Feasibility study on odor reduction in the composting process of municipal organic waste by adding odor-reducing compounds

Odor emission in compost production facilities is a significant environmental and health challenge. This study investigates the extent of odor reduction using three additives: copper sulfate, ferric chloride, and wastewater treatment sludge containing ferric chloride.

In this study, the effects of additives were examined in aerated compost reactors, including a control group and various concentrations of the additives. The composting process for each treatment was conducted under identical and optimized conditions in terms of biological processes. Gas sampling was performed on days 5, 10, 15, 20, 25, and 30 of the composting process using a portable Phocheck device and an impinger. Ethical considerations were taken into account at all stages of the study implementation.

By adding 7.5grams of ferric chloride per kilogram of waste, the odor number decreased from 22.28 in the control treatment to 11.07 OU/m³ (a reduction of 67%). The reduction in odor caused by H2S in the treatment with a combination of 5.7grams of ferric chloride and 25 grams of sewage sludge per kilogram of waste was 41% and 45% higher than in the other treatments, respectively. Additionally, these additives altered the intensity classification from strong odor levels in controls to mild or very mild classifications in test treatments.

The addition of optimal amounts of these additives effectively reduced odor emissions without adversely affecting the composting mechanism. The results indicated that while copper sulfate was effective in reducing odor emissions, its impact was less significant compared to ferric chloride and wastewater sludge.