Popular Disposal Options |
Fecal sludge from in-site sanitation |
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pit privy |
improved pit privy |
aqua privy |
compost toilet |
bucket latrine |
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high strengh |
low strengh |
sewage |
cost |
none |
1.5 times pit privy |
2 times pit privy |
2 times pit privy |
no construction cost, but operation may be costly depending on community |
example |
public toilet or bucket latrine sludge |
stepage |
tropical sewage |
design features |
pit, slab(squat or seat, lid, shelter |
same as pit privy + either pour-flush bowl, vent, pipe, off-set pit, or combination |
vault, slab (squat or seat), shelter, soak away |
double vault, 2 slabs (squat or seat), shelter |
platform, slab (squat or seat), bucket, shelter, large containers cart |
COD mg/l |
20 - 50000 |
< 15000 |
500 - 2500 |
construction skills |
minimal |
minimal |
some masonry |
some masonry |
minimal |
COD/DOB |
5:1 .... 10:1 |
5:1 .... 10:1 |
2:1 |
slab material |
bamboo, wood or concrete |
bamboo, wood, concrete,ceramic or plastic |
concrete |
concrete |
bamboo, wood or concrete |
NH4 - N mg/l |
2 - 5000 |
< 1000 |
30 - 70 |
water requirement |
no |
no except for pour-flush |
yes |
no |
not for operation, yes for washing trenches |
TS mg /l |
≥ 3.5% |
< 3% |
< 1% |
handling of waste |
none |
none |
every 2-6 year as sludge |
every 6-12 months as compost |
every 1-3 days as excreta |
SS mg/l |
≥ 30000 |
7000 |
200 - 700 |
maintenance |
clean slab weekly, dig new pit and move slab & shel-ter each 4 - 6 years |
same as pit privy, if off-set pit, clean chute, weekly and dig new pit every 10 or more years |
- maintain water level in vault - clean slab weekly, dig new pit every 10 or more years |
- clean slab weekly - alternate use of vaults every 6 - 12 months by removing compost, clean one vault, seal the other |
- clean slab weekly, remove excreta every 1 - 3 days; clean buckets every 1 - 3 days - cart excreta to trenching ground & bury it or to composting area |
helminths eggs number / l |
20 - 60000 |
4000 |
300 - 2000 |
Suggested effluent and biosolids quality guidelines for the treatment of faecal sludges |
Impact of Sanitation |
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A. Liquid Effluent |
BOD (mg/l) total |
BOD (mg/l) filtered |
NH4-N (mg/l) |
Helminth eggs (n°/L) |
FC (n°/100mL) |
Categoy |
impact |
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1. discharge into receiving waters |
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I : Faecal-oral, non bacterial |
negligible |
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seasonal stream or estuary |
100 - 200 |
30 - 60 |
10 - 30 |
≤ 2 - 5 |
≤ 10 |
II. Faecal-oral bacterial |
weak to moderate |
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perenial river or sea |
200 - 300 |
60 - 90 |
20 - 50 |
≤ 10 |
≤ 10 |
III. Soil-borne helminths |
strong |
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2. Reuse |
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IV. Cow and pig parasites |
strong |
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restricted irrigation |
not critical |
not critical |
crop nitrogen requirement 100-200kgN/ ha.year |
≤ 1 |
≤ 10 |
V. Water-born helminths |
moderate |
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unrestricted irrigation |
not critical |
not critical |
crop nitrogen requirement 100-200kgN/ ha.year |
≤ 1 |
≤10 |
VI. Vectors (insects) |
weak to moderate |
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B. Treated plant sludge |
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use in agriculture |
not critical |
not critical |
not critical |
≤ 3 - 8/ g TS |
safe level if egg standard is met |
nfm: not from me, various |
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