Ozonering av organiska mikroföroreningar på Ryaverket : Förbehandlingens påverkan på ozondosen och interaktion med den befintliga processen

Sammanfattning

Wastewater treatment plants are one of the main pathways of micropollutants contaminationfrom humans to water recipients. The new EU wastewater directive, which was updated inNovember of 2024, makes demands on reducing 80% of micropollutants at wastewatertreatment plants. This master thesis investigates which ozone doses are required for ozonationto reduce organic micropollutants at Ryaverket in Gothenburg. Two ozonation experiments were conducted at laboratory scale with three water matrices fromRyaverket: effluent water from the treatment plant, effluent water from the post-sedimentationand frozen saved samples from an AGS-pilotplant. Doses between 0 and 1.0 mgO3/mgDOCwere tested and analysis was conducted for 39 organic micropollutants and for standardwastewater parameters. Results show that all analyzed micropollutants, except for PFAS-substances, were reducedduring ozonation. For 80% reduction doses between 0.2 and 0.45 mgO3/mgDOC were required.Nitrite had a large effect on the ozone demand and nitrite concentration of 0,5 mg/L increasedthe ozonedose by 30%. Bromate formation occurred during the ozonation and reached aconcentration of about 20 µg/L at an ozone dose of 0.8 mgO3/mgDOC.