PENINGKATAN KINERJA MEMBRAN ULTRAFILTRASI ALIRAN DEAD-END PADA PENYISIHAN BAHAN ORGANIK DALAM EFLUEN IPAL DOMESTIK DENGAN PRA-PERLAKUAN ADSORPSI

Salah satu kendala yang membatasi kinerja membran ultrafiltrasi (UF) yaitu fouling membran. Keberadaan Bahan Organik (BO) merupakan salah satu penyebab utama terjadinya fouling membran pada air efluen IPAL Domestik. Oleh karena itu, perlu dilakukan pra-perlakuan adsorpsi karbon aktif untuk mengurangii foulingi dani meningkatkani performai membrani UF. Penelitian ini bertujuan untuk mengetahui proses pengolahan air efluen dengan kondisi terbaik pada proses hibrid adsorpsi dan Ultrafiltrasi (UF) selulosa asetat (SA), serta menganalisis terbentuknya fouling membran pada proses hibrid adsorpsi dan UF-SA. Karbon aktif yang digunakan pada rencana penelitian ini adalah Powdered Activated Carbon (PAC) dengan interval variasi dosis 25 mg/L pada rentang 25 mg/L-200mg/L serta pH 4. Metode yang digunakan pada proses pra-perlakuan adsorpsi menggunakan sistem batch dengan pengadukan adsorpsi 180 rpm selama 240 menit. Kemudian, dialirkan pada membran UF-SA menggunakan sistem aliran dead-end dengan variasi tekanan operasi 1-3 bar dengan interval 0,5 bar pada pH 4 selama 120 menit. Selanjutnya dicari kondisi terbaik proses hibrid adsorpsi dan UF-SA dengan cara mengatur dosis optimum (dinaikkan maupun diturunkan), sehingga didapatkan tiga variasi dosis. Analisis kandungan BO dilakukan melalui pengukuran parameter Dissolved Organic Carbon (DOC), UV254, E4/E6 , dan UV456 menggunakan TOC Analyzer dan Spektrofotometer UV serta karakterisasi membran dengan permeabilitas. Hipotesis dari penelitian ini adalah pra-perlakuani adsorpsii karboni aktifi berpengaruh untuki mereduksii foulingi pada membrani UF-SA, dan model Modified Fouling Index (MFI) dapat menggambarkan pembentukan fouling pada proses hibrid adsorpsi dan UF-SA pada penyisihan air efluen.

PENGARUH PRA-PERLAKUAN ADSORPSI KARBON AKTIF TERHADAP FOULING MEMBRAN ULTRAFILTRASI POLISULFON (UF-PSf) PADA PENYISIHAN BAHAN ORGANIK ALAMI (BOA) AIR GAMBUT

Fouling merupakan salah satu kendala yang membatasi kinerja membran ultrafiltrasi (UF). Keberadaan Bahan Organik Alami (BOA) menjadi penyebab utama terjadinya fouling membran pada air gambut. Pra-perlakuan adsorpsi mampu menjadi solusi untuk mengurangi fouling dan meningkatkan performa membran UF polisulfon (UF-PSf). Penelitian ini bertujuan untuk menyelidiki pengaruh pra-perlakuan adsoprsi terhadap perubahan nilai fluks pada membran UF- PSf, dan menganalisis model pembentukan fouling yang paling tepat untuk menggambarkan proses hibrid adsorpsi dan UF-PSf. Proses hibrid adsorpsi dan UF-PSf dilakukan pada kondisi optimum dengan pH 4 dan dosis optimum Powdered Activated Carbon (PAC) 1040 mg/L pada tekanan 1-3 bar. Tekanan operasi terbaik terjadi pada tekanan 3 bar dengan nilai fluks permeat sebesar 85,064 L/m2.jam dan rejeksi BOA sebesar 85,24% (UV254) dan 85,07% (KMnO4). Modified Fouling Index (MFI) merupakan pemodelan yang tepat untuk menggambarkan pembentukan fouling pada proses hibrid adsorpsi dan UF-PSf pada penyisihan BOA air gambut. Tekanan 1 bar memiliki potensi fouling yang tinggi dengan nilai R2 sebesar 0,998.

Monitoring Biofouling Potential Using ATP-Based Bacterial Growth Potential in SWRO Pre-Treatment of a Full-Scale Plant

Several potential growth methods have been developed to monitor biological/organic fouling potential in seawater reverse osmosis (SWRO), but to date the correlation between these methods and biofouling of SWRO has not been demonstrated. In this research, the relation between a new adenosine triphosphate (ATP)-based bacterial growth potential (BGP) test of SWRO feed water and SWRO membrane performance is investigated. For this purpose, the pre-treatment of a full-scale SWRO plant including dissolved air flotation (DAF) and two stage dual media filtration (DMF) was monitored for 5 months using BGP, orthophosphate, organic fractions by liquid chromatography coupled with organic carbon detection (LC-OCD), silt density index (SDI), and modified fouling index (MFI). Results showed that particulate fouling potential was well controlled through the SWRO pre-treatment as the measured SDI and MFI in the SWRO feed water were below the recommended values. DAF in combination with coagulation (1–5 mg-Fe3+/L) consistently achieved 70% removal of orthophosphate, 50% removal of BGP, 25% removal of biopolymers, and 10% removal of humic substances. Higher BGP (100–950 µg-C/L) in the SWRO feed water corresponded to a higher normalized pressure drop in the SWRO, suggesting the applicability of using BGP as a biofouling indicator in SWRO systems. However, to validate this conclusion, more SWRO plants with different pre-treatment systems need to be monitored for longer periods of time.

Ozonation Pretreatment for Reduction of Landfill Leachate Fouling on Membranes: A Response Surface Methodology Analysis

Batch ozonation was performed to assess its efficacy as a pretreatment for reverse osmosis (RO) membranes for treating leachate with high concentrations of recalcitrant organic compounds. Leachate samples from two different landfills were collected and characterized. The modified fouling index (MFI) was used to estimate the fouling potential of raw and ozonized leachates. A response surface experimental design was applied to optimize operational pH and ozone dose. The results demonstrate that the best operational conditions are 1.5 g/L of O3 at pH 12.0 and 1.5 g/L of O3 at pH 9.0 for Landfills 1 and 2, which reduce MFI by 96.22% and 94.08%, respectively. Additionally, they show toxicity factor decays of 98.44% for Landfill 1 and 93.75% for Landfill 2. These results, along with the similar behavior shown by leachate samples from distinct landfills, suggest that ozonation is a promising technology to fit this kind of wastewater into the requirements of RO membranes, enabling their use in such treatment.

A modified fouling index (MFI40) and fouling predicting approach for ultrafiltration of secondary effluents

Fouling indices for evaluating fouling propensity of secondary effluents (SEF) as feed of ultrafiltration (UF) systems are important parameters for the design and operation of the UF process. However, limited fouling indices have been developed and applied for UF feedwater. This study (i) established a modified UF fouling index (MFI40) by raising operating pressure from 30 psi in a traditional MFI test to 40 psi. Standard deviation of MFI40 tests was lower than that of traditional MFI by 68.6%, indicating better stability and repeatability of MFI40. It (ii) investigated the combined effects of UF feedwater characteristics on MFI40. Biopolymers and turbidity played a dominant and secondary positive role in the MFI40, respectively. The effect of conductivity on MFI40 changed from positive to negative with a turbidity increase. It also (iii) validated the MFI40 in both laboratory- and pilot-scale UF membrane units, and UF fouling rates were linearly correlated to the MFI40 of their feeds, and (iv) explored the practical use of the MFI40. It was applied to determine the maximum allowable UF feedwater quality (MFI40max), which could be used to select an appropriate pre-treatment process. A fouling predicting model was established based on the feedwater MFI40 and the operating flux, with an average predicting error of 26.8%.

Assessment of membrane fouling indices during removal of reactive dye from batik wastewater

‘Batik’ is known as one of the most popular textile industries in Malaysia, and it produces wastewater in its processing. The wastewater contains reactive dye and is released into drains as well as rivers. It could cause harm to the environment and interrupt the food chain due to the chemicals contained in it. The aim of the present study is to determine the flux performance and modified fouling index using ultrafiltration (MFI-UF) by using different membrane materials, feed concentrations and feed chemistry. The sample was obtained from Romi Batik located at Chendering Terengganu. Two UF membranes were used, with the membrane materials made from cellulose acetate and polyvinylidene fluoride (PVDF). The permeate flux and fouling indices were investigated at the solution pH values of 3 and 7 for different concentrations. It was clearly observed that the highest percentage dye rejection and MFI-UF obtained at pH 7 using a PVDF membrane was a value of 85.3792% and 72,088 s/L2, respectively. Overall results revealed that an ultrafiltration process can be used to treat reactive dye from textiles before it is channelled into the sea or rivers, and has great potential to be commercialized as a new alternative in dye wastewater treatment.