Risks for groundwater contamination from domestic waste water: tracers, model applications and quality criteria

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.