KAJIAN INSTALASI PENGOLAHAN AIR LIMBAH INDUSTRI ELEKTROPLATING YANG EFISIEN

Abstract

Dalam rangka menurunkan biaya investasi dan operasiona llimbah industri elektroplating diperlukan pengkajian terhadap berbagai teknologi pengolahan air limbah industri elektroplating. Pada penelitian ini teknologi pengolahan air limbah untuk industri elektroplating yang dikaji adalah Proses Kimia-Fisik dengan Teknologi Tangki Berpengaduk aliran kontinyu dan Proses Pertukaran Ion dengan Teknologi Unggun Diam (fixed bed).

Penelitian ini bertujuan untuk menghasilkan suatu proses dan teknologi pengolahan air limbah industri elektroplating yang efisien dilihat dari segi biaya operasionalnya, serta kualitas air hasil pengolahan yang memenuhi standar Baku Mutu Air Limbah.

Penelitian dengan proses kimia-fisik menggunakan bahan kimia ferro sulfat (FeSO4) sebagai reduktor, natrium hidroksida (NaOH) dan kalsium hidroksida (Ca(OH)2) sebagai presipitat (bahan pengendap). Variabel proses pada kombinasi ferro sulfat-natrium hidroksida : Derajat keasaman (pH) : 5, 7, 9, 11, dan 13, sedangkan pada kombinasi ferro sulfat-kalsium hidroksida : derajat keasaman (pH) : 5, 7, 9 dan 11 serta laju alir air limbah : 200, 400, 600, 800, 1000 ml/menit.

Penelitian dengan proses pertukaran ion menggunakan resin kation sebagai penukar ion logam berat bermuatan positif (Cr+3, Cu+2, Zn+2, Pb+2 dan Cd+2), dan resin anion penukar ion logam berat bermuatan negatif (Cr2O7
-2 dan CN-). Variabel proses : berat resin kation dan anion : 500, 750, 1000, 1250 gram, volume air terolah : 20, 40, 60, 80, 100, 120, 140, 160, 180 dan 200 liter serta pengujian terhadap resin yang telah diregenerasi dengan mempergunakan larutan natrium hidroksida 5% berat.

Hasil penelitian menunjukan bahwa proses kimia-fisik dan pertukaran ion dapat menurunkan konsentrasi ion logam berat air limbah industri elektroplating hingga dibawah nilai baku mutu air limbah, pada proses kimia-fisik kondisi terbaik pada pH 9 dan laju alir 400 ml/menit, biaya operasional dengan kombinasi ferro sulfat-natrium hidroksida sebesar Rp 7.150/m3, ferro slufat-kalsium hidroksida Rp 51.500/m3, waktu tinggal tangki reduksi : 24 menit, tangki presipitasi 22 menit dan clarifier 1,5 jam.

Pada proses pertukaran ion jika resin dipergunakan sekali dalam operasional, biaya operasionalnya Rp 250.000/m3, tetapi jika resin dipergunakan berulang-ulang dengan regenerasi biaya operasional Rp 1250/m3.

In order to decrease the investation and operational cost of electroplating industry waste, study on various kind of electroplating industry waste water treatment technology is needed. In this research, the studied waste water treatment technology for electroplating industry was Physic-Chemistry Process conducted with the technology of Continuous Stream Tank with Stirring Rod and Ion Exchange Process with Fixed Bed Technology.

This research aimed to yield an efficient electroplating industry waste water treatment technology and process measured from it’s operational cost aspect, and also the quality of treatment product water which meets Waste Water Quality Standard.

Research was conducted with physic-chemistry process using FeSO4 as reductor, NaOH and Ca(OH)2 as precipitator. Process variables at FeSO4-NaOH combination : acidity degree (pH) : 5, 7, 9, 11, dan 13; at FeSO4-Ca(OH)2 combination : acidity degree (pH) : 5, 7, 9, dan 11, and waste water flow velocity : 200, 400, 600, 800, 1000 ml/minute.

Research was conducted with ion exchange process using cation resin as ion exchanger for heavy metal with positive ion (Cr+3, Cu+2, Zn+2, Pb+2, and Cd+2), and ion exchanger anion resin for heavy metal with negative ion (Cr2O7
-2 and CN-). Process variables : the weight of cation and anion resin : 500, 750, 1000, 1250 gram, the volume of processed water : 20, 40, 60, 80, 100, 120, 140, 160, 180, and 200 litre, and testing over resin which had been regenerated using NaOH solution with 5% weight.

The result of research showed that physic-chemistry process and ion exchange could decrease the concentration of electroplating industry waste water heavy metal ion down to the quality standard amount of waste water, at physic-chemistry process with the best condition at pH 9 and flow velocity 400 ml/minute, operational cost with FeSO4-NaOH combination as much as Rp 7.150/m3, FeSO4-Ca(OH)2 Rp 51.500/m3, reduction tank left time : 24 minutes, precipitation tank 22 minutes and clarifier 1,5 hours.

At ion exchange process if resin was used once at operational, the operational cost was Rp 250.000/m3, but if resin was used repeatedly with regeneration then the operational cost was Rp 1250/m3.