Characterization of rice straw as substrate for biomethanation / Luis Z. Avila.

Thesis (M.S. - - Agricultural Chemistry) University of the Philippines, College, Laguna.

Includes bibliographical references.

AVILA, LUIS ZULUETA, University of the Philippines at Los Banos, Jumz 1983, Characterization of Rice Straw as Substrate for Biomethazation. Major Professor: Dr, William G, Padolina

The different treatments examined exhibited varying degrees of effect on the six different components of rice straw, The different treatments examined include chemical treatments using sodium hydroxide, ammonia, sodium hydroxide with neutralization using hydrochloric acid, potassium periodate , potassium permanganate, calcium hydroxide # sodium carbonate, sulfur dioxide, chlorine Gloxide; neutral sulfite and physical treatments such as grinding and steam pressure, The different components of rice straw (IR 36) studied were the water solubles, hemicellulose, cellulose, lignin, alkali soluble silica and sand,

The total loss in dry matter content due to each of the treatments wab also noted, Treatments using bases as well as those involving boiling like neutral sulfite and chlorine dioxide treatments resulted to loss in dry matter content amounting to between 35 and 39%, These treatments were found to have great effects on the water solubles, hemicellulose, and lignin portions of the rice straw, In addition to these components, the bases were also found to have removed a considerable amount of the alkali soluble silica,

The treatment using hydrochloric acid produced a loss in dry matter content of 18%, The treatment resulted to the removal of about 35% and 48% of the water solubles and hemicellulose contents, respectively, All the other components were barely affected,

Treatments using the oxidizing agents potassium perto- date and potassium permanganate were found to have removed about 40%, 24% and 12% of the wai solubles, hemicellulose and lignin content of the rice straw, respectively, with negligible effects on the other components, The treatments using potassium periodate and potassium permanganate reduced to losses in dry matter content amounting to 18%,

Calcium hydroxide ;/ sodium carbonate treated straw was found to have its water solubles content increase by £7% and a decrease in the hemicellulose, Mgnin and alkali soluble silica contents by 42%, 69% and 67% + respectively,

The sulfur dioxide treatment was found to have increased the water solubles content by 20% and decreased the lignin content by 33%, The Steam pressure treatment
was found to have negligible effect on the different components of the straw, In ali the treatments studied, the cellulose and the sand were found to be the most resistant portions of the straw,

The effect of each of the treatments on the rate of biogas production showed varying degrees of improvement,

Treatments using bases, neutral sulfite, ammonia, and sulfur dioxide showed marked improvements in the rate of biogas production.

The concentration of the biogas produced in percent by volume methane fluctuated between 40% and 75%, Reservable fluctuations occurred during the first 30 days of the fermentation run, The gas composition stabilized as the fermentation systems became older, The biogas produced generated luminous blue flames which were very flammable, All fermentations were run under neutral pH conditions.

The regression equations show positive coefficients for the water solubles, hemicellulose, and cellulose contents, Negative coefficients were noted for the Magnin and alkali soluble silica fractions.

Submitted to the University Library 06/07/1994 T-1329