PROJECT DESCRIPTION
BACKGROUND
The EU has more than 30 000 urban wastewater treatment plants, the majority of which (80%) use activated sludge in secondary treatment processes. 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 and the canning sector.
By the time 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 for resuming 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 that 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.
OBJECTIVES
The project, Life BACTIWATER, aimed to demonstrate an innovative and more energy-efficient solution for reducing the environmental impact of failures and malfunctions of biological units after unexpected spills. It planned to 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 would be carried out at a demonstration plant, in which the microbial communities developed in the laboratory would be inoculated and different types of scenarios tested. A protocol would then be developed for recovering the biological process after a failure event involving the death of microorganisms. The system proposed by the project would have a high potential for replication.
Specifically, the project aimed to:
- Validate a diagnostic kit for the early detection of biological failures in wastewater treatment plants (such a kit would 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 aim to detect 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 EU’s target to increase energy efficiency by 20% by 2020;
- Carry out an economic and environmental assessment of the use of enhancer microorganisms at the demonstration plant; and
- Develop a business plan for future commercialisation of the project’s outputs.
The project aimed to contribute towards the Urban Waste Water Directive, especially the objective of protecting the environment from the adverse effects of wastewater discharges. The project would also contribute to the implementation of the Water Framework Directive, the goal of which is a good status for all EU water bodies.
RESULTS
Through the application of biotechnological products, the LIFE BACTIWATER project helped improve the recovery of the biological process of wastewater treatment plants (WWTPs) affected by uncontrolled and/or seasonal spills received in the influent, and thus helped protect the environment from improperly treated wastewaters. The project created two inocula composed of different bacterial species, and an early detection kit based on key microorganisms found in WWTPs as indicative of the health of the biological process. The heterotrophic inoculum was especially effective in treating spills with high chemical oxygen demand (COD) values. It was also shown to be suitable for use in smaller WWTPs, which are commonly less resilient to spills. However, the autotrophic inoculum was not shown to be effective in project testing, although the beneficiaries say that they are continuing to optimise its use.
As a first step, the project created a database of previous spills registered in the WWTPs of Valencia and Alicante provinces. It then carried out analysis of samples from six WWTPs to gather data on existing bacteria in those plants. This research formed the basis for developing the microbial enhancers based on seven selected microorganisms. Their optimal growing conditions were defined, while the team also grew pure strains of the microbial enhancers to be used during the pilot plant testing phase. They then tested the end-product, heterotrophic inoculum, in two small WWTP. These sites, which are managed AVSA, were chosen because they are continuously affected by high organic load spills. The results of the tests were very satisfactory.
The project demonstrated that using the heterotrophic inoculum reduces the amount of energy required to remove COD by 22% in terms of weight of COD and by 13% in terms of treated wastewater. The use of the inoculum also lowers the amount of ammonium by 97%.
Results also indicate, however, that the use of the inoculum ceases to be a cost-effective solution in WWTP that serve populations of greater than 15 000 population due to the higher amounts of inoculum required. But the early detection kits do not have such limitations. The basic version of the kit quantifies the total amount of bacteria and fungi and is designed for the general monitoring of a plant’s performance, while the more expensive ‘standard’ version is used for specific applications, identifying 16 targets.
The beneficiaries have set an ambitious target of 578 Spanish WWTPs (390 managed by the GOMSL group and 188 by other WWTP managers) using its products by 2024 and 2 800 European WWTPs by 2026. Reaching its sales targets would generate around €122 000 in 2022, €1.2m in 2023, €6.1m in 2024, €18.3m in 2025 and €34.2M in 2026. The inoculum is available fresh, with a higher concentration of bacteria, and lyophilised, which enables it to be stored.
Further information on the project can be found in the project's layman report (see "Read more" section).
