The Circular Water Economy in Action
A variety of locations are implementing circular economy concepts that promote the reduction of water consumption, reuse of water, and recovery of materials from wastewater.
Reducing water consumption
Water utilities are using a variety of demand management tools to reduce water consumption including pricing of water, reducing leakages in the systems, metering all customers, using subsidies and rebates to encourage the installation of water-efficient technologies and appliances in homes and businesses, and awareness initiatives that educate the public on the need to use water wisely. The overall aim of demand management is to modify the attitudes and behavior of customers towards water during both normal and atypical times.
Scottish Water’s Water Savings Calculator
Scottish Water provides customers with an online Water Savings Calculator to determine their actual water usage. At the start, customers get to personalize the questions to suit their homes, so if they do not own a car the customer will not be asked how often they clean it. Once completed — it takes around 5 minutes — the user is provided with their own personalized water, energy and spend profile, a few free water-saving products that are easy to install, along with a series of tips on what can be done to save water. For example, fixing a dripping tap can save as much as 48 liters of water a day, or 17,500 liters of water a year and shaving 1 minute off your shower could save £15 in energy bills and a further £15 in water bills per year or £120 saved a year for an average 4-person household.
Reuse of water
Water reuse involves collecting, treating, and reusing wastewater (recycling). It can also involve the reuse of greywater or rainwater in houses or buildings. Recycled water can be used for non-potable uses e.g. industrial, agricultural, etc. If treated appropriately, recycled water can be blended with surface or groundwater to increase supplies. This reduces the economic and environmental costs related to establishing new water supplies.
Pure Water San Diego
To enhance San Diego’s resilience to drought, climate change, and natural disasters, the city has launched Pure Water San Diego which is a phased, multi-year program to provide one-third of the city’s water supply locally by 2035. The program will use proven technology to clean recycled water to produce safe, high-quality drinking water and provide a reliable, sustainable water supply. Currently, only 8 percent of wastewater is recycled with the rest being treated and discharged into the ocean. The Pure Water Program will transform the city’s water system into a complete cycle in which wastewater will be treated to recycled water standards at an existing water reclamation plant, before being sent to a Pure Water Facility. The purified water will then be sent to an existing reservoir and blended with imported and local water supplies. After this, the mixed water will then be treated at an existing drinking water treatment plant, before distribution to customers.
Recovery of materials from wastewater
Traditionally, wastewater is seen as a burden that needs treating and disposing of. However, wastewater is a source of valuable resources including energy and nutrients. The positive impact of recovering resources from wastewater is additional revenue streams for utilities and mitigation of emissions.
Berliner Wasserbetriebe recovering resources from wastewater
Berliner Wasserbetriebe’s Schönerlinde sewage treatment plant is turning sewage sludge into sewage gas to generate power and heat. Additionally, the utility has constructed three wind turbines, with a capacity of 2 MW each, as well as two micro gas turbines to complement the plant’s CHP unit. Overall, around 84% of the energy required by the plant is produced internally, saving up to 13,000 tons of carbon emissions per year. Berliner Wasserbetriebe has also developed a patented process for recovering phosphorus from its sewage treatment plants. The recovered phosphorus is sold under the brand name ‘Berliner Pflanze’ (Berlin Plant) to horticulture and agriculture producers in the surrounding areas of the city. Several years ago, Berliner Pflanze won the GreenTec Award for environmentally-friendly recycling products.
The take-out
The circular water economy is not an abstract concept, it is alive and growing globally.
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