Model pengolahan limbah cair industri percetakan dengan proses Flokulasi Koagulasi secara Batch

SUDARSONO, Wiratni, ST.,MT.,Ph.D

2007 | Tesis | S2 Teknik Mesin (Tek. Pengelolaan dan Pemanfaatan

Industri percetakan mempunyai potensi menghasilkan limbah cair yang dapat mencemarkan lingkungan hidup. Pada umumnya limbah cair perusahaan atau industri percetakan terjadi akibat pencucian plat film dan peralatan cetak berupa sisa-sisa tinta, thiner, terpentin, bensin, minyak tanah, dan detergen. Hasil analisis laboratorium dari limbah cair suatu percetakan sebelum dilakukan treatment menunjukkan kadar timbal (Pb) 656, 60 mg/L, senyawa aktif biru metilen 26,30 mg/L, minyak/lemak 15,41 mg/L serta pH 12. Untuk itu perlu kiranya ada perhatian untuk pengolahan air limbah percetakan tersebut. Pada penelitian ini metode yang digunakan adalah metode koagulasi flokulasi. Adapun koagulan/flokulan yang digunakan adalah kapur aktif Ca(OH)2, tawas Al2(SO4)3 dan kalsium klorida (CaCl2). Penelitian ini diperoleh hasil terbaik adalah menggunakan kapur aktif 20 g/L, tawas 1,5 g/L dan kalsium klorida 5 g/L, karena dapat menurunkan kadar Pb sampai 0.08 mg/L, senyawa aktif biru metillen 0,09 mg/L, minyak / lemak tidak terdeteksi dan pH menjadi 8,20. Dari hasil pengolahan limbah tersebut sudah sangat baik karena dari ketetapan Pemerintah Daerah Istimewa Yogyakarta batasan yang diijinkan adalah; timbal (Pb) 10 mg/L, senyawa aktif biru metilen 0,1 mg/L, minyak/lemak 5 mg/L serta pH 6,0-9,0. Limbah tinta dapat digunakan sebagai pengawet kayu dan sludge dapat dipergunakan sebagai bahan batako dengan campuran 1 Pc : 1 Slg : 10 pasir dengan kekuatan tekan 56,66 kg.f/cm2

Industrial printing companies potentially produce liquid waste, which can be harmful for the environment. Generally, liquid waste from these printing companies is resulted from washing process of the film plste and other printing equipment. Usually the liquid waste contains ink left-over, inking, thinner, turpentine, gasoline, kerosene and detergen. Laboratory analysis of the liquid waste showed that the waste mainly contained lead (Pb) with the concentration of 656,60 mg/L and also contained other compounds like 26,30 mg/L blue methylene compound, 15,41 mg/l oil / fat. In general, the waste exhibited pH value of 12. These data were far beyond the limits set by the local government. Therefore, it is necessary to put careful efforts to separate the polluting compound before draining the liquid waste to the environment. This research is focused to study flocculation / coagulation method to separate the pollutan in the waste especially to lower the Pb content. Experiments resulted in an optimum composition for the liquid waste (specified above), which contained of 20 g/L Ca (OH)2, 1,5 g/L Al2(SO4)3, and 5 g/L CaCl2. With the aforementioned composition of flocculant, it was shown that Pb content decreased to 0,08 mg/L, blue methylene compound decreased to 0,09 mg/L, and oil/fat was not detected. Final pH value was 8,20. These values have well met the requirement set by loca government ( max .10 mg/L Pb, 0,1 mg/L blue methylene compound, 5 mg/L oil / fat, and pH value between 6-9). Ink left-over skimmed from the waste can be used for wood preservatives and the sludege from coagulation process can be utilized for “batako” production with the composition of 1 PC : 1 Sludge : 10 Sand.

Kata Kunci : Pengolahan Limbah Cair,Industri Percetakan,Flokulasi Koagulasi,Batch, Coagulation Flokulation, Inking Waste Exploiting and Sludge