The anti-epileptic drug carbamazepine was used as marker species in wastewater to identify and quantify sewer exfiltration. In several studies carbamazepine turned out to be hardly removed in wastewater treatment and not or just slightly attenuated during bank infiltration. Concentrations in wastewater are generally 1000 times higher than the limit of quantification. In contrast to many other marker species a "young" drug as carbamazepine is discharged to the environment only by wastewater. The results from this study carried out in Linz, Austria indicate an average exfiltration rate, expressed as percentage of the dry weather flow that is lost on the city-wide scale, of 1%. This rate is lower than sewage losses reported in most other studies which attempted to quantify exfiltration on the basis of groundwater pollution. However, it was also possible to identify one area with significant higher sewage losses.

Monitoring of carbamazepine concentrations in wastewater and groundwater enables us to identify and quantify sewer exfiltration. The antiepileptic drug carbamazepine is hardly removed in wastewater treatment plants and not or just slightly attenuated during bank infiltration and subsoil flow. Concentrations in wastewater are generally 1000 times higher than the limit of quantification. In contrast to . many other wastewater tracers carbamazepine is discharged to the environment only via domestic wastewater. The results from this study carried out in Linz, Austria indicate an average exfiltration rate of 1%, expressed as percentage of the dry weather flow that is lost to the groundwater on the city-wide scale. This rate is lower than sewage losses reported in most other studies which attempted to quantify exfiltration on the basis of groundwater pollution. However, it was also possible to identify one area with significantly higher sewage losses. This method seems to be very suitable for the verification of leakage models used to assess sewer exfiltration on a regional scale.

The antiepileptic drug carbamazepine is a useful anthropogenic marker in groundwater to detect and quantify sewer exfiltration. In 2003 its application on a city wide scale enabled the identification of a trunk sewer in extremely bad structural status with an exfiltration (of wastewater into groundwater) rate in the adjacent area of around 5% compared to an average of approximately 1% in other parts of the city. After a reconstruction of the trunk sewer investigations were carried out again in 2008. Due to the reconstruction a decrease in exfiltration to roughly 3% could be achieved, which equals a reduction of exfiltration by about 45%. Thus carbamazepine emerged as suitable anthropogenic marker to assess sewer exfiltration and to evaluate the success of reconstruction measurements on a regional scale.

In the framework of the Environmental Program for the Danube River Basin financed by the PHARE-program of the EC-Commission the study “Nutrient Balances for Danube Countries” was carried out by the Department of Water and Wastewater Engineering of the Budapest University of Technology and the Institute for Water Quality and Waste Management of the Vienna University of Technology. Expert teams from seven further countries from the Danube Basin completed the team for the project. A crucial part of this study was the evaluation of the present situation of wastewater management of the different countries and the evaluation of future strategies for wastewater management in the context of nutrient balances. This paper presents the developed methodology for wastewater management and the results of its application to the Danube catchment. The major conclusions of the study are: to postpone sewer construction unless hygienic reasons and/or drinking water protection require it and to aim at upgrading treatment efficiency; an ambient water quality principle requires high treatment efficiency in many cases and by introducing nutrient removal at municipal wastewater treatment plants about 20% of the total nutrient emissions to surface waters can be removed.

Infiltration of municipal or domestic waste water happens as unwanted or even planned form of waste water disposal as: infiltration of septic tank effluents, leakage from pits in rural areas, exfiltration from sewer systems and infiltration of biologically treated waste water in regions with lack of receiving surface waters. Suitable markers for domestic waste water in groundwater are boron (low dilution) and carbamazepine (high dilution). Pathogens and oxygen depletion represent the main risk for drinking water quality arising from domestic waste water in groundwater. Even infiltration of biologically very well treated waste water will cause zones in groundwater where drinking water standards cannot be met. The extent of these zones may vary between <20 m and several kilometres from the point of infiltration depending on the local situation.