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Biofouling potential reduction of waste water treatment effluents through biofiltration with Denutritor

Abstract

The project for sustainable water use in chemical, paper, textile and food industries

Descrizione

This report is a result of the project AquaFit4Use, a large-scale European research project cofinanced
by the 7th framework programme of the European Union on water treatment
technologies and processes.
Biofouling is the undesirable accumulation of microorganisms, plants, algae, and/or animals on
wetted surfaces. In industry, biofouling causes serious problems in for example membrane
bioreactors, reversed osmosis membranes, cooling water systems, pipelines, heat exchangers,
etc. Biofouling is caused by inorganic nutrients (e.g. ammonium, nitrate, sulfate and phosphate)
and organic compounds, which are dissolved in the water. These compounds promote the
growth of microbial populations and are the source of biofouling. Denutritor is a biofilter which
reduces biofouling in water systems by removing these growth substrates.
Perstorp Specialty Chemicals aims to re-use the effluent from their wastewater treatment plant
for cooling or other industrial processes. To this end, different waste water production and posttreatment
systems were tested on pilot scale. The wastewater effluent produced by the
conventional Active Sludge (AS) system of Perstorp was compared to that produced by a
Membrane BioReactor (MBR) pilot installed by Logisticon. The possibilities to remove organic
compounds, biofouling potential and salts from AS or MBR effluents largely determines the reuse
possibilities. Therefore, different post-treatment systems were tested to polish the AS or
MBR effluents: Advanced Oxidation (AOP) to reduce organic compounds; Denutritor to reduce
biofouling potential; and Reversed Osmosis (RO) to remove salts.
The objective of this work as part of SP 5 Task 5.2.2.2 was to assess the potential benefits and
risks of Denutritor, in combination with other treatment techniques, for producing recycled water
for use as process water or cooling water at Perstorp.
A Denutritor pilot installation was constructed and operated for eleven months on effluent from
the AS system of Perstorp, or on water from the MBR or AOP pilot installations. Within this
period about 3000 m3 water has been treated. When operated with AS effluent water, Denutritor
removed up to 92% of the biofouling potential. Effluent water from the MBR installation had a
five-fold lower biofouling potential than AS effluent water. With MBR effluent no further reduction
of biofouling potential by Denutritor was observed. Treatment of AS-effluent by AOP resulted in a
twenty-fold increase of biofouling potential. Further treatment of AS-AOP effluent by Denutritor
reduced its biofouling potential up to 91%.
It is concluded that Denutritor is useful as a post-treatment step to reduce biofouling potential of
AS or AS-AOP effluent, and as pre-treatment step to protect RO membranes.
Re-use possibilities
Quality requirements for process water used in chemical synthesis and for steam production are
relatively high and much effort will be needed to meet their demands. For the production of feed
water for cooling systems, AS effluent treated by Denutritor and RO seems to be a promising
alternative, especially in combination with a Denutritor system integrated in the recirculating
cooling water

TRL - technology readiness level

5 Prototipo in grande scala o scala reale.

Link1

http://www.aquafit4use.eu/downloads/

Laboratorio

TIGRI

Partner

ENEA

Topic di ricerca

2.5.2 Trattamento reflui industriali

Risultato LISEA

Falso