scholarly journals Greenhouse Gas Emissions From a Horizontal Subsurface Flow Constructed Wetland for Wastewater Treatment in Small Villages

2020 ◽  

<p>Constructed wetlands with a land-intensive, low energy and less operational requirement have been used as a sustainable green technology for treating wastewaters. But are constructed wetlands sustainable? The objectives of the present study are to evaluate one year monitored horizontal subsurface flow constructed wetland’s treatment efficiency from May 2017 to May 2018 and to estimate the greenhouse gas emissions (GHG) in terms of N2O and CH4. As field data show the average removal efficiencies are low but are all within the effluent standard for water quality. One year average of high suspended solids (91.1 %), high total nitrogen (%85.6), low total phosphorous (22.4% TP), low organic matter (43.1% BOD5 &amp; 35.9% COD) removals are obtained. One year average methane and nitrous oxide emissions at the outlet of constructed wetland are calculated as 17.52 and 0.29 kg/d, respectively.</p>

2007 ◽  
Vol 56 (3) ◽  
pp. 49-55 ◽  
Author(s):  
P. Gui ◽  
R. Inamori ◽  
M. Matsumura ◽  
Y. Inamori

Domestic wastewater is a significant source of nitrogen and phosphorus, which cause lake eutrophication. Among the wastewater treatment technologies, constructed wetlands are a promising low-cost means of treating point and diffuse sources of domestic wastewater in rural areas. However, the sustainable operation of constructed wetland treatment systems depends upon a high rate conversion of organic and nitrogenous loading into their metabolic gaseous end products, such as N2O and CH4. In this study, we examined and compared the performance of three typical types of constructed wetlands: Free Water Surface (FWS), Subsurface Flow (SF) and Vertical Flow (VF) wetlands. Pollutant removal efficiency and N2O and CH4 emissions were assessed as measures of performance. We found that the pollutant removal rates and gas emissions measured in the wetlands exhibited clear seasonal changes, and these changes were closely associated with plant growth. VF wetlands exhibited stable removal of organic pollutants and NH3-N throughout the experiment regardless of season and showed great potential for CH4 adsorption. SF wetlands showed preferable T-N removal performance and a lower risk of greenhouse gas emissions than FWS wetlands. Soil oxidation reduction potential (ORP) analysis revealed that water flow structure and plant growth influenced constructed wetland oxygen transfer, and these variations resulted in seasonal changes of ORP distribution inside wetlands that were accompanied by fluctuations in pollutant removal and greenhouse gas emissions.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xue Hao ◽  
Yu Ruihong ◽  
Zhang Zhuangzhuang ◽  
Qi Zhen ◽  
Lu Xixi ◽  
...  

AbstractGreenhouse gas (GHG) emissions from rivers and lakes have been shown to significantly contribute to global carbon and nitrogen cycling. In spatiotemporal-variable and human-impacted rivers in the grassland region, simultaneous carbon dioxide, methane and nitrous oxide emissions and their relationships under the different land use types are poorly documented. This research estimated greenhouse gas (CO2, CH4, N2O) emissions in the Xilin River of Inner Mongolia of China using direct measurements from 18 field campaigns under seven land use type (such as swamp, sand land, grassland, pond, reservoir, lake, waste water) conducted in 2018. The results showed that CO2 emissions were higher in June and August, mainly affected by pH and DO. Emissions of CH4 and N2O were higher in October, which were influenced by TN and TP. According to global warming potential, CO2 emissions accounted for 63.35% of the three GHG emissions, and CH4 and N2O emissions accounted for 35.98% and 0.66% in the Xilin river, respectively. Under the influence of different degrees of human-impact, the amount of CO2 emissions in the sand land type was very high, however, CH4 emissions and N2O emissions were very high in the artificial pond and the wastewater, respectively. For natural river, the greenhouse gas emissions from the reservoir and sand land were both low. The Xilin river was observed to be a source of carbon dioxide and methane, and the lake was a sink for nitrous oxide.


2013 ◽  
Vol 67 (6) ◽  
pp. 1370-1379 ◽  
Author(s):  
J. Liebetrau ◽  
T. Reinelt ◽  
J. Clemens ◽  
C. Hafermann ◽  
J. Friehe ◽  
...  

With the increasing number of biogas plants in Germany the necessity for an exact determination of the actual effect on the greenhouse gas emissions related to the energy production gains importance. Hitherto the life cycle assessments have been based on estimations of emissions of biogas plants. The lack of actual emission evaluations has been addressed within a project from which the selected results are presented here. The data presented here have been obtained during a survey in which 10 biogas plants were analysed within two measurement periods each. As the major methane emission sources the open storage of digestates ranging from 0.22 to 11.2% of the methane utilized and the exhaust of the co-generation units ranging from 0.40 to 3.28% have been identified. Relevant ammonia emissions have been detected from the open digestate storage. The main source of nitrous oxide emissions was the co-generation unit. Regarding the potential of measures to reduce emissions it is highly recommended to focus on the digestate storage and the exhaust of the co-generation.


Sign in / Sign up

Export Citation Format

Share Document