传统的活性污泥工艺中加入废弃轮胎颗粒作为生物膜载体形成的复合式生物膜反应器，在颗粒浓度为40g/L时，稳定运行条件下在轮胎颗粒表面可形成约50mg/g的生物膜量，即在传统曝气池的2000～3000mg/L悬浮生长污泥的基础上，可增加2000mg/L的附着生物膜量。此时生物膜的厚度为255Lm，其活性以比耗氧速率（SOUR）表示为40～70mg/g·h。

为了有效地去除垃圾渗滤液中高浓度的NH+4-2N而避免传统吹脱法造成吹脱塔内的碳酸盐结垢问题，探讨了采用化学药剂诸如MgCl2·6H2O和Na2HPO4·12H2O或MgO和H3PO4使NH+42N生成磷酸铵镁的化学沉淀去除法。小试研究结果表明，当垃圾渗滤液中投加MgCl2·6H2O和Na2HPO4·12H2O而使Mg2+：NH+4：PO3-4的比例为1:1:1时，在最佳pH为815～910的条件下原垃圾液中的NH+42N可由5618mg/L降低到65mg/L；另外2种药剂MgO和85%的H3PO4不如前者有效，在同等条件下只能使NH+42N由5404mg/L降低到1688mg/L.

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.

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

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 +