HONOLULU – Sludge. The final, unwanted byproduct of a toilet flush. The semi-solid stuff that even wastewater treatment plants send packing to the landfill. Unseen in the steel pipes snaking high on the exterior of Honolulu’s H-POWER plant, sludge is injected into a massive boiler where it joins the city’s trash in a roaring inferno. … Continue reading No Room for Waste: Honolulu’s Sludge Plant Points Toward More Sustainable Urban Development