Effect of Organic Loading on Hydrogen in A ...

This experiment used a continuous stirred tank reactor (CSTR) with brown sugar water as the fermentation substrate, and sewage sludge as the initiation of reaction. Hydrogen production reached a stable level under conditions of an intake of pH 7.0+0.1, an oxidation-reduction potential (ORP) of -420mV, a temperature of (35 ± 1) ℃ and a hydraulic retention time (HRT) of 6 hours. (Hydrogen was the main component from the ethanol-type fermentation). We were able to focus on the impact of changing the organic load on Hydrogen production by keeping all other parameters consistent. At the same time, the microorganisms were allowed to maintain high activity by regulating the pH level. Results showed that when the organic load increased from 12 kg/m³-d to 32 kg/m³-d, the biogas and hydrogen production rates continuously increased. When the organic load was 32 kg/m³-d ,it reached a maximum production rate of 18.6L/d and a hydrogen production rate of 6.4L/d. Compared with the initial 12kg/m ³-d , gas production improved by 89% and 87%,respectively. During system operation, lowering the intake pH to 5.85 resulted in the inhibition of microbial activity of anaerobic fermentation, resulting in a decline of rate of hydrogen production and the ORP increased to-328mV. Under these conditions, the reactor could maintain a high hydrogen production rate of ethanol-type fermentation by adding a certain amount of NaOH in the reactor to regulate the pH level.