Hi Grant! Welcome to Permies! Thanks for being here for us this week.
I have a question about water cycling from Home to Bioshelter.
We are currently hooked up to the city sewer, but this week we found out our sewer pipe has settled and is basically not draining our water (no poo here, we have a compost toilet). We were thinking anyway of doing a greywater system and this seems like the perfect opportunity to do so. However, we live in a cold climate (Quebec), and I had a few questions and concerns.
1) We want to build a bioshelter next year next to our house. We would be installing earth tubes, which would allow us to keep the place at minimum 10 degrees C year-round. I was thinking of installing a greywater catchment tank in there to protect it from freezing in the winter while also serving as extra thermal mass for heat storage. The only problem would be what to do with the water after it has passed through a plant filtration system. It does solve our winter bioshelter irrigation problem, but I think we would make way too much water for the amount of irrigation we will need over the winter. Any ideas on what to do with the extra water?
2) I read somewhere that water from the kitchen sink shouldn't be included in a greywater system. Is this just paranoia about diseases? Won't it be ok once filtered through the plants?
Directing your excess greywater to an outdoor pond or retention basin would be your best bet. A sub-grade equalizer pipe can keep both an outdoor non-freezing water body (liquid volume below freeze level) and your water storage in a bioshelter (high tunnel/greenhouse) at the same level without fear of indoor water damage. Think of the equalizer pipe like a big water level. A properly engineered spillway should always be in place on any water-holding earthworks.
I would avoid kitchen greywater for direct irrigation of an edible plant system. (Tree fruit maybe, lettuce definitely not) We use soap on dishware (i do anyway) to wash pathogens from food and human cycles. Immediately reintroducing them to edible plant tissue isn't advisable.
Overall, I think that large-scale indoor aquaponics are typically a PVC-riddled farce. Nutrient-density of plants comes from soil, not 'media' and 'PVC'. A used stainless bulk tank or polyethylene tank works though.