Qualified and preserved water is declining due to metal, waste, and hazardous chemicals contamination. Demand on fresh water raises and leads to the efforts on processing waste water with effective and efficient technology. Microbubble generator technology developed lately to result dissolved oxygen for raising microorganisms to decompose waste in waste water. This research used porous-ventury microbubble generator with 30° inlet angle and 20° outlet angle, placed in the center of 280 cm x 60 cm x 40 cm aquarium for experiment. This research aimed to find out bubble distribution and microbubble generator (MBG) performance. Measurement on bubble distribution conducted using Phantom Control Camera. Obtained data analyzed using MATLAB R2016a, while MBG performance measured using pressure transducer. Analysis conducted on variations of gas debit (0,1 lpm; 0,4 lpm., and 1 lpm) and water debit (30- 80 lpm) effects toward performance parameters, such as hydraulic power (Lw) and bubble generating efficiency (ηB). Results show that the greatest microbubbles’ diameter is 150- 500 μm, hydraulic power (Lw) increases with the inclining water debit (QL), effect of gas debit variation exert low effect towards Lw, and declining number of bubble generating efficiency (ηB) parameter with the inclining number of the water debit (QL).

The increasing demand for energy due to population growth and reduced sources of oil reserves puts pressure on every country to immediately produce and use renewable energy as a substitute, one of the alternative energy sources is biogas. The bacteria used in making this biogas is EM4, researchers used these bacteria because they can balance microorganisms. Microorganism inoculants consisting of 90% Lactobacillus produce cow dung are accommodated in a container made of HDPE plastic. The dimensions of the reservoir are 1 m3. Data collection was carried out starting from the first day to the fourteenth day. Retrieval of pressure data using a pressure gauge, temperature data retrieval using a thermometer gun and measuring the volume of biogas using an Arduino-based flow meter. From this study, it was found that biogas storage using HDPE polymer material with a size of 1x1 meters can accommodate a maximum biogas volume of 208.12 litres. In the non-continuous system, the volume of biogas produced is not stable with the total volume of biogas before going through the filter for 14 days is 1075.12 litres with an average volume of 76.79 litres/day while the total volume of biogas that has been through the filter for 14 days is 995.71 litres with an average volume of 71.12 litres/day.

Biogas is a raw material utilized to produced biogas. Biogas is renewable energy source produced by the anaerobic activity of organic matter through the fermentation process. Quality of biogas is determined by its main composition, such as methane (CH4). In addition, the composition of biogas also contains impurities such as unburnt carbon dioxide (CO2) so that it reduces the heating value, hydrogen sulfide (H2S) and water vapor (H2O) which are corrosive as well as Nitrogen (N2). Adsorption method on the impurity compositions can be used to improve biogas quality. This research used a column purifier containing four adsorbents in the form of calcium hydroxide Ca(OH)2, iron gram (Fe2(O3)), zeolite and activated carbon with three volume variations 600 cm3, 900 cm3 and 1200 cm3. The results of biogas testing using gas chromatography showed that the best quality obtained from the 1200 cm3 volume of adsorbent. Methane content was increased up to 17.985% and the impurity gases were decreased, such as carbon dioxide in as much as 18.15%, hydrogen sulfide and water vapor in as much as 0.182%. The heat produced by unpurified biogas was 1518.312 kJ/m3 and the highest heating value after purification was 2108.22 kJ/m3. The biogas combustion resulted in a dominant blue flame color.The most optimum effectiveness of the technology resulted in an increase of the methane content up to 64.275%. Based on this research, the utilization of column purifier with the adsorption method was able to improve the quality of biogas

Menipisnya cadangan sumber minyak bumi di Indonesia dapat menjadi penghambat pembangunan pertanian berkelanjutan. Potensi energi alternatif salah satunya adalah limbah biomassa tongkol jagung yang dihasilkan dari aktivitas produksi pertanian yang jumlahnya sangat besar. Tongkol jagung memiliki nilai kalor sebesar 4059.853 kal/gr sehingga semakin banyaknya tongkol jagung yang digunakan akan mempercepat proses pembakaran. Akan tetapi proses pembakaran yang dilakukan harus dibantu oleh serbuk kayu kering sebagai pemantik bagi api. Kayu kering yang memiliki nilai kalor lebih besar dari tongkol jagung akan terbakar lebih cepat dan membantu membakar tongkol jagung. Hasil dari nyala lampu terdapat pada massa tongkol jagung 400gr dengan variasi volume air 250ml menyala redup selama 1 menit. Pada massa 500gr lampu menyala redup selama 1 menit pada variasi volume air 150ml dan 200ml. Sedangkan lampu menyala terang selama 20 detik pada variasi 250ml air. Hal ini juga membuktikan bahwa banyaknya volume air yang digunakan dapat mempengaruhi nyala lampu.