Plant Clonal Systems as a Strategy for Nitrate Pollution Removal in Cold Latitudes

Abstract

Nitrate removal is a major challenge in drinking water systems of major cities of the world and these are more acute in colder latitudes where metabolic conversion rates of biological species in the winter are slower. In order to achieve rapid nitrate removal we need multiple strategies including use of constructed wetlands in localized controlled greenhouse environments. In such localized controlled micro-environments higher temperatures can be managed for plant growth in hydroponics system through which nitrate contaminated water is fed for denitrification. Denitrification is a process that converts nitrate to gaseous nitrogen. This process is also referred to as “removal of nutrients”. The advantage of denitrification is that less oxygen is needed for the digestion of organic compounds in the aeration basin and specifically selected plants are needed for effective strategy. In the overall strategy to develop effective plant systems for controlled environment removal of nitrate pollution we have developed plant tissue culture technologies to isolate cold tolerant plant species that can be grown in aquatic and hydroponic environments. The use of innovative tissue culture technologies allows isolation of plant clonal lines of single seed phenotype origin that can be screened for cold tolerance and nitrate removal in aquatic zones. Such single seed plant clonal isolations are being evaluated for nitrate removal in the range of 25∼50 mg·L⁻¹ in hydroponic environments. The results of optimal removal of nitrate in greenhouse hydroponic studies will be presented. One group of plant species that hold promise for use in controlled greenhouse environments are species of aquatic mints. Strategy for specific clonal screening and use in cold latitude wetlands and greenhouse system for temperature control in the winter will be presented.