Evaluation of Dairy Wastewater Treatment Systems Using Carbon Footprint Analysis

Beata Karolinczak,Radosław Żyłka,Wojciech Dąbrowski

doi:10.3390/en14175366

Beata Karolinczak, Radosław Żyłka + Show 1 more

Open Access

https://doi.org/10.3390/en14175366

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Abstract

Modernisation of municipal and industrial wastewater treatment plants (WWTPs) should be carried out, taking into account its impact on global warming, e.g., through carbon footprint (CF) analysis. An important industrial sector in Poland is the dairy industry. In dairy WWTPs, the aerobic sewage sludge stabilisation applied thus far is being replaced by the anaerobic process. This change is positive due to the possibility of energy production, but it is unclear how it affects greenhouse gases (GHG) emissions. The aim of the research was to perform CF analysis for two scenarios of dairy WWTP operation. The analysis was based on the real operating data of the current system (current scenario) and project of its modernisation (alternative scenario). The current scenario consists of mechanical and dissolved air flotation (DAF) treatment, biological treatment in sequence batch reactors (SBRs), aerobic sewage sludge stabilisation and its final farmland usage. The alternative scenario assumes replacing aerobic stabilisation with anaerobic stabilisation and a combined heat and power (CHP) system. The CF calculations were based on empirical models, taking into account different emission input parameters, expressed in CO2 equivalents (CO2e). The total CF of the current scenario was 22 kg CO2e PE−1 year−1, while the alternative was 45 kg CO2e PE−1 year−1. The largest share in the current scenario belongs to emissions from WWTPs and energy use, while in the alternative, there is the addition of emissions from biogas use.

Highlights

As the awareness of the possible effects of human activities on climate change is growing, there is a need to estimate the emissions of greenhouse gases (GHG) from as many sources as possible
This study examined the impact of changing the sewage sludge stabilisation method on the carbon footprint (CF) of dairy WWTPs
The results of the CF analysis were given in tonnes of equivalent CO2 per year (t CO2 equivalents (CO2e) a−1 ), recalculated into kg of equivalent CO2 per person equivalent (PE) per year

Summary

Introduction

As the awareness of the possible effects of human activities on climate change is growing, there is a need to estimate the emissions of greenhouse gases (GHG) from as many sources as possible. Wastewater treatment plants (WWTPs) are highlighted in the Intergovernmental Panel on Climate Changes (IPCC) guidelines as a source that should be considered in the national GHG emission inventories [1], their share in total. Analysis, it is possible to estimate the global warning potential (GWP) in relation to carbon dioxide (CO2 ). The emission of methane (CH4 ) and nitrous oxide (N2 O) is converted into the equivalent of carbon dioxide (CO2e ). The CF analysis can be used to estimate the GHG emissions from WWTPs [4,5]

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