The textile industry in Indonesia has increased since the 1980s. From the non-oil and gas sector, the textile industry is the government's largest source of income. In addition to its impressive growth, about 10-15% of the used textile dyestuff is wasted at the dyeing process can exceed the maximum Chemical Oxygen Demand level of 150 mg/L. Synthetic dyes contain carcinogenic ingredients that can harm the environment and aquatic biota. The alternative for handling the dye waste is the adsorption method using bio adsorbent from a mixture of chicken eggshells and rice husk ash. Both have the potential to be used as adsorbents because they have an active site, abundant amounts, and are economical. This study was to determine the effect of the process variables of the adsorbent mass ratio, contact time, and pH on the adsorption capacity of methylene blue using a mixture of eggshells and rice husk ash with the UV-Vis Spectrophotometer analysis method. The results showed that the optimal conditions for the adsorption of 20 ppm methylene blue were 0.2:0.8 gram of adsorbent ratio, 80 minutes, and pH of 3. The adsorption capacity obtained was 98.817%, reduced the methylene blue concentration to 0.237 ppm.

Abstrak: Pada saat ini masih banyak pekerjaan pertanian yang menggunakan tenaga pekerja dalam melaksanakan kegiatan produksi dan menyelesaikan proses setelah produksi tanaman jeruk diantaranya proses penyortiran buah. Penyortiran buah merupakan tahap pemisahan buah hasil panen berdasarkan tingkat kematangan buah, ditandai dengan perbedaan warna buah jeruk. Tingkat kematangan pada buah jeruk dibagi menjadi 3 tingkatan, yaitu: hijau, hijau kekuning-kuningan dan kuning. Warna hijau biasanya memiliki kandungan rasa yang asam, warna hijau kekuning-kuningan memiliki karakteristik rasa yang manis disertai dengan sedikit rasa asam dan memiliki kandungan banyak air, sedangkan warna kuning memiliki rasa yang manis. Pengelompokan buah jeruk pada beberapa industri pertanian saat ini masih dilakukan dengan cara konvensional. Proses ini memiliki kekurangan karena manusia memiliki keterbatasan dalam waktu pengerjaan dan berpikir serta seringkali merasa jenuh atau lalai ketika melakukan kegiatan penyortiran dalam waktu yang lama. Perancangan sistem yang berbasis mikrokontroler ATmega 328P dapat membantu meringankan pekerjaan manusia sebagai pengatur alat pemisah buah berdasarkan warna yang dilengkapi dengan sensor photodioda sebagai pemilih warna serta motor servo sebagai pemisah. Kata kunci: Jeruk, Mikrokontroler ATmega 328P, Pemisah Kematangan Buah, Sensor Photodioda. Abstract: At present there are still a lot of agricultural works that use workers in carrying out production activities and completing the processes after the production of orange crops such as fruit sorting process. Fruit sorting is the stage of separation of the fruit of the harvest based on the fruit maturity level, characterized by the color difference of orange fruit. Level of maturity in orange fruit is divided into 3 levels, i.e., green, yellowish green and yellow. The green color usually has a sour taste, yellowish green color has a sweet taste characteristics accompanied by a little sour taste and has a lot of water content