| dc.description.abstract | Emisi asap penyangraian biji kopi mengandung volatile organic compounds
(VOC), karbon monoksida (CO), dan senyawa penyebab bau yang berpotensi
menurunkan kualitas udara. Penggunaan wet scrubber sebagai unit praperlakuan
mampu menurunkan suhu gas dan menyisihkan sebagian polutan, namun belum efektif
menghilangkan senyawa gas secara optimal sehingga diperlukan unit pengolahan
lanjutan (polishing unit). Proyek ini bertujuan merancang biofilter sebagai unit pascapengolahan untuk penyisihan VOC dan senyawa penyebab bau pada emisi
penyangraian biji kopi, merealisasikan hasil perancangan dalam bentuk prototipe skala
laboratorium, serta mengevaluasi kinerja awal biofilter berdasarkan penurunan
konsentrasi VOC dan CO. Biofilter dirancang secara teoritis untuk mesin penyangrai
berkapasitas 5 kg/batch dengan debit gas 200 m³/jam, menghasilkan spesifikasi reaktor
berukuran 1,43 m × 1,43 m × 2,00 m, volume media 2,0361 m³, dan Empty Bed
Residence Time (EBRT) 37,02 detik menggunakan media hibrida sekam bakar, serbuk
gergaji, kompos (5:3:2), dan batu apung sebagai lapisan penyangga. Validasi konsep
dilakukan menggunakan prototipe skala laboratorium (drum HDPE 150 L; EBRT 7,15
detik) pada beban penyangraian 500 g dan 1.250 g. Hasil pengujian menunjukkan
bahwa biofilter mampu menurunkan konsentrasi VOC dari 0,65 ± 0,03 ppm menjadi
0,29 ± 0,04 ppm (efisiensi 55,38%) pada beban 500 g, dan dari 2,19 ± 0,01 ppm
menjadi 0,38 ± 0,02 ppm (efisiensi 82,65%) pada beban 1.250 g. Efisiensi penyisihan
CO masing-masing mencapai 62,24% dan 92,60%. Hasil ini mengonfirmasi bahwa
konfigurasi media hibrida dan strategi inokulasi activated sludge + EM4 layak secara
teknis sebagai proof of concept unit pasca-pengolahan. Meskipun demikian, kinerja
pada kapasitas desain 5 kg/batch belum dapat diklaim tercapai dan memerlukan
validasi lebih lanjut pada skala penuh dengan pengukuran parameter kinetik biologis
dan neraca massa yang komprehensif.
Coffee bean roasting exhaust emissions contain volatile organic compounds
(VOCs), carbon monoxide (CO), and odor-causing compounds that may contribute
to air pollution. Although a wet scrubber can reduce exhaust gas temperature and
remove part of the pollutants, it is generally insufficient for eliminating gaseous
contaminants effectively, making an additional polishing unit necessary. This
project aimed to design a biofilter as a post-treatment unit for removing VOCs and
odor-causing compounds from coffee roasting emissions, develop a laboratoryscale prototype based on the proposed design, and evaluate its preliminary
performance through the reduction of VOC and CO concentrations. The biofilter
was theoretically designed for a coffee roaster with a capacity of 5 kg per batch
and a gas flow rate of 200 m³/h, resulting in a reactor measuring 1.43 m × 1.43 m
× 2.00 m with a media volume of 2.0361 m³, an Empty Bed Residence Time (EBRT)
of 37.02 s, a True Bed Residence Time (TBRT) of 14.07 s, and a Surface Loading
Rate (SLR) of 98.22 m³/m²·h. The biofilter medium consisted of rice husk charcoal,
sawdust, and compost mixed at a volumetric ratio of 5:3:2, supported by a pumice
stone layer. The design was verified through the fabrication of a laboratory-scale
prototype using a 150 L HDPE drum while maintaining the proposed flow
configuration and operating principles. Performance evaluation was conducted at
roasting capacities of 500 g and 1,250 g using wet scrubber outlet gas as the
biofilter inlet. At the 500 g capacity, the biofilter reduced VOC concentration from
0.65 ± 0.03 ppm to 0.29 ± 0.04 ppm with a removal efficiency of 55.38%, while CO
concentration decreased from 9.80 ± 0.50 ppm to 3.70 ± 0.40 ppm with a removal
efficiency of 62.24%. At the 1,250 g capacity, removal efficiencies increased to
82.65% for VOC and 92.60% for CO. These results confirm that the hybrid media
configuration and activated sludge + EM4 inoculation strategy are technically
feasible as a proof of concept for a post-treatment unit. However, performance at
the full 5 kg/batch design capacity has not yet been validated and requires further
testing with comprehensive biological kinetic measurements and mass balance
analysis before implementation. | |
