Effluents from the pulp and paper mills contain harmful solids and dissolved matter that must be treated before being released into the environment. The contaminants are made from a combination of waste produced from debarking, pulp washing, bleaching, and regeneration of cooking chemicals. This section encompasses instruments used for measuring various parameters, including biological oxygen demand, incineration of solids, pH, and TDS value. These measurements provide valuable insights into the toxicity present in the effluent.