“We will look anywhere and everywhere to collect data to make this invisible enemy more visible.” – County Executive Matt Meyer

April 2020 – New Castle County Executive Matt Meyer announced an innovative partnership with Massachusetts Institute of Technology-incubated startup Biobot Analytics. We began regular analysis of county and city of Wilmington wastewater to estimate the number of novel coronavirus cases in the sewer service area.

Click HERE for all up to date results. 

The partnership, initiated through New Castle County Public Works, initially surveilled only the incoming wastewater to the Wilmington regional wastewater treatment plant for traces of the novel coronavirus. This survey will expand to multiple pump stations throughout the county and to the three smaller wastewater treatment plants serving the lower portion of the county.

The County Executive has highlighted three goals of this partnership:

  1. Provide an estimate of individuals who are currently shedding the virus.
  2. Provide an estimate of trends, whether number of cases is increasing or decreasing.
  3. Provide an estimate of where active hotspots are located.
Sample Date Biobot estimates of 
positive cases
Positive Test Cases
(source: DPH)
Copies of virus % of population
April 15, 2020 30,400 974 81,059 6.1%
April 22, 2020 78,800 1,352 209,806 15.8%
April 29, 2020 63,400 1,717 168,863 13%

Results from wastewater sampling were anticipated to be higher than actual clinical test results since clinical testing is limited and is not reflective of the entire infected population. It does not include patients that are asymptomatic or that have mild symptoms who do not seek out testing.

Biobot will soon be implementing new testing procedures to account for variability in week-to-week sample results caused by non-human waste (i.e. industrial, etc) collected in the sample. Until such time, Biobot advises to view this data as reflecting the order of magnitude of infections. In other words, the number of cases in the Wilmington WWTP sewer service area is likely greater than 10,000.

We partnered with Biobot to add 10 new locations to the study. In addition to testing the Wilmington WWTP influent, samples were collected from MOT Water Farm, Delaware City WWTP, Port Penn WWTP and from 7 locations within the Wilmington WWTP service area that will better serve to break down the distribution of COVID-19 in this area above the C&D Canal. 

Data from the first two weeks of testing has been revised by Biobot.  As results come in for the upcoming weeks, we will update the data here, including the stations surveyed.