3.3. TOSS : Local waste processing unit
Recently, a new invention of waste treatment that can be carried out by ordinary people in their own communities was declared by the School of Technology in Jakarta, STT PLN. This local waste processing unit has a copy right name , TOSS, which logo was patented as shown in Figure 3. TOSS is originated from Indonesian language, like for instace the Japanese original name for Kaizen in management field or Osaki in the waste treatment field.
Although there have already some waste to energy methods including incenerator, digester, gasifier, and pyrolisis, such technologies are still challenged by several problems including high capital expense and the large required processing area, which is usually conducted in the landfil ,. For example, there are at least two projects, one in Bali and another in Bekasi, that were failed because the process was depending on available methane gas from landfil, while in reality was not sufficient. Even worst, such digester concept could not solve the piled of remaining waste because it took only the gas produced by organic waste, not the solid waste. As the intention to solve municipal waste problems in many big cities, around two years ago, the government of Indonesia declared large scale waste to energy projects to convert waste in the landfill to become electricity in 12 big cities. But until recently, none of those expensive projects have been started, because PLN as offtaker company has not agreed to the price offered by the investors. Similarly, the local governments are also reluctance to the proposed tipping fee.
Actually, TOSS as a simple and people friendly way of local waste treatment unit can be used as an alternative to solve that problem ,,. As shown in Figure 1, the TOSS process begins with collecting valuable waste such as bottle, box, and can that has valuable selling price that can be sold for additional income. Then, put the waste into 2m x1m x1 m bamboo container and spray it layer by layer using special made bioactivator to reduce waste moisture, waste odor, and to create increas the calory. After the bamboo box full, then cover it by plastic sheet and keep it for about a week and control the waste temperature to comfort the bactery (should be more than 40 o C but could not exceed 70 o C).
After 3 days the waste has already died, no more odor and the volume will be reduced about half, but keep it in the bamboo until 7 to 10 days before crushing it using shredded machine. The shredded waste is then screened before put it into briqupellet machine. Now the pellet or briquette is ready to be used as biocoal for the heating or electricity generation purpose. The TOSS pellet has been tested several times in the laboratory and reported that the gross calorific value of the TOSS pellets are vary around 2800 to 3200 kcal/kg.
STT PLN has undertaken pilot project of TOSS at Pondok Kopi and Duri Kosambi Jakarta and since January 2018, TOSS has been implemented at Klungkung District. The project has successfully generated electricity using 15 kW Yanmar diesel genset and 30 HP Trilion gasifier feeding by TOSS pellet produced by Klungkung village people. Unlike previous way that must send waste to the landfill, TOSS can treat municipal waste in their own place. Therefore TOSS can eliminate the frequency of waste truck to the landfill. In addition, TOSS is different from other small scale waste treatment that needs to separate organic and non organic waste, TOSS needs no preliminary sorting and can solve the plastic and other non organic could process the whole mix waste .