Drying and thermal utilisation of 92,000 tonnes of sewage sludge per year
With the new plant for sewage sludge drying from HUBER, RWE is taking a further technological step: Thanks to pre-drying from about 75% to 10-15% moisture, the sewage sludge has a similarly high calorific value as lignite. In future, 92,000 tonnes of sewage sludge will be dried annually at the plant and thermally utilised in the power plant there.
Rainer Köhler (Chief Sales Officer HUBER SE): ”Successfully carry out projects of this magnitude for renowned customers such as RWE”
”In addition to the numerous smaller and medium-sized projects that we realise, it is major orders such as this belt drying plant for the thermal utilisation of sewage sludge by RWE that we are particularly proud of,” says Rainer Köhler (Chief Sales Officer HUBER SE). ”We successfully carry out projects of this magnitude for well-known customers, which of course include RWE – from technical development to construction and delivery to installation. This demonstrates our leading global position in the field of wastewater treatment, drinking water treatment and sewage sludge recycling.”
Commissioning by the end of 2022
After the engineering order had been processed by HUBER's project team, the company had also received the order for the construction of the dryer in July 2020. Despite the current challenging supply situation, the installation of the plant is proceeding according to plan. Following the installation, the plant is scheduled to be commissioned by the end of 2022. RWE is investing a double-digit million amount in the new belt drying plant.
Similar calorific value to that of brown coal
Due to the pre-drying from 75% to 10-15% moisture, sewage sludge has a similarly high calorific value as brown coal. As a result, the operator of the power plant reduces the amount of raw lignite currently used by a ratio of 1:1. ”We are implementing the coal phase-out and are gradually adapting to it in good time by gradually replacing lignite with predominantly biogenic materials,” says Christian Forkel, head of the Refining Division at RWE Power. ”In this way, our plants will continue to be available to recycle sewage sludge, waste wood and other materials in an environmentally friendly way in the interest of our customers – a big step towards sustainability while ensuring disposal security.”
Co-incineration of sewage sludge enables environmentally sound disposal of residual materials
The co-incineration of input materials (e.g. sewage sludge and secondary fuels) enables the environmentally sound disposal of residual materials. When co-incinerated, the material is used with the main fuel, brown coal, to generate process steam, district heat and electricity.
The Knapsacker Hügel power plant, named after the site in Hürth-Knapsack, operates with power-heat cogeneration and thus uses energy from the fuels in a sustainable manner. At the site, RWE Power is taking a consistent approach to CO2 reduction in the generation of process steam. A plant for processing waste wood and other biogenic fuels was already commissioned there. RWE Power has already invested millions in the Knapsacker Hügel site in recent years. In spring 2020, the intermediate sewage sludge storage facility there was enlarged to around 5,300 m² and two new conveyor lines were put into operation. This optimised the capacities for co-incineration and at the same time secured employment.