Co-digestion of poultry manure with mixture of coffee, cassava and coconut wastes

Abstract EN

This study was conducted to test the effect on thermophilic and mesophilic digestion of poultry manure (PM) or treated poultry manure (TPM) by the addition of agriculture wastes (AWS) as a co-substrate under dry conditions.

PM was co-digested with a mixture of AWS consisting of coconut waste, cassava waste, and coffee grounds.

Obtained results revealed increased methane content in biogas, with decrease ammonia accumulation and volatile acids (VFA).

The highest performance occurred under mesophilic conditions, with a 63% and 41.3% increase in methane production from addition of AWS to TPM (562ml g VS-1 vs.

344 ml g VS-1 from control) and PM (406 ml g VS-1 vs.

287 ml g VS-1 from control), respectively.

Thermophilic conditions showed lower performance than mesophilic conditions.

Addition of AWS increased methane production by 150% and 69.6% from PM (323.4 ml g VS-1 vs.

129 ml g VS-1 from control), and TPM (297.6ml g VS-1 vs.

175.5 ml g VS-1 from control), respectively.

In all experiments, 100% acetate produced was degraded to methane.

Maximum ammonia accumulation was lowered to 43.7% by mixing of AWS (range 5.35-8.55 g N/kg-1 bed vs.

7.81-12.28 g N/kg-1 bed).

The pH was held at 7.3-8.8, a range suitable for methanogenesis.