CATCH BASIN CLEANING AT PLANTS 1 & 2 Wastewater treatment in Coos Bay uses a series of large concrete basins in which different stages of treatment is performed. Some basins allow for heavier solid waste to settle to the bottom with gravity, and some have air pumped to the bottom and dispersed through the liquid to oxygenate the hard-working beneficial bacteria (bugs). Each basin requires its own routine maintenance and the water quality team is responsible for entering the basin and cleaning the City’s asset. At Plant 1 on Ivy Street the aeration basin uses hundreds of cylindrical membranes to diffuse the air at the bottom of the basin. These membranes are also called socks. These socks have hundreds of slits in them to allow pressurized air to escape and infuse the water with oxygen that the bugs use as they eat the solids (aka poop) prior to the water being disinfected before exiting the plant. At Plant 2, on Fulton street, the membranes are disc shaped and the material has more smaller perforations that create finer bubbles in the water. Plant 2 has a large hatch in the side of the basin through which the water quality team can enter the basin once it is drained, to clean and perform maintenance on all equipment that is normally under water. Whether the aeration system is shaped like socks or like discs they all need scrubbed and inspected regularly because if even one fails it creates the path of least resistance for the air to rise to the surface instead of getting well dispersed air for the bugs. This process can take several days for each basin cleaning and the crews have worked hard this summer performing these maintenance activities.Photos from Coos Bay - City Government's post