(s) which was (were) resistant to PCO might have accumulated.     

Removal of selected natural and synthetic estrogenic compounds in a Canadian full-scale municipal wastewater treatment plant.

The effect of a full-scale municipal wastewater treatment plant (WWTP) and each of the treatment units within the stream on the removal of endocrine-disrupting compounds was evaluated by tracking 17-beta-estradiol (E2), estrone (E1), and 17-alpha-ethinylestradiol (EE2). The overall performance of the WWTP compared well with other plants, as 90.5% removal of E1+E2 and 74.9% removal of EE2 were observed. A larger fraction of EE2 entered the plant in particulate form than E1 and E2, while a lower fraction of EE2 left the plant in particulate form than soluble form. The activated sludge units reduced the concentration of E1+E2 and EE2 in the liquid phase by 88.2% and 44.6%, respectively. The UV treatment process did not reduce the amount of estrogens. The aqueous phase of the tertiary lagoon solids contained higher levels of estrogens compared with the lagoon influent.