טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentMerom-Jacov Osnat
SubjectInvestigation of Disturbances to Separation and Dewatering
of Suspended Bio-Solids in Biologicl Treatment
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Emeritus Noah Galil (Deceased)


Abstract

Activated sludge is the most common biological process for wastewater treatment, while solid-water separation is one of the most problematic mechanisms. The sludge dewaterability is significantly affected by environmental conditions.

This investigation examined the influence of pollutant shock loading at different concentrations under different sludge residence time (SRT) conditions. The correlation between parameters which characterize the activated sludge process and influences exerted by specific organic pollutants, could improve the understanding of field problems and could provide sustainable solutions.

This research focused on the water distribution in sludge, according to the water types defined in the literature, as influenced by the exposure to either Phenol or Diesel fuel shock loadings. The biological process efficiency was characterized by common parameters including the treated water quality, the settling characteristics of biosolids, the settled sludge characteristics in terms of specific resistance to filtration and water distribution, and the bio-flocs properties (extracellular polymers (ECPs) matrix, free ECPs, surface charge).

The study indicated that external pollutants worsened the treated water quality and the settling characteristics (SVI), lowered the water releasing ability and changed the water distribution. Partial explanation to these symptoms could be provided by the surface charge of the biosolids and the composition of the ECPs matrix. The SRT played an important role in the presence of external pollutants. According to these evidences further research is needed, focusing on the water releasing ability and on physical-chemical properties, in order to have the ability to connect between the symptoms and the cause to those problems.