Table 1: Physico-chemical and heavy metals analysis of Cocoa processing industry wastewater.
| Parameter | Cocoa processing wastewater | USEPAa | NESREAb |
|---|---|---|---|
| Colour | Dark brown | Colourless | - |
| pH | 7 | 6.5-8.5 | 6-9 |
| EC | 290 | - | - |
| COD | 303 | 410 | 90 |
| BOD | 222 | 250 | 50 |
| TDS | 580 | 500 | 500 |
| Alkalinity | 62 | 20 | 150 |
| Acidity | 9 | - | - |
| Chloride | 20 | 250 | 250 |
| Ammonia | 1.2 | 0.03 | 1 |
| Phosphates | 0.04 | 5 | 2 |
| Nitrates | 1.20 | 10 | 10 |
| Sulphate | 1.69 | - | - |
| Lead | 0.9 | 0.015 | 0.05 |
| Cadmium | 0.14 | 0.005 | 0.2 |
| Chromium | 1.00 | 0.1 | 0.05 |
| Copper | 2.32 | 1.3 | 0.5 |
| Iron | 1.40 | 0.3 | 0.30 |
| Manganese | 0.81 | 0.05 | 0.2 |
| Nickel | 0.41 | - | 0.01 |
| Zinc | 10.2 | 5 | 5.00 |
NESREAa: National Environmental Standards and Regulation Enforcement Agency (2009); USEPAb: United States Environmental Protection Agency (2009); BODc: Biochemical Oxygen Demand; CODd: Chemical Oxygen Demand; TDSe: Total Dissolved Solid; EC: Electrical Conductivity. Units of the parameters are in mg/L except for pH which has no unit and EC in μScm-1.