Plastic waste can cause serious environmental problems. This can be overcome by various efforts; one of them is by replacing the use of conventional plastic with biodegradable plastic. Biodegradable plastic can be produced from tubers containing starch. The purpose of this study was to explain the suitability of two tuber species with typical protein quality and different starch structures. Starch was obtained from suweg tuber (Amorphophallus campanulatus) and ganyong (Canna edulis Ker). The material invested was obtained by dissolving 4 grams of each starch, each of which was dissolved with distilled water then added with various weight carrageenan. The tensile strength of biodegradable plastic was tested using tensile testing machines, biodegradation of soaked plastics using EM4 (Effective Microorganism) with reduced weight measurements, and Fourier Transform Infra-Red (FTIR) was used to identify the structure of compounds contained in biodegradable plastics. The tensile strength test results of biodegradable plastic from ganyong/canna tubers were 3.35 MPa with elongation of 13.51%, while the plastic from suweg tubers of 2.45 MPa with elongation was 13.68% on the addition of 5% carrageenan, respectively. Plastic degradation testing obtained plastic decomposition up to 100% in 37 days for ganyong and 34 days for suweg, respectively. It showed that the plastics was easily degraded. Identified by FTIR showed chemical structures of OH phenolic alcohols, C = O carbonyls, CO esters, NH amides and amines, and C≡C alkyne.

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Program Kota Tanpa Kumuh (Kotaku) adalah program penanganan kawasan kumuh di kota yang dibiayai dari APBD Kota Yogyakarta dan bantuan dari pemerintah Provinsi Daerah Istimewa Yogyakarta dan juga pemerintah pusat. Salah satu program penanganan kawasan kumuh yang dilakukan adalah di kelurahan Pringgokusuman yang berlokasi di RW 03 dan RW. 22, yang berada di bantaran sungai Winongo. Pengabdian Masyarakat bekerjasama dengan Badan Keswadayaan Masyarakat (BKM) Pringgomukti Kelurahan Pringgokusuman Kecamatan Gedongtengen Kota Yogyakarta. Fokus pelaksanaan program Kotaku adalah pendampingan pembuatan saran pembuangan limbah rumah tangga. Teknis pelaksanaan dengan membangun sistem perpipaan yang meliputi perpipaan air hujan, perpipaan limbah rumah tangga dan perpipaan sanitasi. Di RW tersebut terpasang 5 biofiller beserta sistem saluran perpipaan. Sistem perpipaan dipasang di bawah jalan rumah warga. Sehingga program Kotaku juga merupakan perbaikan jalan perumahan warga. Kontruksi jalan dibangun menggunakan konblok, sehingga menjadi lebih rapi dan bersih serta mudah perawatannya. Kata kunci: kumuh, kota, limbah, rumah tangga

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In order to utilize a raw biogas as a fuel of generator set (gen-set), it is important to figure out optimum operating parameter of the gen-set, i.e. compression ratio. The present work aims to investigate the effect of compression ratio on performance of 3 kW gen-set fuelled with raw biogas and to obtain optimum compression ratio for operation of the gen-set on raw biogas. The gen-set used in the present work is bi-fuel engine, i.e. fuelled with gasoline or LPG. The performance of the engine fuelled with raw biogas in terms of brake power, brake torque, brake specific fuel consumption, and thermal efficiency is evaluated at compression ratio of 7.5, 8.5, 9.5, and 10.5. The work is carried out under electrical load of 240, 420, and 600 Watt. The result indicates that compression ratio affects the rotational speed, brake power, brake torque, brake specific fuel consumption, and thermal efficiency of the gen-set. Optimum compression ratio for the gen-set fuelled with raw biogas is 9.5. At the optimum compression ratio, maximum brake power, brake torque, and thermal efficiency of are 450.37 W, 1.66 Nm, and 46.93%, respectively. Minimum brake specific fuel is 0.59 kg/kWh at the optimum compression ratio.