Judul: The Influence of Honeycomb Biofilter Application in Organic Wastewater Treatment of A Combined Anaerobic and Aerobic System (Case Study : Waste of Tofu and Fermented Soybean Cake Industry)
Abstrak: The objective of this study are to assess the influence of honeycomb biofilter application in degrading organic pollutant at combined anaerobic and aerobic system, and also to assess the possibility for applicating this technology in tofu and fermented soybean cake industry. This study was carried out in tofu and fermented soybean industry at Semanan, west Jakarta, that have around 800 small industries which has been operated since 1992. The total amount of wastewater produced from that area is about 846 m3/day, and is collected in wastewater lagoon nearby. Wastewater treatment of a combined anaerobic-aerobic system is a secondary wastewater treatment after physical treatment. Basically this wastewater treatment relies on bacteria in degrading pollutants. The use of honeycomb biofilter is to increase specific surface of media for attachment of bacteria. The Biofilter is made of plastic, 28 cm x 25 cm x 30 cm, very light and easy to clean. The system consist of two reactors that is made of 8 mm glass, and the volume of each reactor is 140 liter (so total volume of reactors is 280 liter). The reactor is equipped with two circulating pump and blower in the aerobic zone. It takes 14 - 25 days for seeding. The reactors run in four different resident times, namely 7 days, 5 days, 3 days and 1 day. The raw water used in this experiment is wastewater from tofu and fermented soybean cake industries that have 8005 around 300 - 500 mg/I. The water for physical and chemical analysis is sampled weekly. It took from raw water and each colum of reactor. Bacteria analysis was also carried out to investigate the presence of bacteria using carbohydrate and protein as main component of wastewater. Bacterial population decreased significantly at the end of the proses. The results from 1,872 physical and chemical parameters from 144 water samples showed that the reactors using biofilters have better performance than the reactors without biofilters. The Efficiency process in decreasing 8005 value is up to 90.24%, COD 74.43%, ammonia 98,68%, nitrite 87.64%, nitrate 94.76%, sulfide 100%, and total phosphate 97 .60%. Besides such a good relatively high efficiency, the hydraulic loading is around 0,48 - 3,33 m3/m2 of surface biofilter media each day and BOD loading is around 0, 20 - 0,43 kg BO05 / m3 of biofilter media each day. Economic assessment of small industry that used 100 kg soybean as raw material, need investment Rp. 5 562 000,- and operation cost Rp. 68 440,- every month or equivalent with Rp. 463,-/m3 wastewater.
Keyword: Biofilm, Organics, Sewage, Biofilter, Wastewater Treatment, Anaerobic and Aerobic Reactors, Organic Waste, Waste of Tofu, Fermented Soybean, Cake Industry

Judul: Sustainability Assessment of Biogas Production from Tofu Wastewater Using Composite Indicator: (A case study in tofu industry Giriharja, Sumedang)
Abstrak: Tofu industries in Indonesia was dominated by Small Medium Enterprices (SMEs) that not implemented wastewater treatment due to several limitation, such as technological knowledge and cost. However, various grant had been given, one of which was from Lien Fooundation and NEWRICOMM, Singapore that colaborated with Research Center for Environmental and Clean Technology, BRIN to install Wastewater Treatment Plant (WWTP) in Giriharja. Several biogas project grants were no longer operated, indicating the importance of sustainability assassment. Since, 70% management control came from post installation that played important roles for the capability of WWTP to run normall. In this study, composite indicator (CSI) was used due to their ability to assess the effectiveness, efficiency, and the impact of biogas production in WWTP. A composite indicator is formed when individual indicators were compiled into a single index, on the basis of an underlying model of the multi-dimensional concept that being measured. Using CSI, the different of measurement units from indicators could transformed as unitless by normalization and thourgh aggregation would be obtained a composite values from several indicators. This study was conducted in Giriharja WWTP, where treated tofu wastewater from 9 SMEs with 2,014 kg soybean/day. The WWTP could produced biogas which used as cooking energy by the households. The aim of this study was to assess sustainability of biogas production in WWTP using Composite Indicator (CI), steps: i) selection and assessment of indicators, ii) CSI assessment, and iii) impact evaluation. The selected indicators were 2 Environment indicators (waste managment and clean production (water quality) dan Green House Gas (GHG) emmision; 5 Social indicators (public acceptance, odor, visual impact, technological complecity, and bioenergy used to expand access modern energy service); and 3 Economic indicators (productivity, net energy balance/NEB, energy diversity). Indicator values from baseline scenario in GHG was 5.67 Gg-CO2 eq/year without COD reduction. Public acceptance, odor, and visual impact values were 96.15%; 90.38%; and 90.38% respectively. Meanwhile, energy diversity was 0.92 with energy comsumption composition LPG+biomassa dan LPG were 4 and 96% respectively. Biogas scenario showed 3.17 Gg-CO2 eq/year GHG emission with COD reduction effesiency was 93.35%. Public acceptance, odor, and visual impact values were 69.23%; 9.62%; dan 13.46% respectively. Biogas scenario values has higher technological complecity than baseline (LPG), hence the biogas production gave acecible of modern bioenergy for 49.32% of respondents. The biogas productivity was 0.13 MJ/m3 wastewater with NEB values 124.48 MJ/ton tofu wastewater and the ratio efficiency of anaerobic digester operation valued 55.04. Energy diversity valued 0.59 with energy comsumption composition: LPG, Biogas+LPG, and Biogas were 26, 72, and 2% respectively. CSI value on environment for biogas scenario (0.30) had higher sustainability than baseline (0.01) with the implementation of tofu wastewater managment. Social dimension high influenced by the higher weight of technological complecity. Meanwhile, economic sustainability of biogas scenario (0.11) higher than baseline (0.01). The impact of biogas production from environment sustainability perspective could reduce GHG emission 2.50 Gg-CO2 eq/year which indicated the improvement of environment. In social dimension, biogas scenario impact could reduce odor and river pollution. Regarding the performance of WWTP, could produced biogas 59.25 m3/day. According to
Keyword: iogas, Sustainability, Tofu wastewater, Composite Indicator

Judul: Konstruksi aritmetika kurva eliptik F(2m) supersingular dan non-supersingular untuk skema kunci publik ElGamal
Abstrak: Algoritme ElGamal adalah salah satu algoritme kunci publik dengan aritmetik modular p yang mempunyai struktur grip siklik Z(p). Tingkat keanaman algoritme ini terletak pada pemecahan masalah logaritme diskret dari Z(p). Akan tetapi, tingkat keamanan tadi tahun ke tahun semakin menurun yang disebabkan kemampuan pemecahan algoritme diskret semakin meningkat. Untuk memenuhi tingkat keamanan yang memadai dibutuhkan p yang cukup besar yang menyebabkan proses enkripsi dan dekripsi menjadi lambat.
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