| Abstrakt: |
Date palm (Phoenix Dactylifera L.) pits, a by-product of date fruit processing industry, are rich in carbohydrates, protein, fat and fibers, but are also rich in phytochemicals. In this study, powders and phytochemical extract of two local varieties of date pits (Abu-Maan and Fard) were separately co-digested with municipal sewage sludge to assess impact of the additives on biogas production. The date pits ingredients were extracted using three organic solvents (Ethyl Acetate, A + W = Acetone and Water, M + C = Methanol and Chloroform). Various quantities of powders (0.05–0.47 g) of the two date pit types were co-digested with sludge. Similarly, various quantities of the chemical extracts equivalent to the quantities of added powders were co-digested with sludge. In total, sixteen combinations of date pits powders and extracts were tested in duplicates in addition to two types of control samples without powders or extracts. The results were consistent showing significant and increasing inhibition of biogas production, reduction in total solids (TS) and volatile solids (VS) removals, decline in pH, decline in ammonia concentration, and increase in phosphorus concentration corresponding to increased addition of pits powders or extracts. Compared to sludge alone, inhibition reduced biogas production by about 75% and reduced TS and VS removal by about 74%. The inhibition is attributed to the secondary metabolites in date pit that are known to have phytotoxic activity. [ABSTRACT FROM AUTHOR] |
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