Screening Of Photosynthetic Bacteria Group And Study On Its Hydrogen Production Factors From Swine Manure Wastewater

This paper is a series research supported by national "863" plan. People confront two serious problems of energy shortage and environment pollution nowadays. It's urgent to develop renewable clean energy. Hydrogen was thought the best substitute for fossil energy as it's high energy density, renewable and burning without pollution. Biological hydrogen was thought being most potential among all hydrogen production methods as it's mild production conditions (normal temperature, Pressure and pH value) and low cost (use industry and agriculture waste as material). Photosynthetic bacteria (PSB) have many special characteristics such as decompose lots of organic to produce hydrogen without oxygen release, high material and light conversion efficiency, high production purity, wide answer range of sun light spectrum and can coexist with different microorganism to set up a good system. PSB hydrogen production with sun light play important role among biological hydrogen production technology.It's the only way to realize industry biological hydrogen production that reduce cost, enhance convention efficiency, provide stable production system. Now most photosynthetic hydrogen production research using glucose, malate , lactate, acetate and so on as hydrogen production material lead high cost. This paper mainly focus on photosynthetic hydrogen production technology from hog manure to reduce cost as well as treating environment pollution. It has two advantages at the same time. Characteristics of strains used were the most important factor that affect material and light conversion efficiency. In this paper the problem of hydrogen production with using pure strain from reports was resolved , strain screening were carry out systematically, hydrogen production directly with non-sterilized material was realized, difficulties of screening advantage hybrid strain and study it's hydrogen production technology lying in the process of biological hydrogen production industrialization were resolved preliminary. Main research result of this paper as following:1. 24 typical samples from 6 representative places at different seasons werecollected according their ecological and physiological characteristics of four kinds of PSB. Mediums and culture conditions accordingly were designed according their ecological and physiological characteristics of the four kinds of PSB including medium ingredients, pH value, light intensity, illuminate time and cycle, temperature, anaerobic condition . Enrichment and isolation of PSB widely were carried out. 33 PSB strains were isolated. Utilization abilities of hog manure, small molecule organic acid and glucose were studied . Strains with good utilization abilities of these materials were screened out as preliminary screening results. Hydrogen production experiment with acetate, propianate and butyrate were carried according these three acetate were the main ingredient resulting from hog manure pre-treatment. 7 strains were selected. Hydrogen production with the mix-culture of these 7 strains were studied according multi-culture had the advantage of better material utilization ability. The result proved that hydrogen productivities of the mix-culture of the 7 advantage strains from acetate, propianate and butyrate were 1590mlH2/g acetate, 2130mlH2/g propianate and 2520ml H2/g butyrate respectively, which were higher than most pure cultures. The productivity were 95.7%, 90.6% and 89% of their theory highest productivity. It proved that mix-culture of the advantage strains selected has high material conversion efficiency.2. Hydrogen production factor of efficiently hydrogen production PSB group (EPSBG) were studied with glucose as substrate according the affecting theory of hydrogen production and low cost requirement in industry production process. Anaerobic and illumination were required during hydrogen production with EPSBG The best hydrogen production conditions of EPSBG were as following: 2000-60001x illumination, 28-34 °C temperature, 5-8 pH value, 10-100% inoculation, nitrate addition has little influence on hydrogen productivity. This prove that hog manure has good industry applying prospect as hog manure has high nitrate concentration.3. Hydrogen production theory research discovered that EPSBG stopped growth during hydrogen production. There exit big difference from most PSB hydrogen production research. This showed that EPSBG had special hydrogen production theory and ways.4. Effects of different hog manure treatment methods on EPSBG hydrogen production were studied according physiological characteristics of EPSBG Dark aerobic treatment was found the best method. Hydrogen productivity with 4 days dark aerobic treatment was 24.1 times than the contrast group of glucose liquid. Smallmolecule organic aced test result of 4 days dark aerobic treatment showed that the concentrations of acetate and other 8 acids increased notably after treatment. The best technological conditions of hog manure dark aerobic treatment as following: 20-35 *C, 50% inoculation , 4cm high hog manure input with triangle bottle in the lab and natural pH value.5.Effects of main technological parameters and different cross-linking agents treatment of EPSBG immobilization by alginate calcium on hydrogen production were studied according to the aim of reducing cost, simplifying control, and improving photo-bioreactor efficiency. The results showed that the immobilized cell was more stable than separate cell and showed longer hydrogen production activity. Four different cross-linking agent showed notable influence on activity and stability of immobilized cell. Dealing with polyacrylamide and glutaraldehyde showed best. Glutaraldehyde concentration of 0.7%, 10:3 ratio of alginate sodium to cell weight(dry) were determined best parameter, and also proved that reducing the size of immobilization cell lead to higher hydrogen productivity. Additional hydrogen of 94.7% of 5mm grain were reached comparing to 3mm grain. 51% cell activity and 75 days stable hydrogen production of immobilized cell were obtained.6.Batch and continuous enlarge hydrogen production experiment were carried out in a 7L photo-bioreactor with the immobilized EPSBG from pre-treatment hog manure with 5000mg/L TCOD. Following result were reached: in batch process, hog manure contain 0.1% glucose started hydrogen production 3-6h earlier and ended 96h later than that only contain 0.1% glucose(contrast group); hydrogen productivity were 10.7 times than contrast group, hydrogen production rate of hog manure was higher than contrast group also; the highest rate of hog manure and contrast group were 34.72 mL.h"1.L1and 3.47mL.h'1.L1 respectively; the average rate were 24.4 mL.lf'.L1 and 1.5 mL.h^.L1 respectively. TCOD remove rate study showed that batch and continuous process were 95.8% and 80% respectively, as well as hydrogen conversion efficiency of two group were 315mL/gTCOD and 300mL/gTCOD respectively. Study on pH value change regulation in batch process showed that pH value was more stable in hog manure substrate , and pH value of hog manure dropped from 6.5 to 5.0 , however, pH value of contrast group dropped from 7.5 to 3.98. This showed that hog manure hog manure had the ability of pH equilibrium. Effect of the dominate parameter of continuous process dilution ratio on hydrogen production rate, pH value of hydrogen production system and TCOD remove ratio were determined in this paper,...