Problem: During the colder winter months, the flow to the facility increases due to seasonal tourism. The operator finds that maintaining effective coliform kills is more difficult during this time even though the chlorine residual is above the minimum requirements and the effluent appears clear with low turbidity. What could be done to improve the disinfection? O Add soluble iron salts to remove any sulfide O Add sulfur dioxide at the chlorine injection point Place an additional chlorine contact tank on-line O Raise the effluent pH using caustic soda