Expert: Wastewater treatment gearing up for new investment wave

Sedimentation tank at a wastewater treatment plant.

Increasingly strict environmental regulations and new technologies for removing pollutants and for handling sludge require that Swedish municipalities keep investing in their wastewater facilities. “Investments come in waves. A new wave to come in the next five or ten years will prompt a much greater demand for innovation and financing”, says Anders Finnson, ‎Environmental Advisor at the Swedish Water & Wastewater Association.

Sweden’s municipal wastewater treatment facilities service 8.5 million people living in urban areas. The 1.5 million living in the countryside provide their own on-site treatment. Some 85% of wastewater treatment is concentrated in plants with capacities larger than 10,000 PE (population equivalent). Refitted some ten to twenty years ago, most of these wastewater treatment plants are equipped with modern technologies for removing phosphorus and nitrogen. The Swedish plants remove on average 95% of phosphorus from the water being treated and 62% of nitrogen.

“The wastewater treatment plants with nitrogen removal in Sweden are in a good condition”, says Anders Finnson.

“This development has happened in the past 20 years, as the requirements in the environment protection area became increasingly stringent both in the EU and at the national level.”

The new requirements for phosphorus removal are expected to decrease its concentration in treated wastewater from the current average of 0.3 mg of phosphorus per litre of water to 0.2 mg for the biggest wastewater treatment plants discharging to the Baltic Sea, and from 0.5 mg to 0.3 mg for smaller facilities. This is more ambitious than the recommendations by the Baltic Marine Environment Protection Commission HELCOM, but in line with the Baltic Sea Action Plan and the EU water framework directive.

“The Swedish level of phosphorus removal has been the world’s best so far. But eutrophication is still the largest problem of the Baltic Sea, and external and internal load of phosphorus is a great contributor to aggravating it”, Mr Finnson continues.

“There has been high demand for improvements in treating wastewater from industry, as well as from single-family dwellings and reduce the leakage of phosphorus from agriculture.”

The disposal of sludge is also a major target for investments. The latest statistics available on this sector show that, in 2014, Swedish wastewater treatment produced 200,500 tonnes (dry matter) of sludge. With more wastewater being treated, the amount of sludge is growing, while the demand for it is shrinking.

“As environmental requirements limit the use of almost 75% of sludge in farming, and the need for sludge at landfills and in landscaping will come to an end very soon, in about five years, we’ll see up to 30–50% of the current sludge market disappear”, Mr Finnson says.

“It will leave more sludge, for instance, for incineration, requiring new solutions with future phosphorus recycling from the sludge ash. And it is not unlikely that Sweden, inspired by regulations proposed in other EU countries, will adopt regulations that will require it in the next five to ten years.”

Recently, the Swedish Water and Wastewater Association carried out a survey among the three biggest cities in southern Sweden, the most populated areas of the country, to find out how much they are considering investing in wastewater sludge management.

“This survey showed roughly that investments in sludge incineration alone might reach as much as SEK 5 billion in the coming decade. This figure could be even higher if municipalities in less populated regions consider building their own sludge incinerators. Dealing with sludge in a sustainable way is an important subject in the public debate now, a year before the next general and municipal elections in Sweden”, Mr Finnson continues.

Removing pharmaceuticals in the municipal wastewater is another big challenge and could be an important driver for investments. The first Swedish wastewater treatment facility has now installed a technology for this purpose. This particularly concerns bigger plants with a capacity from 100,000 PE upwards, because this technology is costly and difficult to install and operate.

“Investments in environmental improvements, including wastewater treatment, come in waves. We saw a massive one in the 1950s–70s, when municipalities were first obliged to deal with wastewater treatment and built the facilities we still see today. In the 1990s, requirements for nitrogen removal called for new investments. A new wave is on its way in five to ten years’ time. This will prompt a much greater demand for innovation and financing”, says Mr Finnson.