Adsorpsi dan Fitoremediasi Chrom dari Limbah Cair Laboratorium Menggunakan Sub Surface Flow Constructed Wetland (SSF-CW)

TITIK INDRAWATI, Dr. Ir.Sarto, M.Sc.,IPU; Ir. Agus Prasetya, M.Eng.Sc., Ph.D.

2021 | Tesis | MAGISTER TEKNIK KIMIA

Air limbah laboratorium yang mengandung logam berat seperti Chrom harus diolah terlebih dahulu sebelum dibuang ke perairan karena bersifat racun. Subsurface Flow Constructed Wetland (SSF-CW) adalah teknologi pengolahan air limbah alternatif yang menjanjikan yang dibangun dan dirancang berdasarkan keterlibatan tanaman air, tanah atau media lain dan mikroba terkait dalam penghilangan polutan. Tujuan dari penelitian ini adalah untuk mempelajari kemampuan tanaman akar wangi (Vetiveria Zizanoides L) dalam menurunkan kadar Chrom, mempelajari pengaruh bobot media fly ash dalam system SSF-CW serta mempelajari kinetika laju penurunan kadar Chrom dalam limbah cair. Percobaan dilakukan pada 4 (empat) model reaktor Sub Surface Flow Constructed Wetland (SSF-CW) yang berbeda, dengan ukuran 110cm (panjang) x 60cm (lebar) x 80cm (tinggi). Semua reaktor diisi dengan kerikil. Reaktor RI diisi kerikil dan fly ash saja, reaktor RIV diisi kerikil dan akar wangi saja, tanpa fly ash; sedangkan reactor RII dan RIII diisi fly ash, kerikil dan akar wangi dengan perbandingan massa fly ash dan kerikil (25:2) dan (25:1). Limbah Cair yang digunakan adalah limbah sintetik yang mengandung 14,6120 mg/L sebanyak 50 liter untuk setiap reaktor. Chrom dituangkan ke dalam reaktor dan disirkulasikan kembali secara kontinyu selama 15 hari. Sampel larutan diambil dari masing-masing reaktor pada hari ke 0; 0,2; 1; 3; 6; 9; 12 dan 15, untuk analisis Chrom. Akumulasi Chrom dalam fly ash dan tanaman dianalisis pada hari ke-15. Kinetika laju penurunan Chrom disimulasikan dengan metode Sum Square of Error (SSE) menggunakan persamaan orde 1 dan orde 2. Hasil penelitian menunjukan bahwa secara keseluruhan penyisihan Chrom dari air limbah di RI, RII, RIII dan RIV berturut-turut adalah 80,94 persen, 93,25persen, 85,77persen dan 75,74 persen. Selama penelitian terdapat perkembangan tanaman akar wangi yaitu adanya tunas baru dan peningkatan bobot tanaman. Meskipun demikian kemampuan akar wangi dalam menurunkan kadar Chrom pada RIV lebih rendah dibanding dengan proses adsorpsi di RI. Sedangkan efek bobot fly ash yang dilakukan pada percobaan di RII dan RIII menunjukan bahwa reaktor dengan bobot fly ash lebih banyak, mampu menyisihkan Chrom dengan efisiensi yang lebih tinggi. Untuk menentukan kinetika penurunan kadar Chrom digunakan nilai SSE terkecil dari perhitungan orde 1dan orde sedangkan nilai k menunjukan laju penurunan kadar Chrom. Nilai SSE untuk reaktor RI,RII,RIII dan RIV adalah 7,2810; 0,0435; 3,2084 dan 12,9134 dengan nilai k sebesar 2,4121; 5,5132; 3,4477 dan 0,1387. Dapat disimpulkan bahwa kemampuan tanaman akar wangi dalam menurunkan kadar Chrom lebih rendah dibanding proses adsorpsi yaitu 75,74persen. Kombinasi adsorpsi oleh fly ash dan fitoremediasi pada RII terbukti paling efektif dalam penyisihan Chrom dari air limbah dengan efisiensi sebesar 93,25persen selama 15 hari. Model kinetika laju penurunan kadar Chrom mengikuti model kinetika orde 1 untuk reaktor RI, RII dan RIV sedangkan pada RIII mengikuti model persamaan orde 2 dengan nilai k sebesar 2,4121; 5,5132; 3,4477 dan 0,1387. Keywords: Penyisihan Chrom, Adsorpsi, Fitoremediasi, Sub Surface flow constructed wetland

Wastewater is the residue from industrial processes, household, laboratory, or office that have experienced quality degradation due to the presence of hazardous materials. Wastewater containing heavy metals such as chromium must be treated before being discharged into the water body because of its toxicity. Subsurface Flow Constructed Wetlands (SSF-CW) is a promising alternative wastewater treatment technology that is built and designed based on to involvement of aquatic plants, soil or other media and microbes, in pollutants removal. It is a simple and easy to control technology for treating heavy metal wich contained wastewater. The aims of this research were to study the ability of vetiver (Vetiveria Zizanoides L) to reduce Chrom levels, to study the effect of fly ash media weight in the SSF-CW system and to study the kinetics of the rate of Chrom reduction in wastewater. The experiment was carried out in four (4) different reactor models, having size of 100 cm (length) x 60 cm (wide) x 80 cm (height). One reactor was filled with gravel and FA, without akar wangi (R-I), while other one was filled with gravel and akar wangi, without FA (R-IV). The other two reactors were filled with gravel, CFA and akar wangi with the mass ratio of FA/Gravel of (2: 25) and (1: 25), denoted as R-II and R-III, respectively. Fifty (50) L of synthetic wastewater containing 14,612 ppm of chromium was filled into the reactors and continuously re-circulated for 15 days. Chromium accumulation in FA and plants was analysed at days 15. The kinetics of the Chrom degradation rate was simulated by the Sum Square of Error (SSE) method using equations of order 1 and order 2. The results showed that the overall chromium removal from wastewater in RI, RII, RIII and RIV were 80.94percent, 93.25percent, 85.77percent and 75.74percent, Wastewater is the residue from industrial processes, household, laboratory, or office that have experienced quality degradation due to the presence of hazardous materials. Wastewater containing heavy metals such as chromium must be treated before being discharged into the water body because of its toxicity. Subsurface Flow Constructed Wetlands (SSF-CW) is a promising alternative wastewater treatment technology that is built and designed based on to involvement of aquatic plants, soil or other media and microbes, in pollutants removal. It is a simple and easy to control technology for treating heavy metals contained wastewater. The aims of this research were to study the ability of vetiver (Vetiveria Zizanoides L) to reduce Chrom levels, to study the effect of fly ash media weight in the SSF-CW system and to study the kinetics of the rate of Chrom reduction in wastewater. The experiment was carried out in four (4) different reactor respectively. The ability of vetiver in reducing Chrom levels in RIV is lower than the adsorption process in RI. While the effect of fly ash weight carried out in experiments in RII and RIII showed that the reactor with more fly ash weight resulted in a higher chromium removal efficiency. The kinetics of adsorption and phytoremediation in SSF-CW using smaller SEE or higher k value for equation of order 1 and order 2. The result shows that SSE values for the RI, RII, RIII and RIV reactors are 7,2810; 0.0435; 3.2084 and 12.9134 with a k value of 2.4121; 5.5132; 3.4477 and 0.1387. It can be concluded that the ability of vetiver plants to removal Chromium is lower than the adsorption process, which is 75.74percent. The combination of adsorption by fly ash and phytoremediation in RII proved to be the most effective in removing chromium from wastewater with an efficiency of 93.25percent for 15 days. The kinetic model removal of Chrom followed the first-order kinetic model for the RI, RII and RIV reactors, while the RIII model followed the second-order equation model with a k value of 2.4121; 5.5132; 3.4477 and 0.1387. Keywords: Chromium removal, Adsorption, Phytoremidiation, Coal Fly Ash (CFA), akar Wangi (Vetiveira Zizanoides L), Sub Surface Flow Constructed

Kata Kunci : Penyisihan Chrom, Adsorpsi, Fitoremediasi, Sub Surface Contructed Wetland