Biogas production from wastewater streams is one of the answers to the energy and environmental needs of the future.
With palm oil accounting for approximately 36% of global vegetable oil production in 2015 and only one tonne of palm oil produced for every six tonnes processed, there is a large amount of waste and wastewater.
The palm oil industry in Thailand processes more than 13 million tonnes of palm oil material in more than 90 processing plants. Many of these treat their wastewater streams though an anaerobic process to produce biogas energy and treat their wastewater simultaneously, which provides a significant economic boost for many of these companies.
Three of the key parameters in maximising the economics of biogas generation from anaerobic systems are the quantity and quality of the biogas produced, and the management of hydrogen sulphide (H2S) formation. The addition of an alkali is a critical part of maintaining pH and alkalinity, and stability of the anaerobic system, to perform at its optimum rate.
This case study was done on a palm oil plant in Thailand that processed around 40 tonnes of palm oil per day and had a waste stream of 500 – 1000 m3 per day, which was treated by four anaerobic reactors. The effluent stream was turned into renewable power to run the plant with excess electricity sold back onto the grid. The plant has a quota it was required to supply back onto the grid and was looking for a way to increase power generation and biogas quantity from the anaerobic reactors.
Calix started with a simple lab testing to determine the correct dosing rate of ACTI-Mag for the field trial.
The ACTI-Mag showed a three-fold increase in biogas volume generated compared to control. It was found that between 300 – 400 kg / ML was the optimum dosing rate for this operation. The results demonstrated that dosing ACTI-Mag showed an increase in yield value of more than 25%, and an improvement in Chemical Oxygen Demand (COD) reduction of 25%.
The trial showed that ACTI-Mag increased the conversion of carbon into biogas by 29.6% and improved the yield value by 28%.
It also showed a 23.5% improvement in the conversion of wastewater m3 to biogas.
Ultimately, this trial gave the plant an increased return of $322,500 baht per month (over 15,000 AUD), which was a key goal for the plant operators. This was achieved thanks to the unique properties of ACTI-Mag that allow mild flocculation and improved hydrolysation.
Calix ACTI-Mag can increase the quality and quantity of the biogas coming from anaerobic
systems, and provide a significant economic boost for food processing plants and municipalities.