Non-steady variations of SOD and phosphate release rate due to changes in the quality of the overlying water

2000 ◽  
Vol 42 (3-4) ◽  
pp. 265-272 ◽  
Author(s):  
T. Inoue ◽  
Y. Nakamura ◽  
Y. Adachi
Keyword(s):  
Release Rate ◽  
Oxygen Demand ◽  
Phosphate Concentration ◽  
Sediment Oxygen Demand ◽  
Biochemical Reactions ◽  
Overlying Water ◽  
Phosphate Release ◽  
Do Concentration ◽  
The Difference

A dynamic model, which predicts non-steady variations in the sediment oxygen demand (SOD) and phosphate release rate, has been designed. This theoretical model consists of three diffusion equations with biochemical reactions for dissolved oxygen (DO), phosphate and ferrous iron. According to this model, step changes in the DO concentration and flow velocity produce drastic changes in the SOD and phosphate release rate within 10 minutes. The vigorous response of the SOD and phosphate release rate is caused by the difference in the time scale of diffusion in the water boundary layer and that of the biochemical reactions in the sediment. Secondly, a negative phosphate transfer from water to sediment can even occur under aerobic conditions. This is caused by the decrease in phosphate concentration in the aerobic layer due to adsorption.

Fecal and Coliform Levels as Indicative Factors in Deterioration of the Water Quality of

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
EUKENE OPORTO BENSIG ◽  
MARY JOYCE L. FLORES ◽  
FLEURDELIZ F. MAGLANGIT
Keyword(s):  
Water Quality ◽  
Surface Waters ◽  
Physicochemical Parameters ◽  
Oxygen Demand ◽  
Aquatic Ecology ◽  
Total Dissolved Solids ◽  
Biological Oxygen Demand ◽  
Indicator Bacteria ◽  
The Difference

The use of surface waters such as rivers for domestic, agricultural andindustrial purposes have made them vulnerable to pollution leading to impairedwater quality. The water quality of Lahug River in Cebu City was evaluated usingcoliforms as indicators, in relation with physicochemical parameters such as biological oxygen demand (BOD), conductivity, dissolved oxygen (DO), nitrate,pH, phosphate, salinity, temperature, total dissolved solids (TDS) and totalsuspended solids (TSS). Sampling was done once a month from November 2011to April 2012 in three stations covering the upstream, midstream and downstream.The multiple tube fermentation technique was used for the analysis of coliforms.The level of these indicator bacteria increased from the upstream towards thelower reaches of the river especially in the months of February to April; however,the difference in values across time was not significant. This implies that therewas a continuous fecal pollution in the river. There were no statistically significantcorrelations between FCs and TCs with the physicochemical parameters. Anegative relationship was observed among FCs and TCs with pH, TSS, DOand nitrate (p>0.05). These results suggest the presence of sewage and organicpollutants in the river.Keywords: Aquatic Ecology, water quality, coliform, physicochemical parameters,experimental design, Philippines

A theoretical study on operational condition of hypolimnetic aerators

1996 ◽  
Vol 34 (7-8) ◽  
pp. 211-218 ◽  
Author(s):  
Y. Nakamura ◽  
T. Inoue
Keyword(s):  
Theoretical Basis ◽  
Present Model ◽  
Theoretical Study ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Quantitative Prediction ◽  
Necessary Condition ◽  
Phosphate Release ◽  
Hypolimnetic Oxygen ◽  
Simple Mass

A theoretical basis for the operational condition of hypolimnetic aerators is described. The widely observed increase in hypolimnetic oxygen demand during aeration is ascribed to enhanced sediment oxygen demand due to induced circulation currents. The present model enables quantitative prediction of dissolved oxygen and phosphate concentrations during hypolimnetic aeration. Simple mass balance in the hypolimnoin shows a necessary condition to halt phosphate release. A time scale of changes in oxygen concentration is also discussed. These results will assist in designing an aerator and selecting an optimum operational condition.

scholarly journals RESPONSE OF SOD AND PHOSPHATE RELEASE RATE DUE TO STEP CHANGES IN DO CONCENTRATION AND FLOW VELOCITY

1999 ◽  
Vol 43 ◽  
pp. 1013-1018
Author(s):  
Tetsunori INOUE ◽  
Yoshiyuki NAKAMURA ◽  
Yoshihiko ADACHI
Keyword(s):  
Flow Velocity ◽  
Release Rate ◽  
Phosphate Release ◽  
Do Concentration

scholarly journals Pollution mapping in the urban segment of a tropical river: is water quality index (WQI) enough for a nutrient-polluted river?

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Kashifa Iqbal ◽  
Shamshad Ahmad ◽  
Venkatesh Dutta
Keyword(s):  
Water Quality ◽  
Biochemical Oxygen Demand ◽  
Water Quality Index ◽  
Quality Index ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Tropical Rivers ◽  
Polluted River ◽  
Gomti River

Abstract Most of the tropical rivers of the world are being affected by multiple sources of pollution. The intensity of pollution is much bigger in the urban stretches due to discharge of untreated or partially treated sewage. A rapid and cost-effective tool is required for identification of water quality problems and their spatial variation for determining the main pollution sources and to detect relationships between various parameters. For this study, Gomti River, a major tributary of River Ganges, India, was considered which has gained substantial attention because of increasing anthropogenic pollution loads that has badly affected its water quality and ecosystem functions. The urban segment is polluted with organic substances, nutrients and heavy metals. The study provides an overview of the quality of water in the Gomti River through water quality index (WQI) and multivariate statistical techniques to check if WQI is enough for a nutrient-polluted river in the urban stretch. The study suggests that periodic monitoring and the water quality index development are not enough as it does not incorporate all the aspect of a rivers water quality. The separate assessment of nitrogenous biochemical oxygen demand, carbonaceous biochemical oxygen demand, sediment oxygen demand and the nitrification inhibition aspects are required to be integrated when developing a WQI. Present study illustrates that water quality of Gomti River has gradually worsened from upstream and downstream to middle stretch. The middle stretch was found to be most polluted as the major drains are concentrated within this stretch. Principal component analysis/factor analysis (PCA/FA) helped in obtaining and recognizing the factors/sources accountable for river water quality differences in the study area. The findings are useful for the decisions regarding water quality management and this can also be applied for speedy and low-cost assessment of water quality of the polluted urban stretch of other tropical rivers for better environmental management and planning perspective.

Effect of flow velocity on phosphate release from sediment

1994 ◽  
Vol 30 (10) ◽  
pp. 263-272 ◽  
Author(s):  
Yoshiyuki Nakamura
Keyword(s):  
Flow Velocity ◽  
Release Rate ◽  
Bulk Water ◽  
Low Flow ◽  
Limiting Factor ◽  
Phosphate Release ◽  
Release Flux ◽  
Diffusive Boundary ◽  
Do Concentration ◽  
Flow Velocities

A mathematical model of phosphate release rate from sediment, fp, is presented which determines the fp as a function of flow velocity over the sediment and dissolved oxygen concentration. Oxygen consumption in the sediment is expressed as the sum of chemical consumption due to ferrous iron oxygenation and the bacterial consumption which is assumed to be a first order reaction of oxygen. At very low flow velocities, transport through the diffusive boundary layer is the limiting factor of SOD, and phosphate release rate is expressed as a linear decreasing function of the velocity. When flow velocities are increased, both SOD and phosphate release rate become independent of velocity, since the reactions in the sediment are the rate limiting factor. The model suggests that phosphate release flux is a linear decreasing function of DO in the bulk water, while SOD is an increasing function of DO concentration. The critical DO concentration at which the phosphate release ceases is expressed in terms of the flow velocity. The prediction of SOD and ϕp by the present model is favourably compared with experiments by former researchers.

The Effect of Temperature on the Water Quality of Lake

2013 ◽  
Vol 821-822 ◽  
pp. 1001-1004
Author(s):  
Hong Yi Li ◽  
Jin Xu ◽  
Rui Qing Xu
Keyword(s):  
Total Nitrogen ◽  
Oxygen Demand ◽  
Ammonium Nitrogen ◽  
Effect Of Temperature ◽  
Effective Management ◽  
Nitrite Concentration ◽  
Nitrite Nitrogen ◽  
Increasing Trend ◽  
Do Concentration

Aiming at the increasing trend of pollution in Tianyin Lake watershed, more and more studied were carried out in order to alleviate lake eutrophication. COD(Chemical Oxygen Demand), TN(total nitrogen), DO (Dissolved Oxygen), NH4+-N (ammonium nitrogen), NO2--N (nitrite nitrogen) and PO43--P (phosphate) were measured for almost one month. The results showed that With the water temperature increasing, the DO concentration decreased; ammonia, nitrate,total nitrogen, COD, and phosphate increased; it had no effect on the nitrite concentration. This information was helpful in providing the basis for theoretical basis of effective management of lakes.

Modelling of sediment oxygen demand and organic flux for a pulsed sediment organic load

2006 ◽  
Vol 54 (11-12) ◽  
pp. 85-92 ◽  
Author(s):  
Y.X. Wang ◽  
X.Y. Li ◽  
J.H.W. Lee
Keyword(s):  
Surface Waters ◽  
Laboratory Experiments ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Organic Load ◽  
Organic Input ◽  
Fish Food ◽  
Organic Sediment ◽  
Diagenetic Reactions

Biodegradation of organic matter in the sediment affects both the level of dissolved oxygen (DO) in the overlaying water and material flux into the water body. In the present study, a mathematical model was developed to describe the DO dynamics and related organic transformation in the sediment after a pulsed load of rich organic, sediment. The model includes DO diffusion at the sediment–water interface and inside the sediment, diagenetic reactions of particulate organic to soluble organic, substances, biodegradation of soluble organic, and related DO consumption. The model can simulate sediment oxygen demand (SOD) in a dynamic system after a sudden organic load on the sediment and the flux of both biodegradable and non-biodegradable organic can be predicted. In addition, laboratory experiments were conducted using SOD chambers to investigate the SOD dynamics and sediment material fluxes. The sediment of the batch SOD tests was loaded with fish food at various rates for the sudden organic input. Numerical simulations for SOD and organic fluxes compared well with the experimental measurements. The results demonstrate that the model can be used to predict the effect of sediment pollutants on the water quality of surface waters.

Letter to the Editor: The Continuing Challenge of Evaluating RSD Impairment and Disability

1998 ◽  
Vol 3 (5) ◽  
pp. 8-10
Author(s):  
Robert L. Knobler ◽  
Charles N. Brooks ◽  
Leon H. Ensalada ◽  
James B. Talmage ◽  
Christopher R. Brigham
Keyword(s):  
Disability Evaluation ◽  
Body Part ◽  
Loss Of Function ◽  
Regulatory Requirements ◽  
Major Cardiac Event ◽  
Clinical Scenarios ◽  
Impairment Score ◽  
Occupational Activities ◽  
The Difference

Abstract The author of the two-part article about evaluating reflex sympathetic dystrophy (RSD) responds to criticisms that a percentage impairment score may not adequately reflect the disability of an individual with RSD. The author highlights the importance of recognizing the difference between impairment and disability in the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides): impairment is the loss, loss of use, or derangement of any body part, system, or function; disability is a decrease in or the loss or absence of the capacity to meet personal, social, or occupational demands or to meet statutory or regulatory requirements because of an impairment. The disparity between impairment and disability can be encountered in diverse clinical scenarios. For example, a person's ability to resume occupational activities following a major cardiac event depends on medical, social, and psychological factors, but nonmedical factors appear to present the greatest impediment and many persons do not resume work despite significant improvements in functional capacity. A key requirement according to the AMA Guides is objective documentation, and the author agrees that when physicians consider the disability evaluation of people, more issues than those relating to the percentage loss of function should be considered. More study of the relationships among impairment, disability, and quality of life in patients with RSD are required.

DECOLOURIZATION AND COD REMOVAL OF WASEWATER FROM ETHANOL PRODUCTION PROCESS FROM MOLASSES BY COAGULANTION USING INORGANIC ALUM

2010 ◽  
Vol 13 (3) ◽  
pp. 92-102
Author(s):  
Trung Duc Le
Keyword(s):  
Ethanol Production ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Treatment Processes ◽  
Physico Chemical ◽  
Biological Methods ◽  
Treatment Step ◽  
Main Material

The industrial production of ethanol by fermentation using molasses as main material that generates large quantity of wastewater. This wastewater contains high levels of colour and chemical oxygen demand (COD), that may causes serious environmental pollution. Most available treatment processes in Vietnam rely on biological methods, which often fail to treat waste water up to discharge standard. As always, it was reported that quality of treated wastewater could not meet Vietnameses discharge standard. So, it is necessary to improve the treatment efficiency of whole technological process and therefore, supplemental physico-chemical treatment step before biodegradation stage should be the appropriate choice. This study was carried out to assess the effect of coagulation process on decolourization and COD removal in molasses-based ethanol production wastewater using inorganic coaglutant under laboratory conditions. The experimental results showed that the reductions of COD and colour with the utilization of Al2(SO4)3 at pH 9.5 were 83% and 70%, respectively. Mixture FeSO4 – Al2(SO4)3 at pH 8.5 reduced 82% of colour and 70% of COD. With the addition of Polyacrylamide (PAM), the reduction efficiencies of colour, COD and turbidity by FeSO4 – Al2(SO4)3 were 87%, 73.1% and 94.1% correspondingly. It was indicated that PAM significantly reduced the turbidity of wastewater, however it virtually did not increase the efficiencies of colour and COD reduction. Furthermore, the coagulation processes using PAM usually produces a mount of sludge which is hard to be deposited.

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