without ever storing it. Called "flow-through" facilities, they use fine screens to remove solids and sanitary trash from the combined sewage. Flows are injected with sodium hypochlorite for disinfection and mixed as they travel through a series of fine screens to remove debris. The fine screens have openings that range in size from 4 to 6 mm, or a little less than a quarter inch. The flow is sent through the facility at a rate that provides enough time for the sodium hypochlorite to kill bacteria. All of the materials removed by the screens are then sent to the sewage treatment plant through the interceptor sewer. Reducing stormwater flows Communities may implement low impact development techniques to reduce flows of stormwater into the collection system. This includes: constructing new and renovated streets, parking lots and sidewalks with interlocking stones, permeable paving and pervious concrete installing green roofs on buildings installing bioretention systems, also called rain gardens, in landscaped areas installing rainwater harvesting equipment to collect runoff from building roofs during wet weather for irrigating landscapes and gardens during dry weather implementing graywater collection and use on site to reduce sewage discharges at all times Green infrastructure CSO mitigating initiatives that are solely composed of sewer system reconstruction are referred to as gray infrastructure, while techniques like permeable pavement and rainwater harvesting are referred to as green infrastructure. Conflict often occurs between a municipality's sewage authority and its environmentally active organizations between gray and green infrastructural plans. The 2004 EPA Report to Congress on CSO's provides a review of available technologies to mitigate CSO impacts. Real-time decision support systems Recent technological advances in sensing and control have enabled the implementation of real-time decision support systems (RT-DSS) for CSO mitigation. Through the use of internet of things technology and cloud computing, CSO events can now be mitigated by dynamically adjusting setpoints for movable gates, pump stations, and other actuated assets in sewers and storm water management systems. Similar technology, called adaptive traffic control is used to control the flow of vehicles through traffic lights. RT-DSS systems take advantage of storm temporal and spatial variability as well as varying concentration times due to diverse land uses across the sewershed to coordinate and optimize control assets. By maximizing storage and conveyance RT-DSS are able to minimize overflows using existing infrastructure. Successful implementations of RT-DSS have been carried out throughout the United States and Europe.