Nitrogen removal in micro-polluted surface water by the combined process of bio-filter and ecological gravel bed

2013 ◽  
Vol 67 (10) ◽  
pp. 2356-2362 ◽  
Author(s):  
He Sheng-bing ◽  
Gao Jian-wen ◽  
Chen Xue-chu ◽  
Dai Ding-li
Keyword(s):  
Surface Water ◽  
Carbon Source ◽  
Water Temperature ◽  
Nitrogen Removal ◽  
Significant Influence ◽  
Sodium Acetate ◽  
Denitrification Rate ◽  
Combined Process ◽  
Gravel Bed ◽  
Hydraulic Load

Nitrogen removal in micro-polluted surface water by the combined process of a bio-filter and an ecological gravel bed was studied. Sodium acetate was added into micro-polluted surface water as carbon source and the nitrogen removal under different C/N ratio, hydraulic load and temperature were investigated. The results showed that the variations in C/N ratio, hydraulic load and temperature have significant influence on nitrogen removal in bio-filter. It was found that the denitrification rate was above 90% when C/N ratio reached 10; also, the denitrification was inhibited at low water temperature (2–10 °C); at the condition of water temperature above 20 °C, C/N ratio 10, hydraulic load 8 m3/(m2 h), the combined process obtained the nitrogen removal of more than 90%, and the residual organics could be removed in ecological gravel bed.

Effects of influent COD/N ratio and internal recycle ratio on nitrogen removal efficiency in the KNR process

2006 ◽  
Vol 53 (9) ◽  
pp. 265-270 ◽  
Author(s):  
C.W. Suh ◽  
S.H. Lee ◽  
H.S. Jeong ◽  
J.C. Kwon ◽  
H.S. Shin
Keyword(s):  
Carbon Source ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Denitrification Rate ◽  
Optimal Operating ◽  
Operating Condition ◽  
Optimal Operating Condition ◽  
External Carbon Source ◽  
Recycle Ratio ◽  
Removal Efficiencies

In this study, with the KNR® process that has many advantages, the nitrogen removal efficiency of KNR was experimentally investigated at various COD/N ratios of influent conditions. The optimal operating condition of internal recycle ratio was evaluated. The TN removal efficiencies were 59.1, 72.5 and 75.9% at the COD/N ratios of 3, 5 and 7, respectively. These high removal efficiencies resulted from high denitrification rate in UMBR with high microorganism concentration. Furthermore, specific endogenous denitrification at MLVSS of 10.3 g/L that is similar to MLVSS in UMBR was over two times higher than that at MLVSS of 2.06 g/L. This result suggests that endogenous denitrification rate in UMBR is so high that the requirement of an external carbon source can be saved. As the internal recycle ratio increased from 100 to 400%, the TN removal efficiency also improved from 69.5 to 82.9%, and the optimal internal recycle ratio was 300%.

Study on Biological Nitrogen Removal Performance of Aerobic Denitrification Treating Power Plant Wastewater

2013 ◽  
Vol 726-731 ◽  
pp. 2589-2593
Author(s):  
Tao Yang ◽  
Pei Ying Wu ◽  
Zhan Sheng Zhao ◽  
Hua Wei Xu ◽  
Gao Zhi Lv
Keyword(s):  
Power Plant ◽  
Carbon Source ◽  
Organic Carbon ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Sodium Acetate ◽  
Aerobic Denitrification ◽  
Biological Nitrogen Removal ◽  
Organic Carbon Source ◽  
Biological Nitrogen

Enriched domestication in SBR was used to improve the proportion of aerobic denitrifiers in activated sludge, and actual power plant wastewater was treated, which proved the existence of aerobic denitrification. But at the later stage, because of carbon deficiency, aerobic denitrifiers were inhibited and NO3--N accumulated. Sodium acetate used as external organic carbon source was added when reaction carried on 3.5 hours to improve the COD/NH4+-N ratio from 6.5 to 10, effluent NO3--N concentration was 3.6 mg\L, average removal efficiency of TN was 90%, which could improve the aerobic denitrification performance of whole system effectively.

Nitrogen removal efficiency and capacity in biofilms with biologically hydrolysed sludge as a carbon source

1994 ◽  
Vol 30 (6) ◽  
pp. 63-71 ◽  
Author(s):  
A. Æsøy ◽  
H. Ødegaard
Keyword(s):  
Fatty Acids ◽  
Organic Matter ◽  
Carbon Source ◽  
Nitrogen Removal ◽  
Volatile Fatty Acids ◽  
Denitrification Rate ◽  
Diffusion Resistance ◽  
Soluble Organic Matter ◽  
Biological Sludge ◽  
Sludge Hydrolysis

The possibility of using biologically hydrolysed sludge as carbon source for the denitrification process in biofilms has been investigated. The goal of the biological sludge hydrolysis process is a high degree of solubilization of the organic matter in the sludge. The soluble organic matter is best dominated by readily biodegradable compounds. The biological hydrolysis of chemical/biological raw sludge resulted in a degree of solubilization (yield) of 11%, where about 84% of the soluble organic matter originated from protein materials. The solubilized nitrogen was found as ammonium-nitrogen. The sludge was composed of 70% chemical sludge and 30% biological sludge. On average 66% of the soluble organic matter was volatile fatty acids. Only the volatile fatty acids were utilized as carbon source in the denitrifying biofilm. The biofilms were around 1000 μm thick, and the denitrification rate with respect to the concentration of volatile fatty acids could be described by a hyperbolic Monod-type function. The effect of the diffusion resistance in the biofilms was reflected by the use of an artificial “half-saturation” constant, K*CODVFA = 3 mg CODVFA/l. The maximum denitrification rate was found to be rmaxNO3-N = 0.57 g NO3-N/g VS· d. The stoichiometric consumption ratio between soluble organic matter and nitrate was 4.5 g CODVFA/g NO3-N on average. A simulation example on the nitrogen removal capacity when the carbon source is provided by sludge hydrolysis is given.

Pre-Precipitation Facilitates Nitrogen Removal without Tank Expansion

1990 ◽  
Vol 22 (7-8) ◽  
pp. 85-92 ◽  
Author(s):  
Ingemar Karlsson ◽  
Gunnar Smith
Keyword(s):  
Waste Water ◽  
Organic Matter ◽  
Water Treatment ◽  
Carbon Source ◽  
Nitrogen Removal ◽  
Waste Water Treatment ◽  
Chemical Precipitation ◽  
Sewage Water ◽  
Laboratory Studies ◽  
Denitrification Process

Chemically coagulated sewage water gives an effluent low in both suspended matter and organics. To use chemical precipitation as the first step in waste water treatment improves nitrification in the following biological stage. The precipitated sludge contains 75% of the organic matter in the sewage and can by hydrolysis be converted to readily degradable organic matter, which presents a valuable carbon source for the denitrification process. This paper will review experiences from full-scale applications as well as pilot-plant and laboratory studies.

scholarly journals Surface Water Temperature Predictions at a Mid-Latitude Reservoir under Long-Term Climate Change Impacts Using a Deep Neural Network Coupled with a Transfer Learning Approach

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1109
Author(s):  
Nobuaki Kimura ◽  
Kei Ishida ◽  
Daichi Baba
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
Water Temperature ◽  
Transfer Learning ◽  
Air Temperature ◽  
Climate Models ◽  
Temporal Variations ◽  
Training Data ◽  
Surface Water Temperature

Long-term climate change may strongly affect the aquatic environment in mid-latitude water resources. In particular, it can be demonstrated that temporal variations in surface water temperature in a reservoir have strong responses to air temperature. We adopted deep neural networks (DNNs) to understand the long-term relationships between air temperature and surface water temperature, because DNNs can easily deal with nonlinear data, including uncertainties, that are obtained in complicated climate and aquatic systems. In general, DNNs cannot appropriately predict unexperienced data (i.e., out-of-range training data), such as future water temperature. To improve this limitation, our idea is to introduce a transfer learning (TL) approach. The observed data were used to train a DNN-based model. Continuous data (i.e., air temperature) ranging over 150 years to pre-training to climate change, which were obtained from climate models and include a downscaling model, were used to predict past and future surface water temperatures in the reservoir. The results showed that the DNN-based model with the TL approach was able to approximately predict based on the difference between past and future air temperatures. The model suggested that the occurrences in the highest water temperature increased, and the occurrences in the lowest water temperature decreased in the future predictions.

Impact of climate warming on the surface water temperature of plateau lake

2021 ◽  
Author(s):  
Zongqi Peng ◽  
Jiaying Yang ◽  
Yi Luo ◽  
Kun Yang ◽  
Chunxue Shang
Keyword(s):  
Surface Water ◽  
Water Temperature ◽  
Climate Warming ◽  
Surface Water Temperature ◽  
Plateau Lake

scholarly journals Seasonal Succession of Bacterial Communities in Three Eutrophic Freshwater Lakes

2021 ◽  
Vol 18 (13) ◽  
pp. 6950
Author(s):  
Bin Ji ◽  
Cheng Liu ◽  
Jiechao Liang ◽  
Jian Wang
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Water Temperature ◽  
Bacterial Communities ◽  
Seasonal Succession ◽  
Lake Eutrophication ◽  
Urban Lake ◽  
Freshwater Lakes ◽  
Functional Prediction ◽  
Bacterial Indicator

Urban freshwater lakes play an indispensable role in maintaining the urban environment and are suffering great threats of eutrophication. Until now, little has been known about the seasonal bacterial communities of the surface water of adjacent freshwater urban lakes. This study reported the bacterial communities of three adjacent freshwater lakes (i.e., Tangxun Lake, Yezhi Lake and Nan Lake) during the alternation of seasons. Nan Lake had the best water quality among the three lakes as reflected by the bacterial eutrophic index (BEI), bacterial indicator (Luteolibacter) and functional prediction analysis. It was found that Alphaproteobacteria had the lowest abundance in summer and the highest abundance in winter. Bacteroidetes had the lowest abundance in winter, while Planctomycetes had the highest abundance in summer. N/P ratio appeared to have some relationships with eutrophication. Tangxun Lake and Nan Lake with higher average N/P ratios (e.g., N/P = 20) tended to have a higher BEI in summer at a water temperature of 27 °C, while Yezhi Lake with a relatively lower average N/P ratio (e.g., N/P = 14) tended to have a higher BEI in spring and autumn at a water temperature of 9–20 °C. BEI and water temperature were identified as the key parameters in determining the bacterial communities of lake water. Phosphorus seemed to have slightly more impact on the bacterial communities than nitrogen. It is expected that this study will help to gain more knowledge on urban lake eutrophication.

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