SOLVE magazine Issue 01 2020 - Page 19

SUSTAINABILITY AND THE ENVIRONMENT: WASTEWATER Humans are creatures of waste. Disposing of what we produce, naturally and industrially, has always challenged us; the lazy side of human nature needs to be shepherded into clean routines by etiquette, laws or civil infrastructure. Before the advent of sewerage systems, for example, night soil was tipped into the street without a second thought. Consequently, the science of waste disposal straddles psychology as much as civil engineering, and today this science also encompasses the new imperative to make all human activity more environmentally sustainable. One of the educational resources that environmental technologists like Professor John Williams tap into is curiosity: just exactly where does the plughole lead? Professor Williams recounts the time he took students to a wastewater treatment works, where stage one is the screening-out of solid rubbish. Curiosity knows no limits when it comes to our waste and where it goes: “What’s the worst thing you’ve found on the screens?” asked one student. “Fingers,” the Process Scientist guiding the tour replied. As Professor of Environmental Technology at the University of Portsmouth, John Williams’s research focuses on water engineering, with a particular emphasis on water quality, and this means doing a lot of work on understanding how wastewater systems are misused by people. The discovery of fatbergs that build up and block sewers came from this research. Fatbergs develop when fats, oils and greases from domestic and commercial kitchens are poured into the sewage system. They react with calcium and other ions that are present in sewage and create a form of heavy soap – but not one you would choose to wash with. “People put all kinds of things down the drain which they shouldn’t,” Professor Williams observes. “It’s our flush-and-forget mentality. “People don’t consider what the infrastructure is for and how they connect with the environment through this infrastructure.” He says a particular challenge is harmful materials too small to see, let alone screen. These include traces of pharmaceuticals in urine, and microplastics – tiny synthetic fibres that are stripped from clothing in the turbulence of washing machines and drain away with the dirty water. A Portsmouth PhD student, Serena Cunsolo, is working on a nationwide project to develop ways of finding out what happens to these microplastics during sewage treatment, and where they finish in the environment. As with all micropollutants there are serious concerns about how much is consumed by fish. Professor Williams says breaking through the public awareness barrier is key to reducing this risk: “If people can relate to what they’re doing in the kitchen and, for example, start pouring fat into a container instead of down the drain, that’s a step forward.” To facilitate this, the University of Portsmouth has laboratories at a sewage treatment plant. This enables researchers to run pilot trials using real sewage, create large datasets and analyse samples in on-site laboratories. The power of reeds Professor Williams is a world authority on the development of low-impact, sustainable technologies to deal with dirty habits, including contaminated landscapes. In Egypt, South America and the UK, he has worked with constructed wetlands, using reed beds to treat polluted water. This is a natural process ideal for locations or economies for which large-scale mechanical and chemical processes are not practical or affordable. “Reed beds have application where there is no infrastructure to support processes that are energy and mechanically intensive.” He says reed beds are ideal for ‘environmental engineering’ because reeds have a mechanism to transfer oxygen from their leaves to their roots. Root zones modified in this way become intensive sites of microbial activity: “If you plant reeds in a swamp which has no oxygen in it, the reed roots will become oxidised, and that promotes the breakdown of organic compounds.” Reeds can grow under flooded conditions or hydroponically in gravel, making them ideal for healing contaminated sites. “We’ve had reeds growing in what we believe are UK-record levels of petroleum hydrocarbon pollution in sediment, with the reeds still growing happily and cleaning up the sediment by stimulating microbial activity.” Understanding and acceptance Professor Williams recognises that making change happen is, in many ways, a challenge of psychology. “In lower-income countries,” he observes, “people have a greater connection with the environment, because they’re using its resources more directly. “Whereas in the UK, there’s a barrier. People have switched off from the idea of needing to live with water because there’s a sense that it’s fully managed … that, for example, you can build in a low-lying area because we have drainage schemes that pipe the water away. But that’s just another example of relocating the problem.” Professor Williams uses this example to offer a more sustainable alternative for housing developments in such areas: adding wetlands and ponds into which water can drain naturally. He points out multiple benefits: “As well as flood control, you’ve got water quality improvement as it passes through the wetlands, improving river water quality and downstream habitats. “Also, I’ve found people like having habitat within a housing development. Having green space encourages people to be more active. It also improves air quality – the benefits can go on and on and on. “Yet some resist the idea because the presence of ponds or wetlands lead to assumptions that natural water bodies pose a flood risk; people don’t realise that their presence actually makes such an event less likely,” he says. “So sustainability solutions for fitting housing to natural landscapes, or for wastewater generally, need psychology as well as science and civil engineering. We need people to understand that the plughole is not the end of the matter … it’s just the beginning.” ISSUE 1 / 2020 19