Civil Engineering, College of Engineering & Informatics, National University of Ireland, Galway1, Environmental Research Institute, University College Cork2, Teagasc Food Research Centre, Moorpark, Fermoy, Co. Cork3, Bioscience Research Institute, Athlone Institute of Technology4, Department of Civil, Structural and Environmental Engineering, Trinity College Dublin5
The abolishment of milk quotas in 2015 is expected to result in a 50% increase in milk production in Ireland by 2020. This increase in the volume of milk being processed along with stringent measures on emissions from the industry and growing commercial drive for operational efficiencies is driving the need for innovative technological and operational solutions within the dairy processing industry. In this context DairyWater, a new multi-stakeholder research project, is developing innovative solutions for the efficient management of water consumption, wastewater treatment and the resulting energy use within the country's dairy processing industry. This project has the potential to position Ireland at the forefront of European, or indeed international, research in this sector as it strives to make the Irish dairy processing industry more efficient and environmentally sustainable by reducing carbon footprints, energy and water use. This will, in turn, lead to greater potential for exports, increased international competitiveness for Irish products and stimulate job creation. DairyWater is led by Prof. Xinmin Zhan in Civil Engineering, College of Engineering and Informatics and the Ryan Institute at NUI Galway. The project also involves leading research groups at UCC, Trinity College Dublin, Athlone IT and Teagasc. The primary goal of the study is to efficiently and effectively treat wastewater effluent from dairy processing plants using a range of innovative biological, nanometerial-based and disinfection technologies. In parallel, the efficient use of water (and resulting energy costs) within the plants is also being explored. The four-year project has received 1 million euro funding from the Department of Agriculture, Food and the Marine.
Ireland is one of Europe's largest producers of cow's milk with an annual production of over 5,500 million litres. Currently, dairy ingredients and products comprise almost 30% of the Irish food and drink export market and, in 2013, dairy ingredients and products surpassed 3 billion euro for the first time (National Milk Agency, 2014). This export market is expected to increase due to the abolition of milk quotas and increasing international food demands. The project can be divided into three main research areas:
- Dairy wastewater treatment technologies;
- Water re-use and rainwater harvesting; and
- Environmental life cycle assessment (LCA).
Dairy wastewater treatment technologies
One of the most central aspects of the project is the development of novel technologies for the treatment of dairy wastewaters. When dealing with wastewater from dairy processing plants, the most problematic nutrients are nitrogen and phosphorous. The intermittently aerated sequencing batch reactor (IASBR) technology, developed at NUI Galway, will be investigated as previous studies dealing with pig production facilities have shown it has the potential provide an economical solution for nutrient removal. Initially, laboratory-scale experiments will be performed in order to determine the effectiveness of the technology in the dairy processing sector. Following this, a pilot-scale onsite system will be constructed at a selected dairy processing plant. This will give a greater insight into the performance of the IASBR technology at a more commercial scale.
The shift of the microbial ecological structure in laboratory-scale and pilot-scale IASBRs will be determined through molecular microbial ecology studies performed at the Environmental Research Institute, UCC, using advanced pyrosequencing techniques. This will aid in the development of bioreactor sampling regimes to obtain representative samples from established reactors and establishment of relevant sample storage and processing protocols. Additionally, this will give a greater understanding of the unique nutrient removal mechanisms of the IASBR technology, which will aid in significant increases of efficiencies in reactor design and operation, improve nutrient removal rates while decreasing costs and energy usage.
The use of nano-materials to improve the efficiency of wastewater treatment processes in this sector has not previously been well explored. Dairywater, at the Centre for Research on Adaptive Nanostructures and Nano-devices (CRANN) in Trinity College Dublin, will develop novel and low cost nano-materials that can greatly enhance treatment performance while reducing energy and operational costs. With the application of nano-materials within many engineering sectors, this could be one of the major leaps in the development of new and innovative engineered systems in the water and wastewater sectors. The effectiveness of the nano-material technology will be evaluated in both laboratory-scale reactors and full-scale systems.
Water re-use and rainwater harvesting
Along with the effective treatment of dairy wastewaters, a study into the efficient use of water within dairy processing plants is also being addressed within the project. This aspect will also include assessing the feasibility of utilising rainwater harvesting systems within the plants. In consultation with the advisory board, the existing and future challenges of industry are established. Laboratory-scale systems will be investigated and will initially comprise filtration technologies, pathogen removal technologies and barrier-type systems. The pathogen removal technologies are innovative pulsed UV systems, developed by Athlone IT and NUI Galway, which are designed to perform secondary treatment of the dairy wastewaters. The innovative technologies explored will be trialled at both laboratory-scale and at a demonstration site to accurately quantify their effectiveness.
Environmental life cycle assessment
Using the data obtained from the various dairy processing plants, an environmental life cycle assessment of dairy products manufactured within Ireland will be performed. This will methodically assess the industry from a lifecycle water usage, energy usage and greenhouse gas emissions perspective. Along with performing an assessment of Irish dairy products, an assessment of individual plants and the potential positive impact of novel technologies investigated in this project will be carried out. From these analyses, the true carbon footprint of dairy products from the greenhouse gas emission perspective can be estimated, which takes into account the global warming potentials (GWPs) of various greenhouse gases.
The project team are working closely with leading industry stakeholders. A project advisory board includes leading members of the dairy processing industry (Arrabawn, Aurivo, Carbery, Dairygold, Glanbia and Lakeland), and government funded bodies (Enterprise Ireland, the EPA and Teagasc). The industry partners will provide data and facilitate pilot scale activities during the project; thus enabling potential commercial benefits of this research to be realised. National Milk Agency. (2014) Annual Report and Accounts 2013.