Sewage sludge reuse with Phosphate recovery and heavy metal absorption with an innovative HTC technology.

Projektbeschreibung

Eine kostengünstige Alternative zur Klärschlammbehandlung

Die Aufbereitung kommunaler Abwässer hat sich in den letzten Jahrzehnten in allen Teilen Europas verbessert. Der größte Teil des Abwasserstroms, der in eine Kläranlage gelangt, wird abgeleitet und kann wiederverwendet werden. Der Rest ist eine verdünnte Aufschlämmung von Feststoffen, die von der Kläranlage aufgefangen wurde und als Klärschlamm bezeichnet wird. Die Verbrennung gilt als die sicherste Entsorgungsmethode für Klärschlamm, ist jedoch relativ teuer und stellt eine technische Herausforderung dar. Das EU-finanzierte Projekt HTCycle wird eine bessere Alternative zur Verbrennung aufzeigen. Es wird eine patentrechtlich geschützte Technologie für die hydrothermale Karbonisierung vermarkten, mit der sich die Menge des Klärschlamms, der in hochwertige Produkte wie Kraftstoff, Aktivkohle für die Wasseraufbereitung, Phosphor und Bodensanierungsmaterialien umgewandelt wird, erhöhen lässt.

Ziel

Efficient municipal waste-water treatment, such as the systems currently in place in most European municipalities, produces vast amounts of sewage sludge. The latest data collected show a yearly production of 9.637 thousands of tons in the EU28 countries. Sludge treatment issues are often neglected in comparison with water-related parameters which results in serious technical difficulties and highly expensive disposal methods. As a result, an energy efficient, environmentally sound and economically viable process for sludge disposal and reuse of valuable resources e.g. phosphorus hardly exists.
The most common disposal methods for sludge are spreading on agricultural soil, composting and incineration. Land-filling has been long banned, the use as fertilizer, although very moderate in costs, is being banned in many regions due to concerns about contamination of soils with heavy metals and endocrine disruptive compounds. Composting raises the same concerns, and it is a labour-intensive and unsafe process, which leaves incineration as the most used option, albeit an expensive and not effective one. Incineration entails the highest costs (80-110 € /ton), but is also considered the safest disposal method and is fast growing and widely adopted. It presents also technical difficulties, such as the low overall efficiency of the process, the huge logistic efforts required to transport the sludge to the incineration plants, or the disposal of the ashes after the sludge has been incinerated.
In this situation, our company, AVA has the objective to demonstrate and commercialize our proprietary technology for hydrothermal carbonization (HTC) of sewage sludge, showing clearly technical and economic ad-vantages against the current sludge incineration method. We aim to increase the amount of sludge converted into high value products such as fuel, activated carbons for water treatment, recovered phosphorus, soil remediation material, carbon sequestration schemes and other applications. The HTCycle process turns the present sewage sludge disposal (incineration) from a costly process into an income-generating activity.