文明的衰败与启迪

人类历史上产生了古代埃及、古代两河流域、古代印度、古代希腊、古代印加、古代中国等光辉灿烂的文明,但都出现了由于人为因素引起的生态破坏带来的文明衰败的现象,留下深刻的经验教训和启迪。人类必须尊重自然、善待自然、也必须师法自然、遵循自然规律,还必须保护环境、保护自然、维护生态环境的平衡与和谐,只有如此人类文明将会走向光辉的彼岸。     

环境中多环芳烃(PAHs)的生物标志物的功效分析

污染物的生物监测一直是环境风险评估研究的重要内容.肝脏中谷胱甘肽硫转移酶(glutathione-S -transferase,GST)、7-乙氧基-3-异吩恶唑酮-脱乙基酶(ethoxyresorufin-O-deethylase,EROD)、DNA-加合物(DNA-adducts)和胆汁中多环芳烃代谢物(PAH m...     

Optimum conditions for the formation of Al13 polymer and active chlorine in electrolysis process with Ti/RuO2-TiO2 anodes

A polyaluminum containing a high concentration of Al₁₃ polymer and active chlorine (PACC) was successfully synthesized by a new electrochemical reactor using Ti/RuO₂-TiO₂ anodes. PACC can potentially be used as a dual-function chemical reagent for water treatment. The obtained results indicated that the formation of Al₁₃ polymer and active chlorine, were the most active components in PACC responsible for coagulation and disinfection respectively. These components were significantly influenced by electrolyte temperature, current density, and stirring rate. It was observed that high electrolyte temperature favored the formation of Al₁₃. Increasing current density and stirring rate resulted in high current efficiency of chlorine evolution, thus favoring the generation of Al₁₃ and active chlorine in PACC. When the PACC (Al_T = 0.5 mol/L, basicity = 2.3) was prepared at the optimum conditions by electrolysis process, the Al₁₃ polymer and active chlorine in product reached above 70% of Al_T and 4000 mg/L, respectively. In the pilot scale experiment with raw polyaluminum chloride used as an electrolyte, PACC was successfully prepared and produced a high content of Al₁₃ and active chlorine products. The pilot scale experiment demonstrated a potential industrial approach of PACC preparation.     

AHLs群体感应信号分子对硝化污泥附着生长及硝化效果的影响

污水生物脱氮系统中的硝化菌生长慢、易流失,人为添加N-酰基高丝氨酸内酯类(AHLs)群体感应信号分子,可能会强化硝化菌生物膜的形成,从而有助于富集硝化菌,提高硝化效率.本研究以采用低碳氮比(C∶N=8)人工配置废水驯化100 d后的硝化活性污泥为菌源,人为外加2μmol·L-1的AHLs信号分子(C8-HSL或OHHL),分析了两种信号分子对硝化污泥静态附着、氨氮动态降解及微生物生长速率的影响.研究结果表明,信号分子OHHL能快速强化微生物附着生长,且能在一定时间内持续发挥作用,有助于硝化生物膜的形成;而信号分子C8-HSL则能明显提高硝化污泥的氨氮降解速率;两种信号分子都能促进硝化污泥生长,提高微生物生长速率,增强硝化污泥活性,加速硝化污泥生物量累积.人为添加C8-HSL或OHHL信号分子,不仅能保证氨氮降解效率还能降低出水硝氮浓度,减轻氮污染.     

用边际费用分析方法研究制定排污收费的新标准

排污收费的有效性主要取决于它的经济刺激作用。本文分析了排污收费的经济学原理,提出了制定排污收费标准更为合理有效的方法──边际费用分析法,定量地描述和分析了排污收费与其经济刺激作用的关系,以天津纪庄子污水处理厂为例,提出应建立的排污收费标准。本文指出,有效地运用排污收费来管理污水的排放,必须实行区域总量控制,制定具有有效的经济刺激作用的排污收费标准。     

非水相硝基苯在含水层中的迁移释放规律

通过室内模拟实验,探讨了在非水相硝基苯污染含水层的条件下,其在含水层中的迁移及释放规律。迁移规律表明,非水相硝基苯并非在含水层中直接进行垂向迁移,而是一方面在自身重力作用下向含水层下部迁移,另一方面在地下水流的作用下随地下水同向运移,整体表现为随地下水流的侧向运移,并最终迁移至含水层底部。释放规律表明,非水相硝基苯在含水层迁移的过程中会向地下水大量释放,释放出的硝基苯在水流的作用下随地下水同向运移,污染源及迁移至含水层底部的非水相硝基苯均存在再次释放。     

Phytoplankton photosynthetic adaptation to high frequency light fluctuations simulating those induced by sea surface waves

In order to test the ability of phytoplankton to adapt to the high frequency light fluctuations induced by sea surface waves, the green alga Dunaliella tertiolecta was grown under both steady and fluctuating (0.1, 1.0 and 10 Hz) illuminations. The latter conditions reproduced those fluctuations experienced by phytoplankton in the upper photic layer. For each culture, photosynthesis versus irradiance were measured under four incubation frequencies (steady, 0.1, 1.0 and 10 Hz fluctuating illuminations). Results indicated that growth rates were similar for algae grown under steady light and 10 Hz fluctuating light (0.26–0.33 d^–1). Cells grown at 0.1 and 1.0 Hz showed lower growth rates (0.17–0.26 d^–1). Chlorophyll a and b were significantly higher under 0.1 and 10 Hz frequencies than under steady illumination; at 1.0 Hz, there were no significant differences with steady light. No changes in carotenoids were evidenced at any frequency tested. Photosynthetic measurements showed that algae grown under steady illumination had higher photosynthetic efficiency and capacity when incubated under steady and 0.1 Hz fluctuating light. Photosynthetic characteristics of algae grown under 0.1 Hz illumination did not show any clear responses to fluctuating light. Algae grown under 1.0 or 10 Hz had higher photosynthetic efficiency and capacity than those grown under steady illumination, when incubated under 1.0 and 10 Hz light. This suggests that microalgae grown under high frequency illumination (1.0 and 10 Hz) can adapt their photosynthetic characteristics to the rapidly fluctuating light regime experienced during growth, and that algae grown under steady conditions respond better to steady or slowly fluctuating (0.1 Hz) light. Such an adaptation provides a means of probing the photosynthetic responses of phytoplankton to vertical mixing.Contribution to the program of GIROQ (Groupe interuniversitaire de recherches océanographiques du Québec)     

炉渣用于深层过滤的试验研究

将炉渣用作深层过滤的床层过滤,在油田水处理中具有良好的应用前景。通过对炉渣滤料的物性测定,对流体力学性能、过滤性能及反洗性能的研究,获得了有关炉渣滤料的粒径分布、床层孔隙率、密度、吸水率等物性参数,以及清洁滤料床层阻力与速度的关系曲线和流化曲线,过滤条件下床层阻力随时间的变化关系和悬浮物脱除率随时间的变化曲线,炉渣床层的反洗曲线。结果表明：炉渣表面粗糙,有棱角,吸附表面积大,孔隙率大,过滤效果好;炉渣滤料密度小,反洗效果较好,反洗用水量只是过滤水量的５％左右;同时,炉渣作为滤料用于深层过滤,不仅来源广泛,而且属废物利用。     

Removal of alachlor from water by catalyzed ozonation in the presence of Fe2+, Mn2+, and humic substances

The effects of Fe(II), Mn(III) and humic substances on the catalyzed ozonation of alachlor, an endocrine disruptor were investigated. Results revealed that small amounts of Fe(II), Mn(II), and humic substances could enhance the ozonation of alachlor, but larger amounts of them would retard the oxidation. These results were successfully identified by an electron paramagnetic resonance (EPR) spectroscopy spin-trapping method that could quantify hydroxyl radicals. The production of hydroxyl radicals was obviously increased with the increasing of Fe(II) concentration, which contributed to enhance ozonation at low concentrations. But the excess Fe(II) consumed some of the radicals when it was added at a higher concentration (1.5 mg/L). However, no obvious radicals were observed when a different amount of Mn(II) was used, and the catalytic ozonation of alachlor by Mn(II) mainly followed the mechanism of "active sites created on the surface of MnO2." The radical pathway was followed when alachlor was ozonated with different concentrations of humic substances because of its radical initiating, promoting, and inhibiting effects.     

Comparison of the effects of aluminum and iron(Ⅲ) salts on ultrafiltration membrane biofouling in drinking water treatment

Coagulation plays an important role in alleviating membrane fouling, and a noticeable problem is the development of microorganisms after long-time operation, which gradually secrete extracellular polymeric substances(EPS). To date, few studies have paid attention to the behavior of microorganisms in drinking water treatment with ultrafiltration(UF)membranes. Herein, the membrane biofouling was investigated with different aluminum and iron salts. We found that Al_2(SO_4)_3·18 H_2O performed better in reducing membrane fouling due to the slower growth rate of microorganisms. In comparison to Al_2(SO_4)_3·18H_2O,more EPS were induced with Fe_2(SO_4)_3·x18H_2O, both in the membrane tank and the sludge on the cake layer. We also found that bacteria were the major microorganisms, of which the concentration was much higher than those of fungi and archaea. Further analyses showed that Proteobacteria was dominant in bacterial communities, which caused severe membrane fouling by forming a biofilm, especially for Fe_2(SO_4)_3·x18H_2O. Additionally, the abundances of Bacteroidetes and Verrucomicrobia were relatively higher in the presence of Al_2(SO_4)_3·18 H_2O,resulting in less severe biofouling by effectively degrading the protein and polysaccharide in EPS. As a result, in terms of microorganism behaviors, Al-based salts should be given preference as coagulants during actual operations.