The problem with wastewater – and how we can solve it
Globally, 80% of wastewater is released into the environment without adequate treatment (UN WWDR, 2017). This gap in wastewater treatment results in the pollution of soil, surface water, and groundwater, which have a detrimental effect on our ecosystems, human health, and economic activities. With such a large gap to fill, is there hope on the horizon for a better future? At Langhus Norway, Scandi Energy think they may have found a solution.
A multi-dimensional problem
In fact, urban wastewater and agricultural production are the two most significant sources of nitrogen and phosphorus emissions to freshwater. As the freshwater environments become progressively enriched with these minerals and nutrients – a process known as eutrophication – algal blooms occur. This rapid increase in the population of algae in the freshwater environment eventually leads to an unstable ecosystem for fish and other aquatic life forms and a tainted water supply.
Additionally, sanitation and water-related diseases are common especially in areas with a high reliance on contaminated surface water for drinking water and recreational use.
With regards to the economic aspect, poor water quality hampers economic development and directly affects industrial production, fisheries, aquaculture, and tourism. Inadequate water quality may also directly hinder the export of goods due to restrictions on contaminated products.
Increased rates of nutrient recovery from aquatic environments are therefore necessary to reduce these harmful effects on health, environment, and society.
Wastewater pollution in Norway
Nutrient recovery is especially important in high-risk areas such as the Norwegian fjords. In 2019, wastewater handling in Norway accounted for 12.4% of total emissions in the waste sector with 1.1 million tonnes of CO2 equivalents (NEA, 2021). Annual discharges of phosphorus and nitrogen from wastewater treatment facilities in 2020 were 1,023 tonnes and 16,480 tonnes respectively (Statistics Norway, 2021). Excess nitrogen and phosphorus discharged from these facilities could be used in alternative ways to remove inefficiencies in the nutrient cycle.
“The full recovery of nitrogen, phosphorus and potassium from wastewater
can offset 13.4% of the global demand for these nutrients in agriculture,
but current technologies of nutrient recovery from wastewater have yet to reach 100%
efficiency levels” (Fernández-Arévalo et al., 2017; Ward et al., 2018)
In the Oslofjord, the issues of wastewater pollution have historically been particularly severe. The second half of the 19th century was characterized by rapid industrialization and population growth in Oslo which directly led to an increase in the amount of wastewater generated and discharged into the inner Oslofjord. Deteriorating conditions due to increased discharges of organic materials, nutrients, and heavy metals led to a significant degradation in marine environments.
In the 1960s, the Norwegian Institute of Water Research (NIVA) released a report which detailed the interactions between wastewater discharges, fjord processes, and fjord health and were able to find an unequivocal connection between wastewater discharge and increased eutrophication in the fjords. Regulations were therefore implemented in the 1970s to ensure that wastewater received adequate treatment. The establishment of the VEAS treatment plant - Norway’s largest wastewater treatment facility, was a direct response to combat poor surface water quality in the Oslofjord. VEAS uses mechanical, biological, and chemical treatment protocols for wastewater to ensure the highest level of treatment before discharge. However, treatment efficiencies are still an area of concern due to infiltration from ground water and storm water resulting in fluctuations in the quality of wastewater discharged.
Closing the gap
As the world continues to develop, we as a collective find ourselves looking to fill the gap in sustainable water supply by looking for more ways to supply and treat our water – while reducing our footprint. This has led to a heightened focus on the potential for wastewater management solutions to close this gap. Current wastewater treatment solutions have evolved to be more energy efficient whilst achieving higher recovery rates. However, many wastewater treatment plants are struggling to meet legislative requirements for wastewater treatment (nitrogen and phosphorus emissions) and re-use. Nevertheless, technological advancements remain our best hope for offsetting the negative effects of a progressive increase in freshwater consumption.
Current technologies on the market solve the existing problem of insufficient reductions in nitrogen and phosphorus levels in wastewater by introducing another problem. Traditional iron-based and aluminum-based compounds are effective in reducing nutrient loads in wastewater but create other problems that must be addressed with additional products such as polymers. Polymers are primarily used in the consolidation and drying of sludge to reduce transportation and high energy costs associated with sludge disposal. However, polymer use incurs higher costs for treatment facilities, and have also been shown to have negative health impacts and environmental hazards associated with their use.
Enter Scandi Energy
At Langhus outside Oslo in Norway, Scandi Energy is a Norwegian green-tech company working to solve these problems. The company was established in 2016 and has since been working on solutions that solve existing problems with waste and wastewater treatment. The fuzzy yet noble goal is a total end of waste.
These days, the company is working to introduce the Dwater Unit to the Nordic aquaculture and municipal wastewater treatment market. The Dwater Unit is a combined drum filter, dryer, and hygienizer in one compact system that has demonstrated disruptive wastewater treatment performance.
Lately, the technology has been deployed over a 3-year period in the EU Horizon 2020-funded GAIN program (Green Aquaculture Intensification Program) at Salten Havbrukspark. The program focuses on highlighting technologies that support the successful eco-intensification of aquaculture. The Dwater Unit yielded strong results during the program, demonstrating removal of up to 99% of phosphorus, 99% of BOD, and 94% of nitrogen from reject water of a smolt facility.
Removing and recycling nutrients is important in itself. However, the Dwater Unit takes it one step further; with up to 90%+ dry matter, the output sludge in which the nutrients are retained has the potential to be mixed and used as an organic fertilizer product. In stark contrast to sludge today – which is typically disposed of as biogas or incineration feedstock – recycling in this manner enables a truly circular local loop with a direct valorization pathway for sludge.
Furthermore, the prototype operated at Salten utilized no polymers or other chemicals to achieve these results, and only approx. 0.3 kWh (!) per cubic meter wastewater treated - far below prevalent industry benchmarks. The extraordinary feats are achieved using a proprietary and mission-specific semi-conductor technology.
With the Dwater Unit up their sleeve, Scandi Energy believe it possesses the key to disrupt the ways we think about wastewater treatment. As the product enters the market in 2022, we may soon see new glimpses of hope for tackling modern wastewater treatment challenges and unlocking inefficiencies throughout the water management cycle.
© April, 2022