Pengolahan Limbah Cair Industri Tahu Dengan Proses Biofilter Aerobik

Abstract

Study on the effect of varying initial COD concentration, hydraulic retention time (HRT) of the reactor and height of medium to % reduction of chemical oxygen demand (COD) and mixed liquor suspended solid (MLSS) from tofu wastewater was conducted in aerobic biofilter reactor by using gravel packing medium. The operation variables were the COD influent (500, 750 and 1000 mg/L), the hydraulic retention time or HRT (5, 7 and 9 hours) and the height of medium (100 and 125 cm). The results of the experiment showed that the reduction of COD was affected by hydraulic retention time (HRT), while the reduction MLSS did not affected by HRT. The percentages of COD and MLSS removal have increased as well as increasing of the height of bed, however, the percentages of COD and MLSS removal have decreased as well as the increase of the concentration of COD influent. The percentages of COD and MLSS removal were higher in 125 cm than 100 cm height of biofilter bed. five to nine hours HRT and the 500 mg/L of COD influent and 125 cm height of bed gave the best total % reduction of COD and MLSS effluent. At this condition, observation indicated that the average of COD and MLSS removal were 175,88 mg/L (61,49%) dan 77,67 mg/L (71,34%), respectively. Although 5 to 9 hours HRT and the concentration of COD influent 500 mg/l gave the best total COD and MLSS reduction, however, it was not met to environmental standard quality (SKMenLH No.Kep-51/MENLH/10/1995), especially the COD parameter (maximum COD and MLSS are 100 and 200 mg/L, respectively).

Penelitian untuk mengetahui pengaruh konsentrasi chemical oxygen demand (COD) influent, hydraulic retention time (HRT) dan tinggi unggun terhadap efisiensi penurunan COD dan mixed liquor suspended solid (MLSS) dari limbah cair industri tahu telah dilaksanakan dalam reaktor biofilter aerob dengan media kerikil. Variabel operasi penelitian adalah konsentrasi COD awal limbah (500, 750 dan 1000 mg/L), HRT (5, 7 dan 9 jam) dan tinggi unggun (100 dan 125 cm). Hasil penelitian menunjukkan, bahwa peningkatan waktu tinggal cairan (HRT) di dalam reaktor berpengaruh terhadap penurunan COD, tetapi tidak berbeda nyata terhadap penurunan MLSS. Semakin besar konsentrasi COD awal limbah, semakin kecil % penurunan COD dan MLSS dan efisiensi penurunan COD dan MLSS pada tinggi unggun 125 cm lebih tinggi dibanding pada tinggi unggun 100 cm. Penggunaan waktu tinggal (HRT) 5 – 9 jam dengan konsentrasi COD awal 500 mg/L dan tinggi unggun 125 cm memberikan hasil terbaik terhadap penurunan konsentrasi COD dan MLSS. Dari hasil percobaan, diperoleh konsentrasi rata-rata COD dan MLSS effluent terbaik untuk tinggi unggun 125 cm berturut-turut sebesar 175,88 mg/L (61,49%) dan 77,67 mg/L (71,34%). Akan tetapi bila dibandingkan dengan baku mutu effluent yang dipersyaratkan menurut SKMenLH No.Kep-51/MENLH/10/1995 tentang Baku Mutu Limbah Cair Bagi Kegiatan Industri (konsentrasi COD dan MLSS maksimum yang diperbolehkan adalah 100 mg/L dan 200 mg/L), hasil yang dicapai khususnya parameter COD belum memenuhi baku mutu.