Composting Short Paper Fiber With Broiler Litter And Additives

Abstract

Short paper fiber (SPF), a by-product of the paper mill industry, was cocomposted with broiler litter (BL) to determine the mixture's kinetic parameters as functions of initial C/N ratio and mixing ratio. An equation describing throughput capacity of composting facilities as a function of kinetic parameters was used to optimize mixing ratio (MiR) for maximization of composting short paper fiber. MiR [SPF/(SPF+BL), kg/kg(dry basis)] used were 0.8 to 0.4 in five series of pilot-scale studies. Test conditions were C/N of 15 to 49, pH of 7.0 to 8.0, composting temperature of 60°C, moisture of 50-55% w.b. and remixing 2 times per week. Composting trials lasted 2 weeks. Ammonia loss, O₂, CO₂, compost temperatures and dry solids loss were measured. Maximum decomposition, based on dry solids loss, occurred in the [C/N] range of 30-38. Maximum decomposition was 0.11 kg.kg⁻¹.day⁻¹ based on the first order kinetic model with β = 0.73 (MiR = 0.75). Evaluated β remained above the ash levels of the mixes for only MiR >0.25. Optimum mixing ratio was 0.7 (7 part SPF and 3 part BL) for maximization of short paper fiber composting. This occurred for a C/N of ≈35.