Photo: Christchurch City CouncilA putrid stench lingering in Christchurch's eastern suburbs from the city's wastewater treatment plant is expected to persist for at least another week. Locals have complained of nausea and headaches and say the odour from the Bromley plant is driving them inside behind closed windows and doors. Christchurch City Council said recent heavy rain had affected the health of oxidation ponds and treatment plant staff were trying to improve the water quality. Photo: Christchurch City CouncilAnother Bromley woman, who did not wish to be named, said she was concerned about her health. Christchurch City Council head of three waters Gavin Hutchison said the council expected higher-than-normal odour levels to continue for at least another week.