Abstract. Stinging Nettle (Urtica dioica L., latin) is a wild plant that grows in Indonesia, Asia, and Europe. Nettle in Bali, Indonesia is called as Lateng, Jelatang. Nettle plant has a very strong fiber and high fixed carbon. Nettle plants are covered with fine hairs, especially in the leaves and stems. When it is touched, it will release chemicals, sting and trigger inflammation that causes redness, itching, bumps and irritation to the skin. Nettle plants grow in the wild, regarded as a weed in the agricultural industry, easy to grow and snatch food from the parent plant. The main objective of this paper is to review of the potential nettle fibers and then explain about the potential of local nettle plant in Indonesia. Nettle is a plant group at the end of bast. Its plant fibers taken from the bark, as reinforcement in composite materials. Nettle fibers have three main advantages such as strong, lightweight and low environmental impact.

Makalah ini menganalisis pengaruh perlakukan alkali dan tanpa perlakukan alkali terhadap karakateristik fisik, morfologi dan sifat mekanik serat kulit buah pinang (areca Catechu L.). Selama ini pemanfaatan limbah pertanian belum dilakukan secara maksimal, sehingga dapat menimbulkan pencemaran terhadap lingkungan. Serat kulit buah pinang (Areca Husk Fiber/AHF) selama ini hanya dipergunakan sebagai bahan bakar biomassa dan media tanam sedangkan untuk pemanfaatan lain belum ada sama sekali. AHF diberi perlakukan NaOH 2,5%, 5%, 7,5% dan 10% dengan waktu perendaman 2 jam pada temperatur kamar, untuk mengetahui karakteristik fisik AHF maka dilakukan pengukuran panjang dan diameter serat, pengujian densitas, pengujian kadar air dan moisture sedangkan untuk mengetahui karakteristik mekanik dilakukan pengujian tarik serat tunggal sesuai dengan ASTM D 3379. Dari penelitian ini diketahui bahwa diameter AHF mengalami pengurangan diameter akibat perlakukan alkali, hal ini terkait dengan hilangnya kandungan lignin, pektin dan wax. Densitas AHF menurun dengan meningkatan prosentase NaOH bila dibandingkan dengan AHF tanpa perlakukan NaOH. Kekuatan tarik bervariasi dengan adanya perlakuan alkali.  Kekuatan tarik AHF tertinggi pada serat yang mengalami perlakukan NaOH 5% yaitu sebesar 165 Mpa dan kekuatan tarik terendah pada AHF dengan perlakuan Alkali 10% yaitu sebesar 137 MPa . This paper analyzes the effect of alkali and non-alkali treatments on the physical characteristics, morphology and mechanical properties of betel nut huks fiber (areca Catechu L.). the used of agricultural waste has not been done optimally, causing environmental pollution. Areca Husk Fiber (AHF) only used as biomass fuel and planting medium, while for the other uses it has not existed. AHF was given 2.5%, 5%, 7.5% and 10% NaOH treatment with 2 hours immersion at room temperature, to known the physical characteristics of AHF then measured the length and diameter of fiber, density test, water content and moisture test. Mechanical characteristics of single fiber tensile testing in accordance with ASTM D 3379. From this study that known the diameter of AHF has a reduction in diameter due to alkaline treatment, this is related to loss of lignin, pectin and wax content. The density of AHF decreases with the percentage increase of NaOH when compared with AHF without the treatment of NaOH. Tensile strength varies with alkaline treatment. The highest AHF tensile strength in treated fibers was 5% NaOH of 165 Mpa and lowest tensile strength in AHF with 10% Alkali treatment of 137 MPa.

Waste is one source of greenhouse gas emissions (GHG) that has methane gas form which caused an early multi-dimensional, massive and complex problems. The rapid increase of garbage volume entering landfill, annually result a high garbage dumps in the Suwung Landfill area. It should have been considered a handing solution for example by converting the methane gas content in the waste into a useful value added product. The objective of this research is determining the amount of electrical energy that can be produced through methane gas emission at Suwung Landfill. The characteristic and composition of waste could give effect to the formation of methane emissions. The research on the composition and characteristic of waste were done by sorting 1 m3 of garbage sample from new garbage entering landfill. Garbage is divided based on the source of DLHK waste, market waste, and private waste. The volume of waste that went to Suwung Landfill in 2016 calculated 1.296.438 m3 which was dominated by organic waste (78,1%). The density of the waste that went into Suwung Landfill, based on the research's results, amounted to 135,09 kg / m3, there fore could be assumed that the weight of waste that went to Suwung Landfill in 2016 was 175.135,81 tons. Based on these data, the number of 136.785,13 tons of waste, which was organic waste, could increase the concentration of greenhouse gases in the atmosphere if this situation does not manage properly. Gravimeter method is using for measures the dry matter content value of waste. From the measurement, the results obtained the waste components that have the highest dry matter content is from rubber and leather garbage (76,52%) while the lowest dry matter is food waste (19,13%). By using calculations based on IPCC 2006, it was found that the amount of methane emissions could be generated by the waste at the Suwung Landfill in 2016, amounted to 3.535,06 tons. Based on the energy equivalence table, the electrical power that is generated from the potential methane emissions at the Suwung Landfill is 6,66 MW. Keywords: waste composition, waste characteristics, methane emissions, ipcc2006, electrical power.

This study aims to determine the influence of biofilter made from plastic waste to decrease BOD, COD and Ammonia content and to determine the efficacy of its use to decrease BOD, COD and Ammonia content from the hospital’s wastewater. This study utilized aerobic biofilter processing through a batch system. Variables used in this research are wastewater processing through biofilter media made from plastic waste and processing without biofilter media, with 36 hours retention time. The parameters are BOD, COD and Ammonia content. From the statistical analysis, the use of biofilter media made from plastic waste gives a significant effect to decrease BOD and Ammonia content but made no significant effect to decrease COD. Plastic waste biofilter processing system is very effective to decrease BOD (84,85%), less effective to decrease COD (31,73%) but effective enough to decrease ammonia (50,60%), meanwhile, the standard quality of plastic waste biofilter processing system is effective to reduce BOD and COD content but not effective to reduce the ammonia content after 36 hours of processing time. Further research is needed to study the efficacy of biofilter media made from other type of plastic waste. Moreover, a combination of anaerob-aerobic biofilter processing is required to improve processing efficacy. Keywords: biofilter; plastic waste; hospital wastewater; BOD; COD; ammonia

Tukad Badung River is one of the potential contamination of heavy metal sare very highin the city of Denpasar. Tilapia (Oreochromis mossambicus) isa commonspecies of fish found in the river and became the object of fishing by the public. The fish is usually consume das a food ingredient forever yangler. Fish can be used as bio-indicators of chemical contamination in the aquatic environment. Determination of heavy metal bioconcentration and analysis of liver histopathology gills organs and muscles is performed to determine the content of heavy metals Pb, Cd, and Cr+6, and the influence of heavy metal exposure to changes in organ histopathology Tilapia that live in Tukad Badung. In this observational study examined the levels of heavy metal contamination include Pb, Cd and Cr+6 in Tilapia meat with AAS method (Atomic Absorption Spectrofotometric), and observe the histopathological changes in organ preparations gills, liver, and muscle were stained with HE staining (hematoxylin eosin). Low Pb content of the fish that live in Tukad Badung 0.8385 mg/kg and high of 20.2600 mg/kg. The content of heavy metals Pb is above the quality standards specified in ISO 7378 : 2009 in the amount of 0.3 mg / kg. The content of Cr+6 low of 1.1402 mg / kg and the highest Cr+6 is 6.2214 mg / kg. The content of Cr+6 is above the quality standards established in the FAO Fish Circular 764 is equal to 1.0 mg / kg. In fish with Pb bioconcentration of 0.8385 mg / kg and Cr+6 of 1.1402 mg / kg was found that histopathological changes gill hyperplasia and fusion, the liver was found degeneration, necrosis, and fibrosis, and in muscle atrophy found. Histopathologicalchangessuch asedema and necrosis ofthe liveris foundin fishwith Pb bioconcentration of 4.5225mg/kg and Cr+6 amounted to2.5163mg/kg. Bio concentration of heavy metal contamination of lead (Pb) and hexavalent chromium (Cr+6) on Tilapia ( Oreochromis mossambicus ) who lives in Tukad Badung river waters exceed the applicable standard. Histopathological changes occur in organs gills, liver, and muscle as a result of exposure to heavy metals lead and hexavalent chromium. Advised the people not to eat Tilapia that live in Tukad Badung