The Course Map: Water In, Use, Effluent, Discharge
A single picture of the water path on a site, and the decisions a competent practitioner makes at each stage.
11 min
Activities: 0 of 2
Every site that uses water is part of a larger water system. Water arrives from a supply. The site uses it in processes, cleaning, cooling and welfare. Some of it leaves as product or as vapour. The rest leaves as effluent: used water that carries the materials the site added to it. That effluent goes to a sewer, to on-site treatment, or directly to a river, a lake, the sea or the ground.
Water management and effluent management are often given to different people. One person looks after the water bill. Another person looks after the discharge. In practice they are one system. Every litre you do not use is a litre you do not have to treat. Every kilogram of material you keep out of the water is a kilogram you do not have to remove later.
Who this course is for
The course is written for people who already know the basic ideas and now need to apply them: environmental coordinators, production and utilities supervisors, treatment plant operators who want the wider picture, and HSE (health, safety and environment) advisers. You will be asked to choose between options, diagnose problems and explain trade-offs, not only to define terms.
The water path on a typical site
- 1
Stage 1
Source
Mains supply, a borehole, surface water abstraction or harvested rainwater. Each source has a cost, a quality and sometimes a licence.
- 2
Stage 2
Use
Process water, cleaning, cooling, steam, product, and welfare. This is where most waste and most contamination happen.
- 3
Stage 3
Collection
Drains, sumps and pipework carry used water away. The drainage design decides where every spill ends up.
- 4
Stage 4
Treatment
On-site treatment removes some of the load before discharge. Sometimes the public treatment works does this instead, for a charge.
- 5
Stage 5
Discharge
Effluent leaves the site at a consented point, within limits, and is sampled to prove it.
- 6
Stage 6
Receiving environment
The sewer, river, sea or ground that finally receives the water. Its condition is the reason the limits exist.
Where control is cheapest
Control is cheapest early in the path. Fixing a dripping hose at Stage 2 costs very little. Treating the extra volume at Stage 4 costs energy, chemicals and sludge disposal every day. Cleaning up a river at Stage 6 can cost far more than both, and it may bring prosecution.
Worked example 1. A bottling plant sends sugar-rich rinse water to its treatment plant. The plant struggles every summer. The team first plans a larger aeration tank. Then an operator notices that the first rinse of each tank holds most of the sugar. The site collects that first rinse separately and sells it as animal feed. The treatment plant now works within its design load, and no new tank is needed.
Worked example 2. A warehouse has no process water at all, so the manager believes water is not an environmental issue. A heavy storm washes diesel from a leaking forklift refuelling point into a surface water drain and into a stream. The site had a water risk; it simply sat outside the building.
At which stage of the water path is control usually cheapest?
Put the water path in order
Arrange the stages from first to last.
- 1Use
- 2Receiving environment
- 3Treatment
- 4Source
- 5Discharge
- 6Collection