Judul: Utilization of Solid Waste from Broiler Cultivation at PT Sumber Agro Semesta Tanjungsari Bogor Regency
Abstrak: Limbah padat hasil budi daya ayam pedaging di PT Sumber Agro Semesta dijual langsung ke pembeli dengan harga yang relatif murah. Pengomposan menjadi salah satu alternatif pemanfaatan limbah padat yang dapat meningkatkan nilai tambah produk. Tujuan proyek ini adalah mengidentifikasi sumber terbentuknya limbah dan banyaknya limbah yang dihasilkan pada proses budi daya ayam pedaging, menganalisis formulasi pengomposan dan kualitas kompos dari limbah budi daya ayam pedaging, serta memberikan gambaran analisis biaya pengomposan skala laboratorium. Banyaknya limbah padat yang dihasilkan yaitu 56.000 kg dengan komposisi 64% sekam padi dan 36% kotoran ayam. Pengomposan yang dilakukan menggunakan metode dekomposisi aerob dengan formula 3 kg limbah padat dan 2 kg kotoran kambing. Parameter yang diamati selama proses pengomposan yaitu kadar air, suhu, dan rasio C/N. Rasio C/N awal yang ditetapkan sebesar 35, produk akhir kompos memiliki rasio C/N 17,25, kadar air akhir 42,05%, dan suhu akhir yaitu 28,33oC. Produk kompos selanjutnya dianalisis mutunya berdasarkan standar mutu SNI 19-7030-2004. Analisis biaya skala laboratorium yang digunakan yaitu perhitungan Harga Pokok Produksi (HPP) adalah Rp. 1.580,-/kg., Solid waste from broiler cultivation at PT Sumber Agro Semesta is sold directly to buyers at relatively low prices. Composting is an alternative to solid waste that can increase the added value of the product. The purpose of this project is to identify the sources of waste and waste generated in the broiler farming process, to analyze the composting formulation and organic quality of broiler farm waste, as well as to describe the cost analysis of laboratory-scale composting. The amount of solid waste produced is 56.000 kg with a composition of 64% rice husks and 36% chicken manure. Composting was carried out using the aerobic decomposition method with the formula 3 kg of solid waste and 2 kg of goat manure. Parameters observed during the composting process were air content, temperature, and C/N value. The initial C/N value was set at 35, the final compost product had a C/N value of 17,25, the final moisture content was 42,05%, and the final temperature was 28,33oC. The compost product is then analyzed based on the quality standard of SNI 19-7030-2004. Laboratory-scale analysis used is the calculation of the Cost of Production is Rp. 1.580,-/kg.
Keyword: C/N Value, Composting, Solid Waste, Temperature, Water Content

Judul: Co-composting Process Engineering Design of Sludge and Boiler Ash PT Tanjungenim Lestari Pulp and Paper using Windrow Composting Method.
Abstrak: PT Tanjungenim Lestari Pulp and Paper menghasilkan limbah sludge (30 ton/hari) dan abu ketel (33,3 ton/hari). Penanganan limbah saat ini menggunakan metode sanitary landfill. Salah satu alternatif pemanfaatan limbah adalah melalui proses co-composting. Penelitian ini bertujuan untuk menganalisis karakteristik sludge dan abu ketel, mendesain teknik proses co-composting dan menganalisis mutu produk kompos berdasarkan SNI-7847:2012. Penelitian ini merupakan penelitian faktor tunggal dengan metode windrow composting berskala 500 kg dan menggunakan komposter kayu berukuran panjang 100 cm, lebar 80 cm, dan tinggi 70 cm. Rasio C/N awal ditetapkan senilai 30, komposisi bahan senilai 2:1 (sludge 333 kg : 167 kg abu). Co-composting dilakukan selama 32 hari dengan pembalikan setiap 3 hari sekali. Fase termofilik tercapai dengan suhu 51 oC. Karakter fisik kompos sesuai dengan SNI-7847:2012, dengan warna hitam dan aroma seperti tanah. Kadar air akhir kompos adalah 46,31%, pH kompos 6, dan rasio C/N produk kompos 15,64. Kompos tidak mengandung Coliform fecal dan Salmonella sp. Kandungan logam berat kompos berada dibawah baku mutu. Bobot akhir produk kompos sebesar 365,5 kg dengan rendemen 69,5%., PT Tanjungenim Lestari Pulp and Paper produced sludge waste (30 tons/day) and boiler ash (33.3 tons/day). The current waste management method used sanitary landfill. One alternative for waste utilization was through the co-composting process. This study aimed to analyze the characteristics of sludge and ash, design co-composting process engineering, and analyze the quality of compost product based on SNI-7847:2012. This study was a single-factor research using the windrow composting method on a scale of 500 kg and used a wooden box composter with dimensions of length 100 cm, widht 80 cm, height 70 cm. The initial C/N ratio was set at 30, the material composition of 2:1 (sludge 333 kg : 167 kg ash). Co-composting was carried out for 32 days with turning every 3 days. The thermophilic phase was reached at a temperature of 51 oC. The physical characteristics of the compost complied with SNI-7847:2012. With a black color and soil-like aroma. The final moisture content of the compost was 46.31%, the pH was 6, and the C/N ratio of the compost product was 15.64. The compost did not contain Coliform fecal and Salmonella sp. The heavy metal content of the compost was comply to the quality standards. The final weight of the compost product was 365.5 kg with a yield of 69.5%.
Keyword: abu ketel, co-composting, sludge, windrow

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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