Surveillance of Invasive Bacterial Pathogens and Human Enteric Viruses in Wastewater Final Effluents and Receiving Water Bodies – a Case Study from Durban,South Africa

The physico‐chemical characteristics and microbial composition of the final effluents of two municipal wastewater treatment plants in South Africa were assessed between July and September 2009. The impact of the treated final effluents on the receiving water bodies was also evaluated. The temperature across all sampling points ranged between 14 and 22°C, while pH varied from 6.9 to 7.6. High levels of turbidity, chemical oxygen demand (COD), ammonia, nitrate, nitrite and orthophosphate (PO₄) were observed in many cases. Turbidity of the samples was in the range of 2.2–288.6 NTU. The concentrations (mg/L) of other physico‐chemical parameters are as follows: COD (9.33–289); ammonia (0.000340–45.4); nitrate (0.062–539); nitrite (0.021–22.6); PO₄ (5.3–33.2). The microbial quality of the effluents discharged from the plants did not comply with the limits set by the South African guidelines with respect to pathogens such as Salmonella, Shigella, Escherichia coli, total coliform, faecal coliform, enterococci, faecal streptococci, and viral particles for effluents intended for discharge into receiving watersheds. This study revealed an undesirable impact on the physico‐chemical and microbial qualities of the receiving water bodies as a result of the discharge of inadequately treated effluents from the wastewater treatment facilities. This poses a health risk to several rural communities which rely on the receiving water bodies primarily as their sources of domestic water and recreational purposes. There is therefore a need for the intervention of appropriate regulatory agencies in South Africa to ensure compliance of treatment facilities with wastewater effluent quality standards.     

Assessing vulnerability to drought based on exposure, sensitivity and adaptive capacity: A case study in middle Inner Mongolia of China

In this paper,we proposed a framework for evaluating the performance of ecosystem strategies prepared for enhancing vulnerability reduction in the face of hazards due to climate change.The framework highlights the positive effects of human activities in the coupled human and natural system(CHANS) by introducing adaptive capacity as an evaluation criterion.A built-in regional vulnerability to a certain hazard was generated based upon interaction of three dimensions of vulnerability:exposure,sensitivity and adaptive capacity.We illustrated the application of this framework in the temperate farming-grazing transitional zone in the middle Inner Mongolia of the northern China,where drought hazard is the key threat to the CHANS.Specific indices were produced to translate such climate variance and social-economic differences into specific indicators.The results showed that the most exposed regions are the inner land areas,while counties located in the eastern part are potentially the most adaptive ones.Ordos City and Bayannur City are most frequently influenced by multiple climate variances,showing highest sensitivity.Analysis also indicated that differences in the ability to adapt to changes are the main causes of spatial differences.After depiction of the spatial differentiations and analysis of the reasons,climate zones were divided to depict the differences in facing to the drought threats.The climate zones were shown to be similar to vulnerability zones based on the quantitative structure of indexes drafted by a triangular map.Further analysis of the composition of the vulnerability index showed that the evaluation criteria were effective in validating the spatial differentiation but potentially ineffective because of their limited time scope.This research will be a demonstration of how to combine the three dimensions by quantitative methods and will thus provide a guide for government to vulnerability reduction management.     

Thinking Outside the Boxcar: Effective and Sustainable Combined Remedies Using Single Application of Multifunctional Amendments

The combined remedy approach to groundwater remediation optimizes contaminated site cleanup as measured by technical efficacy and sustainability. Regardless of the potential for improving site cleanups, there are several obstacles limiting the implementation of combined remedies. The obstacles primarily stem from an inability of liability owners to easily determine if economic costs are synergistic or additive and from regulatory hesitancy to codify needed timing and technology sequencing flexibility within design documents. These obstacles can often be circumvented by employing multicomponent and multifunctional remedial amendment formulations delivered with a single application. Case studies are presented that demonstrate efficacy of this combined remedies approach. The sustainability of the approach is also assessed by evaluation of economic viability, social productivity, and environmental protection. The case studies include combined abiotic and biotic degradation of chlorinated ethene and ethane compounds, combined reductive, and microaerophilic treatment of chlorinated benzenes, and combined chemical oxidation and biodegradation of petroleum compounds. Case studies are supported with conventional concentration trends and advanced diagnostics including compound specific isotope analysis (CSIA) and genetic‐based molecular biological tools (MBTs).     

Assessing agricultural and hydrological drought vulnerability in a savanna ecological zone of Sub-Saharan Africa

Natural Hazards - Despite measures to mitigate drought, study on the extent of agricultural and hydrological drought vulnerability is still neglected in the savanna ecological zone of Nigeria. This...     

Geostatistical techniques for incorporating spatial correlation into land use change models

Land use modeling requires large amounts of data that are typically spatially correlated. This study applies two geostatistical techniques to account for spatial correlation in residential land use change modeling. In the first approach, we combined generalized linear model (GLM) with indicator kriging to estimate the posterior probability of residential development. In the second approach, generalized linear mixed model (GLMM) was used to simultaneously model spatial correlation and regression fixed effects. Spatial agreement between actual and modeled land use change was higher for the GLM incorporating indicator kriging. The GLMM produced more reliable estimates and could be more useful in analyzing the effects of driving factors of land use change for land use planning.