sewage treatment solutions
How Does A Reed Bed Work?
Types of reed bed
Reed beds are an aquatic plant-based system which allows bacteria in the root to feed on the organic matter contained in the sewage. Three types exist:
- Vertical flow
- Horizontal flow
For a better sewage treatment solution, the vertical and horizontal flow types of reed bed often get combined. For each case, the effluent flows through the reed bed and percolates through layers of sand and gravel.
1. Vertical Flow
If you choose this option, you will typically install two vertical flow reed beds with only one of them operating.
They use aerobic organisms, which use oxygen, to break down pollutants, turning them into nitrates. In order to prevent blocking and make them function more efficiently, you can swap from one reed bed to the other, usually every few weeks.
Overall, reed bed maintenance is basic; you need to keep an eye on all the plants. Thus, there is a meager, even nonexistent maintenance cost.
2. Horizontal Flow
A horizontal flow bed is usually installed after a vertical one and has anaerobic organisms, which don’t require oxygen to turn nitrates into nitrogen gas.
If you are only treating greywater (laundry, tap water, etc.) you won’t need this bed, unless you discharge to a pond which requires better quality sewage treatment.
How is a reed bed sized and designed?
1. VERTICAL FLOW
Vertical flow reed beds require a slope of at least one meter and a half, and a surface area of about two square metres per person served. The more house occupants, the more the required size per person will reduce. The calculation of the necessary area is based on the assumption that one person will produce, on average, 200 litres of sewage per day.
Grey water-only reed beds are about 30% smaller than those for all sewage because about 30% of domestic wastewater gets flushed down the toilet.
2. HORIZONTAL FLOW
Horizontal flow reed beds require about one square meter per person served, with a minimum of six square metres. A settlement tank should be installed between vertical and horizontal flow reed beds to separate the solids from the liquids. This tank won’t need emptying often.
How to install a reed bed?
Reeds will fully establish in two/three years. Nonetheless, in the meantime, the sewage treatment system can still be used as the reeds need the nutrients to grow, and the beds can function without reeds. The reeds are only there to aerate and provide frost protection.
The grade of the pea gravel should be around five-ten millilitres. It’s more than enough as you only need a thin layer to support the sand above. A layer of coarse gravel should get added also. The gravel should ideally be washed and graded to 20mm (at a minimum).
If aeration pipes are included, a couple is sufficient for a small reed bed. You can drill 10mm holes every 20cm along the length of some 100mm tubing.
It can take up to four weeks to install a reed bed. It depends on the size, the materials used, and if you hit bedrock. If you decide to do the installation on your own, it can cost several thousands of pounds: for the hire of an excavator, pipes, and so on. If you decide to hire a professional to install your reed bed, it can cost over £10 000.
Therefore, reed beds are a costly but environmentally friendly solution. They provide high-quality, effluent treatment without using electricity. However, if you are looking for a simple, cost-effective, reliable, easy to install, and low-maintenance solution, we recommend you to choose our package sewage treatment plant, Tricel Novo.
If you have any questions, don’t hesitate to contact us. We will be more than happy to help you with your request.
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Tricel Environment UK
A trading brand of Dewey Waters Ltd.
Heritage Works, Winterstoke Road, Weston-super-Mare, BS24 9AN, United Kingdom.
Tel: +44 (0)1934 422 311