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Napier grass (Pennisetum purpureum), represents an interesting substrate for biogas production. The research project evaluated biogas potential production from dry anaerobic digestion of Napier grass using batch experiment. To enhance the biogas production from ensiled Napier grass, thermal and alkaline pre-treatments were performed in batch mode. Alkali hydrolysis of Napier grass was performed prior to batch dry anaerobic digestion at three different mild concentrations of sodium hydroxide (NaOH). The study results confirmed that NaOH pretreated sample produced high yield of biogas than untreated (raw) and hot water pretreated samples. Napier grass was used as the mono-substrate. The biogas composition of carbon dioxide (30.10%), methane (63.50%) and 5 ppm of HS was estimated from the biogas. Therefore, fast-growing, high-yielding and organic matter-enriched of Napier grass was promising energy crop for biogas production.

This work was conducted to study the possibility of cultivating algae for use as fish feed using vegetable and fruit canning industry wastewater treatment effluent. The results showed that Chlorella vulgaris showed successful growth in 10% initial stock solution, 20 cm water depth and for 12 days of cultivation. The algae attained a cell density of 13.72 × 10 5 cells/mL, biomass dry weight of 255 mg/L and protein content of 45.6%. Dried algae were used as a feed additive for tilapia (Oreochromis niloticus L.) cultivated in a vegetable and fruit canning industry oxidation pond. After 3 months of cultivation, fish fed 3% dried algae had a higher (P<0.05) fish survival rate and percentage weight gain than the fish fed only the commercial feed.