The investigation of pulp and paper industry wastewater treatment by jet loop membrane bioreactor system

The paper production industry holds significant importance in the trade and economy of many developing and developed countries worldwide. Due to the high water consumption during paper production and the wastewater generated with high levels of suspended solids and low biodegradability, which leads to water pollution, it is considered one of the industries contributing to water pollution. Biological treatment is commonly employed for treating the wastewater from the paper production industry. With the increasing importance of advanced treatment for the recycling of similar wastewaters, the significance of advanced treatment processes such as membrane technology, known for its compact structure and operational flexibility, has been growing. Jet loop membrane bioreactors (JLMBR) can offer high treatment efficiency and low-cost solutions for the biological treatment of wastewater from the paper industry. This study focuses on the investigation of wastewater from the Balıkesir Varaka Paper Factory using the Jet Loop Membrane Bioreactor (JLBMR) system in a laboratory environment. The study revealed that in the ceramic membrane-integrated system, the removal efficiency of COD ranged from 86% to 99% with organic loading rates of 2.8-5.8 kg/m3day in May, and from 75% to 96% with organic loading rates of 1.81-7.30 kg/m3day in November. In the subsequent part of the study, nutrient addition was implemented, resulting in organic loading rates ranging from 2.04 to 11.61 kg COD/m3day, with COD removal efficiencies between 80% and 99%. The average COD concentration was 5280 mg/L, and the detention time varied between 11 and 30 hours, with ϴc values ranging from 1.4 to 50.4 days. An increase in MLSS concentrations was observed after nutrient addition, with values ranging from 2108 to 9140 mg/L depending on the sludge age. Membrane flux values ranged from 110 to 10 L/m2hour, with an average flux value of 15 L/m2hour without long-term backwashing. Approximately 50% flux recovery was achieved after air backwashing of the membranes, which were subjected to chemical cleaning approximately once a month. The achieved treatment efficiency was observed to be highly efficient considering the system's volume of 14 liters.