Experimental Research On High-concentration Acclimation Of Activated Sludge And The Progress In The Efficiency Of Hydrogen-producing

Hydrogen is considered to be an ideal and clean source of energy in the future. Among the many processes of hydrogen production, microbial hydrogen production as an environmentally friendly and energy saving process, has been extensively being investigated especially in pure culture techniques.The present study is an attempt to produce hydrogen from sucrose by anaerobic fermentation of acclimated sludge. The distinct increase of sucrose consumption rate and hydrogen evolution efficiency of different sources sludge was observed through the batch acclimation of high concentration of sucrose medium. The molar yield of hydrogen at 76-84g/L of initial concentration of sucrose medium was more than that of low concentration about 40g/L. The sucrose consumption rate of brew-house sludge, brew-house discharged sludge and Nanjing city drain sludge was near 85%. The yield of hydrogen production of these three kinds of sludge was 2.24, 2.35 and 2.14 molH₂/mol sucrose, respectively. This is the first to our knowledge reported for the batch acclimation of sludge at high concentration of organic matter medium over 80g sucrose per liter. The progress in sucrose consumption rate and hydrogen production efficiency during batch acclimation of sludge was elucidated. The notable improve of the unit treatment capacity of acclimated sludge was obtained.The main focus of this study was effective hydrogen bio-production using sucrose medium as the simulated organic wastewater. The improvement of sucrose metabolism rate and hydrogen evolution efficiency was achieved through batch acclimation from low-concentration to high-concentration of sucrose. The conditions of anaerobic fermentation of batch acclimated sludge were investigated. The optimized medium for anaerobic fermentation contains 90g/L of sucrose, 8mL/L of corn liquid steep, 20mg/L of FeSO4·7H₂O, 10mg/L of MgCl₂·6H₂O and 1.0g/L of K₂HPO₄. The medium was adjusted to pH5.0. Optimized fermentation temperature was 36°C. The maximum hydrogen evolution rate at optimized conditions was 565 mLH₂/L·h, which was 223% higher than that at the initial conditions; The yield ofhydrogen was 3.04molH2/mol sucrose, which was 30% higher than that at the initial conditions. The efficient medium which supplied organic nitrogen and growth cofactor simultaneously was suggested. This medium is of considerable economic significance for practical process of hydrogen bio-production of sludge anaerobic fermentation.The ethanol type fermentation was obtained with the change of anaerobic fermentation type, through studied the changes of main liquid fermentative products, sucrose metabolism efficiency, hydrogen yield and microbe relation in acclimation progress of activated sludge. Through studed the change of the predominant flora in ethanol type fermentation by biolog, there was a kind of predominant flora awalys in predominant position in activated sludge's microorganism. The predominant position of two kinds of strain has transformed with acclimation progress of activated sludge. Indicate that acclimation progress of activated sludge selected the predominant anaerobic bacteria of hydrogen production, and made of well pro-hydrogen biogeocenose by microbic ecophysiology.