Suitability Pre-Assessment of in-Sewer Heat Recovery Sites Combining Energy and Wastewater Perspectives

Franz Huber,Thomas Ertl,Florian Kretschmer,Georg Neugebauer

doi:10.3390/en13246680

Franz Huber, Thomas Ertl + Show 2 more

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https://doi.org/10.3390/en13246680

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Abstract

In many countries around the world heating (and cooling) has been and will remain the biggest energy sector, but it is still widely dominated by fossil energy sources today. Wastewater as a source of renewable energy contains large amounts of heat and due to its place-bound localization in urban sewer systems it is usually also situated in very close distance to potential heat consumers. However, one has to keep in mind that heat extraction from wastewater might have undesired impacts on temperature-sensitive treatment processes in the related wastewater treatment plant (WWTP). To assess the potential impact of in-sewer heat recovery on inflow temperature, two different approaches are available today: a simple (but less significant) alligation alternate, or very accurate (but less practical) mathematical models. To close the gap between practicability and significance this article introduces a novel approach to pre-assess the suitability of in-sewer heat recovery sites based on little and easily available data considering energy- and wastewater-related perspectives. A case study application demonstrates the informative value and general usability of the approach. Consequently, the proposed procedure can provide guidance and a template for related investigations at any place in a conventional (combined or separated) sewer system.

Highlights

Climate change is one of the great challenges of our times
The review of the three mentioned documents resulted in the deduction of eight different thematic categories determined to be relevant for in-sewer heat recovery and suitability assessment
To describe the “energy-related potential” at an in-sewer heat recovery site, the following four categories were determined to be of relevance:

Summary

Introduction

Demand “access to affordable, reliable, sustainable and modern energy for all” and “urgent action to combat climate change and its impacts” as formulated in their goals for sustainable development. In this regard the climate and energy framework of the European Union [2] defines (i) a cut in greenhouse gas emissions, (ii) an increase in the share of renewable energy and (iii) an improvement in energy efficiency as key targets.

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Conclusion