Black dirt from Belize Sugar Industry (BSI) sugar processing factory. Study on Cleaner Production Opportunities for the Sugar Industry in Belize, by Santos Chicas, National Central University, Taiwan ROC, June 17, 2008 indicates, that during clarification of the cane juice, impurities are removed. Lime and heat are used as the clarifying agents. Lime in solution form is added to the juice with subsequent heating to 220 deg F followed by settlement of the impurities as mud in tanks called clarifiers. Careful control of the temperature and pH levels (7.0 - 7.2) of the juice allows suspended matter to conglomerate and settle out as mud: to improve the settling rate, a small amount of flocculant solution (3 to 4 ppm) is added to the limed and heated juice immediately before it enters the clarifiers. The settled mud in the clarifiers is pumped out and filtered on rotary vacuum filters to de-sweeten it by washing and filtering under vacuum. The filtered juice circulates back to the clarifiers for further clarification, and the filtered mud is scraped off the surface of the filter drum and discarded on mud carts to the fields for fertilizer or for land fill. In our case, the weathered filter cake material was trucked from BSI. David Dyck noted the material comn not be used immediately, but needs time and rainwater leachout of chemicals before it is suitable to use as a soil amndment.
The referenced source indicates that to improve the COD removal efficiency of the wastewater treatment plant, it is recommended that the sludge is removed from around the ponds and deposited on a site far from any other water or wastewater source. The site where this sludge is then deposited needs to be located in an accessible area; so that cane farmers can reclaim and use the sludge to improve the soil texture of their sugar cane plantations.