Hard Bargain Farm Greywater Treatment

A low-energy and simple soil-based greywater treatment/dispersal system designed to Living Building standards sustainably manages water while furthering understanding and stewardship of Potomac River watershed ecology.

The Alice Ferguson Foundation connects people to the natural world, sustainable agricultural practices, and the cultural heritage of the Potomac River watershed. Their 330-acre Hard Bargain Farm serves as an environmental education center that provides hands-on activities, models, and field studies amid a diverse range of habitats. When the Foundation needed a new education building, they pursued Living Building Challenge (LBC) certification and turned to Biohabitats to design a net zero greywater system. The farm’s composting toilets handle sanitary wastes with minimal water demands, but greywater required treatment and a conventional septic system was prohibitively expensive due to site soil constraints and equipment needs.

Biohabitats designed and permitted a low energy system to safely recharge treated greywater back to the aquifer. Greywater is collected, settled, equalized, and filtered. It then enters a subsurface drip irrigation system that slowly treats it through biologically active soils and plant roots in a meadow. Native grasses within the land application field make the system blend into the farm’s natural landscape. Harvesting, recycling, and balancing water and nutrients is a key component of LBC certification, but regional regulations do not always align with LBC goals. Biohabitats collaborated with local regulatory authorities to introduce them to this kind of innovation.

Engineered to operate year-round even through freezing temperatures, the system treats up to 1,840 gpd and disperses it to recharge groundwater and improve water quality in the Potomac. It is also an educational model that teaches integrated water strategies and the connections between human actions and local ecology.

TAGS

• Analysis+Planning
• Assessment+Monitoring
• Design