No one should be without clean water and sanitation
Water scarcity affects more than 40 per cent of the global population and is projected to rise. Over 1.7 billion people are currently living in river basins where water use exceeds recharge.
Sustainable solutions for wastewater management
Despite the multiple challenges of water scarcity, a number of innovative, technology-driven solutions are currently being implemented across the globe to ensure more efficient, sustainable use of this increasingly-precious resource.
Since agriculture is responsible for more than two thirds of water withdrawals globally, it’s vital that the sector uses water as efficiently as possible, with larger-scale deployment of more water technologies.
Precision irrigation combines mature technologies (i.e. irrigation systems) with innovative ICT solutions (such as sensors and GPS), enabled by automation and big data. More specifically, drip irrigation systems help farmers achieve better water-use efficiency (as well as contributing to better nutrient management and increasing crop yields), by transporting water from source through polyethylene tubing, and releasing it directly to plants by emitters, drip lines, sprayers, or sprinklers – using automatically-controlled pumps, valves and backflow preventers.
Additionally, incorporating irrigation controllers (such as micro-sprinklers or rainfall shutoff devices) allows for variable rate irrigation, balancing potentially different irrigation needs of the same field. Materials used for these parts are primarily plastic or brass, with brass components being more resistant to high pressure and direct sunlight. When combined with GPS technology and sensors (such as rain detection and soil moisture sensors, the antennae of which are made of copper, aluminium or stainless steel, alongside a power source which may be a solar panel or a battery), precision irrigation creates better understanding of field conditions, and ultimately better management of water needs (which may differ across different topography, soil texture, and type of crop).
Consumption of clean water in agriculture can be further mitigated by re-using treated wastewater for irrigation. Wastewater treatment is a multistep process occurring within large tanks, channels, chambers, and gasometers fitted with equipment made of concrete, steel, galvanised and stainless steel, and concrete lined ductile iron.
On an urban design level, sponge cities can help improve water availability (while also minimising urban flooding risk from increased stormwater runoff). The combination of nature-based solutions with grey infrastructure (such as green rooftops and water tanks, permeable pavements, bioswales and rain gardens) helps to collect and retain urban runoff and divert it back to natural storage, for later re-use in irrigation and cleaning.
Unlike large-scale, hard, impervious surfaces (which block the natural flow of water), materials with improved permeation (such pervious concrete, porous asphalt, paving stones, permeable interlocking concrete or clay brick, as well as loose gravel or stone-chippings without any binder) allow precipitation to infiltrate the surface areas in cities. Additionally, they act as layers of filtration, and thereby also contribute to increased water quality, capturing heavy metals and preventing them from being washed down to the soil.
If not newly built from the outset, a lot of the existent infrastructure is currently being retro-fitted with green roofs and permeable pavements in the largest cities globally – most notably in China.
On the demand side, smart water meters help to accurately track real-time water consumption at the level of households and businesses. Such information, collected through automated and remote reading of sensors and smart water efficient gadgets, enables end-consumers to make informed choices about water consumption, and can ultimately lead to water conservation. Additionally, the use of data from automated meter readings helps more accurate demand prediction, which in turn might inform optimisation of water treatment and pumping schedules.
At the same time, water utilities use smart monitoring infrastructure to improve efficiency of supply and enable easier detection of potential leaks along the water distribution networks. This in turn helps reduce strains on freshwater availability. In developing countries, for instance, preventing current daily rates of water leakages would be enough to serve nearly 200 million people.
Taken together, the potential for integrating the water sector with cloud computing, the Internet of Things (IoT) and big data is gaining in importance. The essential components of smart water meters are sensors (made from steel, brass, aluminium, and magnesium) that convert water flow to an electrical signal, allowing for temperature monitoring, low flow diagnostics and more accurate billing. The sensor, mounted on a printed circuit board, sends a signal to the microcontroller unit. The water flow data is then transmitted to remote information management systems via transmitters in the form of radio waves.
Depending on the design choice, the meter housing may be made of polymer composite, brass or copper alloy, while reflectors and strainers are typically made of stainless steel and composites, respectively. The meter is powered by a battery with lithium thionyl chloride chemistry, as this offers the highest specific energy and energy density of all existing battery chemistries.