| The discovery came about during rescue excavations on Thames Water's sludge works. |
| To feed the microbes, plants must aerate sewage sludge with costly, power-hogging equipment. |
| The most common is activated sludge, a process in which microbes, also known as biomass, are allowed to feed on organic matter in the wastewater. |
| Many areas have no waste water treatment plants at all, with sludge and sewage disposal going directly in to the ocean. |
| The sludge generated from backwashing the filters is sent to a spent washwater tank for recirculation through the facility to minimize waste. |
| They may not break down readily and will contribute to the scum or sludge layers. |
