Sharing the Secret: Mobile Soak Pits Improve Safety, Efficiency in IRS

journal of en management

The PMI AIRS Project recently published in the peer-reviewed Journal of Environmental Management on the benefits of mobile soak pits – an innovation developed by the project. Mobile soak pits improve spray team mobility, productivity and safety of PMI malaria control programs. Read the article here.

End-of-day clean-up operations require the safe disposal of wash water resulting from washing the exterior of spray tanks and spray operators’ personal protective equipment. Indoor residual spraying (IRS) programs typically use soak pits – large, in-ground filters – to adsorb, filter and then safely degrade the traces of insecticide found in the wash water. Usually these soak pits are permanent installations serving 30 or more operators, located in a central area that is accessible to multiple spray teams at the end of their workday. However, in remote areas, it is often impractical for teams to return to a central soak pit location for cleanup.

To increase operational efficiency and improve environmental compliance, the PMI AIRS Project developed and tested mobile soak pits (MSP) in the laboratory and in field applications in Madagascar, Mali, Senegal, and Ethiopia where the distance between villages can be substantial and the road conditions poor. A 20-quart container with layers of stone, activated carbon, and sawdust, MSPs can be installed almost anywhere a spray team completes their daily operations. Since the mobile soak pit weighs about 15 kilos, it can be carried to a spray location, installed at a wash site in minutes, and used to catch and treat insecticide waste. After cleanup, the mobile soak pit and tarp for the wash area are removed, and the hole for the soak pit is refilled. The mobile soak pit is then dug up and carried away for use at the next location, while the site is restored to its original condition. As a result, spray operations leave as close to a zero environmental footprint as possible in spray areas.

Laboratory testing confirmed the ability of the easily-assembled MSP to reduce effluent concentrations of two insecticides (Actellic 300-CS and Ficam VC) used by the PMI AIRS Project, and to generate the minimal practicable environmental “footprint” in these remote areas. Field testing in the Mali 2014 IRS campaign demonstrated ease of installation and use, resulted in improved and more consistent standards of clean-up, decreased transportation requirements, improved spray team working conditions, and reduced potential for operator exposure to insecticide.