The origin of black and stinky water "black" and "smelly":

Appropriate water temperature, slow water flow and rich nutrients are the distinctive features of urban rivers and lakes. The black odorous water body is the result of excessive soil pollution, resulting in ecological imbalance of water body and biochemical results in anoxic environment. The water body is under oxygen and even anaerobic conditions convert pollutants and produce odorous substances such as ammonia nitrogen, hydrogen sulfide, volatile organic acids and iron. Black substances such as manganese and sulfide. Domestic sewage is the most common and major source of pollution that causes black odor in urban rivers. Other sources of pollution include: domestic waste, industrial wastewater, overflowing pipe network overflow sewage, sewage plant tail water, rainfall and snow melt water, livestock and poultry farm waste water, plant and algae spoilage.

Black odor pollution main forming factor

The statistics of suspended matter input from nearly 90% of rivers captured by the coast and the carbon, nutrient salts and trace metals carried by the river show that the TOC (total organic carbon) and TN (total nitrogen) contained in the output water body The particulate content of TP (total phosphorus) and heavy metals is greater than that of the dissolved state.

The effect of the suspension factor is significant and should be taken seriously! !

Effect of dissolved air flotation treatment