Judul: Design of Wastewater Treatment Plant for Frozen Cilok Production Process at PT Karya Baru Kita
Abstrak: Air limbah industri makanan yang tidak ditangani dengan tepat dapat mencemari lingkungan. Penelitian ini bertujuan untuk merancang Instalasi Pengolahan Air Limbah (IPAL) untuk mengelola 1,5 m³ limbah cair per hari dari produksi cilok beku di PT Karya Baru Kita. IPAL yang dirancang mencakup beberapa tahap pengolahan secara batch, dengan unit-unit yang dirancang yaitu bak penampungan awal, tangki koagulasi-aerasi, bak aerasi, bak sedimentasi, dan bak pengeringan lumpur dengan waktu proses untuk setiap unit berturut-turut adalah 1 hari, 35 menit, 1 hari, 1 hari, dan pengeringan lumpur dengan ketebalan 40 cm diasumsikan memakan waktu 15 hari. Rancangan ini mampu menurunkan parameter Chemical Oxygen Demand (COD) hingga 99% dan Total Suspended Solids (TSS) sebesar 82%, memenuhi baku mutu yang berlaku. Analisis finansial menunjukkan bahwa penerapan IPAL ini memiliki perkiraan biaya operasional sebesar Rp3.815.325 per bulan. Perhitungan biaya ini sudah memperhitungkan peningkatan skala produksi perusahaan, sehingga dapat menjadi solusi jangka panjang yang efektif dan efisien bagi perusahaan yang sedang berkembang pesat dalam mengelola limbah cairnya., The discharge of untreated wastewater from the food industry significantly pollutes waterways, reducing oxygen levels and harming aquatic life. This study aims to design a wastewater treatment plant (WWTP) specifically tailored for treating 1.5 m³ per day of wastewater generated from frozen cilok production, an Indonesian street food. The designed WWTP includes several stages and units of batch processing, namely equalization tank, coagulation-aeration tank, aeration tank, sedimentation tank, and sludge drying bed with process times for each unit respectively being 1 day, 35 minutes, 1 day, 1 day, and 15 days to dry sludge with a thickness of 40 cm. This design is able to reduce Chemical Oxygen Demand (COD) parameters by up to 99% and Total Suspended Solids (TSS) by 82%, meeting applicable quality standards. Financial analysis shows that implementing this WWTP has an estimated operational cost of IDR 3,815,325 per month. This cost calculation takes into account the increase in the company's production scale, therefore proving that it can be an effective and efficient long-term solution for the company that is growing rapidly in managing their wastewater.
Keyword: Cilok, Food industry wastewater, Wastewater treatment plant (WWTP)

Judul: Design of Frozen Cilok Production Wastewater Treatment Process at PT. Karya Baru Kita.
Abstrak: Limbah cair merupakan permasalahan yang dihadapi setiap industri, salah satunya PT. Karya Baru Kita. Hal ini dapat menimbulkan dampak negatif, seperti menghasilkan bau tidak sedap, meningkatkan biaya operasional, dan mencemari lingkungan. Penelitian ini bertujuan untuk mengidentifikasi karakteristik limbah cair yang dihasilkan oleh PT. KBK, merancang proses pengolahan limbah cair yang sesuai sehingga memenuhi baku mutu, serta menganalisis efektivitas dari proses pengolahan yang dilakukan. Berdasarkan karakteristiknya, dirancang proses pengolahan yang menggabungkan beberapa metode pengolahan seperti metode kimia, fisika, dan biologi. Proses koagulasi menggunakan Poly Aluminium Chloride dengan dosis 40 ppm, serta proses aerasi dengan penambahan EM4 sebanyak 0,4% terbukti dapat menurunkan parameter COD dari 27.631 mg/L menjadi 41 mg/L (removal efficiency 99,85%) dan menurunkan parameter TSS dari yang semula 1064 mg/L menjadi 187 mg/L (removal efficiency 82,42%). Proses pengolahan yang dirancang menghasilkan effluent air limbah yang memenuhi baku mutu ditetapkan, artinya limbah cair sudah aman untuk dibuang ke lingkungan., Liquid waste is a problem faced by every industry, one of which is PT Karya Baru Kita. This can have a negative impact, such as producing unpleasant odors, increasing operational costs, and environmental pollution. This study aims to identify the characteristics of liquid waste generated by PT KBK, design a suitable liquid waste treatment process so that it meets quality standards, and analyze the effectiveness of the treatment process carried out. Based on its characteristics, a treatment process is designed that combines several treatment methods such as chemical, physical, and biological methods. The coagulation process using Poly Aluminum Chloride with a dose of 40 ppm, as well as the aeration process with the addition of EM4 as much as 0,4% proved to be able to reduce COD from 27.631 mg/L to 41 mg/L (removal efficiency 99,85%) and TSS from 1064 mg/L to 187 mg/L (removal efficiency 82,42%). The designed treatment process has produced wastewater effluent that meets the established quality standards, meaning that the wastewater is safe to be discharged into the environment.
Keyword: EM4, aeration, coagulation, PAC

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.
Keyword: