This degree thesis studied the viability of treating molasses waste water using a combination of chitosan and activated carbon. Chitosan is obtained by deacetylation of chitin and is an important polymer in water treatment. Activated carbon is a powerful absorbent that is used in filtration. Effects of temperature, time, oh and agitation was studied. The research pointed important leads to embracing chitosan in waste water treatment.
Kenya is a major sugar producer with a sugar production output of 591,658 tonnes. The sugar industry encompasses sugar refining which yields molasses used in molasses distilleries to produce ethanol. The molasses distillery produces distillery waste known as spent wash which has a high BOD/COD, bad odor and brown color. The high BOD/COD can be removed by conventional means such as aerobic and anaerobic digesters, but it is this brown caramelized compounds known as melanoidins that must be removed by unconventional means since they are recalcitrant and difficult to biodegrade biologically. This project aims to explore
options of removing recalcitrant compounds in molasses waste water by adsorption process using powdered activated carbon and chitosan a biopolymer derived from chitin.
Sugarcane molasses is the by-product of the sugar production industry which are generated during sugar production. Sugarcane molasses contains 50% fermentable sugar is dark brown, putrid and viscous liquid. Sugarcane molasses is a feedstock for ethanol production and is used in a ratio of 1:1 for fermentation and purification of spirit. The product collected as bottom products form spent wash which is the major constituent of molasses waste water. Properties of molasses include high acidity, strong odor, coloring pigments due to presence of melanoidins, metal sulfides and phenolics giving it brown color. Spent wash is one of the serious pollution problems of countries producing alcohol from fermentation and subsequent distillation of cane molasses. According to distillery spent wash is characterized as one of the caramelized and recalcitrant wastes containing extremely high Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), inorganic solids and low in pH 1-2. The post methanation distillery effluent produced from treatment is characterized by high BOD, COD, intense brown colour due to presence of melanoidin pigments and high levels of salts and nutrient rich.
Table of Contents
1 INTRODUCTION
1.1 Overview
1.2 Physical Chemical Characteristics of molasses waste water
1.3 Problem statement
1.4 Objectives
2 LITERATURE REVIEW
2.1 MOLASSES
2.2 USES OF MOLASSES
2.3 Molasses waste water pigments
2.4 Post treatment methods for spent wash
2.5 Chitosan
2.6 Adsorption kinetic models
2.7 Equilibrium Isotherms
2.8 Derivation of freundlich equation
2.9 The Langmuir isotherm
2.10 Chitosan Biosorption
2.10.1 Sorption process on chitosan biopolymer
2.11 Powdered Activated Carbon
2.12 Types of Activated Carbon
3 Methodology
3.1 Apparatus and Reagents
4 Experimental Results and Analysis
4.1 Calibration Analysis
4.2 Contact Time Comparison
a) Activated Carbon Data
4.3 Adsorbent Dose Comparison
a) Activated Carbon Data
4.4 PH Comparison
4.5 Concentration of Molasses Waste Water
4.6 Combination Dose
4.7 ADSORPTION ISOTHERM
4.8 Freundlich Isotherm;
4.9 Langmuir Isotherm
4.10 Freundlich Isotherm;
4.11 Langmuir Isotherm
5 Conclusion and Recommendation
Project Objective and Scope
The primary objective of this research is to evaluate the effectiveness of using a combination of chitosan, a biopolymer derived from chitin, and powdered activated carbon as an adsorbent to remove recalcitrant melanoidin pigments and reduce Chemical Oxygen Demand (COD) in molasses wastewater, which cannot be efficiently treated by conventional aerobic or anaerobic systems.
- Characterization of physical and chemical properties of molasses wastewater.
- Development of a bench-scale testing protocol to simulate full-scale treatment.
- Comparative analysis of adsorption efficiency for individual and combined adsorbents.
- Determination of optimal parameters including contact time, pH, and adsorbent dosage.
- Optimization of the mixing ratio between chitosan and powdered activated carbon.
Excerpt from the Book
Melanoidin
Melanoidin is formed by Maillard reactions which are initiated by condensation of an amine with a carbonyl group, often from a reducing sugar. The structural determination of melanoidines has remained a challenge for several years. A wide range of reactions takes place in the formation of melanoidin and include cyclizations, dehydrations, retroadolizations, rearrangement and further condensations, leading to formation of brown co polymer. The melanoidins formed are recognized as being acidic in nature. As reaction time and temperature increases, total carbon content increases, thus promoting the unsaturation of molecules. The colour intensity increases with the polymerization degree, as measured via absorbance spectrometer.
Summary of Chapters
1 INTRODUCTION: This chapter provides an overview of the molasses production industry in Kenya, highlights the environmental challenges posed by the discharge of high BOD/COD molasses wastewater, and defines the problem statement and objectives of the project.
2 LITERATURE REVIEW: This section covers the chemical properties of molasses, the various pigments causing discoloration, and reviews existing biological and physical-chemical treatment methods, with a focus on chitosan biosorption and powdered activated carbon.
3 Methodology: This chapter details the apparatus used, the preparation of the molasses waste water samples, and the specific procedures for deriving chitosan from fish scales and setting up the adsorption experiments.
4 Experimental Results and Analysis: This section presents the empirical data gathered from laboratory testing, including calibration curves, the influence of contact time, adsorbent dosage, pH levels, and the performance of combination dosing strategies.
5 Conclusion and Recommendation: This chapter summarizes the experimental findings, confirming the feasibility of using a chitosan-powdered activated carbon combination, and provides insights into the optimal operating conditions for effective color and COD removal.
Keywords
Molasses wastewater, Chitosan, Powdered Activated Carbon, Melanoidins, Adsorption, COD reduction, Distillery spent wash, Biosorption, Langmuir isotherm, Freundlich isotherm, Wastewater treatment, Bio-polymer, Decolorization, Adsorbent dose, pH sensitivity
Frequently Asked Questions
What is the core subject of this project?
This project investigates the treatment of distillery molasses wastewater, focusing on the removal of recalcitrant pollutants like melanoidins that are resistant to conventional biological treatment.
Which materials are used for the wastewater treatment?
The study utilizes a combination of powdered activated carbon and chitosan, a biopolymer derived from fish scales, as adsorbents to remove pollutants.
What is the main goal of the research?
The aim is to develop a cost-effective adsorption-based treatment method that reduces color, bad odor, and high chemical oxygen demand (COD) in distillery effluent.
Which scientific methodology is applied?
The research uses a physical-chemical adsorption method, testing various experimental parameters such as contact time, adsorbent dosage, pH, and sample concentration in a laboratory setting.
What does the main part of the report cover?
The main section provides a comprehensive literature review followed by detailed experimental procedures, raw data analysis, and the evaluation of adsorption isotherms to model the efficacy of the materials.
Which keywords characterize this work?
Key terms include molasses wastewater, chitosan, powdered activated carbon, melanoidins, adsorption, COD reduction, and wastewater treatment.
Why is chitosan considered a viable alternative to activated carbon?
Chitosan is a biodegradable, value-added product derived from crustacean and fish waste. It is significantly cheaper than activated carbon, making a combination of both materials an economically attractive treatment solution.
What were the findings regarding the optimal pH for adsorption?
The experiments demonstrated that the optimum pH for both chitosan and activated carbon in this study was pH 3, with higher pH values leading to a reduction in adsorption capacity.
What was the conclusion regarding the combination of adsorbents?
The study concluded that an optimum dosage ratio of 1:1 for chitosan and activated carbon yielded an 80% removal efficiency, demonstrating the potential for substituting expensive activated carbon with chitosan.
- Quote paper
- Humphrey Mutuma (Author), 2016, Treatment of Molasses waste water using chitosan and activated carbon. Waste water treatment, Munich, GRIN Verlag, https://www.grin.com/document/978589
