生物法处理含油污泥的研究进展

随着石油产业的不断发展,导致含油污泥产量越来越大。含油污泥成分复杂,乳化严重,难于处理,直接排放对环境危害极大。生物法处理含油污泥具有成本低、无二次污染等优点,因此受到国内外学者的广泛关注。主要介绍了几种含油污泥的生物处理方法,包括:生物堆肥法、联合生物法、生物反应器法、生物修复法和生物浮选法,并对生物法处理含油污泥未来的发展提出了一些建议,以期为相关研究提供参考。     

Drying of Sewage Sludge During Composting in an Updraft Dryer with the Concept of Using Self-Energy Generated Within the System

An innovative technology for sewage treatment systems is proposed. A mixture of sewage sludge and char particle is subjected to drying in the progress of composting in an updraft column. Exothermic heat generated during composting is utilized for energy of sludge drying. The char particle in the mixture contributes to enhancement of composting and drying rate. This study presents drying and composting behaviors of sludge to examine the effect of char addition. A fundamental drying experiment was carried out by hot-air heating of the sample in a small vessel. The drying characteristic curve for a mixture of sludge and char was greater than the sample of only sludge over a whole period if the drying rates were compared with the same moisture content. The drying behavior could be analyzed with a reasonable agreement by the water front receding model. The enhancement effect of drying and composting of sludge by char addition was confirmed by examination using a pilot scale of the updraft column whose volume was 50 m³. Sludge with 400% dry base (80% wet base) in moisture content could be dried successfully to lower moisture content than 67% dry base (40% wet base) only by exothermic heat during composting without supplying any auxiliary energy from the outside, and the treatment time was reduced by mixing char in sludge. The behavior was analyzed with a satisfactory agreement by a theoretical model employing moisture diffusion parameters determined from the drying characteristic curve.     

Barriers and strategies for dry sanitation in large-scale and urban settings

Centralized waterborne sanitation faces serious social, economic and environmental sustainability challenges. Dry sanitation (DS) may ease some of those, but it is not known whether DS can be a viable solution at large scales and in urban settings. We assessed DS viability in a broad range of large scale and urban contexts in Mexico. Here, we synthesize the operational and structural barriers encountered across a diversity of sites, provide an understanding of how and why those barriers arose and propose a set of strategies through which those barriers can be addressed. We include reference to other large-scale and urban experiences outside Mexico.     

Optimization of single and mixed cultures for solid state fermentation of municipal sewage sludge

Trichoderma harzianum (Th), Phanerochaete chrysosporium ATCC 24725 (Pc) and Mucor hiemalis (Mh) isolated from three sources: wastewater; sewage sludge; and sludge cake were selected for use as compatible/incompatible single and mixed cultures in the treatment of municipal sewage sludge. Five experiments were carried out using (Pc), (Th), a mixture of (Pc/Th), (Mh) and a mixture of (Pc/Mh), in addition to a control where no micro‐organism was used. The experiments were used to evaluate their potential performance as compatible/incompatible single and mixed cultures for the treatment of municipal wastewater sewage sludge from treatment plants using solid state fermentation technique (SSF). The results showed that the best micro‐organism for composting was found to be (Th) and a mixture of (Pc/Th), while (Pc/Mh) was incompatible culture. The C/N ratio for Th changed from 8.46 to 17.8 at the end of the process, (Ph/Th) increased from 7.21 to 15.9, while (Pc/Mh) increased from 8.49 to 29. The pH value also affected by the fungal cultures which was also changed for (Th) from 4.29 to 6.8, for (Pc/Th) was changed from 7.27 to 6.7 and for (Pc/Mh) was changed from 6.6 to 5.3. Effective results were observed by using mixed culture after 19–21 days compared to other single treatments after 24–32 days.     

能量自给型城市生活垃圾堆肥系统

城市生活垃圾已成为困扰中国大部分城市居民生存环境的一个严重问题。通常的垃圾处理方法有卫生填埋、堆肥和焚烧等。文章对现有的垃圾处理方法进行了介绍。通过对国内外垃圾成分、物化性质的比较,提出了适合中国国情的垃圾处理新思路－能量自给型城市生活垃圾堆肥系统。     

Physico-chemical analysis of tannery solid waste and structural characterization of its isolated humic acids after composting

In Marrakech, solid by-products from tanneries are highly polluting, generating large amounts of nitrogenous and organic matter. In the present study composting is tested as a cost-effective method for waste management to overcome many of the environmental hazards and produce a stable, rich material for soil fertilization. Two composting trials were conducted after neutralization by ammonia or lime. The aim of the neutralization was to avoid the antimicrobial effects of the acidity in the tannery waste, thus ensuring correct composting. Different techniques such as elemental analysis and ¹³C NMR spectroscopy were applied to analyse humic acids isolated from raw and composted materials, and to monitor the process of tannery waste composting, and the stability and maturity of the final product according to the means of neutralization. Comparison of data showed similar behaviour in both trials, but the composting process appeared to be more complete following neutralization with lime. The C, H and N content decreased, while the O increased. The FTIR and ¹³C NMR spectra show the decrease of aliphatic compounds demonstrated by the reduction of absorbance around 2922 cm⁻¹ and of the resonance in the C-alkyl area around 0–55 ppm. The humic acids newly formed during composting were richer in the O–N alkyl and oxidized aromatic structures that increased almost twofold on composting after neutralization with lime. The first principal component axis PC1 (54%) separated C-aliphatic, C-carboxylic and other less stable and less polycondensed compounds such as polyphenols from the more polycondensed O–N alkyl and oxidized C-aromatic compounds.     

Bio-treatment of oily sludge: the contribution of amendment material to the content of target contaminants, and the biodegradation dynamics

The objective was to investigate the aerobic biodegradation of oily sludge generated by a flotation-flocculation unit (FFU) of an oil refinery wastewater treatment plant. Four 1m(3) pilot bioreactors with controlled air-flow were filled with FFU sludge mixed with one of the following amendments: sand (M1); matured oil compost (M2); kitchen waste compost (M3) and shredded waste wood (M4). The variables monitored were: pH, total petroleum hydrocarbons (TPHs), polycyclic aromatic hydrocarbons (PAHs), total carbon (C(tot)), total nitrogen (N(tot)) and total phosphorus (P(tot)). The reduction of TPH based on mass balance in M1, M2, M3 and M4 after 373 days of treatment was 62, 51, 74 and 49%; the reduction of PAHs was 97%, +13% (increase), 92 and 88%, respectively. The following mechanisms alone or in combination might explain the results: (i) most organics added with amendments biodegrade faster than most petroleum hydrocarbons, resulting in a relative increase in concentration of these recalcitrant contaminants; (ii) some amendments result in increased amounts of TPH and PAHs to be degraded in the mixture; (iii) sorption-desorption mechanisms involving hydrophobic compounds in the organic matrix reduce bioavailability, biodegradability and eventually extractability; (iv) mixture heterogeneity affecting sampling. Total contaminant mass reduction seems to be a better parameter than concentration to assess degradation efficiency in mixtures with high content of biodegradable amendments.     

Factors Affecting Hydrogen Production from Food Wastes by Clostridium-Rich Composts

This study used the technique of response surface approach to analyze the combined effects of heat-shocking temperature and time on anaerobic grass composts. Results indicate that the grass composts under heat-shocking temperature and time of 80°C and 3?h, respectively, could yield high populations of hydrogen-producing microorganisms. Metabolic results demonstrate that the composts are reliable, having considerable hydrogen-producing Clostridia. The multivariate analysis with response surface by considering specific hydrogen-producing potential and rate simultaneously indicate that the cultural media with Fe2+ = 132?mg/L; NH4+ = 537?mg/L; and PO43? = 1,331?mg/L were optimal for the hydrogen-producing Clostridia-rich composts using high-solids food wastes. The specific hydrogen production potential and rate were 77±3?mL?H2/gTVS and 520±20?mL?H2/g?TVS/day, respectively. The former was 38% of theoretical hydrogen-producing potential of Clostridium sp. using glucose. Of these factors, ammonium and phosphate are nutrients for the hydrogen-producing Clostridia growth while iron exerts a synergistic influence on them in the conversion of the food wastes into hydrogen.     

复合微生物菌剂对高温堆肥进程及有害气体排放的影响

研究了复合微生物菌剂用于高温堆肥对堆肥进程及期间有害气体排放量的影响. 以牛粪与稻壳为原料,分别设置接种复合微生物菌剂的处理组和空白对照组,对比了堆肥中各物理、化学和生物学指标及有害气体(甲烷和N2O)排放量. 结果表明,接种复合微生物菌剂可以加快堆体升温,延长堆体高温持续时间,缩短堆肥腐熟时间,减少有害气体(甲烷和N2O)的排放.     

Musk fragrances, DEHP and heavy metals in a 20 years old sludge treatment reed bed system

The Sludge Treatment Reed Bed (STRB) technology is a cost-efficient and environmentally friendly technology to dewater and mineralize surplus sludge from conventional wastewater treatment systems. Primary and secondary liquid sludge is loaded onto the surface of the bed over several years, where it is dewatered, mineralized and turned into a biosolid with a high dry matter content for use as an organic fertilizer on agricultural land. We analysed the concentrations of five organic micropollutants (galaxolide, tonalide, cashmeran, celestolide and DEHP) and six heavy metals (Pb, Ni, Cu, Cd, Zn and Cr) in the accumulated sludge in a 20-year old STRB in Denmark in order to assess the degradation and fate of these contaminants in a STRB and the relation to sludge composition. The results showed that the deposited sludge was dewatered to reach a dry matter content of 29%, and that up to a third of the organic content of the sludge was mineralized. The concentrations of heavy metals generally increased with depth in the vertical sludge profile due to the dewatering and mineralization of organic matter, but in all cases the concentrations were below the European Union legal limits for agricultural land disposal. The concentrations of fragrances and DEHP ranged from 10 to 9000 ng g⁻¹ dry mass. The attenuation of hydrophobic micropollutants from the top to the bottom layer of the reed bed ranged from 40 to 98%, except for tonalide which increased significantly with sludge depth, and consequently showed an unusual depth distribution of the galaxolide/tonalide ratio. This unexpected pattern may reflect changes imposed by a long storage time and/or different composition of the fresh sludge in the past. The lack of a significant decreasing DEHP concentration with sludge age might indicate that this compound is very persistent in STRBs. In conclusion the STRB was a feasible technology for sludge treatment before its land disposal.