Reuse of ultrafiltered effluents for crop irrigation: On-site flow cytometry unveiled microbial removal patterns across a full-scale tertiary treatment

Energy and material refineries of future: Wastewater treatment plants

There have been many important milestones on humanity's long journey towards achieving environmental sanitation. In particular, the development of the activated sludge system can be claimed to be one of the most groundbreaking advances in the protection of both public health and the wider ecosystem. The first wastewater treatment plants (WWTPs) were developed over a century ago and were soon configured for use with activated sludge. However, despite their long history and service, conventional activated sludge (CAS) plants have become an unsustainable method of wastewater treatment. In addition, conventional WWTPs are intensive energy-consumers and at best allow only very limited material recovery. A paradigm shift to convert existing WWTPs into more sustainable facilities must therefore be considered necessary and to this end the wastewater biorefinery (WWBR) concept may be considered a solution that maximizes both energy and material recovery, in line with the circular economy approach.

Treatment of Rose Oil Processing Effluent with Chlorella sp. Using Photobioreactor and Raceway

The integration of treatment of wastewater from agro-based industries with microalgae cultivation can reduce costs associated with cultivation while treating wastewater to meet the discharge limits for chemical quality of irrigation in agriculture and to obtain biofertilizers. Rose Oil Processing Effluent (ROPE) can be utilized as a growth medium for Chlorella sp. and thus can be used for biofertilizer production. The present study is aimed at determining the feasibility of the cultivation of Chlorella sp. in ROPE using a tubular photobioreactor with a capacity of 50 L and a raceway to treat ROPE while consuming less energy. The optimum mixing ratio ([ROPE/(ROPE + Bold Basal Medium (BBM)] × 100) was determined as 50% using 2-L Erlenmeyer flasks based on the COD removal efficiency. Better removal efficiencies with regard to COD, BOD₅, NH₄⁺-N, and NO₃^--N were obtained from the raceway compared to the tubular photobioreactor. The effluents from both systems met the chemical quality of irrigation water. The results of the biomasses harvested from both systems in macro and microelements revealed that they have a potential as a biofertilizer in agriculture. The energetic analysis of the ROPE treatment using the tubular photobioreactor and raceway showed that the raceway system had a better net energy ratio while consuming less energy and producing more energy during cultivation. Overall, the raceway appeared to be a better option to treat ROPE with production of biofertilizer and irrigation water quality while consuming less energy.

Computational Analysis of Microbial Flow Cytometry Data

Flow cytometry is an important technology for the study of microbial communities. It grants the ability to rapidly generate phenotypic single-cell data that are both quantitative, multivariate and of high temporal resolution. The complexity and amount of data necessitate an objective and streamlined data processing workflow that extends beyond commercial instrument software. No full overview of the necessary steps regarding the computational analysis of microbial flow cytometry data currently exists. In this review, we provide an overview of the full data analysis pipeline, ranging from measurement to data interpretation, tailored toward studies in microbial ecology. At every step, we highlight computational methods that are potentially useful, for which we provide a short nontechnical description. We place this overview in the context of a number of open challenges to the field and offer further motivation for the use of standardized flow cytometry in microbial ecology research.

Water and microbial monitoring technologies towards the near future space exploration

Space exploration is demanding longer lasting human missions and water resupply from Earth will become increasingly unrealistic. In a near future, the spacecraft water monitoring systems will require technological advances to promptly identify and counteract contingent events of waterborne microbial contamination, posing health risks to astronauts with lowered immune responsiveness. The search for bio-analytical approaches, alternative to those applied on Earth by cultivation-dependent methods, is pushed by the compelling need to limit waste disposal and avoid microbial regrowth from analytical carryovers. Prospective technologies will be selected only if first validated in a flight-like environment, by following basic principles, advantages, and limitations beyond their current applications on Earth. Starting from the water monitoring activities applied on the International Space Station, we provide a critical overview of the nucleic acid amplification-based approaches (i.e., loop-mediated isothermal amplification, quantitative PCR, and high-throughput sequencing) and early-warning methods for total microbial load assessments (i.e., ATP-metry, flow cytometry), already used at a high readiness level aboard crewed space vehicles. Our findings suggest that the forthcoming space applications of mature technologies will be necessarily bounded by a compromise between analytical performances (e.g., speed to results, identification depth, reproducibility, multiparametricity) and detrimental technical requirements (e.g., reagent usage, waste production, operator skills, crew time). As space exploration progresses toward extended missions to Moon and Mars, miniaturized systems that also minimize crew involvement in their end-to-end operation are likely applicable on the long-term and suitable for the in-flight water and microbiological research.