Variation of physical and chemical properties of aerobic composting of paper sludge on a large scale

The technology of aerobic composting of pulp and paper sludge was studied on a large scale.Composting of paper mill sludge and wood shaves was made in forced-aeration static pile system,and the changes of temperature,oxygen,moisture and content of volatile substance during the composting were monitored and analyzed.The duration of the hermophilic phase was found to be long enough to meet the sanitary standard of the non-hazardous treatment of paper sludge when the sludge and wood shaves were mixed at rate of 10∶1(V/V) on a large scale(300 t/d).The consumption rate of oxygen was the highest at the end of temperature incremental stage,and then decreased until the hermophilic phase.The moisture and content of volatile substance decreased during whole process of composting,and gradually tended to be stable eventually.Compared with the results in the initial stage,the moisture and content of volatile substance in the pile decreased 20.2% and 5.9%,respectively,at the end of composting process.