DirectINJECT: Dosing Systems for Concentrated Liquid Biocides

Date

7/10/2022

Journal Title

Journal ISSN

Volume Title

Publisher

51st International Conference on Environmental Systems

Abstract

Reliable and mass-efficient techniques for biocide dosing are necessary to enable residual microbial control in spacecraft potable water systems. DirectINJECT is an approach to provide ultra-low flow rate injection of stable aqueous biocide concentrate solution (e.g., highly soluble silver salt). This method has the benefit of low consumable mass and is insensitive to the chemistry of the target water. With a 40 g Ag+/liter solution, required dosing rates would be ~1 ?l/minute during water processing (for a system similar to the ISS WPA), requiring only approximately 20 ml/crew-year of concentrate. The performance of three dosing systems were identified and characterized: pressure-driven flow through a robust micro-capillary tube with a solenoid valve shut-off, a miniature peristaltic pump, and a multi-piston pump with integrated valving. Several potential system performance and reliability concerns are addressed including prevention or segregation of gas bubbles in the concentrate reservoirs as well as long-term materials compatibility, leak minimization at valves and seals, and mechanical life.

Description

John Vance, NASA AMES RESEARCH CENTER / KBRwyle, US
Lance Delzeit, NASA, US
ICES303: Physio-Chemical Life Support- Water Recovery & Management Systems- Technology and Process Development
The 51st International Conference on Environmental Systems was held in Saint Paul, Minnesota, US, on 10 July 2022 through 14 July 2022.

Keywords

silver, silver ion, biocide, concentration, potable water, dosing, metering, injection, pumping, reservoir, storage, microfluidic

Citation