Overall Impacts

Workbook for estimating operational GHG emissions – CAW version 17 - User Guide

Reference: 23/CL/01/36 - (1)
ISBN: 978-1-84057-976-5
Published Date: 01/01/2099

User Guidance for the Carbon Accounting Workbook (CAW) version 17

Air pollutant emissions across wastewater operations

Reference: 23/CL/01/37
ISBN: 978-1-84057-977-2
Published Date: 20/06/2023

The UK government’s 2019 Clean Air Strategy aims to reduce emissions of five of the most damaging air pollutants:  ammonia (NH3), non-methane volatile organic compounds (NMVOCs), nitrogen oxides (NOx), Particulate Matter (PM2.5) and sulphur dioxide (SO2). Wastewater and bioresources treatment have been identified as potential sources of emissions, however, there is little data available to quantify how significant these emissions are. As an initial step towards achieving the Clean Air Strategy, UKWIR commissioned Atkins Ltd to carry out a study to establish the potential sources of the five pollutants and quantify the impact at both a local and national level. This report presents the main findings of this study: quantification of the current emissions associated with wastewater and bioresources treatment; key areas for further investigation; potential mitigation measures and delivery of the first Air Emissions Accounting Workbook.

Biosolids to land - carbon emissions and carbon capture

Reference: 23/CL/01/38
ISBN: 978-1-84057-979-6
Published Date: 07/06/2023

Biosolids recycling to agricultural land is considered the Best Practicable Environmental Option providing a valuable source of nutrients and organic matter.

These nutrients also offset greenhouse gas emissions produced during artificial fertiliser manufacture.

Knowledge of carbon storage and the factors controlling GHG emissions following biosolids recycling to agricultural land is required. Available literature was reviewed to investigate biosolids and to review Emission Factors.

An overview of soil carbon storage was also carried out to: support sustainable use of biosolids: inform water company business plans: review GHG emission factors. An international seminar also allowed intelligence gathering.

Organic material composition of biosolids influence both SOC retention and N2O loss. Soil carbon retention rates appear much lower for biosolids with a high fraction of easily decomposable carbon. Emisssion Factors tended to be low for biosolids with dry matter of >30%, C:N ratio of >12 or <15% of total N as ammonium-N.