Septic Tank Water

What types of wastewater are discharged?

A septic tank can contain different types of water. These types of wastewater are distinguished based on the waste products that end up in the water.

With septic tanks, the following waters are distinguished:

  • Black water
  • Grey water

Black Water

This is the case when only toilets are connected. Black water is toilet flush water that consists of rinse water, urine and feces. Black water owes its name to the colour it usually gets from the waste products it contains.

This type of wastewater contains the following substances, among others:

  • organic substances
  • fertilizers
  • drug residues
  • toilet paper
  • hormones
  • pathogenic bacteria from urine and faeces
  • large amount of rinse water

Grey Water

Grey water consists of a collection of bath water, shower water, washing machine water, dishwasher water and water from the sink in the kitchen. In practice this means all the water that is flushed away in the house (except for the toilets). Grey water has a very diverse composition compared to other wastewaters. This is of course due to the fact that many different systems are connected to it. In terms of wastewater treatment, it is important to know that there is soap in the water.

This water may consist of the following substances, among others:

  • Soap residue
  • Metal particles from the pipes
  • Copper particles from the pipes
  • Cosmetics
  • Hair
  • Skin Flakes
  • Fat
  • Cleaning products
  • Food waste
  • Detergent/Dishwasher detergent

Other types of wastewater

You may also come across the terms yellow water and brown water, although these are not often used. Yellow water is urinal water containing only urine. Brown water consists only of faeces. This type of wastewater only occurs when only urine is discharged into the tank. Each septic tank consists of bacteria (microorganisms) that break down the wastes in the discharge water so that it can meet the discharge regulations. However, every type of wastewater is different. For example, bacteria have a much harder time breaking down black and gray water as opposed to yellow and brown water. This is because these types of wastewater also consist of chemical substances. Substances that the bacteria may have much more difficulty breaking down. It is therefore wise to have the septic tank maintained regularly and to add extra bacteria in case of inconveniences like odour/clogging to improve the functioning of the septic tank. Prevention is better than cure? Therefore we have a number of (maintenance) products to improve and maintain the performance of the septic tank.

Our recommended products for your septic tank