Towards improved management of industrial sewage

BEST Project was finalized after three productive years. In cooperation with project partners in Finland, Estonia, Latvia, Poland and Russia project BEST – Better Efficiency for Industrial Sewage Treatment has assessed the current management of industrial wastewaters, pinpointed bottlenecks as well as tested and collected recommendable practices and solutions to improve the situation. The main outcome is the new Baltic Sea Region wide and national level guidelines for management of industrial wastewaters handled in municipal networks.

During recent years, the treatment efficiency of municipal wastewater treatment plants (MWWTPs) has been improved significantly in countries bordering the Baltic Sea. However, as MWWTPs are primarily designed to treat wastewater from homes, the treatment processes can easily be disrupted if plants have to cope with industrial wastewater of abnormal quality or quantity.

Insufficient permitting in large industries

One of the most alarming results of the project was that in some cases environmental permitting of industrial companies is deficient and not regulating discharged effluents in accordance with relevant EU directives, leaving MWWTPs powerless in the situation. The two main existing mechanisms for controlling industrial wastewater discharges into MWWTPs include environmental permits for industrial operators and contracts between the industrial operator and the MWWTP.

Inadequate environmental permits prevent issuing of sufficient requirements for industries to pre-treat and monitor the discharged sewage, impair and weaken the treatment and functioning of WWTPs and ultimately lead to nutrient and hazardous substance emissions to local watercourses and the Baltic Sea. Furthermore, in several BSR countries like in Estonia, Latvia, Lithuania, Poland and Russia the priority and hazardous substances are mainly not listed in integrated environmental permits nor industrial wastewater contracts, and therefore, these are not monitored by the industries nor supervised by the environmental authority.

The control and monitoring of priority and hazardous substances in industrial wastewater must be improved on all levels, meaning that environmental authorities, water utilities and industrial organisations should be aware of potential discharges to and impact on municipal systems. The new guidelines and the policy brief compiled within project BEST highlight action points to be taken by both environmental authorities, industries and wastewater treatment plants to improve the situation.

In the project, the assessment of the current situation concerning industrial wastewater management gave an overview of the situation in the Baltic Sea Region. In several countries waste collection, treatment and disposal, chemical and fabricated metal products, beverage, meat and dairy industries were assessed to cause specific concern for sewage management at MWWTPs. If not properly pre-treated and supervised, industrial sewage from e.g. fabricated metal industries may contain harmful or toxic substances, which are not removable by municipal treatment processes. Also otherwise harmless effluents from food processing facilities may disrupt and block municipal wastewater treatment plant processes if large amounts of materials, such as dairy products, are suddenly released into sewage systems without prior notice.

Local cooperation is key

Agreeing on cooperation practices among the MWWTP, industry and environmental authority was found in the project as one of the most important measures to minimize the damages caused by unexpected situations and to help the wastewater treatment plant to prepare for accidental sewage discharges from industries. Training of staff, site visits and biannual meetings at both the MWWTP and in the industry enable mutual understanding of each other’s processes and adequate actions in differing situations. To support increasing cooperation and capacity development in everyday work for all parties, training materials and best practices examples were collected in an easily understandable format within the project.

Cooperation and local management solutions were also tested in practice. The project supported two dairy companies in Estonia and Latvia to improve their pre-treatment processes. Efficient pre-treatment of dairy sewage was crucial for the local MWWTPs to reach sufficient treatment. Moreover, in Poland project BEST invested in an entirely new treatment line for industrial sewage at a small MWWTP. Here, a modern method for phosphorus filtration with calcium silicate enables full phosphorus recovery for further use e.g. in agriculture. Another Polish MWWTP invested in a pilot system to test prospects of biogas production by co-fermentation of wastewater sludge and biodegradable industrial waste. In Estonia, a MWWTP purchased a portable monitoring equipment in order to track the industries responsible for occasional high discharges of harmful substances to the MWWTP. Such devices would be very helpful also in wider use in MWWTPs around the Baltic Sea.

Miitta Rantakari
City of Helsinki