scholarly journals Organic carbon, nutrient, and salt dynamics in saline soil and switchgrass (Panicum virgatum L.) irrigated with treated municipal wastewater

2017 ◽  
Vol 29 (1) ◽  
pp. 80-90 ◽  
Author(s):  
Girisha Ganjegunte ◽  
April Ulery ◽  
Genhua Niu ◽  
Yanqi Wu
2002 ◽  
Vol 2 (3) ◽  
pp. 235-242 ◽  
Author(s):  
E. Koukouraki ◽  
E. Diamadopoulos

Chlorination batch experiments were conducted in order to estimate the concentration of THM and their formation potential in nitrified and partially nitrified secondary effluent. The role of contact time (up to 2 hours), chlorine dose (3 levels), pH and temperature on the formation of THM was evaluated. THM formation, as measured by individual concentration as well as formation potential, was high for the nitrified secondary effluent, while for the partially nitrified effluent the respective concentrations were low, due to the reaction of chlorine with ammonia to form chloramines. In general, THM concentrations progressively increased as contact time, pH and chlorine dose increased. Increase in temperature (from 15-25°C) showed a rather limited effect. In addition, coagulation tests were applied prior to chlorination of the nitrified effluent for removing organic carbon and thereby controlling the formation of THM. Alum was used as the coagulant in doses varying from 0.1 mM to 2.5 mM. As the coagulant dose increased, the removal of both DOC and absorbance at 254 nm increased, while THM formation decreased. The reduction in THM formation was more pronounced for coagulant doses higher than 1.5 mM.


Land ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 509
Author(s):  
Marek Jarecki ◽  
Kumudinie Kariyapperuma ◽  
Bill Deen ◽  
Jordan Graham ◽  
Amir Behzad Bazrgar ◽  
...  

Warm season perennial C4 grasses (WSGs), switchgrass (Panicum virgatum L.) and miscanthus species (Miscanthus spp.), have been reported to positively influence short-term (15–20 years) soil organic carbon (SOC). In this study, the DayCent model was used to predict changes in long-term SOC stocks under WSGs for moderate (Representative Concentration Pathway (RCP) 4.5) and high (RCP 8.5) warming climate change scenarios in southern Ontario, Canada, and to determine how long the enhanced SOC stock will last when WSGs are converted back to annual crop rotation. The model predicted that a consistent corn–corn–soybean–winter wheat (CCSW) rotation prevented SOC from depletion over the 21st century. Under WSGs, the model predicted high rates of SOC sequestration during the first 20–30 years which then tended to stabilize after 50–60 years. However, the rate of SOC sequestration over 90 years for RCP 4.5 was 0.26 and 0.94 Mg C ha−1 yr−1 for switchgrass and miscanthus, respectively. If 40-year stands of WSGs are converted back to CCSW, the model predicted SOC decline to the previous level in 40–50 years. DayCent predicted that under RCP 8.5 scenario in the second half of the 21st century and in the future, there will be a reduction in SOC stocks, especially under miscanthus stands.


2007 ◽  
Vol 98 (16) ◽  
pp. 2985-2992 ◽  
Author(s):  
Gautam Sarath ◽  
Lisa M. Baird ◽  
Kenneth P. Vogel ◽  
Robert B. Mitchell

2015 ◽  
Vol 72 (4) ◽  
pp. 579-584 ◽  
Author(s):  
A. Muramatsu ◽  
H. Ito ◽  
A. Sasaki ◽  
A. Kajihara ◽  
T. Watanabe

To achieve enhanced nitrogen removal, we modified a cultivation system with circulated irrigation of treated municipal wastewater by using rice for animal feed instead of human consumption. The performance of this modified system was evaluated through a bench-scale experiment by comparing the direction of circulated irrigation (i.e. passing through paddy soil upward and downward). The modified system achieved more than three times higher nitrogen removal (3.2 g) than the system in which rice for human consumption was cultivated. The removal efficiency was higher than 99.5%, regardless of the direction of circulated irrigation. Nitrogen in the treated municipal wastewater was adsorbed by the rice plant in this cultivation system as effectively as chemical fertilizer used in normal paddy fields. Circulated irrigation increased the nitrogen released to the atmosphere, probably due to enhanced denitrification. Neither the circulation of irrigation water nor its direction affected the growth of the rice plant and the yield and quality of harvested rice. The yield of rice harvested in this system did not reach the target value in normal paddy fields. To increase this yield, a larger amount of treated wastewater should be applied to the system, considering the significant amount of nitrogen released to the atmosphere.


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