Fast composting of food waste using thermal composter

Composting is an effective method to treat food waste. If food waste can be reduced from households, the transportation process to landfills can be reduced, cheaper costs, and the amount of waste in landfills. In this study, an innovative composting device-thermal composter was developed to accelerate the composting of food waste at home. This study uses food waste in a mixture of Chinese cabbage (Brassica rapa subsp. pekinensis) and rice from a household in Semarang, Indonesia. Food waste was chopped, stirred, heated, and decomposed in a thermal composter. The composting was carried out for three days with moisture content, pH, electrical conductivity, volatile solids, C-Organic, N-Total, P-Total, K-Total, plant growth test (Vigna radiata). The results showed that the growth of Vigna radiata using compost on the third day was better than on the first day. Final compost quality has water content = 75.16%, pH = 7.09, electrical conductivity = 552 Scm−1, volatile solid = 76.45 %, C-Organic = 7.05%, N-Total= 0.433 %, P-Total= 0.147 mg P2O5/100 g, K-Total= 0.149 mg K2O/100 g. It indicates that food waste can be recycled into useful products on a household scale within three days.

RANCANG BANGUN DAN UJI KINERJA DIGESTER BIOGAS RUMAH TANGGA TIPE FLOATING TANK DENGAN SUBSTRAT KOTORAN SAPI

Digester biogas rumah tangga berpotensi menyediakan bahan bakar terbarukan pengganti LPG (liquefied petroleum gas). Penelitian ini bertujuan untuk merancang-bangun dan menguji kinerja digester biogas rumah tangga tipe tangki mengapung (floating tank) dengan substrat kotoran sapi. Penelitian dilakukan dengan membuat digester biogas tipe floating tank menggunakan sumur dangkal dari pasangan bata semen yang diplester (diameter-dalam 139 cm, kedalaman efektif 140 cm) sebagai digester dan tangki air kapasitas 2000 l sebagai penampung biogas. Ukuran digester didasarkan pada kebutuhan biogas untuk keperluan memasak rumah tangga dan potensi kotoran empat ekor sapi. Kinerja digester dievaluasi dari produksi biogas, komposisi biogas, dan kemampuan digester dalam mendekomposisi substrat yang dinilai dari penurunan kandungan padatan tak stabil (volatile solid, VS). Hasil penelitian menunjukkan bahwa pada suhu lingkungan rata-rata antara 26,97 ℃ (pagi) dan 31,97 ℃ (sore) digester bekerja pada pH rata-rata 7,7 dengan dekomposisi VS mencapai 56,3%. Dengan laju pengumpanan kotoran sapi cair 60 l/hari, produksi biogas dapat mencapai 1.300 l/hari dan produktivitas biogas mencapai 634,6 l/m3 volume aktif digester. Biogas yang dihasilkan memiliki kualitas medium dengan kandungan metana (CH4) mencapai 50,28% dan nilai kalori 18,01 MJ/Nm3. Lumpur digestat berpotensi sebagai pupuk organik dengan kandungan hara N 4,55%; P 2,16%; dan K 3,89%. Salah satu keunggulan yang sangat menonjol dari digester floating tank adalah desain yang sederhana, biaya terjangkau, dan diperkirakan akan awet, sehingga dapat dijadikan sebagai model untuk dikembangkan dan diadopsi.

Biomethane Yield, Physicochemical Structures, and Microbial Community Characteristics of Corn Stover Pretreated by Urea Combined with Mild Temperature Hydrotherm

The corn stover (CS)’s compact structure makes it challenging for microorganisms to use in anaerobic digestion (AD). Therefore, improving CS biodegradability has become a key focus in AD studies. Methods are being targeted at the pretreatment of CS, combining advanced urea with mild temperature hydrotherm pretreatment to study its effect on promoting the AD process of CS. The biomethane yield, physicochemical structure, and microbial community characteristics were investigated. CS samples were assigned into groups differed by a range of pretreatment times (from 24 to 96 h) and set at a temperature of 50 °C with a 2% urea addition. Results revealed that the 72-h group obtained the highest biomethane yield of 205 mL/g VS−1, volatile solid (VS) and total solid (TS) removal rates of 69.3% and 47.7%, which were 36.7%, 25.3% and 27.5% higher than those of untreated one, respectively. After conducting several analyses, results confirmed the pretreatment as a method for altering CS microstructures benefits biomethane production. The most resounding differences between pretreated and untreated groups were observed within a microbial community, an integral factor for improved AD performance. This study serves to confirm that this specific pretreatment is an effective method for enhancing biomethane production in CS.

Peningkatan Kualitas Biogas Melalui Proses Pemurnian Dengan Purifier Bertingkat Seri Menggunakan Adsorben Arang Aktif Dan Zeolit

Abstrak. Biogas merupakan gas yang dihasilkan dari bahan organik melalui proses fermentasi. Energi yang terkandung dalam biogas tergantung dari konsentrasi metana (CH4). Semakin tinggi kandungan metana maka semakin besar kandungan energi pada biogas. Salah satu cara untuk meningkatkan kandungan gas metana pada biogas serta dapat menurunkan gas-gas pengotor seperti CO2, dan gas-gas lain yang tidak terpakai dengan pemurnian menggunakan purifier yang telah di isi adsorben, pada penelitian ini adsorben yang digunakan yaitu arang aktif dan zeolit. Variabel yang diukur dalam penelitian ini yaitu C/N rasio, pH, suhu, total solid (TS), volatile solid (VS), Biochemical Oxygen Demand (BOD) dan Chemical Oxygen Demand (COD) yang berpengaruh dalam produksi gas metan. Kadar CH4 dan CO2 setelah dimurnikan, dan waktu optimal untuk proses pemurnian biogas, perlakuan yang diberikan menggunakan 3 waktu pengujian, yaitu 30, 60, dan 90 menit. Percobaan dilakukan pengulangan sebanyak tiga kali. Hasil penelitian menunjukkan bahwa rasio C/N sebesar 20,36 dengan suhu rata-rata 25,1oC dan pH rata-rata 6. Nilai BOD awal dan akhir masing-masing sejumlah 77800,86 mg/l dan 53002,42 mg/l dan COD awal dan akhir masing-masing sejumlah 59800 mg/l dan 36000 mg/l. TS dan VS masing masing mengalami penurunan sebesar 20,99% dan 17,93%. Penggunaan adsorben arang aktif dan zeolit dapat meningkatkan kandungan gas CH4 sebesar 136,5% dan menurunkan kandungan gas CO2 sebesar 64% pada biogas. Lama waktu pengujian mampu meningkatkan konsentrasi CH4 dan menurunkan kandungan gas CO2 dengan waktu paling optimal yaitu 30 menit.Increasing Quality Of Biogas With Purification Proses On Double Arranged Series Purifier Using Activated Charcoal And Zeolit AdsorbentAbstract. The quality of biogas is determined by the methane (CH4) content in the biogas. A good biogas is indicated by its high methane content. One way to increase the methane gas content in biogas is by purification using a series-level purifier that has been filled with adsorbents. In this study, the adsorbents used were activated charcoal and zeolite. The variables measured include CN ratio, pH, temperature, total solid (TS), volatile solid (VS), Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) which influential in methane gas production. CH4 and CO2 levels, before and after purification. Biogas was purified for a duration of 30, 60, 90 minutes and was repeated three times. The results showed that the C/N ratio was 20.36 with an average temperature of 25.1 °C and an average pH of 6. The initial and final BOD values were 77800.86 mg/l and 53002.42 mg/l and the initial and final COD values were 59800 mg/l and 36000 mg/l. TS and VS experienced a decrease of 20.99% and 17.93%. The use of activated charcoal and zeolite adsorbents was able to increase the CH4 gas content by 136.5% and reduce the CO2 gas content by 64%. The optimal purification time is 30 minutes.

Evaluation of Sludge Properties in Sewage Sludge from Guarchia Wastewater Treatment Plant in Benghazi-Libya

Raw sewage sludge samples collected from Guarchia wastewater treatment plant at Benghazi city have undergone complete evaluation of organic composition parameters including pH, Total Volatile Solid (TVS), Total Nitrogen (TN), Total Phosphorus (TP), Total Organic Matter (TOM) and Total Organic Carbon (TOC). Also, evaluation of some trace metals such as Zn, Cd, Cu and Pb have been performed. Monthly and spatial variations in sludge properties have been described.

Evaluation of Sludge Properties in Sewage Sludge from Guarchia Wastewater Treatment Plant in Benghazi-Libya

Raw sewage sludge samples collected from Guarchia wastewater treatment plant at Benghazi city have undergone complete evaluation of organic composition parameters including pH, Total Volatile Solid (TVS), Total Nitrogen (TN), Total Phosphorus (TP), Total Organic Matter (TOM) and Total Organic Carbon (TOC). Also, evaluation of some trace metals such as Zn, Cd, Cu and Pb have been performed. Monthly and spatial variations in sludge properties have been described

Thermophilic co-digestion of food waste and sewage sludge

Due to the rising concerns regarding food waste disposal as well as the increasing demand for renewable energy nowadays, a number of European countries have adopted anaerobic co-digestion, a technology that deals with food waste and sewage sludge. As stated in the HKSAR Government’s Policy Address 2016, the feasibility of using existing sewage treatment facilities for co-digestion of food waste and sewage sludge has been under exploration. A trial scheme has been commenced in 2019. This paper aims to compare the efficiency of biogas production and volatile solid reduction in co-digestion of food waste and sewage with mono-digestion in laboratory scale.

PENGARUH SUBSTITUSI BY-PRODUCT INDUSTRI TAPIOKA PADA FESES SAPI PERAH SEBAGAI SUBSTRAT BIOGAS TERHADAP NILAI pH, PRODUKSI METAN DAN KECERNAAN BAHAN ORGANIK

Tujuan dari penelitian ini adalah untuk mengevaluasi co-digesti onggok dengan feses sapi perah sebagai substrat pada digeter biogas terhadap nilai pH, produksi metan dan kecernaan bahan organik. Hasil penelitian menunjukan bahwa tidak adanya perbedaan yang nyata (p>0,05) antara perlakuan penggunaan onggok dan feses sapi perah sebagai substrat biogas (T1) dengan feses sapi perah tanpa substitusi dengan onggok (T0) terhadap nilai pH, produksi methan dan kecernaan bahan organik. Nilai pH pada perlakuan T1 sebesar 6,68 dan T0 sebesar 6,86. Produksi metan pada T1 sebesar 204,84 ml/g volatile solid (VS) dan pada T0 sebesar 184,88 ml/g VS. Kecernaan bahan organik pada T1 (29,44%) dan T0 (23,06%). Kesimpulan dari penelitian ini adalah substitusi onggok sebesar 5% pada feses sapi perah sebagai substrat biogas dengan bahan baku feses sapi perah tidak memberikan perbedaan terhadap nilai pH, hasil produksi metan dan kecernaan bahan organik. Kata kunci : Biogas, Kecernaan bahan organik, Nilai pH, Onggok, Produksi metan

Optimization of biogas from corn stover using liquid and solid-state anaerobic digestion

The shortage of fossil fuel can be minimized by developing renewable energies such as biogas. The raw material of biogas can be derived from corn stover. Biogas was produced under solid-state anaerobic digestion (SS-AD) and liquid anaerobic digestion (L-AD). The objectives of this study were to compare the biogas yield and analyze the pH value and VS degradation. The results reported that the SS-AD generated a higher biogas yield than L-AD. SS-AD could improve the biogas yield of 71%. Both SS-AD and L-AD had a higher final pH than the initial pH. Moreover, the VS degradation was proportionate to the biogas yield. The highest VS reduction was achieved on SS-AD. Keywords: anaerobic digestion, biogas, liquid state, solid state, volatile solid, renewable energy