TREATMENT OF SLAUGHTER HOUSE WASTEWATER UTILIZING COGON GRASS (Imperata cylindrica) IN A SUBSURFACE FLOW SYSTEM CONSTRUCTED WETLAND IN ZAMBOANGA CITY, PHILIPPINES

Natural treatment systems are gaining a preference for wastewater treatment as an ecosystem-based adaptation to climate change. This study investigated the performance of a laboratory scale horizontal subsurface flow constructed wetland (SSFCW) planted with cogon grass (Imperata cylindrica) in reducing the pollutant concentration of slaughterhouse wastewater in Zamboanga City, Philippines. Results showed that the mean efficiency of BOD5 removal at seven (7) and 14 days detention time were 94.49 percent and 89.31 percent, respectively; while the average TSS removal efficiency was 97.8 percent and 99.9 percent, respectively. Statistical analysis of the BOD5 removal efficiency revealed that there is a significant difference; which means that higher BOD5 removal is achieved at seven (7) days detention time as compared to 14 days detention time. Analysis of the TSS removal efficiencies likewise revealed a significant difference, proving that longer detention time results in higher suspended solids removal. Therefore, horizontal SSFCW planted with cogon grass can be used to treat slaughterhouse wastewater at seven (7) days detention time. It is recommended that pilot study on horizontal SSFCW be conducted as well as an investigation of its performance using other wastewater sources, different parameters, and other endemic hydrophytic grasses, and to consider meteorological and climatological factors.