Abstract: The sedimentation effect, changes of viscosity and extracellular polymeric substance （EPS） concentration of kitchen biogas slurry under different irradiation doses were investigated using electron beam （EB） irradiation technology, and kitchen biogas slurry was taken as the research object. SS concentration in kitchen biogas slurry was significantly reduced through the EB coupled coagulation and low-speed centrifugation (EBCC) process. Results showed that when the irradiation absorbed dose of EB exceeded 10 kGy, the sedimentation rate could reach over 60% in 10 minutes. The viscosity and the EPS concentration could be reduced from 52.18 mPa·s to 6.57 mPa·s and 410.00 mg/L to 215.63 mg/L, respectively. Moreover, the SS concentration of the slurry rapidly decreased from 15 100 mg/L to 2 650 mg/L, resulted in an SS removal efficiency reaching up to 82.45% by using the EBCC process with the optimal dosage of coagulants (4‰ PAFC and 4‰ PAM). Additionally, from a technical and economic perspective, the operating cost of EBCC process was 7.71 yuan/m3. These findings demonstrated that the potential of EB technology has significant advantages in high-viscosity solid-liquid separation for kitchen biogas slurry.

Key words: kitchen biogas slurry, electron beam irradiation, coagulation low speed centrifugation, removal rate, extracellular polymer