Judul: Karakterisasi Pertumbuhan Mikroalga dan Eliminasi Nutrien dari Limbah Cair Peternakan dengan Sistem Semi Kontinu
Abstrak: One way of wastewater treatment is a biological process with the help of a combination of microorganism such as bacteria and microalgae. Degradation organic content of waste water by bacteria and then the result of degradation by bacteria in the form of nitrate and CO2 utilized by microalgae. Microalgae also produce O2 as a result of photosynthetic bacteria that can be used. The growth of microalgae is very closely related to the availability of macro and micro nutrients as well as influenced by environmental conditions. Microalgae needed nutrients consist of macro nutrients (N, P, K, S, Fe, Mg, Si and Ca) and micro nutrients (Mn, Zn, Co, Bo, Mo, B, Cu, etc. ). Environmental factors that influence the growth of microalgae, including light, temperature, water pH, and salinity. The purpose of this research to know microalgae growth caracterization in wastewater cattle breeding and to know nutrient eliminate caracterization from wastewater cattle breeding on microalgae cultivation with semi-continuous system. In this research, microalgae was cultivated, using microalgae inoculum from Lake LSI IPB and use wastewater of cattle breeding from MT Farm Ciampea. Pretreatment wastewater used aerator in a tank for five weeks. The purpose of this pretreatment to reduce odor generated liquid waste and reduce organic matter content. In a preliminary study done by two microalgae cultivation treatments on the vessel I (75% wastewater: 25% inoculum microalgae) and the vessel II (50% wastewater: 50% inoculum microalgae). Techniques of microalgae culture has done semi continuous. Harvesting was conducted periodically, and the addition of nutrients to the volume culture as much as the amount have harvested. Of the two treatment obtained a preliminary study of the best cultivation method is in the vessel I, where the abundance of microalgae were compared with the second vessel. At the main study by using waste ratio 75%: 25% visible microalgae abundance of microalgae in the early experiments of H-12 and the harvesting of 25% with semi-continuous system, and the H-16 was again semi-continuous harvesting system as well as 75%. From this treatment more quickly visible growth after harvesting microalgae microalgae as much as 75%, because the waste was added too many (75% = proportional to that harvested). In the first experiment with detention time of 12 days nitrogen concentration was decreased 5.79%, orthophosphate concentration was decreased 0.34%, and COD concentration was decreased 75%. In the second experiment with two days detention time nitrogen concentration was decreased 0.63%, orthophosphate concentration was decreased 0.15%, and COD concentration was decreased 33%. In the third experiment with detention time of 6 days the nitrogen concentration was decreased 3.14%, orthophosphate concentration was decreased 0.42%, and COD concentration was decreased 78%. Harvesting with the test results of TSS in H-12 abundance of microalgae in 2135 mg / L. Microalgae are good for handling wastewater has a high nutrient content. In addition nutrient content that have contained in mediakultivasi, light, temperature and pH are important factors also in microalgae cultivation. To enhance the ability of microalgae to eliminate the nutrient contained in the wastewater, waste volume ratio must be greater than the volume of microalgae.
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Judul: Kultivasi Konsorsium Alamiah Mikroalga dengan Memanfaatkan Nutrien pada Berbagai Limbah Cair Agroindustri
Abstrak: During the last two decades, Indonesian economic growth focused on industrial development especially agroindustrial sector (Suardana, 2008). As a result, agroindustrial wastewater pollution became serious problem. Organic wastewater with high nutrient content can stimulate uncontrolled microalgae growth (Pustekkom, 2005), whereas discipline control can be very profitable. According to Pirt (1986), microalgae is low level vegetation (5 – 30 2m) with high productivity and efficiency in biofuel producing through photosynthesis. Its productivity in producing triglycerides reached 100 000 L/ha, while oil palm reached only 5 950 L/ha (Kabinawa, 2008). Specific cultivation of microalgae raised feasibility problem particularly in Indonesia. Cultivation of natural microalgae consortium in many agroindustrial wastewater, will be delivered to produce dominant, natural selected microalgae with good ability to survive in such extreme condition. This research was performed to determine the effect of several agroindustrial wastewater as nutrient in microalgae natural consortium cultivation. In addition, application of coagulation/flocculation and centrifugation method for separating/harvesting microalgae was also investigated. In the early stage, preparation was performed to create cultivation vessel based on raceway design, characterization of agroindustrial wastewater (slaughterhouse wastewater/L1, livestock wastewater/L2, and sugar mill wastewater/L3), characterization of microalgae natural consortium from LSI Lake- IPB, and also making of trial cultivation. Next stage, primary cultivation was launched in wastewater medium with circulation, wastewater medium without circulation, and synthetic wastewater medium (in many concentrations of NPK fertilizer, without circulation). In the last stage, separation of consortium after cultivation was carried out with centrifugation, and also coagulation/flocculation with alum and polyaluminium chloride (PAC). Characterization of wastewater showed that L2 contain the highest nitrogen (1 490 mg/L) and potassium (304.70 mg/L) concentration, but orthophosphate concentration (8.0 mg/L) lower than L1 (14.8 mg/L). Meanwhile L3 had nitrogen (0 mg/L), orthophosphate (0.6 mg/L), and potassium (107.70 mg/L) concentration at the lowest. Microalgae consortium cell density attained 2 250 000 cell/ml, and its prevalence showed that there are three species of chlorophyceae in large amount, Selenastrum sp., Ankistrodesmus sp., and Dictyosphaerium sp.. Uncounted species in consortium assumed to be in very small amount. Cultivation in wastewater medium with circulation showed that complete microalgae growth phase occurred in 20 – 30 days. During the phase, nutrients such as N, NO3 -, PO4 3-, and K decreased, however, fluctuation occurred (especially NO3 - and PO4 3-) by the perpetual conversion activity which related to food chain between microalgae and the other contaminant microorganisms. Its pH value ranging in proper microalgae growth pH from 7 to 9 but tend to be 8. Drastic color change according to chlorophyceae growth was not appeared due to effect of circulation on the chlorophyll amount. Next cultivation was carried out without circulation in wastewater medium. During 16 days cultivation, complete growth phase was well-detected. NO3 -, PO4 3-, and K concentration also showed decreasing trend, while pH value ranging from 6 to 9 but also tend to be 8. Cultivation in synthetic wastewater medium, consist of 9 serial concentrations of NPK fertilizer (Sy1 – Sy9), was run to prove that nutrient concentration affect the growth rate of microalgae. As a result, the growth peak of Sy3
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Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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