化池 meaning in Chinese

digestion tank
septic tank

In summer , using half - underground pool to have solid - state alcoholic fermentation . result showed : the temperature of half - underground pool was 2 - 3 lower than ground pool , the alcoholic strength proved 29 % , acidity descended 40 % , productivity of vinegar proved 5 . 17 %
夏季利用半地下酒化池进行固态法酒精发酵，结果表明：半地下池较地上池酒醅发酵温度下降2 3 ，酒醅酒度提高29 % ，酒醅酸度下降40 % ，食醋产量提高5 . 17 % 。