Advanced Materials Research Vol. 878

Abstract: The text principal introduced sludge drying& incineration integration circular process kiln equipment and technology principle. By utilized sludgy heat of oneself incineration quantity & pass supplement thermal way & the cycle of complex process, it realized sludge drying incineration circular process. The quantity of dust of smoke poisonous and noxious substance was valid reduced. Not only probability of secondary pollution of smoke and realized reached the standard discharge of exhaust gas. It provided a new drying incineration technology and method and principle for disposition sludge. It realized reduction and harmless and stabilization resource utilization of sludge.

Abstract: Three kinds of surplus activated sludge were pretreated by alkali and combination of alkali and ultrasonic. The changes of PO₄³-P, TP, SCOD, TOC, TS, VS before and after pretreatment were investigated. The results showed that phosphorus and organic matter could be released into supernatant both by alkali and ultrasonic. The surplus activated sludge from municipal wastewater treatment plant was easier to be broken than that from pharmaceutical wastewater treatment plant. The activated sludge from Qinghe wastewater treatment plant could be selected for further phosphorus recovery since the largest quantity of phosphorus release and the lowest organic matter release ratio among the three kinds of surplus activated sludge.

Abstract: In order to eliminate the toxicity of chromium sludge, hexavalent chromiumwas changed into trivalent chromium. Chromium sludge, coal and clay were used at the ratio of 0-12%:90-78%:10% to manufacture sludge bricks. Meanwhile, the influences of the sludge mass fraction, molding pressure, sintering temperature and sintering time on weight loss on ignition, chromium leaching concentration, water absorption and compressive strength of bricks were also investigated. The results indicated that the conditions for manufacturing good quality bricks was 8% sludge with 4h of sintering prepared in 20MPa molding pressure and sintered at 950°C, which can reach the national standards (HJ/T 301-2007). Furthermore, wastes were changed into resources and economical benefits were brought to the company.

Abstract: Dredging is necessary to keep rivers, harbors and lakes function normally. These dredged materials (DM) have poor geotechnical properties and are normally treated as wastes. Thus, utilization of DM for beneficial uses such as fill is being considered as an environmental-friendly and economical option. In this study a dredged material taken from Tai-hu Lake was modified by adding quicklime and by Portland cement. Water content, dry density, plasticity, and California bearing ratio (CBR) of the two types of modified soil were determined and compared. Test results show that both quicklime and cement can evidently decrease the water content and increase dry density, but the former can get better effect relatively. On the other hand, both quicklime and cement can significantly decrease the plasticity characteristics, and change the raw DM classified as CH to MH after modified, moreover, the cement has better effect on the improvement of plasticity. For the same additive content and curing days, the cement modified soil has larger CBR strength than that of the quicklime modified soil. Conclusions of the paper maybe beneficial and useful for the solidification material choose, and for practical dredged material solidification projects.

Abstract: To optimize the aeration control during the co-composting process of sewage sludge and wooden chips in a rotary drum reactor, it was proposed to study the implementation of different control strategies. A series of pilot scale experiments were carried out in a rotary drum reactor with a volume of 3.14m³, using 800 kg sewage sludge from 2^nd wastewater treatment plant of Kunming and 400 kg wooden chips collected from parks in Kunming as compost materials. Temperature, oxygen concentrations, volatile solid contents and moisture content were followed during the composting process as important variables to compare different aeration control strategies (continuous, intermittent and two stage temperature feedback aeration control strategies). The obtained results have shown that two stage temperature feedback aeration control strategy is the optimal, because it can effectively control the temperature during composting, with better moisture removal and higher organic matter degradation than the other strategies, obtaining a stabilized product with less nutrient elements losses.

Abstract: A real PCBs contaminated soil was heated at 500°C using pure nitrogen as carrier gas under different flow rate to investigate the influence of carrier gas flow rate on the thermal desorption process. After 1 hour thermal treatment, the residual PCBs in soil decreased and the removal efficiency (RE) of PCBs is up to 95.1%. The distributions of PCBs in soil under different flow rate were identical. The World Health Organization toxic equivalency quantity (WHO TEQ) of PCBs in soil got its lowest value at 400Nml/min. Tetra-and higher chlorinated PCBs desorbed to carrier gas increased with increased flow rate, while the total amount of PCBs, Tri-and lower chlorinated PCBs first increased then decreased. The distributions of PCBs in carrier gas became more closely to the raw soil with increased flow rate. The TEQ of PCBs in carrier gas increased with increased flow rate. Increased flow rate enhanced the mass transfer of PCBs in the soil but shortened the preheating time of carrier gas and the retention time of carries gas, weakening the mass transfer and degradation process in gas phase. The RE of WHO TEQ of PCDDs in treated soil decreased from 86.7% to 83.2% with increased flow rate while the RE of WHO TEQ of PCDFs decreased from 85.4% to 70.0%. After thermal treatment process, the total amount of PCDD/Fs TEQ in soil and carrier gas increase from 43.8% to 18.6% times of that in raw soil. Considering removal efficiency of PCBs and PCDD/Fs and generation of PCDD/Fs in soil and gas phase, an optimized flow rate should be set at about 400Nml/min.

Abstract: An informal landfill is an open dump that pollutes the underground environment because it lacks an impervious liner. The leakage of such a landfill is unidirectional and thus difficult to directly test. This study uses electrical imaging survey to evaluate the pollution of the underground environment of an informal landfill for municipal solid waste in Beijing. We hypothesize that every location has a specific resistivity resulting from the leachate. We use the membership function of fuzzy mathematics to quantitatively represent the pollution of the underground environment in the sanitary landfill. The results are consistent with borehole data.

Abstract: Site degradation caused from environmental pollution and wasteland has absorbed wide concern in China. In contrast to physical remediation and chemical remediation, ecological remediation (or bioremediation) is supposed to be the most environmentally sound solution for the contaminated sites and wasteland. The stone wasteland of Shimenzhai town in Qinhuangdao was investigated on the spot. Based on the terrain and ground, vegetation and soil conditions, the approaches and measures of ecological restoration were analyzed, covering the terrain fixes, soil improvement, and choice of vegetation. Some major recommendations were concluded. 1) Regarding the terrain and ground, retaining wall, shape of slope, treatment of marsh land are raised; 2) With respect to soil improvement, the improved plant and adaptation to local condition should be applied; and 3) As the choice of vegetation, the rules of plant choice are put forward, and the suitable plant and engineering measures are choose for the local stone wasteland. Finally, towards the perfect sites remediation, an excellent engineering management and assessment system should be strengthened and established in the future. Keywords: Contaminated sites; Wasteland; Qinhuangdao; Ecological remediation; Analysis

Abstract: 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.

Abstract: All of POPs chemicals in the first round list have been banned to be produced and used in China from 2009. The issue on exposure risk assessment of the obsolete production facilities for POPs is going to be discussed in this paper. Based on assessment method in the USA Region 9s Preliminary Remediation Goals, the commended model of exposure risk assessment has been reached.