Circular Economy in Wastewater Management—The Potential of Source-Separating Sanitation in Rural and Peri-Urban Areas of Northern Finland and Sweden

Abstract

Current practices in wastewater management lead to inefficient recovery and reuse of nutrients and can result in environmental problems. Source separation systems have been shown to be an efficient way of recovering nutrients and energy from wastewaters, both in rural and urban context. Studies on nutrient recovery potential and life cycle impacts of source separation systems are mainly limited to small systems (for example a few households) while the impacts of upscaling source separation to a regional level have hardly been studied, especially in sparsely populated areas where the cost of the connection to a main treatment plant is higher. This study examines the regional nutrient balance of two source separation scenarios—black water separation and urine diversion—and compares them to the existing conventional wastewater system. The analysis comprises three sparsely populated regions of northern Finland and Sweden, including rural, peri-urban and urban areas. In addition, climate impacts are assessed based on existing life cycle assessment (LCA) studies. According to the results, by source separation it is possible to achieve a significant increase in the recovery rate of phosphorus (41–81%) and nitrogen (689–864%) compared to the conventional system. Depending on the region up to 65% of the mineral phosphorus and 60% of mineral nitrogen fertilisers could be theoretically replaced. Furthermore, the climate and eutrophication impacts would decrease with the implementation of such systems, but an increase in acidification may occur. However, even if the benefits of source separation systems are undisputed in terms of nutrient recovery, the implementation of such systems would to a large extent require an entire system change of the wastewater treatment sector and a wide paradigm change towards a circular economy.

Dairy Wastewater as a Potential Feedstock for Valuable Production with Concurrent Wastewater Treatment through Microbial Electrochemical Technologies

“…The notion of circularity, which was instigated by industrialized ecosystems, targets the diminishment of resource depletion and discharges/emissions into the environment by completing the circuit of constituents [160]. On the downside of these criteria, material loss needs to be mitigated and can be regenerated either for recycling or reusing.…”

Membrane Technologies for Nitrogen Recovery from Waste Streams: Scientometrics and Technical Analysis

“…For instance, greywater contains higher heavy metals compared to urine and blackwater [ 54 ]. Similarly, blackwater contains the highest pathogen share in wastewater [ 55 ], while most pharmaceuticals and hormones found in wastewater come from urine [ 56 ]. Northern Europe has been one of the most advocating regions for source separation of wastewater [ 57 ].…”

“…Despite the extensive efforts for the implementation of source separation represented by pilot trial projects in countries such as Sweden and Switzerland, the real applications of source separation are still confined to small rural areas outside the service coverage of existing wastewater jurisdictions [ 59 ]. Although blackwater and urine are small streams in volume, they are still important for sparsely populated countries, such as Finland and Sweden, and tourist areas [ 55 , 59 , 60 ]. It is noteworthy that due to the high carbon content in blackwater, it is more favorable to energy production (anaerobic methane generation) than direct nitrogen recovery.…”

Circular Economy Approach for Treatment of Water-Containing Diclofenac Using Recyclable Magnetic Fe3o4 Nanoparticles: A Case Study of Real Water Sample from Lake Victoria

“…Recently, researchers have advocated for the incorporation circular economy in water and wastewater sector with more emphases on water reuse, nutrients recovery, energy recovery, metals and precious metals recovery and other valuable materials [12][13][14][15][16]. In line with the above emphases, some water sectors in countries like Finland [17], Sweeden [17], and Australian [18] have been practicing circular economy. However, there was no emphases by the above researchers on the need for a rethink on the development of new technology and materials that are recyclable in nature to be applied in water and wastewater treatment.…”