(640d) Enhanced Degradation of Fats, Oils and Greases in Domestic Wastewater Sewer Networks and Grease Interception Systems Using Peat Humic Substances

The efficacy of peat humic substances in enhancing the degradation of fats, oils and greases (FOG) was investigated under controlled laboratory conditions using bench scale well-mixed bioreactors. An experimental design was used to evaluate the effects of temperature and peat humic substance (PHS) concentration on FOG degradation in domestic wastewater for a temperature range from 10°C to 30°C and a PHS concentration range from 0 to 20 ppm (v). Factors and interactions significantly affecting the rate of FOG degradation were identified, and models to predict FOG degradation rates as a function of PHS concentration and temperature were developed. The models were used to develop a PHS dosage calculation technique for field operations. Results indicate that PHS can enhance FOG degradation rates by up to a factor of 2, and microbial cell growth rates by up to a factor of 3. Atmospheric hydrogen sulfide generation increased with high PHS concentration at the higher temperature. The rate of FOG degradation using grease interceptor material was studied at 25°C and a PHS concentration of 500 ppm (v). In these systems, PHS was observed to increase the rate of FOG degradation by up to a factor of 2, and microbial colony growth rates by up to a factor of 5. This work indicates that PHS can enhance FOG degradation rates and increase microbial growth rates in wastewater treatment systems. These results have significant implications for wastewater treatment applications.