Greywater recycling
Water is an increasingly scarce resource. As population increases, and climate change makes rainwater patterns less predictable, it is becoming more important that we reduce the amount of water that we consume and discharge into the sewerage infrastructure.
In addition, the treatment of water to make it suitable for drinking and other uses consumes a considerable amount of energy. Treating water to make it suitable for drinking just to use it for purposes that do not require this level of treatment, such as watering gardens or flushing toilets, is extremely wasteful.
Environmental concerns, utilities bills and the imposition of restrictions such as requirements for sustainable urban drainage systems and hosepipe bans means that people are increasingly looking to re-use or re-cycle water.
Typically water is categorised within one of three broad groups, with the degree of contamination increasing and so the number of suitable uses decreasing and the treatment requirement increasing:
- Fresh, potable water or ‘drinking water’ is sometimes referred to as ‘white water’.
- Wastewater from showers, baths, washbasins and washing machines that is not considered to be potentially dangerous, is referred to as ‘greywater’.
- Water from toilets that may be contaminated with hazardous material is referred to as ‘blackwater’ (or sometimes brown water, foul water, or sewage). Some definitions of blackwater also include water from kitchen sinks, dishwashers and waste disposal units which may contain food particles.
It is possible to collect greywater and, after treatment, use it for purposes that do not require drinking water quality, such as toilet flushing and garden watering. This greatly reduces the demand on mains water as well as reducing the volume of water discharged into sewage systems.
As well as conserving water this will also save users money on their water bills (if they have water metres installed). According to the Environmental Agency (2011), greywater recycling systems have the potential to reduce the amount of mains water used in the home by about a third.
The limitations of initiatives such as rainwater harvesting and greywater harvesting are that even though it reduces demand for mains water, it does not actually contribute to a reduction in water consumption. In addition, long payback times combined with small storage volumes mean it can be less effective than other water conservation measures.
[edit] Related articles on Designing Buildings
- Blackwater.
- Delivering water efficiency in commercial buildings: A guide for facilities managers.
- Drinking water quality.
- Environment Agency.
- Flood and Water Management Act.
- Green roof.
- Greywater recycling at the Millennium Dome.
- Hosepipe ban.
- Marine energy and hydropower.
- Non-wholesome water.
- Passive water efficiency measures.
- Planning for floods.
- Rainwater harvesting.
- Reed bed.
- SuDS - is there light at the end of the tunnel?
- Sustainable urban drainage systems.
- Types of water.
- Water consumption.
- Water management.
- Water quality.
Featured articles and news
Celebrating architecture's eloquent champions.
Unusual perspectives on 1960s’ thinking.
AI and the challenges to intellectual property
The legal landscape of adopting AI now and in the future.
Worrying landscape for Welsh construction SMEs revealed.
In recent risk factor analysis report completed by CIOB.
Construction Sport survey highlights risks of dehydration
Supporting construction workers to avoid dangers.
Can your business afford to ignore mental well-being?
£70 - 100 billion annually in UK construction sector.
Mental health in the construction industry
World Mental Health Day 10 October.
Construction awards provide relief in wake of ISG collapse
Spike in major infrastructure awards, housing up but short of targets, are ISG collapse impacts yet to come.
Biodiversity net gain with related updates and terms
Only 0.5% of applications subject to BNG in the context significant proposed changes to planning.
As political power has shifted from blue to red
Has planning now moved from brown to green?
The role of construction in tackling the biodiversity crisis
New CIOB Nature of Building digital series available now.
The Nature Towns and Cities initiative
Grants of up to 1 million for local councils and partners.
The continued ISG fall out October updates
Where to look for answers to frequently asked questions.
Building safety remediation programme for Wales
With 2024 October progress updates.
In major support package for small businesses.
Conservation and transformation
Reading Ruskin’s cultural heritage. Book review.
Comments
To start a discussion about this article, click 'Add a comment' above and add your thoughts to this discussion page.