Dear Jacky,

Thank you very for your valuable comments for which our response is as follows:

Jacky Foo [foo@SWIPNET.SE] wrote:
>In the Guidebook on biogas development (ESCAP, 1980), in calculating the
>number of persons needed to provide human sewage to a digester, the
>following data (probably Chinese) is used :
>1 adult can provide 200 gm (200 ml) night soil
>800 ml urine
>and
>1000 ml of flush water.
>i.e. 2 litres per person of influent into the digester.
>
>In your calculations used for your paper, you have an average of 285
>visitors per day to the community latrine and based on 400 gm of faeces per
>person.
>Q: is 400 gm an estimate or an experimental average ?
>Q: what is the total estimated influent volume per day into the digester ?
>(i.e. including flush water, etc)

Based upon literature review and interpolated/stimated calculation, we have used the following assumption to calculate the volume
of excreta available in the context of Bhutanese Refugee camps in Nepal.

Age Group                       Excreta production/day

Adult (15 years or above)               400 gm
10 to 15 years                              300 gm
6 to 10 years                               200 gm

To control the volume of water, it was suggested to use 0.5 litre of water per person for anal cleaning.

>I would suspect that a community-latrine as described in your paper would
>have more users to the urinals.
>Q: was a survey conducted to find out how many visitors use the urinal or
>toilet ?

Yes, as there is no charge for urination, there are more latrine visitors to the urinals compared to defecation (One Rupee is charged for defecation/person).

Yes, at later stage when the number of latrine visitors are stabilized, the survey of latrine visitors was done in course of monitoring activities of the community latrine-cum-biodigester.

>In Diagram 4, the flow chart from the biodigester indicates the use of the
>biogas and the sludge. There is no indication for the flow of the liquid
>portion of the digested slurry.
>
>Q: what is the fate of this liquid  ?

The flow chart of the liquid portion (i.e. digested faecal sludge) of the biodigester has been indicated under the concept of the production of biogas and stabilized compost ...(see Figure in the text)...The semi-liquid sludge is directly led into the compost pit for decomposition and drying in conjunction with vegetable residues such as rice straw, plant leaves etc.

The liquid contained in the digested feacal sludge is absorbed by the plant materials used for composting. This  facilitates the easy handling of composted manure.

We look forward to receiving more and more comments from you.

Best regards and wishes for the success of the conference.

Amrit and Upendra