Toilet

Bowl type

  • Squatting pan
  • Western seat
  • Chamber pot, baby potty, “bed pan”

Squatting is more ergonomic and healthy.

Waterless urinals.
Some have lighter than water sealant floats in the U bend.
Others have rubber valves.

Anal cleaning

  • Water
  • corn cob
  • toilet paper.
  • leaves
  • sticks

Connection mode

Water seal

Blocks smell, flies etc..

Dry toilet

Urine and water are (mostly) diverted to a separate hole.
There may be a separate hole for washing anus.
Post defecation, dry matter is ideally thrown in to cover the feces.
Feces is kept as dry as possible - to prevent flies and odor.

Waste collection

Bucket toilet

Aka pail closet, pail privy.
Bucket under the bowl is periodically emptied.
Bucket is lined with newspaper, dry leaves, sawdust, sand etc.. for easy emptying.
The receptacle should be in a closed container - to avoid flies.

2 bucket system - one for feces, another for urine.

Container toilet - Like a bucket toilet - except it’s sealed before collection.

Composting toilet

Instead of the bucket there may be a composting chamber, with ventilation pipe - for mostly aerobic degradation.
Can accept limited urine - else better to divert to avoid anaerobic conditions.

Moist carbon material must be hadded.

Pathogen destruction rates in composting toilets are usually low, particularly of helminth eggs.

Plastic toilet booths

  • Uses chemicals to minimize smell.
  • Tank’s often emptied to sewer.
  • Often include ventilation pipe leading to the roof, with insect screen (wouldn’t work well if door is open to wind).

Pit latrine

Hole over a pit.

Shelter

Often has a shelter - aka outhouse for protection from weather.

No-roof - more light, ventilation, disinfection via solar radiation, less weight. But top should be raised to prevent rain runoff and overflowing.

Hole

The hole may be in a slab or between stones.
If hole is bigger than the recommended 25cm/ 10 in - Risk of kids falling in.
Hole may be closed with a lid if inside a shed, to prevent flies. Eg. kaDaba village in 1990s

Pit

Pit may be partially lined at the top to prevent collapse - eg. during emptying.
Circular pit is less likely to collapse.

The pit may have a ventilation pipe (with a fly screen) going to the roof.
Twin pits with pipe sealing may be used.

Depth

Pit should be at least 2 metres (6 feet) above groundwater level.
Arborloo pits are shallow - but there is a slab on top - good for planting trees later.
In old confrederate states, pits were made to be 6 feet from the ground to prevent hookworms etc..

Location

Drinking water wells should be far away laterally (how far depends on soil conditions).
Most, but not all pathogens die within 50 days of travel through the subsurface.

When pit fills up, the latrine should be moved or emptied.
If latrine is moved, a fruit tree can be planted (arborloo technique)

Cess-pits

  • Aka cess-pit, cess pool, soak-pit
  • Pipes brings feces etc.. in.
  • Lined with stones etc.. Still risk of cave-ins.

Cleaning

  • Used to be cleared at night. Risky for cleaners.
  • With pumps for the liquid, then shovels

Septic tank

  • inlet → sedimentation of sludge, floating scum, anaerobic decomposition → draining.
  • pathogens are usually reduced due to heat, soil absorption
  • periodic desludging needed.
  • Handles grey-water too.
  • widely used in EU and US. Earlier many drained to watercourses.
  • Basic designs - Can fill up fast, become smelly.

Toilet bags

  • plastic
  • biodegradable

Feces cover material

  • Purposes
    • keeps feces dry
    • avoid odor
    • adds carbon to balance out nitrogen for composting
    • raises pH, bad for pathogens
  • powdered lime, sand, rice hulls, soil, wood ash etc.. are added before and after use to avoid smell, flies, etc..
  • “Earth closet” was used to flush such material over feces.

Dry feces collection

With urine-diverting dry toilet (UDDT), separate from urine diverting compost toilets.
There may be two vaults/ bowls; or a single vault may have a changeable container.

The feces is stored dry for 6+ months after last feces is added. Then dehydration occurs beyond pathogen tolerance, pathogens decline.
The water content of dried feces after six months of drying is usually less than 25%.

  • Often include ventilation pipe leading to the roof, with insect screen.

Less odor compared to wet feces + urine collection. Safer to handle.

Waste disposal

Fresh feces consist of about 80% water.

Feces

Pathogens

High temperatures or long composting times are required to kill helminth eggs, the hardiest of all pathogens.

Fertilizer

Good for fruit trees - not vegetables due to disease risk.
Dry fertilizer is better.

Nutrients

Urine is high in nitrogen, phosphorus, potassium and important micro-nutrients.
Can help offset “peak phosphorus” crisis. phosphate in urine could supply 22% of the total demand. Might need to be balanced with carbon.

Open defecation

If in high concentration, can lead to disease spread. Otherwise ok.
Human faeces normally take about a year to biodegrade outdoors.
Emptying unaged feces from bucket toilets etc..
is mostly as good/bad as open defectation.

Tree bog

Raised platform for shitting in compost pile among nutrient hungry vegetation (eg. willow trees, mint). Seating platform is atleast 1m high.
Feces is well ventilated for aerobic decomposition.
Carbon rich material is used to cover feces - to balance urine nitrogen.
Weed nettles soon grow if allowed.

Burial

Can dig a “cat”-hole, cover with soil.

Can work with feces from bucket toilet, dry feces etc.. Minimum depth - 25 cm.

City sewage treatment

Toilets connected to city sewage system are easy to build and maintain.

Typical systems:

  • toilet bowl → pipe with chambers inbetween → town sewage pipe with manholes! → sewage treatment plant (hopefully)
    Chambers are necessary for inspection and maintenance.
    • Pipes
      • Concrete pipes tend to degrade, be susceptible to roots, rats and cave-ins. PVC pipes are better.
  • Exposed gutters.
  • Workers collect waste from cess-pits and buckets (eg. via special “conservancy” lanes + special bucket doors); and then dispose.

Ultimate disposal

  • Incineration.
  • Fertilization

Urine

Urine is usually close to sterile.
Can be diluted with water and used for agriculture.

Or can be infiltrated into soil via - soak pit, gentle slope etc..

Residual pathogen removal - storage in closed vessels (five weeks at temperatures below 20 °C or of two weeks at temperatures above 20 °C).
The decomposition of urea that is present in urine into ammonia and hydrocarbonate leads to an increase in ammonia concentration and an increase of pH value to above 9.

Grey water

aka sullage.
Grey water = All streams except for the wastewater from toilets.

Constructed wetlands

Can be let into a constructed wetland/ reed beds/ soil infiltration beds.
Plants such as water hyacinth (Eichhornia crassipes) and Pontederia spp. are used.
Can be surface-flow or subsurface-flow or hybrid.
Look like ponds.

Might encourage musquito, have odors, algae.
Can add fish to combat those.