Data presented in Table 1 show that the biogas production in batch digester starts from 2^nd day but its amount was quite low as 26.2mL only which suddenly jumped to 235.8 mL on 4^th day and thereafter it remained between 235.8 and 262.0mL from 4^th to 6^th day. From 7^th to 10^th day biogas production further increased and remained between 432.3 and 524.0mL. From 11^th to 24^th day biogas production varies between a minimum value of 602.6 mL and a maximum value of 681.2mL except 12^th day (550.0mL) and 16^th day (563.3mL). This is the period in batch digester when highest biogas production was obtained. From 25^th day onwards biogas production decreases continuously. It ranged between 510.9 to 576.4mL between 25^th and 31^st day, except 29^th day (495.0mL); 406.1 and 497.8mL between 32^nd and 50^th day, except 36^th day (537.1mL), 37^th day (510.90mL) and 40^th day (524.0mL); 327.5 and 366.8mL between 51th and 67^th day, except 53th day (419.2mL); and 235.8 and 288.2mL between 68^th and 80^th day, except 78^th day (91.7mL). Data show that after 80^th day biogas production in batch digester remains below 100 mL and decreases continuously till 99 days and reaches to a minimum value of 13.1mL. Data of biogas production in batch digester show that there is continuous increase in biogas production till a peak is reached and then it decreases continuously, due to reduction of nutrients in digester may produce starvation condition therefor methenogesis process undergoes decrease.  Similar trend was observed previously².

Table (1):
Daily production of biogas in continuous and batch digester throughout the experimentation period.

This trend did not observe for biogas production in continuous digester. Here, biogas production ranged between 406.1 and 432.3mL from 1^st to 10^th day, except on 4^th day (393.0mL). It should be noted here that 1^st day of continuous digester refers to the day after it is being filled at 4800mL (actual 41^st day of experimentation and so on). Thereafter between 11^th to 62^th day biogas production decreases and ranged between 301.3 and 393.0mL, except on 15^th day (248.9mL), 21^st, 23^rd and 30^th day (406.1mL) and 58^th day (280.34mL). From 63 to 66^th day, biogas production further increased and ranged between 406.1 and 410.1mL. From 67^th day biogas production further decreases and ranged between 340.6 and 393.0mL between 67^th and 82^nd day except 71th day (419.2mL) and 75 and 76^th day (406.10mL). From 83^rd day onwards biogas production again increases and ranged between 406.1 and 471.6mL between 83rd and 99th day, except 85th day (393.0mL). With respect to batch digestion continuous digestion system getting nutrients on daily basis therefor methanogenesis process didn’t disturbed and biogas production remain near to constant rate.  Similar trend was observed previously in a continues anaerobic digestion study³.

Total biogas production during the experimentation period of 99 days was recorded as 37833.94mL in continuous digester with average of 382.16mL per day and as 31955.1mL in batch digester with and an average of 322.78mL per day.

A close observation of Data presented in Table-1 reveals that the biogas production was higher in batch digester compared to continuous digester from Day 7^th to 56^th (Fig.1). Whereas, from 57^th day to 99th day reverse trend was observed and biogas production shows its higher value in continuous digester compared to batch one (Fig. 2). Effectiveness of batch digestion process over continues digestion process in earlier stage of digestion was reported³ using Mathematical Models for Comparative Evaluation of Batch and Continuous Anaerobic Digesters.

Biogas production and Temperature
Data presented in Fig. 3 reveals that biogas production in batch digester has no relation with increase or decrease in average temperature value. Results conclude that the biogas production is affected by some other factors than temperature.

On the other hand, production of biogas in continuous digester follows the path of rise and fall in average temperature (Fig. 4).

Comparison of produced biogas in continuous and batch digestion clearly reveals that in continuous digester a steady amount of biogas is generated (minimum 248.9mL and maximum 471.6mL) whereas in batch digester production of biogas varies greatly (minimum 26.2 and maximum 681.20mL) and gives Bell shape curve (Fig. 5). In batch digester a sharp increase in biogas production is recorded from 6^th to 7^th day and between 9^th and 11^th day and thereafter from 80^th day the biogas production continuously decreased. High temperature favours the biogas production⁴and it decreases at low temperature.

Table (2):
Methane content in biogas produced in continuous and batch digestion process (%).

Amount of produced biogas is not much important as its methane content because it is the utilizable part of biogas. Data presented in Table-2 reveals that produced biogas in continuous and batch digestion process contains more or less similar amount of methane in it. So in this aspect there is no difference between these two processes.  Initially lower methane content in batch digestion than continues digestion and then with time it goes more or less similar in both were also reported⁵.