Investigating the use of the artificial sweetener acesulfame to evaluate septic system inputs and their nutrient loads to streams at the watershed scale

2020 ◽  
Vol 587 ◽  
pp. 124918
Author(s):  
Lauren E. Oldfield ◽  
James W. Roy ◽  
Clare E. Robinson
2002 ◽  
Author(s):  
Jennifer B. Suttles ◽  
George Vellidis ◽  
David Bosch ◽  
Richard Lowrance ◽  
E. Lynn Usery ◽  
...  

2011 ◽  
Vol 64 (9) ◽  
pp. 1767-1773 ◽  
Author(s):  
Wang Xiaoyan ◽  
Lin Qinhui

The objective of this paper is to study the impact of critical source area (CSA) within an Annualized AGricultural Non-Point Source pollution models (AnnAGNPS) simulation at medium- large watershed scale. The impact of CSA on terrain attributes is examined by comparing six sets of CSA (0.5, 1, 2, 4, 6 and 8 km2). The accuracy of AnnAGNPS stimulation on runoff, sediment and nutrient loads on these sets of CSA is further suggested in this paper. The results are as followed: (1) CSA has little effect on watershed area, and terrain altitude. The number of cell and reach decreases with the increase of CSA in power function regression curve. (2) The variation of CSA will lead to the uncertainty of average slope which increase the generalization of land characteristics. At the CSA range of 0.5–1 km2, there is little impact of CSA on slope. (3) Runoff amount does not vary so much with the variation of CSA whereas soil erosion and total nitrogen (TN) load change prominently. An increase of sediment yield is observed firstly then a decrease following later. There is evident decrease of TN load, especially when CSA is bigger than 6 km2. Total phosphorus load has little variation with the change of CSA. Results for Dage watershed show that CSA of 1 km2 is desired to avoid large underestimates of loads. Increasing the CSA beyond this threshold will affect the computed runoff flux but generate prediction errors for nitrogen yields. So the appropriate CSA will control error and make simulation at acceptable level.


2020 ◽  
Vol 10 (18) ◽  
pp. 6525
Author(s):  
Guy Iverson ◽  
Christa Sanderford ◽  
Charles P. Humphrey ◽  
J. Randall Etheridge ◽  
Timothy Kelley

Wastewater contains elevated concentrations of fecal indicator bacteria (FIB). The type of wastewater treatment technology and septic system density may influence the FIB concentration and exports at the watershed scale. The goal of this study was to gain a better understanding of FIB concentrations and exports from watersheds served by conventional septic (CS) systems, sand filter (SF) septic systems, and a municipal sewer (SEW) system. Seven watersheds (3 CS, 3 SF, and 1 SEW) were monitored to quantify FIB concentration and export monthly from April 2015 to March 2016. The type of wastewater treatment did not yield significant differences in FIB concentration or exports when pooling watersheds using similar wastewater treatment. Watersheds with the highest septic densities (approximately 0.4 systems ha−1) contained greater FIB concentrations and exports than watersheds with the lowest (approximately 0.1–0.2 systems ha−1), but only FIB concentrations significantly differed. These findings suggest that when the septic system density exceeds 0.4 systems ha−1, water quality degradation from septic leachate may be observable at the watershed scale, especially in watersheds dominated by residential development. More research is recommended to determine if this density threshold is similar for other water pollutants and/or in watersheds with differing hydrogeological, land use, and wastewater characteristics.


2019 ◽  
Author(s):  
Mujen Wang ◽  
◽  
Catherine M. O'Reilly ◽  
Wondwosen Mekonnen Seyoum ◽  
Shalamar D. Armstrong ◽  
...  

2019 ◽  
Vol 3 (1) ◽  
pp. 1-14
Author(s):  
Philip Brick ◽  
Kent Woodruff

This case explores the Methow Beaver Project (MBP), an ambitious experiment to restore beaver (Castor canadensis) to a high mountain watershed in Washington State, USA. The Pacific Northwest is already experiencing weather regimes consistent with longer term climate projections, which predict longer and drier summers and stronger and wetter winter storms. Ironically, this combination makes imperative more water storage in one of the most heavily dammed regions in the nation. Although the positive role that beaver can play in watershed enhancement has been well known for decades, no project has previously attempted to re-introduce beaver on a watershed scale with a rigorous monitoring protocol designed to document improved water storage and temperature conditions needed for human uses and aquatic species. While the MBP has demonstrated that beaver can be re-introduced on a watershed scale, it has been much more difficult to scientifically demonstrate positive changes in water retention and stream temperature, given hydrologic complexity, unprecedented fire and floods, and the fact that beaver are highly mobile. This case study can help environmental studies students and natural resource policy professionals think about the broader challenges of diffuse, ecosystem services approaches to climate adaptation. Beaver-produced watershed improvements will remain difficult to quantify and verify, and thus will likely remain less attractive to water planners than conventional storage dams. But as climate conditions put additional pressure on such infrastructure, it is worth considering how beaver might be employed to augment watershed storage capacity, even if this capacity is likely to remain at least in part inscrutable.


Author(s):  
Laxman Devkota ◽  
Bhupendra Poudel ◽  
Junu Silwal

The objective of the present study is to develop chewable tablets containing different pharmaceutical compositions with simple manufacturing procedures using different excipients. Mannitols, L-HPC 11, Aspartame, Crospovidone, Crospovidone, Aerosil, and Magnesium Stearate are used as excipients for effective formulation of anti-asthmatic drug Montelukast. Montelukast is a selective, orally acting leukotriene receptor antagonist that is used for the treatment of asthma and seasonal allergic rhinitis. Montelukast chewable tablets were prepared by Direct Compression methods using suitable excipients. The chewable tablets were better presented using artificial sweetener Aspartame as flavouring agent. A total of forteen formulations were prepared and the granules were evaluated for pre-compression parameters. The formulated tablets were evaluated for post-compression parameters .The results showed that all the physical parameters were within the acceptable limits. The in vitro release study of all the formulations showed good release. The study concludes that aforementioned excipients can be used to design chewable montelukast sodium tablets.


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