Perancangan Desain Otomatisasi Unit Netralisasi dan Koagulasi pada Proses Pengolahan Air Asam Tambang.

Abstract

Pertambangan batubara metode tambang terbuka berpotensi menghasilkan Air Asam Tambang (AAT) dengan pH rendah, TSS tinggi, dan kandungan logam berat, sehingga perlu diolah sebelum dibuang ke lingkungan. Penelitian ini merancang unit netralisasi dan koagulasi dengan sistem otomatisasi untuk pengolahan AAT di PT Bukit Asam Tbk. Penerapan sistem otomatisasi dipilih karena mampu meminimalkan kesalahan penambahan bahan kimia, menjaga kestabilan kualitas air olahan, serta meningkatkan efisiensi operasional dibandingkan sistem manual. Data AAT di KPL BB-07 menunjukkan pH 3,255, TSS 71 mg/L, Fe 9,1170 mg/L, dan Mn 15,7809 mg/L, melebihi baku mutu lingkungan. Dosis optimum bahan kimia ditentukan berdasarkan variasi debit harian, meliputi larutan kapur 1%, NaOH 25%, tawas 1%, dan kuriflock 1%. Unit netralisasi (235,7 m³) dan unit koagulasi (137,4 m³) masing-masing dilengkapi agitator serta sensor pH/TSS terintegrasi ESP32. Sistem memungkinkan pemantauan real-time melalui LCD dan aplikasi berbasis internet. Desain ini diharapkan meningkatkan efisiensi pengolahan dan memastikan kualitas air olahan memenuhi baku mutu secara konsisten.

Open-pit coal mining has the potential to generate Acid Mine Drainage (AMD) with low pH, high TSS, and elevated concentrations of heavy metals, which must be treated before being discharged into the environment. This study designs a neutralization and coagulation unit with an automation system for AMD treatment at PT Bukit Asam Tbk. The application of automation is selected because it minimizes dosing errors, maintains the stability of treated water quality, and improves operational efficiency compared to manual systems. AMD data from KPL BB-07 shows pH 3.255, TSS 71 mg/L, Fe 9.1170 mg/L, and Mn 15.7809 mg/L, all of which exceed environmental quality standards. The optimum chemical dosage was determined based on daily flow variations, including 1% lime solution, 25% NaOH, 1% alum, and 1% Curifloc. The neutralization unit (235.7 m³) and coagulation unit (137.4 m³) are each equipped with agitators and pH/TSS sensors integrated with ESP32. The system enables real-time monitoring through an LCD display and an internet-based application. This design is expected to enhance treatment efficiency and ensure that the quality of treated water consistently meets environmental standards.