Mapping Thermal Energy Resource Potentials from Wastewater Treatment Plants

Georg Neugebauer,Gernot Stoeglehner,René Kollmann,Florian Kretschmer,Thomas Ertl,Michael Narodoslawsky

doi:10.3390/su71012988

Georg Neugebauer, Gernot Stoeglehner + Show 4 more

Open Access

https://doi.org/10.3390/su71012988

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Abstract

Wastewater heat recovery via heat exchangers and heat pumps constitutes an environmentally friendly, approved and economically competitive, but often underestimated technology. By introducing the spatial dimension in feasibility studies, the results of calculations change considerably. This paper presents a methodology to estimate thermal energy resource potentials of wastewater treatment plants taking spatial contexts into account. In close proximity to settlement areas, wastewater energy can ideally be applied for heating in mixed-function areas, which very likely have a continuous heat demand and allow for an increased amount of full-load hours compared to most single-use areas. For the Austrian case, it is demonstrated that the proposed methodology leads to feasible results and that the suggested technology might reduce up to 17% of the Austrian global warming potential of room heating. The method is transferrable to other countries as the input data and calculation formula are made available. A broad application of wastewater energy with regard to spatial structures and spatial development potentials can lead to (1) increasing energy efficiency by using a maximum of waste heat and (2) a significant reduction of (fossil) energy consumption which results in a considerable reduction of the global warming potential of the heat supply (GWP) if electricity from renewables is used for the operation of heat pumps.

Highlights

As the scientific debate about the energy turn towards energy efficiency and renewable energy systems moves forward, the search for new renewable energy resources and innovative technologies accelerates
This article focuses on energy provision options related to thermal energy recovery from wastewater treatment plant (WWTP) which is reasoned as follows: One major restriction of heat recovery in buildings and sewers concerns the reduction of wastewater temperature
This section describes the estimation of the thermal energy potential from wastewater and the thermal energy potential recovered from digester gas production

Summary

Introduction

As the scientific debate about the energy turn towards energy efficiency and renewable energy systems moves forward, the search for new renewable energy resources and innovative technologies accelerates. Case studies show that technologies for wastewater heat recovery have been successfully implemented in three locations of the wastewater infrastructure [7]: (1) inside buildings [8]; (2) from the sewer [9] and (3) at the wastewater treatment plant (WWTP) [10]. This article focuses on energy provision options related to thermal energy recovery from WWTPs which is reasoned as follows: One major restriction of heat recovery in buildings and sewers concerns the reduction of wastewater temperature. At WWTPs wastewater heat recovery can be placed after the treatment process [10], so that the temperature reduction of the cleaned wastewater might even lead to positive environmental effects concerning the receiving water courses [14]. WWTPs rank among the major power consumers on municipal level as a German study points out a share of about 20% of the communal electricity demand [15]

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