Biodegradation of monoaromatic hydrocarbons in aquifer columns amended with hydrogen peroxide and nitrate

The ability of indigenous microorganisms to degrade benzene, toluene, ethylbenzene and xylenes (BTEX) in laboratory scale flow-through aquifer columns was tested separately with hydrogen peroxide (110 mg/l) and nitrate (330 mg/l as NO₃⁻) amendments to air-saturated influent nutrient solution. The continuous removal of individual components from all columns relative to the sterile controls provided evidence for biodegradation. In the presence of hydrogen peroxide, the indigeneous microorganisms degraded benzene and toluene (> 95%), meta- plus para-xylene (80%) and ortho-xylene (70%). Nitrate addition resulted in 90% removal of toluene and 25% removal of ortho-xylene. However, benzene, ethylbenzene, meta- and para-xylene concentrations were not significantly reduced after 42 days of operation. Following this experiment, low dissolved oxygen (< 1 mg/l) conditions were initiated with the nitrate-amended column influent in order to mimic contaminated groundwater conditions distal from a nutrient injection well. Toluene continued to be effectively degraded (> 90%), and more than 25% of the benzene, 40% of the ethylbenzene, 50% of the meta- plus para-xylenes and 60% of the ortho-xylene were removed after several months of operation.     

A review of contractor selection practice in the U.K. construction industry

Background, prime influences upon present day methods and current trends in United Kingdom tendering practices are reviewed. Significant weaknesses are identified, confirming the need for some revision of existing contractor selection methods. The findings compliment recommendations of the recent government/industry review of the construction sector headed by Sir Michael Latham. Specifically, that tendering procedure should embrace investigation of contractors' potential to deliver a service of acceptable standard, on time, within budget. Present selection methods often fail in this objective, being inclined to discriminate predominantly on cost.     

Sulfat-dominierter BTEX-Abbau im Grundwasser eines ehemaligen Gaswerksstandortes

In the area of a former gas-works in Düsseldorf (Germany) a soil and groundwater contamination with up to 100 mg/l BTEX (benzene, toluene, ethylbenzene and xylenes) was investigated. Benzene is the dominant aromatic hydrocarbon in the groundwater. The investigations show a natural biodegradation of BTEX by oxygen, manganese oxides, nitrate, ferric hydroxide and sulfate in the sand and gravel aquifer. Sulfate reduction is the most important degradation process in the contamined groundwater. As a product of sulfate reducion, sufids were formed in the sediments of the aquifer. A balance of oxidants is presented as a tool to quantify BTEX degradation and to differ this from sorption and dilution processes. In the contaminated area the degradation of aromatic hydrocarbons leads to the release of carbon dioxide. The highest free CO ₂ -concentration was found in the region of the groundwater table. Outgassing of CO ₂ is important and was verified by deep-specific soil-gas sampling. The knowledge of these processes in the subsoil is a requirement for making predictions for in-situ remediation effects.     

Occurrence and behaviour of linear alkylbenzenesulphonates, nonylphenol, nonylphenol mono- and nonylphenol diethoxylates in sewage and sewage sludge treatment

The fluxes of linear alkylbenzenesulphonates (LAS), nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO) through sewage and sludge treatment of 29 Swiss sewage treatment plants were investigated. Reversed-phase high-performance liquid chromatography (HPLC) was used to determine LAS. Normal-phase HPLC was employed to measure NP, NP1EO and NP2EO which are metabolites of the nonionic surfactants of the nonylphenol polyethoxylate type (NPnEO). Quantitative determinations were performed of raw sewage, primary and secondary effluents and of sewage sludge. Under normal conditions of sewage and sludge treatment, LAS were efficiently removed from the raw wastewater (> 99% w/w) and were partly transferred to the sewage sludge (15–20% w/w). About 50% (molar base) of NPnEO in the sewage were transformed to NP and accumulated in the digested sludge. Large variations existed among different sewage treatment plants. It was estimated that 1.0 g m⁻² y⁻¹ of LAS and 0.3 g m⁻² y⁻¹ of NP are applied with sewage sludge to Swiss soils.     

Review

THE EXPERIENCE OF NATURE: A PSYCHOLOGICAL PERSPECTIVE by Rachel Kaplan & Stephen Kaplan, Cambridge University Press, 1989, 337pp, £10.95 (p/b), 0-521-34939-7.

THE ECOLOGY OF URBAN HABITATS by 0. L. Gilbert, Chapman & Hall, London, 1989, 369pp, 0-412-28270-4, £35.00.

DIRECTORY FOR THE ENVIRONMENT: ORGANISATIONS IN BRITAIN AND IRELAND 1986-7, Michael J. C. Barker, ed., London: Routledge & Kegan Paul, 1986. Second edition, pp. xviii + 278, £18.99, PB, ISBN 0-7102-0961-4.

THE URBAN ENVIRONMENT: A SOURCEBOOK FOR THE 1990s, Gerald Dawe, ed., Birmingham: Centre for Urban Ecology, 1990, pp. 636, £55.00, PB, ISBN 0-907272-07-X.

PLANTS IN THE LANDSCAPE (2nd Edn.), by Philip L. Carpenter and Theodore D. Walker, W. H. Freeman, New York and Oxford, 1990, 401 pp., ISBN 0-7167-1808-1, £29.95 HB.

SPORTS GEOGRAPHY by John Bale, E. & F. N. Spon, 1989, 0-419-14390-4, £16.95 PB.

THE POLITICS OF PARK DESIGN: A HISTORY OF URBAN PARKS IN AMERICA by Galen Cranz, ISBN 0 262 53084 8, 347pp, London: M.I.T. Press, 1989, £11.25, P.B.     

Review

Richard Mabey, Home Country London: Century 1990 £14.95

A Tour of the Lakes in Cumberland. John Ruskin's Diary for 1830. James S. Dearden, (Ed.), with an Introduction by Van Akin Burd. Scolar Press, Aldershot, 1990.

The Landscape Vision of Paul Nash, Roger Cardinal. Reaktion Books, London, 1989. £9,95 paperback ISBN 0948462 02 7

M G R Cannell & M D Hooper, The Greenhouse Effect and Terrestrial Ecosystems of the UK London, HMSO, 1990. 56pp. £4.95

Amenity In Action, The Civic Trust Handbook of Community Initiatives compiled & edited by Deirdre Genet, Societies Development Officer, The Civic Trust (1989), (supported by the Shell Better Britain Campaign)

Sue Minter The Greatest Glass House: The rainforests recreated HMSO, 1990. £25.00     

Reviews

A VISUAL APPROACH TO PARK DESIGN by A. J. Rutledge, John Wiley, 1985. 180pp.

FIFTY YEARS OF LANDSCAPE DESIGN: 1934-84 Edited by Sheila Harvey and Stephen Rettig, Landscape Press, 1985.

DES PAYSAGES, POUR QUI? POURQUOI? COMMENT? by Georges Neuray, Les Presses Agronomiques de Gembloux, Belgium, 1982, 589 pp. 1640 Belgian Francs.

THE PAST IS A FOREIGN COUNTRY by Professor David Lowenthal, Cambridge University Press, 1985, 490 pp, £27.50 (H/B), £9.95 (P/B).

INTERPRETING THE LANDSCAPE: LANDSCAPE ARCHAEOLOGY IN LOCAL STUDIES by Michael Aston. B. T. Batsford, London 1985. Price £9.95 (P/B).

AGRICULTURAL LANDSCAPES: A SECOND LOOK, by R. Westmacott and T. Worthington, Countryside Commission (CCP 168, 1984) £7.00

AGRICULTURAL LANDSCAPES: AN APPROACH TO THE IMPROVEMENT, by P. Hamilton and J. Woolcock, Countryside Commission (CCP 169, 1984) £8.00

AGRICULTURAL LANDSCAPES: DEMONSTRATION FARMS, by R. Cobham et al, Countryside Commission (CCP 170, 1984) £13.00

REVIEWS OF UNITED KINGDOM STATISTICAL SOURCES, VOLUME XVII, Weather by B. W. Atkinson and Water by E. C. Penning-Rowsell and D. J. Porter. Published for the Royal Statistical Society and Economic and Social Research Council by Pergamon Press, 1985, 266 pp.

THE COUNTRYSIDE HANDBOOK by Alan Rogers, John Blunden and Nigel Curry, Open University/Croom Helm, 1985, 98 pp, £5.95.

THE CHANGING COUNTRYSIDE — edited by John Blunden and Nigel Curry. Open University/Croom Helm, 1985, 270 pp, £11.95.     

Géologie de l'ingénieur appliquée aux études de,mise en valeur d'un site historique et de son environnement,Crète,Grèce

The paper deals with the engineering Geological studies applied to the protection and development of a historical site, the Arkadi Monastery, in Crete, (XIIth, century). The geomorphological mapping allows to point out the areas which are concerned by the problems of environmental protection—natural sites, plateaus, karstic phenomenons, gorges. Such a mapping may also be used for the protection against floods and for the design of the plateaus drainage. The geological mapping deals with, the whole area, and takes into account the lithology, the weathering, the problems concerning the earthworks and the foundations. Slope stability is presented on a separate map. The hydrological study deals with the different conditions of the area—alluvial aquifers, scattered aquifers, karstic aquifers—and proposes solutions for the water supply and for the drainage in the area—alluvial aquifers, scattered aquifers, karstic aquifers—and proposes solutions for the water supply and for the drainage in the area. A special attention is paid to the weathering of the building stones which were used for the construction of the monastery —limestones—and to the survey of similar deposits with a view to its restoration. Finally, the study deals with the seismic risks—neotectonic phenomenons, and statistical interpretation of seismic data.     

The effect of wastewater phosphorus removal on shagawa lake, Minnesota: phosphorus supplies, lake phosphorus and chlorophyll a

In early 1973, the phosphorus supply to Shagawa Lake, Minnesota, was reduced by about 80% when a tertiary wastewater treatment plant began operating. Significant reductions in total and soluble reactive phosphorus concentrations have occurred in the lake since that time. By 1976 the average (volume weighted over the entire lake) total and soluble reactive phosphorus concentrations had declined from about 51 and 21 μg l⁻¹ to about 30 and 4.5 μg l⁻¹, respectively, corresponding to 40 and 80% reductions. During 1975 and 1976, chlorophyll a (averaged over the top 5 m) had decreased to less than 50% of the pretreatment level during May-June but during July-August little change had occurred.

A phosphorus residence time model projected equilibrium total phosphorus concentrations of about 12 μg l⁻¹ within 1.5 years. The fact that this level was not reached is attributed to a feedback of phosphorus from the sediments, primarily during summer. This phenomenon has been incorporated into a modified total phosphorus mass balance model which projects the phosphorus pattern through 1976 quite accurately. The close fit of the modified mass balance model implies that the phosphorus supply from the sediments has not diminished since treatment since treatment began, and that further recovery of the lake will depend upon how long this feedback of phosphorus from the sediments continues.