How to sequester the CO2 emitted from large scale municipal wastewater treatment plants ?

Most of the municipal treatment plants employ aerobic treatment as a part of the secondary treatment process. All the organic impurities which gets oxidized forms CO2 as a product which is emitted to the atmosphere. Even if the CO2 generated might not be in such significant levels as compared to other sources of carbon pollution, why create another problem while we are offering a solution for another ? Are there any simple feasible alternative to this ?