Dear Jacky,

Please excuse us for replying your email dated 12 April so late. Also based upon our previous emails, we would like to edit the text by incorporating quantitative data as follows:

a. Waste Water Flows

The anaerobic digestion of the latrine waste will yield semi-liquid byproduct-both solid and liquid effluents (also called biogas slurry). The solid portion will be absorbed by the plant residue (see b below), leaving behind liquid as waste water. When the slurry is led to the compost pit, excess amount of liquid can produce water-logging condition as you have rightly pointed out. Therefore, to drain out the liquid portion (waste water), an under-ground temporary waste water collection tank was constructed. The quantity of waste water produced is calculated to be around 115 litre per day.

b. Solid Flows

The daily output of the digested faecal material (solid) is expected to be about 50 kg/day. With the daily addition of 400 kg. of dried vegetable materials, about 100 metric tons of the matured compost is expected to be produced per annum for use  as organic fertilizer.

c. Pathogen Flows

It has been reported that in the process of anaerobic digestion of human waste, about 95% of the pathogenic germs are killed due to which the incidence of the contagious diseases is greatly reduced.

As the plant is located in high water area, it was felt that perhaps the underground water would be contaminated by the pathogens in case they are completely destroyed. Therefore, for water testing against the pathogens, two observation wells were erected to draw the water sample for testing. Result of analysis of water test of the bacteriology for ova, cysts, parasites and coliforms carried out about two years ago revealed following results:

No ova, cyst and parasites seen. (In Nepal, Ascaris (Round worms)is very common. Therefore, the major parasites detected were: Roundworm, hookworm, threadworms,etc.)
. 2 to 7 E. coli/100 ml.
. Test categorized as : "B".
. The tested water is acceptable for drinking because of the closing of the
project, the test was not repeated in the subsequent years.

d. Nutrient Flows

Good quality of compost can be made by treating the organic waste of human and animal original. Such compost which is very rich in plant nutrient contents (Organic matter, N,P, K and micro-nutrient)  has immense value for the farmers became they have to be not only dependant upon the imported and costly mineral fertilizer but also they obtain valuable bio-fertilizer on time locally.

Though it was envisioned to conduct chemical analysis of the digested sludge (e.g. organic matter, Nitrogen/Ammonium, Phosphorus, Potash, micro-elements needed for plant nutrient), because of the expiry of the project such tests are still overdue.

Best regards,

Amrit & Upendra