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211.
Alkaline treatment with steel slag and NaOH addition were investigated under different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification. More solubilization of organic matters and much production of higher VFA (volatile fatty acid) in a shorter time can be achieved at pH 10 when adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under the same pH conditions. Phosphorus concentration in the supernatant increased with fermentation time and pH in NaOH addition scenarios, while in contrast most phosphorus was released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment. 相似文献
212.
213.
A biotrickling filter packed with coal slag as packing medium was continuously used for more than 9 months under high ammonia loading rates of up to 140 g/m3/h. Nitrogen mass balance and microbial community analysis were conducted to evaluate the inhibitory effects of high ammonia concentration and metabolic by-products on the rates of nitrification. Ammonia removal efficiency reached above 99% at an empty bed retention time of as low as 8 s when inlet concentrations were below 350 ppm. The maximum and critical elimination capacities of the biotrickling filter were 118 g/m3/h and 108.1 g/m3/h, respectively. Kinetics analysis results showed that less than 2.5 s was required for the biotrickling filter with pH control to treat ammonia at concentrations of up to 500 ppm in compliance with the Taiwan EPA standard (outlet NH3 < 1 ppm). Results of mass balance and microbial community analysis indicated that complete removal was mainly contributed by the activities of autotrophic ammonia oxidizing bacteria and not by physical absorption or adsorption at low loading rates. However, at high inlet loadings, ammonium became the dominant by-product due to inhibitory effects of high ammonia concentration on the bacterial community. 相似文献
214.
从银铅锌废渣中回收硝酸银的研究 总被引:1,自引:0,他引:1
介绍了用灼烧、浸取、沉淀、溶转和离子交换等方法,从银铅锌废渣中直接回收硝酸银,收率可达80.12%,AgNO3纯度为99.9%。考察了试料粒度、FeCl3质量浓度、溶液酸度、固液比,反应温度及浸取时间对银浸出率的影响。 相似文献
215.
Metallic-phase lead in slag of municipal solid waste incineration ash and leaching characteristics 总被引:2,自引:0,他引:2
Metallic phases in slags and their influence on the leaching characteristics were investigated. The proportions of metallic
phase in four slags were 0.028%, 0.24%, 1.87%, and 3.05% by weight. The lead content was 10–248 mg/kg in bulk slag after metal
removal, while in the metallic phase it was 579–7390 mg/kg. Lead concentrations in the metallic phase were more than ten times
higher than in slags after metal removal. Lead was distributed in the metallic phase at 2.0%, 8.3%, 10.3%, and 47.4%. The
concentrations of all metallic elements in metallic phases were much higher than in bulk slag. Iron, copper, and nickel had
accumulated in magnetic metals, while aluminum and zinc were found in nonmagnetic metals. As regards chromium, manganese,
lead, and tin, the proportion of metallic phases depended on the slag samples. By removing metallic phases, both water and
pH 4 leachable lead decreased. The basic principles of melting residues containing lead are the separation of lead as a metal
in reductive melting, and the containment of lead ions into uniform glassy particles in oxidization melting. Melting slag
can be seen to contribute to environmental preservation by facilitating the recycling of materials through the separation
of metals from melting slag.
Received: February 21, 2000 / Accepted: July 27, 2000 相似文献
216.
217.
医疗废物焚烧处置过程中关键参数研究 总被引:4,自引:0,他引:4
针对我国相关标准和技术规范在医疗废物焚烧处置中的问题,以控制二英、燃烧效果、残渣处置为关键目标,从二英控制机理、工况设计、设备选择和残渣处置等焚烧的关键环节进行深入分析。提出:一燃室、二燃室的最佳温度分别为850~870和1000~1200℃;烟气停留时间大于2s,但可根据实际情况延长;湍流程度的雷诺数大于1×104,当雷诺数大于5×104时,焚烧效率更高;急冷装置在180~550℃时烟气停留时间应小于1 5s,布袋除尘器最佳工作温度为120~150℃;残渣、飞灰和底渣中的w(PCDD DFs)(以TEQ计,下同)应分别小于1 0,0 3和0 5ng g。当底渣中的w(PCDD DFs)高于0 3ng g时,则当作危险废物处理。 相似文献
218.
白泥对填埋场垃圾降解的影响实验研究 总被引:1,自引:0,他引:1
在4个相同的密封聚乙烯塑料罐中,分别装填相同组分和重量的青岛市居民区的生活垃圾,并且在4个罐中按不同比例添加白泥,与垃圾混合均匀。实验模拟填埋场的环境条件。定期监测4个罐渗滤液的水质变化,分析比较白泥的添加及添加量的多少对渗滤液的衰减的影响。实验结果表明,白泥的添加能够向反应系统提供一定数量的碱度,可以防止反应系统因出现酸过度累积而受到抑制,在一定程度上加快了垃圾的降解进程。这不仅对于减轻渗滤液处理设施的负荷、加速填埋场的稳定化起着积极作用,而且可以为白泥的资源化利用提供一个可行的途径。 相似文献
219.
220.
Fe~0体系降解2,4二氯酚的影响因素及其反应机理 总被引:1,自引:0,他引:1
采用铁屑、炉渣及河砂混合介质降解2,4-二氯酚(2,4-DCP)模拟废水,研究铁屑粒径、铁屑投加量、铁屑与炉渣配比、pH值等因素对2,4-DCP脱氯效果的影响,探讨Fe0体系降解2,4-DCP的反应机理。结果表明,铁屑粒径、铁屑投加量、铁屑与炉渣配比、pH对2,4-DCP脱氯效果均有显著影响,在铁屑粒径为2~5 mm、不改变废水pH、铁屑与炉渣质量比为31∶9条件下,Fe0体系对2,4-DCP去除率高达97%。2,4-DCP经脱氯后主要产物为2-氯酚、4-氯酚和苯酚,反应后废水的可生化性明显提高,利于后续的生物处理。 相似文献