Increasing aridity, drought, and climate change have brought the need for a more sustainable and efficient use of available water resources into sharp focus within the EU. A key component of ensuring a secure water supply in the long term is water reuse. Highly treated and disinfected wastewater is to be used more extensively for irrigation in agricultural production and in urban areas.

Risk management plays a central role in the reuse of treated wastewater. It must be verifiable that bacteria, viruses, and protozoa are removed to at least specific levels during the treatment process (e.g., 6 log levels = 99.9999% removal). Providing this verification requires a large sample volume and significant costs including high personnel expenses.

To meet these requirements, KWB, in collaboration with its partners Watersam GmbH and the Institute for Hygiene and Public Health at the University Hospital Bonn, is developing, validating, and testing an automated sampler for the enrichment of microbial indicator parameters as part of the AutoProMi project. This sampler is designed to make it easier for wastewater treatment plant operators to validate their treatment processes and regularly monitor the performance of their facilities.

The sampler is designed to:

• collect water samples fully automatically,

• enrich multiple microbial indicators simultaneously, and

• elute these indicators.

As a result, risk management for water treatment can be carried out cost-effectively and with significantly less personnel, even at low influent concentrations.

The project benefits from KWB’s many years of expertise in

• practical aspects of water reuse,

• advanced wastewater treatment processes, including disinfection,

• pilot testing and practical sampling, as well as

• legal and specific requirements for process validation.

The practical applicability of the sampler will be demonstrated under real-world conditions at three different wastewater treatment plants equipped with advanced wastewater treatment (disinfection).

By using the automatic sampler, wastewater treatment plant operators benefit from:

• lower costs

• faster sampling

• easier regular monitoring of the treatment plant’s performance capability.

The project thus provides the fundamental requirements for safe water reuse and supports its implementation in Germany.