Effect of Activated Sludge, Which Is Produced by the Treatment of Waste Water at a Chemical Factory, on Chinese Cabbage

The manuring effects of the activated sludge, which is produced from the waste water at a chemical factory, were studied on the growth of chinese cabbage. The results obtained were as follows. (1) The yield of chinese cabbage increased with the increasing amount of applied activated sludge up to 1977 kg/10a. (2) Addition of perlite to the wet activated sludge brought not only the decrease of stickness of the activated sludge, but also the yield increase of chinese cabbage. (3) The most part of nitrogen in the activated sludge was slow-release nitrogen compounds, but NH_4-N and NO_3-N might be also cintained in a small portion. (4) The examined activated sludge contained very little cmount of heavy metals, and its application to chiese cabbage did not result in the absorption increase of heavy metals. (Received June 30, 1977)