International Journal of Applied Microbiology and Biotechnology Research
ISSN: 2053-1818
Vol. 6(2), pp. 15-21, February, 2018

Composting of agricultural residues with olive mill waste and rock phosphate to reduce environmental pollution and enhance phosphorous release

Talaat N. El Sebai1, Abd El-Nasser A. Khattab2 and Adel G. Abdel-Razek3

1Agricultural Microbiology Department, National Research Centre, Cairo, Egypt.
2Genetics and Cytology Department, National Research Centre, Cairo, Egypt.
3Fats and Oils Department, National Research Centre, Cairo, Egypt.

*To whom correspondence should be addressed. E-mail:

Received 21 December, 2017; Received in revised form 14 January, 2018; Accepted 23 January, 2018.


Agricultural residues, Compost, Olive mill waste, Rock phosphate.

Olive mill waste (OMW) is one of agricultural residues (AGRs) that has serious environmental hazards emanating mainly from its phytotoxic phenolic components. This study investigated the feasibility of producing compost with reduced phenolic content and increased available phosphorus. Other composting effects on compost constituents were also evaluated. Four piles were constructed using AGRs as basic constituents, 4% of RP was added to each pile. Different rates of OMW [4.2, 2.9, 2.2 and 0 % (v/v)] were added to the compost piles. Turned windrow method was applied in the composting process. Compost samples were collected from each pile at 0, 45 and 90 days then composite sample of each was analyzed to determine the total phenolic content (TPC), available phosphorus (AP) and other compost parameters. The results obtained demonstrate that the percent reduction of TPC was affected by pile size since 57.97 and 50.56% in piles (1 and 2) versus 29.52 and 23.01 in piles (3 and 4) of TPC was dissipated at 45 days, these values were slightly changed in piles 1 (57.85%) and 2 (51.87%) while, great changes were recorded in piles 3 (43.07%) and 4 (48.4%) after 90 days of composting time. Also, AP release was significantly affected by composting time since it increased from 14.41, 32.49, 35.63 and 32.46 ppm at 45 days to 45.85, 52.4, 58.95 and 46.64 ppm at 90 days in piles 1, 2, 3 and 4, respectively. The other characteristics of the end product of all piles were within the range of standard compost with C/N ratio ranging from 14.44 to 17.11, pH around neutral and with acceptable organic matter and NPK content. The final product of all piles was free from pathogenic nematodes and weed seeds. It can be said that co-composting of OMW with RP-enriched AGRs can lead to a significant reduction of TPC and release of AP from RP; and the end product can be safely used for soil amendment/fertilizer.

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