What is paper pulp treatment?

The paper industry uses very high volumes of process water for pulp preparation and bleaching among other processes. Water is needed to make paper pulp out of fibers such as cellulose, wood or recovered paper.

What is paper effluent?

The effluent is a complex combination of waste produced during the pulp and paper making process including wastewater from debarking, pulp washing, bleaching and regeneration of cooking chemicals. The effluent is treated prior to release, typically in 2 stages: primary and secondary treatment.

What are dregs in pulp and paper?

Dregs are mainly composed of sodium and calcium carbonates (Na2CO3 and CaCO3) and sodium sulfide (Na2S), and are generated from the separation of CaCO3 and CaO in the green liquor. Grits are formed mainly by CaCO3 and CaO which did not react in the slaker26,27,28,29.

What is paper mill effluent?

2.1. Pulp mill effluent has high chemical and biochemical oxygen demand and some wood derived organic compounds, metal(loid)s, fatty and resin acids, and relatively high C:N ratios (Tables 2 and 3). Kookana and Rogers (1995) reviewed the effect of pulp mill effluents on soil properties.

What is COD in paper industry?

The COD (Chemical Oxygen Demand) of treated effluent represents how effective a treatment technology is in its ability, to remove the total organic material present in the influent. The characteristics of the effluents are dependent on the production process and the raw materials.

What is ratio of BOD and COD in general?

The ratio between BOD to COD is variable with season and geographical location. generally it is 0.4 – 0.45 in summer and increases 0.3 – 0.35 in winter. Depend on the type of your wastewater can vary from 0.6 to 0.8, this rate can be consider biodegradable (biological treatment is recommended).

What is green liquor dregs?

Green liquor dregs are the suspensed solids removed during green liquor clarification, being posteriorly washed with water containing lime sludge to pH control.

What is ETP process?

TREATMENT. EFFLUENT. SLUDGE. • ETP (Effluent Treatment Plant) is a process design for treating the. industrial waste water for its reuse or safe disposal to the environment.

What is the PH of green liquor?

green liquor dregs is currently sitting above 12.5, at this point it is considered hazardous and above the spec of 11.5 for landfilling. We are using a pre-coat filter and dregs centrifuge, the washing does not help with the PH reduction.

Is green liquor harmful?

Green liquor can cause severe skin burns, eye and lung damage. As any caustic liquid, exposure to green liquor can cause coagulative necrosis that can lead to extensive tissue damage, as well as, damage to the respiratory system if mists or vapors are inhaled.