The tunnel composting method, in which combustible garbage and food scraps are fermented into fertilizer and fuel without being burned, seems to be able to remove mercury easily.

https://www.city.ichinoseki.iwate.jp/kouiki-gyousei/imagem/files/1653038875_14.pdf

Fast composting maintains good aerobic fermentation conditions by continuously or intermittently applying forced ventilation and mechanical turnover to food scraps. Figure 8.

Figure 8 Image of high-speed composting technology.

Once the raw garbage is processed in the primary fermentation tank, odors are removed by a deodorizer, and then it is processed in the secondary fermentation tank and separated into compost and unsuitable materials by a sorting machine.

生ごみを一次発酵槽で一旦処理して匂いは脱臭装置で取り除き、次に二次発酵槽で処理して選別機で堆肥と不適物に分けます。