Plumbers often encounter wastewater. Wastewater is a common everyday problem that can result in costly water damage. Especially when the water reaches a material resulting in rotting of wood, rusting of steel, delaminating of materials, etc.

The accumulation of wastewater can also be immensely frustrating on a job site. The wastewater can be caused by rain, flooding, burst or leaking pipes, or simply just groundwater seeping through.

There are three basic categories of wastewater, based on the level of contamination:

Classified as "clean water" as it does not pose a substantial threat to humans. Where this is commonly found is from broken water supply lines, tub/sink overflowing, or water supply lines’ appliance malfunctions.

Known as "grey water" occurs when a source contains a significant degree of chemical, biological or physical contaminants. This may cause sickness when consumed or exposed to. Examples of where this is found are sump pump failures, seepage due to hydrostatic failure, water discharge from dishwashers, etc.

Known as "black water" and is grossly unsanitary. This water contains unsanitary agents such as harmful bacteria and fungi, which causes severe sickness. Category 3 Wastewater are contaminated water sources that affect the indoor environment. This category includes water sources from sewage, seawater, rising water from rivers or streams, ground surface water, or standing water. 

Category 2 Wastewater that is not promptly removed from the structure and or has remained stagnant may be reclassified as Category 3 Wastewater.

The removal of wastewater is often challenging, in most cases the water needs to be pumped out. Depending on the circumstances, there are two types of pumps that are used for this application: fuel-driven pumps and electrical submersible drainage pumps. Both these pump types are generally low pressure, high volume pumps for the purpose of draining water quickly, and each having their own advantages and disadvantages.

As the name implies, these pumps are driven by either Petrol or Diesel engines that in turn rotates the pump shaft, turning the impellor and pumping water. These units are installed above the water line and draw the water with the use of a suction pipe/hose, it is important that the size of the suction pipe is no smaller than 50mm.

These pumps are mostly used for category 1 to category 2 wastewater but upon request pumps for Category 3 Wastewater are available

Advantages of fuel-driven pumps:

- No power or power cables required
- Easily removable and stored away
- Economically viable
- Cost-effective maintenance when using reputable brands like Honda or Powermaster
- Durable and robust
- Due to pipe diameter, usually 50-100mm, the pump can draw water from very narrow sumps.
- Up to 6 hours of continuous pumping based on a 5-liter fuel tank.
- Depending on the specific type of fuel pump (trash, slurry, or clean water), can pump suspended solids of up to 32mm

Disadvantages of fuel-driven pumps:

- Cannot be used indoors, carbon monoxide exhaust fumes can be harmful
- Suction depth (the difference between the pump inlet and water level) is limited to between 1 and 3.5m
- Fuel contamination is a possibility
- A petrol pump needs to be serviced; a pump that works in a dusty area will need to be serviced more regularly than a pump that works in a “clean air” environment.
- Fuel driven pumps could be a fire hazard
- Pump unit must be primed before use

It is worth noting that there are two types of fuel-driven pumps: petrol and diesel. The main differences are:

- Diesel driven pumps are considerably more expensive, in some cases double the cost
- Diesel driven pumps have fewer spare parts than that petrol, therefore spare parts are more readily available
- Diesel driven pumps are a lot more robust and reliable
- Fuel consumption is less with diesel
- Diesel is safer to operate due to diesel having a lower flashpoint, therefore “less” flammable

Agrinet stocks a variety of pumps suited for the applications mentioned above.

Drainage pumps are a sealed pump unit that is installed underwater, with the use of an electrical motor that rotates the shaft and in turn the impellor, water is drawn in through the bottom of the pump and then pumped through a delivery hose, no smaller than 50mm, out of the desired area.

These pumps usually come complete with a float switch connected so that unit that will automatically switch off the pump if the water level gets too low.

Advantages of a Drainage pump:

- Quite easy installation. No suction hoses required, only a delivery hose
- Speroni Cutty has an internal blade that chops up solids in the water.
- Pumping heads up to 12m
- Can be used in all weather conditions
- Pumping solids up to 50mm, depending on pump type, therefore up to category 3 wastewater can be pumped.
- No priming needed

Disadvantages of a Drainage pump:

- Limited pressure
- Power supply needed
- “Bulkier”, so space limitations apply
- Drainage pumps that have a float switch are not to be used in continuous duty applications!

Agrinet stocks Speroni drainage pumps, which have been tried and tested in South African conditions for decades both in the Agricultural and Industrial sectors.