WASTEWATER SPECIFIC EMISSION FACTOR FROM COMMUNAL WASTEWATER TREATMENT PLANT (WWTP)

Greenhouse gasses (GHG) that produced by anaerobic digestion of wastewater consists of CH4 gas and NO2 gas. Beside the data of specific activity, the specific emission factor also plays important part to determinate GHG emission. The aim of this paper is to know specific emission factor value from communal wastewater treatment plant (WWTP), as an input to determinate GHG emission for determination of GHG emission reduction rate. The data was collected by taking sample of BOD, CH4 gas, and CO2 gas from communal WWTPs. Sampling location were communal WWTPs in Jakarta City, Bandung City, and Yogyakarta City. Those WWTPs using anaerobic baffle reactor as their treatment system with capacity varied between 40-200 EP. The parameters were BOD and CH4 that measured using grab sampling in the morning and evening. Data analyzed by quantitative methods. The specific emission factor value was determined from CH4 gas measurement which affected by wastewater treatment unit dimension, gas catcher chamber, and air suction pump capacity. The analysis results showed specific emission factor for communal WWTPs from the three cities is 0.00171 kg CH4/kg BOD. The value has bid difference when compared to IPCC’s default that is 0.48 kg CH4/kg BOD. This is due to the formation of CH4 gas and CO2 gas was strongly influenced by environmental condition in real time condition. This factor is not taken into consideration in IPCC’s default

POTENSI ENERGI LAMUN UNTUK MENDUKUNG PELESTARIAN DUGONG (DUGONG DUGON) DI DESA BERAKIT DAN DESA PENGUDANG PULAU BINTAN

Dugong dugon is belong of the Order Sirinedae, family Dugonidae, known as a seagrass specialist and been categorized into endangerd species. In Bintan Island, these animals are found in the North season (December to February). This study aims to determine the potential of seagrass energy as dugong food which appeared in the Berakit and Pengudang village. Collecting of seagrass biomass was conducted in May 2015. A total of 40 transects squares measuring 1 x 1 meter used to take seagrass biomass. Seagrass energy is obtained by converting biomass into energy units. The result shows that seagrass energy in the Berakit village are 1.04 x 1012 Joule or can feed 51,000 – 88,000 dugong, whereas the Pengudang village are 6.64 x 1011 Joule or can feed 32,000 – 55,000 dugong. The potential seagrass derived from Halodule uninervis in Pengudang village can feed 589 - 1000 dugong. The seagrass in both of villages have great potential for dugong feed but the anthropogenic disturbances should be considered.  It is suggested that seagrass on the eastern coast of Bintan Island need to be managed seriously

MODELING OF SEPTIC TANKS SEEPAGE NEAR DUG WELLS IN MARGAHAYU VILLAGE, BANDUNG REGENCY

Dense settlements have an impact on pollution, one of which is domestic pollution which results in groundwater and soil water pollution at ground level. Identification of pollution that occurs below the soil surface (groundwater contamination) is more difficult to detect, so modeling is needed to find out how the rate of groundwater pollution rate. Modeling is done by using water sampling method at dug well at location adjacent to septic tank. Sampling ground water and infiltration modeling is done by using Geostudio SEEP/W software. The research area is in Margahayu village, Bandung regency. The results of laboratory analysis and physical observation in the field show that the Margahayu region has ammonium (NH4-N) content which is above the standard quality threshold. This condition is reinforced by modeling simulation results that there has been domestic sewage from septic tanks to dug wells. Pollution has reached groundwater level with depth ranged between 4-5 meters. The distance of wells adjacent to the septic tanks affects the quality of groundwater. In the KB area 17 it is indicated that the contamination in the residents' wells in harike-3i, KB new on the 32-40 day time frame, and KB new 2 on the 24th day. Distance sources of contaminants and soil permeability play an important role in determining the travel time of contaminants

CORROTION RATE AND MORPHOLOGY OF POROUS METAL ALLOY Mg-Ca-Zn WITH CaCO3 AS FOAMING AGENT

Magnesium alloy is a material that has been developed as a biodegradable implant material in orthopedic applications. Magnesium alloys have good biocompatibility, biodegradability, and good mechanical properties which make them have the potential to be used as a biomedical material. The main objective of this paper is to investigate corrotion rate and morphology after corrotion of biocompatibility of implant-based alloys Mg-Ca-Zn with CaCO3 as a foaming agent. Mg-Ca-Zn Alloy was made by the method of powder metallurgy with the addition of CaCO3 as a foaming agent with three variations of composition (96Mg-Ca-3Zn-CaCO3, 91Mg-Ca-3Zn-5 CaCO3, and 86Mg-Ca-3Zn-10 CaCO3 wt%). Sintering process was carried out at 600 °C and 650 °C with a holding time of five hours. Corrosion test was performed using G750 Gamry Instrument in accordance with ASTM standard G5-94. Simulated body fluid electrolyte used is Hank's solution with a pH value of 7.4 and a temperature of 37 °C. Then the analysis of the microstructure after corrosion test was conducted using scanning electron microscopy (JEOL, JSM-6390A Japan) equipped with energy dispersive spectrometry data (EDS). Alloy corrosion rate of Mg-Ca-Zn-CaCO3 increases with the amount of CaCO3 in the alloy and the temperature rise in the sintering. From the test results, the smallest corrosion rate is in the alloy 91Mg-Ca-3Zn-CaCO3 at 600 °C sintering (58.3045 mpy) and the highest occurs in alloy 86Mg-Ca-3Zn-10CaCO3 at 650 °C sintering (91.4007 mpy). Surface morphology of the alloy after the corrosion process is the type of volcano. This localized corrosion occurs where an electrochemical reaction takes place to form a distinctive structure with a circle and a hole in the middle

LOCAL MATERIAL TESTING FOR PAVEMENT MATERIAL ON REMOTE AND OUTMOST ISLAND

Road infrastructure development in remote and outmost islands such as Mentawai, Aru, and Morotai faced a problem i.e. dificulty in the availability of standard material. The standard material had to be transported from other areas that taking a long time and high cost of transportation. In fact, the three islands had abundant materials. However, there was no study conducted to examine the properties of the local material. The study aim was to find out the physical properties of pavement material that will be the basis of pavement design. The research began with the selection of material, discussion with experts, coordination with involved parties, site observation, and laboratory test. The analysis of testing result used comparative analysis that compared test result to certain standard. Based on the analysis, local material from Mentawai Islands was suitable for foundation layer with cement stabilization 6%. Coral from Aru Island and limestone from Momojiu Morotai Island could also be utilized for foundation layer. Limestone from Rau Morotai Island utilized for aspalt mixture. Sand from Aru Island and sea sand from Morotai Island could be used for aspalt mixture and concrete cement mixture

SIZE DISTRIBUTION AND CONDITION FACTOR OF SPINY LOBSTER (Panulirus homarus Linnaeus 1758) IN PANANJUNG PANGANDARAN

Perairan Pangandaran merupakan salah satu wilayah penyebaran lobster yang potensial di bagian Selatan Jawa Barat. Jenis lobster yang tertangkap di Perairan Pangandaran antara lain: lobster pasir (Panulirus homarus), lobster batu (P. penicillatus), lobster mutiara (P. ornatus) dan lobster bambu (P. versicolor). Pengukuran lobster dilakukan pada bulan November-Desember 2015 dan Januari-Februari 2016 untuk mengetahui sebaran ukuran populasi dan faktor kondisi lobster pasir. Hasil pengukuran 826 ekor lobster pasir, menunjukan sebaran ukuran lobster pasir jantan berkisar antara 3,1 – 8,9 cm (CL) sedangkan ukuran lobster betina berkisar antara 3,4 – 8,5 cm (CL). Hasil analisis hubungan panjang bobot, lobster pasir di Pangandaran memiliki pola pertumbuhan isometrik. Nilai koefisien kondisi fulton (K) dan berat relatif (Wr) hasil analisis, mengindikasikan bahwa kondisi perairan Pangandaran kurang mendukung untuk pertumbuhan lobster

DIVERSITY, COMPOSITION AND UTILIZATION OF MOLLUSC IN SAPARUA ISLAND, CENTER MOLUCCA

Saparua Island is one of the islands in the Central Moluccas that has a complete ecosystem, unfortunately records on mollusk research is very limited. The aim of this research is to know the composition, diversity and utilization of mollusk. The objectives of the study are to determine the composition, diversity and utilization of mollusks using square transect and free collection method which conducted on April and September 2016. Water analysis is also done to determine the environmental hydrographic condition. Temperature and salinity indicate the presence of freshwater input through rivers, especially in St-2 2 (Waisisil). Concentrations of nutrients show a fairly high value, ranging from 0.001 to 0.114 mg L-1 for phosphate; 0.012 - 0.023 mg L -1 for nitrate and 0.140 - 0.443 mg L -1 for silicate. There are 641 individual mollusks of 107 species consisting of 85 species of Gastropoda and 22 species of Bivalves. Species found mostly by Littoraria scabra (Littorinidae), Cypraea annulus (Cypreidae), Terebralia sulcata (Potamididae); Clypeomorus battilariaeformis (Cerithiidae); and Nerita chamaeleon (Neritidae). The existing mollusk community has moderate and uniform diversity with low species dominance. There are at least 35 species of mollusks that can be utilized into various commodities such as food products, accessories/decorations and raw materials of drugs

SOLVENT EXTRACTION PROCESS FOR THE RECOVERY COBALT AND NICKEL FROM LOW-GRADE LATERITE USING BATCH RECYCLE SYSTEM

Low-grade laterite which contains nickel lower than 0.5 % is difficult to beprocessed using pyrometallurgy. One method which isable to solve this problem is solvent extraction. In thisstudy, a solvent extraction process using batch recycle methods has been successfully applied to separate nickel and cobalt from low-grade laterite. Sulphuric acid was used to leach laterite at atmospheric pressure. Meanwhile, cyanex in toluene was used as an organic solvent. Taguchi experimental design has been used to analyze and optimize the solvent extraction process using batch recycle methods. Taguchi analysis results show that the optimum conditions are at 7 of pH, 3 hours of time operation, 0.9 liter/minute of flow rate and 0.75 of organic/aqueous solutions ratio.

THE EFFECT OF SURFACE ROUGHNESS AND STIRRING SPEED ON THE COATING CHARACTERISTICS OF MARTENSITIC ELECTROLESS Ni-P

Coating process of martensitic stainless steel 420 (SS 420) as the base material component of the steam turbine blade component uses an Electroless Ni-P coating process. This process is one of the solution coatingsthat applied to stainless steel as a substrate to improve corrosion resistance.The goal of this research is to get an idea and information about the effect of surface roughness and stirring speed on the characteristics of Electroless Ni-P layer. Experimental parameters in this research were variations of 0.044 μm, 0.056 μm, 0.101 μm, and 0.164 μm surface roughness and variations of 4.9 rpm, 11.3 rpm, and 21.3 rpm stirring speed. Results showed that the surface roughness and low stiring speed causes the grain distribution becomes more uniform, whichis shown by Scanning Electron Microscopy (SEM) examination. Adhesion layer also increases along with increasing levels of surface roughness. The highest value of adhesion was 1.9 MPa at 0.164 μm and the lowest value of adhesion was 0.8 MPa at 0,044 μm