This study investigated the reduction of Pb(II)) by bioaccumulation and biosorption in an artificial biosorbent. The biosorbent was prepared by mixing grounded manure and fine-grain sand at a ratio of 1:1 (w/w) with the media packed into a laboratory scale column (diameter of 4.7 cm). The sweet soy sauce (food grade) solution with pH ranged of 5.0-5.5 and the concentration of 15 g COD L-1 was fed at a rate of 500 mL d-1 to the column surface for a period of 101 d. The active biofilm was then acclimatised for another 79 d, by adding 0.2 mg L-1 of Pb(NO3)2 into an acidic substrate solution. After 180 d, biofilm was matured as the removal efficiencies of COD and Pb(II) were constant at 30 and 60%, respectively. The rate of bioaccumulation was evaluated using the modified Gompertz model. The living microbes can gradually consume Pb(II) and the bioaccumulation efficiency is 14.0 mg Pb g-1 organic matter (OM). The Pb(II) ions act as the trace element, which can enhance the growth of microbes in the biosorbent. The biosorption can be described using Freundlich model. Under the acidic Pb(II) solution (pH 4.0), the highest distribution coefficients of biosorption is 6.3 mg Pb g-1 OM, and the sorbed Pb is biochemically fixed onto OM. The acidic Pb(II) solution can prevent the deposition of Pb(II) prior to biosorption. Pb(II) can be stored in accordance with the microbial cell activities by 56% of total Pb(II) removal. Approximately, 44% of Pb(II) is adhered on OM. At the active zone of biosorbent, the free Pb(II) species in the forms of soluble and exchangeable Pb(II) are well sorbed. The biosorbent could present the high benefit to bound the toxic Pb(II) even the contaminated water is highly acidic (pH = 4.0).