Hydroxide stabilization as a new tool for ballast disinfection: efficacy of treatment on zooplankton

Toxicity of Aqueous Alkaline Solutions to New Zealand Mudsnails, Asian Clams, and Quagga Mussels

“…Because of the simplicity of elevating water-system pH with NaOH, its potential use in confined pipes and in channels and tanks infested with nuisance mollusks may hold promise. Tests of ballast disinfection using additions of NaOH (Elskus et al 2015;Moffitt 2015a;Starliper et al 2015) suggested that not only was this chemical effective, but that after neutralization with CO 2 , the effluents would meet regulatory guidelines for safe discharge. Sodium hydroxide was registered as a herbicide many decades ago for control of tree roots in sewer systems, as a fungicide and algicide for use on water-well casings, and as a disinfectant in various indoor settings (USEPA 1992).…”

“…Elevating the pH of water with NaOH in freshwater ballast systems has been reported as highly effective to kill a suite of plankton and bacterial or viral species (Moffitt et al 2015a;Starliper et al 2015). The alkaline solutions in ballast tanks used can be neutralized with CO 2 , yielding environmentally harmless compounds that have been shown to meet effluent guidelines (Elskus et al 2015;Moffitt et al 2015a). The pH of freshwater can also be elevated easily with addition of Ca(OH) 2 (Moffitt et al 2015b), but with testing Ca(OH) 2 has proved difficult because of the lowered solubility of this compound.…”