Micro-Particle ZVI Inhibition Threshold in Cassava Pulp Bio-Methanation.

Htay Aung Pyae; Win Win Aye; Chatpet Yossapol; Somchai Dararatana

One setback of mono-digestion for biogas production is low methane (CH4) content, the core energy calorific value. Catalyst and nutrient supplementation are the option to improve biogas both in quantity and quality by reducing carbon dioxide (CO2) back to methane (CH4). Using CSTRs, this study attempted to enhance bio-methane from cassava pulp and its wastewater by readily available reducing agent, Zero Valent Iron, Fe0 (ZVI). M100 iron in micromillimeter size particle was verified and characterized by synchrotron lights (XPS) whether it is in state of valency 0 for optimum reactional kinetic. Introduced ZVI in 0-0.25-0.5-1-2 g/L dosage, it was discovered that 1 g/L ZVI microparticle concentration resulted maximized SCOD removal (up to 95%) generating biogas for 900 ml/day/OLR with highest methane content (85%). Although the presence of ZVI is stimulatory, inhibition started when iron concentration exceeds 1 g/L ending digestion failure by iron toxicity after 5 days along comparative study for 30 days HRT. Meanwhile, the performance of CSTRs in remaining doses functioned stably among which ZVI microparticle in 1 g/L supplemented CSTR processed in ideal bio-methanation. This study inspires the possibility of enriching more bio-methane by cutting hefty cost and chemicals consumption in subsequent gas upgrading processes.

BIOGAS production; BIOGAS; CASSAVA; METHANATION; IRON; CARBON dioxide; DRUG dosage; REDUCING agents

EnvironmentAsia, 2019, Vol 12, p64

1906-1714

Academic Journal

10.14456/ea.2019.64