PENGOLAHAN LIMBAH DOMESTIK SALINITAS TINGGI (SALINE DOMESTICWASTEWATER) DENGAN TEKNOLOGI MEMBRAN

Abstract

Kondisi geografis Semarang yang terletak di pantai utara Jawa dengan ketinggian hampir sama dengan permukaan air laut disertai populasi dan pertumbuhan ekonomi yang cukup tinggi di kawasan pesisir berdampak pada tingginya kerentanan Semarang bagian utara terhadap banjir rob. Hal ini menyebabkan penurunan kualitas air permukaan dan air tanah sehingga terjadi krisis air layak konsumsi. Tingginya kuantitas limbah domestik yang bercampur dengan luapan rob yang terjadi hampir setiap hari di kawasan pesisir Genuk berpotensi untuk digunakan kembali (reuse) menjadi sumber air minum sebagai solusi kelangkaan air tawar di kawasan pesisir. Teknologi membran terutama membran nanofiltrasi (NF) merupakan salah satu alternatif yang menjanjikan dalam wastewater reuse dengan kadar garam tinggi khususnya pada saline domestic wastewater. Dalam studi ini akan diobservasi kinerja membran NF270 dalam mengolah saline domestic wastewater menjadi sumber air minum dan efek garam terhadap rejeksi komponen organik. Pada penelitian ini diuji kinerja membran dengan pengukuran fluks dan tingkat rejeksi limbah sintetik maupun limbah asli yang melibatkan mekanisme berupa sieving (steric effect) dan charge effect. Pada larutan limbah sintetik tunggal, NF270 mampu menurunkan konsentrasi Total Dissolve Solid (TDS) sebesar 42.09 – 50.63 %, Chemical Oxygen Demand (COD) maksimal 81.29 % serta klorida sekitar 30 – 40 % (larutan NaCl) dan 61,29 – 70.97 % (larutan CaCl2). Kombinasi garam dan komponen netral (glukosa) berpengaruh signifikan terhadap retensi COD maupun klorida. Semakin tinggi tekanan justru menurunkan tingkat rejeksi COD menjadi 49.63 % serta klorida 40.32 % (larutan CaCl2), sedangkan retensi klorida pada larutan campuran NaCl-glukosa lebih tinggi dibandingkan larutan NaCl tunggal. Rejeksi pada limbah asli untuk parameter TDS, COD, klorida , nitrit dan minyak lemak berturut-turut sebesar 46.01 %, 58. 67%, 38.71%, 73.86 % serta > 99,98 %. The geographical of Semarang located on the north coast of Java with a height of almost the same as sea level with population and high economic growth in the coastal area has an impact on the high vulnerability of northern Semarang against the rob flood. This causes decrease of the quality of surface water and groundwater resulting in a crisis of water consumption. The high quantity of domestic waste mixed with the overflow of rob that occurs almost every day in the coastal area of Genuk has the potential to be reused as a source of drinking water as a solution of freshwater scarcity in coastal areas. Membrane technology, especially nanofiltration membrane (NF) is one promising alternative in wastewater reuse with high salinity especially in saline domestic wastewater. In this study we will observe the performance of NF270 membrane in processing saline domestic wastewater into drinking water source and salt effect on organic compound rejection. In this study, membrane performance was performed with flux measurement and rejection rate of synthetic waste and original waste involving mechanism of sieving (steric effect) and electrostatic interaction. In a single synthetic solution, NF 270 is able to decrease Total Dissolve Solid (TDS) concentrations by 42.09 - 50.63%, maximum Chemical Oxygen Demand (COD) 81.29% and chloride about 30 - 40% (NaCl solution) and 61,29 - 70.97% (CaCl2 solution). The combination of salt and the neutral component (glucose) had a significant effect on both COD and chloride retention. The higher pressure actually decreases the COD rejection rate to 49.63% and 40.32% chloride (CaCl2 solution), while chloride retention in a solution of NaCl-glucose mixture is higher than a single solution of NaCl. Rejection of the original waste for TDS, COD, chloride, nitrite, oil and grease parameters were 46.01%, 58.67%, 38.71%, 73.86% and > 99,98 %, respectively.