Waste and wastewater : Tomorrow’s green energy

Waste and wastewater now represent a resource that can be recovered as energy in the form of heat, electricity or fu

Keeping track of waste

Turning waste into green energy has many advantages. First of all, it makes it possible to side-step the constraints linked to its storage, at a time when regulations in this area are becoming increasingly stringent, especially in Europe and the United States. “The energy transition is a global issue, championed as a priority by countries already highly advanced in the field of resource management optimization,” explains Étienne Petit, Veolia’s CEO in Germany. “As landfill sites have been prohibited since 2005, Germany began considering the recovery of waste and its use as an energy resource at a very early stage,” he states. Most European countries have taken this stance, encouraged by 2008’s framework directive. “Waste-to-energy has become an obvious approach. The United Kingdom has put in place financial incentives to encourage local authorities to recover their waste,” adds Pierre Mauguin, Energy Recovery Business Unit Coordinator in Veolia’s Technical and Performance division.

Going with the flow

Sewage sludge from wastewater t reatment can a l s o be transformed into energy. “Until now, sewage sludge was used for spreading. This is going to be prohibited,” states Étienne Petit. Today, this sludge can be treated to produce RDF (Refuse-Derived Fuel), a high calorific value fuel. “It is an important energy source in Germany for cement works and power plants,” highlights Étienne Petit. Some seven million metric tons of RDF are used in the country each year. Another example in Hong Kong, where Veolia runs the largest sludge treatment facility in the world, T-Park: sludge incineration produces up to 14 MWh of electricity per year. This exceeds the plant’s energy needs, hence the decision to plow back the surplus into the public electricity network. Other avenues are emerging, as Étienne Petit describes: “An iron and steel plant emits a lot of heat. The idea is to capture this so-called ‘waste’ heat, treat it and use the energy potential released to power a city.” It’s a winwin situation: the local authority reduces its CO₂ emissions and the industry monetizes a resource that would otherwise be wasted.

Multiple solutions

“Waste-to-energy solutions take many forms, ranging from incineration with energy recovery in the form of steam or electricity, through the recovery of the biogas produced in waste storage facilities, to the anaerobic digestion of organic waste and sewage sludge,” explains Veolia’s CEO in Germany. At Woodlawn in Australia, Veolia transforms organic waste from the metropolis of Sydney into fertilizer and biogas. This green energy supplies electricity to almost 3,600 households.

Around the world

With a model dominated by nuclear power and inexpensive energy costs, France is not particularly ahead when it comes to the waste-to-energy sector. However, 2015’s energy transition act should speed things up considerably. Greenhouse gas emissions must see a fourfold reduction by 2050, and nuclear’s share in electricity production must be reduced to 50% by 2025. At the same time, 2015’s act looks to halve the tonnage of household waste buried by 2025, i.e. the equivalent of ten million metric tons must no longer be sent to landfill but used in new waste-to-energy channels. This should encourage France to be creative. Veolia, which already enjoys a prime position on the waste-to-energy market, is continuing to rack up successes. This year, Metropolitan Lille chose the Group and its partner Idex to recover its household waste in Halluin’s waste-to-energy plant (WTEP). This makes it possible to supply two district heating networks in Roubaix and Lille, creating a real “heat highway” between the three points. Veolia offers a host of innovations ••• to support the energy transition in France. For instance, the Group has developed Energido, a solution that consists in diverting part of the city’s wastewater to a heat exchanger, which transfers the energy that it contains into a second heat transfer fluid. The calories recovered are transported to a reversible heat pump, which can restore the energy to power a heating or cooling network. Energido is already used to heat the Cercle des nageurs de Marseille pools (see interview of Paul Leccia) and Aix-les-Bains and Arras aquatic centers.

The worldwide potential is vast. The major emerging economies of Asia and Latin America are seeing a sharp increase in their energy needs. “Rather than increasing the number of open landfills on the outskirts of cities, waste recovery offers bright prospects,” summarizes Pierre Mauguin. The proof: Mexico, where ten million inhabitants produce 13,000 metric tons of waste on a daily basis. Today, two thirds of this waste is sent to a storage facility. Veolia has just won a contract for the construction and thirty-year management of one of the largest waste-to-energy plants in the world and the first in Latin America. The plant will process 1.6 million metric tons of household waste each year, i.e. twice as much as the largest French facility, and will produce 965 GWh electricity that will directly power Mexico’s metro.

On behalf of industrials

A strong trend is emerging and Veolia is gradually strengthening its offering for industrial clients in order to help them lower their carbon footprint. “Recovering their waste or wastewater represents a promising solution,” says Étienne Petit. In Germany, for instance, the Group is working with the paper industry in particular. In North Rhine-Westphalia, it helped the paper manufacturer Heinrich A. Schoeller Söhne GmbH & Co. KG optimize its water consumption – the sector is extremely waterintensive – and produce energy from its wastewater.

In the United Kingdom, it took the same approach with the agri-food giant Heinz to generate the steam required to operate the packaging production lines at Kitt Green, the group’s largest facility in Europe.
“We are going to capitalize on the Group’s models to develop an even more structured and powerful industrial offering,” confirms Étienne Petit, adding, “We see the prospect of city-industry partnerships developing within the framework of decentralized local loops. It’s extremely promising from an economic, environmental and social point of view, with the guaranteed creation of strong labor pools. This is an authentic example of a circular economy model in which Veolia comes into its own as a facilitator and integrator thanks to its knowledge of the local markets.”

 

More :
> Recovery of bio-waste and waste
> Producing green energy from the incineration of household waste
> Biogas: producing renewable energy from landfill