Trinidad and Tobago taxpayers are now faced with a bill estimated to cost $200 million for repair work on anaerobic digester berms at the $226 million Beetham Wastewater Treatment Plant, which failed a decade ago. A Sunday Guardian investigation revealed the anaerobic digester berms, which formed part of the north water project, were poorly designed and led to the berms sinking at the start of construction in 2000. Newly-installed Water and Sewerage Authority (WASA) chief executive officer, Ganga Singh was the then Public Utilities Minister. The anaerobic digester berms, investigations revealed, was designed for the three lagoons expected to treat the sewerage from the city of Port-of-Spain and industrial wastewater from Angostura Ltd.
To date, construction has been halted and waste continues to flow freely into the Caroni Swamp, posing a serious health hazard on the environment and wildlife. When Sunday Guardian visited the area last week, a foul stench was emanating from the plant. Unaware of the danger, a man was seen taking a bath in the murky water.
Problem detected after commissioning
Further investigations revealed it was after the Beetham Wastewater Plant was commissioned that officials realised they were unable to treat Angostura industrial waste. A WASA official revealed: "A decision was taken and part of the proposal was to take Angostura wastewater directly into the anaerobic lagoon but when they started building the lagoon the berm failed and that part of the project was never completed. "The berm failed because it was not properly done and now this part of the work is estimated to cost another $200 million. For the last ten years Angostura industrial wastewater has been contaminating the Caroni Swamp."
Confirming the failed project, WASA's communications specialist Ellen Lewis said the company was considering other forms for treating industrial wastewater. Lewis, however, said industrial waste from Angostura Ltd was being artificially treated at the four old lagoons that they had disposed of. "The Angostura waste is artificially being treated at the old lagoons which had been used to treat wastewater from the greater Port-of-Spain area before the new plant was constructed," Lewis said.
High concentration of pollutants
Investigations revealed the plant was designed to treat approximately 75 million liters of sewerage on a daily basis from Port-of-Spain and environs, and 1,500 cubic meters of wastewater from Angostura Ltd.
The official further explained: "Even though it is only 1,500 cubic meters of wastewater it has a high concentration of pollutant. For every litre of Angostura's industrial wastewater the biological oxygen demand is 50,000 milligrams in comparison to sewerage, which is only 300 milligrams. Therefore, one litre of industrial wastewater is almost equivalent to 165 litres of sewerage. Clearly, the wastewater is highly contaminated."
Sunday Guardian learnt that due to the failure of the anaerobic digester berms the sludge that is generated by the waste is unable to be treated. "The sludge is also highly pollutant so it cannot be disposed of unless it is treated. This is where it was found that there was an urgent need for anaerobic digester berms because when it is treated, like a septic tank the volume is reduced and then disposed for landfill or manure. The project was to remove the sludge from the old lagoons that have been existing for more than 20 years, do the concrete lining, build the berms and put a cover on top of the lagoons so you can have anaerobic treatment," the official said.
Angostura responds
When contacted, Angostura's communications specialist Giselle Laronde-West admitted that WASA informed the company that the digester berms had failed and they have been seeking alternative options.
Laronde-West said the company was informed that WASA continues to treat the waste while personnel carry out a rigorous monitoring plan on the treatment plant. In addition, Laronde-West said only a few months ago EMA officials visited the Beetham Wastewater Plant to view the process. Laronde-West said the lagoons are specifically designed anaerobic ponds for treatment of industrial waste with natural filtration and do not need to be covered.
EMA: Angostura being investigated
Whether Angostura and WASA are both in breach of Environment Management Authority (EMA) standards, communications specialist Karryl Whitehall said the matter was being investigated. "At this point the EMA is looking at Angostura Ltd effluent discharges with a view of Angostura Ltd complying with the water pollution rules. The EMA has water pollution rules that organisations have to comply with. We are looking at Angostura Ltd," Whitehall said.
About treatment
In wastewater treatment the absence of oxygen is indicated as anoxic; and anaerobic is used to indicate the absence of a common electron acceptor such as nitrate, sulphate or oxygen. An anaerobic adhesive is a bonding agent that doesn't cure in the presence of air.