**Author details**

by nitrifying

− .

in

[20, 32]. Authors reported that 4.5 s was required for the biodegradation of NH<sup>3</sup>

removal capacities in various biofiltration systems.

Sludge + 20% GAC Activated sludge 10.1 ‐ Chen et al., [26] Pall ring Activated sludge 4.5 5.5 Kim et al., [20]

Ceramics Soil 34.3 49.4 Kanagawa et al., [33] Coal slag Activated sludge 108.4 140.8 Present study

the inhibitory effect of high NH<sup>3</sup>

**Table 6.** Comparison of NH<sup>3</sup>

**Packing material Microorganism Critical loading (g** 

**Biofilter**

70 Nitrification and Denitrification

Compost + bark +

50% organic + 50% inorganic

Compost + 20% perlite

**Biotrickling**

peat

**m−3 h−1)**

Peat Night soil sludge 30.0 41.7 Kim et al., [31] Rock wool Night soil sludge 33.8 50.0 Kim et al., [31] Fuyolite Night soil sludge 22.1 28.3 Kim et al., [31] Ceramics Night soil sludge 23.8 38.3 Kim et al., [31] Fuyolite *Vibrio alginolyticus* 93.0 114.0 Kim et al., [31] Granulated sludge Activated sludge 5.8 20.8 Gracian et al., [36]

Activated sludge 19.0 22.6 Choi et al., [37]

Activated sludge 11.8 14.0 Choi et al., [36]

Activated sludge 12.0 ‐ Chen et al., [26]

**Max. elimination capacity (g m−3 h−1)** **References**

inhibitory effects of high NH<sup>3</sup>

**4. Conclusions**

for the NH<sup>3</sup>

bacteria [33]. In this study, the system was operated at EBRT of 8 s. This showed that the decrease of removal may be due to the mass transfer limitation from gas to liquid phases or

At lower loading rates (i.e., 78 to 86 g m−3 h−1), the main metabolite in the system was NO<sup>3</sup>

This confirmed that the complete removal obtained was mainly contributed by the activities of autotrophic AOB and not by the physical absorption or adsorption. In fact, the organic and gaseous nitrogen was only around 5% under these conditions. The percentages of nitrite and ammonium increased directly proportional to the loading. At the highest loading rate, ammonium became the dominant by‐product which accounted for more than 50%, while the removal efficiency was higher than 80%. Although a very high removal efficiency of NH<sup>3</sup>

the system was attained, a complete nitrification in the biofilm was never achieved due to the

The results of this study suggest that the biotrickling filter is a viable and effective method

removal. A comparatively short start‐up of the system was accomplished within

concentration.

concentration on the oxidation activity of AOB.

Yiu Fai Tsang1,2\*, Ya‐nan Wang<sup>3</sup> , Huawei Wang4,5, Yi Yang1 , Yuanhui Zhang<sup>6</sup> and Hong Chua<sup>7</sup>

\*Address all correspondence to: tsangyf@eduhk.hk

1 Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, New Territories, Hong Kong

2 Guizhou Academy of Sciences, Guiyang City, Guizhou Province, PR China

3 College of Environmental Science and Engineering, Tongji University, Shanghai, PR China

4 Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, PR China

5 College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, PR China

6 Department of Agricultural and Biological Engineering, University of Illinois at Urbana‐ Champaign, USA

7 Faculty of Science and Technology, Technological and Higher Education Institute of Hong Kong, Tsing Yi, Hong Kong

## **References**


[13] Anet B, Couriol C, Lendormi T, Amrane A, Le Cloirec P, Cogny G, Fillieres R. Cha‐ racterization and selection of packing materials for biofiltration of rendering odourous emissions. Water Air and Soil Pollution. 224;7:1‐13. DOI: 10.1007/s11270‐013‐1622‐1.

**References**

72 Nitrification and Denitrification

Review. 2012;18:135‐138.

cej.2007.04.015.

6.12.032.

10.1016/S0960‐8524(00)00074‐2.

[1] Bibbiani C, Russo C. Odour emission from intensive livestock production system: Approaches for emission abatement and evaluation of their effectiveness. Large Animal

[2] Gabriel D, Maestre JP, Martin L, Gamisans X, Lafuente J. Characterisation and perfor‐ mance of coconut fibre as packing material in the removal of ammonia in gas‐ phase biofil‐ ters. Biosystems Engineering. 2007;97:481‐490. DOI: 10.1016/j. biosystemseng.2007.03.038.

[3] Lin YH, Chen YP, Ho KL, Lee TY, Tseng CP. Large‐scale modular biofiltration system for effective odor removal in a composting facility. Journal of Environmental Science and Health Part A‐Toxic/Hazardous Substances and Environmental Engineering.

[4] Posmanik R, Gross A, Nejidat A. Effect of high ammonia loads emitted from poultry‐ manure digestion on nitrification activity and nitrifier‐community structure in a compost biofilter. Ecological Engineering. 2014;62:140‐147. DOI: 10.1016/j.ecoleng.2013.10.033. [5] Taghipour H, Shahmansoury MR, Bina B, Movahdian H. Operational parameters in biofiltration of ammonia‐contaminated air streams using compost‐pieces of hard plastics filter media. Chemical Engineering Journal. 2008;137:198‐204. DOI: 10.1016/j.

[6] Cohen Y Biofiltration – The treatment of fluids by microorganisms immobilized into the filter bedding materials: A review. Bioresource Technology. 2001;77:257‐274. DOI:

[7] Kennes C, Rene ER, Veiga MC. Bioprocesses for air pollution control. Journal of Chemical

[8] Mudliar S, Giri B, Padoley K, Satpute D, Dixit R, Bhatt P, Pandey R, Juwarkar A, Vaidya A. Bioreactors for treatment of VOCs and odours–A review. Journal of Environmental

[9] Pagans E, Font X, Sanchez A. Biofiltration for ammonia removal from composting exhaust gases. Chemical Engineering Journal. 2005;113:105‐110. DOI: 10.1016/j.cej.2005.03.004.

[10] Tsang YF, Chua H, Sin SN, Chan SY. Treatment of odorous volatile fatty acids using a biotrickling filter. Bioresource Technology. 2008;99:589‐595. DOI: 10.1016/j. biortech.200

[11] Dorado A, Lafuente F, Gabriel D, Gamisans X. A comparative study based on physical characteristics of suitable packing materials in biofiltration. Environmental Technology.

[12] Pagans E, Font X, Sanchez A. Adsorption, absorption, and biological degradation of ammonia in different biofilter organic media. Biotechnology and Bioengineering. 2007;‐

Technology and Biotechnology. 2009;84:1419‐1436. DOI: 10.1002/jctb.2216.

Management. 2010;91:1039‐1054. DOI: 10.1016/j.jenvman.2010.01.006.

2010;31:193‐204. DOI: 10.1080/09593330903426687.

97:515‐525. DOI: 10.1002/bit.21246.

2013;48:1420‐1430. DOI: 10.1080/10934529.2013.781898.

