Rivers eutrophication

Biodegradation estimated t,A = 190 h in river, eutrophic pond, eutrophic lake and t,A > 106 h in oligotrophic lake by the one compartment model (Smith et al. 1978). 

Oxidation laboratory investigated k < 7.5 M1 s 1 for the reaction with R02 radical and estimated t,/2 > 10s h in river, eutrophic pond, eutrophic lake and oligotrophic lake by the one compartment model (Smith et al. 1978). k = 1.5 x lCH5 s 1 with t,/2 = 128 h under natural sunlight conditions, k < 7.5 M 1 s 1 with t,/2 > 3.5 yr for free-radical oxidation in air-saturated water (NRCC 1983)... 

The purpose of this work is to develop mathematical model for small rivers eutrophication taking into account the regional conditions. 

Physical controls are generally only applicable in lakes. The infinence of river morphology on eutrophication is not sufficiently well understood to be used effectively. The exception to this would be the short-term use of high flow to reduce the retention time to levels which limit growth rates of nuisance species such as cyanobacteria. 

Water pollution Deposited material or percolate escapes either by surface run-off or by underground movement, threatening streams, rivers, aquifers or the sea Direct poisoning or eutrophication... 

Mechanistic Approaches. Adequate and appropriate river-quality assessment must provide predictive information on the possible consequences of water and land development. This requires an understanding of the relevant cause and effect relationships and suitable data to develop predictive models for basin management. This understanding may be achieved through qualitative, semi-quantitative or quantitative approaches. When quantitative or semi-quantitative methods are not available the qualitative approach must be applied. Qualitative assessments involve knowledge of how basin activities may affect river quality. This requires the use of various descriptive methods. An example of this kind of assessment is laboratory evaluation of the extent to which increases in plant nutrients, temperature or flow may lead to accelerated eutrophication with consequent reduction of water quality. 

Barranguet C, Plans M, Van der Grinten E, Sinke JJ, Admiraal W (2002) Development of photosynthetic biofilms affected by dissolved and sorbed copper in a eutrophic river. Environ Toxicol Chem 21 1955... 

Ammonia and acetic acid in waste water give rise serious pollution problems which bring about eutrophication of rivers, lakes, etc [1, 2]. These have been treated by the conventional method of biological techniques, adsorption, and thermal incineration. A band of researchers have suggested that the ammonia molecules could be transferred to N2 using a photocatalytic redox mechanism as shown follows 4NH3 + 3O2 2N2 + 6H2O. However, it has been... 

An unusual example of a process that produces a lot of waste is the intensive rearing of pigs. They need additional phosphorus in their feed for healthy growth, and this is usually added as inorganic phosphorus in the form of monocalcium phosphate (calcium dihydroxy-oxido-oxo-phosphorane). Unabsorbed phosphorus passes through into the manure, and if spread onto fields as a fertiliser can lead to excess phosphorus run-off into rivers and lakes leading to eutrophication. 

Oxidation rate constant k, for gas-phase second order rate constants, k0H for reaction with OH radical, kNOa with N03 radical and k0j with 03 or as indicated, data at other temperatures see reference t,/2 > 340 h in river water, eutrophic pond or lake and oligotrophic lake, half-lives predicted by one compartment model (Smith et al. 1978)... 

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