pH和元素摩尔比对污泥酸化液沉淀法脱氮除磷的影响

针对剩余污泥水解酸化产生大量多糖、蛋白质和VFAs碳源的同时会有较高浓度的NH+4-N和PO3-4-P溶出的问题,考察了pH值和元素摩尔比对以沉淀法同时去除NH+4-N和PO3-4-P的影响.结果表明,最佳pH为9.0,当pH升高到10.0时NH+4-N去除率略有下降,在特定摩尔比范围内摩尔比对沉淀形成的影响大于pH值...     

Spatio-temporal variations of nitrogen in an agricultural watershed in eastern China: catchment export, stream attenuation and discharge

Using the monthly hydrogeochemical data of ChangLe River system from 2004 to 2008, total nitrogen (TN) export load (S(n)) from nonpoint sources (NPS) to stream and in-stream attenuation load (A(L)) was estimated by the inverse and forward format of an existing in-stream nutrient transport equation, respectively. Estimated S(n) contributed 96 ± 2% of TN entering the river system, while A(L) reduced the input TN by 23 ± 14% in average. In-stream TN attenuation efficiency in high flow periods (10 ± 5% in average for the entire river system) was much lower than that in low flow periods (39 ± 17%). TN attenuation efficiency in tributaries (28 ± 16% in average) was much higher than that in mainstream (11 ± 8%). Hydrological conditions are important in determining the spatio-temporal distributions of NPS TN export, stream attenuation and discharge. Increasing the water residence time might be a practical method for mitigating stream TN.     

Biotoxicity of nickel oxide nanoparticles and bio-remediation by microalgae Chlorella vulgaris

Adverse effects of manufactured nickel oxide nanoparticles on the microalgae Chlorellavulgaris were determined by algal growth-inhibition test and morphological observation via transmission electron microscopy (TEM). Results showed that the NiO nanoparticles had severe impacts on the algae, with 72 h EC(50) values of 32.28 mg NiOL(-1). Under the stress of NiO nanoparticles, C. vulgaris cells showed plasmolysis, cytomembrane breakage and thylakoids disorder. NiO nanoparticles aggregated and deposited in algal culture media. The presence of algal cells accelerated aggregation of nanoparticles. Moreover, about 0.14% ionic Ni was released when NiO NPs were added into seawater. The attachment of aggregates to algal cell surface and the presence of released ionic Ni were likely responsible for the toxic effects. Interestingly, some NiO nanoparticles were reduced to zero valence nickel as determined by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The maximum ratios of nickel reduction was achieved at 72 h of exposure, in accordance with the time-course of changes in soluble protein content of treated C. vulgaris, implying that some proteins of algae are involved in the process. Our results indicate that the toxicity and bioavailability of NiO nanoparticles to marine algae are reduced by aggregation and reduction of NiO. Thus, marine algae have the potential for usage in nano-pollution bio-remediation in aquatic system.     

Concentrations and inventories of polycyclic aromatic hydrocarbons and organochlorine pesticides in watershed soils in the Pearl River Delta,China

The concentration levels, source, and inventories of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in 55 surface vegetable soils in the watershed of the Pearl River Delta (PRD) were analyzed and compared with those of the surface sediments in the Pearl River Estuary (PRE) and northern South China Sea (SCS). The 16 priority PAHs on US EPA list range from 58 to 3,077 microg/kg (average: 315 microg/kg). The concentrations of DDTs and HCHs range from 3.58 to 831 microg/kg (average: 82.1 microg/kg) and from 0.19 to 42.3 microg/kg (average: 4.42 microg/kg). The ratios of DDT/ (DDD+DDE) are higher than 2 in majority of the soil samples, suggesting that DDT contamination still exists. The PAH ratios suggest that the source of PAHs is petroleum, and combustion of fossil fuel, biomass, and coal. The average concentrations of PAHs and the linear regression slope between PAHs and TOC for the soils and the sediments are quite similar. It was estimated that the soil mass inventories at 0-20 cm depth are 1,292 metric tons for PAHs and 356 metric tons for OCPs in the studied region. The average PAHs inventory per unit area for the soil samples investigated in PRD is about 0.86 time that of surface sediments in the Pearl River Estuary, and about 2.43 times that of surface sediments in the northern South China Sea. PAHs in the soils in PRD have similar source to those of the surface sediments in PRE. All of those may suggest that PAHs in PRE and SCS are probably mainly inputted from the soils in PRD via soil erosion and river transport.     

土壤微生物降解石油污染物

调查分析了石油污染程度不同的土壤的嗜油微生物分布状况，通过梯度浓度驯化、半连续紫外诱变、梯度浓度再驯化，建立了一套可操作的嗜油细菌筛选办法，对6株优势菌及其混合菌进行了石油降解率及脱氢酶活性分析测试，得到了3株高效石油降解菌，经初步鉴定分别为假单胞菌属（Pseudomonas)、微球菌属（Micrococcus)、黄单胞Xanthomonas)。     

Effect of airborne SO_2 on performance of the turnip moth,Agrotis segetum Schiff

SO2 Pollution; rape plant (Brassica chinensis); turnip moth (Agrotis segetum); growth and developmental parameters.     

沈阳市苏家屯区危险废物管理、处置现状与对策

对沈阳市苏家屯区危险废物现状进行了调查,分析了危险废物的来源、产生量、特征及存在的主要问题。在此基础上,提出对危险废物管理处置对策,包括开展危险废物申报登记;加强苏家屯区危险废物监督管理;源头控制危险废物污染产生和建设危险废物集中处置场等。     

酸雨作用下中亚带森林冠层淋溶规律研究

2001年1月～2002年6月对韶山亚热带常绿阔叶林4个采样区进行了酸雨的监测,以监测数据为依据,分析研究了林内穿透水中主要离子的淋溶规律。结果表明:大气降水经过森林冠层后pH值明显升高,韶山亚热带常绿阔叶林对SO42-、NO3-、Mg2+、NH4+离子具有吸收作用,特别是NH4+和NO3-离子。SO42-、Ca2+和Mg2+离子的冠层淋溶百分率随降雨量的增加有明显减少的趋势。Ca2+、K+和Cl-随着pH的增加,其冠层淋溶百分率呈增加趋势。韶山地区在常年酸沉降作用下,森林冠层对酸性离子SO42-、NO3-的吸收作用最强。根据18个月离子浓度平均值来计算,韶山地区森林冠层离子的淋溶序列为:K+>Ca2+>Cl->Mg2+>SO42->NO3->NH4+>Na+。     

市区餐饮娱乐业环境管理浅见

本文从实际出发对市辖区餐饮业这个突出的环境敏感问题，查摆了现象，分析了产生原因，结合现阶段市辖区餐饮业环境管理实际，提出了针对性整改的措施。     

Production of N2O in two biologic nitrogen removal processes: a comparison between conventional and short-cut nitrogen removal processes

The N2O production in two nitrogen removal processes treating domestic wastewater was investigated in laboratory-scale aerobic-anoxic sequencing batch reactors （SBRs）. Results showed that N2O emission happened in the aerobic phase rather than in the anoxic phase. During the aerobic phase, the nitrogen conversion to N2O gas was 27.7% and 36.8% of NH＋-N loss for conventional biologic N-removal process and short-cut biologic N-removal process. The dissolved N2O was reduced to N2 in the anoxic denitrification phase. The N2O production rate increased with the increasing of nitrite concentration and ceased when NH＋-N oxidation was terminated. Higher nitrite accumulation resulted in higher NEO emission in the short-cut nitrogen removal process. Pulse-wise addition of 20 mg NO2 -N. L- 1 gave rise to 3-fold of N2O emission in the conventional N-removal process, while little change happened with 20 mg NOS-N L-1 was added to SBR1.