Produksi padi akan menghasilkan limbah yang disebut sekam. Dari sekitar 100 kg tanaman padi kering hanya diperoleh beras 28,9 kg beras dengan 55,6 kg jerami dan 8,9 kilogram sekam serta 3,6 kg bekatul. Limbah sekam hingga sampai saat ini perlu dicari cara pemanfaatannya agar lebih bernilai ekonomis. Salah satu pemanfaatan sekam padi yang dapat dilakukan adalah dengan membuat sekam padi menjadi karbon aktif yang dapat digunakan sebagai bahan penyerap pada pengolahan air baku atau limbah cair industri agar limbah tersebut nantinya dinyatakan aman ketika dibuang ke lingkungan. Pembuatan karbon aktif dari sekam padi ini dilakukan melalui beberapa tahap. Tahap pertama dilakukan prosess karbonisasi pada suhu 400oC —600oC. Setelah proses karbonisasi, dilakukan pengecilan ukuran karbon untuk memperluas permukaan karbon. Tahap selanjutnya adalah proses aktivasi, di mana zat aktivator yang digunakan pada penelitian kali ini adalah kalium hidroksida dan asam fosfat dengan variasi konsentrasi 3M dan 9M. Proses aktivasi dilakukan pada temperatur 50oC dan 100oC selama 2 jam. Dari hasil penelitian didapatkan luas permukaan paling besar 130,31 mg/g dengan kondisi operasi aktivasi 50oC dengan menggunakan activator KOH.

ABSTRAK: Industri rumah tangga yang membuang banyak limbah deterjen adalah usaha laundry (binatu). Surfaktan memiliki sifat sebagai penurun tegangan permukaan. Di dalam badan air bisa menyebabkan busa yang bisa menyebabkan rasa gatal. Sebagai limbah rumah tangga, limbah laundry ini biasanya dibuang langsung ke lingkungan tanpa pengolahan, yang jika dibiarkan, tentu saja akan berdampak buruk bagi lingkungan. Kandungan dalam limbah cucian seperti COD, BOD, TDS, pH, tingkat fosfat dan kekeruhan yang tidak memenuhi standar kualitas dapat menyebabkan lingkungan yang tercemar dan dapat mengganggu kesehatan masyarakat dan lingkungan. Dalam penelitian ini, dua metode pengolahan air diterapkan, yaitu koagulasi dan elektrokoagulasi dengan menambahkan 7 ml 5% peroksida. Penelitian ini dilakukan dalam proses batch baik elektrokoagulasi dan koagulasi. Parameter yang ditinjau adalah COD, TSS, pH, tingkat fosfat, PO4dan kekeruhan. koagulasi menggunakan koagulan tawas (Aluminium sulfat). Variasi dari dua proses koagulasi adalah, untuk koagulasi, kecepatan pengadukan adalah 300 rpm selama 10 menit dan dosis koagulan (500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm dan 900 ppm). Dalam elektrokoagulasi, waktu kontak divariasikan (15 menit, 20 menit, 25 menit, 30 menit). Hasil terbaik yang diperoleh adalah pengolahan air limbah menggunakan metode eletrokoagulasi dengan penurunan COD 76%, BOD 83%, kekeruhan 98% dan fosfat 99,9%.ABSTRACT Problems with laundry waste, especially in the content of surfactants in detergents. Surfactants have properties as surface tension reducers. In the body of water can cause foam that can mediate itching. As domestic waste, this laundry waste is generally disposed directly to the environment without any treatment, which if left unchecked, of course, will be bad for the environment. The content in laundry wastes such as COD, BOD, TDS, pH, phosphate level and turbidity that do not comply with quality standards can cause polluted environments and can disrupt public health and the environment. In this study, two water treatment methods were applied, namely coagulation and electrocoagulation by adding 7 ml of 5% peroxide. This research was carried out in a batch process both electrocoagulation and coagulation. The parameters reviewed were COD, TSS, pH, phosphate level, PO4-and turbidity. Coagulation using alum coagulant (Aluminum sulfate). The variation of the two coagulation processes is, for coagulation, the stirring speed is 300 rpm for 10 minutes and the coagulant dose (500 ppm, 600 ppm, 700 ppm, 800 ppm and 900 ppm). In electrocoagulation contact times were varied (15 minutes, 20 minutes, 25 minutes, 30 minutes). The best results obtained were wastewater treatment using the Electrocoagulation method with a COD reduction of 76%, BOD 83%, turbidity 98% and phosphate 99.9%.

Abstract. Cu/ZnO catalyst was succesfully prepared using a coprecipitation method. The mixing procedure of the Cu(NO 3 ) 2 , Zn(NO 3 ) 2 and Na 2 CO 3 solutions had an important influence on the characteristics of the catalyst. The best catalyst obtained was the one prepared with slow mixing of the salt solutions and a CuO/ZnO molar ratio of 50:50. This raw catalyst had a maximum surface area of about 61.6 m 2 /g. Increasing the CuO/ZnO molar ratio caused an agglomeration of precipitated particles, reducing the surface area. A much better catalyst was obtained using an impregnation method, in which -Al 2 O 3 was used as support. The impregnated catalyst had a surface area of about 151 m 2 /g. Activity tests were carried out in a fixed-bed reactor containing 1 g of catalyst and a flow of syngas at a rate of 60 mL/min. The reaction temperature was 170°C and the pressure was 20 barg. The best coprecipitated catalyst gave a CO conversion of about 10%, while the impregnated catalyst gave a CO conversion of up to 69%.

Rice husk is the waste from agriculture industries that has high potential to produce heat and electricity through the gasification process. Air suction mode is new development for updraft rice husk gasification, where blower are placed at output of gasifier. The objective of this research is to examine these new configuration at several equivalence ratio. The equivalence ratio was varied at 32% and 49% to study temperature profile on gasifier, producer gas volumetric flow rate, composition of producer gas, producer gas heating value, cold gas efficiency and carbon conversion. The time needed to consume rice husk and reach an oxidation temperature of more than 700oC for equivalence ratio of 49% is shorter than 32%. Producer gas rate production per unit weight of rice husk increase from  2.03 Nm3/kg and 2.36 Nm3/kg for equivalence ratio of 32% and 49%, respectively. Composition producer gas for equivalence ratio of 32% is 17.67% CO, 15.39% CO2, 2.87% CH4, 10.62% H2 and 53.45% N2 and 49% is 19.46% CO, 5.94% CO2, 0.90% CH4, 3.46% H2 and 70.24% N2. Producer gas heating value for equivalence ratio 32% and 49% is 4.73 MJ/Nm3 and 3.27 MJ/Nm3, respectively. Cold gas efficiency of the gasifier at equivalence ratio 32% is 69% and at 49% is 55%.