Two Pilot Plant Reactors Designed for the In Situ Bioremediation of Chlorobenzene-contaminated Ground Water: Hydrogeological and Chemical Characteristics and Bacterial Consortia

The SAFIRA in situ pilot plant in Bitterfeld, Saxonia-Anhalt, Germany, currently serves as the test site for eight different in situ approaches to remediate anoxic chlorobenzene (CB)-contaminated ground water. Two reactors, both filled with originallignite-containing aquifer material, are designed for themicrobiological in situ remediation of the ground water bythe indigenous microbial consortia. In this study, thehydrogeological, chemical and microbiological conditions of theinflowing ground water and reactor filling material are presented,in order to establish the scientific basis for the start of thebioremediation process itself. The reactors were put intooperation in June 1999. In the following, inflow CB concentrationsin the ground water varied between 22 and 33 mg L^-1; achemical steady state for CB in both reactors was reachedafter 210 till 260 days operation time. The sediments werecolonized by high numbers of aerobic, iron-reducing anddenitrifying bacteria, as determined after 244 and 285 days ofoperation time. Furthermore, aerobic CB-degrading bacteria weredetected in all reactor zones. Comparative sequence analysis of16S rDNA gene clone libraries suggest the dominance of Proteobacteria (Comamonadaceae, Alcaligenaceae, Gallionella group, Acidithiobacillus) and members of theclass of low G+C gram-positive bacteria in the reactorsediments. In the inflowing ground water, sequences withphylogenetic affiliation to sulfate-reducing bacteria andsequences not affiliated with the known phyla of Bacteria, were found.     

Sustainability assessment with time-series scores: a case study of Chinese provinces

Asian nations are currently facing a number of challenges, including environmental degradation and growing societal inequalities, in the course of their rapid economic growth and industrialization. Under such conditions, it is of critical importance to develop appropriate assessment tools with which to comprehensively measure the sustainability status of a region in order to guide its transformation into a sustainable society. This paper proposes a method of sustainability assessment consisting of the three components of environment, resource, and socio-economic with aggregated time-series scores. This method can demonstrate the relative sustainability scores of targeted regions for different time periods, thereby, enabling the comparison of relative sustainability status for different regions over these periods. We carried out a case study of Chinese provinces for the years 2000 and 2005 using the proposed method and confirmed its applicability as the indicative type of sustainability assessment at the regional level, while actually investigating the sustainability status and its chronological changes. The results indicated that aggregate sustainability index scores improved between 2000 and 2005 in most provinces, mainly due to significant improvement in the scores for the socio-economic component, whereas the scores for the environment component deteriorated in some provinces over the study period. Our method proves to be effective in analyzing the relative sustainability status among targeted regions for different time periods in the form of aggregate scores, paving the way for practical applications, such as policy analysis, in the pursuit of a sustainable society.     

Medical radioisotopes in the environment – following the pathway from patient to river sediment

Motivated by the detection of ¹³¹I in river sediment in routine long-term surveillance samples, a systematic short-term study of the wastewater treatment chain was planned and conducted. Inflow, effluent and primary sludge were collected on a daily basis during two weeks at a regional wastewater treatment plant. Samples were investigated by gamma spectroscopy. Four medically used isotopes could be identified (¹³¹I and ^99mTc regularly, ¹⁵³Sm and ¹²³I sporadically). The concentration levels coincide well with literature data for ¹³¹I, and with our own long-term data for ¹³¹I and ^99mTc for the same plant. Cosmogenic ⁷Be activity in primary sludge correlated well with rainfall intensity. Surface sediment was sampled at low tide at both shores of the river, up- and downstream of the plant. ¹³¹I was identified in all samples, with a sharp maximum (about 100 Bq kg⁻¹ d.m.) at the discharge point of the plant and lower levels elsewhere, decreasing monotonically in downstream direction. ⁷Be and ¹³⁷Cs showed the same behaviour, but no peak at the discharge point. Predictions from simple equilibrium models for the transport and sedimentation of ¹³¹I show good agreement with the experimental data and suggest that the wastewater treatment plant is the main source for this isotope.