BLENDING PROCESS FOR SLUDGETHICKENING

Abstract

The objective of this thesis is to study the blending process as a method for increasing the efficiency of the gravity thickener. The problem is that in Egypt in many wastewater treatment plants the gravity thickener efficiency is lower than expected, the solids outlet is lower than expected especially when the primary and secondary sludge are mixed together. In this thesis, the blending method using dilution water (effluent water from Al Gabal Al Asfar wastewater treatment plant) before thickening to increase the efficiency of the gravity thickener was studied. The thesis shows that the blending by addition of dilution water to the mixed sludge is not suitable for the sludge produced in this wastewater treatment plant. In addition; the results shows that there is no increase in the thickening efficiency with the addition of the dilution water. The thesis studied three different mixing ratios between the primary and secondary sludge 2:8, 4:6 and 3:7 (the actual ratio in the WWTP) and found that the ratio 4:6 gives the best thickening efficiency. The results explained that it is not suitable to increase the retention time in the gravity thickener when the primary and secondary sludge are mixed together and when the dilution water is added to them. SUPERVISORS Prof.Dr. Mohamed El Hosseiny El Nadi, Associate Prof. Dr. Mohamed Sobhy Abd El-Rahman, Assistant Prof. Dr. Sayed Ismail Ali Ahmed. KEY WORDS Wastewater Treatment, Sludge Treatment, Gravity Thickener. TABLE OF CONTENTS COVER Page APPROVAL COMMITTEE ii DEDICATION iii STATEMENT iv ACKNOWLEDGMENTS v ABSTRACT vi TABLE OF CONTENTS vii LIST OF FIGURES x LIST OF TABLES xiv CHAPTER I : INTRODUCTION 1.1. BACKGROUND 1 1.2. STUDY OBJECTIVES 2 1.3. SCOPE OF WORK 2 1.3.1. THEORETICAL PART 2 1.3.2. EXPERIMINTAL PART 3 1.4. THESIS ORGANIZATION 3 CHAPTER II