Bioaugmentation zur Eliminierung abgeschiedener Abfallfettfrachten aus Gastronomieabwässern

Lipids (fat, oil and grease) cause disturbances in both public sewer pipes and wastewater treatment plants. The pretreatment of sewages with high lipid loads is absolutely important in order to prevent damages. Bioaugmentation technology, i.e. the use of microorganisms, turned out to be a means to increase the performance of conventional grease traps. Various microorganisms were evaluated regarding their ability to degrade fat oil and grease within a grease trap. Subsequently the biological degradation of waste fats was studied in different experimental scales. Lab scale experiments in batch culture showed that a mixture of different microorganisms (Yarrowia spp., Candida sp., Rhodococcus spp. and Pseudomonas sp.) eliminated 70% of applied waste fat within 24 h and 90% in 14 d, respectively. Thus, the mixed culture eliminated 7.2 g FOG/l*5d-1 at a volumetric loading of 8 g FOG * l-1. In comparison, autochthone microorganisms eliminated 57.4% (129.5 mg) of the applied FOG within 14 d. In contrast to the work of (Brooksbank et al. 2007), the abiotic controls showed only a minor decrease of extractable FOG over the experimental time, i.e. 7.5% (15 mg FOG) of the applied waste fat within 14 d. In summary, the lab-scale experiments demonstrated that pure cultures are less suited for the degradation of fat than complex mixed cultures. In a fat separator model (scale 1:10) developed for this purpose a number of improvements were tested in order to modify a conventional grease separator in order to provide a system suitable for successful bioaugmentation. The tests showed that Rhodococcus erythropolis and Candida cylindracea were able to establish themselves inside the simulator. The FOG loads were almost completely eliminated over the test period of 147 d. Although the COD increased in effluent samples over the time, the content of FOG decreased (600 mg FOG/L at the beginning of the test period, 280 mg FOG/L after 90 days). Bioaugmentation studies were carried out in pilot scale using a modified grease separator, type „TOPO SF/E 2/200“ downstream of a restaurant kitchen facility. The pilot plant worked without technical disturbances over the whole test period of six months. Unfortunately, the first two bioaugmentation campaigns were not successful. Contrary to the results obtained in lab scale experiments, the microorganisms were not able to establish themselves in the system due to drastic changes of pH (3-12) in all compartments of the grease separator. These extreme pH levels were not expectable, because they are illegal and prohibited by constitutions and prescriptive limits of the municipal administration. The pilot scale studies displayed that the prescriptive limits were neither attained with nor without the bioaugmentation system. As of now, the technical practice prevents the successful operation of implemented bioaugmentation. The use of neutral detergents and a separated disposal of disinfectants should allow for the future use of bioaugmentation processes to eliminate grease loads within a grease separator.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2009

Author dc:creator

• Hommes, Gregor

Contributors dc:contributor

• Schäffer, Andreas

• info:eu-repo/classification/ddc/570
• Biologischer Abbau
• Fett
• Fettabscheider
• Gaststättengewerbe
• Mikroorganismus
• Abwasser
• Abwasseranalyse
• Abwasserbiologie
• Abwasserbeseitigung
• Abwasserreinigung
• Biowissenschaften, Biologie
• Bioaugmentation
• Abfallfett
• Mikroorganismen
• fat
• oil
• grease separator
• elimination

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-124618%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:63164