Trench hedge fund is a special investment tool, and its operation mode is different from traditional hedge fund. Trench hedge funds invest in sewage treatment, environmental treatment and other related industries in order to gain capital appreciation. Although the income of trench hedge funds mainly comes from capital appreciation rather than interest, in practice, investors may get some interest income according to the fund contract. These interest income may come from bonds and fixed income products invested by the fund. Therefore, trench hedge funds can earn interest to a certain extent.