Impact of pH and loading rate on hydrogen sulphide removal efficiency in a biotrickling filter

Hydrogen sulphide (H2S) removal is a critical aspect of waste gas treatment, particularly in industries, municipalities, and agriculture. This study investigates the impact of pH and loading rate on the efficiency of hydrogen sulphide removal in biotrickling filters. Biological methods, acknowledged as Best Available Techniques (BAT), are gaining prominence due to their advantages over classical physicochemical methods. The research aims to elucidate the influence of pH levels and loading rates on the performance of biotrickling filters in mitigating hydrogen sulphide emissions. The tests were conducted at constant pH values of 1, 2, 3 and 4, which were automatically maintained using a pump dispensing NaOH solution. The H2S concentrations at the inlet to the column were selected from a range of 60 – 300 ppm. During the study, the proportions of various groups of microorganisms (mesophilic bacteria for environmental application, potentially pathogenic mesophilic bacteria and microscopic fungi), the loading rate (LR), elimination capacity (EC), and removal efficiency (RE) were determined at pilot-scale level, with gas volume flow rates of 40 L*min-1 During the series of measurements, a maximum elimination capacity of the biotrickling filter of 224 g H2S/(m3ˑh), with nearly 100 % H2S removal, was achieved.