A new dairy processing plant in the United States has implemented the GWE waste water technology to benefit from improved biomass recovery and effluent quality, green energy from waste streams and reduced carbon footprint.
The Cayuga Milk Ingredients (CMI) processing plant in Auburn, NY was set up by Cayuga Marketing LLC, a collective of dairy farmers in the Finger Lakes Region, NY to reduce their milk-hauling costs while also greatly lowering transport emissions and carbon footprint from the shorter transportation distances.
The CMI plant went a step further to achieve optimum environmental and efficiency benefits by deciding to implement an anaerobic treatment process for their wastewater treatment facility.
The GWE technology used in the project is represented in Australia and New Zealand by CST Wastewater Solutions . Managing Director, Mr Michael Bambridge says the technology is suited to local dairy, beef and food processing companies who value environmental and profit benefits from production processes.
Mr Bambridge explains that the technologies installed at Cayuga, in addition to generating valuable biogas to replace fossil fuels, also provide exceptional benefits for biomass recovery, which are strongly applicable to Australasia. CST had recently installed GWE COHRAL technology at Oakey Beef Exports on Queensland’s Darling Downs, where it will extract green energy biogas from waste water streams, saving the client millions of dollars’ worth of natural gas currently consumed at the abattoir.
The CMI processing plant in the US selected Global Water & Energy (GW&E) as the engineering, procurement and construction (EPC) contractor to design, build and start up their new wastewater treatment facility. GW&E is the US branch of Global Water Engineering, created from a joint venture with Western Water Constructors, Inc.
GWE Engineer Ms Natascha Janssens explained that GWE’s FLOTAMET system was selected as the most suitable solution for wastewater treatment at the Cayuga dairy plant. The unique GWE system offers high rate anaerobic treatment with GWE’s ANAMIX reactor followed by biomass recovery in a combined sludge separation system consisting of GWE’s SUPERSEP-CF and GWE’s Dissolved Biogas Flotation (DBF) unit SUPERFLOT-BIOGAS.
The SUPERFLOT-BIOGAS is a dissolved biogas flotation (DBF) system used for high efficiency removal of anaerobic biomass from the effluent of an anaerobic treatment system. The anaerobic biomass is returned to the anaerobic system, thus increasing the sludge retention time. Such systems allow anaerobic reactors to be greatly reduced in size.
In Cayuga’s SUPERFLOT-BIOGAS system, the biomass is separated by means of flotation wherein solids are forced to float by fine biogas bubbles attached to the solids. These fine gas bubbles are created by recycling clean effluent, in which biogas is dissolved under pressure. After injection into the lower part of the flotation tank, the pressure release results in formation of fine biogas bubbles. Since biogas is used instead of air, the system has a completely enclosed design.
The Cayuga plant is designed to treat 950 m³/d of wastewater and 95 m³/d of whitewater, together resulting in a total COD (Contained Oxygen Deficit effluent pollution) load of 6,000 kg/d. Approximately 80% of the COD load and 85% of the BOD (Biological Oxygen Demand) load are removed in the FLOTAMET system, with the removed waste converted to biogas. This results in the production of up to 1,900 Nm³/d (at 75% CH4) of biogas, with an energy content of 590 kW.
Ms Janssens says the biogas will be used partially to heat up the wastewater in order to ensure optimal anaerobic digestion, avoiding the creation of an additional energy demand to the factory. In the second phase, the remaining biogas will be used to generate electricity to meet CMI’s goal to further decrease the carbon footprint of the factory.
The anaerobic effluent from the FLOTAMET system is treated in a conventional aerobic treatment by GW&E followed by a Dissolved Air Flotation (DAF) for solids separation. The aerobic polishing of the anaerobic effluent ensures that the discharge from the plant to the local sewer will meet the applicable strict discharge limits.