Daily activities such as household, restaurants, markets and others especially in Pekanbaru city
will produce waste. Waste produced is both organic and inorganic. A biogas utilization study has been
conducted at the Muara Fajar landfill and 888.6 kW potential electricity has been obtained. Each landfill
will produce leachate containing metals such as iron (Fe), lead (Pb), copper (Cu) and others. The level of
metal toxicity will increasingly pollute the environment. Using the PHREEQC Interactive version
3.0.6.7757 modeling of these contaminants, it can be predicted the transport of the elements and at the same
time reduce the risk of soil and water pollution. Modeling with parameter condition of the presence of
dolomite show that concentration of Ca, Mg and Na metal decreased, while Cu metal showed a significant
increase in the 10th to 50th years and stable at Cu concentration 1.4 mg/L. Lead (Pb) also increased from
the 20th to 60th year and stable at Pb concentration 0.25 mg/L. In conditions without dolomite,
concentration of iron (Fe) increase in the 15th year namely 0.175 mg/L and constant for the following year
while Ca, Na and K have decreased to reach zero concentration.