Shells are waste products from mariculture that presents a major disposal problem in coastal regions in China. While based on previous researches, shells can be used as carrier in Aerobic Bio-filter (ABF). It was investigated in present research that the role of shell for wastewater pH adjustment and alkalinity releasing through static experiment. Under the wastewater and shell volume ratio of 9:1 and initial wastewater pH 7.25, 6.75, 6.25, 5.75 and 5.25, after 24 hours static contact, the experiment obtained 6.2%, 13.6%, 19.7%, 29.6% and 41.7% of pH increasing rates, and 27.4%, 62.9%, 143.3%, 461.3% and 670.45% of alkalinity increasing rates, individually. The laboratory-scale acidogenesis reactor with shell as biomass carrier for treating domestic wastewater was conducted. The experimental results showed that TP removal could be increased 100 percent over that of conventional soft carrier, getting 26% of averaged removal under 8 h of hydraulic retention time.