Mineralisation of Monuron photoinduced by Fe(III) in aqueous solution

The degradation of Monuron (3-(4-chlorophenyl)-1,1-dimethylurea) photoinduced by Fe(III) in aqueous solution has been investigated. The rate of degradation depends on the concentration of Fe(OH)2+, the most photoreactive species in terms of *OH radical formation. These *OH radicals are able to degrade Monuron until total mineralisation. The primordial role of the speciation of Fe(III)-hydroxy complex in aqueous solution, for the efficiency of the elimination of pollutant, was shown and explained in detail. The formation of Fe(II) in the irradiated solution was monitored and correlated with the total organic carbon evolution. Degradation photoproducts were identified and a mechanism of degradation is proposed.     

Optimization of anaerobic digestion of municipal solid waste in combined process and sequential staging.

The optimization of anaerobic digestion aims to maximize organic waste stabilization after a short digestion period. This paper presents the optimization performance of the combined anaerobic digestion and sequential staging concept in a thermophilic, solid-state batch system as a treatment technology prior to landfill. The former involves enhanced pre-stage flushing with the addition of microaeration and inoculum in the methane phase. The latter involves leachate cross-recirculation between the mature and fresh waste reactors without conducting a pre-stage operation. The optimized process for combined anaerobic digestion showed that reducing the pre-stage operation with the maximum removal of organics from the waste bed is beneficial. Moreover, the sequential staging concept offers an improved process over the combined anaerobic digestion wherein the specific methane yield of 11.9 and 7.2 L CH4 kg(-1) volatile solids (VS) per day was achieved, respectively. After 28 days of operation, the sequential staging process showed an improved waste stabilization with 86 and 79% mass and volume reduction, respectively. A higher methane yield of 334 L CH4 kg(-1) VS with 86% VS reduction, which is equivalent to 84% process efficiency was obtained.     

Policy And Practice Options for Managing Protected Areas: Lessons from International Experience

There is now a wealth of international experience and lessons about options for managing environmentallysensitive zones. This paper1 provides a brief guide to two sets of options, regulatory instruments and incentive measures, that are commonly used to manage special areas. Managementapproachesthat combine both sets of tools are then reviewed, including integrated coastal zone management, municipal-level programmes and efforts to promote sustainable local development such as eco-tourism. The paper concludes that, regardless of which approach is applied to a protected area, the key threats to an area's sustainability must be identified and addressed. Examples and case studies of both good and poor practice are included to illustrate the use of different options. In order to sustain our global environment and improve the quality of living in our human settlements, we commit ourselves to sustainable patterns of production, consumption, transportation and settlement development, pollution prevention, respect for the carrying capacity of eco-systems, and the preservation of opportunities for future generations. (Istanbul Declaration on Human Settlements, June 1996)     

Can city QOL indicators be objective and relevant? Towards a participatory tool for sustaining urban development

The paper concludes its first section by answering the title question: no, QOL indicators cannot be purely objective but yes, they can be relevant while being subjective. The second section develops a framework for making measures of urban QOL more relevant. The objective is that such indicators can be a useful tool for sustaining urban development into the next millennium. The framework consists of three elements: (a) a process—QOL indicators should be locally developed through an approach that combines expertise with stakeholder consultation; (b) an output—developing, collecting and evaluating QOL measurements should be linked to implementation of policies, programmes and/or projects; and (c) a method—a series of tested guidelines should be applied to ensure that QOL indicators are realistic, both logistically (they can be collected) and analytically (they are appropriate measures). Real-world examples are used to illustrate points made in the paper.     

Geochemical and Pb isotopic evidence for sources and dispersal of metal contamination in stream sediments from the mining and smelting district of Príbram, Czech Republic

Stream sediments from the mining and smelting district of Príbram, Czech Republic, were studied to determine the degree, sources and dispersal of metal contamination using a combination of bulk metal and mineralogical determinations, sequential extractions and Pb isotopic analyses. The highest metal concentrations were found 3-4 km downstream from the main polymetallic mining site (9800 mg Pb kg(-1), 26 039 mg Zn kg(-1), 316.4 mg Cd kg(-1), 256.9 mg Cu kg(-1)). The calculated enrichment factors (EFs) confirmed the extreme degree of contamination by Pb, Zn and Cd (EF>40). Lead, Zn and Cd are bound mainly to Fe oxides and hydroxides. In the most contaminated samples Pb is also present as Pb carbonates and litharge (PbO). Lead isotopic analysis indicates that the predominant source of stream sediment contamination is historic Pb-Ag mining and primary Pb smelting (206Pb/207Pb=1.16), while the role of secondary smelting (car battery processing) is negligible.