Pemanfaatan Granul FABA dan FABA-Pupuk Kandang Kambing, serta Tanaman Canna x generalis untuk Remediasi Air Asam Tambang

Abstract

Pertambangan berperan penting bagi ekonomi Indonesia. Kegiatan pertambangan dapat menghasilkan limbah yang dapat menimbulkan dampak lingkungan, sepert Air Asam Tambang (AAT). Pengelolaan AAT umumnya dilakukan dengan menambahkan bahan alkali seperti kapur atau natrium hidroksida untuk meningkatkan pH dan mengendapkan logam. Metode tersebut efektif, tetapi memerlukan biaya yang tinggi dan kurang sesuai untuk pengelolaan jangka panjang di wilayah pasca-tambang. Kondisi tersebut mendorong berkembangnya sistem pengelolaan berbasis limbah atau material alami sebagai alternatif praktis. Dalam konteks tersebut, fly ash dan bottom ash (FABA) dipilih sebagai bahan utama karena memiliki sifat basa yang telah terbukti efektif dalam mengendalikan AAT melalui kandungan mineral seperti CaO, MgO, dan Al2O3 yang mampu menetralkan keasaman. Selain itu, pupuk kandang kambing digunakan sebagai bahan tambahan dalam pembentukan granul karena telah terbukti mampu menetralkan keasaman dan perannya dalam menyediakan unsur hara mikro serta menciptakan kondisi mikrobiologis yang mendukung pertumbuhan tanaman fitoremediator. Kombinasi FABA dan pupuk kandang kambing diharapkan menghasilkan granul basa organik yang tidak hanya berfungsi sebagai agen penetral AAT, tetapi juga mendukung sistem remediasi berkelanjutan melalui pendekatan fitoremediasi. Meskipun potensi FABA dan pupuk kandang kambing sebagai bahan remediasi AAT telah banyak dilaporkan, pengaruh variasi komposisi, posisi, dan volume granul, serta integrasinya dengan tanaman fitoremediator, masih perlu dikaji lebih lanjut. Oleh karena itu, penelitian ini bertujuan untuk menguji efektivitas granul FABA, campuran FABA–pupuk kandang kambing, serta tanaman Canna x generalis dalam remediasi AAT. Lebih spesifik, penelitian ini menganalisis pengaruh komposisi, posisi, dan volume granul terhadap remediasi AAT, mengidentifikasi kombinasi perlakuan terbaik dari ketiganya, menganalisis karakteristik morfologi dan pengaruh tanaman dalam meremediasi AAT, serta menganalisis kombinasi granul dan tanaman dalam mempengaruhi pH AAT dan pertumbuhan tanaman. Penelitian ini dilaksanakan melalui tahapan terstruktur yang dimulai dari analisis pendahuluan, pembuatan dan pengujian efektivitas granul FABA dan FABA-pupuk kandang kambing, penerapan kombinasi granul dan tanaman Canna x generalis dalam sistem fitoremediasi, hingga analisis perbandingan biaya pengolahan AAT antara granul dan kapur. Setiap tahap dirancang untuk mengevaluasi kinerja teknis penetralan AAT serta efisiensi pengolahan, yang selanjutnya dianalisis secara statistik dan ekonomi. Hasil pengujian menunjukkan granul tanpa pupuk kandang kambing pada konsentrasi 50% dalam posisi melayang di bawah permukaan air meningkatkan pH AAT dari 2,45 menjadi 9,17 dalam tiga jam dan menghilangkan 88,7% besi dan 66,5% mangan. Analisis mineral menunjukkan bahwa peningkatan pH berasal dari pelarutan mineral kaya kalsium yang membentuk mineral baru seperti kalsit dan gipsum. Granul yang mengandung pupuk kandang kambing bekerja lebih lambat tetapi memberikan hasil keseluruhan yang serupa. Hasil pengujian granul FABA-pupuk kandang kambing menunjukkan bahwa pertumbuhan tanaman tidak berbeda secara signifikan antara perlakuan, dan semua tanaman tetap hidup. Tanaman yang ditanam pada media inert saja juga mampu meningkatkan pH AAT dari 2,45 menjadi 6,74 dalam dua hari, dan pH tetap stabil sekitar 7,5 selama sisa uji 12 hari. Secara keseluruhan, granul FABA terbukti efektif untuk menetralkan AAT dengan cepat, sementara Canna x generalis menunjukkan potensi sebagai perlakuan lanjutan yang bekerja secara bertahap dan dapat memperbaiki penampilan area perlakuan AAT. Menggabungkan kedua pendekatan ini menawarkan opsi praktis dan lebih berkelanjutan untuk pengelolaan AAT. Dari hasil komparasi pengolahan AAT antara granul FABA dan kapur didapat bahwa granul FABA dapat menekan biaya hingga 99%.

Mining plays an important role in Indonesia’s economic development; however, mining activities also generate waste that can cause serious environmental impacts, one of which is acid mine drainage (AMD). AMD is commonly managed by the addition of alkaline materials such as lime or sodium hydroxide to increase pH and precipitate dissolved metals. Although this approach is effective, it is associated with high operational costs and is less suitable for long-term management, particularly in extensive post-mining areas. These limitations have encouraged the development of AMD management strategies based on waste-derived or natural materials as more practical and sustainable alternatives. In this context, fly ash and bottom ash (FABA) were selected as the primary materials because of their alkaline properties, which have been proven effective in controlling AMD through mineral components such as CaO, MgO, and Al2O3 that are capable of neutralizing acidity. In addition, goat manure was used as an additive in granule formation because it has been reported to contribute to acidity neutralization and plays an important role in supplying micronutrients and creating favorable microbiological conditions that support the growth of phytoremediator plants. The combination of FABA and goat manure is therefore expected to produce organic alkaline granules that not only function as AMD-neutralizing agents but also support sustainable remediation systems through a phytoremediation-based approach. Although the potential of FABA and goat manure as AMD remediation materials has been widely reported, the effects of variations in granule composition, placement, and volume, as well as their integration with phytoremediator plants, remain insufficiently explored. Therefore, this study aimed to evaluate the effectiveness of FABA granules, FABA–goat manure composite granules, and a phytoremediator plant (Canna x generalis) in AMD remediation. Specifically, this research investigated the effects of granule composition, placement, and volume on AMD remediation performance, identified the optimal treatment combination, examined granule characteristics and plant-related effects on AMD remediation, and evaluated the combined influence of granules and plants on AMD pH and plant growth. This research was conducted through structured stages starting from preliminary analysis, the preparation and testing of FABA granules and FABA-goat manure, the application of a combination of FABA-goat manure granules and Canna x generalis plants in a phytoremediation system, and a comparative analysis of the AMD treatment costs between granules and lime. Each stage was designed to evaluate the technical performance of AMD neutralization and treatment efficiency, which were then analyzed statistically and economically. The results showed that the application of FABA granules without goat manure performed the best result in increasing AMD pH within short time. At a 50% concentration in a submerged position, these granules increased the pH of the AMD from 2.45 to 9.17 within three hours and removed 88.7% of the iron and 66.5% of the manganese from the AMD. Mineral analysis indicated that the increase in pH resulted from the dissolution of calcium-rich minerals, forming new minerals such as calcite and gypsum. The granules containing goat manure worked more slowly but produced similar overall results. Plant growth did not differ significantly between treatments, and all plants survived. Plants grown in an inert medium alone also increased the pH of the AMD from 2.45 to 6.74 in two days, and the pH remained stable at around 7.5 for the remainder of the 12-day test. Overall, FABA granules proved effective in rapidly neutralizing AMD, while Canna x generalis showed potential as a follow-up treatment that works gradually and can improve the appearance of AMD treatment areas. Combining these two approaches offers a practical and more sustainable option for AMD management. A comparison of AMD treatment using FABA granules and lime revealed that FABA granules can reduce costs by up to 99%.