RESUMEN
The aim of this study was to find a feasible method for the treatment of solid waste generated in the remote rural, where the transportation costs are prohibitive and the resources to construct and maintain conventional treatment plants are not available. This process, consisted of two types of simulated bioreactor landfill (one was recirculated bioreactor landfill, and the other was comprised of fresh and aged refuse reactor) and a soil infiltration system, was operated in ambient temperature for 180 days all together. After treated by the system of fresh and aged refuse reactor, the refuse and leachate reached a strongly degraded and stable state. The remaining leachate can be treated by the soil infiltration system, and 87.5 ± 2.1%, 98.6 ± 1.0% and 95.7 ± 1.7% were achieved by 60 cm soil depths for organic matter, ammonium nitrogen and total nitrogen removal, respectively.
Asunto(s)
Reactores Biológicos , Eliminación de Residuos/instrumentación , Eliminación de Residuos/métodos , Población Rural , Suelo/análisis , Contaminantes Químicos del Agua/análisis , China , Nitrógeno/aislamiento & purificación , Contaminantes Químicos del Agua/metabolismoRESUMEN
Two extraction reagents, hydrochloric acid (HCl) and acid ammonium oxalate solution (Tamm's reagent), were used to evaluate the redox state of iron in municipal solid waste (MSW) with different deposit ages. Orthogonal experiments were conducted to optimize the extraction conditions for extractable iron speciation (ferric and ferrous) in MSW. The optimal extraction conditions for HCl were determined as follows: the liquid-to-solid ratio was set at 100, and then the samples were extracted at the shaking speed of 200 rpm at 35 degrees C for 60 min by 1.00 M HCl. For Tamm's reagent, the optimal extraction conditions were extracted at the shaking speed of 175 rpm at 30 degrees C for 12 h with the same liquid-to-solid ratio. However, Tamm's reagent extraction is much more laborious and time-consuming. Thus the HC1 extraction might be a better choice for the evaluation of the redox state of iron in MSW. The results also showed that the yield of extractable iron increased with deposited age. About 60-83% of extractable iron was presented as ferrous in the MSW deposited for 1-8 years. This study supplied a tool for investigating the role of iron on the fate of pollutants in the landfill.
Asunto(s)
Compuestos Ferrosos/aislamiento & purificación , Eliminación de Residuos , Compuestos Ferrosos/clasificación , Ácido Clorhídrico/química , Oxidación-ReducciónRESUMEN
OBJECTIVE: To evaluate the clinical efficacy of flow-through hybridization and gene chip (HybriMax) on female low genital human papillomavirus (HPV) detection and to identify the most common HPV genotypes. METHODS: Five hundred and ninety-one of 7520 women who received cervical cancer screening in China-Japan Friendship Hospital during Jun 2004 to May 2005 were selected for 21 genotypes HPV detecting by HybriMax, including 138 women with normal cytological diagnosis and 453 women with abnormal cytological diagnosis. The abnormal patients were classified into groups according to their histological diagnosis as chronic cervicitis, cervical intraepithelial neoplasia (CIN) I, II, III, cervical cancer and condyloma acuminata. Among them 413 women were tested with HC-II for 13 types of high-risk HPV, and 101 paraffin-embedded specimens from these 453 patients were detected for HPV16, 18 with in situ hybridization (ISH). The accordance of the results was compared. The infection rates of each HPV type for each group were calculated. RESULTS: The total accordant rate of HybriMax and HC-II on 13 types of high-risk HPV detecting was 92.5% (382/413) and was 100.0% in group of cancer. The accordance was good, and the Kappa index (KI) was as below: overall 0.814, in normal group 0.750, in chronic cervicitis 0.781, in CIN I 0.755, in CIN II 0.619, in CIN III 0.548, in condyloma acuminata 0.800. The accordant rate of HybriMax and ISH was 89.1% (90/101), and KI was 0.766. The 10 most common genotypes were (in descending sequences): in normal group 16, 68, 18, 52, 58, 11, 53, 31, 39, 33; in abnormal group 16, 52, 58, 18, 33, 31, 81, 53, 68, 66, in cervical cancer 16, 18, 52, 58, 33, 66, 68, 31, 51, 53. CONCLUSIONS: HybriMax has good accordance to HC-II and ISH for HPV detection. It provides useful information on viral genotype and is more suitable for clinical use. The 6 most common genotypes in abnormal cytological group are 16, 18, 52, 58, 33, 31.