Wastewater collection areas are comprised of merged sewage drainage basins that flow to a shared testing location for the COVID-19 wastewater study. The collection area polygons are published with related wastewater testing data, which are provided by scientists from Arizona State University's Biodesign Institute.   Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19. People infected with SARS-CoV-2 excrete the virus in their feces in a process known as “shedding”. The municipal wastewater treatment system (sewage system) collects and aggregates these bathroom contributions across communities.    Tempe wastewater samples are collected downstream of a community and the samples are brought to the ASU lab to analyze for the virus. Analysis is based on the genetic material inside the virus.    About the data:

• These data illustrate a trend of the signal of the weekly average of COVID-19 genome copies per liter of wastewater in Tempe's sewage. The dashboard and collection area map do not depict the number of individuals infected. 
• Each collection area includes at least one sampling location, which collects wastewater from across the collection area. It does not reflect the specific location where the deposit occurs.
• While testing can successfully quantify the results, research has not yet determined the relationship between these genome values and the number of people who are positive for COVID-19 in the community.
• The quantity of RNA detected in sewage is real; the interpretation of that signal and its implication for public health is ongoing research. Currently, there is not a baseline for determining a strong or weak signal.
• The shedding rate and shedding duration for individuals, both symptomatic and asymptomatic, is still unknown.
• Data are shared as the testing results become available.  As results may not be released at the same time, testing results for each area may not yet be seen for a given day or week. 
• The dashboard presents the weekly averages. Data are collected from 2-7 days per week. 
• The quantifiable level of 5,000 copies per liter is the lowest amount measurable with current testing. Results that are below the quantifiable level of 5,000 copies per liter do not suggest the absence of the virus in the collection area. It is possible to have results below the quantifiable level of 5,000 on one day/week and then have a greater signal on a subsequent day/week.
• For Collection Area 1, Tempe's wastewater co-mingles with wastewater from a regional sewage line. Tempe's sewage makes up the majority of Collection Area 1 samples. After the collection period of April 7-24, 2020, Collection Area 1 samples include only Tempe wastewater.
• For Collection Area 3, Tempe's wastewater co-mingles with wastewater from a regional sewage line.  For analysis and reporting, Tempe’s wastewater is separated from regional sewage.  

Additional Information

Source:  Contact: Zoe Aiello Contact email: Zoe_Aiello@tempe.gov Preparation Method:  Publish Frequency: Weekly or as data becomes available Publish Method: Manual Data Dictionary (pending)