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Export of nutrients and suspended solids from major Arctic rivers and their response to permafrost degradation

Advances in Climate Change Research 2021年第4期12卷 466-474页

作者： ZHANG Shu-Min MU Cui-Cui LI Zhi-Long DONG Wen-Wen WANG Xing-Yu Irina STRELETSKAYA Valery GREBENETS Sergey SOKRATOV Alexander KIZYAKOV WU Xiao-Dong Key Laboratory of Western China's Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou730000China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519000China Cryosphere Research Station on the Qinghai-Tibetan Plateau State Key Laboratory of Cryospheric ScienceNorthwest Institute of Eco-Environment and ResourceChinese Academy of SciencesLanzhou730000China University Cooperation of Polar Research Beijing100875China Geographical Faculty Lomonosov Moscow State UniversityMoscow119991Russia

The rapid warming of the Arctic has led to permafrost degradation,accelerating the transport of terrestrial materials by *** quan-titative assessment of riverine nutrients and total suspended solids(TSS)flux is important to clarify the land-ocean connections in the ***,much is unknown about the estimates of these components from direct measurements in the Arctic rivers and the response of the components to permafrost ***,we report the results from the Arctic Great Rivers Observatory(Arctic-GRO)for the six major Arctic rivers(Yenisey,Lena,Ob',Mackenzie,Yukon,and Kolyma)to investigate the riverine exports of TSS,total dissolved nitrogen(TDN),nitrate(NO3-),bicarbonate(HCO3-),total dissolved phosphorus(TDP),and phosphate(PO43-).The results showed that from 2004 to 2017,the annual TSS,TDN,and NO3-exports to the Arctic Ocean were approximately 106,026 Gg,692 Gg,and 130 Gg,respectively,and the HCO3-,TDP,and PO43-exports were approximately 79,092 Gg,32 Gg,and 18 Gg,*** were remarkable variations in component concentrations and fluxes between *** than 80%of the TDN,TDP,PO43,and TSS exports mainly occurred in spring and summer,and a high HCO3-flux was recorded in summer,while a high NO3-flux in some rivers occurred in *** active layer thickness was significantly positively correlated with the annual TDN,NO3-,and *** addition,the HCO3-flux of the six Arctic rivers increased by 247 Gg per year during *** positive relationship between the active layer thickness and river discharge indicates that permafrost degradation accelerated rivefine carbonate,nitrogen,and phosphorus *** study demonstrates that riverine exports play an important role both in the Arctic terrestrial and marine ecosystems,and permafrost degradation will likely increase the riverine material exports to the ocean.

关键词： Arctic rivers Carbonate Nutrients total suspended solids Permafrost

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Utilization of Corn Residues for Water Filtration at Fish Tanks

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Journal of Hydraulic Engineering 2016年第1期2卷 13-24页

作者： Al-Rajhi M. A. Ag. Eng. Res. Institute AEnRI ARC. El-Doki Egypt

Filtration has been widely used in re-circulating aquaculture system to remove waste. However, the study of some agricultural residues （corn） usage as the filter medium has not yet been studied. Therefore, the aim of this study is to construct a filter made from inexpensive and readily available corn residues and to analyze its effectiveness in controlling suspended solids that directly impact health of fish through abrasion of gill tissues or indirectly through water quality deterioration. The performance evaluation procedure was carried out in an aquaculture system with production in glass tanks located indoor in laboratory at Faculty of Agriculture, Damietta University, Egypt. The evaluation included three concentrations of total suspended solids （450, 900 and 1,350 mg/L）; four residues particle size distribution （3.35, 9.53, 12.7 mm and ascending order to mentioned sizes from bottom to top）; and four thicknesses of filter layer （9, 21, 33 and 45 cm）. The effectiveness of this filter was measured by determining filter efficiency （ηf）, % and filtration rate （FR）, mL/min. It was observed that the maximum value of （ηf）, % was achieved at 450 mg/L concentration of total suspended solids, ascending order to sizes from bottom to top and 45 cm thickness of filtration layer. The maximum value of filtration rate was achieved at 450 mg/l concentration of total suspended solids, 12.7 mm particle size distribution and 9 cm thickness of filter layer. Results indicated that this filter is efficient enough to remove suspended solids. Therefore, this milled corn residues filter can be used in aquaculture systems for Nile tilapia, Oreochromis niloticus culture system.

关键词： Agricultural residues corn filter re-circulating aquaculture system total suspended solids filtration rate.

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Characterisation of Raw Sewage and Performance Evaluation of Al-Diwaniyah Sewage Treatment Work, Iraq

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World Journal of Engineering and Technology 2016年第2期4卷 296-304页

作者： Hussein Janna Civil Engineering Department Al-Qadisiyah University Al-Diwaniyah Iraq

These days, water and wastewater treatment are one of the most important issues regarding to the human health. Wastewaters are one of the most environmental pollutants and a wide range of adverse effects linked to the effect of untreated wastewaters or wastewaters that treat improperly. The aim of this present study was to evaluate performance of the wastewater treatment plant at Al-Diwaniyah City according to the national standards. Therefore, data of the most common parameters (PH, BOD5, COD, TSS, PO4, NO3, Cl, and Oil and Grease) were collected from the wastewater treatment plant. The study revealed that the wastewater treatment plant was receiving medium to strong influent with a BOD5/COD ratio of between (0.4 - 0.7). Regression analysis was achieved to approximate the influent of BOD5 and TSS. While the effluent quality was exceeded the Iraq standards for disposing treated wastewater to the water bodies with a fluctuation in the ratio of BOD5to COD as a consequence of the operational problems. Therefore, these results would be of help to planners and policy makers in the City to combat such this problem and to take the necessary actions to reduce the impact of these pollutants.

关键词： Biochemical Oxygen Demand total suspended solids Al-Diwaniyah Sewage Treatment Works Activated Sludge Process

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