Smart sampling for enhanced disease monitoring

Deep Autosampler Live Monitoring System (DALMS) by Nm3 Tech and the National Environment Agency

Wastewater, often overlooked, contains information valuable for monitoring the transmission of infectious diseases. NEA’s novel wastewater-based surveillance strategy demonstrated its effectiveness in studying disease trends and supported Singapore’s response to successive waves of transmission during the COVID-19 pandemic.

DALMS, co-developed by Nm3 Tech and NEA, enables the collection of wastewater samples from manholes with depths greater than 20 metres, surpassing the 8-metre reach of existing commercial systems. This is particularly important for Singapore's extensive sewage networks.

“In a densely populated city like Singapore, environmental monitoring plays a crucial role in strengthening public health efforts. The Deep Autosampler Live Monitoring System (DALMS), designed to sample wastewater from depths exceeding 20 meters, played a key role in monitoring the spread of disease for informing national COVID-19 response. Ongoing innovations in wastewater surveillance will help Singapore better monitor infectious disease trends and build a more resilient city against bio-threats.”

- Dr Mark, Lei Lei, Director, Nm3 Tech (S) Pte Ltd & Dr Martin Tay, Senior Scientist, Environmental Health Institute, National Environment Agency

DALMS utilises innovatively designed pneumatic pumps to drive wastewater into an automated sampling system. This system enhances sampling safety by replacing traditional electrical pumps, which may pose explosion risks in manholes due to potential presence of flammable gaseous by-products from the sewage. It also allows more comprehensive wastewater surveillance by enabling sampling in previously inaccessible depths. Additionally, DALMS provides online notifications of failed sample collections, allowing corrective actions to be taken promptly to minimise wastewater surveillance disruptions. Notifications are made possible by a proprietary software that compiles, processes, and distributes data via mobile accessible platforms and online infrastructure for managing numerous wastewater samplers concurrently.

Singapore currently has an island-wide network of more than 500 wastewater samplers, including DALMS units from Nm3 Tech, among others. Beyond COVID-19, ongoing innovations in wastewater surveillance will help prepare Singapore to better monitor infectious disease trends, enabling a more resilient city against bio-threats.

The partnership between NEA and Nm3 Tech brought together various intangible assets, including engineering and microbiology know-how, fueling the innovation behind DALMS. The collaboration will in turn fuel more innovation and IP as use cases of wastewater sampling and surveillance are shared in the public domain, encouraging knowledge exchange with scientific and public health communities.

Actions on the ground

Here’s an example of the wastewater collection process:

1. Checks are conducted to ensure that the area is suitable for deployment.

2. The sampler is then set up beside the manhole, its tubing lowered and pumped into the manhole.

3. The manhole cover is then replaced with a customised cover that seals the manhole while still allowing access for sampler tubing to the sewage network.

4. The sampler is programmed to collect samples at specified volumes and intervals.

5. The sampler, comprising a control unit, a 24-bottle multiform base, connected to a battery pack and deep manhole pump controller system, is put together and placed in a weather-proof housing.

6. Samples of interest are collected and transferred to bottles which will be brought to the laboratory for testing. The sampler is decontaminated and ready for the next round of sampling.

Images courtesy of Nm3 Tech and NEA.