Our range of activities include: technical design, distribution, installation, and maintenance of water-supply, sewage, and measuring/control systems with a 24-h technical support.


Waste water treatment plants

Each of us generates wastewater on a daily basis. In 24 hours, one person uses an average of 100 litres of water for personal needs; of this volume about 50-60% is used for hygiene (bathroom).

Immediately after usage, regardless of location, it becomes "waste" and is discharged from the residential area. If the dwelling is connected to a sewage system, water reaches a municipal wastewater treatment plant. If a dwelling is not connected to the sewage system, then water must be treated – the process by which water is being brought as close as possible to its original state – and then reintroduced into the natural cycle (discharged).

Wastewater contains solid suspensions, organic compounds (animal remains, vegetables, fat, etc.), other nutrients (nitrogen, phosphorus compounds, etc.), and various chemicals (detergents, cleaning agents, disinfectants, etc.) that must be removed before discharge.

AquaClean S series

AquaClean S series – is the new family of compact mini-plants, for domestic wastewater treatment, using the SBR (sequencing batch reactor) principle. The plant and the quality of treated water meet the requirements of the national law. The reliability and capacity to ensure the requirements on the quality of the treated water depend on the chemical/ biological efficiency and on the specific operating conditions (flow and volume of discharged water, temperature, composition of inlet water - influent).


S-Series is designed both to equip new dwellings and to re-equip existing septic tanks, with minimal changes. In particular, they were designed to treat domestic wastewaters from households with a capacity of 1,000 litres (S5) or 1,500 l (S10)/ every 24 hours (equivalent to 1–6 (S5) and 7–12 (S10) permanent residents). The plant can handle only domestic wastewaters. Water stored inside the plant must not contain chemicals that may harm the bacteria population.

The plant cannot be fed:

  • Industrial wastewater
  • Rainwater or recycled water from swimming pools, etc.
  • Water containing aggressive chemicals, scrap petroleum, oils, etc.

The S series is an enhanced version of a treatment plant operating on the SBR principle, using an activated sludge and physical separation by settling treatment combination. This is done in 4 operating cycles/24 hours, each in four stages:

  1. Intake - At the beginning of the treatment cycle, the supply pump brings from the first chamber a calculated volume of water. If the level in the first chamber is low, the plant switches to holiday mode throughout the entire cycle (6h).
  2. Treatment – Following supply the aeration pump starts the air-bubbling process. The aeration pump allows a large amount of oxygen to dissolve in the available volume of water. This phase is known as nitrification. Oxygenation is being done alternatively with periods of rest, when the effect of denitrification takes place.
  3. Sedimentation - Aeration is switched off allowing solids to settle on the bottom of the basin. In the upper part of the basin only the clean water remains.
  4. Discharge – The clean water in the upper part is removed from the system by means of a sump pump, and discharged. After reaching the minimum level the pump stops. At this stage the supply pump is turned on, discharging excess sludge into the first chamber.

Holiday mode

If supply is not detected in the first chamber during the water intake phase, the plant switches into the holiday mode. Aeration is done in shorter and more frequent cycles in order to keep bacteria alive. The water intake in the first chamber is reduced. Water is not discharged from the system. The plant automatically switches to normal operation once water intake in the first compartment is detected.


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CMC GROUP d.o.o.
IOC Zapolje I/10
SI-1370 Logatec

T: +386 1 759 08 00
F: +386 1 759 08 01
E: info@cmc-group.si


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