绿色润滑剂的研究及进展

文章综述了国内外绿色润滑剂的研究及发展现状;简要地介绍了绿色润滑剂的特点、应用情况以及一些常用的生物降解性和毒性及生态毒性的测试方法与标准;分析了其发展所面临的挑战;并展望了其在2l世纪的发展趋势与应用前景。     

Studies on the toxic effects of pentachlorophenol on the biological activity of anaerobic granular sludge

In order to explore the pathway of the anaerobic biotreatment of the wastewater containing pentachlorophenol (PCP) and ensure the normal operation of Upflow Anaerobic Sludge Blanket (UASB) reactor, the anaerobic sludge under different acclimation conditions were selected to seed and start up UASB reactors. Anaerobic toxicity assays were employed to study the biological activity, the tolerance and the capacity to degrade PCP of different anaerobic granular sludge from UASB reactors. Results showed that the anaerobic granular sludge acclimated to chlorophenols (CPs) could degrade PCP more quickly (up to 9.50mg-PCPg(-1)TVSd(-1)). And the anaerobic granular sludge without acclimation to CPs had only a little activity of degrading PCP (less than 0.07mg-PCPg(-1)TVSd(-1)). Different PCP concentrations (2, 4, 6, 8mgL(-1)) had different inhibition effects on glucose utilization, volatile fatted acidity (VFA)-degrading and methanogens activity of PCP degradation anaerobic granular sludge, and the biological activity declined with the increase in PCP concentration. The methanogens activity suffered inhibition from PCP more easily. The different acclimation patterns of seeded sludge had distinctly different effects on biological activity of the degradation of PCP of anaerobic granular sludge from UASB reactors. The biological activity of the anaerobic granular sludge acclimated to PCP only was also inhibited. This inhibition was weak compared to that of anaerobic granular sludge acclimated to CPs, further, the activity could recover more quickly in this case. In the same reactor, the anaerobic granular sludge from the mid and base layers showed higher tolerance to PCP than that from super layer or if the sludge is unacclimated to CPs, and the corresponding recovery time of the biological activity in the mid and base layers were short. Acetate-utilizing methanogens and syntrophic propinate degraders were sensitive to PCP, compared to syntrophic butyrate degraders.     

Health risks of residential wood heat

The resurgence in the use of wood in the United States for residential heating has been accompanied by a dramatic increase in deaths and injuries from residential fires. Toxic materials present in woodsmoke also appear to present a significant public health hazard. As a result of these factors, production of residential wood heat can be up to two orders of magnitude more hazardous than generation of an equivalent amount of electric energy at a coal-fired power plant. Proper care in installation and operation of wood stoves, as well as technological innovations that control wood-stove emissions, can greatly reduce the health and safety hazards of residential heating with wood.     

The Water Quality of some Tropical Freshwater Bodies in Uyo (Nigeria) Receiving Municipal Effluents, Slaughter-House Washings and Agricultural Land Drainage

The water quality of some tropical fresh-water bodies in Uyo (Nigeria) was investigated for two years in relation to point and non-point source city effluents and slaughter-house washings discharged into them. Streams which received city effluents and slaughter-house washings were degraded in quality with acidic water (pH =5.26±0.83 to 6.20±0.56), low oxygenation (2.46±1.30 to 3.88±0.29 mgl^–1), high biochemical oxygen demand (4.96±0.66 to 8.20±0.82 mgl^–1) and chemical oxygen demand (88.60±3.50 to 146.36±9.86 mgl^–1) than non-effluent receiving streams. High acidity in streams is due mainly to the acidic nature of underground water which replenishes the streams. Nutrient levels were high indicating enrichment from highly fertilized farmlands and slaughter-house washings. The concentrations of most of the hydrochemical variables were significantly lower in non-effluent than effluent-receiving streams. Some of the hydrochemical variables (total alkalinity, dissolved oxygen, nitrate, phosphate and conductivity) exhibited pronounced seasonality regimes with significant correlations with rainfall indicating its influence on the chemical hydrology of the water bodies. Land use in the catchment influenced water quality through inflow of nutrients, organic and inorganic contaminants and siltation. Pollution in the impacted streams is attributed mainly to episodic events.     

Social trends of the people of the region of Eastern Macedonia and Thrace-Greece: about the potential of using biofuels from forest products residues

In the framework of enquiry of biomass usage possibilities in our country, a research was made through the whole Eastern Macedonia region, related to disposal possibilities from the production conveyors and usage possibilities from the region’s residents and businessmen, of biofuels that come from mechanical wood treatment residues and from the residues of agricultural production, in wooden form, known with the term wood pellets or wood briquettes. From the present study, it came to light that there is an intense interest for direct personal usage and application of biomass for the residents or occupational spaces heating. The necessary biomass quantity for the entire region’s households is estimated up to 205,520 t. From the biomass usage as a combustible material, a 680 €/year and household about, is made. The potential investments that will be made to the region seem to have a very short depreciation, but a business plan and a marketing plan syntax are considered as necessary for the result’s maximisation.     

催化铁应用于草甘膦废水处理工艺改造的可行性研究

针对某化工厂草甘膦废水经厌氧-好氧生物处理后出水总磷浓度高,无法达到该化工区污水纳管标准的情况,应用催化铁方法对该废水现有处理工艺进行改造以提高出水水质。考察了催化铁方法对原处理工艺不同处理工段出水中磷的去除效果,发现该法可有效地去除生物厌氧池出水的总磷及正磷盐,去除率分别达到52．7％和83．13％以上,且使废水的BOD5／COD值显著提高,可从0．08提高至0．31,增强了废水的可生物降解性,有利于后续好氧生物处理的进行。研究表明在原处理工艺的厌氧池后增加催化铁处理段能明显提高最终出水水质。     

Substituting energy crops with organic wastes and agro-industrial residues for biogas production

In this study, industrial and agro-industrial by-products and residues (BRs), animal manures (AMs), and various types of organic wastes (OWs) were analyzed to evaluate their suitability as substitutes for energy crops (ECs) in biogas production. A comparison between the costs of the volume of biogas that can be produced from each substrate was presented with respect to the prices of the substrates in the Italian market. Furthermore, four different feeding mixtures were compared with a mixture of EC and swine manure (Mixture A) used in a full-scale plant in Italy. Swine manure is always included as a basic substrate in the feeding mixtures, because many of the Italian biogas plants are connected to farms. When EC were partially substituted with BR (Mixture B), the cost (0.28 € Nm⁻³) of the volume of biogas of Mixture A dropped to 0.18 € Nm⁻³. Furthermore, when the organic fraction of municipal solid waste (OFMSW) and olive oil sludge (OS) were used as possible solutions (Mixtures C and D), the costs of the volume of biogas were −0.20 and 0.11 € Nm⁻³, respectively. The negative price signifies that operators earn money for treating the waste. For the fifth mix (Mixture E) of the OFMSW with a high solid substrate, such as glycerin from biodiesel production, the resulting cost of the volume of biogas produced was −0.09 € Nm⁻³. By comparing these figures, it is evident that the biogas plants at farm level are good candidates for treating organic residues of both municipalities and the agro-industrial sector in a cost-effective way, and in providing territorially diffused electric and thermal power. This may represent a potential development for agrarian economy.     

1996年中国厌氧技术研究新进展

本文综合叙述了１９９６年度国内关于厌氧消化技术的研究,包括基础理论的研究,消化工艺的研究,以及厌氧消化应用于各种废物处理的研究。     

THERMAL GRADIENTS IN RIVERS AND RESERVOIRS DUE TO HEATED PLANT EFFLUENTS1

ABSTRACT The direction of heated effluents from large thermal power plants into streams and lakes has been a matter of public concern for some time, and the collection of prototype data related to the hydraulic aspects has taken on massive proportions. Unfortunately, most of the data are proprietary and not available for public analysis. The authors have endeavored to collect such data as are available to them for the initiation of steps toward generalization and the discussion of some of the more evident hydraulic considerations. The study is primarily concerned with rivers, including estuaries, with some interest in cooling ponds.     

Heavy metal removal from industrial effluents by sorption on cross-linked starch: chemical study and impact on water toxicity

Batch sorption experiments using a starch-based sorbent were carried out for the removal of heavy metals present in industrial water discharges. The influence of contact time, mass of sorbent and pollutant load was investigated. Pollutant removal was dependent on the mass of sorbent and contact time, but independent of the contaminant load. The process was uniform, rapid and efficient. Sorption reached equilibrium in 60 min irrespective of the metal considered (e.g. Zn, Pb, Cu, Ni, Fe and Cd), reducing concentrations below those permitted by law. The material also removed residual turbidity and led to a significant decrease in the residual chemical oxygen demand (COD) present in the industrial water discharge. The germination success of lettuce (Lactuca sativa) was used as a laboratory indicator of phytotoxicity. The results show that the sorption using a starch-based sorbent as non-conventional material, is a viable alternative for treating industrial wastewaters.     

The removal of lignin and phenol from paper mill effluents by electrocoagulation

This study aims to investigate the treatment of paper mill effluents using electrocoagulation. Removal of lignin, phenol, chemical oxygen demand (COD) and biological oxygen demand (BOD) from paper mill effluents was investigated at various current intensities by using different electrodes (Al and Fe) and at various electrolysis times (1.0, 2.5, 5.0 and 7.5min). It was observed that the experiments carried out at 12V, an electrolysis time of 2min and a current intensity of 77.13mA were sufficient for the removal of these pollutants with each electrode. The removal capacities of the process using an Al electrode were 80% of lignin, 98% of phenol, 70% of BOD, and 75% of COD after 7.5min. Using an Fe electrode the removal capacities were 92%, 93%, 80% and 55%, respectively. In addition, it was found that removal of lignin, phenol, BOD and COD increased with increasing current intensity. In the experiments carried out at different current intensities, higher removal can be explained through a decrease in intra-resistance of solution and consequently an increase at the transfer speed of organic species to electrodes. It was also found that Al electrode performs higher efficiency than Fe electrode except for COD removal. However, the time required for removal of BOD was more than that of COD. The results suggest that electrocoagulation could be considered as an effective alternative to paper mill effluents treatment.     

Anaerobic digestion of dairy manure with enhanced ammonia removal

Poor ammonia-nitrogen removal in methanogenic anaerobic reactors digesting animal manure has been reported as an important disadvantage of anaerobic digestion (AD) in several studies. Development of anaerobic processes that are capable of producing reduced ammonia-nitrogen levels in their effluent is one of the areas where further research must be pursued if AD technology is to be made more effective and economically advantageous. One approach to removing ammonia from anaerobically digested effluents is the forced precipitation of magnesium ammonium phosphate hexahydrate (MgNH4PO4 x 6H2O), commonly called struvite. Struvite is a valuable plant nutrient source for nitrogen and phosphorus since it releases them slowly and has non-burning features because of its low solubility in water. This study investigated coupling AD and controlled struvite precipitation in the same reactor to minimize the nitrogen removal costs and possibly increase the performance of the AD by reducing the ammonia concentration which has an adverse effect on anaerobic bacteria. The results indicated that up to 19% extra COD and almost 11% extra NH3 removals were achieved relative to a control by adding 1750 mg/L of MgCl2 x 6H2O to the anaerobic reactor.     

Anaerobic ammonium oxidation by Nitrosomonas spp. and anammox bacteria in a sequencing batch reactor

A sequencing batch reactor (SBR) was inoculated with mixed nitrifying bacteria from an anoxic tank at the conventional activated sludge wastewater treatment plant in Nongkhaem, Bangkok, Thailand. This enriched nitrifying culture was maintained under anaerobic conditions using ammonium (NH(4)(+)) as an electron donor and nitrite (NO(2)(-)) as an electron acceptor. Autotrophic ammonium oxidizing bacteria survived under these conditions. The enrichment period for anammox culture was over 100 days. Both ammonium and nitrite conversion rates were proportional to the biomass of ammonium oxidizing bacteria; rates were 0.08 g N/gV SS/d and 0.05 g N/g VSS/d for ammonium and nitrite, respectively, in a culture maintained for 3 months at 42 mg N/L ammonium. The nitrogen transformation rate at a ratio of NH(4)(+)-N to NO(2)(-)-N of 1:1.38 was faster, and effluent nitrogen levels were lower, than at ratios of 1:0.671, 1:2.18, and 1:3.05. Fluorescent in situ hybridization (FISH) was used to identify specific autotrophic ammonium oxidizing bacteria (Nitrosomonas spp., Candidatus Brocadia anammoxidans, and Candidatus Kuenenia stuttgartiensis). The ammonium oxidizing culture maintained at 42 mg N/L ammonium was enriched for Nitrosomonas spp. (30%) over Candidati B. anammoxidans and K. stuttgartiensis (2.1%) while the culture maintained at 210 mg N/L ammonium was dominated by Candidati B. anammoxidans and K. stuttgartiensis (85.6%). The specific nitrogen removal rate of anammox bacteria (0.6 g N/g anammox VSS/d) was significantly higher than that of ammonium oxidizing bacteria (0.4 g N/g Nitrosomonas VSS/d). Anammox bacteria removed up to 979 mg N/L/d of total nitrogen (ammonium:nitrite concentrations, 397:582 mg N/L). These results suggest significant promise of this approach for application to wastewater with high nitrogen but low carbon content, such as that found in Bangkok.     

厌氧消化治理造纸黑液

造纸黑液是最严重的水污染物之一,目前国内还没有一种能彻底治理黑液的方法,球溪河糖厂经过多年探索,试验,工业化治理运行,认为厌氧消化是治理中小型,亚铵法纸厂制浆黑液适宜方法。