Composting and trickling filter for treatment of olive mill waste

Agricultural practice and improper waste disposal in developing regions have resulted in environmental degradation in land and waters, for which low-cost, proven solutions are needed. We demonstrate in the laboratory the applications of composting and trickling filter techniques to treat olive mill wastes that can be implemented in the West Bank and other regions of the world. To a pomace waste sample from a California mill, we amended with saw dust (wood carbon source) and baking soda (NaHCO3 alkalinity) at weight ratios of waste/wood/NaHCO3 at 70: 27: 1 and composted it for periods of 11 and 48 days; the compost was used as an additive to potting soil for transplanting. The pomace sample was also blended into slurry and introduced to a water-circulating pond and trickling filter system (P/TF) to examine any inhibitive effect of the pomace on biological removal of the organic waste. The results showed the compost-amended potting soil supported plant growth without noticeable stress over 34 days and the P/TF system removed BOD and COD by > 90% from the waste liquid within 2 days, with a first-order rate constant of 1.9 d(-1) in the pond. An onsite treatment design is proposed that promises implementation for agricultural waste disposal in developing regions.