By NZWB (Net Zero Waste Building) we mean in this article a building that reuse, recycle and/or valorize all the waste produced inside this building. This concept was created to fight against incinerators and undesirable landfills, and it has been adopted by many municipalities in New Zealand, Australia, New Scotland and the United States of America. The objective zero waste requires a change of habits to get rid of waste.
Based on a study that we have made for a specific kind of building (Net Zero Energy Building with an energy consumption of 50 à 30 KWh/m²) and on an average waste production for a family of 4 persons (issued from values of RECYC QUEBEC), different reusing, recycling and valorizing alternatives were analyzed : biological (composting, methanization), energetic (pyrolysis, gasification, incineration) and solids and fluids waste recycling. The conclusion has led to the following scheme:
From this scheme several recommendations are to implement:
- Low to very low energy consumption building (50 à 30 KWh/m²). This can be obtained by intensive design work to obtain an NZE building for example.
- The use of green roof and even green walls. About this, the RBQ (Régie du Bâtiment du Québec) has established a technical guide for green roof construction in 2015 and a documentary lunched by the CBDCa (Conseil du Bâtiment Durable du Canada) shows the evolution of this subject during the last 15 years in Quebec.
- The implementation from the design phase of the building of an integrated “recyclable materials sorting system” into the building
- The energetic valorization of the majority of the solid waste
- The biological valorization of the organic solids and fluids
Concretely, for a single home, we will still have 11% of the produced waste without valorization of any kind. This percentage include the “household hazardous residues”, bulky residues and construction, renovation and demolition residues, some textiles waste and miscellaneous waste.
In conclusion, the NZWB in a single home logic is not feasible. However, the concept has big chances to succeed in the logic of a big building and much more in a complete district, simply because the implementation of all the listed recommendations in addition to the actual best practices in energy (passive homes, smart building, NZEB and green building) are much more feasible.
But never forget the key to success for all of this subject, human behaviour and citizen engagement!