Comparison of biological H2S removal characteristics between a composite packing material with and without functional microorganisms

Rencheng Zhu,Xiaofeng Bao,Shunyi Li,Éric Dumont

doi:10.1038/srep42241

Abstract

The performances of two identical biofilters, filled with a new composite packing material (named CM-5) embedded with functional microorganisms or sterilized CM-5 without microorganisms, were investigated for H2S treatment. Running parameters in terms of microbial counts, pressure drops, and inlet and outlet H2S concentrations were measured. The results show that the microbial count of the CM-5 was approximately ×105 CFU/g before being filled into the biofilter, while that of the sterilized CM-5 was negligible. The functional microorganisms embedded in CM-5 adapted to the environment containing H2S quickly. In most cases, pressure drops of the CM-5 biofilter were slightly higher than those of the sterilized CM-5 biofilter when the gas flow rate was 0.6–2.5 m3/h. The maximum elimination capacity (EC) of the CM-5 biofilter in treating H2S could reach up to 65 g/(m3·h) when the loading rate (LR) was approximately 80 g/(m3·h). If the LR was much higher, the measured EC showed a slight downward trend. The experimental ECs of biofilters were fitted by two typical dynamic models: the Michaelis-Menten model and the Haldane model. Compared with the Michaelis-Menten model, the Haldane model fit the experimental ECs better for the two biofilters because of the presence of the substrate inhibition behaviour.

Highlights

The performances of two identical biofilters, filled with a new composite packing material embedded with functional microorganisms or sterilized CM-5 without microorganisms, were investigated for H2S treatment
After running 10 days, the quantity of microorganisms on CM-5 reached ×106 CFU/g, indicating that the functional microbial communities adapted to the environment containing H2S and propagated rapidly
One reason was that there were large amounts of functional microorganisms on CM-5, while those of sterilized CM-5 were mainly from waste gas and spraying water. Another speculation might be that the bioavailability of nutrients contained in sterilized CM-5 decreased through the sterilization process

Summary

Introduction

The performances of two identical biofilters, filled with a new composite packing material (named CM-5) embedded with functional microorganisms or sterilized CM-5 without microorganisms, were investigated for H2S treatment. A plethora of research on different types of packing materials (organic, inorganic and synthetic materials) has been conducted for biofilters[15]. Wood bark, have advantages in terms of nutrient sources and native microorganisms, while they tend to compact after running a course of time, which will result in increasing pressure drops and cause inhomogeneous air flow distributions[16]. Inorganic materials, such as lava rock, metal oxides, ceramsite and pall ring, can be used. Only few papers have evaluated the performance of packing material embedded functional microorganisms in a biofilter[12,19]

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