Transforming wastewater from agro-based paper production into sustainable revenue

Producing Kraft paper, particularly with a focus on recycled and agro-based inputs, presents significant sustainability challenges, especially concerning water loop recycling. In water-intensive processes like papermaking, limited freshwater usage creates a semi-closed-loop system, where water is reused multiple times. Over time, this leads to the accumulation of organic, inorganic, and recalcitrant pollutants, which are resistant to biodegradation. These contaminants contribute to rising Total Dissolved Solids (TDS) levels, discoloration, and unpleasant odors in the water, which can pose environmental and health risks if not adequately treated.

Additionally, insufficient wastewater treatment facilities often struggle to manage the large volumes of process water, resulting in partial discharges that may fail to meet environmental standards set by regulatory bodies like the Pollution Control Board (PCB). Odor management becomes a particularly pressing issue in such scenarios, as volatile compounds from untreated wastewater can impact nearby communities. Addressing these challenges requires innovative and efficient treatment solutions that ensure compliance while supporting sustainability goals.

Sainsons Papers primarily uses recycled fibers along with wheat and rice straws as raw materials, minimizing freshwater usage in their production process. However, this limited water input led to a concentrated water loop with high levels of organic, inorganic, and recalcitrant pollutants, resulting in elevated Total Dissolved Solids (TDS) and a strong, unpleasant odor that posed health risks to surrounding areas. Compounding the challenge, the facility lacked adequate wastewater treatment capacity to process the entire volume of water generated, leading to partial discharge that failed to meet Pollution Control Board (PCB) regulations.

To address the challenges of wastewater treatment and compliance, Sainsons Papers opted for the implementation of the BIOPAQ® ICX reactor, complemented by engineering upgrades to their existing aerobic system. The BIOPAQ® ICX is a state-of-the-art anaerobic treatment solution designed to efficiently handle high concentrations of organic pollutants, making it ideal for the complex wastewater produced in Kraft paper manufacturing. Paques commissioned an 8.5 x 18.3-meter ICX reactor with a treatment capacity of up to 18,000 kg COD (Chemical Oxygen Demand) per day and a hydraulic capacity of 4,500 m³/day. The system not only mitigates the buildup of pollutants but also converts them into biogas, which can be utilized as a renewable energy source, effectively addressing both the environmental and operational challenges faced by the paper mill.

The organic load to the aerobic post treatment system was reduced by a factor 3 due to implementation of the BIOPAQ^® ICX reactor. This has resulted in a stable final treatment process that meets the discharge standards. On top of this, the treatment costs per cubic meter water treated have nearly halved due to the reduced energy consumption of the aerobic plant. As such, implementing the BIOPAQ^®ICX reactor creates a profitable business case in itself.

With Paques technology, Sainsons Papers achieved the production of odor-free Kraft paper while transforming wastewater treatment into a sustainable and profitable process. The biogas generated through the BIOPAQ® ICX reactor is upgraded into Compressed Biogas (CBG), which is supplied to nearby fuel stations under the SATAT (Sustainable Alternative Towards Affordable Transportation) initiative.

Additionally, the reactor produces valuable granular biomass, which the company resells as a revenue-generating resource. The biogas can also be utilized in the mill's boiler unit, significantly reducing energy costs. By implementing this solution, Sainsons Papers not only enhanced operational efficiency but also achieved full compliance with Pollution Control Board (PCB) regulations.