Carbon reduction and resource recycling from on-farm dairy waste in Australia

PhD by Publication


Grell, Torben. 2023. Carbon reduction and resource recycling from on-farm dairy waste in Australia. PhD by Publication Doctor of Philosophy. University of Southern Queensland. https://doi.org/10.26192/z6723
Title

Carbon reduction and resource recycling from on-farm dairy waste in Australia

TypePhD by Publication
AuthorsGrell, Torben
Supervisor
1. FirstDr Stephan Tait
2. SecondProf Bernadette McCabe
3. ThirdDr Serhiy Marchuk
Sasha N. Jenkins
Institution of OriginUniversity of Southern Queensland
Qualification NameDoctor of Philosophy
Number of Pages163
Year2023
PublisherUniversity of Southern Queensland
Place of PublicationAustralia
Digital Object Identifier (DOI)https://doi.org/10.26192/z6723
Abstract

The aim of this thesis is to develop circular manure management strategies to reduce environmental risks and improve the sustainability of the Australian dairy farming sector. Circular technologies target the beneficial recycling of resources contained in dairy manure residues, such as nutrients and organic matter, for bioenergy production. Measurements are performed on liquid manure residues (effluent) from various dairy farms across Australia and reveal material amounts of nutrients, but there are no significant differences in nutrient concentrations amongst different dairy production system types (i.e. grazing vs. intensive dairies). However, there are notable differences in total nutrient capture rates (recovery potential) between different systems. Unfortunately, measurements confirmed dairy effluent is usually heavily diluted, making its transport, further processing, and beneficial use less viable. Cleaning strategies also affected dilution, requiring recovery methods such as solid-liquid separation. A modular solid-liquid separation technology is applied at full-scale at a commercial dairy. Without chemicals (lime and flocculant), only 25.9% particulate matter and 33.4% organic particle matter are recovered into the solid fraction, but the filtrate is more usable for irrigation. The solid fraction is also stackable and easily transportable for further processing and reuse. Lime and polymer flocculant enabled nitrogen and phosphorus recovery into the solid fraction, at ~54% and up to 91%, respectively. This provides circular options for farmers. A first biochemical methane potential of grazing dairy effluent is reported, specifically 161 LCH4 ·kg-1 volatile solids. Important effects of on-farm manure separation were also evaluated. This is important to evaluate renewable biogas recovery potential and is essential for sector emissions accounting. Overall, the data and findings of the thesis were invaluable to understand closed-loop system options, estimating recovery potential, and evaluating approaches to reduce manure-management greenhouse gas emissions across Australian dairy farms.

Keywordscircular economy; Carbonemissions; nutrient management; Dairy farming; Manure management; Resource recycling; Effluent treatment; Nutrient and energy recovery
Related Output
Has partResource recovery for environmental management of dilute livestock manure using a solid-liquid separation approach
Has partBiochemical methane potential of dairy manure residues and separated fractions: An Australia-wide study of the impact of production and cleaning systems
Contains Sensitive ContentDoes not contain sensitive content
ANZSRC Field of Research 20203099. Other agricultural, veterinary and food sciences
Public Notes

File reproduced in accordance with the copyright policy of the publisher/author/creator.

Byline AffiliationsSchool of Agriculture and Environmental Science
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