Presently no chemicals are added in the pulp/paper mills wastewater
treatment. There is a loop hole with the Biological Oxygen Demand test
utilized. Regulators depend on the Biological Oxygen Demand test. All
mills are discharging raw untreated wastes high in Chemical Oxygen
Demand, (COD), Total Organic Carbon, (TOC) and COLOR. Liquid Alum
solution is added to raw influent. All electrical energy aerated systems
are eliminated. All flows from sewers join prior to the entrance to
clarifier. The continuous in-line pH controller is proprietary as well as
the continuous in-line COD analyzer. Because mills wastewater is
amphoteric, it is mandatory that the raw influent pH be adjusted to range
of 5.7 to 6.0 for optimum removal efficiencies. Aluminum chloride, ferric
chloride and ferrous sulfate may be replaced for alum with higher
operating costs. The precipitate is thickened, dewatered and incinerated,
and approximately 75% of the chemicals regenerated.