2018-1-2

As the population of the world increases, and economies continue to develop, energy, water, materials of different types, and nutrients for food production will be needed in ever-increasing amounts. The water-energy nexus is well-understood in research circles, but one could modify this paradigm to water-nutrients/materials-energy nexus in order to incorporate recovery of substances that can be recirculated to the anthroposphere. ‘Resources’ would thus include both energy and materials (elements, compounds and mixtures – both organic and inorganic). Research in, and implementation of, recovery of different types of resources – material and energy – from wastewater (municipal, agricultural and industrial) has been going on for quite some time now. It will not be wrong to say that the imperativeness and importance of research in this field has been earnestly appreciated by academia, industry, utilities and governments alike in many parts of the world, over the last decade. This paper is a literature review of selected publications from the period 2010–2018, from a wide range of journals, focusing on resource recovery from wastewater. The selected publications originate from 44 different countries (in six continents) of the world.

The article presents the initiative behind the Bolmen Research Station in Hylte Municipality, South Sweden, which was initiated in 2017, enabling site-based research, development and innovation on lakes and lake-based activities starting at Lake Bolmen. This lake is the main raw water resource for Skåne. Since 1987, the company Sydvatten has taken raw water from the lake to the drinking water treatment plant Ringsjöverket in Stehag, Skåne. The research station has been established to increase knowledge about the lake and how water quality changes over time. However, the station has also been established to link to other relevant topics such as fishing, fish conservation, outdoor life, tourism, local business development, regional and community development, and green rural services.

In this work, a multi-criteria analysis (MCA) method has been developed for evaluation and comparison of alternative drinking water strategies. A selection process of options was proposed and three options for weighting purpose were compared. The work includes an introductory literature study for identification of criteria and indicators (K o I) used during assessment of sustainable water and sanitation systems. Through four workshops, a panel group presented alternatives, as well as general K o I, selection and ranking of 10 K o I and finally adding weight parameters. The production process of options performed by brainstorming, mapping and the workshop showed to be a time-efficient method that generated active discussions. The method chosen is effective for comparison of alternative strategies and the different methods of weighting showed no importance for the case study finding.

Soil-based wastewater treatment, i.e. septic tanks followed by an infiltration or a sandfilter bed is the most common solution for small scale wastewater treatment in Sweden. In this project four students have surveyed 217 households in a field study. Grab samples have been taken on both suspended solids from the septic tank and on the effluent from sandfilter beds. Visual inspection camera was used to determine the status in the infiltration pipe. The analysis of the biological performance shows that soil-based systems are robust and fulfill the limit for reduction of organic matter set by the Swedish authorities. One out of 10 systems in the study did not perform according to expected levels due to mistakes during design and construction. It is not possible to disqualify a system based on the status in the ventilation pipe. Instead the entire infiltration pipe should be inspected by camera in order to gather enough information. It cannot be concluded that suspended solids are passing through the septic tanks on such levels that the process in the following steps are disturbed. The technique with using a visual inspection camera yields plenty of useful information.