Projections for Indonesia's Future Waste Management: Production of RDF and Biochar Enriched Compost

Photo taken from here

The MSW problem is a concern in a number of areas currently. This is because MSW, apart from being a serious environmental problem, also has an impact on social problems. The public is starting to become more aware of this MSW problem, especially for urban communities who no longer have land to pile up or burn their MSW and what's more, final disposal sites are no longer able to accommodate the MSW produced by these communities. Flooding, groundwater pollution, air pollution are some of these environmental problems which, if not addressed, will cause a number of serious environmental problems. Public awareness regarding waste should be getting better day by day, and various efforts should be made to overcome it.

One of the composting unit in Indonesia

Currently the central government and regional governments are working hard to overcome the waste problem namely this MSW. Despite hard efforts, generally only a small portion of the MSW can be handled and most of it is still accumulating and accumulating so that it continues to pile up. An example is the current MSW problem in Jakarta, the capital of Indonesia namely with an average daily waste volume of 7,500 tons/day, only around 1,000 tons per day can be processed. With the RDF production unit at Bantar Gebang TPST, with raw materials of 2,000 tons of waste per day originating from 1,000 tons of new MSW and 1,000 tons of old waste (landfill mining), approximately 700 tons/day of RDF is produced. So with only 1,000 tons/day of new waste that can be processed, that means only 13% of the total daily waste volume. Meanwhile, conditions in a number of regions in Indonesia are also almost the same.

Future MSW processing must be able to process the 100% of MSW or have zero waste. Apart from that, the MSW processing product must also have useful and economic value. One of them is large capacity RDF and compost production. Almost all organic waste can be composted, while non-organic waste, especially plastic, can be made into RDF. Other waste such as iron, glass, ceramics and metals are separated first so that it does not interfere with the RDF and compost production process. RDF is commonly used as an alternative fuel, especially in cement plants. However, with high chlorine content, the use of RDF in cement plants needs to be limited.

Sometimes the distance between RDF production and the cement plant makes transportation costs expensive and RDF products become uncompetitive. This means that RDF needs to be compressed into RDF pellets. By increasing the density of RDF into pellets, apart from saving transportation costs, it will also make handling, storage and use easier. Meanwhile, biochar can be added to compost to improve its quality. Biochar is added during the composting process and later there will be more nutrients contained in the compost. Biochar with its micro pores will be used as a place to store these nutrients. Apart from that, biochar is used as a carbon sink / carbon sequestration and can survive in the soil for hundreds or even thousands of years. This also has the potential to provide additional income from carbon credits. Biochar production by pyrolysis will also produce heat energy which can be used for drying waste in RDF production and pyrolysis of organic materials.   

Model Semi-Kontinyu Produksi Arang Tempurung Kelapa

Produksi Arang Tempurung Tradisional

Rendahnya kualitas arang tempurung kelapa membuat pemanfaatan menjadi produk turunan selanjutnya menjadi terbatas dan terkendala. Sebagaian besar produksi arang tempurung kelapa masih dilakukan secara tradisional bahkan banyak yang tidak menggunakan kaidah yang benar seperti menyiram air untuk memadamkan arang yang masih berupa bara api. Salah satu produk turunan arang tempurung yang memiliki kualitas dan nilai tambah yang tinggi adalah untuk produksi arang aktif (activated carbon).  Ada lebih dari 150 varian arang aktif dan penggunaannya sangat luas pada berbagai industri. Sebagai negara dengan luas kebun kelapa terluas di dunia, tentu, sebuah peluang yang sangat menarik dan masih sangat terbuka.

Produksi arang aktif dimulai dari bahan baku arang yang berkualitas. Kualitas arang yang tinggi dibuat dari bahan baku memenuhi standar dan proses produksi modern. Pengaturan kondisi operasi berupa suhu, waktu tinggal dan kecepatan pemanasan adalah sejumlah variable proses yang harus dilakukan dengan mudah untuk menghasilkan produk yang standard dan stabil. Untuk mencapai kualitas produk yang diinginkan juga dilakukan dengan pengaturan kondisi proses. Efisiensi energi dan konversi ke produk yang  tinggi adalah parameter untuk tercapainya derajat keekonomian proses produksi yang tinggi.

Sementara proses batch telah banyak dilakukan, dibawah ini skema proses produksi arang tempurung kelapa secara semi-kontinyu, sebelum meningkat ke proses kontinyu.  Sumber panas dihasilkan dari gasifikasi sekam padi. Hal ini karena sekam padi banyak tersedia di berbagai tempat dan masih dianggap limbah sehingga belum dimanfaatkan. Seluruh uap dari hasil pirolisis di recycle sebagai sumber bahan bakar di tungku bersama gas dari gasifikasi sekam padi. Pirolisis dengan sistem indirect heating memungkinkan proses yang terjadi benar-benar tanpa oksigen atau hampa udara. Pada akhir proses akan didapat produk berupa produk utama berupa arang tempurung kelapa dari proses pirolisis dan arang sekam sebagai produk samping dari proses gasifikasi. Kualitas dan kuantitas arang yang dihasilkan dari gasifikasi juga berbeda dengan arang dari proses pirolisis karena kondisi operasi dan adanya oksigen pada proses gasifikasi.