There are more than 30 000 urban wastewater treatment plants in the EU. Some 80% of these have secondary treatment processes using activated sludge. An increase in the toxic load of urban wastewater reduces the cleaning capacity of the bacterial culture. Such increases come from uncontrolled discharges with excess toxic loads and are often seasonal, coinciding with activities of certain industrial processes such as wine production or the canning sector.

When a treatment plant operator detects that the organic or nutrient removal performance is decreasing, most of the biomass has already been damaged; the usual procedure to resume normal activity consists of increasing the air supply to the bioreactor, with a consequent increase in energy consumption and costs. Depending on the type and size of the process, aeration systems may account for about 50-70% of a plant’s total energy consumption.

In May 2016, wastewater treatment plants at Pinedo and Quart-Benàger in Spain suffered non-identified spills which seriously affected the microbiological communities of their activated sludge treatment systems for more than a month. This led to the discharge of wastewater that exceeded legal limits into the Albufera National Park, part of the Natura 2000 network of protected areas, and the Mediterranean Sea. In particular, the events affected the flooding schedule of the park’s rice fields.

Life BACTIWATER aims to demonstrate an innovative and more energy-efficient solution to reduce the environmental impact of failures and malfunctions of biological units after unexpected spills. For this, the project will demonstrate an innovative biological treatment, consisting of the culture and inoculation of microbial communities specially selected to speed up the recovery of the treatment process when disrupted by uncontrolled spills. Tests will be carried out at a demonstration plant, in which the microbial communities developed in the laboratory will be inoculated and different types of scenarios will be tested. A protocol will then be developed for recovering the biological process after a failure event involving the death of microorganisms. The system proposed by the project has high potential for replication.

The specific project objectives are to:

• Validate a diagnostic kit for an early detection of biological failures in wastewater treatment plants: it will reduce the need to restore biological systems due to late detection of spill effects in microorganisms, avoiding additional energy consumption in aeration to recover and stabilise the systems;
• Demonstrate a corrective biological system for when treatment plants fail that will reduce the time and energy needed for recovery;
• Develop a standardised preventive protocol for early detection of biological failures in order to optimise recovery of treatment processes in any wastewater treatment plant;
• Promote the use of novel “omic” tools, as reference diagnostic methodologies in wastewater treatment control. Omic tools are aimed at the universal detection of genes (genomics), mRNA (transcriptomics), proteins (proteomics) and metabolites (metabolomics) in a specific biological sample;
• Reduce energy consumption in the regeneration process, in line with the European target of a 20% increase in energy efficiency by 2020;
• Carry out an economic and environmental assessment of the use of enhancer microorganisms at the demonstration plant;
• Develop a business plan for future commercialisation of the project’s outputs; and
• Disseminate and transfer the project product.

The project is fully in line with the Urban Waste Water Directive and its objective of protecting the environment from the adverse effects of wastewater discharges. The project will also contribute to the implementation of the Water Framework Directive, the goal of which is a good status for all EU water bodies.

Expected results:

• 20% reduction in recovery time. The artificial population enhancement of a biological system allows the initial or lag phase of bacteria growing to be reduced, or even eliminated, introducing the bacteria in an exponential growing phase;
• 20-22% reduction in energy consumption in the recovery process;
• Anticipation of 20% of biological failures;
• An improved nitrification process in wastewater treatment plants that works at low temperatures;
• A reduction in the discharge of pollutants to natural water bodies during treatment plant failures;
• A decision-support system (database of spills) based on compiled historical data of the causes and effects of spills, pollution events and preventive protocols; and
• An action protocol for biological failures across Europe, including legal and process guidelines to be extrapolated to any wastewater treatment plant in the EU.