Constructed wetland and wastewater management for TPC.
The Tanganyika Plantation Company Ltd. (TPC) is considered to be one of the largest sugarcane estates in Tanzania. The extraction of sugar from the plant requires a substantial amount of water and results in a number of useful and unusable by-products. Wastewater from the factory contains solid and dissolved organic matter, lubricants/oils and caustic soda used to clean the factory. Traditionally, factory effluent was stored in a ~2 ha reservoir before being discharged. The effluent reservoir had a bad odour. To improve how wastewater was processed at the factory, TPC appointed GroundTruth to assess the feasibility of creating an artificial wetland to treat the effluent stream originating from the factory.
The objectives of the integrated constructed wetland would be to promote:
- Reduced odours from the effluent reservoir;
- Increased availability of decontaminated water for irrigation purposes;
- Improved wastewater quality to allow its use as a source of within the nearby Namalok nature reserve, accounting for hydrocarbons (e.g., oil and grease), suspended solids, biological and chemical oxygen demand, nitrogen and phosphorous contamination, heavy metals, and bacteria;
- A suitable source of biomass (from the wetland habitat) for utilisation within the factory; and
- Potential use of the treated effluent stream for irrigation.
Ultimately, through in-field surveys, literature review, Graphics Information System (GIS) processing, review of the available water quality data, specialist input, and complex desktop modelling, GroundTruth developed a series of detailed recommendations for both factory operations and effluent treatment, among other observations in a comprehensive assessment report.
Recommendations for factory operation included implementation of sand oil and grease traps, methods to mitigate fly-ash and bagasse contamination of the effluent stream, stormwater management protocols and considerations, caustic soda and formic acid flushing, areas where additional issues with spillage were occurring, methods for improved general waste disposal, and switching to environmentally friendly product use where possible.
Recommendations for effluent treatment included specific treatment best practice advice for fly-ash contamination, caustic soda and formic acid, oil and grease traps, and stormwater runoff.
Furthermore, GroundTruth provided a conceptual design for the integrated constructed wetland system.