Kinetic Study on Coagulation Process with Poly Aluminium Chloride and Alum Coagulants in Treating The Liquid Waste of Tempeh Industry

Several factors that influence the coagulation process in reducing chemical oxygen demand (COD) in wastewater are processing time, coagulant dose and type of coagulant. The effect of these three factors on the reduction of COD in tempeh industrial wastewater during the coagulation process has been investigated by Hidayah (2018). However, kinetic studies in depth have not been done by Hidayah (2018). Therefore, the aim of this study was to develop a new kinetic model that can predict the performance of the coagulation process. It is hoped that the kinetic model can be used in a wider range of operating conditions. In this study, the pseudo first order and pseudo second order kinetic models were tested to get the best model. Based on simulation results, both models produced almost the same accuracy. For reason of simplification, the pseudo first order model was chosen as the basic model in this study. Furthermore, modifications were made to the pseudo first order model so that the effect of processing time, coagulant dose and type of coagulant appeared in the model. This kinetic model was successfully tested to predict the coagulation performance of study of Hidayah (2018) with an average Mean Absolute Percentage Error (MAPE) of 10.8%

Study of the Potential Anaerobic Co-digestion for Biogas Production From Salvinia Molesta and Rice Straw

The purpose of this research was to analyze the biogas production from co-digestion of Salvinia molesta and rice straw. Ratio of Salvinia molesta and rice straw was 5:0, 4:1, 3:2. Lab-scale-batch digesters (600 mL) were operated at room temperature (30 oC) and pressure of 1 atm. Total basis of Salvinia molesta and rice straw was 10 gr, water was added with ratio of organic matter:water = 1:7 (w/w), rumen fluid was added as inoculum, initial pH was adjusted to be 7. Fermentation process was conducted for 30 days. The results showed that total biogas volume for ratio of 5:0, 4:1, 3:2 was 6.30±0.00; 32.76±18.32; 107.54±18.51 mL/g VS respectively. The pH of substrate was changing from 7.00 to 6.77±0.19; 6.60±0.14; 6.73±0.09 for all variables respectively

Co-Digestion of Vinasse Waste and Tofu Liquid Waste to Increase Biogas Production

The purpose of this study was to increase biogas production using co-digestion concept. Vinasse Waste (VW) containing high COD and low total Nitrogen content was mixtured with Tofu Liquid Waste (TLW) containing low COD and high total Nitrogen. Substrates were varied with volume ratio of VW:TLW of 100:0, 20:80, 0:100. Total volume of substrates was 250 mL. Anaerobic digesters were operated at room temperatur. After fermentation, biogas total volume of variables of 100:0, 20:80, 0:100 was 88.5; 125.5; 41.5 mL. Initial pH for all variables was 7.0. At the end of fermentation, pH substrates became 3.9; 5.1; 6.8 for variables of 100:0, 20:80, 0:100 respectively

Effect of Fe Addition on Anaerobic Digestion Process in Treating Vinasse: Experimental and Kinetic Studies

Vinasse is a continuously resulting waste by a bioethanol industry with a high chemical oxygen demand (COD) concentration and a large volume. Anaerobic digestion (AD) is the best method to treat vinasse because it converts COD to biogas, so the biogas can support the Indonesia's primary energy need. The goal of this study was to study the effect of Fe concentration on the AD process in treating the vinasse. The Fe concentration was varied to 0.06, 0.29, 0.64, 0.99 g/L. The results showed that increasing the Fe concentration from 0.06 to 0.29 g/L intensified the biogas yield by 360% (from 10.8 to 49.6 mL/g COD). However, further increasing the Fe concentration to 0.99 g/L decreased the biogas yield by 37.8% (from 10.8 to 6.7 mL/g COD). The Fe significantly affected the methane formation stage, but not the acid formation stage. A mechanistic model was built and successfully applied to predict the AD process. Based on the simulation results, Fe concentration of 0.29 g/L resulted in the highest values of YVFA/X2 (yield of volatile fatty acids (VFAs) consumption per biomass of X2 ), μm,2 (specific growth rate for X2 ),  fCH4 (composition of methane in biogas) and the lowest values of Ks,VFA (affinity coefficient in VFAs consumption), kd2 (death rate constant for X2 ), kVFA (consumption rate of VFAs for maintenance). The addition of Fe until 0.29 g/L was recommended to increase the quantity and quality (methane content reached 53.4%) of biogas production

Study of Plate and Frame Heat Exchanger Performance : The Effects of Mass Flow Rate, Inlet Temperature and Type of Flow Againts The Overall Heat Transfer Coefficient

The purpose of this study is to know the effects of mass flow rate, inlet temperature and type of flow againts overall heat transfer coefficient (U). Heat exchanger used in this study was plate and frame type of TRIMGS 10. Mass flow rate of hot fluida was variated into 0.3 and 0.253 kg/s; mass flow rate of cold fluida was variated into 0.276 and 0.22 kg/s; inlet temperature of hot fluida was variated into 40, 45, 50 oC; type of flow was variated into co-current and counter current. The results show that the faster mass flow rate hot and cold fluida, the bigger overall heat transfer coefficient obtained. Also, the higher inlet temperature, the the bigger overall heat transfer coefficient obtained.  In this study, the biggest of U value was obtained with variable of inlet temperatur 50°C, mass flow rate of cold fluid 0.276 kg/s, mass flow rate of hot fluid 0.3 kg/s, which were 140.6532 W/m2°C using type of counter-current flow and 135.4576 W/m2°C using type of co-current flow. Type of counter-current flow gave more satisfactory result of U value than type of co-current flo

Konsep Dasar Berfikir Ilmiah dengan Penalaran Deduktif, Induktif, dan Abduktif

Every living thing in this world including humans and animals have a brain for them to think. Both humans and animals are able to produce knowledge, where knowledge is used to improve their quality of life. Basically animals have knowledge, but knowledge is produced through the process of thinking without reasoning, so the benefit is only very limited knowledge for survival. Human reasoning capabilities have led to human knowledge that developed far more advanced than in animals. Even human beings are the only creatures that develop knowledge in earnest on this earth. The man knows what is right and what is wrong, what is good and what is bad, and what a beautiful and what is not. Reasoning is a process to draw a conclusion in the form of knowledge. Reasoning generates knowledge that is associated with the activity of thinking rather than feeling. Nevertheless we should realize that not all of the activity of thinking relies on reasoning. So the reasoning is the thinking that has certain characteristics in finding the truth. There are various ways to do the reasoning, such as deductive, inductive, and abductive. Deductive reasoning logically draws conclusions from given premises. Note that deductive reasoning is a logical conclusion from the premises available. The result is not always the truth that we know. Inductive is generelizing a thing of the cases which we have ever seen or experienced to draw conclusions about other things that we have never seen or experienced. Abductive is reasoning from a fact to actions or conditions that result in fact occurred. This method is used to describe events that we observe

Pengaruh Perbedaan Jenis dan Konsentrasi Sumber Nitrogen (NaNO3 dan urea) terhadap Produksi Biomasa Spirulina Platensis

The goal of this study was to investigate the effect of the concentration and the type of nitrogen sources in the cultivation medium on the production of biomass and biochemical content (carbohydrates, proteins, fats) in the Spirulina platensis biomass. Types of nitrogen sources included NaNO3 and urea, where the concentrations were varied from 0.5 to 3.5 g/L. The results showed that the use of urea tended to produce more S. platensis biomass than the use of NaNO3. The best concentrations that produced the highest biomass were NaNO3 2.5 g/L (biomass 0.6745 g/L) and urea 0.5 g/L (biomass 0.7158 g/L). The use of urea also tended to produce a higher specific growth rate and a shorter doubling time than the use of NaNO3. The high concentration of nitrogen sources caused the pH of the medium to increase more rapidly due to the accumulation of ammonium in the medium. Using NaNO3 can produce biomass with a higher protein content (28.34-36.98%) than using urea (25.86-33.52%).Tujuan penelitian ini adalah menginvestigasi pengaruh konsentrasi dan jenis sumber nitrogen pada medium kultivasi terhadap produksi biomasa dan kandungan biokimia (karbohidrat, protein, lemak) dalam biomasa Spirulina platensis. Jenis sumber nitrogen meliputi NaNO3 dan urea, dimana konsentrasinya divariasikan 0,5-3,5 g/L. Hasil penelitian menunjukkan penggunaan urea cenderung menghasilkan biomassa S. platensis lebih banyak dibandingkan penggunaan NaNO3. Konsentrasi terbaik yang menghasilkan biomasa tertinggi adalah NaNO3 2,5 g/L (biomasa 0,6745 g/L) dan urea 0,5 g/L (biomasa 0,7158 g/L). Penggunaan urea juga cenderung menghasilkan laju pertumbuhan spesifik yang lebih besar dan waktu berganda yang lebih singkat dibandingkan penggunaan NaNO3. Konsentrasi sumber nitrogen yang tinggi menyebabkan pH medium dapat meningkat lebih cepat karena akumulasi ammonium di dalam medium. Penggunaan NaNO3 dapat menghasilkan biomasa dengan kandungan protein yang lebih tinggi (28,34-36,98%) dibandingkan penggunaan urea (25,86-33,52%)

Pengaruh Variasi Konsentrasi NaNO3 pada Medium Raoof terhadap Kultivasi Spirulina Platensis

Nutrition is one of the factors that affect the growth of Spirulina platensis. The cultivation medium proposed by Raoof is a modified version of Zarrouk medium. Raoof medium requires less nutrients than Zarrouk medium but the biomass produced is almost the same. This study was conducted to vary the concentration of NaNO3 of 0.5; 1.5; 2.5; 3.5 g/L in Raoof medium to study its effect on growth and biomass composition of S. platensis. At each concentration of NaNO3 of 0.5; 1.5; 2.5; 3.5 g/L obtained the highest biomass concentration of 0.6425; 0.6455; 0.6745; 0,5193 g/L on days 12, 12, 12, 10. Concentration of NaNO3 of 2.5 g/L resulted in the highest specific growth rate of 0.1371/day and the lowest double time of 5.0566 days. In general, increasing the concentration of NaNO3 from 0.5 to 2.5 g/L increased the protein content from 33.30 to 36.98%. The addition of higher NaNO3 (3.5 g/L) actually decreased the protein content to 35.52%.Nutrisi adalah salah satu faktor yang mempengaruhi pertumbuhan Spirulina platensis. Medium kultivasi yang diusulkan oleh Raoof adalah hasil modifikasi dari mudium Zarrouk. Medium Raoof membutuhkan nutrisi yang lebih sedikit dibandingkan medium Zarrouk tetapi biomassa yang dihasilkan hampir sama. Penelitian ini dilakukan untuk memvariasikan konsentrasi NaNO3 0,5; 1,5; 2,5; 3,5 g/L pada medium Raoof untuk mempelajari pengaruhnya terhadap pertumbuhan dan komposisi biomassa S. platensis. Pada masing-masing konsentrasi NaNO3 0,5; 1,5; 2,5; 3,5 g/L diperoleh konsentrasi biomassa tertinggi sebesar 0,6425; 0,6455; 0,6745; 0,5193 g/L pada hari ke-12, 12, 12, 10. Konsentrasi NaNO3 2,5 g/L menghasilkan specific growth rate tertinggi yaitu 0,1371 /hari dan double time terendah yaitu 5,0566 hari. Secara umum, peningkatan konsentrasi NaNO3 dari 0,5 ke 2,5 g/L meningkatkan kadar protein dari 33,30 menjadi 36,98 %. Penambahan NaNO3 lebih tinggi (yaitu 3,5 g/L) justru menurunkan kadar protein menjadi 35,52%