Small-scale wastewater treatment systems: governance, efficiency, resources recovery, environment contamination risks and innovative solutions for processes optimization (ON-SITE)

kaikki logot ON-SITE


Similarities and differences of wastewater treatment regulations in Nordic countries

In general, the Nordic countries share a number of similarities related to environmental protection and sanitation regulations. However, there are substantial differences among the member countries regarding the governance of wastewater treatment systems outside sewage networks. In addition to regulated pollutants (nutrients and organic compounds), effluents of small-scale wastewater treatment plants are also know to contain other contaminants such as pathogens and micropollutants. Wastewater treatment plants (WWTP) and small-scale treatment units are not specifically designed for micropollutant removal.

Challenges in removal of micropollutants

Thus, it is difficult to estimate the micropollutants load entering the environment from wastewater treatment systems. In addition, environmental impacts related to micropollutants in the environment are not yet well understood and are challenging to foresee due to the huge number of substances included in this category and the lack of data regarding occurrence, fate and toxicity needed for a comprehensive assessment.

Removal of micropollutants in conventional WWTP and small-scale systems occurs mainly via biological and/or chemical transformation and sorption. However, removal efficiencies for micropollutants like ibuprofen and diclofenac vary considerably between different treatment systems and mode of use and is often not very effective.

Bioaugmentation could be part of solution?

Bioaugmentation of wastewater treatment systems has been suggested as a feasible technology for enhancing the removal of micropollutants, nitrogen or phosphorous in natural and conventional systems. However, successful application of bioaugmentation techniques in small-scale wastewater treatment systems has not been reported to date. Development of technology and methodologies in this field can lead to cost effective, less energy intensive and sustainable solutions for removal of micropollutants than methods applied in conventional wastewater treatment plants.

Aims of the project

The ON-SITE project commits to examine the governing principles of wastewater treatment systems not connected to sewage network in Finland, Sweden and Norway via literature survey and interaction with relevant authorities, systems producers and suppliers (SME’s). The goal is to create a detailed description and comparison of the procedures and related regulations as well as current practices and strategies applied in the countries. The project aims to create a strong cross-border collaboration among several actors, which is essential for widening the network of involved authorities, municipalities and research institutions, thus improving their ability to share experience, expertise and overcome shared obstacles.

    The project will work towards evaluating and developing innovative cutting-edge bioengineering processes and methodologies (like bioaugmentation) for improving removal of target pollutants (nitrogen and selected micropollutants) in small-scale wastewater treatment systems. The goal is to create a strong link between research, innovation and technological business development. 

    The ON-SITE project will also evaluate possibilities and investigate the feasibility of different options for nutrient recycling in the program area. A comprehensive assessment of well-known and alternative solutions will be carried out based on available data regarding energy requirements, maintenance needs, costs etc. The work will be conducted in close collaboration with stakeholders so that the whole recovery and recycling chain can be assessed.

    Target groups

    Authorities, municipalities, research institutions, decision makers, small wastewater treatment systems´s producers and suppliers (Small and Medium Enterprises, SME’s), farmers


    University of Oulu (research group Water resources and environmental engineering) is the leading partner of the whole ON-SITE project. Other partner is Luleå University of Technology (Department of Civil, Environmental and Natural Resources Engineering).

    More information

    • Ritva Nilivaara, SYKE´s project manager of the project ON-SITE, tel. +358 295 252 052,
    • Project main page (University of Oulu)
    • Project page (Luleå University of Technology)
    Published 2019-04-01 at 14:47, updated 2020-12-01 at 15:20

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