The scope of water quality monitoring is very wide, including regular surface and groundwater monitoring, monitoring of production and domestic processes, and emergency accident monitoring. Water quality monitoring can provide data and information for environmental management, and can provide a basis for evaluating the water quality of rivers and oceans. At present, the online water quality monitoring instruments developed and produced by JCDecaux mainly include: Internet of Things multi-parameter water quality online monitoring instrument, permanganate index online monitoring instrument, COD online monitoring instrument, ammonia nitrogen online monitoring instrument, total phosphorus automatic analyzer, total nitrogen automatic analyzer, integrated water quality micro-monitoring station.