Pantaleon Sugar Cane Factory

The Processing Plant uses a simple “Once-Pass-Through” Lagoon System, with 14 lagoons in series. While they called them Oxidation Lagoons, there is no aeration being used, and we do not have a measurement of the systems dissolved oxygen levels. The influent is COD of 1,500 and BOD of 700, with the effluent at COD of 1,100 and BOD of 500. While these are certainly higher than regulations would allow if released, they use the water for irrigation and therefore are not currently being pressured to meet effluent discharge.

Their stated problem is with sludge buildup, which is exacerbated as the retention time of the lagoons significantly decreases during each production season. They currently having to dredge the lagoons between each season, as some lagoons accumulating as much as 4 meters of sludge, reducing average retention from 30 hours to 2 per lagoon.

The System consists of 14 Lagoons:

Seven Lagoons are 100m long, 50m wide, and 5m deep…25,000m3 each.

Seven Lagoons are 25m long, 50m wide, and 5m deep….…6,250m3 each.

At the beginning of the season in November, the retention time is a total of 17.5 Days…for a calculated flow of 12,500m3 per day…or 2 days for each of the larger lagoons and ½ for each smaller lagoon. By the end of the season this is reduced to a total of 28 Hours (1.17 Days).

We were not told at which time within the season that the COD/BOD data was taken; but assuming this was at the beginning, then the effluent at the end of the season in April would be very high…close to influent levels.

The stated goal is to reduce sludge, which once accomplished will also improve the overall retention time and therefore improve effluent discharge as well.

PLEASE NOTE…the fertilizer value of the discharged water will improve the growth of the Sugar Cane, and should be monitored as a cost benefit.

Treatment Plan is based on applying First Week Dosage once the lagoon has reached its top-level at the beginning of the season, and then reducing to the weekly maintenance dosage thereafter.

First Week Then Weekly

Smaller Lagoons 5 Gallons ½ Gallon

(6,250m3)

Larger Lagoons 12 Gallons 2 Gallons *

(25,000m3)

* Monitor performance, possible to reduced to 1 Gallon per week