Task 6 researchers publish article on the life cycle assessment of the dairy industry to determine the environmental impact of this sector

Task 6 researchers based at the National University of Ireland, Galway have been investigating the dairy processing industry in Ireland using life cycle assessment to determine the environmental impact of this sector.

Title: Assessing the environmental impact of the dairy processing industry in the Republic of Ireland

Authors: William Finnegan, Jamie Goggins and Xinmin Zhan.

Journal: Journal of Dairy Research

DOI: https://doi.org/10.1017/S0022029918000559


This Research Communication describes the methodology used and the subsequent results obtained for an assessment of the environmental impact associated with the manufacture of dairy products in the Republic of Ireland. As the Irish dairy industry changes and grows, it is necessary to have a benchmark of the environmental performance of the sector if it is to remain sustainable in the future. In order to estimate the environmental impact, life cycle assessment has been implemented, which has been structured in accordance with the International Organisation for Standardisation guidelines. In this study, the environmental impact categories assessed are terrestrial acidification potential, cumulative energy demand, freshwater eutrophication potential, global warming potential, marine eutrophication potential and water depletion. The main Irish dairy products have been compared across these environmental impact categories in order to derive meaningful results. It is identified that packaging materials, particularly for infant formula, and energy usage, across each of the life cycle stages, should be targeted as these are the most significant contributors to the overall environmental impact.

Congratulations to William and all co-authors.

Task 5 researchers publish article on the microbial ecology of IASBR systems treating dairy wastewater

Task 5 researchers based at University College Cork have been working with Task 2 researchers to perform molecular analysis to determine microbial community structures in the IASBR systems.

Title: Dominance of the genus Polaromonas in the microbial ecology of an Intermittently Aerated Sequencing Batch Reactor (IASBR) treating dairy processing wastewater under varying aeration rates

Authors: Beatriz Gil-Pulido, Emma Tarpey, William Finnegan, Xinmin Zhan, Alan DW Dobson and Niall O’Leary.

Journal: Journal of Dairy Research

DOI: https://doi.org/10.1017/S0022029918000572


In this Research Communication we investigate potential correlations between key bacterial groups and nutrient removal efficiency in an Intermittently Aerated Sequencing Batch Reactor (IASBR) treating synthetic dairy processing wastewater. Reactor aeration rates of 0·6 and 0·4 litre per minute (LPM) were applied to an 8 l laboratory scale system and the relative impacts on IASBR microbial community structure and orthophosphate (PO4-P) and ammonium (NH4-N) removal efficiencies compared. Aeration at 0·6 LPM over several sludge retention times (SRTs) resulted in approximately 92% removal efficiencies for both PO4-P and NH4-N. Biomass samples subjected to next-generation sequencing (NGS), 16S rRNA profiling revealed a concomitant enrichment of Polaromonas under 0·6 LPM conditions, up to ~50% relative abundance within the reactor biomass. The subsequent shift in reactor aeration to 0·4 LPM, over a period of 3 SRTs, resulted in markedly reduced nutrient removal efficiencies for PO4-P (50%) and NH4-N (45%). An 85·7% reduction in the genus level relative abundance of Polaromonas was observed under 0·4 LPM aeration conditions over the same period.

Congratulations to Bea and all co-authors for their second publication.

Task 4 researchers publish article on the application of UV-disinfection technology in the dairy industry

Task 4 researchers based at the National University of Ireland, Galway have been investigating the feasibility of water re-use and rainwater harvesting within the dairy sector with focus on UV-disinfection technology. They have published research on microbial characterisation and the effect of suspended solids on the efficiency of pathogen removal via UV-disinfection in dairy wastewater.

Title: Microbiological characterisation and impact of suspended solids on pathogen removal from wastewaters in dairy processing factories

Authors: Kelly Fitzhenry, Neil Rowan, William Finnegan, Xinmin Zhan and Eoghan Clifford.

Journal: Journal of Dairy Research

DOI: https://doi.org/10.1017/S0022029918000602


In this Research Communication we investigate the microbiological profile of 12 dairy wastewater streams from three contrasting Irish dairy processing factories to determine whether faecal indicators/pathogens were present and in turn, whether disinfection may be required for potential water reuse within the factory. Subsequently, the impact of suspended solids on the inactivation efficiency of Escherichia coli via two means of ultraviolet (UV) disinfection; flow-through pulsed UV (PUV) and continuous low pressure UV (LPUV) disinfection was analysed. Faecal indicators total coliforms and E. coli were detected in 10 out of the 12 samples collected at the dairy processing factories while pathogenic bacteria Listeria monocytogenes was detected in all samples collected at 2 out of the 3 factories. Salmonella spp. was undetected in all samples. The results also indicated that organic dairy wastewater solids had an impact on the performance efficiency of the PUV system and, to a lesser extent, the LPUV system. The findings indicate that the targeting of key pathogens would be required to enable wastewater reuse (and indeed effluent discharges if regulation continues to become more stringent) and that LPUV may offer a more robust disinfection method as it appears to be less susceptible to the presence of suspended solids.

Congratulations to Kelly and all who contributed.

Task 3 researchers publish article on the use of nano-materials for nutrient removal from dairy wastewater

Task 3 researchers based at Trinity College Dublin have published research on the use of nano-materials for the treatment of dairy wastewater.

Title: Potential of using synthesized nano-zeolite for ammonium and phosphate immobilization in dairy wastewater

Authors: Fei Gao, Liwen Xiao, Hongzhou Zhang.

Journal: Journal of Dairy Research

DOI: https://doi.org/10.1017/S0022029918000560


The studies described in the Research Communication aimed to describe the feasibility of using coal fly ash to synthesize nano-zeolite, and the ammonium and phosphate adsorption efficiencies of the nanomaterial in dairy wastewater. Chemical treatment of coal fly ash was conducted and changes observed. Samples treated with NaOH had an increased cation exchange capacity and P sorption index compared to the initial fly ash, due to particle modification from smooth surface to plate- and rod-shape crystals, referred to as nano-zeolite. Batch experiments were conducted by mixing coal fly ash and nano-zeolite with synthesized wastewater to study the effect of sorption time, pH values and dosage of nano-zeolite on ammonium and phosphate removal efficiency. The adsorption process reached equilibrium in a very short time (less than 60 min), which suggests a potential for fast immobilization of pollutants. The concentration of ammonium decreased from 118 to 35 mg/l (71% removal) while the concentration of phosphate decreased from 52 to 45 mg/l. The removal efficiency of ammonium was 36·6, 51·8 and 70·9% at pH 3, 7 and 10, respectively whilst that of phosphate increased dramatically with decreased slurry pH (92·1, 47·3 and 12·3% at pH 3, 7 and 10, respectively). Nano-zeolite could be a potential absorbent for fast immobilization of ammonium but not phosphate. Surface modification of nano-zeolite could be introduced in order to enhance the pollutants removal efficiency.

Congratulations to Fei and all involved.