Applied Mechanics and Materials Vol. 898

Abstract: The high levels of Fe²⁺ metal ion in water can be reduced by adsorption process. The adsorbent used is a composite of chitosan activated carbon. The composites were prepared by adding 1.5 g of activated carbon into chitosan solution 1.5% (w/v). The gels of chitosan activated carbon were then dropped into a 2.8% NaOH solution mixture to produce composite beads. The beads were neutralized using aquadest and dried in an oven at 50oC for 2 hours. The dried bead was used as adsorbent. The adsorption process was carried out with erlenmeyer in shaker bath with 0.5 g, 1 g, and 1.5 g at 25oC, 35oC and 45oC in 50 mL solution of Fe²⁺ metal ion having concentration of 10 ppm. Sample were taken in 5, 10, 20, 40 60, 80 and 120 min. Adsorbent were characterized by SEM and EDX. The composite beads adsorbent was analyzed by SEM and EDX. SEM results show that chitosan was successfully coated on activated carbon with a porous surface structure. The EDX results show that chitosan activated carbon composite beads can absorb Fe²⁺ metal ions, with an adsorption capacity of 88.3% at 60 min in 1.5 g adsorbent dose.

Abstract: Oyong fiber (OF) is widely available natural fiber, the material characteristics and porosity make it a suitable alternative for filtration media. Accordingly, to investigate the potential use of OF as filter material in the wastewater disinfection process, this study applied different silver nanoparticles coating onto OF and proposed a new filter structure at lower cost. The OF coated AgNPs and OF coated Ag-GO were successfully synthesized following the chemical reduction methods as reported in the literature. SEM image shown that silver nanoparticles were randomly distributed on the surface of OF. Both OF coated AgNPs and Ag-GO exhibited a good disinfection capability for Total Coliform removal from wastewater. The OF coated Ag-GO have better Total Coliform Log Removal Value (LRV) of 3.3 and still maintain stable disinfection ability even at high filtration rate.

Abstract: Sleman Regency, Yogyakarta Province, Indonesia has around 1,056.87 tons of unmanaged waste per day, with 74.22% of its composition is food waste. This phenomenon can be reduced by using an efficient composting method using modified aerobic reactors. The purpose of this research is to identify the quality and quantity of compost as well as larvae (maggots) produced. The research was done for 30 days using two reactors that have different feedstock composition, i.e., the comparison of food waste: vegetable waste of 1:3 (first reactor) and 3:1 (second reactor). The initial mass of each feedstock was 8 kg. The result of composting showed that the compost weight was shrinking by 92.5% in reactor one and 89% in reactor two. The results of the analysis also showed that the second compost reactor had better qualities than reactor one, but the maggot protein content of the first reactor is better than the second reactor. The moisture content in the first reactor did not meet the standards (Indonesian National Standard/SNI of compost), whereas in the second reactor, the standards were achieved with the moisture content being 20.63%; P 1.55%; K 1.45% and C/N 14.03%. The content of NPK in liquid compost produced from the first reactor was 0.18% N; 0.05% P and 0.76% K, while the liquid compost in the second reactor contained 0.30% N; 0.04% P and 0.58% K.

Abstract: Spent catalyst is listed as one of the hazardous wastes. Based on the toxicity characteristic shows that spent catalyst contains some heavy metals at concentration above the regulations limits. This situattion becomes an important issue in nowadays. In this research, fungus Aspergillus niger was investigated to produce weak organic acid (citric acid). Batch experiments were performed to compare the leaching efficiency from spent catalyst of pulp density (2% and 4%) and particle size (212 µm, 150 µm and 75 µm). Result showed that after direct bioleaching process, maximum recovery of valuable metal 24.94%, 7.42%, 1.09%, 3.51%, 4.87% and 1.66% were achieved for aluminum, calcium, iron, copper, silver and platinum respectively at 2% pulp density. Overall data shows that metal recovery at pulp density 2% are higher than 4% pulp density. The maximum recovery based on particle size shows that the smaller particle (75 µm) the higher metal recovery (Al, Ag and Pt) and for some metals was different such as Fe, Cu and Ca.

Abstract: Ramie solid waste as chips can be used as raw material for pulp. Ligninolytic enzymes of laccase widely used for pretreatment of the pulping process of ramie chips by biodelignification using laccase produced by Penicillium sp. LX/08 has been done. This study aims to obtain optimal concentrations of lignin and CuSO₄ as enzyme inducers to increase laccase production from Penicillium sp. LX/08 during biodelignification process and its effect on the quality of ramie pulp. The biodelignification process of ramie chips was carried out by solid state fermentation (SSF) method with six days incubation time. Two inducer type treatment factors (CuSO₄ and lignin), and variations in the concentration of each lignin (0.25 g/L, 0.5 g/L, 0.75 g/L) and CuSO₄ (0.25 mM, 0.5 mM, 0.75 mM) were investigated in this study. The pulping process was carried out by the soda process in a digester under conditions: 12% active alkaline, temperature of 165^°C for 3.5 hours. The results showed that 0.75 mM and 0.5 g/L of lignin were the optimal concentrations which could increase the laccase activity of Penicillium sp. LX/08 by 343 U/L and 25,8 U/L, respectively. The quality of ramie pulp showed a decrease in Kappa Number of 9,34% with an increase in pulp yield to 55,43%. Based on these results, the pretreatment method using laccase produced by Penicillium sp. LX/08 can assist the pulping process of ramie.

Abstract: Rubber compound supplies are very important in supporting the outsole production process, in order to obtain good results and increase production efficiency. However, the rubber outsole company at west java used excessive rubber material for producing outsole. Furthermore, the situation is identified as the company has an inefficient distribution system of the rubber compound. Therefore, there is an abundant solid waste of rubber compound in the outsole pressing process. This research aims to reduce the waste of rubber compounds by regulating the rubber compound distribution using Material Requirement Planning (MRP) with a fixed order quantity lot-sizing technique. The using of MRP will lead to the consumption of the rubber compound can be controlled properly. Moreover, by reducing the utilization of rubber material, the company can minimize solid waste. The result shows that the company can reduce 38.75 kg/day rubber material for production line 1, while 3.69 kg/day for production line 2. Therefore, in one year the company can cut the consumption of the rubber material about 23.57 tons. By reducing the utilization of rubber material, the result indicates that the method can reduce the loss of production worth Rp. 5,240,000/day. Furthermore, this paper also recommends incorporating demand uncertainty of the outsole product in future research.

Abstract: The tropical ecosystem had high biomass productivity but still less in economic values. Integrated Bio-cycle Farming System (IBFS) was an alternative system that harmoniously combines agricultural sectors (agriculture, forestry, animal husbandry, fishery, plantation estate, horticulture) and non-agricultural aspects (industry, household, infrastructure, the marketplace) on integrated ecological management. The key characteristics of IBFS developed in UGM University Farm were (i) an integration of agriculture and non-agriculture sector, (ii) value of environment, esthetics and economics, (iii) rotation and diversity of plants, (iv) artificial and functional biotechnology, (v) management of closed organic cycle, (vi) ecosystem health management, (vii) agropolitan concept, (viii) specific management of plant and (ix) holistic and integrated system. The management of cycle of energy, organic matter and carbon, water, nutrient, production, crop, money conducted through 9R (reuse, reduce, recycle, refill, replace, repair, replant, rebuild, reward) to obtain optimal benefits for global environment and livelihood. The system had a sustainable multifunction and multi-product (food, feed, fuel, fiber, fertilizer, biopharma, water, energy, oxygen, edutainment, eco-tourism). They would meet the expected basic need for daily-, monthly-, yearly- and decade’s income at short-, medium- and long- term periods. IBFS was a good prospect for sustainable economic, environmental, and socio-culture aspects.

Abstract: The implementation of the waste management technology in Integrated Waste Management Site, in Bahasa: Tempat Pengolahan Sampah Terpadu (TPST) Piyungan of the Special Region of Yogyakarta Indonesia has not been optimal and it has negative impact, especially on environment and surrounding community. TPST Piyungan has both positive impact of opening employment for waste pickers as well as negative impact of pollution in surrounding environment. Increasing of solid waste input is not balanced with the processing rate. Concerning with the aforementioned background the study aimed at studying the people perception of waste management in the TPST Piyungan and formulating a new paradigm for solid waste management in TPST Piyungan by proposing a waste-to-energy technology that able to solve the existing problems and become a business-centered activity instead of cost-centered, or in short term waste-entrepreneurship (wastepreneurship). The study was conducted in TPST Piyungan and surroundings villages as samples. The study used quantitative analysis method. People perception were collected using questionnaires distributed to 30 respondents in nearby villages. Proposed technology was selected using Green Quality Function Deployment (GQFD) and Less Objective Criteria (LOC). Economic evaluation parameters are Net Present Value (NPV), Internal Rate of Return (IRR) and Payback Period. The results of the study showed that 70% of the villagers accepted the presence of the advanced waste management in the TPST Piyungan. The results of GQFD and LOC showed that incinerator was the selected technology. The results of economic showed that incinerator was economically feasible with the NPV of IDR 86.09 billion, the IRR of 13.35%, and the net profit margin in the range of 6.89 – 18.79% in the operational period of 18 years, and the static payback period of 7 years. Therefore, the implementation of wastepreneurship in form of social, economic, technical and environment is highly potential.

Abstract: The daily waste tonnage at Piyungan landfill is 600 tons consisting of organic and combustible waste which can be used as an energy source. The aim of this study is to determine the potential energy of waste in the Piyungan landfill by its characteristics based on technology options including landfill gas, anaerobic digestion, gasification, and incineration. The Piyungan landfill mostly contain organic waste, up to 62.1% and combustible waste (RDF) at 26.8%. Moisture content of Piyungan’s RDF is higher than international standards for RDF as raw material in several countries. The various result for Nett Calorific Value is about 7.27 MJ/kg for fresh waste, 12.78 MJ/kg for RDF, 1.74 MJ/kg for market waste and 4.14 MJ/kg for mining waste. Landfill gas can generate energy up to 1.2 MW at the beginning and reaches 2 MW during peak periods. The potential energy by using anaerobic digestion and gasification technology are 1.54 MW and 3.12 MW. By incinerate fresh waste, the potential energy can be generated up to 9 MW and 4.39 MW when incinerate RDF waste only. Calculation of potential energy can be used as a basis for selecting the right technology, especially for economic feasibility for each technology.

Abstract: Fertilization for agriculture and plantation nutrition still dominated by chemical fertilizers. Organic fertilizers utilization for soils is believed has not had the same quality as existing fertilizer standards. On the other hand, increasing waste problems has become environmental issues that have not been properly resolved. MSW process by using MBT Method is able to change the waste management system and produce RDF Fluff products as alternative fuels and compost fertilizers. Research have showed that the quality of organic fertilizer from the Mechanical Biological Treatment (MBT) process met the SNI 19-7030-2004 parameters with the total N = 1.38%, P₂O₅ = 0.66% and K₂O = 2.34%. Production cost of making organic fertilizer is lower than NPK and the amount used for ground application is higher than NPK. Market confidence began gradually improving due to consumer increasing demand.