Advanced Materials Research Vols. 610-613

Abstract: According to the characteristics of oily wastewater, microwave technology was introduced to separate aviation kerosene from oily water. The uniform design with mixed level including main influence factors was applied to design the experimental scheme. The influence factors such as oil content, radiation power, radiation time length and standing time after radiation were considered. The influence of these factors on separation of oil from oily water was investigated through experiments, and deoiling amount formula was regressed. The results show that these four factors are positive to the separation of oily wastewater, of which oil content is the most important to the separation, the product of radiation power and radiation time is the second, and standing time is the third. Treatment of oily wastewater using microwave benefits to the efficiency of discharging sewage and the recovery of oil product to meet the relative standards.

Abstract: The imperfect recycling price system becomes the main obstacle that blocks the development of China’s ‘Urban Mineral’ industry. It is very necessary to raise and diverse the current recycling prices in order to raise the customer’s enthusiasm. A risk-based model for designing the grading recycling price was proposed in this work. For better comparison, the model for designing unified recycling price was also constructed. The simulation results show that although the grading recycling price level is higher than the unified price, more profits and quantities could be generated by the grading recycling price system. This proves that the grading recycling price system is superior to the unified price system in encouraging the customer to provide more waste ‘Urban Mineral’ Resources.

Abstract: The brine from vinylidene chloride (VDC) synthesis contains high concentration of sodium chloride and halogenated hydrocarbons which are all volatile organic chemicals (VOCs). Based on the contaminations’ characteristics in the brine, an air-stripping process was firstly applied for removing most of the halogenated hydrocarbons in the brine, and then the H₂O₂/UV oxidation process was used for polishing treatment so that the treated brine could be reused as a raw material for a chloro-alkali process. The results showed the residual TOC after air-stripping could be effectively removed by H₂O₂/UV process, and the TOC level of the brine from VDC production could be decreased to less than 10 mg/L through combined air-stripping and H₂O₂/UV oxidation process, and than the treated brine could be reused as raw material for a chloro-alkali process.

Abstract: the influence rules for the settlement of tailings from bauxite direct flotation were investigated under the different pulp pH and dosage of inorganic flocculants(such as Al2(OH)nCl6-n, Al2(SO4)3) and organic flocculants(nonionic polyacrylamide(080), cationic polyacrylamide(603), anionic polyacrylamide(JB-TR782)). The results show that surface static potential of particles is the key effect factor for the settlement of tailings. The good settlement of tailings can be obtained with adding a little dosage of flocculants when pH was kept at about 7.0, 080 and 603 can increase the sedimentation rate in the alkaline pulp evidently, the organic flocculants can do as well. The combination of Al2(SO4)3 and 080 could produce good sedimentation results for tailings and the dosage of Al2(SO4)3 and 080 can be decreased as well, so it has an application prospect.

Abstract: The passenger transport amount is increasing quickly in China in recent years. It was 15.9, 17.9, 18.8 and 19.8 billion person-times in 2003, 2004, 2005 and 2006, respectively. One billion person-times were increased yearly. But treatments of passenger transport excrement have become a more and more difficult problem. According to calculation passenger transport feces was 19.8 million tons and the urine was 59.5 million tons in 2006. If the excrement is discharged directly along the way, the environment must be polluted seriously, the pestilences will be propagated and it will be a colossal waste of resources. In this paper, excretory manners and the components of feces and urine were studied and the treatment manners of the passenger transport excrement at home and abroad were compared. A new treatment method of the passenger transport excrement was put forward that the feces and urine were collected separately in passenger transport, then the collected feces and urine were uninstalled at the station, the urine was used openly to fertilize soil and feces was done anaerobic digestion to get the biogas as fuel. Residue after feces digested was made into fertilizer to fertilize soil. The more economic and environmental benefit can be obtained by using this treatment manner. And a fresh excrement collector was designed.

Abstract: As the electrochemical oxidation technology is an effective and reliable clean technology, in this study the electrochemical oxidation activated sludge process was developed, in which the electrolysis reactor with homocentric circle arrangement electrode was installed, with Ti/RuO2 being used as reticular plates. The results showed that the electrochemical oxidation can reduce activated sludge production substantially. The lysis efficiency of activated sludge achieved was 29.98% in the experiment under the optimal oxidation conditions as follows: pH=12, 60 min of intermittent electrolysis time, working voltage of 6 V and initial VSS concentration of 4670 mg·L-1,while the SCOD and TP being released from cell lysis at the maximum of 712.2 and 33 mg·L-1 respectively; and the NH3-N also reached the maximum and presented a declining trend with operation time, which showed that this conditions were the best for electrolysis oxidation of activated sludge.

Abstract: Four types of reverse osmosis membranes (LP, ULP, XLP and FR) were used for the treatment and reuse of the pharmaceutical condensates. The desalination rate and removal of TOC with pH 6.8 is significantly higher than pH 3.2 for all of the four membranes. When the pH is 6.8 the FR reverse osmosis membrane has the highest desalination rate, removal of TOC, permeate flux and the lowest transmembrane pressure, and it is energy conservation and not easy to be contaminated. So the FR reverse osmosis membrane is Suitable for the treatment of pharmaceutical condensate.

Abstract: Electrochemical dissolution method was used to achieve the recycling of waste hard alloy. Tungsten, cobalt powder and cobalt salts can be obtained through the control of suitable conditions of electric dissolution process ,such as cleaning of waste hard alloy, electric dissolution of waste hard alloy, knocking the basket, treatment of cobalt chloride etc. Tungsten and cobalt chloride solution can be obtained directly by this method, and thus to obtain the cobalt powder and cobalt salts. Recovery rate of WC and cobalt were above 98% and 92-95%.

Abstract: Fast consumption of high quality phosphorus mines and uneven distribution in the world result in the shortage crisis for phosphorus, meanwhile lots of phosphate compounds which are discharged into nature water bodies by human beings have already induced many environmental problems. Because of this situation, phosphorus recovery from sewage sludge working in the aeration tank of wastewater treatment plant (WWTP) has been researched in the present study. Poly-phosphate (poly-P) and total phosphate (T-P) accumulated inside activated sludge could be released by thermal treatment at low temperature, 30% poly-P and 29% T-P could be released from sludge by heating at 70°C. Different kinds of pretreatments had been tested to improve phosphorus release from activated sludge in thermal treatment; addition of chelating reagent at final concentration of 2 mM before thermal treatment could improve the phosphorus release obviously, 68% poly-P and 53% T-P could be released into liquid phase. Approximately 85% T-P could be precipitated with calcium at pH 11; it was interesting to find precipitation occurred in neutral condition without pH adjustment.

Abstract: This research shows the progress of geopolymer synthesis based on high calcium fly ash. In this study, the fly ash contents of 60, 65, and 70 percents by weight and sodium hydroxide solution concentrations of 8 to 12 M were used. Alkali activators for the geopolymer synthesis consisted of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) and the weight ratio of Na2SiO3 to NaOH were 0.50, 1.00, and 1.50. Drying shrinkage deformation of geopolymer paste was investigated by longitudinal measurement in a room temperature. Generally, the drying shrinkage behavior could be divided into three groups. The minimum drying shrinkage strain below 3,000 x 10-6 mm/mm was observed. The results indicated that an increase in the fly ash to alkali solution ratio and the decease of NaOH concentration significantly decreased the drying shrinkage strain. The optimum ratio of Na2SiO3 to NaOH was 1.0. The findings show that high calcium fly ash geopolymer binder could be used for alternative construction materials with low shrinkage strain.