A mass balance study on nitrification and deammonification in vertical flow constructed wetlands treating landfill leachate

2007 ◽  
Vol 56 (3) ◽  
pp. 117-123 ◽  
Author(s):  
G. Sun ◽  
D. Austin
Keyword(s):  
Mass Balance ◽  
Total Nitrogen ◽  
Landfill Leachate ◽  
Nitrogen Loss ◽  
Organic Content ◽  
Vertical Flow ◽  
Ammoniacal Nitrogen ◽  
High Concentration ◽  
Balance Study ◽  
Mass Balance Study

A laboratory-scale, mass-balance study was carried out on the transformation of nitrogenous pollutants in four vertical flow wetland columns. Landfill leachate containing low organic matter, but a high concentration of ammoniacal-nitrogen, was treated under dissolved oxygen concentrations close to saturation. Influent total nitrogen (TN) comprised ammoniacal-nitrogen with less than 1% nitrate and nitrite, negligible organic nitrogen, and very low BOD. Nitrification occurred in three of the four columns. There was a substantial loss of total nitrogen (52%) in one column, whereas other columns exhibited zero to minor losses (<12%). Nitrogen loss under study conditions was unexpected. Two hypotheses are proposed to account for it: (1) either the loss of TN is attributed to nitrogen transformation into a form (provisionally termed α-nitrogen) that is undetectable by the analytical methods used; or (2) the loss is caused by microbial denitrification or deammonification. By elimination and stoichiometric mass balance calculations, completely autotrophic nitrogen-removal over nitrite (CANON) deammonification is confirmed as responsible for nitrogen loss in one column. This result reveals that CANON can be native to aerobic engineered wetland systems treating high ammonia, low organic content wastewater.

scholarly journals Mobilization and Redistribution of Elements in Laterites of Semail Ophiolite, Oman: A Mass Balance Study

2015 ◽  
Vol 20 (1) ◽  
pp. 39 ◽  
Author(s):  
Salah Al Khirbash ◽  
Khadija Semhi
Keyword(s):  
Mass Balance ◽  
High Concentration ◽  
Balance Study ◽  
Geochemical Composition ◽  
Weathering Processes ◽  
Large Fluctuations ◽  
Significant Enrichment ◽  
Mass Balance Study ◽  
Semail Ophiolite ◽  
Elemental Mass

Several samples of laterites were collected from four paleosol profiles, Ibra, East Ibra, Al-Russayl, and Tiwi representing the vertical lithological variation within each profile. The mineralogical and geochemical composition of laterites in every section revealed differences in thickness and redistribution of elements reflecting different conditions of weathering processes. Elemental mass balance was calculated for every profile relative to the parent rock. The results indicated redistribution of elements from the surface to deeper zones with an enrichment of elements in the saprolite and oxide zones. Among the different sections, the profile of East Ibra composite 1 and 2 is characterized by high concentration of all elements compared to the other profiles. Sc/Fe ratio in different zones indicates low values for the profile of Tiwi profile 1, Ibra profile and Al-Russayl composite 2 and 3 profile due to the significant enrichment of Fe in these zones independently of redox conditions. Large fluctuations characterize Th/U ratios and reflect redox condition more reduced in Tiwi area than in East Ibra and Al-Russayl areas.  

scholarly journals Treatment of Leachate Using Up-Flow Anaerobic Sludge Blanket Reactors/Vertical Flow Subsurface Constructed Wetlands

2020 ◽  
Vol 27 (1) ◽  
pp. 129-137
Author(s):  
Şevket Tulun
Keyword(s):  
Total Nitrogen ◽  
Landfill Leachate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Organic Content ◽  
Ammonia Removal ◽  
Anaerobic Sludge ◽  
Vertical Flow ◽  
Physico Chemical ◽  
Anaerobic Sludge Blanket

AbstractThe composition of local solid waste consists mainly of biodegradable waste with high moisture and organic content. After being landfilled, the waste decomposes through a series of combined physico-chemical and biological processes, resulting in the generation of landfill leachate. Unless treated properly, the leachate poses a serious threat to the environment and to public health. In this study, the use of an engineered system consisting of an up-flow anaerobic sludge blanket reactor and a vertical flow subsurface constructed wetland for the treatment of landfill leachate was investigated. The leachate obtained from a landfill facility in Aksaray, Turkey was fed into both systems and laboratory tests showed that, over the 6-week study period, the systems were able to efficiently remove chemical oxygen demand (88.6 %) and total nitrogen (80.7 %). The results of this study suggested that Typha angustifolia significantly increased the removal of total nitrogen. The higher ammonia removal occurred in the anaerobic system and also the removal efficiency increased in planted bed, it is presumed to be the result of the ammonia nitrogen uptake by the roots of the plant.

A 90-day oral (dietary) toxicity and mass balance study of corn starch fiber in Sprague Dawley rats

2016 ◽  
Vol 97 ◽  
pp. 57-69 ◽  
Author(s):  
Christine M. Crincoli ◽  
Andrey I. Nikiforov ◽  
Marisa O. Rihner ◽  
Elizabeth A. Lambert ◽  
Melanie A. Greeley ◽  
...  
Keyword(s):  
Mass Balance ◽  
Corn Starch ◽  
Sprague Dawley ◽  
Balance Study ◽  
Sprague Dawley Rats ◽  
Dietary Toxicity ◽  
Mass Balance Study

Unequal Absorption of Radiolabeled and Nonradiolabeled Drug from the Oral Dose Leads to Incorrect Estimates of Drug Absorption and Circulating Metabolites in a Mass Balance Study

2019 ◽  
Vol 13 (1) ◽  
pp. 37-44
Author(s):  
Ryan H. Takahashi ◽  
Jae H. Chang ◽  
Jodie Pang ◽  
Xiaorong Liang ◽  
Shuguang Ma
Keyword(s):  
Oral Dose ◽  
Mass Balance ◽  
Specific Activity ◽  
The Body ◽  
Total Drug ◽  
Beagle Dogs ◽  
Balance Study ◽  
Drug Concentrations ◽  
Specific Activities ◽  
Mass Balance Study

Background: Mass balance studies conducted using radiolabeled material (14C or 3H) definitively characterize the Absorption, Metabolism, and Excretion (AME) of a drug. A critical aspect of these studies is that the radiotracer maintains its proportion to total drug from its administration to its complete elimination from the body. In the study of GDC-0276 in beagle dogs, we observed that the 14C radiotracer proportion (specific activity) varied through the study. Method: High resolution-accurate mass spectrometric measurements of 12C and 14C isotopes of GDC- 0276 and its metabolites in plasma and excreta samples were used to determine the apparent specific activities, which were higher than the specific activity of the dosing formulation. Drug concentrations were adjusted to the observed specific activities to correct the readouts for GDC-0276 AME and PK. Results: The enrichment of 14C, which resulted in higher specific activities, was consistent with faster and more extensive absorption of the radiotracer from the dosing formulation. This resulted in overestimating the dose absorbed, the extent of elimination in urine and bile, and the exposures to circulating metabolites. These biases were corrected by the specific activities determined for study samples by mass spectrometry. Conclusion: Assuming that the radiotracer was proportional to total drug throughout a radiolabeled study was not valid in a 14C study in beagle dogs. This presumably resulted from unequal absorption of the radiotracer and nonradiolabeled test articles from the oral dose due to inequivalent solid forms. We were able to provide a more accurate description of the AME of GDC-0276 in dogs by characterizing the differential absorption of the radiotracer.

A Phase 1 Mass Balance Study of 14 C‐Labeled Talazoparib in Patients With Advanced Solid Tumors

2019 ◽  
Author(s):  
Yanke Yu ◽  
Chin‐Hee Chung ◽  
Anna Plotka ◽  
Kevin Quinn ◽  
Haihong Shi ◽  
...  
Keyword(s):  
Mass Balance ◽  
Solid Tumors ◽  
Phase 1 ◽  
Advanced Solid Tumors ◽  
Balance Study ◽  
Mass Balance Study
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