Leachates generated in Hong Kong landfill sites contain high strength of ammonium-nitrogen (NH4+-N) in the range of 2000[1]/5000mg l-1, which could be used to produce nitrogen-fertilizer. To recover the NH4+-N from the leachate, alab-scale study was performed to investigate the efficiency of magnesium ammonium phosphate (MAP) precipitationusing three combinations of chemicals: MgCl2

Leachate samples were collected from the West New Territory Landfill (WENT), Hong Kong, and characterized in the laboratory. The analytical results confirmed that it has a typical nature ofaged leachate with a low BOD5/COD ratio Of O.22 and a high strength of ammonia-nitrogen around 5G/L. A lab-scale study was conducted to investigate the inhibition of microbial activity of the activated sludge. In the first test. glucose-based synthetic wastewater Was used in two parallel reactors. The experimental results demonstrated that COD removal declined from 95.1 to 79.1% activated sludge. In the first test. glucose-based synthetic wastewater Was used in two parallel reactors. The experimental results demonstrated that COD removal declined from 95.1 to 79.1% activated sludge. In the first test. glucose-based synthetic wastewater Was used in two parallel reactors. The experimental results demonstrated that COD removal declined from 95.1 to 79.1% and the dehydrogenase activity of the sludge decreased from 11.04 to 4.22μg TF/mg mixed Iiquor suspended solids (MLSS), when the ammonia-nitrogen concentration increased from 50mg/L to 800mg/L progressively. The remaining NH3+-N residue in the treated wastewater increased from 0.58mg/L to 649mg/L extensively. In the second test. mixed wastewater samples containing glucose and raw leachate were fed into six parallel biological reactors and operated on batch mode. The experimental results showed COD removal decreased from 97.7 to 78.1% and the dehydrogenase activity decreased from 9.29 to 4.93μg triphenyl formazon (TF)/mg MLSS, respectively. when the ammonia-nitrogen concentration increased within the same range. Mierobial inhibition could alSO be substantiated by a decrease of specific oxygen uptake rate (SOUR) from 68 to 45mg O2/g MLSS. These results suggested leachate containing high-strength ammonia-nitrogen should be pretreated to art acceptable NH4+-N level before it is fed into biological reactors.

The landfill leachate in Hong Kong usually contains quite high NH4+-N concentration, which is well known to inhibit nitrifica-tion in biological treatment processes. A common pre-treatment for reducing high strength of ammonium (NH4+-N) is by an air-stripping process. However, there are some operational problems such as carbonate scaling in the process of stripping. For this reason, some technical alternatives for NH4+-N removal from leachate need to be studied. In this study, a bench-scale experiment was initiated to investigate the feasibility of selectively precipitating NH4 +

研究了高温/中温两相厌氧消化反应器系统用以同时处理污泥与不同高浓度有机废物时产气及产甲烷的变化特性。结果表明，气体及甲烷主要是在第二段的中温消化反应器内产生。当中温消化反应器的有机负荷VS为1.65～3.10kg/m3d时，稳态条件下的平均产气量为1.958～4.020m3/d，气体中甲烷的平均组成为65%～73%，甲烷的比产率为0.397～O.511m3/kgVS。

高温/中温两相厌氧消化工艺，用于同时处理城市污水厂污泥和其它高浓度有机废物是一个崭新的课题，特别是将高温水解产酸相反应器的温度提高到75℃、水力停留时间控制在2.5d更是一种新的尝试。本课题源于生产实际需要而开展中试规模试验研究，目的在于考察高温/中温（75℃、2．5d/37℃、10d）两相厌氧消化反应器系统，分别同时处理污水厂污泥与主要含碳水化合物的废物（马铃薯加工废物）、污泥与主要含蛋白质的废物（猪血）污泥与主要含脂类废物（灌肠加工废物）时的效能变化，为拟建实际规模高温/中温两相厌氧消化系统提供技术依据。