Variability of Physiochemical properties of Pig Manure with Added Wood Shavings during Open-Air Dumping and Windrow Composting

Background: Effective composting management practice through monitoring of composting governing parameters is very crucial in ensuring the safety and effectiveness of the composting process and hence the quality of the compost.

Aims: To assess the variability of the different physiochemical properties (pH, pile temperature, mass, VS, TS and TOC) during open-air dumping and windrow composting of raw pig manure and shavings amended pig manure with wood.

Study Design: Field and laboratory experiment.

Place and Duration of Study: Waste-to-resource project site and project laboratory of the Department of Environmental Science of the University of Buea, Cameroon between February and March 2022.

Methodology: Two sets of pig manure and wood shavings were mixed in mass ratios of 100%:0% and 90%:10% and placed in four different chambers. One set was dumped in an open-air situation while the other set was left to compost for 40 days. Piles were monitored after every next day for pH, temperature, mass loss, EC, MC, TOC, TS and VS analyses.

Results: The highest composting temperature (63.4℃) was experienced in the 90:10 % while the lowest (39.4℃) was experience in the 100%. All 100% treatments had an acidic starting pH (5.04 and 5.58) while 90:10% treatments had a more basic pH (6.76 and 6.82), there was a significant difference in EC between the open-air dumped and windrow compost piles (P = 0.000). Mass significantly reduced by 64% and 75% (100% and90:10% compost respectively), 51% and 56.5% (100% and 90:10%dumping respectively). Significant difference existed in MC (P = 0.010). Both VS and TC decrease across all treatments, the highest VS and TOC were observed in all 100:0% treatments.

Conclusion: Open-air dumping and composting of pig manure with woods shavings should be promoted since it enhances physiochemical properties, but more emphasis should be on composting than on open-air dumping.