Appropriate Technology, Courses and Events, Sunseed News

A new pond for our wastewater system!

Sunseed’s Appropriate Technology co-coordinator Piotr explains how we built a beautiful pond as part of our eco-friendly wastewater treatment system.

Last weekend of 16-17 April at Sunseed we conducted a workshop on Ecological Wastewater Treatment, facilitated by the coordinators of Sunseed and the Paissano collective – friends of Sunseed and big water treatment and purification enthusiasts. We invited both Sunseed volunteers and people from the Almería province interested in learning how to build a low cost ecological wastewater treatment at home. The financial contribution to the course was voluntary, after assuring the basic costs of food and accommodation.
Among some 10 participants of the course we undertook a practical project to improve the last stage of our wastewater system and beautify the space around the path which leads to the famous pool of Los Molinos. We have built a new pond!

Wastewater treatment pond

Ponds are often installed as the last stage of wastewater treatment systems with constructed wetlands (reed beds). They serve a basic function of storing the treated water in order to reuse it for irrigation, as well as to create a natural habitat for fauna and flora, thus increasing the biodiversity of the environment. Our pond consists of an infiltration area with gravel (planted with water treatment plants – macrophytes) and a deep area where in the near future we would like to plant floating macrophytes. It stores 1200 liters of water and is equipped with an overflow system to irrigate an educational self-irrigating garden in the future. We will leave the garden design to the participants of a Permaculture Design Course held by Sunseed between the 1st and 15th of May.

Construction Stages

First things first, we had to clean the construction area previously occupied by a ghost pond, which with time was filled with mud and has been taken over by the ubiquitous cane plants. The rhizomes of cane had pierced the waterproof layer of plastic, which had thus stopped serving its function.

Digging the wastewater pond
Preparing the wastewater pond

Cleaning the old pond area – a lot of mud and cane rhizomes…

After the digging we interactively and collectively designed the form and shape of the new pond. We decided to construct a division wall which allows to have a natural slope around it. Subsequently the ground was compacted and the overflow tube installed.

Installing overflow tube

Installation of the overflow pipe

We waterproofed the pond with EPDM liner, a very strong and flexible material used widely in this type of application. Around the pond we placed stones and built a small dry wall to protect the pond from mud falling inside during heavy rains. Then we filled the shallow area with gravel. Next comes the exciting part of filling it with water and planting the plants.

Guy and Blanca with pond
Petr and pond

Keeping in mind the future habitants of our pond we have created a small cave, a future house of a very happy frog.

Pond plants 1
Finished pond

With the completion of the construction of the pond we have only opened it up for the future improvements and changes. Many Sunseed volunteers will have the opportunity to experiment with the planting of plants, elaboration of a self-watering garden with purified water and the aesthetic modifications of the pond itself. As always in Sunseed, a project never finishes, it evolves…

For more information on similar future projects and courses, contact Sunseed’s Appropriate Technology co-coordinator Piotr on