Bamboo charcoal addition enhanced the nitrogen removal of anammox granular sludge with COD: Performance, physicochemical characteristics and microbial community

The effects of different chemical oxygen demand (COD) concentrations on the anammox granular sludge with Bamboo Charcoal (BC) addition were evaluated in UASB reactor. The results showed that the average total nitrogen (TN) removal efficiency was reduced from 85.9% to 81.4% when COD concentration was increased from 50 to 150 mg/L. However, the TN removal efficiency of BC addition reactors was dramatically 3.1%–6.4% higher than that without BC under different COD concentrations. The average diameter of granular sludge was 0.13 mm higher than that without BC. The settling velocity was increased by elevated COD concentration, while the EPS and VSS/SS were increased with BC addition. The high-throughput Miseq sequencing analyses revealed that the bacterial diversity and richness were decreased under COD addition, and the Planctomycetes related to anammox bacteria were Candidatus Brocadia and Candidatus Kuenenia. The Metagenomic sequencing indicated that the abundance of denitrification related functional genes all increased with elevated COD, while the abundance of anammox related functional genes of decreased. The functional genes related to anammox was hydrazine synthase encoding genes (hzsA, hzsB and hzsB). The average relative abundance of hzs genes in the reactor with BC addition was higher than the control at COD concentrations of 50 mg/L and 150 mg/L. The functional genes of denitrification mediated by BC were higher than those without BC throughout the operation phase. It is interesting to note that BC addition greatly enriched the related functional genes of denitrification and anammox.     

Degradation of micropolluants in flow-through VUV/UV/H2O2 reactors: Effects of H2O2 dosage and reactor internal diameter

The degradation of atrazine (ATZ), sulfamethoxazole (SMX) and metoprolol (MET) in flow-through VUV/UV/H₂O₂ reactors was investigated with a focus on the effects of H₂O₂ dosage and reactor internal diameter (ID). Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H₂O₂ reactors following the pseudo first-order kinetics (R² > 0.92). However, the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient. With the increase of H₂O₂ dosage, the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents, which could be explained by the different reactivities of the pollutants towards HO^?. A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate, but the change in energy efficiency was much more complicated. In reality, the electrical energy per order (E_EO) of the investigated VUV/UV/H₂O₂ treatments ranged between 0.14–0.20, 0.07–0.14 and 0.09–0.26 kWh/m³/order for ATZ, SMX and MET, respectively, with the lowest E_EO for each pollutant obtained under varied H₂O₂ dosages and reactor IDs. This study has demonstrated the efficiency of VUV/UV/H₂O₂ process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors, and elaborated the influential mechanisms of H₂O₂ dosage and reactor ID on the reactor performances.     

Biochemical responses of the freshwater microalga Dictyosphaerium sp. upon exposure to three sulfonamides

Sulfonamides (SAs) are common antimicrobial drugs, which are frequently detected in surface water systems, and are difficult to degrade, posing a potential threat to the aquatic environment. However, little is known about the potential adverse effects of SAs on non-target organisms (e.g., microalgae) in the aquatic ecosystem. In this study, the effect of SAs (sulfadiazine (SD), sulfamerazine (SM1), and sulfamethazine (SM2) at 1, 5, 20, and 50 mg/L concentrations, respectively) on the freshwater microalga Dictyosphaerium sp. was investigated, with respect to changes of biomass and chlorophyll a content and induction of extracellular polymer substances (EPS), including protein and polysaccharide contents. At the same time, the residue of SAs was determined. The results showed that Dictyosphaerium sp. was tolerant to the three SAs, and the chlorophyll a content in Dictyosphaerium sp. significantly decreased on day 7, followed by a “compensation phenomena”. The increase in protein and polysaccharide contents played a defensive role in Dictyosphaerium sp. against antibiotic stress, and there was a strong positive correlation between polysaccharide contents and antibiotic concentrations. Dictyosphaerium sp. exhibited 35%–45%, 30%–42%, and 26%–51% removal of SD, SM1, and SM2, respectively. This study is helpful to understand the changes of EPS in the defense process of microalgae under the action of antibiotics, and provides a new insight for the ecological removal of antibiotic pollution in natural surface water system.     

Integrated biological–physical process for biogas purification effluent treatment

Biogas purification via water scrubbing produces effluent containing dissolved CH₄, H₂S, and CO₂, which should be removed to reduce greenhouse gas emissions and increase its potential for water regeneration. In this study, a reactor built with air supplies at the top and bottom was utilized for the treatment of biogas purification effluent through biological oxidation and physical stripping processes. Up to 98% of CH₄ was removed through biological treatment at a hydraulic retention time of 2 hr and an upper airflow rate of 2.02?L/day. Additionally, a minimum CH₄ concentration of 0.04% with no trace of H₂S gas was detected in the off gas. Meanwhile, a white precipitate was captured on the carrier showing the formation of sulfur. According to the developed mathematical model, an upper airflow rate of greater than 2.02?L/day showed a small deterioration in CH₄ removal performance after reaching the maximum value, whereas a 50?L/day bottom airflow rate was required to strip the CO₂ efficiently and raise the effluent pH from 5.64 to 7.3. Microbiological analysis confirmed the presence of type 1 methanotroph communities dominated by Methylobacter and Methylocaldum. However, bacterial communities promoting sulfide oxidation were dominated by Hyphomicrobium.     

Physiological and biochemical responses of Microcystis aeruginosa to phosphine (PH3) under elevated CO2

Phosphine (PH₃) is an important factor driving the outbreak of cyanobacterial blooms that produce toxic microcystin threating human health. To clarify the physiological and biochemical responses of cyanobacteria to PH₃ under elevated CO₂ concentration, Microcystis aeruginosa was used in the coupling treatment of 1000 ppmv CO₂ and PH₃ at different concentrations respectively. The chlorophyll a (Chl-a), carotenoid, net photosynthetic rate and total protein of M. aeruginosa exhibited evidently increasing tendency under the coupling treatment of 1000 ppmv CO₂ and PH₃ at different concentrations (7.51 × 10^?3, 2.48 × 10^?2, 7.51 × 10^?2 mg/L). The coupling treatments resulted in the higher concentrations of Chl-a and carotenoid of M. aeruginosa, compared to those in the control and the treatment with CO₂ alone, and their enhancement increased with the increase in PH₃ concentrations. The total antioxidant capacity (T-AOC) in the coupling treatment with CO₂ and PH₃ of 2.48 × 10^?2 mg/L and 7.51 × 10^?3 mg/L showed increasing tendency, compared to the treatment with PH₃ alone. Additionally, the coupling treatment with 1000 ppmv CO₂ and PH₃ also altered the pH and DO level in the culture medium. In this regard, the coupling treatment with CO₂ and PH₃ at an appropriate concentration can enhance the resistance of M. aeruginosa to PH₃ toxicity and is beneficial to the reproduction of M. aeruginosa, presumably resulting in potential for the outbreak of cyanobacteria bloom. Given the concern about global warming and the increase in atmospheric CO₂ level, our research laid a foundation for the scientific understanding of the correlation between PH₃ and cyanobacteria blooms.     

Effect of intermittent aeration mode on nitrogen concentration in the water column and sediment pore water of aquaculture ponds

Nitrogen in pond sediments is a major water quality concern and can impact the productivity of aquaculture. Dissolved oxygen is an important factor for improving water quality and boosting fish growth in aquaculture ponds, and plays an important role in the conversion of ammonium-nitrogen (NH₄⁺-N) to nitrite-nitrogen (NO₂^?-N) and eventually nitrate-nitrogen (NO₃^?-N). A central goal of the study was to identify the best aeration method and strategy for improving water quality in aquaculture ponds. We conducted an experiment with six tanks, each with a different aeration mode to simulate the behavior of aquaculture ponds. The results show that a 36 hr aeration interval (T_c = 36 hr: 36 hr) and no aeration resulted in high concentrations of NH₄⁺-N in the water column. Using a 12 hr interval time (T_c = 12 hr: 12 hr) resulted in higher NO₂^?-N and NO₃^?-N concentrations than any other aeration mode. Results from an 8 hr interval time (T_c = 8 hr: 8 hr) and 24 hr interval time (T_c = 24 hr: 24 hr) were comparable with those of continuous aeration, and had the benefit of being in use for only half of the time, consequently reducing energy consumption.     

Anaerobic digestion in mesophilic and room temperature conditions: Digestion performance and soil-borne pathogen survival

Tomato plant waste(TPW) was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS(total solid) concentrations of 2%, 4% and 6% respectively, at mesophilic(37 ± 1°C) and room(20–25°C) temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416 L/kg VS(volatile solids). The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR(polymerase chain reaction) were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA(volatile fatty acid) concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety.     

The study of biological activity of transformation products of diclofenac and its interaction with chlorogenic acid

In the present work we compared the biological activity of DCF, 4′-OHDCF and 5-OHDCF as molecules of most biodegradation pathways of DCF and selected transformation products (2-hydroxyphenylacetic acid; 2,5-dihydroxyphenylacetic acid and 2,6-dichloroaniline) which are produced during AOPs, such as ozonation and UV/H₂O₂. We also examined the interaction of DCF with chlorogenic acid (CGA). CGA is commonly used in human diet and entering the environment along with waste mainly from the processing and brewing of coffee and it can be toxic for microorganisms included in activated sludge. In the present experiment the evaluation of following parameters was performed: E. coli K-12 cells viability, growth inhibition of E. coli K-12 culture, LC₅₀ and mortality of Chironomus aprilinus, genotoxicity, sodA promoter induction and ROS generation. In addition the reactivity of E. coli SM recA:luxCDABE biosensor strain in wastewater matrices was measured. The results showed the influence of DCF, 4′-OHDCF and 5-OHDCF on E. coli K-12 cells viability and bacteria growth, comparable to AOPs by-products. The highest toxicity was observed for selected, tested AOPs by-products, in comparison to the DCF, 4′-OHDCF and 5-OHDCF. Genotoxicity assay indicated that 2,6-dichloroaniline (AOPs by-product) had the highest toxic effect. The oxidative stress assays revealed that the highest level of ROS generation and sodA promoter induction were obtained for DCF, 4′-OHDCF and 5-OHDCF, compared to other tested compounds. We have also found that there is an interaction between chlorogenic acid and DCF, which resulted in increased toxicity of the mixture of the both compounds to E. coli K-12, comparable to parent chemicals. The strongest response of E. coli SM biosensor strain with recA:luxCDABE genetic construct in filtered treated wastewaters, comparable to control sample was noticed. It indicates, that E. coli SM recA:luxCDABE biosensor strains is a good tool for bacteria monitoring in wastewater environment. Due to toxicity and biological activity of tested DCF transformation products, there is a need to use additional wastewater treatment systems for wastewater contaminated with pharmaceutical residues.     

Adsorption kinetics of the herbicide safeners, benoxacor and furilazole, to activated carbon and agricultural soils

Chloroacetamide herbicides, namely acetochlor and metolachlor, are common herbicides used on corn and soybean fields. Dichloroacetamide safeners, namely benoxacor and furilazole, are commonly used in formulations containing chloroacetamide herbicides. Extensive reports on adsorption of chloroacetamide herbicides are available, yet little information exists regarding adsorption potential of co-applied safeners. Herein, the adsorption and desorption characteristics of selected herbicide safeners to granular activated carbon (GAC) and in agricultural soils are reported. Further, soil column studies were performed to understand the leaching behaviour of the herbicide Dual II Magnum. Equilibrium sorption experiments of safeners to three agricultural soils and one GAC showed that adsorption was best fitted by the Freundlich isotherm. The Freundlich adsorption constant, K_f, for benoxacor and furilazole sorption onto three agricultural soils ranged from 0.1 to 0.27 and 0.1 to 0.13 (mg/g) × (mg/L)?(1/n), respectively. The K_f for benoxacor and furilazole to GAC was 6.4 and 3.4 (mg/g) × (mg/L)?(1/n), respectively, suggesting more favorable sorption of benoxacor to GAC than furilazole to GAC. The sorption to soils was reversible as almost 40%–90% of both safeners was desorbed from three soils. These results were validated in four replicated soil column studies, where S-metolachlor was shown to leach similarly to the safener benoxacor, originating from the herbicide formulation. The leaching of S-metolachlor and benoxacor was influenced by soil texture. Cumulatively, these results show that safeners will move through the environment to surface waters similarly to the active ingredients in herbicides, but may be removed during drinking water treatment via GAC.     

Influence of seasonal temperature change on autotrophic nitrogen removal for mature landfill leachate treatment with high-ammonia by partial nitrification-Anammox process

In this study, a denitrification (DN)–partial nitritation (PN)–anaerobic ammonia oxidation (Anammox) system for the efficient nitrogen removal of mature landfill leachate was built with a zone-partitioning self-reflux biological reactor as the core device, and the effects of changes in seasonal temperature on the nitrogen removal in non-temperature-control environment were explored. The results showed that as the seasonal temperature decreased from 34°C to 11.3°C, the total nitrogen removal rate of the DN-PN-Anammox system gradually decreased from the peak value of 1.42 kg/(m³?day) to 0.49 kg/(m³?day). At low temperatures (<20°C), when the nitrogen load (NLR) of the system is not appropriate, the fluctuation of high NH₄⁺-N concentration in the landfill leachate greatly influenced the stability of the nitrogen removal. At temperatures of 11°C–15°C, the NLR of the system is controlled below 0.5 kg/(m³?day), which can achieve stable nitrogen removal and the nitrogen removal efficiency can reach above 96%. The abundance of Candidatus Brocadia gradually increased with the decrease of temperature. Nitrosomonas, Candidatus Brocadia and Candidatus Kuenenia as the main functional microorganisms in the low temperature.     

装置施工和检修中法兰、垫片的更换和选择

文章对法兰、垫片泄漏对石油化工企业的安全、环保造成的威胁进行了分析，提出在设计中合理选用管道器材是保证管道和设备正常运行的关键。     

普光气田腐蚀防控技术研究与应用

普光气田高含H2S(13%~18%)和CO2(8%~10%),输送介质对站场及管道的腐蚀问题需从设计、选材、内外防腐、腐蚀监测、控制保护等多方面进行考虑,确保气田的安全平稳可控进行。     

月亮高度及升降时刻与方位的计算

本文编制了计算某地理位置、某一天月亮的出升下降时刻和方位、月亮最高高度和某一时刻月亮高度和方位的计算程序 ,并对程序进行了检验。以防灾技术高等专科学校三楼实训室的地理坐标 (116°4 7 6 31′E ,39°5 7 0 90′N)为例 ,计算了防灾技术高等专科学校 2 0 0 2年 12月 30日 9点 5 4分 30秒的各参数值。     

环境科学与工程专业实践教学环节的探讨

当今社会中国的环境问题日益突出,人民群众的环境意识日益加强,随之而来的对环境科学与工程高技术人才的需求量越来越大,同时对环境科学与工程高技术人才的要求也越来越高。在培养具有高竞争能力和创新精神的复合型高素质环境专业人才的过程中,实践教学环节显得尤为重要。锻炼和提高学生的动手能力和实践能力,培养学生的创新精神,是提高学生在社会中竞争力的关键。文中分析了环境科学与工程专业实践教学环节中存在的主要问题;提出了从实验教学及工程设计环节、实习环节到毕业设计环节进行改革,增强实践教学的内容,改进实践教学的方法。     

真菌和细菌对染料的吸附脱色及再生能力的研究

进行了真菌和细菌共培养对染料的吸附脱色和吸附脱色能力再生的研究。结果表明，青霉菌G－1首先对偶氮染料S－119、蒽醌染料艳紫KN－B（C．I．Reactive violet 22）水溶液中染料进行快速吸附去除，菌丝对同种染料的吸附速度随菌丝培养液中葡萄糖浓度的增加而加快，吸附染料的G－1菌丝在与细菌的共培养中完成对染料的脱色降解，脱色速度受培养液中葡萄和氮源浓度影响较大，从吸附速率和完全脱色时间综合评价，以葡萄糖浓度为5g/L、酒石酸铵为20mmol/L的培养基中培养的菌丝对染料的吸附脱色效果最好，吸附在菌丝上的艳紫KN－B脱色后菌丝吸附脱色能力得到再生，菌丝对100mg/L的艳紫KN－B染料水溶液可重复处理4次。青霉菌G－1对酸性染料废水处理3h，色度去除率为75．9％，吸附染料的菌丝在与细菌共培养中完成对染料的脱色，对试验所用染料废水，菌丝的处理能力获得1次再生。     

铅镉胁迫下接种根际细菌和真菌对圆叶无心菜生长和铅镉累积的影响

铅镉胁迫条件下,采用盆栽试验,研究接种云南会泽铅锌矿区Cd超累积植物-圆叶无心菜的根际细菌和真菌,对圆叶无心菜的生长和铅镉累积的影响,结果表明：2株根际真菌（YQ2F-5和YG2F-6）显著增加盆栽圆叶无心菜地上部分的生长,1株根际真菌（YQF-5）显著增加盆栽圆叶无心菜的生物量.根际细菌对盆栽圆叶无心菜的生长和生物量没有影响.接种根际细菌和真菌对盆栽圆叶无心菜Pb和Cd的吸收累积没有影响.     

砷的污染、检测与防治

在环境化学污染物中,砷是最常见、最严重的污染物之一.随着现代工农业生产的发展,砷对环境的污染日趋严重.为了更好地评价砷污染对环境和人体的影响,介绍了砷污染的来源、对人体的危害、标准的检测方法和目前砷污染治理的现状.     

国内外关于"轻柴油"安全标准规范的概况与比较

新“轻柴油”产品标准将轻柴油的闪点指标由原来的≥65℃改为≥55℃，由此导致轻柴油的火灾危险类别发生变化，并进而引发原有轻柴油储罐能否安全储存新标准轻柴油的问题。本文就此对国内外有关“轻柴油”的安全标准和规范进行了分析比较，以期能对我国轻柴油的安全储存提供一些资料方面的参考。     

区域物质流规模结构分析评价方法及应用研究

生态经济体系中环境的引导和调控作用是经济系统物质代谢的重要组成部分.为了更为完善地分析评价经济发展和环境压力的关系,在输入端、输出端物质流规模和结构分析中侧重于物质隐藏流的综合计算,并以广州市南沙区为例进行实证研究.研究结果表明:南沙区域出口与出口物质隐藏流呈逐步上升趋势;南沙区的区内生产过程排放呈现"先降后增、总体递增"的趋势,今后南沙区应加强对工业生产过程中工业固废和二氧化硫排放的监控.     

MBR与SMBR脱氮除磷特性及膜污染控制

为提高污水深度处理效能和工艺运行的稳定性,研究以序批式膜生物反应器(SMBR)与传统膜生物反应器(MBR)为对象,对比研究其脱氮除磷特性、缺氧时间对工艺效率的影响及膜污染控制策略,同时应用分子生物学技术对两种工艺中微生物群落结构和组成进行分析.结果表明,间歇曝气能强化系统脱氮,使SMBR工艺去除总氮效果优于MBR,而在氨氮、总磷、COD、浊度去除方面两者无明显差异,去除率分别为94%、78%、80%、97%.延长SMBR工艺缺氧时间对COD、氨氮去除无显著影响,降低了总氮、总磷的去除率,总氮去除率由61%下降到46%,总磷由74%下降到52%.采用间歇曝气和投加一定浓度的粉末活性炭(PAC)均有利于减缓膜污染.微生物群落分析发现,两种工艺中微生物群落结构和组成无显著差异,硝化螺菌属(Nitrospira)和脱氯单胞菌属(Dechloromonas)为系统中的高丰度功能菌群,为工艺高效运行提供了生物学基础.