Fecal Coliform and plant nutrients removal from domestic waste by soil columns

Abstract

Seven soil series ; Sattahip, Mauk Lek, Ban Bung, Chon Buri, Klaeng, Kampang Saen and Thon Buri were investigated in order to determine the efficiency of their use for domestic wastewater disposal. The soil samples were taken in two separated [columns] of 0-50 cm and 50-100 cm depth from each site. The wastewater was allowed to seep through the soil [columns] within a period of 45 days. The studies reveal that only the soils of sandy loam and loamy sand texture could allow the infiltration of the wastewater. It also indicates that the soils with higher permeability has a lower efficiency than those with lower permeability. Nevertheless, all permeable soil series could reduce the total bacteria and COD in the wastewater more than 95 and 71% respectively. However, only the Sattahip, Mauk lek and Ban Bung soil series, with 0-50 cm. depth, could maintain the aerobic condition after 45 days of wastewater treatment. This is evidenced by the transformation of NH₄-N to NO₃-N owing to their low capacity in retaining ions and filtering. Therefore, these three soil series could entirely remove the orthophosphate and fecal [coli form] after 5 and 21 day treatment respectively. In addition, these soils could also raise the pH of the waste water to a certain extent after infiltrating through them.