Can waste equal food? Exploring the urban opportunities and limitations in advancing a closed loop practice of phosphorus; the case of Wageningen, the Netherlands
Phosphorus (P) plays a key and unique role in the growth and functioning of life on earth, yet it is marked by critical concerns such as (economic) scarcity and a growing demand for P that needs to be met. With P being an important component of fertilisers, combined with a growing world population, access to sufficient P is crucial for food security. Despite these concerns, large amounts of P are currently (unnecessarily) lost and do not return to the human food system. Moreover, losses of P into water bodies cause eutrophication that has detrimental effects on ecological systems. Overall, these issues clearly illustrate a need for sustainable P management. There has been much focus on the agricultural sector, yet the role and contribution of urban areas in these global P issues should not be overlooked. With most of the worldwide population being urban dwellers, it is urban areas that drive the demand for food production (and subsequently P) and therefore become so-called ‘P hotspots’.
This thesis therefore examines infrastructural limitations and opportunities for (small) urban areas to foster P reuse (compost and sludge from anaerobic digestion) and recycling (struvite) through its waste management system - consisting of waste water (WW) and municipal solid waste (MSW) - that determines the flow of P. In doing so, the city of Wageningen, the Netherlands was chosen as a case-study and limited to P found in food related flows only, which represents the largest flow of P in an urban area. The research conducted was two-fold. First, a quantitative substance flow analysis (SFA) was used to identify current P losses from the urban system. Subsequently, feasible alternative strategies (from the perspective of the municipality) for altering the waste management system to enhance P reuse and recycling were researched and their impact was estimated. By doing so, limitations and opportunities for the municipality to increase P reuse and recycling could be identified. Main data collection methods were literature search, thirteen in-depth interviews, other personal communication (email and phone) with thirty-two actors as well as two site visits.
The SFA of Wageningen with the base year of 2012 shows that the distribution of P flows (in t/yr) in the waste stream was nearly equal for WW and MSW. Of the total P input into Wageningen, which amounted to 51.2 t P/yr, there was no P recycling, and P reuse accounted for 6 % of total P input (of which 80 % was due to pet flows). This means 94 % of all P input is lost. The SFA results show the importance of considering P flows related to pets in urban areas (accounted for 24 % of total P input). The proposed strategies enhance P reuse and recycling only about 1 t P/yr.
Limitations and opportunities were found to be determined by the level of influence, incentive and capacity of the municipality to act. On both the national and local level, the strongest opportunities for the municipality appeared to reside in MSW (enhancing the separation rate of organic waste). On a national level, market and regulative forces push for organic waste separation and thereby provide incentive to take action on an urban level. On the local level, the municipality has more influence on MSW management in comparison to WW, where this proved to be limited. Furthermore, results show that it could be beneficial for the municipality to improve its connectedness to other actors (on regional or national level) for either collaboration or knowledge sharing. This connectedness can enhance the overall ability of (especially small) municipalities to implement appropriate measures on the level of infrastructure to foster P reuse and recycling. Overall, this thesis shows that urban areas definitely have a role (and responsibility) to play given the fact that most of the P (from food) is still being lost.
This thesis therefore examines infrastructural limitations and opportunities for (small) urban areas to foster P reuse (compost and sludge from anaerobic digestion) and recycling (struvite) through its waste management system - consisting of waste water (WW) and municipal solid waste (MSW) - that determines the flow of P. In doing so, the city of Wageningen, the Netherlands was chosen as a case-study and limited to P found in food related flows only, which represents the largest flow of P in an urban area. The research conducted was two-fold. First, a quantitative substance flow analysis (SFA) was used to identify current P losses from the urban system. Subsequently, feasible alternative strategies (from the perspective of the municipality) for altering the waste management system to enhance P reuse and recycling were researched and their impact was estimated. By doing so, limitations and opportunities for the municipality to increase P reuse and recycling could be identified. Main data collection methods were literature search, thirteen in-depth interviews, other personal communication (email and phone) with thirty-two actors as well as two site visits.
The SFA of Wageningen with the base year of 2012 shows that the distribution of P flows (in t/yr) in the waste stream was nearly equal for WW and MSW. Of the total P input into Wageningen, which amounted to 51.2 t P/yr, there was no P recycling, and P reuse accounted for 6 % of total P input (of which 80 % was due to pet flows). This means 94 % of all P input is lost. The SFA results show the importance of considering P flows related to pets in urban areas (accounted for 24 % of total P input). The proposed strategies enhance P reuse and recycling only about 1 t P/yr.
Limitations and opportunities were found to be determined by the level of influence, incentive and capacity of the municipality to act. On both the national and local level, the strongest opportunities for the municipality appeared to reside in MSW (enhancing the separation rate of organic waste). On a national level, market and regulative forces push for organic waste separation and thereby provide incentive to take action on an urban level. On the local level, the municipality has more influence on MSW management in comparison to WW, where this proved to be limited. Furthermore, results show that it could be beneficial for the municipality to improve its connectedness to other actors (on regional or national level) for either collaboration or knowledge sharing. This connectedness can enhance the overall ability of (especially small) municipalities to implement appropriate measures on the level of infrastructure to foster P reuse and recycling. Overall, this thesis shows that urban areas definitely have a role (and responsibility) to play given the fact that most of the P (from food) is still being lost.
Reference
Jenkins, A. (2014). Can waste equal food? Exploring the urban opportunities and limitations in advancing a closed loop practice of phosphorus; the case of Wageningen, the Netherlands., Wageningen University, Wageningen.