Penurunan Logam Hg dalam Air Menggunakan Sistem Sub-Surface Flow Constructed Wetland: Studi Efektivitas

Abstract

A B S T R A C T

High amount of Mercury contamination is commonly found in traditional gold mining areas. This problem might occur due to the use of amalgamation process in traditional gold extraction process by dissolving the gold-bearing rocks with mercury (Hg). The utilization of mercury in gold mining activity has contaminated the water with Hg which might lead to serious health problems. This research was carried out by discharging the Hg-contaminated wastewater to enter a system called the Sub-Surface Flow Constructed Wetland (SSF-SW). The system employed a mixture of soil and the fibers of water hyacinth as the media on which Echinodorus palaefolius L. was planted. The wastewater containing HgCl₂ at 8.59 mg/L was flown. The flow rate and pH were set to 6.3 L/hour and 6-7 pH at room temperature. Samples were collected at 0; 3.5; 7; 10.5 hours every day. The SSF-CW system was continually run for 10.5 hours and 13.5hour batch. The result of this research showed that the efficiency of Hg removal reached 92.79%. The results showed that the SSF-CW offers a stable system to reduce the mercury levels as shown in the growth of the plant and the total Hg removal efficiency. Plants with Hg exposure have distinct patterns of chlorosis. Some leaves turning yellow and die, others start with new growth. In addition, the growth of Echinodorus palaefolius L. was also influenced by the amount of nutrients in the soil.

Keywords: Echinodorus palaefolius L., mercury, sub-surface flow constructed wetland

A B S T R A K

Pencemaran merkuri banyak ditemukan pada penambangan emas tradisional. Pada umumnya proses yang diterapkan dalam penambangan emas tradisional dalam ekstraksi emas adalah proses amalgamasi, yaitu dengan cara mencampur bijih emas dengan merkuri (Hg). Aktivitas penambangan dengan memanfaatkan Hg menyebabkan tercemarnya air dengan Hg yang dapat membahayakan kesehatan. Penelitian ini dilakukan dengan cara mengalirkan air limbah Hg ke dalam sistem Sub-Surface Flow Constructed Wetland (SSF-CW). Media yang digunakan berupa campuran tanah dan serat eceng gondok serta ditanami dengan Echinodorus palaefolius L. Penelitian dilakukan dengan mengalirkan air limbah HgCl₂ berkonsentrasi 8,59 mg/L. Percobaan menggunakan laju alir 6,3 L/jam dengan pH sekitar 6-7 pada suhu ruangan. Pengambilan sampel dilakukan pada jam ke 0; 3,5; 7 dan 10,5 pada setiap harinya. Operasi sistem SSF-CW dijalankan 10,5 jam kontinu dan 13,5 jam batch. Hasil penelitian menunjukkan efisiensi penurunan Hg sebesar 92,79%. Penelitian menunjukkan bahwa sistem SSF-CW cukup stabil. Kestabilan sistem SSF-CW dalam menurunkan kadar Hg dapat dilihat dari pertumbuhan tanaman dan total penurunan yang diperoleh. Tanaman yang terpapar Hg terlihat bercak klorosis. Beberapa daun menguning dan mati, sebagian lain tumbuh tunas baru. Pertumbuhaan Echinodorus palaefolius L. tidak lepas dari pengaruh unsur hara yang terdapat di dalam tanah.

Kata kunci: Echinodorus palaefolius L., merkuri, sub-surface flow constructed wetland