Anaerobic technology from Global Water Engineering (GWE) is helping Chokyuenyong Industrial in Thailand to cut effluent COD pollution levels, extract gas from its wastewater and generate green power.
The Thailand-based starch producer has been able to reduce effluent Chemical Oxygen Demand (COD) pollution levels at its cassava production plant by more than 95% while extracting sufficient gas from its wastewater to power its boilers and generate electricity for its own use as well as sell back to the provincial grid.
Processing 1,200 tons of cassava roots a day, Chokyuenyong Industrial, headed by Tawatchai Yuenyong uses GWE anaerobic technology with a capacity of 3,200m³ effluent a day.
In addition to clean wastewater technology, the installation also generates green power and carbon credit profits as well.
Chokyuenyong’s anaerobic technology-based wastewater treatment system involves an equalisation basin (total volume 1600m³) with submerged agitators, degasifying basin with agitator (24m³), in-line pH adjustment, NaOH storage tank (25m³), UASB methane reactor (active volume 4800m³) and biogas flare.
The anaerobic technology is all above-ground for simplicity and ease of maintenance.
The wastewater passes through several pre-treatment steps before entering a GWE methane reactor in which the wastewater’s organic content (COD) is digested by bacteria in a closed reactor, degrading the compounds and converting them into valuable biogas and cleaned effluent.
Biogas from the process is collected and reused as renewable fuel in the plant’s thermal oil boiler, saving money that would otherwise be spent on bunker oil. Excess biogas is used in electrical power generation.
Key benefits of the Chokyuenyong’s wastewater treatment system:
- Cut the (COD) pollution level of influent wastewater from 22,500 ml/l to less than 1125 mg/l
- Substantially cleaner discharges to treatment ponds
- Returns up to 2.7 Mw of green power a year to provincial power grid, PEA
- Saves up to 21,000 litres a day of fuel oil by producing up to 34,000 Nm³ of biogas
- Biogas is used to power boilers and heating equipment used extensively in cassava drying and processing
- Biogas generates electricity for the large amounts of rotating equipment used in processing
- Significantly reduces the plant’s carbon footprint by preventing the release of methane gas into the atmosphere
- Generates carbon credits under the UN Framework Convention on Climate Change, earning valuable internationally tradable CER certificates
Results achieved at Chokyuenyong can be even further improved by converting its solid wastes into biogas using GWE’s RAPTOR treatment system for solid organic residues.
Rapid Transformation of Organic Residues or the RAPTOR technology is a powerful liquid-state anaerobic digestion process that consists of enhanced pre-treatment followed by multi-step biological fermentation.
The process optimises conversion of almost any organic residue or energy crop into biogas, valuable electricity or heat.
Chokyuenyong Industrial President Tawatchai Yuenyong says his company’s investment program has been well justified by the outcome in terms of environmental and financial results.
CST Wastewater Solutions partners with Global Water Engineering for the installation of wastewater treatment systems at diverse locations around the world.