Advanced Materials Research Vols. 955-959

Abstract: Aiming at the difficulty of treating dyeing wastewater, the limitation of the traditional electrolysis method, the high cost of active carbon and the environmental pollution of the chicken manure in farms, the paper put forward a new method of using iron combined with biological carbon derived from chicken manure forming internal electrolysis to treat dyeing wastewater. It discussed the effects of mass ratio of iron and biological carbon derived from chicken manure, pH, reaction time, the particle size of iron filings, the aeration rate, circulation velocity and the circling liquid volume on the removal rate of the organic matter in wastewater. The result showed that iron combined with biological carbon derived from chicken manure forming internal electrolysis to treat dyeing wastewater could "using waste to treat waste" and the effect was better. The removal rate of COD was over 85% and the decolorization rate was over 95% when the mass ratio of iron and biological carbon derived from chicken manure was 1:1, the PH was 6, reaction time was was 60min, the particle size of iron filings was 0.9~2.0mm, the aeration rate was 10mL/min, circulation velocity was 50r/min and the circling liquid volume was 2000mL.

Abstract: Activated carbon of activated sludge and straw with pyrolysis was used as adsorbent, and its adsorption of organic matter in the leachate and influence facts were studied. The results showed that the economic and reasonable addition of straw in the raw of activated sludge was 45% and the optimum adsorption conditions were 40 min, duration of pH 4.0 and resin dosage 2%,the removal rate of COD reach 69.63%. Langmuir isotherm equation could better describe the adsorption behavior of COD on the activated carbon and it was a monolayer adsorption reaction.

Abstract: In this paper, activated sludge process enhanced by ultrasound was applied to treat the chemical production wastewater containing nitroaromatic compound after ultrasonic pretreatment. The factors influence to treatment effect such as ultrasound power and frequency, irradiation time were investigated by experiment. The mechanism of ultrasound enhanced activated sludge process was analyzed. The experimental results show that ultrasonic irradiation with appropriate parameters can effectively enhance sludge activity, improve the treatment efficiency. The optimal treatment conditions are as follows: ultrasound power 10W, frequency 25kHz, irradiation time 15min.

Abstract: Removal of SO₂ and NO from the flue gas using an aqueous sodium chlorite solution was achieved in a bubbling reactor, ORP and pH were used as monitoring parameter. The effect of pH, NaClO₂ feeding rate and SO₂ concentration on simultaneous removal of SO₂ and NO_x efficiencies were systematical investigated. The results showed that SO₂ removal efficiency was always 100% and NO_x removal efficiency could achieve 65% at optimized conditions, the optimized pH value of 5-5.5 was observed. The correlation analysis among ORP, original pH, NaClO₂ feeding rate and input SO₂ concentration was established using multiple regression equations.

Abstract: A novel non-aeration membrane bioreactor (N-MBR) is exploited based on the combination of bio-film process and membrane filtration process, of which the ceramic membrane module is made by the material of Al₂O₃. The relationship of the membrane diameter, the membrane flux, trans-membrane pressure (TMP) and the side stream velocity is investigated, as well as the treatment effect for domestic wastewater. The result shows that the N-MBR set-up with the membrane pore size of 1.5μm was adopted to treat the domestic wastewater under the condition of TMP 0.008MPa, side stream velocity 8m/min for continuous working 30 days. The effluent COD average concentration is less than 21mg/L and NH₃-N concentration is less than 1mg/L all the time. The removal efficiency of COD and NH₃-N is 85 percent and 98 percent respectively. The average energy consumption is 2.90± 0.55 kWh/m³ (permeate), which is reduced 50 percent than that of conventional membrane bioreactor.

Abstract: This paper used the ion exchange resin method to treat the heavy metal ion Cu²⁺ of a chemical wastewater and studied the flow velocity, pH and the temperature’s effect on Cu²⁺ removal effect by macroporous strongly acidic styrene type cation exchange resin D001. The results shown that: when the flow velocity was 1.5 mL/min, pH was 6.0 and the temperature was 30°C, the removal rate of Cu²⁺ by D001 reached 99.8%. The chemical wastewater could achieve the wastewater’s discharge standard.

Abstract: Coking wastewater contains high concentration of refractory and toxic compounds. The effluent quality usually cannot meet the discharge limits after single conventional biological treatment processes. In order to find more effective coking wastewater treatment process, a serious hybrid treatment process were reviewed in this paper, which include: anoxic-anaerobic-oxic(A2/O) combined with membrane bioreactor (MBR); Fe/C micro electrolysis combined with Fenton process. Fenton oxidation combined with biologically process. Wastewater quality and operating parameters were compared. Through this review, we found that hybrid process is more efficiency to treat coking wastewater.

Abstract: Polychlorinated biphenyls, which are toxic, carcinogenic and mutagenic, are ubiquitous and persistent in environment. For PCBs are hydrophobic and lipophilic, soils or sediments are their final destinations in environment. Consequently, PCBs-contaminated soils or sediments are increasingly attracting more and more attention. In this paper, basic properties of PCBs and the situation of PCBs-contaminated soils or sediments were described. Remediation technologies of PCBs-contaminated soils or sediments inside and outside China were reviewed. This paper also presented the prospect of technology development.

Abstract: Wheat straws were pyrolyzed at two temperatures (200 and 400°C). For two biochar, the Scanning electron microscope (SEM) and the BET surface area were analyzed. The thermodynamics of sodium pentachlorophenate adsorption on biochar were examined. Adsorption isotherm of sodium pentachlorophenate on biochar was determined and correlated with two well-known isotherm equations (Langmuir and Freundlich adsorption isotherm equation). The equilibrium data for sodium pentachlorophenate adsorption were fitted well with the Freundlich adsorption model. The thermodynamic parameters of Gibbs free energy (△G^θ), enthalpy (△H^θ), and entropy (△S^θ) were also calculated, and the positive value of △H^θ suggests the endothermic nature of the adsorption, whereas the negative values of △G^θ tend (s) to prove the spontaneous nature of the adsorption process.

Abstract: Soil pollution around railroad sites is mainly caused by heavy oils such as diesel and lubricants. In particular, the majority of contamination in soil around railroad turnouts is caused by oil that drips off of railcars and lubricants that leak during vehicle maintenance. Generally, removing lubricants from contaminated soil is more difficult than removing diesel, due to the properties of the respective oils. This study aims to investigate alternative remediation method of lubricant-contaminated soils around railroad turnouts. The EK-Fenton process was used to clean up the lubricant-contaminated railroad soil. Several operating conditions were tested, including the concentration of hydrogen peroxide, and electrolyte types and concentrations. We determined that the removal efficiency was affected by the amount of EOF in the soil and its oxidizing capacity. The TPH removal efficiency was greatest at 0.1 M of NaCl electrolyte and 5 % (v/v) of hydrogen peroxide. This shows that the in-situ EK-Fenton process is a promising remediation technique for decontaminating railroad soil polluted with lubricant oil.