Advanced Materials Research Vols. 1073-1076

Abstract: Aiming at the problem of the traditional flue gas desulfurization and effluent disposal, two identical dual-chambered Microbial fuel cells (MFCs) are designed to remove man-made flue gas pre-treatment wastewater (FGPW). Glucose is used as the carbon source of the Sulfate reducing bacteria (SRB). Carbon cloth is used as the material of anodic and cathode. The treatment performance of flue gas pre-treatment wastewater and the possibility of electricity harvesting and sulfur recovery were investigated. The results show that the output voltage is 0.68-0.72V and the maximum current density is 28.12mA/m2 at pH=7.520. The concentration of sulfate measured with ion chromatography is decreased gradually during the operation of MFC. The elemental sulfur is found in carbon cloth (taken from the MFC after working for 58 days) by analysis with XPS. The results suggest that treatment of flue gas pre-treatment wastewater and electricity harvesting and sulfur recovery by MFC is technical feasibility.

Abstract: Using novel dual cathode/electro/Fe²⁺/S₂O₈^2- system to treat pickle sauerkraut wastewater, the paper investigates the influencing factors (S₂O₈^2- dosage, Fe^{2 +} dosage, current density, Wastewater pH, electrode plate distance) of the organic matters removal and the treatment effect. Test results show that the degree of various factors influence on COD removal of sauerkraut wastewater is different. The COD removal is little effected by pH, while largely effected by current density, dosage of Fe^{2 +} and S₂O₈^2- dosage. Under the optimum experiment conditions, current density for 30mA/cm^-2, dosage of Fe^{2 +} for 8mmol/L, S₂O₈^2- dosage for 12 mmol/L, electrode plate distance for 2 cm and pH=6, sixty minutes electrolysis, wastewater removal rate reach up to 92.6%. These results suggest that this electrochemical oxidation process by dual cathode/electro-Fe²⁺-S₂O₈^2- system might provide an alternative for the degradation of pickle sauerkraut wastewater.

Abstract: Aiming at power plants denitrification system existing chimney entrance NOx concentration than denitrification system outlet NOx concentration of "upside down" phenomenon, adjust and optimize the test denitrification system, denitrification system NOx concentration distribution uniformity can be obviously improved after the adjustment, improve economy of denitration system operation. At the same time, the denitrification system operation suggestion.

Abstract: Oily sludge is inevitably produced in numerous petroleum processing operations. Five oily sludge samples were collected to identify the compositions and to characterize the extracted solids. The results indicated that three fifths of the samples contained significant amounts of oil and could be potentially recovered as energy resources. All of the samples had high concentration of water. The compositions of C, H, and N, as well as H/C in the separated oils were close to those in oil sands bitumen. The high concentration of asphaltenes agreed with the low H/C. The XRD spectra showed that the major minerals contained in the extracted solids were quartz and calcite.

Abstract: Potassium ferrate was used to enhance sludge dewatering and the mechanism was studied. Sludge floc structure was effectively destroyed by potassium ferrate, and the soluble COD, proteins and polysaccharides increased with the increase of potassium ferrate. The optimal dose for sludge disintegration was 100 mg/gSS, and the corresponding maximal SCOD, soluble proteins and polysaccharides concentrations were 2455, 800 and 145 mg/L, respectively. Sludge dewaterability was enhanced significantly with cationic polyacrylamide (C-PAM) application, and the SRF decreased to 0.72×10¹⁰ m/kg from 50.12×10¹⁰ m/kg. This study indicated that the potassium ferrate pretreatment was helpful for enhancing sludge dewaterability and reducing the coagulant dose.

Abstract: The research in this paper focuses on improving the COD removal rate of the coking wastewater and the NH3-N removal rate and thus diversifying measures to dispose microbial floras in wastewater from the coal chemical industry. The means of adding nutrients, acid treatment and coagulation sedimentation react synergistically to dispose the organic contaminants in the coking wastewater. We attempted to combine Saccharomyces cerevisiae, Torula yeast, tropical Candida mycoderma, etc. to exploit the respective advantages to the full and improve the disposal effect. According to the COD sample (27000-30000) and NH3-N (2500-3000) offered by the client company, the COD removal rate ranged from 24.2% to 31.8% in the mixed experiment group of Saccharomyces cerevisiae and Torula yeast, with NH3-N removal rate from 63.5% to 69.6%. Obviously, the NH3-N removal rate produced good effect. Meanwhile, the COD removal rate ranged form 35.3% to 41.8% in the experiment group only adjusting PH value and the NH3-N removal rate ranged from 40.2% to 50.2%. It is obvious that NH3-N removal rate is influenced by the amount of bacterial strain.

Abstract: Produced in industrial production processes such as electrolysis, electroplate and metal pickling, industrial wastewater, which contains acids, varieties of heavy metal and whose pH value is less than 6, can be very damaging to our daily life and environment and is an urgent issue to be solved. In recent years, with environmental protection becoming an important issue around the world, and environmental regulations becoming more and more complete, the traditional water treatment technology which can cause secondary pollution is gradually restricted, and this leads to the result that environmental scientists and engineers pay more attention on the development and application of "environmentally friendly" water treatment technology ^[1]. Of all acid wastewater neutralizers, magnesium hydroxide, known as "green and safe neutralizer" ^{[2, 3]}, is safe, reliable, non-toxic, harmless, and has high buffer performance, high activity, high adsorption capacity, and no corrosivity compared with traditional strong alkali substances (such as CaO, Ca (OH) ₂ and NaOH, etc.). Therefore magnesium hydroxide has been widely used in the acid wastewater neutralization ^[4].

Abstract: Lignite activated carbon was provided through lignite which is treated specially. The adsorption capacity and mechanism of COD from Coal gasification wastewater by lignite activated carbon have been studied.The adsorption capacities of lignite activated carbon at different times were obtained by concentration of COD in the remainder solution. Three simplified kinetic models: pseudo-first-order, pseudo-second-order, intraparticle diffusion equations were adopted to examine the mechanism of the adsorption process. The results showed that the adsorption can be expressed by the pseudo-second-order model. The adsorption balance capacity was obtained as 50.8mg·g^-1 (298K), and the adsorption balance capacity decreased with increasing of temperature, which showed that the adsorption process was exothermic. The adsorption activation energy (Ea) was calculated as 5.76kJ·mol^-1, and it showed that the adsorption process was Physical adsorption. This study explored new treatment channels for lignite comprehensive utilization..

Abstract: The aged crumb rubber modified asphalt (abbreviated as CRMA) was recycled with two methods which were adding fresh CRMA binder and adding recycling agent to investigate the recycling feasibility of aged CRMA binder. The performance of recycled CRMA binder was evaluated systematically with a variety of indices, including penetration, softening point, ductility and viscosity. The results indicate that the performance of recycled CRMA binder has good correlation with the content of the fresh CRMA binder or recycling agent. The performance of recycled CRMA binder mixing with the fresh CRMA binder or recycling agent with the optimistic content is improved and can meet the technical requirements. According to the relevant technical standards in “Guidelines for design and construction of asphalt rubber and mixtures in Beijing”, the index of recycled CRMA binder can reach the standard when the content of fresh CRMA binder is 70% or content of recycling agent is 6%. The experimental results show that the recycling of the aged CRMA asphalt is feasible.

Abstract: In this study, the performance treatment of horizontal subsurface flow constructed wetland (HSFCW) was evaluated. The HSFCW built as a tertiary treatment process after the biological reactors to improve the effluent quality. The HSFCW system was operated with different hydraulic loading rates (HLRs) ranged from 0.15 to 0.333 m³/ (m².d) to assess their influence on removal efficiency. During the system operation time, the average temperature was ranged of 22.3 to 31.2 °C and pH ranges was 7.3 – 8.1. The Ipomoea aquatica (Chinese spinach) planted into HSFCW system and the growth parameters during the experimental operation observed. The Ipomoea aquatica growth parameters such as the plant height, a fresh and dry weights were monitored and measured. The influent and effluent of chemical oxygen demand (COD), ammonium nitrogen (NH₄-N), total nitrogen (TN) and total phosphorus (TP) were examined. The removal efficiency for all parameters showed decreased with an increase in HLR from 0.15 to 0.333 m³/ (m².day). The results demonstrated that the average removal efficiency of the COD, NH₄-N, TN and TP during system operation is 52.9%, 64.6%, 58.2% and 72.8% respectively. These results confirm that the HSFCW has a good efficient in treatment and can be used for the nutrients and organic matter removal from the domestic wastewater.