Trends, insights and effects of the Urban Wastewater Treatment Directive (91/271/EEC) implementation in the light of the Polish coastal zone eutrophication

Michał Preisner,Dominika Szołdrowska,Marzena Smol

doi:10.1007/s00267-020-01401-6

Abstract

The intensification of the Baltic Sea eutrophication is associated with the increase of anthropogenic nutrients loads, mainly nitrogen and phosphorus introduced into surface waters from a diffuse, point and natural background sources. Despite the observed decreasing trends in nutrient concentrations in some parts of the Baltic Sea, eutrophication-related indicators continue to deteriorate. This accelerates harmful algal blooms and dissolved oxygen deficits resulting in severe ecosystem disturbance. The paper presents trends, insights and effects of the Urban Wastewater Treatment Directive 91/271/EEC implementation in Poland based on the nutrient riverine loads from Polish territory with particular attention given to the development of municipal wastewater treatment plants under the National Wastewater Treatment Programme 2003–2016. Environmental effects of wastewater infrastructure modernisation are investigated by using available data on the changing nutrient concentrations in the coastal water in 3 basins (Gdansk Basin, Bornholm Basin and Eastern Gotland Basin) belonging to the Polish Exclusive Economic Zone within the Baltic Sea. The results show that the decreasing trend regarding phosphorus loads reduction from municipal effluents was achieved while a stable trend with temporary increases was achieved in terms of nitrogen loads. Moreover, the investigation provides information about the potential bioavailability of discharged effluents before and after the Directive implementation by including total and inorganic forms of nitrogen and phosphorus in the analysis.

Highlights

The Baltic Sea is one of the most severely polluted seas on the globe with eutrophication being its biggest threat resulting in harmful algal blooms (HABs) (Kahru et al 2020) and dissolved oxygen (DO) deficits (Diaz and Rosenberg 2008; Breitburg et al 2018)
The current study presents trends, insights and effects of the Urban Wastewater Treatment Directive 91/271/EEC (UWWTD) implementation in Poland based on the nutrient loads discharged from Polish territory with particular attention given to the development of municipal wastewater treatment plants (MWWTPs) and nutrient loads discharged with municipal effluents to the Baltic Sea
One of the most important tools supporting the abatement of eutrophication in the region is the European Regional Development Fund (ERDF), from which multiple infrastructure investments in wastewater sector were co-financed in the Member States in the Baltic Sea region (Avdiushchenko 2018)

Summary

Introduction

The Baltic Sea is one of the most severely polluted seas on the globe with eutrophication being its biggest threat resulting in harmful algal blooms (HABs) (Kahru et al 2020) and dissolved oxygen (DO) deficits (Diaz and Rosenberg 2008; Breitburg et al 2018). The above issue was discovered in the 70–80s of the 20th century, mainly due to excessive human activity in the Baltic Sea region which still becomes a major challenge (Raudsepp et al 2019). The Helsinki Commission (HELCOM) have developed multiple measures and recommendations for all countries in the Baltic Sea region for efficient eutrophication mitigation. Environmental Management (2021) 67:342–354 to HELCOM data, Poland is the major nutrient polluter of the Baltic Sea with approx. 25% of total nitrogen (TN) and 32% of total phosphorus (TP) load (HELCOM 2018a)

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