The removal of calcium mineral deposits from metal surfaces is of practical interest for a variety of fields (i.e., food, petroleum, and chemical industries). This study investigated the mechanisms of calcite (CaCO3) dissolution using environmentally benign polyaspartic acid (PASP) under controlled hydrodynamic conditions by a rotating disk technique. The specific role of PASP conformation and surface interactions in the dissolution process was further studied using scanning electron microscopy and dynamic light scattering techniques. Using this combined approach, the dissolution mechanisms were investigated as a function of pH (3.5-10.0), rotating speed (150-1500 rpm), polymer concentration (0.001-0.1 M), and molecular weight (3000 and 10000 M-w). To quantify the effect of PASP on enhancing calcite dissolution, an enhancement factor, eta(enh), was defined as a ratio of the rate of dissolution in PASP over the rate in water. Maximum enhancement was observed at pHs in the range 4-5, where an optimal combination of acid attack and chelant attack may appear. Dissolution is governed primarily by interfacial phenomena, including adsorption and surface reactions, at high pHs (> 7), while it is controlled by mass transport at low pHs (< 7). Increasing polymer concentration under acidic pH conditions, or increasing pH, raises the contribution of the interfacial controlled dissolution mechanism. Dissolution at high pHs is inhibited by small amounts of PASP (0.001-0.01 M) and enhanced by large quantities (0.1 M) of PASP, and proceeds via a surface complexation mechanism involving the chelation of calcium by PASP. A kinetic model incorporating surface adsorption and sequestration chemistry was developed to successfully calculate the dissolution kinetics of calcite at pHs above 7. In contrast, dissolution at low pHs occurs predominantly by acid attack from all acidic species (including H+ and all partly dissociated PASP species), and PASP enhances dissolution over the entire concentration range (0.001-0.1 M). The lower molecular weight (3000) PASP is the more efficient dissolving agent at low pHs than the higher molecular weight (10000) PASP. Dissolution at low pHs represents the most complicated case. An analysis of the dissolution mechanisms at low pHs was conducted on the basis of the consideration of mass transfer, polymer surface adsorption, conformation of polymers, and surface interactions.