Journal of Experimental Agriculture International

Aim: The aim of the study was to assess the effects of anaerobic co-digestion of maize cob and poultry manure on biogas yields and their digestate characteristics.

Place and Duration of Study: Department of Forestry Technology, Federal College of Forestry, Jos between March and April, 2018.

Methodology: Slurries of five co-substrate treatment ratios viz 0:1(T₁), 1:3(T₂), 1:1(T₃), 3:1(T₄) and 1:0(T₅) of these wastes (in three replicates) were separately fed to 13.6L locally made batch-digesters. The anaerobic reactors were monitored for a 56 day retention period. Weekly biogas yields and some digestate characteristics were measured by standard methods.

Results: The cumulative biogas yields was in the order of T₃(2481.3 mL/kg) >T_I(2197.9 mL/kg) > T₄(2163.0 mL/kg) > T₂(2116.3 mL/kg) >T₅(1713.2 mL/kg), in favor of the mixed substrates. While the percentage C:N reductions ranged from (12.94% - 81.80%), with T₅ and T₁ recording the highest and lowest values respectively. The chemical oxygen demand removal was in the order of T₃(80.70%) > T₄(58.00%) >T₅(46.81%) >T₁(34.15%) >T₂(13.16%). The anaerobic digestion (AD) effected reductions in Mg, C, Ca, P, Mn, Zn, Fe, Pb and increase in Cu contents of the digestates across treatments. While the K contents increased in T₂(36.72%), T₃(229.79%) and T₄(220.51%); %N in T₃(9.94%), T₄(113.19%) and T₅(291.84%) and Na increased only in T₄(4.55%). The Cu contents indicated % increase in the order of T₅(487.5%) >T₃(270.97%) >T₂(268.10%) >T₄(43.66%) >T₁(35.82%).

Conclusion: The anaerobic co-digestion of these organic wastes had unlocked the alternative energy potentials, enhanced the bioremediation tendency, while promoting sustainable public health and environmental management.