Assessment of grease traps used in food services sector in Auckland

Abstract

Fat, oil and grease (FOG) deposits in sewer systems is becoming a serious concern water industry. These deposits can come from both domestic and commercial wastewaters. Watercare has reported that 70% of the sewer blockages (in Auckland) is due to the material such as rags, wet wipes, wood, tissues, hygiene products, etc. that shouldn’t go down the flushing drain. These material can lead to blockage of pipes when combined with FOG. This study was about assessing the grease traps (GT) that are being used in food services sector in Auckland.

The purpose of this study was to address the key questions: (i) How FOG deposits are actually formed? (ii) What type of grease traps are used in small scale food service sector and how effective they area in terms of removing FOG at the source? (iii) What are the issues and/or what is missing in terms of operation and maintenance of GTs?

A questionnaire was prepared to collect data such as type of food service, type of GT used and their sizes, type of fixtures that are used in the kitchen area, etc. This study showed that there are some issues re the way the GT are operated, maintained, and monitored (i.e. some regulatory gaps). The study also reviews the current compliance practice, and then provide some solutions that could lead to reduce FOG at source in order to mitigate pipe blockages