Steps to circularity: Impact of resource recovery and urban agriculture in Seattle and Tacoma, Washington.

Capturing the value in urban residuals (food scraps and wastewater) is a critical component of urban sustainability and a circular nutrient economy. Food production in urban areas has also been recognized as an important component of urban health. Data from two cities (Seattle and Tacoma, WA) with active resource recovery and community garden programs were used to quantify nutrient recovery and food production potential.

Predictors of Phosphorus Leaching from Bioretention Soil Media.

The phosphorus saturation index (PSI) and P saturation ratio (PSR) were tested across a wide range of bioretention soil mixtures (BSMs) for their relationship to total and dissolved P in column leachate. The BSMs tested were made using different feedstocks including sand alone, food and yard waste compost, biosolids and yard compost, and high Fe biosolids. The PSI of the mixtures ranged from 0.

Stormwater Bioretention Systems: Testing the Phosphorus Saturation Index and Compost Feedstocks as Predictive Tools for System Performance.

A replicated column trial was conducted to evaluate the potential for the phosphorus saturation index (PSI) to predict P movement in bioretention soil mixtures (BSMs). The impact of compost feedstock on BSM performance was also evaluated. Three composts (biosolids/yard, yard/food waste, and manure/sawdust) were each brought to PSI values of 0.

Quantifying benefits associated with land application of organic residuals in Washington State.

This study was conducted to quantify soil C storage, N concentration, available P, and water holding capacity (WHC) across a range of sites in Washington State. Composts or biosolids had been applied to each site either annually at agronomic rates or at a one-time high rate. Site ages ranged from 2 to 18 years.