Advanced anaerobic technology from Global Water Engineering, available in Australia from CST Wastewater Solutions is helping several industries generate millions of dollars in ongoing benefits.

Early adopters of anaerobic technology, which is used to convert waste water into green energy, are now reaping millions of dollars a year in benefits by replacing fossil fuel, producing less pollution, and achieving much cleaner effluent water.

Advanced anaerobic technology from Global Water Engineering can be used globally wherever industry has a biological waste stream or waste water with high organic carbon or COD (chemical oxygen demand) of natural origin that can be broken down into biogas by anaerobic bacteria.

GWE’s anaerobic technology, proven at more than 300 food, beverage, agro industry and processing plants worldwide, simultaneously cleans the water to high discharge standards while producing biogas (methane) to generate green electricity or to fuel boilers and other factory plant fuel consumers.

This technology has been implemented by a major producer of native tapioca starch, sweeteners and modified starch in Thailand within its wastewater plant to produce up to 70,000 Nm³ a day of biogas at 70% methane, equivalent to about 43,750kg a day of heavy fuel oil, worth $A 12.2 million a year.

The Corn Products International plant operates with a capacity of 6000m³ a day of wastewater containing 150,000kg of COD, with the anaerobic technology achieving high effluent purification levels of more than 95%, reducing COD loads from 25,000 mg/l COD influent to 1250 mg/l effluent.

Global Water Engineering CEO Mr Jean Pierre Ombregt explains that anaerobic technology is particularly effective for food, beverage and agro industry applications. He observes that generating green energy from wastewater doesn’t get as much attention as other green technologies such as wind power, but early adopters including this plant are reaping benefits year after year. The starch factory, for instance is self-sufficient for its fuel energy needs with the biogas used in four factory steam boilers, replacing heavy fuel oil.

He adds that the savings in such projects are permanent and ongoing, and the cost of typical installations can be repaid within a couple of years, sometimes even a year.

Anaerobic digestion is a biological process whereby bacteria break down organic material into more basic compounds without requiring oxygen as a component of the process.

Modern anaerobic processes vastly concentrate the process in environmentally harmonious closed reactors, operated under ideal temperature and process control to optimise waste consumption and, in the process, generate large quantities of methane from the organic materials in the wastewater. One ton of COD digested anaerobically generates 350Nm³ of methane, equivalent to approximately 312 litres of fuel oil, or about 1,400 kWh of green electricity.

Anaerobic digestion facilities have been recognised by the United Nations Development Programme as one of the most useful decentralised sources of energy supply, as they are less capital-intensive than large power plants. They can also benefit local communities by providing local energy supplies and eliminate the need for large and often smelly and environmentally challenging anaerobic lagoons.

Though most industries have not realised the potential of this green energy cash cow, applying anaerobic wastewater treatment sheds a whole different light on the cost structure of wastewater treatment infrastructure, and can now actually become a substantial additional source of income for many factories and processing plants throughout the world.