Alco Bio Fuel - waste water

Waste becomes raw material

Thanks to water-link, wastewater can be reused.

Alco Bio Fuel, with its location at Rodenhuizendok in the port of Ghent, is one of the most important bio-refineries in Belgium. At the Ghent site, grains are processed into bio-ethanol, electricity, liquid CO2 and some other by-products from feed grains such as corn and wheat.

The main product is bio-ethanol, a renewable source of energy for the transport sector. Alco Bio Fuel produces around 200 million litres or 160,000 tonnes of bioethanol every year.

The most important by-product is DDGS - Dried Distillers' Grains with Solubles - a high-quality, high-protein product that is added to feed for cattle, dairy cattle, pigs and poultry, as a substitute for imported proteins from soya. Recently, Alco Bio Fuel also produces corn oil, which creates extra added value for the animal feed industry, or serves as a raw material for biodiesel.

The location at Rodenhuizendok is ideal due to its connection to roads, rail and water and makes the logistics efficient and sustainable. Raw materials are mainly supplied by ship or lighter, from Belgium or the European Union in general. In the energy field, Alco Bio Fuel has a combined heat and power system that makes it possible to achieve an energy efficiency that is 25% higher. A gas turbine produces electricity for the plant and for the grid, and the coupled recuperation boiler produces the necessary steam for the production of bioethanol.

The challenge

Alco Bio Fuel has been supplied for some time from the Induss II factory located at Rodenhuizendok. Induss supplies to Alco Bio Fuel among others cooling water, process water and boiler feed water. Alco Bio Fuel had already set a target for reusing their water maximally and asked Induss to search for waste water flows that can be recuperated.

It was decided to carry out an analysis within the company, to find out which water flows were available and which could possibly qualify for reuse. For example, we established that the drainage water from the cooling tower was simply discharged into the river water. A solution was developed to send the drain water back to Induss, treat it there and then reuse it.

In addition, it turned out that there was an important corrosion problem in the cooling tower. High corrosion rates, which caused considerable damage and caused frequent leaks to be repaired. All this led to considerable operational costs, repair costs and shutdowns. Clearly a problem had to be tackled at the base here.

The solution

A commonly used product to suppress corrosion is phosphates. However, Alco Bio Fuel has a strict standard for phosphate when it comes to discharging into surface water. In this way, they were limited in the dosage and the corrosion amount was also a little too high.

Induss came up with the solution to recuperate the drain water from the cooling tower on its installation. In this way, a higher amount of phosphate could be dosed and the corrosion problem was immediately resolved. Of course, a number of parameters had to be monitored online to ensure that they could not damage the membrane installation of Induss. After the installation of the necessary online sensors and the installation of a pipeline, a close loop was realized between the companies Induss and Alco Bio Fuel. Induss sends good water quality in the form of boiler water, cooling water and process water to Alco Bio Fuel and receives part of the waste water back from them, which is reprocessed again to a good water quality.