Geomembrane for effluent pond in New Zealand

Projectname: Dairy farm New Zealand
Projectdate: 2014
Products: 1 650 m² smooth HDPE geomembranes 1.5 mm thickness

New law - geomembranes in dairy cattle farming

With the number of dairy cows continuously increasing in the past decades, milk products became New Zealand’s largest export earner. In 2009 dairy products accounted for 21 % of the total merchandise exports.

Cows are outdoors year round. Twice a day they are brought into the milking shed. Regularly the milking shed and the yard around it have be to cleaned. This leads to approximately 70 litres of water contaminated with effluent per cow each day.

Effluent ponds

2013 wurde in Neuseeland ein neues Gesetz zum Schutz der Umwelt verabschiedet, welches den Bau von Abwasserbecken bei Milchviehanlagen mit einer bestimmten Größe gefordert hat.


All sealed

basins function to our complete satisfaction.


This enables the farms to collect the waste water during winter time and use the additional water during summer for irrigation. The ponds must have at least the size to store the water generated in 90 days. Typically the effluent ponds have a surface size between 1 500 m² and 5 000 m².

To build effluent ponds, first the subsoil has to be prepared and a drainage system has to be installed below the pond. It is topped off with a layer of stone free, fine material (e.g. earth, clay, sand). Then a nonwoven geotextile and finally the geomembrane (1.5 mm HD-PE) is installed. The stone free layer and the geotextile is essential to protect the geomembrane and ensure a long life-time.

HDPE geomembranes

To effectively protect the environment it is essential to have absolutely leak tight effluent ponds. Due to the excellent properties HDPE geomembranes supplied by AGRU have proven most suitable for this application. Among others the most important advantages are the high toughness and the excellent strength which lead to a robust effluent pond. Also important is the ease of installation and excellent weldability. The installation is carried out in a professional way by AGRU New Zealand and Agruline Ltd.

The first figure shows the effluent pond at Walters farm in Otaua during construction in February 2014. Up to date many effluent ponds have been successfully finished using HDPE geomembranes from AGRU. All of them are operating to the satisfaction of the owner and are expected to do so for many years to come.