Anaerobic treatability of waste water from pulp and paper industries.
A black liquor evaporator condensate from a Kraft mill and a waste water from production of corrugating medium were anaerobically treated on a laboratory scale. The composition of the waste waters was determined before and after treatment in fixed bed reactors. Toxicity studies by the Microtox-method showed that both waste waters were highly toxic and a slight decrease in toxicity was achieved by anaerobic treatment. Despite the toxicity efficient anaerobic treatment was obtained. Major components of the condensate were methanol, ethanol, acetone, guaiacol, hydrogen sulfide and dimethyl disulfide. Anaerobic treatment reduced the concentration of the major components considerably with one exception. The concentration of hydrogen sulfide was unchanged. Organic overloading of the fixed bed reactor or a temperature drop resulted in an accumulation of acetone, although methanol and ethanol were degraded. Major components of the waste water from the production of corrugating medium were: Klason-lignin, acid-soluble lignin, carbohydrates, extractives and ash. When the fixed bed reactor was operated at a volumetric load of 1.6 kg COD/m(3).d the following reductions were obtained: Klason - lignin (solids fraction 84%; soluble and colloidal fraction 76%), acid-soluble lignin (solids fraction 56%; soluble and colloidal fraction 7%), carbohydrates (100%), extractives (71%), total-S (80%), COD (73%) and BOD(7) (78%). Kinetic studies showed that condensate was more easily degraded anaerobically than corrugating medium waste water.
Norrman
J
J
BioSystem Engineering Pte Ltd, No. 70 Senoko Road, Woodlands East Ind. Est., Singapore 2775.
Narbuvold
R
R
Nyström
L
L