Journal of Environmental Treatment Techniques  
2020, Volume 8, Issue 2, Pages: 794-796  
J. Environ. Treat. Tech.  
ISSN: 2309-1185  
Journal web link:  
Biogas Generation from Rice Cooking Wastewater  
Nadim Reza Khandaker*, S M Shabab Islam, Umme Farah Shakin  
Department of Civil and Environmental Engineering, North South University, Dhaka, Bangladesh  
Received: 13/08/2019  
Accepted: 16/04/2020  
Published: 20/05/2020  
Rice is the staple of all families of South Asia and South East Asia. The process of cooking rice involves boiling the rice in water which  
leaves a byproduct of decanted liquid. The research showed that the wastewater generated from cooked rice could be used to generate biogas  
with a biogas generation potential of 190 ± 46 mL/g BOD (5.38 ± 0.75 L of biogas/per L of Maar) with the methane content of 78 %. First  
order reaction defines the kinetics of biogas production with the intent of fitting between modelled and observed data (r ) of 0.961. The first  
order kinetics constant “k” was determined to be 0.2 d . Further a family of four produces 1.0 L of starch rich wastewater per day that has  
the potential to produce 5.38 L of biogas with 78 % methane content. Further a household reactor was built out of recycled plastic chemical  
drum seeded with cow dung fed with waste rice cooking wastewater handling the wastewater decanted from the daily rice cooking for a  
family of five. The biogas generated was used as demonstration to fire a biogas household burner. The experimental program shows the  
potential for the use of starch rich wastewater in an urban setting to augment the energy needs for cooking.  
Keywords: Biogas generation potential, Cooked rice decant wastewater, Kinetics  
The overall intention of the experimental program was to  
introduce domestic rice wastewater in the energy diversification  
to stride for sustainable development of South Asian and East  
Asian countries future and to identify a source which is readily  
available can produce a positive sustainable solution at the  
household level.  
Bangladesh is a country whose economy is natural gas driven.  
Natural gas is used for electricity generation, fertilizer production,  
process heating, electricity generation, and household cooking.  
About 70% of Bangladesh’s energy demand is met through  
natural gas but in recent times, the demand of natural gas has been  
exceeding the supply (1). The government has started to put in  
place measurers that limit supply. Natural gas supply has been  
limited for domestic use placing an undue burden to the urban  
population. However, amidst all the crisis, we may have found a  
simple potential solution from a very unlikely source in the form  
of wastewater generated from rice cooking that serves as the  
substrate for biological methane generation. Rice is a staple food  
in Bangladeshi households. People rely on it as the chief source  
of their dietary needs at least twice per day. The process of  
preparing rice involves boiling it in water and this process gives  
off a white starchy liquid which is referred to as “Bhaather Maar”,  
and in this study this rice rich wastewater was used to conduct a  
Biological Methane Potential (BMP) study (2) to ascertain how  
much biogas can be produced from waste water generated from  
rice cooking. In a controlled experimental program wastewater  
generated from cooking rice was characterized, using methane  
generating reactors at the bench scale a BMP study was conducted  
to ascertain the quantity and quality of the biogas generated from  
Maar. The study was further expanded to actual application where  
a waste acetone empty plastic drum was converted to a biogas  
generator and installed in a urban house as a field trial. The  
generated biogas was used to fire a household level cooking  
burner to demonstrate the practical efficacy of using waste cooked  
rice water to produce biogas for domestic use.  
2 Materials and Methods  
Raw wastewater: The rice cooking wastewater was obtained  
from actual wastewater generated from cooking rice in a typical  
household of urban Bangladesh, in average 1.0 L of rice  
wastewater is generated per day from a family of 4 persons. A  
seven-day composite sample was used to characterize the  
wastewater used in the study.  
Seed: The BMP study seed was seven-day old crow dung  
and for the pilot reactor the seed source was fresh cow dung.  
Analysis: The rice cooking wastewater was analyzed for  
COD, BOD , TS, and pH as per standard methods (4). The biogas  
generated was measured using the piston displacement method  
where the piston in the syringe reactor moves up with daily biogas  
production the displacement volume is noted by reading off the  
gradation lines existing in the syringes used as the BMP reactors  
BMP Reactor Configuration: The bench scale BMP reactor  
were 150 ml plastic disposable syringes with a liquid volume of  
20 ml (Figure 1). The BMP syringe reactors were operated as  
batch rector with an incubation period of 34 days. In the BMP  
study the rice wastewater was fed directly to the reactor at the  
initiation of the study. The food to microorganism ratio (F/M) for  
the BMP study was 0.02. The daily biogas production was  
Corresponding author: Nadim Reza Khandaker, Department of Civil and Environmental Engineering, North South University, Dhaka,  
Bangladesh. E-mail: