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Title: Anaerobic digestion of liquid wastewaters from food industry using continuously stirred tank reactors
Author: Hu, Windy Chiung Wen
ISNI:       0000 0004 2701 3717
Awarding Body: The University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2001
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This thesis describes an investigation on the application of anaerobic contact process treating a variety of wastewaters from food industries (raw molasses, purge wastes, ice-cream and diary wastewaters). The raw molasses is one of the wastes produced from the sugar industries, which contains high concentrations of organic matters and high concentrations of sulphate and was firstly investigated in this work. A series of batch experiments were carried out to establish a suitable feedstock for pilot scale digesters. A 1% mass molasses medium with a COD: N: P ratio of 200: 5: 1 in a buffer system has been shown to give a successful digestion of molasses with a methane yield of 0.36 l/g CODrem and a COD removal of 89 % from the batch experiment 3. Two pilot scale digesters (14.13 1) were fed with the molasses medium that was established from the batch experiment 3 as suitable for this work. Several organic loading rates were investigated. After feeding with the molasses medium for about 30 days, both pilot digesters have reached steady-state conditions with respect to a COD removal in excess of 90 % and methane yield in excess of 0.321/g CODrem. The process kinetics of anaerobic contact reactor for treating four different wastewaters was investigated. The Monod equation and the Contois equation were used to develop two basic steady-state models. The kinetic parameters required for the application of the steady-state models were determined by using the results obtained from four individual experiments for treating four different wastewaters. Both models were evaluated with four experimental results obtained in this work and a set of routine analysis data obtained from a full scale anaerobic contact reactor treating the ice-cream wastewater for Birds Eye Walls Ltd., (Gloucester). It is found that the Contois model would be more suitable than the Monod model for express the process kinetics of the anaerobic contact process in full scale due to the reason that the Contois model considers the effect of variable influent substrate concentration into the prediction. In addition, the Contois model was found to be better than the Monod model to express the process kinetic when treating the wastewater containing the organic matters, which has a slow rate of hydrolysis (i. e. lipids/proteins).
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available