Most papers in the field of membranes and waters seem to start by telling us that water resources are under stress. This manifests itself in numerous ways and has been responsible for the development of the modern membrane industry. Water sources can be stressed both in terms of quantity and quality. Recently I have noticed an uptick in media interest in this issue. In the last month or so, there have been three BBC news stories on water which have caught my attention, one relating to not enough water, one to too much water and the third to both.
The first story related to Sao Paolo where I attended the IDA conference in 2017. At that time, I was surprised to see normal suburban streets with security gates and guards. As owners drove up, the gates would open automatically, and security personnel would have weapons at the ready. Residents have now taken self-sufficiency to a new level and secured their own water resources since they no longer have faith in municipal authorities to provide a reliable supply. Villas and apartment blocks have tapped into the groundwater aquifers directly, https://www.telegraph.co.uk/tv/2020/01/21/chris-packham-77-billion-people-counting-review-eco-polemic/. The unfortunate consequence of this is that in dry conditions the favellas run out of water, a new source of conflict and grievance.
The second story concerns the discharge of untreated sewage into UK rivers. Unfortunately for the English, the Victorian system of combined sewage overflows (CSO) means that when it rains, the volume of effluent maybe too high for the sewage treatment works, and in these circumstances the works are allowed to discharge the untreated sewage straight into the river. In fact, the Rivers Trust describes UK rivers as open sewers. Apparently, sewage discharges happened on more than 200,000 occasions in 2019 at around 6,500 locations.
Of course, the problem has been long known, but the fact that the more affluent in society living in leafy riverside residences are affected creates a news bombshell every now and again. In a recent incident, Feargal Sharkey of the Undertones, https://twitter.com/Feargal_Sharkey, has highlighted the problem, https://www.bbc.com/news/uk-england-berkshire-54024479. It is known that sewage discharges create a serious problem for the fish, but considering the amount of ‘forever chemicals’ used in society compared to 50 years ago, our source water is being posed with an ever increasing challenge which we are currently failing to meet. Many of the drinking water plants which use the affected rivers are not designed to remove the contaminants introduced by these sewage discharges. A proper explanation of this situation to the public would see people clamouring for wastewater reuse projects since the current status quo leaves some drinking water users dangerously exposed whereas reuse is controlled and safe.
The final story discussed the issue of England’s chalk streams. Periods of low rainfall mean that these streams can no longer meet abstraction licenses without degrading the environment. Affinity Water recently announced that it would cease abstracting from the River Chess with immediate effect to restore the environment, and other chalk stream reductions are planned, http://www.riverchessassociation.co.uk/news/85/57/Affinity-Turns-Off-The-Pumps.html. The CSO problem discussed in the second story can also create the opposite problem for chalk streams with excessive flows of poor water quality, but schemes are now being mooted that would treat wastewater so that it can be discharged safely into this environment.
In all three cases, membranes will have a key part to play, since barrier treatment of wastewater to allow recycle and reuse is the only way to address society’s resource constraints for the long term in an environmentally sustainable way. Reuse projects have become a reality in many areas of the world such as the south western US, Australia, Singapore and the Middle East, and hopefully, it won’t be long before a similar trend will occur in Europe.