Fenton氧化法深度处理抗生素废水二级出水

采用Fenton氧化法对青霉素和土霉素混合废水二级处理出水进行深度处理,通过正交和单因素实验研究了废水初始反应pH值、H2O2投加量、Fe2+/H2O2摩尔比及反应时间等因素对废水处理效果的影响。实验结果表明,Fenton氧化法处理的最佳反应条件为:初始pH值4、H2O2(30%)投加量50 mL/L、Fe2+/H2O2摩尔比1/20和反应时间60 min,处理后出水COD小于120 mg/L,COD去除率在75%以上,急性毒性(HgCl2毒性当量)小于0.07 mg/L,满足《发酵类制药工业水污染物排放标准》(GB21903-2008)表2标准要求。     

城市污水条件下ASBR厌氧氨氧化的启动与脱氮性能

采用ASBR在城市污水条件下进行厌氧氨氧化的启动与脱氮性能研究。实验接种好氧硝化污泥,在温度为(35±1)℃、HRT为24 h、pH为7.3～8.5的条件下经过130 d的培养,成功启动了厌氧氨氧化反应。实验结果表明,厌氧氨氧化反应稳定运行时,TN容积负荷平均为0.179 kg/(m3.d),NH4+-N、NO2--N和TN去除率分别达到了95.30%、91.30%和76.28%。启动期和稳定运行期NH4+-N、NO2--N去除量和NO3--N生成量的比值分别达到1∶1.54∶0.25和1∶1.27∶0.27;稳定运行期进出水pH差值由启动时的0.85下降到0.24。启动期反硝化和厌氧氨氧化反应同时存在而在稳定运行期厌氧氨氧化发展成为主导反应。MLSS和MLVSS/MLSS先减少后增加,反映了启动过程中硝化细菌、反硝化细菌的衰亡和厌氧氨氧化菌逐渐富集的过程,这与反应器的宏观运行效果相一致。     

页岩气开采中压裂废液处理技术的发展及应用

作为新型的天然气资源,近年来页岩气的开采力度不断增加。文章广泛调研页岩气开采过程中的场地修复、压裂废液处理等方面的环境污染风险,国内外现行压裂废液的处理工艺,系统分析了中和法、絮凝法和氧化法等处理工艺,并结合实际应用效果和企业需求对技术发展方向进行了预测,可为非常规油气资源开发领域提供理论参考。     

油田压裂返排液处理技术实验研究

油气井压裂作业过程中产生的压裂返排液已成为当前油田水体的主要污染源之一。文章对吉林油田公司压裂返排液处理工艺进行了实验研究。结果表明:在采用絮凝、微波强氧化、活性炭毡处理、纳滤/反渗透集成处理工艺后,压裂返排液CODCr可以达到GB 8978-1996《污水综合排放标准》一级标准要求。该研究为压裂返排液处理装置的设计和现场实施提供了实验基础。     

三级生物接触氧化除油生化池的生物膜特性

将生物接触氧化技术用于油田稠油污水的处理,在三级串联运行的生物接触氧化池中,生物膜特性主要由生物膜上原油成分决定。在沿水流方向上,生物膜上易降解原油组分含量降低,难降解组分含量上升,第一级生化池中的生物膜厚度和优势菌种数量明显超过第二级和第三级,藻类主要生长在一级生化池的后部和二、三级生化池中的生物膜上,原生动物出现在二级和三级生化池生物膜上,而后生动物只出现在三级生化池生物膜上。     

光催化氧化处理低浓度含醇废水实验

室内实验了TiO2紫外光催化氧化处理废水中的低浓度甲醇。通过对TiO2催化剂活性及添加方式、溶液pH、紫外光强与催化剂加量等参数优化,在TiO2加入浓度为300mg/L和120 W紫外灯照射条件下,对6.8L甲醇浓度为2.77%的低浓度含醇废水持续处理70min后,废水中的甲醇去除率可达98.31%。该实验为进一步处理低浓度含醇废水提供了方法依据。     

Treatment of coking wastewater by an advanced Fenton oxidation process using iron powder and hydrogen peroxide

In this study the treatment of coking wastewater was investigated by an advanced Fenton oxidation process using iron powder and hydrogen peroxide. Particular attention was paid to the effect of initial pH, dosage of H₂O₂ and to improvement in biodegradation. The results showed that higher COD and total phenol removal rates were achieved with a decrease in initial pH and an increase in H₂O₂ dosage. At an initial pH of less than 6.5 and H₂O₂ concentration of 0.3 M, COD removal reached 44-50% and approximately 95% of total phenol removal was achieved at a reaction time of 1 h. The oxygen uptake rate of the effluent measured at a reaction time of 1 h increased by approximately 65% compared to that of the raw coking wastewater. This indicated that biodegradation of the coking wastewater was significantly improved. Several organic compounds, including bifuran, quinoline, resorcinol and benzofuranol were removed completely as determined by GC-MS analysis. The advanced Fenton oxidation process is an effective pretreatment method for the removal of organic pollutants from coking wastewater. This process increases biodegradation, and may be combined with a classical biological process to achieve effluent of high quality.     

Photocatalytic degradation of five sulfonylurea herbicides in aqueous semiconductor suspensions under natural sunlight

In the present study, the photocatalytic degradation of five sulfonylurea herbicides (chlorsulfuron, flazasulfuron, nicosulfuron, sulfosulfuron and triasulfuron) has been investigated in aqueous suspensions of zinc oxide (ZnO), tungsten (VI) oxide (WO₃), tin (IV) oxide (SnO₂) and zinc sulfide (ZnS) at pilot plant scale under natural sunlight. Photocatalytic experiments, especially those involving ZnO photocatalysis, showed that the addition of semiconductors in tandem with the oxidant (Na₂S₂O₈) strongly enhances the degradation rate of the herbicides in comparisons carried out with photolytic tests. The degradation of the herbicides follows a first order kinetics according to the Langmuir-Hinshelwood model. In our conditions, the amount of time required for 50% of the initial pesticide concentration to dissipate (t_½) ranged from 8 to 27 min (t_30W = 0.3-1.2 min) for sulfosulfuron and chlorsulfuron, respectively in the ZnO/Na₂S₂O₈ system. None of the studied herbicides was found after 120 min of illumination (except chlorsulfuron, 0.2 μg L⁻¹).     

Catalytic destruction of pentachlorobenzene in simulated flue gas by a V2O5-WO3/TiO2 catalyst

Pentachlorobenzene (PeCB) in simulated flue gas was destructed by a commercial V₂O₅-WO₃/TiO₂ catalyst in this study. The effects of reaction temperature, oxygen concentration, space velocity and some co-existing pollutants on PeCB conversion were investigated. Furthermore, a possible mechanism for the oxidation of PeCB over the vanadium oxide on the catalysts was proposed. Results show that the increase of gas hourly space velocity (GHSV) and the decrease of operating temperature both resulted in the decrease of PeCB removal over the catalyst, while the effect of the oxygen content in the range of 5-20% (v/v) on PeCB conversion was negligible. PeCB decomposition could be obviously affected by the denitration reactions under the conditions because of the positive effect of NO but negative effect of NH₃. The introduction of SO₂ caused the catalyst poisoning, probably due to the sulfur-containing species formed and deposited on the catalyst surface. The PeCB molecules were first adsorbed on the catalyst surface, and then oxidized into the non-aromatic acyclic intermediates, low chlorinated aromatics and maleic anhydride.     

Whole effluent toxicity assessment at a wastewater treatment plant upgraded with a full-scale post-ozonation using aquatic key species

Ozonation as final wastewater (WW) polishing step, following conventional activated sludge treatment is increasingly implemented in sewage treatment for contaminant degradation to prevent surface water pollution. While the oxidative degradation of chemicals has been extensively investigated, the in vivo toxicological characteristics of ozonated whole effluents are rarely a matter of research.In the present study, whole effluents were toxicologically evaluated with an in vivo test battery before and after full-scale ozonation and subsequent sand filtration on site at a treatment plant. One aquatic plant (duckweed, Lemna minor) and five invertebrate species of different systematic groups (Lumbriculus variegatus, Chironomus riparius, Potamopyrgus antipodarum, Daphnia magna) were exposed to the effluents in a flow-through-designed test system with a test duration of 7-28 d.None of the considered toxicity endpoints correlated with the pollutant elimination. A tendency towards an increased toxicity after ozonation was apparent in three of the test systems showing [statistically] significant adverse effects in the L. variegatus toxicity test (decrease in reproduction and biomass). After sand filtration, adverse effects were reduced to a similar level like after conventional treatment. Solely the Daphnia reproduction test revealed beneficial effects after ozonation in combination with sand filtration.Results of the test battery indicate the formation of adverse oxidation products during WW ozonation. L. variegatus appeared to be the most sensitive of the five test species. Sand filtration effectively removes or detoxifies toxic oxidation products, as toxic effects were subsequently reduced to the level after conventional treatment.