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Industrial catering effluent

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Many people regard all drains as drains and do not realise the difference between storm water and waste water or 'effluent'.

Storm water is...

...from rain that falls on roofs, pathways and roads, and drains away to the nearest natural water course, and eventually to the sea. To accommodate leaves and refuse in uncleaned gutters, storm water pipes are usually of large diameter to prevent blockages.

Effluent is...

...waste water from human activities – washing, cooking, industrial activities – and drains to some sort of waste water treatment  plant [device] that could be very small in rural areas (such as a simple soak pit) to very large (like the sophisticated municipal treatment plants that are designed to cater for many millions of litres of waste water per day) in metropolitan areas.

What is catering effluent?

Catering effluent is dirty water that drains from food preparation areas and has two principal charactaristics:

  1. Hydraulic load - the amount (volume) of water passing through the drains. This is often predictable for specific times of the working day, heaviest during washing and cleaning cycles.
  2. Organic load - the amount of biodegradable organic waste. This is not always so predictable as it depends upon the number of meals served and usually peaks during pre-prep and cleaning cycles.

This type of waste water is common, in varying degrees, to all households, restaurants, butcheries, food factories; in fact anywhere food is prepared or cooked for consumption or sale.

Why 'industrial'?

Because that term is defined as: 'any person who engages in the activity of preparing food for sale and or profit'.
The pre-treatment of catering effluent streams (floor drains, grease traps etc) is similar whether from a restaurant kitchen in town, a food factory, or a butchery or bakery in the country. Treatment is all much the same, because it deals with products of kitchens where food is produced and/or prepared.

The process procedure

The difference is in the final processing of the liquid waste...

Within a municipal/commercial district (industrial)

In urban districts most catering outlets are served by, and drain to, municipal sewage treatment works. These are usually large, catering for thousands of people, with considerable volumes of grey water passing through them wherein high COD effluents - typical from food processors and especially butcheries (blood has a high 'hard' COD) - become diluted. These large 'works' are able to accommodate high 'fat loads' in the relatively small discharges produced by the food and beverage industry when mixed in with wash water from industrial and domestic sources.

Outside a municipal district (agricultural)

Here the combined effluent from a few people, often 3-30 persons, ends up in a septic tank or small 'package plant' - both of which are commonly inadequate to cater with quantities of raw catering effluent. This is often combined with the fact that there is no low COD wash water to dilute the impurities in the waste water stream. It is therefore essential for the owner to ensure that grease traps and interceptors are adequate for the task and that they are managed responsibly. If not, expensive malfunctions of the drainage system will result.

Critical points:

  1. Only sewage (black water) goes to the septic tank.
  2. The hydraulic load is controlled - the grey (wash) water goes directly to the soakaway, we recommend via a grey water recycling plant.
  3. The correct BIO-SYSTEMS COD reducing additives are used to assist with degrading the organic load.

For more on how to prevent system failure read Rural catering effluent.

Managing industrial catering effluent

There are usually two parts to catering effluent:

  1. Solids - food scraps, plastic packaging, kebab sticks, tea spoons and so on, washed along the drains by the dirty water (it's amazing what you find in grease traps!). These are relatively easy to trap and remove in the correctly designed interceptors.
  2. FOG (Fats Oils and Greases) - are more difficult to separate and remove as very often they are emulsified in the waste wash water. FOG causes odour and poor water quality, leading to health hazards in contravention of local bylaws.

BIO-SYSTEMS products used to treat catering effluent

    The B220 powder product range is supplied in bulk for improving the quality of large industrial effluent systems where high grease loadings are experienced. These include most meat and fish processing plants as well as manufacturers of soups, confectionary, synthetic bread spreads, etc. Supplied in soluble 250g pouches, B220 is easy and clean to apply and re-hydrates within the stilling tank or grease sump within 30-40 minutes, when it commences degrading the COD. For more information on BIO-SYSTEMS B220 contact
  2. BIO-SYSTEMS FogFree (FF200)
    FogFree is a DIY version of B220R, compiled and marketed for use in kitchen grease traps in hotels, restaurants and fast food outlets. Safe and easy to use, it is compounded from a complex mixture of natural microbial powders that have been blended to degrade FOG in kitchen drain interceptors and grease traps. FF200 is distributed in soluble 25g pouches and is particularly suited for use in the stilling tanks of traps where it has time to form a viable biomass that will feed on the FOG, breaking it down into natural gasses and water. There is no residue other than inherent, inorganic molecular radicals that fall to the floor of the stilling tank to form a silt that must be removed when it becomes over 25mm thick – usually every six months or so, when a 'deep clean' and visual inspection of the entire drainage system is advised. For most catering effluent, FF200 is the answer. Just one of the nine x 25g soluble pouches in a FF200 pack per week will maintain the average busy restaurant or supermarket trap in good working order. The dosage must be increased proportionately under heavy (peak season) loads. Find out more at
  3. BIO-SYSTEMS DrainFlow 60 (DF60)
    DF60 a concentrated liquid product intended for drain points (floor drains, wash troughs, sinks, showers, etc.) where it degrades slimes on the inside of pipes, thereby preventing blockages and odour. Typically it is applied at approximately 10ml-20ml twice a week. This product can be 'auto-dosed' by a dispenser.
  4. BIO-SYSTEMS Dop-a-Day
    Dop-a-Day is a 'small-user' version of DF60.
  5. BIO-SYSTEMS L2120  
    L2120 is an industrial version of DF60 for use in food factories, abattoirs and on sewage spills. It has the ability to rapidly counter drain odours.
  6. BIO-SYSTEMS Hard Surface Degreaser (HSDG)
    This non-toxic, aqueous detergent is a remarkable inexpensive fat-encapsulating degreaser used for de-fatting floors and inceptor casings.  It is compatible with bacteria living in the drains, which it does not harm. HSDG removes the fat and grease from the pollution equation.

Click on the BIO-SYSTEMS Product table for a complete list of products. Also see our Catering effluent case history.

Marble top stained with fat  Marble top stained with fat

Marble top treated with HSDG  Marble top treated with HSDG

Go to Grease traps and interceptors, Oil spills, Odour prevention and Drain dos and don’ts for more on the industrial effluent disposal system.

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