InfoSAWIT, JAKARTA – Behind the smoke stacks and palm oil waste ponds, a group of Indonesian scientists has birthed an innovation that could revolutionize the national palm oil industry. Utilizing a microorganism and aquatic plant-based approach, they have successfully developed a system to absorb the toxic gas hydrogen sulfide (H₂S) from palm oil mill effluent (POME), while simultaneously purifying wastewater for reuse and producing organic fertilizer.

This research, published in the journal Case Studies in Chemical and Environmental Engineering in 2025, is the result of collaboration among researchers from various institutions, including Bambang Trisakti, Rivaldi Sidabutara, Irvana, Gloria Clarita Sinamo, and others. The solution they propose does not rely on expensive technology or aggressive chemicals, but rather on two natural biological agents: the soil bacterium Thiobacillus sp. and the aquatic plant Azolla microphylla.

“Solutions to waste often lie right around us. We try to listen to nature,” said lead researcher Bambang Trisakti, as reported by InfoSAWIT from the official website of Universitas Sumatera Utara (USU) on Monday (July 14, 2025).

POME has long been recognized as a byproduct of the palm oil industry that emits a foul odor and causes pollution if not managed properly. However, this waste also contains biogas that can be harnessed as an energy source. Unfortunately, this biogas is often contaminated with H₂S—a toxic and corrosive gas that damages equipment and poses health risks.

Industries typically rely on chemicals to eliminate H₂S, but this method is costly and generates secondary waste. Here, the biological approach emerges as a more environmentally friendly and economical alternative.

The system developed by the research team utilizes a column filled with water and a structure known as a Raschig ring to absorb H₂S from biogas. The water is then regenerated through two stages: first, it is channeled into a pond containing Thiobacillus sp. bacteria to oxidize H₂S into sulfate compounds; second, it is directed to a pond with Azolla microphylla, a tiny aquatic plant capable of absorbing residual pollutants and improving water quality.

The results are promising: the concentration of H₂S in the water dropped drastically from 3000 ppm to 900 ppm within nine hours due to Thiobacillus sp., and then further reduced by Azolla from 10,000 ppm to just 1700 ppm over four days. The system's efficiency reached 83%.

Multi-Benefits in One System

Not only does this system clean the air and water, but it also produces biofertilizer from the growth of Azolla, which is rich in nitrogen and can be used as organic fertilizer. “In one pond, we gain benefits from three functions: pollutant absorption, oxygen production, and fertilizer provision,” explained Bambang.

Further laboratory tests have shown that this system can reduce biochemical oxygen demand (BOD), chemical oxygen demand (COD), and dissolved solids in wastewater, while also balancing the pH of initially acidic water to neutral.

The final water can be reused as technical water in factories or processed into liquid organic fertilizer. Even more interesting, the operational costs of this system are very low—around Rp54.8 per liter, far below its economic value, which can reach Rp709 per liter from the sale of biofertilizer and sulfur from oxidation.

A Solution for Industry, Hope for the Environment

Bambang emphasized that this technology is designed to be adopted even by small-scale palm oil mills. “We want to prove that sustainability can be affordable, simple, and still profitable,” he stated.

With broader implementation, this system could address the palm oil industry's significant challenge: how to manage waste without polluting the environment while generating added value from the process. It touches on three main pillars of sustainability—economic, social, and ecological—in a cohesive framework.

More than just a scientific achievement, this research story symbolizes that change can start from small beginnings. From a drop of wastewater and a handful of microbes, a system has emerged that can purify the air, enrich the soil, and clean the water.

In the future, as Indonesia's palm oil industry moves towards a greener and cleaner direction, we may look back at this simple laboratory—where the courage to think differently has transformed waste into wealth. (T2)