No abstract

No abstract

Wastewater from defect sewers can affect groundwater quality. An assessment of this environmental impact for a city of 50 000 inhabitants (Rastatt, SW Germany) was done using marker species distributions, condition monitoring of the sewer network, lab‐scale analogy experiments, and specifically instrumented in‐situ test sites near defect sewers. The studies revealed elevated concentrations of iodated X‐ray contrast media (up to 360 ng/L amidotrizoic acid) and boron concentrations in the urban groundwater which are directly related to leaky sewers. Other common pharmaceuticals could not be detected in the groundwater. Observation wells were installed based on the information from a sewer defect database. These wells focusing on specific sewer leakages show significant changes in groundwater quality parameters.

Wastewater pipeline leakage is an emerging concern in Europe, especially with regards to the potential effect of leaking effluent on groundwater contamination and the effects infiltration has on the management of sewer reticulation systems. This paper describes efforts by Australia, in association with several European partners, towards the development of decision support tools to prioritize proactive rehabilitation of wastewater pipe networks to account for leakage. In the fundamental models for the decision support system, leakage is viewed as a function of pipeline system deterioration. The models rely on soil type identification across the service area to determine the aggressiveness of the pipe environment and for division of the area into zones based on pipe properties and operational conditions. By understanding the interaction between pipe materials, operating conditions, and the pipe environment in the mechanisms leading to pipe deterioration, the models allow the prediction of leakage rates in different zones across a network. The decision support system utilizes these models to predict the condition of pipes in individual zones, and to optimize the utilization of rehabilitation resources by targeting the areas with the highest leakage rates.

No abstract

Systems view thinking and holistic urban water cycle concepts are increasingly called upon for integrated analysis of urban water systems to mitigate water stress in large urban agglomerations. However, integrated analysis is frequently not applied due to the inherent complexity, limitations in data availability and especially the lack of guidelines and suitable software tools. The paper presents the application of the total urban water balance model UVQ to the City of San Luis Potosi (1.2 Mio inhabitants) under the arid conditions of Northern Mexico. UVQ is a lumped parameter model which describes water and contaminant flows from source to sink in urban areas and includes all water types such as rainwater, imported water, surface runoff, wastewater and groundwater. The results were especially useful for spatially explicit groundwater recharge calculation in urban areas. A range of urban water scenarios, including different supply strategies and the effect of externalities such as demand change, were simulated and compared to a calibrated baseline scenario. The analysis demonstrated that shallow urban groundwater resources can substantially mitigate problems of water scarcity and overexploitation of deep aquifers if appropriate water quality protection or fit-for-use paradigms are put into place. The modelling exercise delivers relevant information for the decision 240 S.E. Martinez et al. making process and identifies the most relevant shortcomings in current monitoring systems. This represents a key step on the path to water sensitive and sustainable urban development, including the urban aquifers which have been neglected in the management policy of most cities of the Mexican arid zone.

In particular in arid regions the reuse of waste water and aquifer recharge is an important issue. Elimination of persistent emerging pollutants represents a key factor in integrated water resources management, and identifying suitable treatment processes to eliminate such compounds becomes inevitably necessary. It is the objective of this study (1) to assess the occurrence of emerging pollutants in the Jordan Valley and (2) to review and examine the biodegradability of selected key compounds. Among the most frequently detected compounds during a sampling campaign in 2007 were pharmaceutical residues such as carbamazepine, diclofenac, or naproxen, and X-ray contrast agents such as diatrizoic acid and iopromide, all typically found in Europe and the USA as well. To gain further insight into elimination processes, biodegradation studies were conducted with batch tests and flow-through soil columns under unsaturated, aerobic conditions. Results demonstrated biodegradation for pharmaceutical residues such as ibuprofen, diclofenac and bezafibrate. The degradation rate was faster in treated waste water as compared to raw waste water, most probably due to competing substrate consumption in raw waste water. The antiepileptic carbamazepine showed no degradation in the batch tests and only moderate removal during soil passage, probably due to sorption. The results of this study and previously published data emphasize the need for further studies under more defined conditions to elucidate the specific conditions under which biodegradation of emerging pollutants proceeds.

No abstract