Wastewater (water effluents)

Sustainable pulp and fiber production comes with strict criteria not only for air emissions but also for water effluents and wastewater treatment. National or regional legislation as well as several industry standards and certification schemes – such as EU BAT, EU Ecolabel, and ZDHC – identify priority substances of concern and give guidance for reducing emissions and hence avoiding harmful impacts on water bodies. Lenzing has decades of experience in the safe handling and treatment of process chemicals used during manufacturing, including water-related issues. Lenzing has been leveraging this extensive knowledge to develop and shape today’s industry standards through multi-stakeholder initiatives such as ZDHC. Discharge limits are included in the environmental permits issued for all sites by relevant authorities based on national legislation. Additional intragroup discharge limits that reflect best practices may apply under internal environment standards.

Process water is treated by biological wastewater treatment plants (WWTPs). The Lenzing Group has wastewater treatment plants at all its sites except Grimsby (United Kingdom). However, the wastewater situation at Grimsby complies with all local laws and regulations as well as the EU Water Framework Directive. Planning has begun for the construction of a wastewater treatment plant at the Grimsby site in cooperation with local government with a view to applying new technology from an ongoing R&D project.

Lenzing’s site in Purwakarta (Indonesia) is making good progress in improving its wastewater after a project was launched in 2018. The project aims to debottleneck the capacity of one of the two existing wastewater treatment plants by 2022. The sewage collection and treatment system is emarked to be upgraded in order to comply with future requirements. The project also involves building a utility water treatment system and improving the existing stormwater drainage systems. Dedicated teams are currently working on basic engineering for the project, which is expected to be implemented by the target deadline in 2022.

In 2021, another WWTP upgrade project was approved for the site of Mobile (USA). The lyocell plant was one of the first of its kind and will undergo a modernization of the existing WWTP in order to meet the Group’s sustainability strategy and target on COD emissions. This investment will not only help fulfilling future ZDHC requirements for lyocell production but also allow potential enlargement of fiber production capacity. The project includes refurbishment of existing structures and new modular elements for a most up-to-date waste water treatment. The investment thereby ensures an extended life cycle of the WWTP. After the project was successfully approved, construction work was initiated in late 2021 and commissioning is expected by end of 2023.

Organic chemicals from waste streams from the pulp production process are extracted early on in the biorefinery process at the Lenzing site (Austria), which significantly reduces the chemical oxygen demand (COD) of effluent water. This is one example of best practices where potential waste streams are converted into useful products, thereby avoiding pollution and reducing the amount of waste to be treated at the wastewater treatment plant.

To improve the wastewater management in China, Lenzing took control of the wastewater treatment plant in November 2019. Since then, the management of Lenzing’s site in Nanjing has become responsible for the operation of the wastewater treatment plant and its further optimization. Thanks to ongoing improvements and data monitoring, the wastewater treatment plant complies with Lenzing’s Group Environmental Standard and the emissions discharged are reported in the group environmental data.

The Group Environmental Standard is designed to reflect the benchmarks and emission thresholds of the best available technologies for pulp and fiber production. The ambitious framework of the standard aims for continuous improvement. That said, some requirements have not been met by particular sites. However, no infringements of regulatory discharge limits occurred during the reporting year.

Sulfate emissions mainly originate from the viscose process; COD emissions originate from pulp and all fiber production processes. Their reduction is part of the Lenzing Group’s sustainability targets. Total emissions of COD, sulfates, and amines increased in 2021 over 2020 due to several trial runs for expansion of specialty fiber products, especially in China and Indonesia. However, as the amount of marketable fiber products were again on pre-pandemic levels, specific emissions obviously decreased compared to the previous year (table "Absolute emissions to water after wastewater treatment plant" and "Specific emissions to water after wastewater treatment plant").