Employing Worms in Industrial Wastewater Treatment

Developing food chain-based wastewater treatment technology

Kao is striving to recycle resources, including water, at all its production sites, and is developing technology to reuse and recycle wastewater to achieve zero waste.

Harvesting the power of microbes to purify wastewater

The product manufacturing process uses large amounts of water. Kao is trying to use water at its plants as effectively as possible, and cleans wastewater so that it conforms to environmental standards when returned to oceans and rivers.
To achieve this, Kao is pursuing research into a wide range of wastewater treatment technologies. Recently, the Industrial Technology Center of Wakayama Prefecture developed food production wastewater treatment technology that utilizes the food chain. Through collaborative research, we are looking into applying the same technology in treating chemical wastewater.

In order to break down the organic matter in wastewater, microbes are used to purify the water. During the purification process, however, microbes tend to proliferate, resulting in the production of sludge.
To combat this, we have started installing into the wastewater sheets made from pile fabric, a specialty of Wakayama Prefecture, to act as a bed for sludge worms. These worms help to break down the microbes present in the water, thus dramatically reducing sludge production.

Researcher installing a sludge worm bed of pile fabric into a test plant

Lowering plant wastewater sludge output, as well as reducing environmental impact

Following an experiment using wastewater in the Wakayama Plant in 2016, sheets made of pile fiber were installed in actual wastewater treatment facilities at seven plants in Japan and overseas, and experiments were conducted to confirm the development and growth of sludge worms. The results showed that the sludge worm biological treatment process was heavily affected by the water temperature, so it was found that the water temperature conditions required are different to conventional treatment conditions.

In addition, it was confirmed that even when there was a decrease in sludge worm growth due to unexpected water temperatures outside of specified conditions, the growth could be resumed once conditions were restored.
As a result, it was concluded that this method can be applied to several existing factories.

Large-scale introduction of this technology will not only reduce final waste volume, but also reduce the cost of wastewater treatment.
Kao is continuing research with the goal of using this technology at plants both inside and outside Japan.

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