Category / type: water recycling plant, non-potable use.
Application: toilet flushing, garden watering, car wash, laundry,domestic, commercial, public.
Flow rate: from 600 up to 10.00 litres per day(packaged and/or site assembled) and more than 50 tailor-made.
Normative references and guarantees: DIN 4046:1983-09 water-supply, terms.
Technology: membrane, ultrafiltration, biological.
Target: drinking water resource protection, dual water networks.
The most complete recycling level is the black or sewage water treatment. It is a fairly extensively used approach, where cyclical droughts prioritize all forms of water conservation, even thought currently it is much less popular in Europe.
Usually wastewater, or blackwater, coming from civil metabolism, are treated by classic biological plants composed by some pre treatments, a biological reactor and, if requested, by a tertiary phase. If the effluent need to be recycled the all plant must be designed to guarantees the best performance in all steps. Although the plant configuration should the same for all black-water treated, but the technology installed change and increase in efficiency when effluent must be recycled.
Compared to greywater recycling systems, the black-water one is often more practical because most plumbing systems don’t separate greywater streams (e.g. showers, basins).
Black water recycling plants produce water for non-potable use as irrigation or flushing toilets.
How It Works
These systems can suit residential homes, small communities, resorts, maritime applications, high rise buildings, office blocks, schools, etc.
In a blackwater recycling system, all household (or assimilable) water are often collected into a primary treatment using gravity (settling, screening, etc.). Then blackwater is diverted into a secondary treatment tank as an activated sludge plant or other kind of biological reactors and, at last, to a tertiary treatment.
Further treatments as settling, ultrafiltration, membrane (as MBR plants), reverse-osmosis membranes, etc. improve effluent quality according to standard’s requirements.
Treated water is always stored for reuse after a disinfection phase. This phase is cxarried out by the mean of chlorine (if water is not used for irrigation) or Ultraviolet Rays sterilization, depending on local health regulations and on customer requirements.
In order to recycle water, it’s necessary to have two separate hydraulic circuits that supply waters into buildings. So for all new buildings, but also for restored ones, it’s strongly recommended to take into account a dual water networks during construction phases.
Operation and maintenance
Blackwater recycling system often adopts biological treatment and it requires all operations of maintenance as normally used for wastewater treatment plants.
Settled sludge will be periodically removed by skilled personnel of authorized companies.
This system type generally may require servicing by the installation company every few month, and periodical analysis to avoid health risks caused by pathogens not correctly removed.
The use of environmentally friendly products is warmly encourage in order to avoid any problems to the system caused by antibacterial soaps.
Minimize human contact with recycled water is also recommended. It could potentially contain pathogens. Therefore some system should be designed for the water to soak into the ground and not be available for people or animals to drink.
Regular maintenance is absolutely necessary for the proper functioning of the system (see manual of use and maintenance of product for any detailed recommendation).
EN 1085:2007 Wastewater treatment. Vocabulary – It defines terms for wastewater treatment. The aim of this European Standard is to establish a standardized terminology in the field of wastewater treatment in the three official languages of CEN: German, English and French.
There are national and local regulations for recovery water system.
Features and benefits
Wastewater recycling plant can often be retro-fitted to existing buildings or be installed in new developments without dealing with dual network sewer complexities.
This solution provides an additional source of water to keep gardens and sports fields green where regulations limited water resources available for aesthetic uses.
Water treated by standard blackwater system isn’t suitable for use on vegetable gardens and certainly not for drinking water, but it can really help in reducing the use of water for irrigation purposes.
- drinking water resource saving;
- reducing water use
- money saving;
- less strain on septic tank or treatment plant;
- plant growth;
- reclamation of otherwise wasted nutrients
- non-potable water network;
- pay attention to no drinking water (warning sign);
- electric pump or pressure system needed;
- periodic maintenance require