Basalt fiber is a material made of extremely fine fibers of basalt. It is used as a fireproof textile in aerospace and automotive industries. Recently, it was discovered that suspended solids in water are attached onto basalt fiber. An experiment was conducted on the adhesion efficiency of suspended solids (SS) present in the Johakasou effluents onto basalt fiber. The investigation was carried out to study the potential of basalt fiber in removing SS from the Johkasou effluents. The results of the batch test showed that SS were reduced to less than 1 mg/l after treatment in a sample whose concentration was 200 mg/l before treatment, and that the adhesion of SS on basalt fiber is a fast process. The results of immersing basalt fiber in the existing Johkasou system indicated that the SS and BOD decreased in the johkasou effluents. Furthermore, the Johkasou effluents achieved a stable improved quality that was less than the effluent quality target (BOD ≦20 mg/l, water transparency ≧30 degrees), and could be maintained for a long period. Therefore, the quality of the water treated with basalt fiber could be improved.