Advanced Materials Research Vols. 518-523

Abstract: The landfill leachate is a kind of complicated waste water which is hard to be treated at present. In this paper seven dominant stains that can effectively degrade COD in leachate were isolated by increasing the concentration of leachate. The influence of treated time, temperature, pH on treatment efficiency of leachate with these dominant stains were studied. The results showed that five bacterial strains, one Actinomyces strain and one mould strain possess fairly high rate to eliminate COD in leachate. The optimum time of degradation of COD in leachate was 3 days, and the pH was suitable for strains which the best was 7. In a broad temperature range from 25°C to 35°C, the COD in leachate could be effectively degraded by all of seven strains.

Abstract: The excess activated sludge from the Shanghai Qingpu sewage treatment plant was hydrolyzed by papain hydrolysis to extract protein. The results showed that the conditions of optimal papain hydrolysis process are described as follows: enzyme/substrate 6%, pH 6.5, the ratio of liquid to solid 4:1, hydrolysis time 5.5h and hydrolysis temperature 55 °C. On this basis, the contents of heavy metals and some kinds of amino acid from the extracts, while security and nutrition were taken into consideration, were determined. The results showed that the contents of heavy metals were lower, living up to the Health Standard for Animal Feed (China), and some kinds of amino acid were essential for animal growth in the extracts. So it was possible to take the extracts as animal feed additives.

Abstract: Fate of mercury (Hg) in a modern sanitary municipal solid waste (MSW) landfill in Guiyang, China was investigated to assess the potential lost of Hg to ambient environment through different pathways. Mercury content in MSW, leachate, and mercury airborne emission rate through the surface and the vent pipe system were determined. A mass balance calculation showed that, roughly 0.67% of Hg entered into the landfill each year was lost into the surrounding environment, which was dominated by the pathway of working face (98.47%), then soil covers (1.28%), leachate (0.22%) and landfill gas vent pipes (0.03%).

Abstract: Large amount of dredged sediments has caused a series of social and environmental problems, because of serious heavy metal contamination. A novel method is reported here to recycle the dredged sediments in an eco-friendly manner by combining solidification/stabilization (S/S) treatment and vegetation. In this work, we formulated Portland cement, bontonite and quicklime with fly ash to solidify/stabilize the sediment dredged from a polluted river in Guangzhou, China. The stabilization effect was evaluated, and the influences of S/S products on plant growth were also investigated. The results indicate that S/S products have stable fixing capacities for Cd, Pb, and Ni in the dredged sediment. The results of subsequent plant growth experiment suggest that S/S products could be used as a media to grow plants, and fertilizer to sustain the growth of the plants. Vetiver growing in S/S products would stress on the plants and enhance the expression of enzymes, thus increasing the tolerance of the plants to the stress. Our research on combining S/S product and vegetation has demonstrated that it is feasible to recycle the dredged sediment eco-friendly. S/S product combined with vetiver grass has great potential in ecological restoration.

Abstract: Lignite char, abandoned in Northwest China, was utilized as raw material precursor to produce hydrogen sulfide absorbent by surface modification with different methods. The absorbent was suitable for the removal of small amount of H2S in feed gas and exhibited high efficiency and recycle ability. After the modification, the physicochemical properties of lignite char were improved significantly, such as surface area, texture structure and functional groups contents and so on. The evaluation results indicated that the desulfurization performance could be increased obviously in H2S removal process after the modification. Moreover, it was an effectual way to enhance the desulfurization ability of the absorbents by loading some metal oxides, despite that could change the reaction path and was harmful to the absorbents’ regeneration.

Abstract: To elevate the air flow rate in vent pipes of semi-aerobic landfill, promote oxygen transmit into waste and methane mitigation, a wind-driven cowl was fixed on one of the two semi-aerobic landfills’ vent pipe. With the aim of figuring out the influence of cowl on the spatial distribution of oxygen under different climates, wind speeds were set at 3 m/s, 5 m/s, 7 m/s and 0 m/s sequentially. Oxygen concentrations and temperatures were recorded once a week. Data from experimental results indicated that oxygen concentrations went up along with the height above the bottom of landfill after deducting the oxygen transported by leachate collection pipes. Average oxygen concentrations except the surface layer were 3.5%, 4.2%, 3.8%, 3.0% for S-A with cowl and 2.9%, 3.4%, 3.7%, 3.0% for S-A under the wind speeds of 3 m/s, 5 m/s, 7 m/s, 0 m/s, respectively. Meantime, the aerobic radius in S-A with cowl were 0.84 m, 1.01 m, 0.87 m, 0.62 m and 0.76 m, 0.84 m, 0.87 m, 0.65 m in S-A. The effect of the cowl on oxygen transmission maximized at the wind speed of 5 m/s. It is clearly that wind energy can be better used on enhancing the ventilation in vent pipe and expanding aerobic radius after application of cowl.

Abstract: In upstream petroleum industry, one of the major operations that can potentially impact the environment is drilling. A major component of the wastes generated during drilling are the rock cuttings and the drilling fluids. The drilling fluids can have different chemical composition and various additives. Spilled or improperly disposed drilling wastes have the potential to harm plants and animals, and it should be managed to minimize risk to human health and the environment. The increasing environmental legislation surrounding drilling operations has led to a rapid rise in drilling waste management spending by operators. Managing wastes to minimize their harm potential to health and environment is the international concern and requires efficient management of wastes to reduce the environmental impacts. The management and control of waste which develops from the strategy can also have the beneficial effect of reducing the number of health related issues.This paper presents the waste management including recognizing the waste sources and methods which are used to minimize the impaction to environment and human health from drilling waste. This paper also reviews the strategy of drilling waste management which could reduce the number of health related issues as well as environment pollution.

Abstract: Stirred ball mill(SBM) method is one of the usually method which applied in large scale application cases of sludge disintegration. This study focuses on investigation the mechanism of sludge disintegration by SBM method. Besides analysis general indicators of SCOD, TN, TP and calculated the disintegration rate of COD (DDCOD). The result indicated the SCOD and DDCOD increased with the disintegration time. As DDCOD increased to the highest of 18.6% at the treated time of 60min, it shown that SBM was not more efficient in disintegration of biomass into so smaller particle that easily dissolved in water.

Abstract: Polyester/wool blended fabrics were studied in this paper, and two methods were developed to separate polyester and wool fiber from physical and chemical respectively according to the characteristic differences between them. The characteristics and the ranges each method can be applied to were pointed out after analyzing factors like cost and conditions of production, complexity of the equipments, the length and continuity of the process and also the recovery of the product and pollutions. The study of this work not only decreased the waste of polyester/wool blended fabrics but also made full use of the two fibers. Also, the secondary pollution of polyester fiber was reduced and the value of wool can be reflected.

Abstract: Pyrolytic conversion of sewage sludge to biochar, oil and gas is an environmentally and economically acceptable way comparable to conventional options for sewage sludge disposal. The aim of this paper is to investigate the influence of pyrolysis temperature on production of biochar fraction for agronomic application, oil and gas fractions for energy utilization. Sewage sludge samples collected from an urban sewage treatment plant were pyrolysed in a bench–scale quartz tubular furnace over the temperature range of 300-700°C.The results indicated that the biochar fraction yield decreased, the yields of liquid (oil and water) fraction and gas fraction increased by evaluating the pyrolysis temperature. Concentration of heavy metals and nutrient elements present in biochar varied with pyrolysis temperature, the heating value of oil from liquid fraction fluctuated between 26938.3 and 30757.9kJ/kg, the heating value of gas fraction increased from 4012kJ/Nm3 to 12077 kJ/Nm3 with the increasing pyrolysis temperature.