Qun Hui Wang

On-site production of crude glucoamylase for kitchen waste hydrolysis

Kitchen waste from dining rooms accounts for a considerable proportion of municipal solid garbage, and economical recycle ways are needed to be developed. This study investigated glucoamylase production from kitchen waste and the feasibility of kitchen waste hydrolysis by the crude enzymes produced. The key problems of high water content and poor porosity in kitchen waste for glucoamylase production under solid-state fermentation could be solved readily by the addition of corn stover or paddy husk. As a support medium, corn stover was better than paddy husk. Smashed kitchen waste (sKW) mixed with corn stover in the ratio of 3.75 : 1 (dry basis) produced 1838 U g-1 of glucoamylase by Aspergillus niger UV-60 within 96 h. The enzyme productivity from kitchen waste was over two-fold higher than that from wheat bran with additional nutrients. Without any recovery treatment, the produced glucoamylase could be used directly to hydrolyse sKW slurry. The optimum enzyme dose 8% (crude enzyme/kichen waste, w/w) was not too big, and was sufficient to hydrolyse 10% (dry basis) sKW slurry to produce a maximum amount of reducing sugar of 55.4 g L-1.Kitchen waste from dining rooms accounts for a considerable proportion of municipal solid garbage, and economical recycle ways are needed to be developed. This study investigated glucoamylase production from kitchen waste and the feasibility of kitchen waste hydrolysis by the crude enzymes produced. The key problems of high water content and poor porosity in kitchen waste for glucoamylase production under solid-state fermentation could be solved readily by the addition of corn stover or paddy husk. As a support medium, corn stover was better than paddy husk. Smashed kitchen waste (sKW) mixed with corn stover in the ratio of 3.75 : 1 (dry basis) produced 1838 U g(-1) of glucoamylase by Aspergillus niger UV-60 within 96 h. The enzyme productivity from kitchen waste was over two-fold higher than that from wheat bran with additional nutrients. Without any recovery treatment, the produced glucoamylase could be used directly to hydrolyse sKW slurry. The optimum enzyme dose 8% (crude enzyme/kichen waste, w/w) was not too big, and was sufficient to hydrolyse 10% (dry basis) sKW slurry to produce a maximum amount of reducing sugar of 55.4 g L(-1).

Research on Immobilization Carrier on Ethanol Fermentation from Food Waste

Resource technology for food waste has become the research hot recently. To perform ethanol fermentation from food waste could realize energy recovery and pollution prevention. This study investigated the effects of two kinds of immobilization carriers, loofa sponge and fiber ball on ethanol fermentation from food waste. The seven runs of fermentation experiments demonstrated that the fermentation broth with fiber ball showed an increase of residue sugar concentration (31.98g/l) and a decrease of sugar utilization ratio (60.02%) in the fourth run. When it came to the seventh run of experiment, the sugar utilization ratio was only 49.04%, which showed that the fermentation yield by the yeast decreased significantly. While the fermentation by loofa sponge revealed stable fermentation efficiency, the sugar utilization ratio were all above 80%. The effect of size and inoculum for loofa sponge showed that 3 gram dry loofa sponge in 100 ml saccharification liquid was suitable. While the size had little effect on the fermentation.

Discharge and Disposal of Coking Residue and Distribution Characteristics of PAHs in it

The research studied the treatment ways of discharging coking residues and the distribution characteristics of PAHs in two kinds of typical coking residues. The outputs of coal tar (100,000t/a for Plant A, 84,000t/a for Plant B) were great and it had become an important by-product. Coal tar residue, with the yields of 4,500 t/a and 6,400 t/a for Plant A and B, respectively, were always reused for coal blending. The concentration of PAHs with 5-6 aromatic rings was 1.08×104 mg/kg in coal tar residue, the concentration of PAHs in coke discharging smoke & dust (28.81 mg/kg) was relatively low compared with coal tar residue. The ∑BaPeq were 4.2×103 mg/kg and 0.71 mg/kg for coal tar residue and coke discharging smoke & dust, respectively.

Optimization of Lactic Acid Production from Food Waste by the Saccharification of Bacillus subtili

In order to reduce the costs of production and increase the lactic acid yields, this research adopts Bacillus subtilis to substitute enzymes. The method used in the study is two-phase fermentation - inoculate Bacillus subtilis to food waste to produce sugar, and then inoculate Lactobacillus to food waste to yield lactic acid. 87.22 g l–1 of total sugar can be obtained from non-autoclaved food waste in 30 h of saccharification at 40 centigrade. After two-phase fermentation, the optimal lactic acid concentration was 50.77g/L. The results indicate that two-phase fermentation is better than synchronous saccharification fermentation.

A Remediation Study of Soils Contaminated by Chlorinated Hydrocarbons with Mechanical Soil Aeration

Mechanical soil aeration is an effective and low cost ex-situ remediation technique suitable for large areas of volatile organic contaminated sites. To understand the effectiveness of the remediation technique, the current study remediated an abandoned industry site for a typical chlor-alkali chemical using this technology. The results showed that the technology is effective in the remediation of volatile organic compounds with a pass percentage greater than 90%. The results also showed that a lower vapor pressure or higher molecular weight with the similar concentration of pollution resulted in higher residual concentrations, which need increasing agitation frequency or machine power to promote the volatilization of pollutants. In addition, we found that the more pollution or water or organic matters (more than 1%) contained, the higher concentration of residual. These type of soils should be remediated not only by physical agitations but also by other strengthen measures and long period. The present study aims to promote the remediation of contaminated sites, especially large areas contaminated by volatile contaminants.

Discharge and Disposal of Coal Gasification Methanol Production Residue and Distribution Characteristics of PAHs in it

To determine the quantities and the treatment ways of coal gasification methanol production residues, questionnaire survey and field investigation were carried out in this research. Moreover, the distribution characteristics of PAHs in two typical residues were determined by GC-MS technique, according to USEPA8100 method. The outputs of gasifier slag and boiler ash for were 127,494 t/a and 164,850t/a, respectively, all the boiler ash and 80% of the gasifier slag would be reused for brick-making. Coal tar residue, with the yield of 480 t/a, was always delivered to coke plant for coking, which was a effective measure to save energy and solve the environmental issues caused by the storage of this residue. The results indicated that the concentration of PAHs with 5-6 aromatic rings was 905 mg/kg in coal tar residue, accounting for 9.23% of the total PAHs concentration, its Benzo (a) pyrene concentration was 160 mg/kg, making it a major health hazard. The concentration of PAHs in gasifier slag was 189mg/kg and the PAHs with 2-3 aromatic rings accounted as high as 81.41% of the total PAHs concentration, the PAHs with 5-6 aromatic rings made up only 1.1%. TheBaPeq were 322.9 mg/kg and 0.23 mg/kg for coal tar residue and gasifier slag, respectively.

Pollution Characteristic Analysis during the Recycling Process of Waste Methanol

According to the directory of hazardous waste, Waste methanol belongs to the hazardous waste. Production of methanol will produce ethers, ketones and other impurities. During the distillation for waste methanol, high concentrations of distillation waste will be produced. In this paper, waste methanol recovery process in a southern chemical plant was adopted as the research object. Methanol and distillation waste were sampled and analyzed, combined with domestic research findings about waste methanol and other organic pollutants, the emission and pollution characteristics of waste methanol were discussed. The results show that Ethers and ketones are the main contaminants of methanol; it has potential hazards for products with such methanol as raw materials. The distillation waste has high COD concentration, containes methanol, mixed alcohol and other toxic substances, which has the risks for environmental pollution and human health.

The Influence of Organic Loading Rates on Hydrolysis and Acidification Rates of Fruit and Vegetable Waste Anaerobic Fermentation

Continuous flow anaerobic fermentation experiments of fruit and vegetable waste were carried out in four laboratory-scale anaerobic acidification reactors with pH controlling system. The organic loading rate (OLR) were 13, 20, 30 kg COD/m3 d gradually and a hydraulic retention time (HRT) of 3 days were constantly. The results, obtained from the three stages operation, showed that hydrolysis rate increased along with the rising of OLR, to the highest of 79.3%, and acidification rate decreased on the contrary, showing that the activity of acidification bacteria was inhibited by high OLR. High pH value contributed to the process of hydrolysis and acidification especially under high OLR in the acidogenic phase of the fruit and vegetable waste.

Effect on Ultrafiltration of Lactic Acid Fermentation Broth by Using Inclined Tubes Sedimentation as Pretreatment

lactic acid, inclined tube sedimentation, ultrafiltration, flow velocity Abstract This study combined inclined tube sedimentation with ultrafiltration to remove the particles and protein in lactic acid fermentation broth. The influence of flow velocity on the extract property was investigated as well as the variations of flux, protein removal rate and lactic acid recovery in ultrafiltration. The result indicated that the inclined tube sedimentation was effective to remove the particles of fermentation broth. When the flow velocity was 0.031cm/s, the percentage of particles smaller than 10μm was 77%. The flow velocity 0.143cm/s in inclined tube sedimentation was more suitable in this study. SS removal rate can achieve 45.5% while protein removal rate and lactic acid recovery can be maintained above 90% in such situation

Separations of Ammonium Lactate from Lactic Salts by Electrodialysis

This study is focus on the separations of ammonium lactate from lactic salts by Electrodialysis. Effects of work voltage, ammonium lactate initial concentration in the demineralization chamber on ammonium lactate separation in an electrodialyzer with heterogeneous membranes have been studied during the process of electrodialysis. Experimental results show that the optimum conditions of the process of ammonium lactate concentration by electrodialysis are the following: 18V work voltage, 40g/L ammonium lactate initial concentration.