Improving Sanitation - Creating Compost Soil

In 2014, The Imani Project, with the assistance and support of Chantal’s Little Shoes, will open its first community composting toilet. The construction of the four-stall structure in Mashaheni Village was completed in early January. 

Composting
The Imani Project Community Composting Toilet

The next step is to train the villagers how to use the facility to properly use the toilet and create compost. In February, the Imani Project started the education process.  Success of the facility depends on everyone following the proper procedures when making a deposit and the daily task of putting the solid waste into the compost pit. 

The facility will be fully operational starting in the spring of 2014.  The first batch of nutrient rich compost should be ready by the end of 2014.

Why Build Composting Toilets?  To Bring a BETTER LIFE

Composting toilets improve sanitation and reduce disease by controlling the disposal of waste liquid and solids. They also require little water to operate, and water is a precious resource in Kenya villages. In addition to preventing disease, composting toilets provide:

  • Production of rich compost soil fertilizer
  • Production of liquid fertilizer from urine collection
  • Increased garden yields

How Does the Composting Toilet Work?

Click photos to see larger images.

Squat Plate
Squat Plate

The composting toilet, also known as a urine-diverting toilet, is designed to collect urine and feces separately.  The liquid and solid wastes are treated independently, each becoming a source of different fertilizer. The toilet uses a special "squat plate" with separate holes for collecting urine and feces. 

The urine hole connects to a sealed tank where the liquid waste is stored for later use. The tank must be fitted with a tight cover to prevent oxygen from turning the urine's nitrogen into ammonia, which smells bad and causes some nitrogen loss. 

Feces Collection Bucket
Feces Collection Bucket

The feces (without urine) falls directly into a bucket below the stall. Humus or leaves are used in the base of the bucket when it is empty to avoid sticking, and soil or wood ash are added to the bucket after every deposit is made.  This additional material helps in handling the waste and with the composting process. Toilet paper cannot go into the bucket; it must be collected and burned separately. The buckets are accessed by the red doors near the ground on the back wall of the toilet

Composting Pits
Composting Pits

The buckets are emptied every day into pits behind the toilet for full decomposition and eventually turning into compost. The material will be left in isolation, without contact from people, until it is fully composted and safe to handle. Bacteria and dangerous organisms are killed by a variety of processes, including heat and predation by other micro-organisms. The rate of decomposition is a combination of temperature and time: the hotter the compost pile, the more quickly the process happens.  In a hot climate like Kenya, it can take between 6-9 months. 

Using the Liquid Fertilizer

Liquid fertilizer from urine is rich in nitrogen, phosphorus and potassium, the major components of commercial chemical fertilizers. Urine is typically sterile when separated from feces, and it can be easily and safely reused.  

Urine must be diluted before use: one part urine to three to six parts water.  The liquid is then poured into the soil around plants, but not on young seedlings. To flush salts in the urine from the soil, the gardner will alternate urine with water or apply the urine before a rain.  Urine can also be composted by pouring it onto sawdust, leaves, or other carbon-rich materials and letting it process.

Using the Solid Fertilizer

Corn Example
Corn Example

When fully composted, toilet compost, or “humanure” is pleasant to handle, safe to use, and has no smell. It can be used as a potting soil or added to vegetable and flower beds. Humanure can dramatically enhance the poor, sandy soil that is common in Africa. Vegetable production can be improved significantly with the use of humanure. 

Toilet compost varies a great deal in texture and color depending on the amount and type of soil added. Adding fertile soil and leaves produce a humus-like compost. Adding sandysoil produces a sandy, almost humus-free compost. 

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