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《再生资源与循环经济》2016,(8)
膜生物反应器(MBR)是一种新兴的污水高效处理工艺,其脱氮效能优化和污泥特性也是相关研究热点之一。研究采用间歇曝气的运行方式提高一体式MBR的脱氮效率,并考察了不同工况下活性污泥浓度及脱氮酶活性,结果表明,间歇曝气有效地强化了MBR的反硝化作用,显著地增强了其脱氮效能,而NH_4~+-N及COD的去除几乎未受影响;活性污泥浓度增长缓慢平稳,脱氢酶活性因污泥龄的延长有小幅下降,间歇曝气未显著影响污泥特性。 相似文献
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采用蔗糖作为共代谢基质与一体式好氧膜生物反应器(MBR)工艺相结合处理二甲基亚砜(DMSO)废水。考察了装置的污泥驯化效果、DMSO去除率、污泥的性能、HRT和冲击负荷对DMSO去除率的影响。试验结果表明:驯化第29天,DMSO去除率达98.5%,表明MBR内的污泥已驯化成功;在MBR运行的正式期,当DMSO处于高负荷状态时,DMSO去除率较低;随蔗糖加入量的增加,DMSO去除率逐渐提高,最终恢复到DMSO高负荷冲击前的DMSO去除效果;正常运行时,装置进水ρ(DMSO)=257~1 448 mg/L(平均值为718 mg/L)、出水ρ(DMSO)=6~22 mg/L(平均值为7 mg/L),DMSO去除率为96.4%~99.6%(平均值为98.9%);在MBR运行的正式期,污泥体积指数小于100 mL/g,表明污泥的沉降性能较好,MLVSS/MLSS较高,表明污泥的活性高,MBR内MLSS的平均值为5.52 g/L,MLVSS的平均值为4.78 g/L;MBR适宜的HRT为12 h。 相似文献
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石化废水剩余污泥在厌氧消化时,污泥停留时间长,且产气量较低,并且反应器容积较大,所需资金投入较高.污泥厌氧消化预处理能够改变污泥特性,缩短了后续消化时间,提高甲烷产量,减少剩余污泥量.综述了各种污泥预处理技术的最新进展,分析了石化污泥厌氧消化预处理的可行性. 相似文献
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火电厂采用膜法实现城市中水回用的工程实践 总被引:1,自引:0,他引:1
介绍了膜法及其在城市污(中)水回用方面的技术发展、原理、工艺,并结合工程实践对火电厂采用的膜生物工艺(MBR)进行了技术经济分析和比较. 相似文献
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Lake sediment cores were analyzedto study the history of mercury (Hg) pollution andparticularly to determine whether recent sedimentconcentrations have declined in response todeclining atmospheric deposition of Hg. Sedimentcores from 6 forest lakes distributed fromsouthern to northern Sweden and 3 northernmountain lakes were analyzed for Hg using CVAAS. A400 cm sediment profile from Måkevatten insouthwest Sweden indicates that the onset of Hgpollution occurred in the 18th century. Anindisputable increase in Hg concentrationsoccurred concurrent with the appearance ofspheroidal carbonaceous flyash particles (SCP)derived from fossil-fuel combustion, in themid-19th century. There is a strong correlationbetween Hg and SCP concentrations in the sedimentcores (r=0.67 to 0.91), which suggests a strongrelationship between historical Hg pollution andfossil fuel burning. In contrast to sediment corestaken in 1979, maximum Hg concentrations are nowobserved below the sediment surface and declinetowards the sediment surface. This study confirmsthat reductions in atmospheric deposition of Hgover Sweden have resulted in a decreased transferof total Hg to aquatic environments as reflectedby lake sediments, and that lake sediment profilesof Hg concentrations reflect relative trends inthe atmospheric deposition of Hg rather thanpost-depositional diagenetic processes. 相似文献
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The deposition patterns of Mn, Fe, Cr, Sb, Zn and As wereinterpreted together with enrichment factor calculations. Samples collected around iron-steel plant had very high concentrations and EF values of Mn, Fe, Cr, Sb and Zn implying that these plants are serious pollution sources in the region. High As concentrations around the settlementareas showed that coal combustion is another important anthropogenic source in the region. 相似文献
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The SO4–S and NO3–N concentrations and pH in bulk precipitation, throughfall, stemflow and soil water for the 1994–2004 period were studied
in pine forests in Latvia (Rucava and Taurene Integrated Monitoring stations). The SO4–S and NO3–N concentrations decreased over the study period, simultaneously with a decrease of acidity in precipitation. The changes
were more evident in the western part of Latvia, probably due to declining long-range air pollution from West Europe. The
trend of decreasing sulphate concentrations and increasing pH in precipitation were not followed by respective changes in
soil water. In the upper soil horizon sulphate ion concentrations and acidity increased in soil water. Over the observation
period, nitrate concentrations also showed an increasing trend in soil water at Rucava and Taurene, but these changes were
not statistically significant. 相似文献
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The research concerns the Wielkopolski National Park (West Poland), which suffered a huge human impact in the 1970s and 1980s
owing to the nearby location of an industrial plant. Since then, fundamental technological changes that it introduced into
its production of phosphate fertilizers have radically reduced the amount of pollution emitted. A three-year study (2002–2004)
of fluorides in precipitation in open terrain and under tree crowns showed their concentrations to range from levels below
the detection limit (0.003 mg/l) to 0.560 mg/l. Those registered under tree crowns were several times higher and indicated
substantial dry deposition of fluorides on the trees. The highest values were recorded in 2003, with 43% of samples ranging
from 0.01 to 0.05 mg/l, and with 51% of throughfall ranging from 0.10 to 0.50 mg/l. A strong connection was shown to exist
between fluoride and sulphate concentrations in the precipitation. An analysis was made of the available data on F concentrations
in the air and the dust levels around the factory, but these figures did not show an unequivocal effect on F concentrations
in precipitation. A great similarity was found to occur between the fluoride content in rainwater in the Wielkopolski National
Park and in the centre of the nearby Poznań metropolitan area, which indicates that there are also other F sources besides
the local factory. 相似文献
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Michikazu Kojima Aya Yoshida So Sasaki 《Journal of Material Cycles and Waste Management》2009,11(3):263-269
Developing Asian countries have started to apply the principle of extended producer responsibility (EPR) to electronics and
electrical equipment waste (e-waste). This policy approach aims to give electronic appliance manufacturers and importers responsibility
for the collection and recycling of discarded electronic equipment. China and Thailand have drafted regulations on the recycling
of e-waste with common characteristics such as the financial responsibility of producers and subsidies for collection. Although
the proposed system is sensible, taking into account the fact that e-waste is a market-traded commodity, there are two major
difficulties in implementing EPR in developing countries. First, it may be difficult for governments to collect funds from
producers or importers if smuggled, imitation, or small shop-assembled products have a large share in the market. Second,
the system creates incentives for collectors and recyclers to over-report the amount of collected e-waste in order to gain
extra subsidies from the fund. Other policy measures such as the enforcement of pollution control regulations on informal
recyclers, the prevention of smuggling, and the protection of intellectual property rights should accompany EPR policies. 相似文献
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The objective of this paper is to estimate the future projection of computer waste in India and to subsequently analyze their flow at the end of their useful phase. For this purpose, the study utilizes the logistic model-based approach proposed by Yang and Williams to forecast future trends in computer waste. The model estimates future projection of computer penetration rate utilizing their first lifespan distribution and historical sales data. A bounding analysis on the future carrying capacity was simulated using the three parameter logistic curve. The observed obsolete generation quantities from the extrapolated penetration rates are then used to model the disposal phase. The results of the bounding analysis indicate that in the year 2020, around 41–152 million units of computers will become obsolete. The obsolete computer generation quantities are then used to estimate the End-of-Life outflows by utilizing a time-series multiple lifespan model. Even a conservative estimate of the future recycling capacity of PCs will reach upwards of 30 million units during 2025. Apparently, more than 150 million units could be potentially recycled in the upper bound case. However, considering significant future investment in the e-waste recycling sector from all stakeholders in India, we propose a logistic growth in the recycling rate and estimate the requirement of recycling capacity between 60 and 400 million units for the lower and upper bound case during 2025. Finally, we compare the future obsolete PC generation amount of the US and India. 相似文献
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Mohee R 《Waste management (New York, N.Y.)》2005,25(6):575-581
This study was initiated to characterize solid and liquid wastes generated in healthcare institutions and to provide a framework for the safe management of these wastes. The project was carried at three major medical institutions, namely, the Jeetoo Hospital, the Sir Seewoosagur Ramgoolam National (SSRN) Hospital and the Clinic Mauricienne. A waste audit carried out at these sites revealed that approximately 10% of solid wastes was hazardous in nature, consisting mainly of infectious, pathological and chemical wastes. The average amount of hazardous wastes per patient per day was found to be 0.072 kg at Jeetoo hospital, 0.091 kg at SSRN hospital and 0.179 kg at the clinic. The amount of hazardous wastes generated as a function of the number of occupied beds was found to follow a relationship of type y=0.0006x-0.19, where y was the amount of hazardous wastes generated per bed per day and x was the number of occupied beds. The waste quantifying process also revealed that at SSRN Hospital, 0.654 m(3) of water was being consumed per patient per day and the amount of wastewater produced was 500 m(3)/day. Further analysis revealed that the wastewater was polluting with chemical oxygen demand (COD), biological oxygen demand (BOD(5)), total suspended solids (TSS) and coliform content well above permissible limits. 相似文献
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Sumikura Yuichiro Katsumi Takeshi 《Journal of Material Cycles and Waste Management》2022,24(4):1216-1227
Journal of Material Cycles and Waste Management - The status of material reuse and recycling in Japan is reviewed with an emphasis on the efforts by the national government. First, the national... 相似文献
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Within the European monitoring network (EMEP, ) several different sampling procedures for measuring the main air components have been applied. This has contributed to systematic
concentration differences and a comparability problem. Since 1997 co-located experiments in 15 countries have been carried
out to quantify these differences. In addition, three major measurement campaigns were organized by EMEP between 1985 and
1991. Differences among results depend on the concentration level and methods used. The decrease in SO2 concentrations over the last twenty years has placed greater demands on the methodology. Absorbing solutions methods for
SO2, (H2O2 and tetrachloromercurate (TCM)) typically have higher detection limits than the reference method, which uses KOH impregnated
filters. The TCM method also has problems with negative interference, especially in summertime. UV fluorescence monitors have
in a few cases proven to give good results, but interferences, detection limit and poor maintenance can be problems. For NO2, many countries are using the TGS absorption solution method, which has a higher detection limit than the reference method
using NaI impregnated glass sinters. The Salzmann method gives unreliable results at concentrations below 1 μgN/m3, and even at higher concentrations the uncertainty is rather unsatisfactory. The chemiluminescence monitor with molybdenum
converters tends to systematically overestimate NO2 concentrations, possibly because zero-drift problems and the non-specific response to NO2. Particulate sulphate measurements in general have lower bias and uncertainties than gas and other aerosol measurements. 相似文献
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A wide variety of antibiotics have been detected in natural water samples and this is of potential concern because of the adverse environmental effects of such antibiotic residues. One of the main sources of antibiotics effluence to the surrounding environment is livestock manures which often contain elevated concentrations of veterinary antibiotics (VAs) which survive digestion in the animal stomach following application in animal husbandry practices. In Korea, livestock manures are normally used for compost production indicating that there is potential for antibiotic release to the environment through compost application to agricultural lands. Therefore, reduction of the amount of VAs in composts is crucial. The purpose of this study was to understand the influence of the composting process and the components of the compost on the levels of three common classes of antibiotics (tetracyclines, sulfonamides, and macrolides). Composted materials at different stages of composting were collected from compost manufacturing plants and the variation in antibiotic concentrations was determined. Three different antibiotics, chlortetracycline (CTC), sulfamethazine (SMZ), and tylosin (TYL) at three different concentrations (2, 10, and 20 mg kg−1) were also applied to a mixture of pig manure and sawdust and the mixtures incubated using a laboratory scale composting apparatus to monitor the changes in antibiotic concentrations during composting together with the physicochemical properties of the composts. During composting, in both field and lab-scale investigations, the concentrations of all three different antibiotics declined below the relevant Korean guideline values (0.8 mg kg−1 for tetracyclines, 0.2 mg kg−1 for sulfonamides and 1.0 mg kg−1 for macrolides). The decline of tetracycline and sulfonamide concentrations was highly dependent on the presence of sawdust while there was no influence of sawdust on TYL decline. 相似文献