Analisis deposisi kering Timbal (Pb) di udara ambien yang bersumber dari Pembangkit Listrik Tenaga Uap (Batu Bara)
M anusia dalam melakukan aktivitasnya sangat bergantung pada ketersediaan energi, listrik khususnya. Pembangkit listrik di Indonesia umumnya menggunakan bahan bakar batu bara. Batu bara dapat mengandung logam-logam berat seperti timbal (Pb) yang dapat mencemari lingkungan melalui bottom ash (abu dasar) dan fly ash (abu terbang). Di udara ambient, logam berat termasuk Pb terikat pada partikel debu. Tujuan penelitian adalah untuk menganalisis kadar Pb pada batu bara, bottom ash dan fly ash dari PLTU terbesar di Indonesia; menghitung konsentrasi, korelasi dan sebaran total suspended particulate (TSP) dan Pb; menganalisis konsentrasi TSP menggunakan model Gaussian dan validasinya; membandingkan konsentrasi TSP dan Pb terhadap baku mutu udara ambien; serta merekomendasikan upaya pengendaliannya. Penelitian ini menggunakan metode kuantitatif. Sampel Pb pada TSP disampling menggunakan alat High Volume Air Sampler (HVAS). Sampel batu bara dan TSP dianalisis menggunakan X-Ray Fluorescence (XRF) untuk mengetahui kadar Pb. Kadar Pb pada batu bara 2,58ppm, pada bottom ash 14,3ppm dan 16ppm, dan pada fly ash 34,7ppm dan 27,3ppm. Pengukuran di udara ambien dilakukan duplo selama dua hari di tiga titik sampling yaitu Desa Lebak Gede, Dermaga Tongkang dan Pantai Salira. Pada hari pertama, terukur konsentrasi TSP (24 jam) berkisar 53,50–144,36µg/Nm3 dan Pb (24 jam) berkisar 0,01–0,074µg/Nm3 dengan nilai korelasi 0,302. Pada hari kedua, konsentrasi TSP (24 jam) berkisar 74,57–111,54µg/Nm3 dan Pb (24 jam) berkisar ≤ 0,008–0,088µg/Nm3 dengan nilai korelasi 0,338. Pola dispersi sampling TSP menunjukkan daerah terjauh dengan konsentrasi maksimum berada di Desa Mangunreja, Desa Sumuranja dan Desa Pulo Ampel. Pemetaan sampling Pb tidak menunjukkan hasil konklusif. Berdasarkan validasi, model Gaussian memiliki tingkat kepercayaan 83,3%. Model dispersi TSP dan Pb menunjukkan bahwa wilayah terjauh dengan konsentrasi maksimum berada di Desa Sumuranja dan Desa Pulo Ampel. Berdasarkan Peraturan Menteri Negara Lingkungan Hidup No. 12 Tahun 2010 tentang Pengendalian Pencemaran Udara, baku mutu udara ambien 24 jam untuk TSP adalah 230µg/Nm³ dan Pb adalah 2µg/Nm³. Hasil pengukuran menunjukkan konsentrasi TSP dan Pb masih memenuhi baku mutu udara ambien, namun perlu terus dipantau. Upaya pengendalian yang dapat dilakukan adalah mengganti bahan bakar utama PLTU dengan bahan bakar yang tidak mengandung atau rendah kadar logam beratnya, menjaga efisiensi electrostatic precipitator (ESP) pada minimal 95%, serta segera mengolah limbah bottom ash dan fly ash yang dikumpulkan di ash disposal agar abu tersebut tidak terbawa angin dan mencemari lingkungan udara sekitar.
I n carrying out their activities, humans rely heavily on energy, especially electricity. Power plants in Indonesia generally use coal fuel. Coal can contain heavy metals such as lead (Pb) which can pollute the environment through bottom ash and fly ash. In the ambient air, heavy metals include Pb are attached to particles. The research objectives were to analyze Pb concentrations in coal, bottom ash and fly ash from the largest power plant in Indonesia; calculate the concentration, correlation and distribution of total suspended particulate (TSP) and Pb; analyze TSP concentrations using the Gaussian model and its validation; comparing TSP and Pb concentrations to ambient air quality standards (AAQS); and recommend controlling efforts. This study used quantitative methods. Pb in TSP was sampled using a High Volume Air Sampler (HVAS). Samples of coal and TSP were analyzed using X-Ray Fluorescence (XRF) to determine Pb concentrations. Pb concentrations were 2.58ppm in coal, 14.3ppm and 16ppm in bottom ash, and 34.7ppm and 27.3ppm in fly ash. Measurements in ambient air were carried out duplo for two days in three sampling points namely Lebak Gede Village, Tongkang Jetty and Salira Beach. The first day measurement, TSP (24 hours) concentrations ranged from 53.50–144.36µg/Nm3 and Pb (24 hours) ranged from 0.01–0.074µg/Nm3 with a correlation value of 0.302. On the second day, TSP (24 hours) concentrations ranged from 74.57–111.54µg/Nm3 and Pb (24 hours) ranged from ≤0.008–0.088µg/Nm3 with a correlation value of 0.338. The dispersion pattern of TSP sampling show the farthest areas with maximum concentration are in Mangunreja Village, Sumuranja Village and Pulo Ampel Village. The mapping of Pb sampling does not show conclusive results. Based on the validation, the Gaussian model has a confidence level of 83.3%. The model of TSP and Pb dispersions show that the farthest areas with maximum concentration are in Sumuranja Village and Pulo Ampel Village. Based on the Minister of Environment Regulation No. 12 of 2010 concerning Air Pollution Control, the 24-hour AAQS for TSP is 230µg/Nm³ and Pb is 2µg/Nm³. The measurement results show that TSP and Pb concentrations still meet AAQS, but need to be monitored continuously. Control measures that can be taken are replacing the coal with fuels that do not contain or low levels of heavy metals, maintain the efficiency of the electrostatic precipitator (ESP) at a minimum of 95%, and immediately process bottom ash and fly ash wastes collected at ash disposal so they are not transported by the wind and pollutes the ambient air