Analysis of Changes of Particle Size Distribution and Biological Composition of Flocs in Wastewater During the Growth of Algae

Abstract

The process of growth of algae can be described using the images from microscopic analysis. The new approach to assessment of the growth dynamics of algae used the data of granulometric composition of liquid medium and the modified Avrami equation relating to the crystallisation process. This paper presents a comparison of both methods (granulometric and microscopic) for the analysis of the dynamics of changes in the growth of algae in wastewater. The experimental set-up consisted of four glass tanks filled with biologically treated sewage, in which algae grew. The cultivation of algae was carried out for 8 weeks. During this period, the granulometric analysis and microscopic observations of sewage were conducted. The study demonstrated that with increase in the size of flocs in treated sewage, biomass of algae was also increased. Therefore, the results obtained with the method of laser diffraction are in agreement with microscopic observation of flocs. Granulometric analysis could be, next to microscopic analysis, a method for the estimation of the dynamics of changes in the growth of algae in sewage. This knowledge will allow to selection of a suitable method of wastewater treatment and algal separation.

Particle size distribution as a major characteristic of domestic wastewater: implications for the modeling and design of membrane bioreactors

“…While these methods provide useful information for the specific cases of interest, they do not relate to sewage mainly because their results do not match with the currently implemented COD fractionation and also with the model components in process modeling, except for the laser diffraction method, which was used in a few cases to characterize the PSD of particulate matter in sewage. 35,56,57 Conceptual significance of colloidal and soluble substrate The mechanism of organic matter removal was not fully clarified long after the recognition of the biological nature of the process. 2 The observation of the rapid removal of colloidal matter in sewage suggested that adsorption was the major mechanism.…”

Application of microalgae cultivated on pine bark for the treatment of municipal wastewater in cylindrical photobioreactors

“…At that time, microalgae ( Ulothrix tenerrima , Microthamnion kuetzingianum , Klebsormidium sp., Tribonema sp.) grown in the wastewater forming flocs settling on the bottom of the tanks or on the surface of the pine bark (Garbowski et al ., 2019). In addition, turbidity in the treated sewage was significantly decreased (in PBR‐A was 2.40 NTU, in PBR‐B was 1.78 NTU) compared to the control sample (95.0 NTU).…”

A critical review on applications of the Avrami equation beyond materials science

“…Though the JMAK model was developed to describe the progress of phase transformation in a material system, its application has not been limited to materials science. The model has been used in other fields of research, including life sciences examples such as oncology [35][36][37][38][39][40], ecology [41][42][43][44][45] and epidemiology [46][47][48][49][50]. Some systems from those contexts can be regarded as undergoing a 'phase transformation', and non-thermodynamic driving forces analogous to undercooling and supersaturation can be identified.…”

“…The surface fraction that is colonized by algae follows a sigmoidal curve. Garbowski et al [43] modelled the volume fraction of algal particles having a given diameter in wastewater. The constant k encompasses the rate of nucleation and growth of the particles, and n is related to the geometry of particles.…”