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Landfill leachate concentrates is the waste solution trapped by nanofiltration/reverse osmosis (NF/RO) membrane in the biochemical effluent of landfill leachate. It has high content of salt and dissolved organic matter (DOM), especially refractory organic matter. Electrochemical oxidation of landfill leachate concentrates on Ti/RuO2-Ir/O2 anode, the electrolysis time and current density and plate distances was studied on the effects of the oxidation results. The results showed that, under the optimal conditions with initial pH value 7.8, current density 8 A/dm2, plate distances 1 cm, and electrolysis time 4 h, the chroma, COD, ammonia nitrogen and Cl- removal rates were 100%, 100%, 98% and 52%respectively. UV-vis spectrum analysis showed that the aromatization degree and relative molecular mass and polymerization degree decreased of DOM in the landfill leachate concentrates after electrolysis treatment. 3D-excitation emission matrix fluorescence spectra (3D-EEMFS) showed that humic acid was oxidized to humic acid with simpler structure and smaller relative molecular mass and soluble microbial degradation by-products in the landfill leachate concentrates after electrolysis treatment. FTIR analysis showed that the absorption intensity of organic compounds in the landfill leachate concentrates decreased and most organic compounds were oxidized and degraded after electrolysis treatment. [ABSTRACT FROM AUTHOR]

The safety of the direct reuse of the sludge water and the economic benefits of the direct reuse of the sludge water are analyzed by testing the conventional (e.g. pH, turbidity and NH3-N), organic matter (e.g. CODMn and UV254) and metal indicators (e.g. Al, Fe and Mn) of effluent water quality after the direct reuse of the sludge discharged from the sedimentation tank and by using Zeta potential and particle size distribution analysis. Results show that the direct reuse of the sludge water can enhance the effect of coagulation, that is, after reuse, CODMn will not exceed the standard and has a good removal effect. However, it has minimal effect on UV254 and will not change the classification of soluble substances in raw water. The turbidity, NH3-N, Al, Fe, and Mn of the after-sedimentation water all meet the effluent quality standards under an appropriate reflux ratio. Under controlled reflux ratio conditions, the sludge water can be reused directly, thereby not only saving water resources and bringing economic benefits to the water plant but also protecting the environment to achieve the environmental protection, energy conservation and emission reduction. [ABSTRACT FROM AUTHOR]

Sediments and overlying water were collected from 12 conventional lake sites and 5 conventional estuary sites to study the distribution and influencing factors of various nitrogen forms in sediments of different areas of Poyang Lake during the dry season. The sediment nitrogen is divided into ion-exchangeable nitrogen (IEF-N), weak acid-extractable nitrogen (WAEF-N), strong alkaline-extractable nitrogen (SAEF-N), strong oxidant-extractable nitrogen (SOEF-N) and non-transformable (NTN) by sequential extraction methods. Redundancy analysis and Pearson correlation coefficient are used to study the relationship between the physicochemical properties of sediment and overlying water and the various nitrogen forms. Results show that the sediment total nitrogen (TN) content is 480.79-3933.00 mg/kg, with a mean value of 2441.82 mg/kg, of which transformable nitrogen (TTN) accounts for 24.77% of TN. The contents of each TTN are in the order of SAEF-N > IEF-N > WAEF-N > SOEF-N. Except WAEF-N and SOEF-N, the distribution of IEF-N and SAEF-N is consistent with that of TN, which is in the order of central lake > northern lake > estuary. The distribution of nitrogen forms in the sediments is significantly influenced by the physicochemical properties of overlying water and sediments in Poyang Lake in winter, especially the DO and Chl-a in the overlying water, and TP and Chl-a in sediments. [ABSTRACT FROM AUTHOR]

In order to explore the variation law of pollutants in different underlying surfaces with time, a university in Nanchang was selected as the research area. Four types of underlying surfaces in this university, namely, the main road of the whole school, the main road of the student dormitory area, school leisure square and student dormitory roof, were selected for analysis. Under the circumstance of a single rainfall, the variation law of Suspended Solids (SS), Chemical Oxygen Demand (COD), Total Nitrogen (TN) and Total Phosphorus (TP) pollutants in the four aforementioned underlying surfaces with rainfall time was analyzed to figure out the variation process of pollutants with rainfall duration. The results have shown that the variation range and variation law of water quality were different for varied underlying surfaces and rainfalls. The pollutant concentration of rainfall runoff on the whole showed an attenuation trend, and the attenuation rate was fast in the early stage and became slower in the late stage. Finally, the main pollutants in rainfall runoff of four different underlying surfaces were obtained via analysis. [ABSTRACT FROM AUTHOR]