I saw one reference to using lime, you can also use lye or woodash to mitigate the smell as well as make some attempt to disinfect fecal material. One of the big dangers of longterm failure of a sewage system is the inevitable outbreaks of dysentery and cholera.
For the unitiated, those are more graphically known as terminal diarrhea. It comes from contact with infected fecal material.
I think as soon as practicable, one should consider relocation to a less densely populated area. Humans are terrible disease vectors, especially after an infrastructure breakdown that would limit or eliminate any manner of sanitation as well as reliable drug therapies.
Folks with TB who haven't taken their entire antibiotic regime as well as other folks with untreated infectious diseases, are going to be distributing their infected sputum, feces, and other bodily fluids indescriminately. If you don't have sewer, chances are the water supply is suspect if at all operational. Time to get out of dodge unless you are completely self-contained and quarantined from outside contact.
These are always public health concerns in areas disrupted by war, natural disasters and other infrastructure breakdowns.