Chris Grinstead: Cleaning Up - gleaming buses and saving water

For those of us in northern Europe, it’s hard to believe that water is scarce. Only recently has Ireland brought in any charges for water. Yet, the head of England’s Environment Agency has described droughts risk and possible water shortages as an “existential threat”. Meanwhile, tropical Singapore relies on a mix of rainfall, water imports, desalination plants and purifying wastewater.

So how do we become more water efficient?

Go-Ahead Singapore washes 400 buses a day operating an underground water recycling system installed by the Land Transport Authority.  Buses are first washed with filtered recycled water. A final rinse, using only a quarter of the water, uses fresh water. 

All the water is drained back into an underground storage tank and filtration system.  Go-Ahead Singapore teams maintain the system to ensure the water used on the first wash is clean. We are optimising this process to use a greater proportion of recycled water.

In England, our buses are generally washed daily and, at most sites, drive through bus washes recycle water.  For each bus wash, about 90% of the water is re-used.  We are exploring a range of measures to make every litre go further.

First, we want to get better at measuring the water we use by using data loggers or sub-meters to isolate consumption by the wash from wider water use within our depots. This is crucial to understanding, comparing and improving efficiency.

Second, we plan to optimise how we use our bus washes at each site. For instance, what’s the right mix of recycled and fresh water and the efficiency of the filtration. Do we get better results from reducing water pressure, by constricting spray nozzles or changing the number of nozzles that are open?

Third, we are examining when we wash our buses. In the summer – when there’s greatest strain on water resources – we can wash buses less frequently and still have gleaming buses. Alongside other measures to reduce water use from the sprays, Brighton and Hove Buses’ cleaning team will be reducing the frequency and putting in new systems to maintain quality.

We are proud of our work with suppliers to design in water efficiency. Go South West is working closely with suppliers to fix a long-standing inefficiency. Without intervention, 5-10% of water used in a bus wash can be lost when buses carry it away on their rooves.  Most bus washes now use a curtain that pulls the water off the top as it drives away. Go South West is optimising the process, by adjusting wash pad slopes and gully drains, to recycle as much water as possible. We are also working with bus manufacturers to minimise the water getting trapped in the first place.

By sharing our learnings across the group and system-wide improvements, all these steps will contribute to Go-Ahead Group achieving its target of reducing water use by 25% by 2025 – which is a crucial element of our overall strategy to adapt our business for global climate change