Clean labware is important ensure safety and result reproducibility. Pro-actively thinking about your washing protocols can result in significant water savings, reducing costs and increasing sustainability.
Recently, we engaged in a lab audit at an industrial R&D lab. We noticed that a common way for these employees to clean beakers was to put them under a running tap. This method enabled the researchers to have time to engage in other tasks and return to a clean beaker.
We installed water meters on their taps to track their water usage and used them to compare different labware washing practices. We compared the cleaning of two 3 kg batches, each made in a 5 L plastic beaker with a Pitch Blade mixing impeller.
Procedure 1: (Old Washing Technique)
The product in the beaker was emptied into a waste drum, and put under a warm running tap until clean.
Result: Washing this beaker used 92 L of water and 4.5kWh energy. For their utility prices, it equated to €0.45/wash.
Note: To be honest, beaker not completely clean, but we did not have the heart to let the tap keep running anymore.
Procedure 2: (Good Washing Technique)
The product in the beaker was emptied into a waste drum, residual product was scraped with a spatula, beaker was then filled with cold water, left sitting for 10 mins and then manually washed with warm water using a sponge.
Result: This trial used 10.5 L of water and 0.385 kWh of energy.
Changing to this washing method saved 9x water and 12x energy. It pays to think carefully about how you are washing your glassware in the lab.
Small changes like the ones in the examples above can bring huge savings. Even more time, energy, and water savings can be recovered with the use of a dishwasher. Stay tuned.
The types of water available in the lab differ from lab to lab, but often include these following types,
City water – This is the water straight from municipal pipes, as you would receive in your home if you do not have a secondary purification system. Ion levels vary from day to day.
Soft water – This is city water which has gone through a filtration system to remove calcium and magnesium ions. This gives a more regulated water quality and does not leave as much lime-scale.
Demineralized (Demi/DI) water – This is soft water that has gone through ion exchange or electrodeionization to remove all ions.
Ultrapure (Milli-Q) water – This is Demi water that has undergone further purification through a reverse osmosis machine, often including UV irradiation. It has a resistivity of 18.2 MΩ.cm, TOC <10 ppb and bacterial count <10 CFU/ml.
Each successive purified water type requires significantly more water, more energy and more equipment and consumables to produce. A litre of Demi-water takes 3 litres of city water to produce. Many lab test methods and manufacturing operations ask for a specific water quality to ensure repeatability, safety, and good equipment maintenance. However, it is worth taking the time to analyze the operations in detail and understand why a lower quality water will not suffice.
In our research lab audits, we often see researchers washing their glassware with DI water and even ultrapure water unnecessarily. Generally, soft water, or even city water is sufficient for washing labware. A quick rise at the end with DI water can provide peace of mind. Most lab operations can be done with DI water and ultrapure water should be reserved for the most sensitive experiments, like dynamic surface tension. If you are going to autoclave the water for biology work, say for making bacterial media, assess your experiment carefully to determine if extra ions are really going to change your outcome.
In our industrial audits, we have also seen cases where a higher water quality is requested (e.g. DI water instead of soft water, or soft water instead of city water) due to an erroneous belief that the higher purity water has fewer microbes or lower micro-susceptibility. In such cases, it's better to use clean design, better cleaning & sanitization procedures and good lab/manufacturing practices. Often manufacturing specification limits (tolerances) are large enough to absorb the normal ion variations in city water. It is a bit of give-and-take and it may be more sustainable to look into the quality of the other raw materials or the process control strategies to keep your product in spec.
Single pass reactions wastes over a 1000 L of water for each reactions.
1. Waterless Air Condensors
2. Use a Recirculating bath
a) DIY Option: Fish Pump
Apologies, we are updating. We are in the process of re-uploading our content.
We're sure you've noticed the big changes to our website. We are currently updating. Apologies for the inconvenience. We are in the process of re-uploading our content.
Note: Questions and response may be slightly edited to fit website reading. Original text is kept where possible