Cultivation of Chlorella vulgaris Using Different Sources of Carbon and Its Impact on Lipid Production

A cultivation process of Chlorella vulgaris has been done in different treatment to investigate the optimum condition for lipid production. Firstly, autotroph and heterotroph condition have been applied to test the significance impact of carbon availability to the growth and lipid production of Chlorella vulgaris. And for the same purpose, heterotroph condition using glucose, fructose and sucrose as carbon sources was independently implemented. The growth rate of Chlorella vulgaris in autotroph condition was much slower than those in heterotroph. The different sources of carbon gave no significant different in the growth pattern, but in term of lipid production it was presented a considerable result. At lower concentration (3 and 6 gr/L) of carbon sources there was only slight different in lipid production level. At higher concentration (12 gr/L) glucose as a carbon source produced the highest result, 60.18% (w/w) compared to fructose and sucrose that produced 27.34% (w/w) and 18.19% (w/w) respectively

Optimasi Sintesa Biodiesel Dari Mikroalga Scenedesmus dimorphus Melalui Reaksi Transesterifikasi In Situ

Mikroalga merupakan bahan baku yang sangat potensial untuk dikembangkan menjadi biodiesel atau metil ester karena memiliki kandungan minyak yang tinggi. Salah satu mikroalga yang bisa dikembangkan untuk sintesa biodiesel adalah alga Scenedesmus dimorphus. Biodiesel merupakan bahan bakar alternatif yang bisa menggantikan minyak diesel/solar yang dihasilkan dari minyak bumi. Pada penelitian ini, metode response surface digunakan untuk menentukan kondisi operasi yang optimum pada sintesa biodiesel dari Scenedesmus dimorphus melalui reaksi transesterifikasi in situ. Pengaruh variabel input suhu dan waktu reaksi terhadap yield metil ester dipelajari dan kondisi optimum ditunjukkan oleh nilai yield metil ester yang maksimum. Reaksi transesterifikasi dilakukan di dalam reaktor batch. Central composite design dengan dua variabel input dan sebagai response adalah yield metil ester digunakan untuk mempelajari pengaruh variabel input suhu dan waktu reaksi. Hasil penelitian menunjukkan bahwa yield metil ester meningkat dengan kenaikan suhu dan waktu reaksi sampai mencapai titik optimum kemudian turun. Kondisi operasi untuk reaksi transesterifikasi in situ yang optimum adalah suhu reaksi 46oC dan waktu reaksi 5 jam

Effect of Manganese Coating on the Sorption Performance of Pyrolusite for Lead in Aqueous Conditions

A process to modify the property of pyrolusite, a natural form of manganese dioxide, was done in order to get a better adsorption performance. Modification was executed by coating the mineral with manganese solution (KMnO4, 0.05 M). Characterization analysis with XRF described significant change on Mn and MnO components, which was higher on the coated material compared to the ore. Meanwhile, although has not perfectly homogenous, it was identified that the distribution of pore diameter reduced from 2.23 – 4.08 µm to 0.65 – 1.07 µm. Another important result from this study was that pHpzc of pyrolusite shifted from 4.2 to 1.9, giving a wider range on pH working solution for the adsorption performance. Manganese coated pyrolusite performed very well in 4 different pH conditions, providing overall removal efficiency above 90% for Lead. Furthermore, from a series of adsorption batch experiments it has been known that the adsorption mechanism of modified pyrolusite for Lead was better explained with Langmuir equation and the kinetics reaction was best modelled by pseudo-second order

Kinerja Bentonit Terinterkalasi HDTMA dan Komposit Bentonit Kitosan Sebagai Adsorben Untuk Fenol dan Metilen Biru

Serangkaian proses modifikasi bentonit telah dilakukan untuk mendapatkan bentonit terinterkalasi HDTMA dan komposit bentonit-kitosan. Kedua bahan diaplikasikan sebagai adsorben metilen biru dan fenol. Larutan surfaktan HDTMA~Cl I o/c dan suspensi bentonit disiapkan dengan rasio bentonit/air 20g/IOOmL melalui proses pengaturan pH, pemanasan, pengendapan, dan pencucian. Sebanyak 5 g bentonit tersebut dicampur dengan 1% v/v asam asetat dan ditambahkan kitosan yang sudah dideasetilasi. Setelah diaduk 12 jam, campuran tersebut dicuci, disaring, dan dikeringkan. Adsorbat fenol dan biru metilen disiapkan sebagai larutan stok dari pengenceran larutan induk fenol dan biru metilen dengan akuades. Larutan umpan dari stok dibuat sesuai konsentrasi yang dikehendaki. Percobaan dilakukan secara batch dengan kolom adsorpsi OMNIFIT. Aliran dari kolom adsorpsi diresirkulasi ke tanki penampung. Laju larutan umpan dan banyaknya adsorben diatur konstan pada kecepatan 1 mL/menit. Konsentrasi awal fenol dan biru metilen divariasikan dari 10 hingga 250 mg/L. Sampling dilakukan setiap 5 menit pada 30 menit pertama, diikuti dengan tiap 15 menit, hingga sistem mencapai kondisi setimbang. Analisis sampel dilakukan dengan menggunakan spektrofotometer UV. Hasil penelitian menunjukkan bahwa komposit bentonit-kitosan memiliki kemampuan adsorpsi yang lebih besar, yaitu 65 mg/g dan 95 mglg untuk adsorbat fenol dan metilen biru. Sedangkan, bentonit terinterkalasi HDTMA memiliki kemampuan adsorpsi 35 mg/g untuk fenol dan 38 mg/g untuk metilen biru. Aplikasi model adsorpsi yang paling sesuai adalah model Freundlich. Model adsorbsi tersebut menjelaskan interaksi antara adsorben dan adsorbat dipengaruhi oleh reaksi fisik

Characterization of Food Waste from a Campus Canteen as Potential Feedstock for Biogas Production

Food waste collected from the Ubaya canteen was characterized for its potential for use as anaerobic feedstock. It was collected for 3 weeks on a daily basis and treated with 2 different pretreatments, i.e. mechanic and mechanic-thermal. The result showed that the physical and chemical properties of the food waste in the 3-week time period of collecting were not significantly different for both pretreatments. The VS/TS ratio was around 96.4% to 97.076% and C/N was in the range of 17.295 to 17.813 for the mechanic and mechanic-thermal treatments. Four semi-batch mesophilic anaerobic digesters were used in this study, with 1.215 gVS/L fed once (R1) and twice daily (R3); 2.43 gVS/L fed once (R2) and twice daily (R4). The maximum methane yield was determined to be 64.61 mL/gVS in R1 after 5 days of incubation and 57.41 mL/gVS in R3 after 4 days of incubation. Systems R2 and R4 showed maximum methane yields of 43.15 mL/gVS and 19.1 mL/gVS respectively

The role of C/N ratio on anaerobic decomposition of industrial tempeh wastewater for optimizing methane production

Considering its high organic contents, biological process, in particular anaerobically decomposition is considered to be the most suitable treatment for industrial tempeh wastewater. Among the important parameters that determine the success level of process, C/N ratio was mentioned to play significant role. Thus, this study was carried out to investigate the effect of different C/N ratio (10; 20; 30 and 40) to the process decomposition to produce methane gas. The experiment was conducted using 1L batch reactors with sludge from active cow manure biogas digester as inoculum. Several parameters such as pH, COD, BOD, VFAs and methane gas were monitored during the process in order to understand the mechanism. The experimental results confirmed that C/N ratio significantly affected the anaerobic decomposition of tempeh wastewater giving the best achievement for C/N = 30, with organic removal as high as 89% (COD) and total methane produced as much as 1240 mL in 14 days of observation. The balance composition between carbon and nitrogen is important for anaerobic process, higher organic loading (C/N = 40) will potentially lead to VFAs accumulation meanwhile higher nitrogen concentration (C/N = 10) will stimulate complex transition mainly denitrification and free ammonia formation. Both conditions will block the methanogenesis stage, resulting in non-optimal decomposition process and minimum methane production

Perancangan Natural Daylighting Pada Sustainable Plant Building

berkurang, limbah, krisis energi hingga kelangkaan air mulai menjadi perhatian dunia. Terkait dengan krisis energi, selain karena kelangkaan sumber daya, penggunaan energi yang tidak tepat dapat membebani perusahaan karena biaya operasional yang tinggi. PT. X adalah sebuah pabrik tutup panci di Sidoarjo. Salah satu fasilitas produksinya adalah unit kaca, menempati bangunan konvesional yang menjadi objek penelitian ini. PT. X dalam operasionalnya memanfaatkan penerangan dari lampu TL. Dari perhitungan electrical dan lightning system (Tompkins et al, 2003) diperkirakan jumlah lampu yang ada di dalam bangunan pabrik adalah 508 lampu. Berdasarkan analisis perhitungan fl dengan memanfaatkan software DIALux untuk mesimulasikan kebutuhan lampu pada masing-masing departemen, didapatkan hasil masih banyak departemen yang tidak memenuhi kebutuhan minimal penerangan. Pencahayaan buatan ini dapat dikurangi dan digantikan dengan pencahayaan alami, misalnya dengan menggunakan Solatube. Dari hasil rancangan, direkomendasikan untuk mengganti penggunaan lampu TL sebanyak 450 lampu. Penggunaan Solatube juga menghemat penggunaan energi listrik hingga 97% dan memiliki umur produk hingga 20 tahun

The use of pyrolusite to remove Pb and Cd in aqueous solutions : isotherm and thermodynamic

The utilization of natural material as an adsorbent to eliminate contaminants in the water is of great interest. Natural material can be directly used without further treatment that may lead to higher environmental impact. In this study, pyrolusite which is immensely available in Indonesia, especially in East Nusa Tenggara, were used to adsorb Cadmium (Cd) and Lead (Pb) in single and simultaneous condition. Several operational parameters such as initial concentration, pH and temperature were applied in order to elaborate the sorption mechanism and to determine the adsorption capacity. The amount of absorbed Cd and Pb were increased at a higher pH and reached the optimum condition at pH 7 for both. The adsorption isotherm for both adsorbate were best modeled following The Langmuir equation, giving an adsorption capacity as high as 108.70 mg/g and 123.45 mg/g for Cd and Pb respectively. Additionally, thermodynamics data showed that the adsorption process in this study was endothermic process

Adsorption Cadmium and Lead Onto Natural Manganese Dioxide

The utilization of natural material as an adsorbent to eliminate contaminants in the water is of great interest. Natural material can be directly used without further treatment which may lead to higher environmental impact. In this study, natural manganese dioxide (pyrolusite) which is immensely available in Indonesia, especially in East Nusa tenggara, were used to adsorb Cadmium (Cd) and Lead (Pb) in single and simultaneous condition. Several operational parameters such as initial concentration, pH and temperature were applied in order to elaborate the sorption mechanism and to determine the adsorption capacity. Meanwhile, simultaneous condition was set to identify the effect of coexistence ion on adsorption process. The amount of absorbed Cd and Pb were increased at a higher pH and reached the optimum condition at pH 7 for both. The adsorption isotherm for both adsorbate were best modeled following The Langmuir equation, giving an adsorption capacity as high as 108.70 mg/g and 123.45 mg/g for Cd and Pb respectively. Thermodynamics data showed that the adsorption process in this study was endothermic process. Additionally, in simultaneous condition, the presence of coexistence ion reduced the adsorbed amount of targetted ion. In this case the adsorption of Pb were less impacted compared to the adsorption of Cd

Adsorption of Phosphate in Aqueous Solutions Using Manganese Dioxide

Effort to remove phosphate from aquatic ecosystem is of great interest, not only for preventing algae bloom problem but also for recovering phosphate, as this is an essential material. Adsorption is considered as an effective method especially because the nutrient loaded adsorbent can be directly used for fertilizer. Therefore, this study investigated the potential use of manganese dioxide in natural form (pyrolusite) to adsorb phosphate in aqueous solutions. A series of batch experiments were done to elaborate the adsorption process of phosphate onto manganese dioxide. Several environmental conditions such as pH, temperature and ionic strength were applied in order to get a better understanding of the process mechanism. The results indicated that pH was obviously affected the adsorption process, meanwhile ionic strength did not play significant role. The adsorption of phosphate was higher at a lower pH and getting reduced as the pH increased. Similar to that, the percentage removal of phosphate was declined significantly in higher ionic strength, indicated that the interaction between phosphate and manganese dioxide was mainly controlled by electrostatic force.  The adsorption isotherm data correlated better with Langmuir model rather than Freundlich model. The maximum adsorption capacity of manganese dioxide was 11.40 mg P/g. The kinetic data was very well fitted to pseudo second order equation suggested that chemical reaction involved in adsorption process. Moreover, thermodynamic data confirmed that phosphate adsorption onto manganese dioxide was an endothermic process