Quantitative image analysis for the characterization of microbial aggregates in biological wastewater treatment: a review

• Published in: Environmental science and pollution research international 2013-09, Vol.20 (9), p.5887-5912
• Main Authors: Costa, J. C., Mesquita, D. P., Amaral, A. L., Alves, M. M., Ferreira, Eugénio C.
• Format: Article
• Language: English
• Subjects: Activated sludge; Aggregates; Anaerobic digestion; Anaerobic microorganisms; Anaerobic processes; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Automation; Bioengineering; Biological; Biological wastewater treatment; Biotechnology; Chemical oxygen demand; Chemometrics; Computer applications; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental studies; Filamentous bulking; Fixed bed reactors; Flocculation; Focusing; Granulation; Image analysis; Image processing; Image Processing, Computer-Assisted - methods; Lasers; Metazoa; Microorganisms; Microscopy; Monitors; Morphology; Principal components analysis; Process control; Process controls; Review Article; Science & Technology; Sludge; Sludge volume index; Studies; Trends; Waste Disposal, Fluid - methods; Waste Water Technology; Wastewater treatment; Water Management; Water Microbiology; Water Pollution Control; Water treatment
• ISSN: 0944-1344; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-013-1824-5

Quantitative image analysis techniques have gained an undeniable role in several fields of research during the last decade. In the field of biological wastewater treatment (WWT) processes, several computer applications have been developed for monitoring microbial entities, either as individual cells or in different types of aggregates. New descriptors have been defined that are more reliable, objective, and useful than the subjective and time-consuming parameters classically used to monitor biological WWT processes. Examples of this application include the objective prediction of filamentous bulking, known to be one of the most problematic phenomena occurring in activated sludge technology. It also demonstrated its usefulness in classifying protozoa and metazoa populations. In high-rate anaerobic processes, based on granular sludge, aggregation times and fragmentation phenomena could be detected during critical events, e.g., toxic and organic overloads. Currently, the major efforts and needs are in the development of quantitative image analysis techniques focusing on its application coupled with stained samples, either by classical or fluorescent-based techniques. The use of quantitative morphological parameters in process control and online applications is also being investigated. This work reviews the major advances of quantitative image analysis applied to biological WWT processes. The authors acknowledge the financial support to the project PTDC/EBB-EBI/103147/2008 and the grant SFRH/BPD/48962/2008 provided by Fundacao para a Ciencia e Tecnologia (Portugal).