The problem of waste has to be tackled at the source, built on awareness, shaped into habit, and instilled from the classroom onward. This is where young people play a crucial role. In the right hands, students can become agents of change who shape environmentally friendly lifestyles for the future.

That understanding formed the basis for UIN Sunan Kalijaga Yogyakarta's Batch 120 KKN (Community Service Program) Team as they led a hands-on session on turning organic household waste into liquid organic fertilizer (POC) at SMAN 1 Sintang, West Kalimantan, on Friday, August 7, 2026. Targeting students was a deliberate choice, since behavioral change is most effective when it begins early, while habits are still easy to shape.

Around 250 students took part in the activity, held as part of a collaboration between UIN Sunan Kalijaga's KKN Team and the school, integrated into SMAN 1 Sintang's P8 Program. The program was designed to offer not just conceptual understanding, but also hands-on experience in managing waste responsibly.

KKN Team Leader Mufid explained that over the three weeks of the program, the approach was carried out in stages. In the first week, the team began with outreach on waste sorting, followed by “Operasi Semut” (Operation Ant), a simple movement aimed at building awareness of keeping the school environment clean.

By the second week, Mufid said, the activities moved into a more applied phase. Outreach on sorting valuable plastic bottles served as an entry point for introducing students to the concept of a circular economy. In this session, Mufid emphasized that plastic waste holds economic value when managed properly.

“Plastic bottles should be sorted by part: the cap, the label, and the body of the bottle. They also need to be clean and free of any leftover drink residue to fetch a better price when sold to waste collectors,” he said.

After the sorting of inorganic waste, the program moved on to making use of organic waste through a hands-on session on producing liquid organic fertilizer. Another member of the KKN team, Almuhajirin, explained the basic concept behind POC as a simple solution for managing household waste.

“The tools and materials used are fairly simple and easy to find. The equipment includes scissors, glue, used gallon containers, used bottles, and a hose. The main materials come from everyday waste, such as rice-washing water, vegetable scraps, and fruit peels, which are then combined with EM4 and molasses to support the fermentation process,” he explained.

The process begins with assembling a simple fermentation device using used gallon containers and bottles connected by a hose that serves as a gas outlet. Participants then poured in one liter of rice-washing water, along with four bottlecaps' worth of molasses and four bottlecaps' worth of EM4. The mixture was stirred and left to sit for about 15 minutes before the chopped organic waste was added.

Next, another roughly two liters of rice-washing water were added, and the entire mixture was shaken until well combined. The liquid organic fertilizer was then left to ferment for about two weeks before it was ready to use.

“Proper care during the fermentation process matters a lot. The container must not be exposed to direct sunlight, should be stored in a shaded spot, and needs to be shaken every day for the process to work optimally,” he added.

The work carried out by UIN Sunan Kalijaga's KKN team aligns with the Sustainable Development Goals (SDGs), particularly SDG 12 on responsible consumption and production. Teaching students to sort waste and turn organic waste into liquid organic fertilizer shows that environmental solutions don't always require complex technology; they can start with everyday practices relevant to the local context.

At first glance, waste is often seen as a minor part of daily life. But as it accumulates over time, it turns into a far more serious environmental problem. It is in this context that the involvement of UIN Sunan Kalijaga's KKN team finds its relevance, showing up through steps that may seem small, but that are grounded in practices close to everyday life.

This kind of approach opens space for new habits to grow in how people view and manage waste. And it is here that higher education plays its part, joining the broader, shared effort to break down waste and turn it into something of value. (humassk)