On the tools WASTEWATER PUMPS
WASTEWATER PUMP selection and sizing
In the second of this training series on working with small bore wastewater pumps, Saniflo gives guidance on pump selection and sizing.
C
orrect pump selection is critical to ensure an optimal result. Selecting the right pump is based on several factors including the type of application, incoming flow volumes, temperatures, how high and how far waste will need to be discharged, along with considering any possible future requirements.
Domestic applications Within domestic bathroom applications, macerators are required to take waste from toilets, basins, showers, baths and bidets or a combination of these fixtures. Domestic greywater pumps are required to take waste from kitchen sinks and dishwashers, laundry tubs and washing machines or a combination of these fixtures. Combined black and grey lifting stations can take waste from multiple fixtures, including whole of house, and are designed to be installed remotely from sanitary fixtures.
Commercial applications Commercial macerators are designed for larger numbers of users or when higher vertical lifts are required. Commercial greywater pumps must be used for office fit outs or cafés where there are higher usage or higher temperature requirements. Commercial lifting stations are to be used in situations where multiple fixtures need to be fitted to one pump, when increased discharge rates are required or higher temperatures would be encountered.
Selecting a pump for high temperature applications Domestic and commercial greywater pumps will not be suitable for the higher temperatures of a commercial dishwasher, wok burner, or a glass washer. It is essential to select the right pump as these high temperatures can have a negative In hairdressing situations, the recommendation is to install a dedicated hair trap prior to the greywater lifting station.
effect on the pump’s vital components and may void the manufacturer’s warranty. Depending on the pump manufacturer’s specifications, a commercial greywater lifting station would normally be selected to accept waste with temperatures up to 90°C (per cycles of appliance) and would be necessary for commercial installations.
Autoclaves Autoclaves (used for dental and medical instrument sterilisation) generate waste often far in excess of 90°C. Instrument sterilisers and autoclaves must discharge over a tundish prior to the cooling tank or in accordance with AS/NZS 3500.2 Clause 13.21.
Commercial kitchens Grease and fats in cooking can also be an issue. This can be especially detrimental for under sink greywater lifting stations with larger holding capacity or higher activation levels. These two factors may result in the cooling and solidification of fats and oils. a) Solidification can impair operation and activation b) The build-up of sulphide gases can become an odour and health issue. In these situations, using a commercial lifting station with high temperature handling and lower activation levels in conjunction with a commercial dishwasher is crucial in the discharge of greasy wastewater to minimise solidification.
Hairdressing and beauty salons With a hairdressing or beauty salon, hair may bind with the various hair or beauty treatment products creating a ‘clumping’ effect. These clumps can cause blockages in the smaller apertures of a greywater pump. In these situations, the recommendation would be for a commercial greywater lifting station used with a dedicated hair trap installed prior to the lifting station. Consideration must be given to pump installation environments. Controlled usage would generally be in domestic situations where users are aware of a pump being employed and make use of fixtures accordingly. Workplaces or public amenities are examples of uncontrolled usage sites and one will need to factor this into pump selection as these elements present an increased risk for blockages. Pumps in these situations often require features like alarms, heavy-duty grinders, backup motor functionality or vortex (bladeless) discharge capability.
Visit the Saniflo plumber portal link: www.saniflo.co.nz/plumberportal
nzplumber
41
