Judul: Pengaruh nilai F/M (Food to Microorganism ratio) kolam lumpur aktif pada efesiensi penyisihan polutan organik dalam instalasi pengolahan air limbah industri tepung agar-agar
Abstrak: Seaweed is one of the commodities that are potential to develop, and from the data in the last 5 years, seaweed production in Indonesia reached 2.6 million tons per year valued Rp. 18 billions. One way to add value to seaweed is to process it to become agar powder. Despite of the positive impact to economy, agar powder industries also give negative impact emerges form those activities which is the waste water. The objectives of this research were to study the effects of F/M (Food to Microorganism) ratio of waste water treatment in agar powder industry, and to determine the optimum F/M ratio of activated sludge process to waste water treatment plant (WWTP) of agar powder industry. The initial research was done to characterize the waste, including COD and TKN analysis (Total Kjeldahl Nitrogen). In order to determine the parameter of F/M ratio, the sampling were done in five level of resistance time treatments, which were HRT 2.5 days, HRT 2 days, HRT 1.5 days, HRT 1 day, HRT 0.5 day in F/M ratio of 0.5; 0.4; 0.3; 0.2; and 0.1. The treatment of hydraulic resistance time led to the difference in COD removal values. The F/M ratio used in waste water treatment plant (WWTP) was the best ratio, which were 0.2 and 0.3. The efficiency of COD removal of F/M ratio 0.2 in resistance time HRT 2.5 days was 77.91 % while F/M ratio 0.3 in resistance time HRT 2.5 gave the efficiency of COD removal as much as 69.17 %. It showed the most efficient removal in agar powder’s waste water treatment was in F/M ratio of 0.2 with HRT of 2.5 days which was 77.91%. According to COD quality standard, the removal value in 0.2 F/M ratio and 2.5 days HRT met the existing standard.
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Judul: Optimasi Penggunaan Koagulan Terhadap Rancangan Unit Koagulasi, Flokulasi, dan Sedimentasi pada Pengolahan Air Limbah Laboratorium
Abstrak: Laboratories wastewater of Bogor Agricultural University (IPB) Dramaga is one of the parties who contribute environmental pollution. Waste Water Treatment Plant (WWTP) located in front of the Veterinary Medicine Faculty serves to treat wastewater in order that appropiate with the treshold. The systems which is used in WWTP IPB is coagulation, flocculation, sedimentation, filter system (sand filters and carbon filters), and disinfection. The objective of this research is to analyze the characteristics of laboratiories wastewater, optimization of using coagulants, and designing coagulation-flocculation and sedimentation units, along with making the mass balance. This study done in two stages, the first stage was primary and secondary data collecting and the second stage was wastewater characteristics analyzing, doing jar test, and design units. Based on the results, the parameters pH, N-NO2, NH3, H2S has met quality standards but TDS, COD, BOD, oil and grease do not meet the threshold . The final concentration of TDS, COD, BOD, and oil and grease in a row at 11273 mg /L, 3300 mg/L, 442 mg/L, and 181 mg/L. The optimum dose of coagulant that can be used for wastewater treatment lab was 6250 mg/L PAC + 62500 mg/L alum. The mass balance indicates that TSS concentration at efluent already under the threshold that is 93 mg/L, whereas BOD was still above the threshold which was 331.77 mg / L. On coagulation and flocculation unit, stirrer speed does not meet the criteria. On sedimentation unit, BOD can be reduced up to 48 % and TSS reduction can be up to 70 %.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf