INVESTIGATION OF MICRO BUBBLE FOR THE REMOVAL OF SUSPENDED PARTICLE AND ENHANCEMENT OF DISSOLVED OXYGEN IN POLLUTED WATER

Filtration and precipitation are generally used in wastewater treatment to separate pollutants. However, they are not cost effective and have problems of filter waste and time consumption. The smaller particles are left even after a filtration process, depending upon the porosity of the filter. This research proposes a new approach of using compressed air to lift up micro suspended particles in polluted water. The novelty of the approach is in its sustainability, cost effectiveness and faster solution to micro pollutant separation. Air is forced through a submerged micro diffuser to produce micro bubbles, which flow upward and entrain suspended particles to separate them from water. The study was carried experimentally and a lab test rig was designed and implemented. Bubble size plays an important role in moving suspended particles upwards due to the buoyancy force, which in turn depends upon the vertical component of bubble velocity. Generally, the larger bubbles tend to change shape due to high buoyancy force. The bubble velocity is characterized by the Froude number and Reynolds number. The strategies to control the bubble size in monodispersed (single size) and polydispersed (multi size) cases are presented in this research. To simulate the real wastewater physiochemical characteristics (surface tension, density, viscosity, etc), Glycerin is added to distilled water in various volume fractions of 0.1% to 0.5%. The relationship between air pressure, vertical and horizontal velocities, as well as bubble size is studied. These parameters (bubble diameter, vertical velocity) lead to high effectiveness of suspended particles separation, and are validated by measuring the low concentration of pollutant (PPM), corresponding to the turbidity level. The amount of suspended particles in relation to turbidity has been studied and it is found that the turbidity level of 6.9 NTU decreases to 3.66 NTU, using 1-10 micron porous sintered glass as a submerged diffuser and at 12 10-3 m3/min air flow. In most biological wastewater treatment systems, a submerged diffuser is used to provide oxygen and mixing to degrade the organic matter. In this study, the effectiveness of micro diffusers in the degradation of organic matter was investigated. The nitrification performance using both micro and macro diffusers was evaluated by measuring ammonium-nitrogen (NH4-N) and nitrate-nitrogen (NO3-N). The experimental values were compared with the theoretical values derived from the kinetic calculations. Two batch experiments were conducted for the estimation of the kinetic parameters for the degradation and the nitrification of organic matter at 1 hour, 3 hours, 6 hours, and 24 hours until 48 hours, in steps of 3 hours for each batch of experiments. From the measurement results, the degradation kinetic COD parameter (kCOD) of the micro diffuser was found to be 1.46 times higher than the macro diffuser. Therefore the degradation kinetics of soluble COD parameter (ksCOD) of the micro diffuser was found to be 1.5 times higher than macro diffuser. The difference between micro and millimeter diffusers in removed COD was approximately 6%. , and in removed sCOD was approximately 16%. The main data parameters in Nitrification of wastewater were ammonium and nitrate. The measurement results of ammonium and nitrate using micro diffuser was achieved at 3% higher than macro diffuser

INVESTIGATION OF MICRO BUBBLE FOR THE REMOVAL OF SUSPENDED PARTICLE AND ENHANCEMENT OF DISSOLVED OXYGEN IN POLLUTED WATER

Filtration and precipitation are generally used in wastewater treatment to separate pollutants. However, they are not cost effective and have problems of filter waste and time consumption. The smaller particles are left even after a filtration process, depending upon the porosity of the filter. This research proposes a new approach of using compressed air to lift up micro suspended particles in polluted water. The novelty of the approach is in its sustainability, cost effectiveness and faster solution to micro pollutant separation. Air is forced through a submerged micro diffuser to produce micro bubbles, which flow upward and entrain suspended particles to separate them from water. The study was carried experimentally and a lab test rig was designed and implemented. Bubble size plays an important role in moving suspended particles upwards due to the buoyancy force, which in turn depends upon the vertical component of bubble velocity. Generally, the larger bubbles tend to change shape due to high buoyancy force. The bubble velocity is characterized by the Froude number and Reynolds number. The strategies to control the bubble size in monodispersed (single size) and polydispersed (multi size) cases are presented in this research. To simulate the real wastewater physiochemical characteristics (surface tension, density, viscosity, etc), Glycerin is added to distilled water in various volume fractions of 0.1% to 0.5%. The relationship between air pressure, vertical and horizontal velocities, as well as bubble size is studied. These parameters (bubble diameter, vertical velocity) lead to high effectiveness of suspended particles separation, and are validated by measuring the low concentration of pollutant (PPM), corresponding to the turbidity level. The amount of suspended particles in relation to turbidity has been studied and it is found that the turbidity level of 6.9 NTU decreases to 3.66 NTU, using 1-10 micron porous sintered glass as a submerged diffuser and at 12 10-3 m3/min air flow. In most biological wastewater treatment systems, a submerged diffuser is used to provide oxygen and mixing to degrade the organic matter. In this study, the effectiveness of micro diffusers in the degradation of organic matter was investigated. The nitrification performance using both micro and macro diffusers was evaluated by measuring ammonium-nitrogen (NH4-N) and nitrate-nitrogen (NO3-N). The experimental values were compared with the theoretical values derived from the kinetic calculations. Two batch experiments were conducted for the estimation of the kinetic parameters for the degradation and the nitrification of organic matter at 1 hour, 3 hours, 6 hours, and 24 hours until 48 hours, in steps of 3 hours for each batch of experiments. From the measurement results, the degradation kinetic COD parameter (kCOD) of the micro diffuser was found to be 1.46 times higher than the macro diffuser. Therefore the degradation kinetics of soluble COD parameter (ksCOD) of the micro diffuser was found to be 1.5 times higher than macro diffuser. The difference between micro and millimeter diffusers in removed COD was approximately 6%. , and in removed sCOD was approximately 16%. The main data parameters in Nitrification of wastewater were ammonium and nitrate. The measurement results of ammonium and nitrate using micro diffuser was achieved at 3% higher than macro diffuser

SMALL-HOLE DRILLING USING DIE SINKER ELECTRICAL DISCHARGE MACHINE

Banyak kesulitan dihadapi pada pemesinan lubang kecil. Terutama jika prosesnya dilakukan dengan proses drilling mekanik. Untuk mengatasi kendala yang dihadapi, proses pemesinan non-tradisional seringkali diterapkan. Tulisan ini melaporkan hasil studi pemesinan lubang kecil (diameter kurang dari 1 mm) menggunakan EDM die sinker. Lubang dibuat pada aluminium dengan ketebalan 3 mm. Kawat tembaga berdiameter kurang dari 1 mm dipergunakan sebagai elektroda. Untuk menghindari keausan elektroda yang berlebihan, pemesinan dilakukan dengan menggunakan parameter yang menghasilkan energi rendah. Pemilihan parameter ini juga dimaksudkan untuk mendapatkan kualitas lubang yang baik. Pengamatan dilakukan terhadap kualitas lubang yang dihasilkan. Selain itu studi juga dilakukan pada pengaruh parameter pemesinan terhadap keausan elektroda dan waktu pemesinan. Hasil studi menunjukkan bahwa lubang dengan diameter kurang dari 1 mm berhasil dibuat dengan mesin EDM die sinker. Waktu yang diperlukan untuk pemesinan berkisar antara 5 – 6 menit. Lubang yang dihasilkan memiliki kebulatan yang relative baik dan permukaan yang tajam. Peningkatan energi pemesinan menambah keausan elektroda dan memperpanjang waktu pemesinan.   Keywords: EDM, small hole, drilling, electrode wea

PENGEMBANGAN UNIT PENSUPLAI DAYA BERTENAGA SURYA UNTUK POMPA AIR KELOMPOK TERNAK SAPI DI DAERAH PEDESAAN

In farming, clean water is a basic need to wash food, drink, bathe and clean the cow shed. Provision of clean water is by means of an electric water pump. Meanwhile, electricity prices tend to rise gradually, consequently monthly the electricity bill for farming needs rise. Another thing, the power outage in the countryside sometimes happens in a long duration. The stability of clean water availability at the location of livestock groups is disrupted. One of the best solution approaches to overcome these problems is to create and develop applied pro-ducts related to renewable energy and energy independence, namely solar power supply unit. This power supply unit uses 2 150WP 12 Volt solar panels, 2 solar charge controllers, 3 100Ah batteries and a DC to AC 1500W inverter. The result of the development of this solar powered power supply unit is about 300 Watt. Its main function is to turn on the water pump during the day and in addition it is able to turn on the led light for street lighting at night. Based on the observations, this unit has been operating well and effectively for about 1 month and successfully assisted members of the cow farm groups in the provision of clean water

Nitrification using submerged micro bubbles diffuser in an aeration system

The objectives of this research are to evaluate the effectiveness of the micro- diffuser in enhancing nitrification in wastewater treatment. The nitrification performances of micro- and milli- diffusers were evaluated by measuring NH4-N and NO3-N contents. The experimental values were also compared with the theoretical values derived from the kinetic calculations. Two reactors A and B, of size 140x140x500 mm were constructed using perspex to treat municipal wastewater. Aeration in the reactors A and B was provided using millimeter diffuser and micro diffuser, respectively. The diffusers consisted of perforated aluminium plate to generate millimeter bubbles and sintered porous glass to generate micro bubbles. Compressed air was forced through two parallel flow meters at a flow rate of 2.5 L/min. Biomass for both reactors was acclimatized prior to treating the municipal wastewater in the reactors. Two batch experiments were conducted at 26°C for the biological study and in the estimation of the kinetic parameters for the nitrification. Samplings were conducted at 1 hour, 3 hours, and every 6 hours respectively, until 48 hours for each batch of the experiment. The main parameters tested were NH4-N and NO3-N. The results of the study indicated that ammonia-nitrogen removal was achieved at 90% and 87%, for the micro- and milli- diffusers, respectively. The final average ammonia-nitrogen removal rate was found to be 0.48 mg/L.hr and 0.28 mg/L.hr, for micro and milli diffuser, respectively. The experimental degradation rate also closely follows the theoretical degradation rate with the theoretical degradation rate from 36-48 hrs. of aeration found to be 0.5 mg/L.hr and 0.46 mg/L.hr for micro and milli diffuser, respectively. It can be concluded that the use of micro diffuser can provide higher ammonia-nitrogen removal from wastewater. Keywords: Millimeter diffuser; micro diffuser; NH4-N removal;, NO3–N production; kinetics evaluatio

UNJUKKERJATURBIN ANGIN SUMBU VERTlKAL TIPE HYBRIDANTARA SAVONIUS DAN DARRIEUS DENGAN VARIASI JUMLAH SUDU

intisari-Dengan memadukan turbin angin sumbu vertikaltipe Savonius dan Darrieus, akan didapat suatu turbin angin hibrid yang ringan padastart awal dan effisien dalam menghasilkan tenaga listrik. Savonius merupakan tipe turbin angin yang bekerja berdasar- kan gaya drag dengan ciri yang bisa starting pada kondisi kecepatan rendah namun efisiensinya rendah. Sedangkan tipe Darrieus merupakan tipe turbin angin yang mempunyai efisiensi tinggi namun starting awal pada kondisi kecepatan angin rendah lebih sulit.Dalam penelitian ini dilakukan dengan cara membandingkan unjuk kerja Turbin hibrid dengan jenis generator untuk putaran rendah. Sudu turbin angin Savious sebagai starting pada kecepatan angin yang rendah akan divariasikan dengan jumlah bilah 2 dan 3. Sedang tipe Darrieus menggunakan sudu tipe H berjumlah tiga, empat atau lebih, sebagai penghasil tenaga listrik yang effisien. Mini generator digunakan alternator sepeda Iistrik yang telah dimodifikasi untuk mengkon- versiputaran turbin menjadi listrik yang lebih effisien. Hasil modifikasial ternator/generator menunjukkan unjuk kerja yang lebih bag us diban-dingkan dengan penelitian sebelumnya (tahun 2014). Pengukuran ini dilakukan di laboratorium dengan kecepatan angin yang rendah dari blower. Untuk putaran 900 rpm tegangan yang mampu dibangkitkan adalah 2 - 7 VAC dengan arus sebesar 0,4 A. Hasil modifikasi generator ini lebih bagus dari penelitian sebelumnya yaitu tegangan 4 VAC dengan arus sebesar 0,1 A

A novel approach of micro-pollutant separation in a stagnant water column

Filtration and precipitation are generally used in waste water treatment to separate pollutants. However, they are not cost effective and have problems of filter waste and time consumption. This research proposes a new approach using compressed air to lift-up micro suspended particles in wastewater treatment. The novelty of the approach is its sustainability, robustness, and cost effectiveness in micro pollutant separation. Air is forced through submerged nano diffuser to produce micro bubbles, which flow upward and lift-up suspended particles to separate them from water. A lab scale stagnant water column (100mm W x 100mm L x 240 mm H) is used in this micro pollutant separation process. Submerged sintered glass modules with porosities ranging from 1 to 40 microns are used to study the effect of air pressure and flow on the size of bubbles. The Phase Doppler Anemometry (PDA) is used to measure the bubble velocity (horizontal and vertical) and its diameter. Various forces that act on the bubble during its detachment from the micro diffuser are established and correlations for the forces acting on the particle-bubble system have been developed for different particle to bubble diameter ratios. Effects of air flow through diffuser, inlet air pressure and various porosities on bubble size are presented in this paper. The bubble velocity is characterized by Froude number and Reynolds number. The amount of suspended particles in relation to turbidity has also been investigated and found that the turbidity level of 6.9 NTU decreases to 3.66 NTU, using 1-10 micron porous sintered glass at 0.2 l/min air flow. Keywords: micro bubble, suspended particle lift-up, Froude number, porous sintered glass diffuser, Turbidity

Potensi Pembangkitan listrik hybrid menggunakan vertical axis wind turbine tipe Savonius dan panel surya

The use of fossil energy for conventional power plants in the long time will run out oil, gas and coal reservoir. Therefore the renewable energy utilization that more environmentally friendly and renewable concepts such as wind and solar heat should be optimized. Two kind of potensial renewable energy resources in Indonesia that should be optimized are wind power and solar energies, They will be complement each other, in the dry season the sun will be role while in the rainy season wind power will be more dominant. This hybrid concept combining solar cell panels and Savonius turbine to gain a greater electrical output than the solar cell panels and Savonius wind turbine that operate in their owntask. A single stage Savonius wind turbines are made three design types to find the best design that can convert more energy from any wind direction. A Solar cell panel is placed under the sun to produce current and voltage from sun light. The energy summation data will be recorded by Data Aquisition System. From the measurement and data analysis results, the electrical power generated by prototype of hibrid system is 7.5 watt. This value is greater if compare to the power generated by solar panelsand wind turbines separatelly

Pengaruh Sistem Minimum Lubrication dengan Metoda Tetesan terhadap Keausan Pahat dan Kekasaran Permukaan Benda Kerja AISI 4340

Intisari Saat ini telah dikembangkan teknik pendinginan yang baru yaitu Minimum Quantity Lubrication (MQL), dimana 50-500 ml/jam lubricant disemprotkan ke arah sisi kontak antara pahat dengan benda kerja. Keberadaan lubricant sebagai pelumas dapat mengurangi gaya gesek antara pahat dengan benda kerja, sehingga umur pahat dapat diperpanjang. Pada penelitian ini akan dikembangkan teknik lubrikasi minimal yaitu dengan metode tctcsan. Penelitian ini mcnggunakan empat metode pen• dinginan pahat yaitu: wet, dry, MQL, dan tetesan. Ester oil digunakan sebagai media lubrikasi pada penelitian ini. Pcngujian mcnggunakan mcsin Lathe CNC Dcnford Cyclone P, dcngan insert carbide PLANSEE TIZIT DCMT 11T304EN-SM. Nosel diarahkan pada sisi flank pahat bubut. Selama pcmbubutan dilakukan perekaman foto flank wear (VB). Pembubutan dilakukan hingga tercapai lebar flank wear 0.3 mm. Hasil dari pengujian ini menunjukkan teknik tetesan dapat meningkatkan umur pahat dan memperbaiki kekasaran permukaan benda kerja dibandingkan teknik wet ataupun dry. Teknik tetesan dalam hal umur pahat masih di bawah teknik MQL, tetapi teknik tetesan ini lebih sederhana jika dibanding teknik MQL, karena tidak memerlukan kompresor sebagai penyalur lubricant bertekanan. Keywords- MQL, lubricant.flank wear, tetesan

Perancangan Generator Magnet Permanen Flux Aksial untuk Aplikasi Turbin Angin Vertikal

The usage of wind energy problem in Indonesian is the low winds speed character. The applied of horizontal axis wind turbine has not reached at maximum contribution of energy recovery as an alternative energy. Therefore it needs a new strategic for low winds speed converting into maximal benefits electric energy. The application of Vertical Axis Wind Turbine (VAWT) as an alteration of Horizontal Axis Wind Turbine (HAWT) is estimated to cover the low wind speed condition, because this turbine type can catch wind in all direction, however the disadvantage is low effisiensi. Therefore the suitable generator should be used. The suitable generator is multipole type that can be found in an axial fluxs generator. The application of axial fluxs permanent magnet generator conect with VAWT hoppely can answer the problem in wind energy converting in Indonesian, with the result that effisien and relay on alternative electric energy employing