Biodegradation of linear alcohol ethoxylates in natural waters

Larson, Robert J.; Games, Larry M.

doi:10.1021/es00094a011

Cited by 46 publications

(19 citation statements)

References 8 publications

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“…Experiments carried out in different parts of the world show that in the arid or semi-arid areas where human, animal and bird life are extremely scarce, as in the arid zone of Australia, bacterial action on the film is very rare. But in thickly populated areas in the tropics and subtropics the bacterial destruction plays a more prominent part [58]. Any foreign substance which is absorbed by the film restricts its movement by rendering it inelastic.…”

Section: Life Of Monomolecular Film Over Watermentioning

confidence: 99%

Evaporation Retardation by Monomolecular Layers: An Experimental Study at the Aji Reservoir (India)

Panjabi¹,

Rudra²,

Goel³

2016

OJCE

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It is an established fact that huge quantities of water are lost from lakes, reservoirs and soils by evaporation. This assumes greater significance in arid and semi-arid regions around the globe when a general scarcity of water is compounded by high evaporation loss from the open water surfaces of lakes and reservoirs. The use of surface covering by a monomolecular film to reduce evaporation loss from large open water surfaces offers the greatest promise among all currently available techniques. This is the only system that retains the water surface in a state that does not interfere with other uses of the body of water such as boating, navigation recreation, fish, and wildlife propagation. Various experiments and field trials worldwide have proven conclusively that the fatty alcohols and their emulsions effectively retard water evaporation and result in saving to the tune of about 20% to 50%. An experiment was carried out at the Aji Reservoir (India) using a mixture of Cetyl and Stearyl alcohol that confirmed 19.26% saving in evaporation loss. During this six-month trial, about 0.18 mcum of water was saved which otherwise might have evaporated.

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Section: Life Of Monomolecular Film Over Watermentioning

confidence: 99%

Evaporation Retardation by Monomolecular Layers: An Experimental Study at the Aji Reservoir (India)

Panjabi¹,

Rudra²,

Goel³

2016

OJCE

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“…Surfactant-degrading microorganisms are present in many ecosystems (Larson & Games 1981;Gledhill et al 1991;Sigoillot & Nguyen 1992). They usually occur in mixed populations of hydrophobic and hydrophilic moiety-degrading species.…”

Section: Natural Ecosystemsmentioning

confidence: 99%

Complete degradation of xenobiotic surfactants by consortia of aerobic microorganisms

Ginkel

1996

Biodegradation

163

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Linear alkylbenzene sulphonates are primarily attacked via a hydroxylation of the alkyl chain from the methyl group followed by beta-oxidation. The alkyl chain is metabolized by pure cultures to give sulphophenyl carboxylates which accumulate in the medium. In mixed culture, other microorganisms are capable of degrading sulphophenyl carboxylates. Formation of ethylene glycol monosulphates as major products of alkyl ethoxy sulphates demonstrates that the ether bonds are cleaved. The bacteria involved in growing on the alkyl chain are unable to utilize the hydrophilic moiety. This hydrophilic moiety, in turn, is degraded by other microorganisms. The degradation of alkylphenol ethoxylates and highly branched alcohol ethoxylates proceeds by shortening the polyoxyethylene chain leaving the hydrophobic part of the molecule. The biodegradation of linear alcohol ethoxylates and ethoxylated fatty amines is initiated by a central cleavage or omega-oxidation. Subsequent oxidation of the alkyl chains results in the production of polyethylene glycols and secondary ethoxylated amines. Both polar moieties are metabolized by other microorganisms. Degradation of alkyltrimethylammonium salts and alkylamines is initiated by a cleavage of the Calkyl-N bond. The central fission leads to the formation of alkanals which are readily converted by beta-oxidation. The alkyl chain-utilizing bacteria are not able to degrade the methylamines. The methylamines, in turn, are subject to biodegradation by methylotrophs. The limited metabolic capacities of pure cultures of microorganisms utilizing surfactants point to the requirement of consortia to degrade surfactants completely. Complete degradation of surfactants is accomplished by mixed cultures of microorganisms constructed on the basis of synergistic and commensalistic relationships. However, degradation of a surfactant by one member of a commensalistic consortium may lead to the production of toxic or non-toxic metabolites. Waste water treatment without the build up of such metabolites can be achieved in plants operated with sludge retention times that are suitable for maintaining all microorganisms of the consortium. In contrast, in natural ecosystems the introduction of a surfactant may result in a transient formation of a metabolite.

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“…Larson studied the kinetics and affect of temperature on the biodegradation of C 16 E 3 and C 12 E 9 in river water [140] and groundwater [141] in the U.S.A. These pure chain compounds were labelIed either in the alkyl carbon or uniformly in the ethoxylate chain.…”

Section: )mentioning

confidence: 99%