Risk management

Risk management according to EN 15975-2

In the update to the WHO guidelines for drinking water quality, WHO recommends implementing a Water Safety Plan (WSP). The Water Safety Plan is based on the HACCP concept, a process-oriented risk management system. The systematic procedure to set up such a system is described in EN 15975-2 “Security of Drinking Water Supply”. We support water supply companies to set up this type of risk management system. The project steps are taken in close consultation with the relevant supply companies and adapted in their scope and level of detail to the local requirements.

Water protection and agricultural land use

Nitrate is a common contaminant of groundwater resources. We record nitrate leaching by monitoring soils and groundwater, evaluate it using simulation models, and devise remediation concepts. These are often linked to energy generation from biomass and biogas. Our efforts are aimed at establishing a water-protective land management in drinking water catchment areas and thereby reduce the nitrate leaching or entry of pesticide residues (active substances and metabolites).

Groundwater monitoring and databases

Monitoring raw water resources is useful to sustainably ensure drinking water quality in the long term. To that end we conduct area and problem-specific monitoring programmes and optimise measurement networks. The data is evaluated in more detail using statistical methods, geographic information systems (GIS), interpolations or groundwater modelling methods.

Transregional databases maintained by TZW on groundwater and raw water quality provide a quality-assured and validated database. This can then be used to prepare recommendations for action and targeted measures in the event of lower-quality drinking water.

Further information on the Raw Water Database Water Supply Pesticides (RWDB) can be found on the project page. For water suppliers, there is direct access to the online portal here (access data required) and a brief guide to it.

If you are interested in the Groundwater Database Water Supply Baden-Württemberg (GWD-WV), you can access the website www.grundwasserdatenbank.de here.

Construction measures in drinking water protection areas

Construction and infrastructure measures generally disturb the subsoil, which reduces the thickness of the surface layer. Construction activities can cause turbidity, microbiological or other contamination of the groundwater, for example due to accidents with water-polluting substances. We evaluate the potential hazards caused by construction site equipment, the building measures and the subsequent operation of the building, and derive a list of relevant measures to preserve evidence, protect the groundwater and secure the water supply. In these matters we collaborate closely with the relevant water supply companies, the competent authorities and the planners.

Preparation of schedules of measures and action plans

According to Section 16 (5) of the German Drinking Water Ordinance, every water supply company is obliged to create a schedule of measures that considers the regional water supply conditions. It is particularly recommended that water supplies without continuous disinfection also create action plans based on the DVGW worksheet W 1020 in addition to a schedule of measures. These contain rules on what to do if microbiological limits are exceeded with the aim of supplying consumers hygienically flawless drinking water at all times without any restrictions on use.

Identification of faecal contamination sources (microbial source tracking)

The microbiological culture procedures used for quality control currently are ideal for detecting quality problems caused by faecal entry, however they provide no information on the origin of this contamination. This information is vital for implementing targeted protection measures, for instance, as part of the Water Safety Plan. New, predominantly molecular biological methods have the potential to relate the origin of faecal input to possible sources.

Cause analysis for non-compliance of microbiological limit values in drinking water

Microbiological problems in drinking water can have a variety of causes. TZW offers consultation for water supply companies, authorities, industry and other partners on microbiological limit breaches and hygienic problems in drinking water treatment, distribution and installation.