Sludge reduction levels achievable, and the full-scale capital and operating costs, are site and wastewater dependent. Bioremediation of arsenic contaminated wastewater uses a solid matrix material to support high-density bacterial growth. When the column is saturated, the arsenic is stripped and concentrated by filtration. This system is applicable also to semi-passive remediation of a pond. There are clear benefits using biological processes for removing heavy metals.
Biological processes use economical agricultural-based products for bacterial nutrients.
Biological processes require minimal, or no solution pretreatment. Biological processes produce minimal sludge quantities. The new technology Chemical-biological treatment of wastewater holds the promise of being more economical than either chemical or biological treatment, alone. Chemical treatment at levels where the stoichiometry is effective and economical for treatment, followed by biological treatment as the polishing step. A chemical precipitation followed by biological treatment is also possible in a staged reactor system.