KINETICS OF AN AZO DYE DECOLOURIZATION USING UV/H2O2 TECHNIQUE

Abstract: Advanced oxidation process using UV/H2O2 was used to remove CI Reactive Red 195A from textile wastewater. UV radiation source was a low-pressure mercury arc lamp, 60W emitting at 253.7nm. In this work, the effects of initial hydrogen peroxide dosage, dye concentration, pH and temperature were examined to study the kinetics of dye decolourisation through UV/H2O2 process. The aim is to find the optimum treatment conditions for practical applications of dye removal from wastewater and to obtain information relevant for the possible scale-up of the degradation process. In general, the result demonstrates that the decolourization reaction was found to follow first order kinetics with respect to the dye concentration. Keywords: Azo-dye, Decolourization, Kinetics, Textile, UV/H2O

OPTIMIZATION OF CI REACTIVE RED 195A DEGRADATION USING PHOTOCHEMICAL METHOD

Abstract: Photochemical method using UV/H2O2 was utilized to decolourize CI Reactive Red 195A. In this work, the UV radiation source was a low-pressure mercury arc lamp (60W emitting at 253.7nm). Using the combined UV/H2O2 process, the effects of initial hydrogen peroxide dosage, dye concentration, pH and temperature were examined to determine the optimum operating conditions of the treatment process. Complete decolourization of 100 mg/L dye was achieved in the relatively short time of 20-30 minutes irradiation. Faster decolourization was achieved at low pH and high temperature. The removal rate increased with increasing initial concentration of H2O2 up to an optimum value (approximately 900 mg H2O2/L). However, even after near complete removal of the active dye from the solution, approximately 60% of the COD was still remaining, indicating only partial breakdown of the dye molecule. In general, the result indicates that the UV/H2O2 technology has a good potential for removing dyestuff from wastewater, but additional treatment is required to achieve further degradation of the organic intermediates and possibly reduce the UV irradiation time and chemical consumption. Keywords: Decolourization, Photochemical, Reactive azo-dye, Textile, UV/H2O

DETERMINATION OF DEOXYGENATION RATE OF URBAN RIVER USING MODIFICATION METHODS FOR CITEPUS RIVER WATER, BANDUNG, INDONESIA

River water quality modeling needs appropriate and suitable coefficients especially in application for specific river like urban river. Aim: This study aims to determine the value of the coefficient with a short term duration and a variable test time span.  Several ways and methods of determining the rate of deoxygenation are developed according to the characteristics of the river and the environment. Modification method was applied in this research in which the test time span was unequal. The river chosen in this study is the Citepus River, Bandung, Indonesia representing an urban river in a tropical country. Methodology and Results: Sampling was carried out in the dry season. The laboratory analysis method used in determining the rate of deoxygenation uses the Slope Method of data from the short term incubation, which is ten days. The results showed that the Thomas Slope method's deoxygenation rate (K1) was 0.095 per day in the upstream segment, 0.917 per day in the middle segment, and 0.180 per day in the downstream segment. While the Ultimate BOD (La) value is 46.95 mg/l in the upstream segment, 38.70 mg/l in the middle segment, and 37.60 mg/l in the downstream segment. Conclusion, significance, and impact of study: The results of this study show that the value of the deoxygenation rate is similar to the theoretical surface water conditions. However, in the upstream segment, there is still a low deoxygenation rate value due to non-optimal activity of microorganisms. This findings will be very useful both in water quality modeling and river management

PENYISIHAN ZAT WARNA INDIGO (C.I. VAT BLUE 1) MENGGUNAKAN PROSES FOTO-FENTON

Dengan semakin berkembangnya industri seperti industri tekstil, yang selain memberikan manfaat juga menimbulkan adanya pencemaran. Masalah yang ditimbulkan salah satunya adalah kehadiran zat warna. Untuk itu dibutuhkan teknologi pengolahan limbah yang dapat menyisihkan warna dari limbah secara tuntas yang diharapkan dapat digunakan kembali dalam proses produksi. Dalam studi penelitian ini akan dibahas mengenai penyisihan limbah artifisial zat warna Indigo (C.I Vat Blue 1) yang menyerupai konsentrasi warna limbah tekstil sesungguhnya menggunakan proses Foto-Fenton (UV/H2O2/Fe2+). Pengolahan ini menggunakan konsentrasi warna 100 mg/l dengan variasi konsentrasi Fe2+ dan H2O2 yang berlangsung secara batch. Variasi H2O2 yang digunakan yaitu 250, 500, 750, 1000, dan 1250 mg/l serta variasi Fe2+ sebesar 30, 60, 90 dan 120 mg/l. Pada penelitian pendahuluan dilakukan uji penyisihan warna menggunakan perlakuan tunggal yaitu : warna saja, penyinaran UV saja, penambahan H2O2 saja dan penambahan Fe2+ saja serta perlakuan ganda (kombinasi dua perlakuan) yaitu : kombinasi H2O2/Fe2+, kombinasi UV/H2O2 dan kombinasi UV/Fe2+ selama 35 menit pengolahan. Hasil yang diperoleh dari penelitian pendahuluan menunjukkan bahwa penyisihan yang terjadi kurang efektif yakni < 30% dan < 60%. Oleh sebab itu dilakukan penelitian selanjutnya menggunakan perlakuan lengkap (kombinasi tiga perlakuan) yaitu kombinasi UV/H2O2/Fe2+ (proses Foto-Fenton). Dari hasil pengolahan menggunakan proses Foto-Fenton menunjukkan bahwa variasi konsentrasi H2O2 dan Fe2+ optimum yakni pada pemakaian konsentrasi H2O2 : 750 mg/l dan Fe2+ sebesar 120 mg/l selama 35 menit pengolahan, penyisihan yang terjadi telah mencapai 94%. Dengan hasil penelitian ini dapat memberikan gambaran bahwa proses Foto-Fenton efektif dalam menyisihkan warna Indigo pada limbah cair artifisial. Nilai ekonomi dari pengolahan limbah artifisial menggunakan proses Foto-Fenton ini sebesar Rp 2881/liter limbah

EFEKTIFITAS TANAH GAMBUT DALAM PENYISIHAN WARNA DAN KEKERUHAN PADA AIR GAMBUT (Studi Kasus Air Gambut Kecamatan Buru Kepulauan Riau)

Penduduk yang tinggal di daerah Kecamatan Buru Kepulauan Riau menghadapi kesulitan memperoleh air bersih untuk keperluan rumah tangga terutama untuk keperluan air minum. Hal ini disebabkan karena sumber air yang terdapat di daerah tersebut adalah air gambut yang berwarna cokelat dan bersifat asam. Adapun karakteristik air gambut yang ada di lokasi studi yaitu, intensitas warnanya tinggi sebesar 316 unit Pt-Co, kekeruhan 8 NTU dan pH 4,07. Bila kita lihat karakteristik tersebut masih jauh melebihi baku mutu persyaratan kualitas air minum menurut Keputusan Menteri Kesehatan RI No.907/Menkes/SK/VII/2002. Mengingat kebutuhan air minum yang sangat mendesak, maka diperlukan penelitian dan pengembangan teknologi pengolahan air gambut yang ekonomis malalui pemanfaatan bahan setempat dalam hal ini tanah gambut. Apabila dilihat dari kandungan senyawa kimia didalamnya seperti alumunium , besi dan lain-lain, diduga tanah gambut dapat digunakan sebagai koagulan dan adsorban. Pada penelitian ini dilakukan beberapa variasi percobaan yaitu variasi dosis koagulan. Dari hasil penelitian didapat dosis optimum pembubuhan tanah gambut sebesar 30 gr/l, dengan efesiensi penyisihan untuk warna sebesar 95 %, untuk kekeruhan sebesar 90% dan pH mengalami penurunan

PENYISIHAN WARNA LIMBAH CAIR TEKSTIL PT. GRANDTEX (WARNA INDIGO C.I. VAT BLUE 1) DENGAN PROSES PHOTO-FENTON

Limbah cair industri tekstil merupakan komponen air buangan yang berasal dari proses perwanaan. Limbah cair industri tekstil dapat diamati dengan mudah, karena memiliki warna yang relatif pekat. Warna merupakan suatu senyawa kompleks aromatik yang biasanya sukar untuk diuraikan, sehingga dibutuhkan teknologi pengolahan limbah yang dapat menyisihkan warna. Proses Photo-Fenton merupakan kombinasi reaksi reagen Fenton (H2O2/Fe2+) dengan sinar ultra violet (UV). Kehadiran reaksi reagen Fenton dan sinar ultra violet akan menghasilkan radikal hidroksil (OH˙) yang dapat mengoksidasi senyawa organik. Penelitian ini bertujuan untuk mengetahui tingkat efisiensi proses Photo-Fenton dalam menyisihkan warna pada limbah cair tekstil. Pada penelitian ini digunakan limbah cair tekstil asli dengan konsentrasi 97-98 mg/l serta daya lampu UV 15 watt. Dilakukan uji penyisihan warna menggunakan perlakuan tunggal (warna saja, penyinaran dengan UV, penambahan H2O2 dan penambahan Fe2+), perlakuan ganda (kombinasi H2O2/Fe2+, kombinasi UV/H2O2 dan kombinasi UV/Fe2+) dan perlakuan lengkap (UV/ H2O2/Fe2+) selama 35 menit pengolahan. Variasi Fe2+ yang digunakan adalah 120 mg/l; 135 mg/l dan 150 mg/l, sedangkan untuk variasi H2O2 yang digunakan adalah 500 mg/l; 625 mg/l dan 750 mg/l. Dari hasil penelitian menunjukkan pengolahan limbah dengan perlakuan tunggal dan ganda belum mampu menyisihkan warna limbah cair tekstil dengan penyisihan warna yang terjadi 80%. Berdasarkan penelitian utama pada pengolahan dengan perlakuan lengkap (kombinasi tiga perlakuan) yaitu : UV/H2O2/Fe2+, kondisi optimal dalam penyisihan zat warna limbah tekstil tercapai dengan pemakaian (Fe2+) = 150 mg/l dan (H2O2) = 625 mg/l yaitu sebesar 88,53% dengan pertimbangan teknis dan ekonomis

Integrated chemical and biological treatment process to remove colour compounds from wastewater

Coloured wastewater, particularly from non-natural sources, is aesthetically\ua0unacceptable, hinders light penetration, damages the quality of the receiving streams.\ua0and may be toxic to biological wastewater treatment systems, to food chain organisms\ua0and to aquatic life. Large amounts of coloured wastewater that contain reactive azo\ua0dyes are generated especially from the textile industry, but there are also other sources\ua0of colour discharges to sewers and the environment. The treatment of reactive azo\ua0dyes has become a major concern since they are difficult to remove by means of\ua0conventional treatment methods. Furthermore, many break-down products of azo dyes\ua0are toxic and resistant to elimination by biological treatment.To effectively treat such wastewater, often a combined chemical and\ua0biological oxidation process is required, as purely biological treatment is usually very\ua0slow or not possible. Advanced oxidation processes (AOPs) can improve the\ua0biodegradability of refractory organic compounds through the use of short-lived, very\ua0reactive hydroxyl radicals (0H*). Nevertheless, total mineralization is quite difficult\ua0to achieve except when long reaction times are applied in the system. Biological processes are far more efficient and cost-effective for smaller molecules which are\ua0usually produced from the AOPs operation. The main objective of this study was to\ua0investigate the removal process of a reactive azo dye (C.I. Reactive Red 195A) using\ua0the integrated UV/MH2O2 and aerobic biological process aiming at minimal chemical\ua0and energy consumption, while reducing the toxic or inhibitory compounds to enable\ua0rapid and near complete biological degradation.In this PhD thesis, the colour and soluble chemical oxygen demand (sCOD)\ua0removal performance of various treatments, such as aerobic biofilm processes, UV\ua0irradiation, H2O2 addition and combinations of these approaches, were investigated. In\ua0addition, the degradation products and toxicity effects of the integrated UV/MH2O2 and\ua0aerobic biofilm process were also evaluated. To evaluate the practical applicability of\ua0the process, the main operating costs for the treatment process were also estimated.Using only an aerobic biological reactor as single treatment method showed\ua0insignificant dye and sCOD removals. This was due to the non-biodegradable nature\ua0of the dye. Additionally, neither H2O2 addition nor UV irradiation alone were able to\ua0considerably reduce the dye and sCOD concentrations. Only the combined process of\ua0UV/MH2O2 gave significant removals for both parameters. In this work, the UV\ua0radiation source was a low-pressure mercury arc lamp (60W emitting at 253.7nm).\ua0Using the combined UV/MH2O2 process, the effects of initial hydrogen peroxide\ua0dosage, dye concentration, pH and temperature were examined to determine the\ua0optimum operating conditions of the treatment process. Complete decolourization of\ua0100 mg/L dye was achieved in the relatively short time of 20-30 minutes irradiation.\ua0Faster decolourization was achieved at low pH and high temperature. The removal\ua0rate increased with increasing initial concentration of H2O2 up to an optimum value\ua0(approximately 900 mg H2O2/L). However, for practical applications an initial pH of\ua08 (or lower), temperature of 30oC, and a H2O2 dosage of about 3 times the dye\ua0concentration was identified as the most appropriate conditions for the chemical\ua0treatment. The decolourization reaction was found to follow first order kinetics with\ua0respect to the dye concentration.\ua0 \ua0 \ua0 However, even after near complete removal of the active dye from the\ua0solution, approximately 60% of the COD was still remaining, indicating only partial\ua0\ua0 breakdown of the dye molecule. Besides, the electric energy per order (Eeo) value of\ua0the system to obtain near complete decolourization was quite high (48.6kWh/m3/order) due to the required high UV dose, representing high electrical power\ua0costs for the treatment process.\ua0 \ua0 \ua0 \ua0 \ua0 \ua0 \ua0\ua0....................

Optimization of integrated chemical-biological degradation of a reactive azo dye using response surface methodology

The integrated chemical-biological degradation combining advanced oxidation by UV/H2O2 followed by aerobic biodegradation was used to degrade C.I. Reactive Azo Red 195A, commonly used in the textile industry in Australia. An experimental design based on the response surface method was applied to evaluate the interactive effects of influencing factors (UV irradiation time, initial hydrogen peroxide dosage and recirculation ratio of the system) on decolourisation efficiency and optimizing the operating conditions of the treatment process. The effects were determined by the measurement of dye concentration and soluble chemical oxygen demand (S-COD). The results showed that the dye and S-COD removal were affected by all factors individually and interactively. Maximal colour degradation performance was predicted, and experimentally validated, with no recirculation, 30 min UV irradiation and 500 mg H2O2/L. The model predictions for colour removal, based on a three-factor/five-level Box-Wilson central composite design and the response surface method analysis, were found to be very close to additional experimental results obtained under near optimal conditions. This demonstrates the benefits of this approach in achieving good predictions while minimising the number of experiments required. (c) 2006 Elsevier B.V. All rights reserved

A laboratory assessment of the impact of brewery wastewater discharge on sulfide and methane production in a sewer

The impact of brewery wastewater discharge on sulfide and methane production in a sewer was assessed. Experiments were carried out on laboratory scale sewer reactors consisting of both an experimental and a control reactor. The control reactor was intermittently fed with real fresh sewage while the experimental reactor was fed with a mixture of brewery and domestic wastewater at two different proportions (10 and 25% v/v). 10% v/v discharge of brewery wastewater increased the H2S and CH4 production rates in the sewer reactor by 40% and 30%, respectively. When the brewery wastewater fraction was increased to 25% v/v, the H2S production rate of the experimental reactor decreased to the level of the control reactor. In contrast, the CH4 production rate maintained at a level that was 30% higher than that in the control reactor. These results indicate that the discharge of brewery wastewater into sewers can give negative impacts in relation to odour and corrosion management of the systems and will increase the greenhouse gas emissions from sewers. The study also reveals that the impact of trade waste on the biological reactions in sewers is complex, and requires careful experimental assessment in each case