Blackwater is cheaper and easier to process than greywater.

The question seems to be incomplete, but both types of water are involved in the sewage systems in society. 

Blackwater is basically wastewater that contains materials flushed from toilets (e.g. feces, urine). Greywater on the other hand, is also known as sullage. They are wastewater that people generate from sources that are not coming from toilets (e.g. food washing, dishwashing, bathing, clothes washing). 

D.na is the answer hope this

Order of filling levels and sublevels of electrons: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²3f¹⁴5d¹⁰6p⁶for an element with 5 electrons in the 3d energy level: full configuration: 1s²2s²2p⁶3s²3p³.