Monitoring dissolved organic carbon in surface and drinking waters

The presence of natural organic matter (NOM) strongly impacts drinking water treatment, water quality, and water behavior during distribution. Dissolved organic carbon (DOC) concentrations were determined daily over a 22 month period in river water before and after conventional drinking water treatment using an on-line total organic carbon (TOC) analyzer. Quantitative and qualitative variations in organic matter were related to precipitation and runoff, seasons and operating conditions. Following a rainfall event, DOC levels could increase by 3.5 fold over baseflow concentrations, while color, UV absorbance values and turbidity increased by a factor of 8, 12 and 300, respectively. Treated water DOC levels were closely related to the source water quality, with an average organic matter removal of 42% after treatment.     

IMPLEMENTATION OF BIORETENTION SYSTEMS: A WISCONSIN CASE STUDY1

ABSTRACT: The implementation of various bioretention systems was analyzed, including rain gardens, vegetated swales, trenches, and infiltration basins in the St. Francis subdivision, Cross Plains, Wisconsin. Through the examination of archival data and interviews with key participants, it was found that although regulatory and political pressures encouraged the inclusion of bioretention, current standards for storm water management prevailed. The developers had to meet both existing requirements and anticipated rules requiring infiltration. As a result, bioretention systems simply supplemented, rather than replaced, traditional storm water practices. The confusion surrounding dual standards contributed to substantial delays in the negotiations among relevant stakeholders in the watershed. It is concluded that the St. Francis subdivision serves as both a cautionary tale and a bioretention success story. As a caution, this situation demonstrates the need for careful review and refinement of existing storm water ordinances to incorporate water quality improvement technologies, such as bioretention. The demonstrated success of the St. Francis development, however, is that it became a positive prototype for best management storm water practices elsewhere in the region. In addition, the water quality monitoring data from the site has contributed to development of a new county ordinance, the first in Wisconsin to address both quantity and quality of storm water runoff.     

Assessment of different carbon and salinity level on growth kinetics,lipid, and starch composition of Chlorella vulgaris SAG 211-12

ABSTRACT

The quality of microalgal biofuel depends on the fatty acid (FA) distribution. A high ratio of saturated fatty acids (SFAs) favors better biofuel characteristics. Palmitic acid (C16:0) and stearic acid (C18:0) are essential FAs for required biodiesel quality. In this study, combined effects of growth medium concentrations of NaCl, glucose and glycerol on cell composition and FA profile of the Chlorella vulgaris SAG 211–12 were investigated. A central composite design (CCD) based design of experiments (DoE) was used for experimental setup. According to experimental results, the maximum mass fraction for palmitic acid (C16:0), 40.67% of total fatty acids, was obtained in the medium supplemented with 0.9% (w/v) NaCl, 0.3% (w/v) glucose, and 0.3% (w/v) glycerol, whereas stearic acid (C18:0) percentage reached the highest value of 22.16% of total fatty acids in the presence of 2.5% NaCl, 0.6% glucose, and 0.6% glycerol. According to the same set of designed experiments, best starch content was found as 22.08% of dry cell weight in a medium containing 2.0% NaCl, 0.3% glucose, and 0.3% glycerol. C16:0 mass fraction as a function of three medium ingredient concentrations was modeled using a Kriging model. Optimum concentrations of NaCl, glucose and glycerol to reach maximum C16:0 fraction were predicted as 0.5, 1, and 1%, respectively.     

Book reviews

Factor Four: Doubling Wealth, Halving Resource Use. Ernst von Weizacker, Amory Lovins & L. Hunter Lovins, 1997, London, Earthscan, ISBN 1 85383 407 6, £15.99 (hbk)

Local and Global: Management of Cities in the Information Age,. Jordi Borja & Manuel Castells, 1997, London, Earthscan, 277pp. ISBN 1 85383 441 6, £19.95 (pbk)

Wasted: counting the costs of global consumption. Michael Redclift, 1996, Earthscan, London, 173pp. ISBN 1 85383 360 6, £32.50(hbk), 1 85383 355 X, £12.95(pbk)

Eco-feminist Natures: race, gender, feminist theory and political action. Noel Sturgeon, 1997, New York, Routledge, ISBN 0 415 912504, £12.99 (pbk)

Global Warming and Global Politics. Matthew Paterson, 1996, London and New York, Routledge, ISBN 0 415 13871 X, US$85.00, UK£50.00, (hbk) ISBN 0 415 13872 8, US$20.99, UK£12.88, (pbk)

Managing for Local Sustainability: policy, problem-solving, practice and place. Valerie M. Brown (Ed.), 1997, Commonwealth of Australia, 314 pp. ISBN 0642 26464 3, Copies of the report can be obtained from: National Office of Local Government Commonwealth Department of the Environment, Sports and Territories, GPO Box 9834, Canberra ACT 2601. Tel: (06) 289 2222; fax (06) 289 2436.

Local Agenda 21, Local Authorities and Tourism: a United Kingdom perspective. David Leslie & Fiona Muir, 1996, Glasgow, Caledonian University, ISBN 0 948255 52 8, £9.00

Straws in the Wind: medieval urban environmental law — the case of Northern Italy. Ronald E. Zupko & Robert A. Laures, 1996, Boulder, CO, Westview Press, 152 pp. ISBN 0 8133 2972 8, £10.00 (pbk)     

A plasma display window?-The shifting baseline problem in a technologically mediated natural world

Humans will continue to adapt to an increasingly technological world. But are there costs to such adaptations in terms of human well being? Toward broaching this question, we investigated physiological effects of experiencing a HDTV quality real-time view of nature through a plasma display “window.” In an office setting, 90 participants (30 per group) were exposed either to (a) a glass window that afforded a view of a nature scene, (b) a plasma window that afforded a real-time HDTV view of essentially the same scene, or (c) a blank wall. Results showed that in terms of heart rate recovery from low-level stress the glass window was more restorative than a blank wall; in turn, a plasma window was no more restorative than a blank wall. Moreover, when participants spent more time looking at the glass window, their heart rate tended to decrease more rapidly; that was not the case with the plasma window. Discussion focuses on how the purported benefits of viewing nature may be attenuated by a digital medium.