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

Abstract

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

Abstract

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

Abstract

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.

Task 2 researchers publish two articles on investigations into IASBR technology for the treatment of dairy wastewater

Task 2 researchers based at the National University of Ireland, Galway have published two papers on the use of Intermittently Aerated Sequencing Batch Reactor (IASBR) technology for the treatment of dairy processing wastewater. The papers detail investigations performed at both laboratory and pilot-scale to validate the use of this technology within the dairy sector.

Paper 1 title: Efficient treatment of dairy processing wastewater in a laboratory scale Intermittently Aerated Sequencing Batch Reactor (IASBR)

Authors: Peter Leonard, Emma Tarpey, William Finnegan and Xinmin Zhan.

Journal: Journal of Dairy Research

DOI: https://doi.org/10.1017/S0022029918000584

Abstract:

This Research Communication describes an investigation into the viability of an Intermittently Aerated Sequencing Batch Reactor (IASBR) for the treatment of dairy processing wastewater at laboratory-scale. A number of operational parameters have been varied and the effect has been monitored in order to determine optimal conditions for maximising removal efficiencies. These operational parameters include Hydraulic Retention Time (HRT), Solids Retention Time (SRT), aeration rate and cycle length. Real dairy processing wastewater and synthetic wastewater have been treated using three laboratory-scale IASBR units in a temperature controlled room. When the operational conditions were established, the units were seeded using sludge from a municipal wastewater treatment plant for the first experiment, and sludge from a dairy processing factory for the second and third experiment. In experiment three, the reactors were fed on real wastewater from the wastewater treatment plant at this dairy processing factory. These laboratory-scale systems will be used to demonstrate over time that the IASBR system is a consistent, viable option for treatment of dairy processing wastewater in this sector. In this study, the capacity of a biological system to remove both nitrogen and phosphorus within one reactor will be demonstrated. The initial operational parameters for a pilot-scale IASBR system will be derived from the results of the study.

 

Paper 2 title: Efficient treatment of dairy processing wastewater in a pilot scale Intermittently Aerated Sequencing Batch Reactor (IASBR)

Authors: Peter Leonard, William Finnegan, Maria Barrett and Xinmin Zhan.

Journal: Journal of Dairy Research

DOI: https://doi.org/10.1017/S0022029918000596

Abstract:

This Research Communication describes the initial operation of a pilot-scale intermittently aerated sequencing batch reactor system, which is located at an Irish dairy processing factory. Laboratory-scale research has facilitated the design specifications and operational parameters necessary for the construction and running of a pilot-scale. Laboratory scale research was necessary prior to the pilot scale system to ensure high quality treatment and nutrient removal efficiencies. The pilot system operates with a hydraulic retention time of 4 d, a solids retention time of 16 d and a cycle length of 12 hours. There are 4 non-aeration and aeration phases within the system’s react phase. This system has a 3000 l working volume, treating 375 l of wastewater per cycle, 750 l daily. The system was seeded from an aeration tank at the dairy processing factory where the unit is located. The system is operating with the goal to remove both nitrogen and phosphorus from the wastewater biologically, reducing the need for chemical treatment. Currently, the system is performing with high efficiency, treating the wastewater to an acceptable level according to the Irish Environmental Protection Agency for discharge into surrounding water bodies. Therefore, the initial removal results demonstrate this technology’s suitability for the treatment of high strength dairy wastewaters.

Congratulations to Peter and all co-authors.