Pak Roto

α-Pinene is the main component of the most turpentine oils. The hydration of α-pinene with acid catalysts leads to a complex mixture of monoterpenes. In order to obtain more valuable products, the α-pinene in the turpentine can be hydrated in dilute mineral acid solutions to produce α-terpineol. The design of separation processes requires information on phase equilibrium and related thermodynamic properties. This paper reports the results of study on liquid-liquid equilibrium (LLE) of system containing α- pinene + water and α-terpineol + water. Binary LLE for α-pinene + water system, and α-terpineol + water systems were determined by experiment at 301K and atmospheric pressure. The two component mixture was stirred for about 30min, then the mixture was left for about 2h for complete phase separation. The composition of both phases was analyzed by using a Gas Chromatograph. The experimental data were correlated by considering both NRTL and UNIQUAC activity coefficient models. The LLE...

Penelitian ini bertujuan untuk mengembangkan metode analisis kreatinin. Metode yang sering digunakan untuk analisis kreatinin secara spektrofotometri adalah dengan menggunakan Jaffe reaction yaitu mereaksikan kreatinin dengan asam pikrat sehingga menghasilkan senyawa kompleks yang dapat dianalisis dengan menggunakan spektrofotometri UV Vis dalam pelarut air. Pengembangan metode analisis kreatinin dilakukan dengan menambahkanTri octylmethylammoniumchloride (TOMAC) dalam pelarut kloroformsehingga membentuk pasangan ion asam pikrat-kreatinin-TOMA. Larutan organik kemudian dipisahkan dari larutan sampel dan selanjutnya dianalisis dengan menggunakan spektrofotometer UV Vis. Hasil penelitian menunjukkan bahwa uji validasi metode analisis kreatinin dengan menggunakan TOMA memiliki kelinearitas 98%, limit deteksi 1.089 ppm, SENScal 0.0107, SENSanal 1.089, dan presisi 0.3705.

Short-chain alcohols are a group of volatile organic compounds (VOCs) that are often found in workplaces and laboratories, as well as medical, pharmaceutical, and food industries. Real-time monitoring of alcohol vapors is essential because exposure to alcohol vapors with concentrations of 0.15–0.30 mg·L−1 may be harmful to human health. This study aims to improve the detection capabilities of quartz crystal microbalance (QCM)-based sensors for the analysis of alcohol vapors. The active layer of chitosan was immobilized onto the QCM substrate through a self-assembled monolayer of L-cysteine using glutaraldehyde as a cross-linking agent. Before alcohol analysis, the QCM sensing chip was exposed to humidity because water vapor significantly interferes with QCM gas sensing. The prepared QCM sensor chip was tested for the detection of four different alcohols: n-propanol, ethanol, isoamyl alcohol, and n-amyl alcohol. For comparison, a non-alcohol of acetone was also tested. The prepared Q...

ABSTRAKNitrat dan nitrit merupakan sumber nitrogen bagi tanaman. Nitrogen sangat diperlukan tanaman untuk pertumbuhan dan perkembangan. Bentuk-bentuk nitrogen di lingkungan mengalami transformasi sebagai bagian dari siklus nitrogen seperti nitrifikasi dan denitrifikasi. Apabila kadar nitrogen dalam tanah rendah, maka urea digunakan sebagai sumber nitrogen. Perubahan urea menjadi nitrit atau nitrat pada beberapa sampel tanah perlu diketahui. Kadar nitrit dan nitrat yang tinggi dapat meningkatkan pencemaran di dalam tanah. Sampel tanah yang digunakan dalam penelitian ini adalah tanah pasir, tanah sawah, tanah pupuk kompos dan tanah pupuk kandang. Analisis nitrit dan nitrat dilakukan dengan menggunakan pereaksi asam p-amino benzoat (PABA) yang dikopling dengan N-naftiletilendiamin (NEDA) dan reduktor spongy cadmium. Sebelum digunakan untuk analisis nitrit dan nitrat, metode divalidasi terlebih dahulu. Hasil validasi metode analisis nitrit dan nitrat dengan pereaksi PABA/NEDA menunjukka...

Alginate based biopolymer with improved physical and chemical properties after esterification using polyvinyl alcohol (PVA) has been studied for possible application as a hemodialysis membrane. The alginic acid to vinyl alcohol molar ratio was predetermined at 0, 0.1, 0.5 and 1. Mechanical strength, hydrophilicity and Ca(2+) adsorption of the membrane before and after modification were evaluated. The obtained PVA-alginate (PVA-Alg) ester membrane was also confirmed using FTIR and SEM. It shows that the PVA-Alg membrane tensile strength is higher than that of native alginate. The water contact angle of the membrane was found to be around 33-50°. The Ca(2+) adsorption capacity tends to decrease with the increase in molar ratio. Furthermore, the modified PVA-Alg ester membrane achieves better protein adsorption and platelet adhesion than the unmodified one. It also exhibits a dialysis performance of 47.1-50.0% for clearance of urea and 42.2-44.6% for clearance of creatinine, respectively. It is expected that this PVA-Alg ester may challenge cellulose acetate for potential application as hemodialysis membranes.

α-pinene is the main component of most turpentine oils. In order to obtain more valuable products, α-pinene in the turpentine can be hydrated in dilute mineral acid solutions to produce α- terpineol, which can be used as perfume, repellent of insect, antifungal and disinfectant. This paper presents a study on heterogeneous kinetics model for synthesis of α-terpineol from α-pinene. In this work, the two kinetics models both the ideal and the non ideal solution assumption have been developed to quantitatively describe effects of hydration process of α-pinene in aqueous acid solution. The results of this study show that the kinetics model of the hydration of α-pinene can be approached by the heterogeneous model. A good agreement between the experimental data and the model has been observed. Keywords— α-pinene, α-terpineol, hydration, kinetics

LiCoxMn2-xO4 can serve as one of the main candidates for cathode materials for lithium batteries since they are abundant, low cost and environmentally friendly. This study aims to study the synthesis of LiCoxMn2-xO4 by low temperature solid-state reaction and its microstructure determination. Attention is paid more to the mole ratio of Co/Mn in LiCoxMn2-xO4. The compound was characterized by XRD, SEM-EDX, and BET while the analysis of LiCoxMn2-xO4 microstructure was carried out by Direct Method using winPLOTR package program and Diamond using XRD data. The series of LiCoxMn2-xO4 have well–developed cubic crystal structure with Fd3m phase, and the increase in the dopant does not change its structure. The lattice parameters and cell volumes of LiCoxMn2-xO4 tend to decrease with the increase in x values

This study aims at investigating a better condition of calcination at different temperature to produce LiMn2O4 microstructure. In this study, cubic LiMn2O4 was synthesized using a low temperature solid-state reaction. We report, here, MnO2 nanorods synthesis by reflux and their chemical conversion to LiMn2O4. The compound was characterized by XRD and TEM. Further, the analysis of LiMn2O4 microstructure was carried out by Direct Method using winPLOTR package program and Diamond using XRD data. At low calcination temperature, Mn2O3 is present as an impurity, but it disappears along with the increase in calcination temperature. It is also found that solid state reaction at is 750oC give nanoLiMn2O4. The lattice parameters and cell volumes of LiMn2O4 increases with the increase in heating temperature.

An ester of butanediol-alginate has been studied as a possible hemodialysis membrane. With 1,4-butanediol molar ratio of 0.1, 0.5, and 1.0, it showed that the membrane mechanical properties, stability, protein adsorption, platelet adhesion and performance for urea and creatinine clearance are better than that of unmodified alginate. The increase in 1,4-butanediol molar ratio causes hemodialysis ratio to improve, and causes protein adsorption and platelet adhesion at the membrane surface to decrease. In the case of protein adsorption and platelet adhesion, the membrane with the molar ratio of 1.0 has better hemocompatibility properties. In the hemodialysis test for 4 h, using 2.742 mg cm-2 h-1 of urea and 0.058 mg cm-2 h-1 of creatinine flux, this membrane showed that 48.5% of urea and 44.2% of creatinine were cleaned.

Alginate based biopolymer with improved physical and chemical properties after esterification using polyvinyl alcohol (PVA) has been studied for possible application as a hemodialysis membrane. The alginic acid to vinyl alcohol molar ratio was predetermined at 0, 0.1, 0.5 and 1. Mechanical strength, hydrophilicity and Ca(2+) adsorption of the membrane before and after modification were evaluated. The obtained PVA-alginate (PVA-Alg) ester membrane was also confirmed using FTIR and SEM. It shows that the PVA-Alg membrane tensile strength is higher than that of native alginate. The water contact angle of the membrane was found to be around 33-50°. The Ca(2+) adsorption capacity tends to decrease with the increase in molar ratio. Furthermore, the modified PVA-Alg ester membrane achieves better protein adsorption and platelet adhesion than the unmodified one. It also exhibits a dialysis performance of 47.1-50.0% for clearance of urea and 42.2-44.6% for clearance of creatinine, respective...

α-pinene is the main component of most turpentine oils. In order to obtain more valuable products, α-pinene in the turpentine can be hydrated in dilute mineral acid solutions to produce α- terpineol, which can be used as perfume, repellent of insect, antifungal and disinfectant. This paper presents a study on heterogeneous kinetics model for synthesis of α-terpineol from α-pinene. In this work, the two kinetics models both the ideal and the non ideal solution assumption have been developed to quantitatively describe effects of hydration process of α-pinene in aqueous acid solution. The results of this study show that the kinetics model of the hydration of α-pinene can be approached by the heterogeneous model. A good agreement between the experimental data and the model has been observed. Keywords— α-pinene, α-terpineol, hydration, kinetics

An application of Saccharomycess cereviceae biomass immobilized on chitosan (SC-Chi adsorbent) for Pb (II) ion removal was demonstrated. Adsorption experiment was conducted at various mass ratio of Saccharomycess cereviceae biomass to chitosan, ...

Abstrak Nitrat dan nitrit merupakan sumber nitrogen bagi tanaman. Nitrogen sangat diperlukan tanaman untuk pertumbuhan dan perkembangan. Bentuk-bentuk nitrogen di lingkungan mengalami transformasi sebagai bagian dari siklus nitrogen seperti nitrifikasi dan denitrifikasi. Apabila kadar nitrogen dalam tanah rendah, maka urea digunakan sebagai sumber nitrogen. Perubahan urea menjadi nitrit atau nitrat pada beberapa sampel tanah perlu diketahui. Kadar nitrit dan nitrat yang tinggi dapat meningkatkan pencemaran di dalam tanah. Sampel tanah yang digunakan dalam penelitian ini adalah tanah pasir, tanah sawah, tanah pupuk kompos dan tanah pupuk kandang. Analisis nitrit dan nitrat dilakukan dengan menggunakan pereaksi asam p-amino benzoat (PABA) yang dikopling dengan N-naftiletilendiamin (NEDA) dan reduktor spongy cadmium. Sebelum digunakan untuk analisis nitrit dan nitrat, metode divalidasi terlebih dahulu. Hasil validasi metode analisis nitrit dan nitrat dengan pereaksi PABA/NEDA menunjukkan persentase perolehan kembali masing-masing antara 87,15–100,8% untuk nitrit dan 88,16–105,7% untuk nitrat. Setelah ditambah urea sebesar 0,66 g.kg-1 ke dalam tanah, konsentrasi nitrit dan nitrat pada semua sampel tanah mengalami peningkatan. Dari penelitian ini diketahui bahwa peningkatan kadar nitrit dan nitrat setelah ditambahkan urea sangat dipengaruhi oleh kondisi tanah. Abstract Nitrate and nitrite were sources of nitrogen for plants. Nitrogen is indispensable for the growth and development of plants. The forms of nitrogen in the environment undergoes a transformation as part of the nitrogen cycle like nitrification and denitrification. If nitrogen level in the soil is low, urea is used as a source of nitrogen. Changes of urea into nitrite or nitrate in some of soil samples need to be known. The levels of nitrite and nitrate are high can increase pollution in the soil. Some of soil samples which is used in this research were sandy soil, paddy soil, compost soil and manure soil. Analysis of nitrite and nitrate were conducted by using a reagent p-amino benzoic acid (PABA) / N-napthylethylenediamine (NEDA) and spongy cadmium as reductor. Before being used for the analysis of nitrite and nitrate, this method was validated first. The results of validation of nitrite and nitrate analysis method by using a reagents PABA / NEDA showed the percent recovery were respectively 87.15-100.8% for nitrite and 88.16-105.7% for nitrate. After the addition of 0.66 g.kg-1 urea into the soil, nitrite and nitrate concentration in all soil sample has increased. Based on this research was known that the increased levels of nitrite and nitrate after the addition of urea was influenced by soil condition.

Abstrak Metode analisis nitrit dan nitrat perlu dikembangkan untuk memonitor kualitas air minum. Kualitas air sumur untuk parameter nitrit dan nitrat dipengaruhi oleh kondisi lingkungan dan kedalaman air sumur. Penelitian ini bertujuan menganalisis nitrit dan nitrat menggunakan asam p-aminobenzoat (PABA) pada air sumur di daerah perkotaan Yogyakarta. Analisis nitrit didasarkan pada reaksi antara ion nitrit dengan PABA yang membentuk senyawa azo dengan panjang gelombang maksimum 546 nm. Kedalaman air sumur di daerah Catur Tunggal rata-rata > 10 m. Kadar nitrit dan nitrat pada air sumur adalah 0,05-0,09 dan 8,22-36,58 mg/L. Kadar nitrit dan nitrat tersebut memenuhi baku mutu dan aman untuk dikonsumsi. Konsentrasi nitrit dan nitrat pada air RO adalah 0,05 dan 2,72-59,57 mg/L. Kadar nitrit pada air RO tidak memenuhi baku mutu sedangkan kadar nitrat memenuhi baku mutu kecuali RO 5. Kata kunci: air sumur, asam p-aminobenzoat, kualitas air minum, nitrat, nitrit. Abstract The method for analysis nitrite and nitrate had to developed to monitor the drinking water quality. The well water quality, especially for nitrite and nitrate were influenced by environmental conditions and depth of well. This study aims to analyze nitrite and nitrate using p-aminobenzoic acid (PABA) in ground water at urban areas of Yogyakarta. The analysis was based on the reaction between nitrite ions with PABA which form azo compounds with a maximum wavelength of 546 nm. The depth of wells at Catur Tunggal were more than 10 m. Concentration of nitrite and nitrate in well water were 0.05 to 0.09 and 8.22 to 36.58 mg / L. The concentrations met the standard for drinking water quality and was safe for consumption. The concentration of nitrite and nitrate in reverse osmosis (RO) water were 0.05 and 2.72 to 59.57 mg / L. The concentration of nitrite did not meet the standard for drinking water quality while the concentration of nitrate met the standard for drinking water quality except RO 5. PENDAHULUAN Peningkatan jumlah penduduk perkotaan akan meningkatkan kebutuhan air bersih. Salah satu sumber air bersih adalah air tanah. Peranan air tanah semakin lama semakin penting karena air tanah menjadi sumber utama air untuk memenuhi kebutuhan pokok hajat hidup orang banyak seperti air minum, rumah tangga, industri, irigasi, perkotaan, dan lain-lain (Zeffitni, 2012). Salah satu pemanfaatan air tanah sebagai sumber air minum adalah penggunaan air sumur. Oleh karena itu, air sumur harus memenuhi parameter kualitas air minum seperti kandungan nitrit dan nitrat. Senyawa nitrogen (nitrit, nitrat dan amonia) di perairan secara alami berasal dari metabolisme organisme perairan dan dekomposisi bahan-bahan organik oleh bakteri (Indrayani dkk., 2015). Selain itu, nitrit dan nitrat di alam dapat dihasilkan secara alami maupun dari aktivitas manusia. Sumber alami nitrit dan nitrat adalah siklus nitrogen sedangkan sumber dari aktivitas manusia berasal dari penggunaan pupuk nitrogen, limbah industri dan limbah organik manusia. Pembentukan nitrit dan nitrat pada siklus nitrogen terjadi melalui proses fiksasi nitrogen oleh bakteri Rhizobium, nitrifikasi dan dinitrifikasi oleh bakteri Pseudomonas denitrifican. Nitritifikasi melibatkan dua proses yaitu nitritasi oleh bakteri Nitrosomonas dan nitratasi oleh bakteri Nitrobacter. Pada kondisi anaerob, nitrat adalah bentuk nitrogen yang cukup stabil tetapi dapat direduksi menjadi nitrit melalui proses nitratasi (Rosca dkk., 2009).

An ester of butanediol-alginate has been studied as a possible hemodialysis membrane. With 1,4-butanediol molar ratio of 0.1, 0.5, and 1.0, it showed that the membrane mechanical properties, stability, protein adsorption, platelet adhesion and performance for urea and creatinine clearance are better than that of unmodified alginate. The increase in 1,4-butanediol molar ratio causes hemodialysis ratio to improve, and causes protein adsorption and platelet adhesion at the membrane surface to decrease. In the case of protein adsorption and platelet adhesion, the membrane with the molar ratio of 1.0 has better hemocompatibility properties. In the hemodialysis test for 4 h, using 2.742 mg cm-2 h-1 of urea and 0.058 mg cm-2 h-1 of creatinine flux, this membrane showed that 48.5% of urea and 44.2% of creatinine were cleaned. ABSTRAK Ester butanadiol-alginat telah dipelajari mengenai kemungkinannya sebagai membran hemodialisis. Pada rasio mol 1,4-butanadiol:monomer alginat 0,1; 0,5; dan 1,0 menunjukkan bahwa kekuatan mekanik, stabilitas, adsorpsi protein, pelekatan trombosit dan kinerja klirens urea dan kreatinin membran lebih baik daripada alginat tanpa modifikasi. Peningkatan rasio mol 1,4-butanadiol menyebabkan peningkatan rasio hemolisis dan penurunan adsorpsi protein dan pelekatan trombosit pada permukaan membran. Membran dengan rasio mol 1,0 menunjukkan adsorpsi protein dan pelekatan trombosit yang rendah sebagai indikasi hemokompatibilitas yang lebih baik. Pada uji simulasi dialisis selama 4 jam, membran ini mampu mengurangi konsentrasi urea 48,5% dan kreatinin 33,2%, dengan fluks urea dan kreatinin masing-masing 2,74 dan 0,058 mg cm-2 jam-1. Kata Kunci: Ester butanadiol-alginat; membran hemodialisis; hemokompatibilitas

Synthetic humin, a new kind of adsorbents, has been synthesized and the adsorption of glucose on synthetic humin has been performed. The starting compound was obtained by leaching synthetic humus, which has been made by mixing biochar and hydrochar, by solution of 0.5 M NaOH. The effects of contact time, initial glucose concentration and pH on the adsorption process were studied through batch experiment. After adsorption, the residual glucose concentration was measured by UV-visible spectrometry using Nelson-Somogyi method. Results show that the synthetic humin can adsorp100 ppm glucose concentration completely at 48 h. Both the Langmuir and Freundlich models have analyzed the adsorption isotherm. However, the adsorption data were best fitted to the Freundlich isotherm with K value 0.00478 mg g^sup -1^. The adsorption of glucose by humin follows Ho's pseudo-second order kinetic model. It was found that the adsorption capacity of humin was 4.8 mg g^sup -1^ with rate constant of 8.42 × 10^sup -5^ g mg^sup -1^ min^sup -1^.

Abstrak Penelitian ini bertujuan untuk mengembangkan metode analisis kreatinin. Metode yang sering digunakan untuk analisis kreatinin secara spektrofotometri adalah dengan menggunakan Jaffe reaction yaitu mereaksikan kreatinin dengan asam pikrat sehingga menghasilkan senyawa kompleks yang dapat dianalisis dengan menggunakan spektrofotometri UV Vis dalam pelarut air. Pengembangan metode analisis kreatinin dilakukan dengan menambahkanTri octylmethylammoniumchloride (TOMAC) dalam pelarut kloroformsehingga membentuk pasangan ion asam pikrat-kreatinin-TOMA. Larutan organik kemudian dipisahkan dari larutan sampel dan selanjutnya dianalisis dengan menggunakan spektrofotometer UV Vis. Hasil penelitian menunjukkan bahwa uji validasi metode analisis kreatinin dengan menggunakan TOMA memiliki kelinearitas 98%, limit deteksi 1.089 ppm, SENScal 0.0107, SENSanal 1.089, dan presisi 0.3705. Abstract This research has been conducted to develop an analysis method of creatinine. The Jaffe reaction is a common method used to analyze creatinine by spectrophotometry. In this method, creatinine is reacted with the picric acid in aqueous solution to produce a complex compound which can be analyzed by spectrophotometer UV-Vis. The method development of creatinine analysis was conducted by adding Tri octyl methylammonium chloride (TOMAC) in chloroform to produce the ion pair of picric acid-creatinine-TOMA. The chloroform was extracted from the solution and then analyzed by spectrophotometer UV-Vis. The result showed that the method validation of creatinine analysis using TOMA as a co ionic-pair had the linearity of 98%, detection limit of 1,089 ppm, SENScal 0,0107, SENSanal 1,089 and precision 0,3705. Ginjal (renal) merupakan salah satu bagian organ manusia yang penting karena fungsi dari ginjal adalah menyaring limbah hasil metabolisme tubuh dan nantinya akan dibuang bersamaan dengan urine. Salah satu asam organik yang ditemukan dalam jaringan otot adalah kreatin (BM = 113,12 g/mol) dan salah satu hasil metabolismenya adalah kreatinin.

Metode analisis nitrit dan nitrat perlu dikembangkan untuk memonitor kualitas air minum. Kualitas air sumur untuk parameter nitrit dan nitrat dipengaruhi oleh kondisi lingkungan dan kedalaman air sumur. Penelitian ini bertujuan menganalisis nitrit dan nitrat menggunakan asam p-aminobenzoat (PABA) pada air sumur di daerah perkotaan Yogyakarta. Analisis nitrit didasarkan pada reaksi antara ion nitrit dengan PABA yang membentuk senyawa azo dengan panjang gelombang maksimum 546 nm. Kedalaman air sumur di daerah Catur Tunggal rata-rata > 10 m. Kadar nitrit dan nitrat pada air sumur adalah 0,05-0,09 dan 8,22-36,58 mg/L. Kadar nitrit dan nitrat tersebut memenuhi baku mutu dan aman untuk dikonsumsi. Konsentrasi nitrit dan nitrat pada air RO adalah 0,05 dan 2,72-59,57 mg/L. Kadar nitrit pada air RO tidak memenuhi baku mutu sedangkan kadar nitrat memenuhi baku mutu kecuali RO 5. Kata kunci: air sumur, asam p-aminobenzoat, kualitas air minum, nitrat, nitrit. Abstract The method for analysis nitrite and nitrate had to developed to monitor the drinking water quality. The well water quality, especially for nitrite and nitrate were influenced by environmental conditions and depth of well. This study aims to analyze nitrite and nitrate using p-aminobenzoic acid (PABA) in ground water at urban areas of Yogyakarta. The analysis was based on the reaction between nitrite ions with PABA which form azo compounds with a maximum wavelength of 546 nm. The depth of wells at Catur Tunggal were more than 10 m. Concentration of nitrite and nitrate in well water were 0.05 to 0.09 and 8.22 to 36.58 mg / L. The concentrations met the standard for drinking water quality and was safe for consumption. The concentration of nitrite and nitrate in reverse osmosis (RO) water were 0.05 and 2.72 to 59.57 mg / L. The concentration of nitrite did not meet the standard for drinking water quality while the concentration of nitrate met the standard for drinking water quality except RO 5. PENDAHULUAN Peningkatan jumlah penduduk perkotaan akan meningkatkan kebutuhan air bersih. Salah satu sumber air bersih adalah air tanah. Peranan air tanah semakin lama semakin penting karena air tanah menjadi sumber utama air untuk memenuhi kebutuhan pokok hajat hidup orang banyak seperti air minum, rumah tangga, industri, irigasi, perkotaan, dan lain-lain (Zeffitni, 2012). Salah satu pemanfaatan air tanah sebagai sumber air minum adalah penggunaan air sumur. Oleh karena itu, air sumur harus memenuhi parameter kualitas air minum seperti kandungan nitrit dan nitrat. Senyawa nitrogen (nitrit, nitrat dan amonia) di perairan secara alami berasal dari metabolisme organisme perairan dan dekomposisi bahan-bahan organik oleh bakteri (Indrayani dkk., 2015). Selain itu, nitrit dan nitrat di alam dapat dihasilkan secara alami maupun dari aktivitas manusia. Sumber alami nitrit dan nitrat adalah siklus nitrogen sedangkan sumber dari aktivitas manusia berasal dari penggunaan pupuk nitrogen, limbah industri dan limbah organik manusia. Pembentukan nitrit dan nitrat pada siklus nitrogen terjadi melalui proses fiksasi nitrogen oleh bakteri Rhizobium, nitrifikasi dan dinitrifikasi oleh bakteri Pseudomonas denitrifican. Nitritifikasi melibatkan dua proses yaitu nitritasi oleh bakteri Nitrosomonas dan nitratasi oleh bakteri Nitrobacter. Pada kondisi anaerob, nitrat adalah bentuk nitrogen yang cukup stabil tetapi dapat direduksi menjadi nitrit melalui proses nitratasi (Rosca dkk., 2009).