Wastewater Treatment Using Fibrist and Saprist Peat: A Comparative Study

Two different peat types (fibrist and saprist) were compared to examine their respective wastewater treatment capacity in peat beds under different hydraulic loadings (1.8, 1.2, 0.9, and 0.6 m³/m² d) and pollutant loadings (dependent on influent quality). The comparative study was carried out on a pilot scale using urban wastewater which had undergone preliminary treatment. The systems were observed to retain a higher quantity of suspended solids when the load was higher, regardless of the hydraulic loading and the type of peat employed. System performance with respect to BOD was similar to that observed for COD, and it was noted that the capacity to retain organic matter decreased when the hydraulic loading or pollutant loading was increased. This effect was observed in both peats but to different degrees, being lower in the case of saprist peat. The results indicate that it would be necessary to work with low hydraulic loadings in order to comply with legislative requirements on effluent. Peat beds are therefore suitable for implementation in small population centers, where the system's efficiency partly depends on the type of peat employed. In view of the system's performance with respect to suspended solids, this technology may be considered a good primary treatment, and could be usefully combined with other processes aimed at eliminating dissolved organic matter.

Key Words :

• Peat bed
• Wastewater treatment
• Fibrist peat
• Saprist peat

ACKNOWLEDGMENTS

This study was conducted at the Institute of Water Research and the Department of Civil Engineering (University of Granada), with the invaluable collaboration of Granada's provincial government.