Environmentally sustainable Laboratory water purification
Satisfying laboratories’ demand for large quantities of pure (Type 2) water while addressing environmental sustainability is a challenge that has been successfully tackled by Merck Millipore with its Elix® 3 water purification system.
Whatever purifying process is chosen, removal of ions, organic and suspended particles, micro-organisms, gas and other contaminants involves some ‘wastage’ of water. It also consumes energy and produces CO2. The aim of the Elix® 3 system has been to deliver the water quality required but reduce the consumption of natural resources and the contribution to global warming.
To date, the standard approach to water purification has been to use distillation and deionisation units. The new process patented by Merck Millipore and applied to Elix® systems combines electrodeionisation (EDI) technology with reverse osmosis (RO). Crucially, this procedure avoids deterioration of the resin bed by removing the need for special maintenance or chemical regeneration. Instead, an electric current, requiring very little energy, continually regenerates the ion-exchange resins.
In a recent study the environmental impact of the Elix® 3 system was compared with that of a traditional distillation system. It calculated the cost to the environment of producing 20 litres of pure water per day while operating for 6.7 hours per day, 20 days per month, over a full year, which is considered typical of an average laboratory’s needs.
The Elix® 3 system used 15 litres of water to produce 3 litres of pure water per hour, while the distillation system used 26.6 litres to achieve the same.
Energy consumption to produce 3 litres of pure lab water per hour was 0.160 kWh for Elix® and 1.65 kWh for distillation.
To operate the Elix® 3 system for a year also requires two Progard® S2 purification cartridges. Producing and distributing each of these consumes an additional 107.8 litres of water and 39.6 kWh of energy while generating 5.9 kg of equivalent CO2.
Taking all of the data into consideration, researchers calculated that distillation would consume almost twice as much water annually as the Elix® system: 44,880 litres compared to 24,270.
Annual energy consumption would be more than four times higher for distillation: 2,614 kWh compared to 617.
And as an indication of global warming potential, the Elix® system would produce just 199 kg of CO2 each year compared to the distillation system’s 944 kg.
So on all measures of environmental sustainability the Elix® 3 system is clearly a much better option than distillation. Meanwhile, its lower running costs and its ability to operate constantly with very little maintenance also make it attractive in terms of financial costs.
Date added: 2015-05-25 12:15:49