scholarly journals Nutrient uptake in a simplified stream channel: Experimental manipulation of hydraulic residence time and transient storage

Ecohydrology ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. e2012 ◽  
Author(s):  
Davi Gasparini Fernandes Cunha ◽  
Nícolas Reinaldo Finkler ◽  
Maria do Carmo Calijuri ◽  
Timothy P. Covino ◽  
Flavia Tromboni ◽  
...  
Keyword(s):  
Nutrient Uptake ◽  
Residence Time ◽  
Experimental Manipulation ◽  
Transient Storage ◽  
Stream Channel ◽  
Hydraulic Residence Time

scholarly journals Vegetation and Residence Time Interact to Influence Metabolism and Net Nutrient Uptake in Experimental Agricultural Drainage Systems

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1416
Author(s):  
Rachel L. Nifong ◽  
Jason M. Taylor
Keyword(s):  
Nutrient Uptake ◽  
Residence Time ◽  
Best Management Practices ◽  
Ecosystem Respiration ◽  
N Uptake ◽  
Agricultural Drainage ◽  
Residence Times ◽  
Hydraulic Residence Time ◽  
Uptake Rates ◽  
Lower Mississippi River

Agricultural drainage networks within the Lower Mississippi River Basin (LMRB) have potential to attenuate nutrient loading to downstream aquatic ecosystems through best management practices. Nutrient uptake (nitrogen, phosphorus), gross primary production (GPP), ecosystem respiration (ER), and denitrification rates were estimated using a combination of sensor measurements and hourly discrete samples for dissolved nutrients and gases at three hydraulic residence times (2, 4, and 6 h) in three vegetated and three unvegetated ditches. We also measured vegetation and soil nutrient content. GPP and ER were significantly higher in vegetated drainages and increasing hydraulic residence time increased respiration rates. Shorter hydraulic residence times were associated with increased uptake rates for both N and P, and vegetation increased N uptake rates in all hydraulic residence time (HRT) treatments. Vegetation and sediment assimilated N and P over the course of the experiment. Overall, our experimental results demonstrate the strong role of emergent vegetation in nutrient retention and removal processes in agricultural drainage ditch networks.

Impact of hydraulic residence time on nitrate removal in pilot-scale woodchip bioreactors

2019 ◽  
Vol 237 ◽  
pp. 424-432 ◽  
Author(s):  
E.A. Martin ◽  
M.P. Davis ◽  
T.B. Moorman ◽  
T.M. Isenhart ◽  
M.L. Soupir
Keyword(s):  
Residence Time ◽  
Nitrate Removal ◽  
Pilot Scale ◽  
Hydraulic Residence Time

Transformation of a Petroleum Mixture in Biofilms

1992 ◽  
Vol 26 (3-4) ◽  
pp. 637-646 ◽  
Author(s):  
E. J. Bouwer ◽  
C. T. Chen ◽  
Y.-H. Li
Keyword(s):  
Residence Time ◽  
Petroleum Hydrocarbons ◽  
Reaction Rates ◽  
Hydrocarbon Contamination ◽  
Waste Oil ◽  
Column Studies ◽  
Hydraulic Residence Time ◽  
Methyl Naphthalene ◽  
Aerobic And Anaerobic ◽  
Underlying Soil

Petroleum hydrocarbons from a lagoon storing waste oil in New Jersey have contaminated underlying soil and groundwater. Biofilm column studies were performed to investigate biotransformation of the petroleum mixture under aerobic and anaerobic conditions. The waste oil at concentrations ranging between 10 and 100 mg/L was continuously applied to glass bead columns that resembled porous media. The majority of the alkylbenzenes and polynuclear aromatic compounds identified in the oil mixture were simultaneously biotransformed by aerobic biofilms within a 2-hour hydraulic residence time. In a methanogenic biofilm column with 2-day hydraulic residence time, the mixture of hydrocarbons was initially removed by sorption with complete breakthrough occurring after 300 days of operation. After 600 days, the methanogenic biofilm acclimated to several of the specific hydrocarbon components, and effluent concentrations decreased due to apparent biotransformation. Radiotracer studies with toluene, naphthalene, and 2-methyl-naphthalene indicated partial mineralization to CO2 under both aerobic and methanogenic conditions. Reaction rates observed in the laboratory biofilms indicate that biotransformation could be an effective process to control hydrocarbon contamination in the environment.

scholarly journals Assessment of a low-cost, point-of-use, ultraviolet water disinfection technology

2007 ◽  
Vol 6 (1) ◽  
pp. 53-65 ◽  
Author(s):  
Sarah A. Brownell ◽  
Alicia R. Chakrabarti ◽  
Forest M. Kaser ◽  
Lloyd G. Connelly ◽  
Rachel L. Peletz ◽  
...  
Keyword(s):  
Rural Communities ◽  
Residence Time ◽  
Low Cost ◽  
Plug Flow ◽  
Field Studies ◽  
Water Disinfection ◽  
Galvanized Steel ◽  
Hydraulic Residence Time ◽  
Biological Assays ◽  
Point Of Use

We describe a point-of-use (POU) ultraviolet (UV) disinfection technology, the UV Tube, which can be made with locally available resources around the world for under $50 US. Laboratory and field studies were conducted to characterize the UV Tube's performance when treating a flowrate of 5 L/min. Based on biological assays with MS2 coliphage, the UV Tube delivered an average fluence of 900±80 J/m2 (95% CI) in water with an absorption coefficient of 0.01 cm−1. The residence time distribution in the UV Tube was characterized as plug flow with dispersion (Peclet Number = 19.7) and a mean hydraulic residence time of 36 s. Undesirable compounds were leached or produced from UV Tubes constructed with unlined ABS, PVC, or a galvanized steel liner. Lining the PVC pipe with stainless steel, however, prevented production of regulated halogenated organics. A small field study in two rural communities in Baja California Sur demonstrated that the UV Tube reduced E. coli concentrations to less than 1/100 ml in 65 out of 70 samples. Based on these results, we conclude that the UV Tube is a promising technology for treating household drinking water at the point of use.

Ballast Waters Treatment Using UV/(H2O2+O3) Advanced Oxidation Process with Heterosigma akashiwo, Pyramimimonas sp., and Escherichia coli as Indicator Microorganism

2013 ◽  
Vol 663 ◽  
pp. 946-952
Author(s):  
Hong Huang ◽  
Hua Feng Yu ◽  
Guang Ming Liu
Keyword(s):  
Escherichia Coli ◽  
Water Treatment ◽  
Residence Time ◽  
Ballast Water ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Advanced Oxidation ◽  
Hydraulic Residence Time ◽  
Ballast Water Treatment ◽  
Inactivation Efficiency

Introducing invasive species through ballast water is a specific pollution problem and has recently identified as one of the main concerns of Maritime Organizations. UV/(H2O2/O3) advanced oxidation process is a technological alternative to prevent this maritime pollution. In this present study, inactivation efficiency of the UV/(H2O2/O3) processes for ballast water treatment using Heterosigma akashiwo, Pyramimimonas sp. and Escherichia coli as indicator microorganisms was investigated. Compared with individual or combined two units processes using UV, H2O2 and O3, the UV/(H2O2+O3) process yield the highest levels of inactivation due to synergistic effects. In order to study the dynamic inactivation efficiency of equipment for stimulated ballast water treatment, the effects tests of the hydraulic residence time were conducted. The results indicated that the shorter hydraulic residence time had better inactivation efficiency. These findings have implications for the ballast water treatment.

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