HERVA sewage treatment plants

Recommended by the Ministry of Environment of the Czech Republic, by Hydroprojekt Praha, and approved and rated as the first class quality by the State Inspecting Institute Brno. Certified according to EU standards

The plants enable unobjectionable liquidation of sewage water with fecal solids directly on the sources of pollution (septic tank, cesspool):

The treatment plants are designed in three basic sizes for minor sources of contamination. The UH-1,5 version processes 1.500 litres per day, the smaller UH-1 version processes 1.000 litres per day, and the UH-0,5 version processes 500 litres per day.
Cesspools or septic tanks serve as the first mechanical step of cleaning treatment and, at the same time, they represent accumulation space to equalize the quantitative and qualitative disproportion of the inflow.
The recovered water utilizes a gravity chute as an outlet through a gutter, drainage or a soaking area. The most convenient way to utilize recovered water is its double use either for watering or for garden irrigation. HERVA STP saves your money for empty of septic tanks.

The stabilised sludge enables utilization for preparation of compost or directly for fertilizing of flower beds without further need of additional use of solid power fertilizers.
The depth of the pits is not crucial - the patented design of the transporting equipment enables the installation for any depth.

The sewage treatment plants are located in the ground level, directly over the aperture, usually 500 x 500 mm of the existing pit without having to perform any building adjustments.
In case of requirement to treat a more considerable quantity of sewage water, different combinations of the equipment can be effected. Maximum combination of 3 x UH-1,5 models (max. total capacity of up to 4.5 m3/day)

Within the framework of complex service, we deliver a corresponding plastic septic tank. It is delivered without a cover because of the possibility of having it located in different depths. To cover the tank, it is possible to use concrete ceiling panels. Effective cubic volume is 4 ; 6 ; 8 m3. Upon request and after prior consultation, we can also deliver a non-standard version.
Note: STP may be installed in any kind of leak-proof reservoirs (cesspool, septic tank)!
The equipment is totally self-enclosed, and works in an aerobic level of purification, so that it does not produce any disagreeable odours. Assuming that the sewer intake will be ventilated above the level of the top floor of the building, it will be sufficient to have a 1 m wide protective band between the sewage treatment plant and the surrounding residential buildings. The actual effect of the sewage treatment plant is increased by the effect of the mechanical equipment placed in front of it (cesspool, septic tank). It can reach up to 30% BSK5 and 50% NL.

According to performed analyses, the decrease in the bacteria content is very significant to the sewage treatment plant, and reaches:

for psychrophilic and mezzophilic bacteria - by 2 orders
for coliform bacteria - by 2 orders
for excrementitious coliform bacteria - by 1-2 orders
for enterococci - by 1 order

The supplementary tank for watering decreases the hygienically significant bacteria groups by an additional one order.
The sludge accumulated on the bottom of the sewage treatment plant is removed at intervals depending on the surcharge of the sewage treatment plant - approximately within 21 days.
It is recommended to use it in compost or to return it into the sediment area of the septic tank.
Once a year it is necessary to provide total removing of the sludge after the whole volume of the sewage treatment was flown out.

advantages of the sewage treatment plant

suggested treatment technology

The HERVA STPs are to be used as secondary treatment plants. These plants may be used only for cleaning domestic wastewater. The units have the daily capacity from 500 litres (approx. 110 UK gallons) up to 4.500 litres (approx. 990 UK gallons), depending on the type of treated household wastewater. This volume corresponds to a household of about twelve people. The STP works on the principle of rotating bio-disks in a tank which has a sedimentation section on its bottom. Prior to the actual treatment process, a mechanical pre-treatment process takes place, either in a settling pit or a septic tank.

The sludge, generated by the treatment process, may be disposed of during maintenance.

description of the sewage treatment plants’ functions

Mechanically treated wastewater is drawn out of the septic tank with a transportation mechanism into the biozone which contains slowly rotating bio-disks. The actual treatment process is provided by a biomass of micro-organisms. Some of them build a film on the bio-disks while others float freely in the biozone. The energy necessary for the biomass to work is gained from the wastewater. The oxygen necessary for the biomass to “breathe” is generated by the rotation of the bio-disks.
The wastewater is subsequently released, through an overflow, from biozone 1 to biozone 2, in which the wastewater flows constantly over a rotating drum-disk for further oxidisation in synchronisation with
the bio-disks. This provides intensive aeration, aerobic stabilisation, and additional treatment of wastewater.
The sludge, which is formed mainly in the biomass, is separated from the wastewater in the sedimentation section, which is a conical-shaped space in the lower part of the tank. The sludge is regularly and automatically removed from this space by a programmed sludge pump at certain intervals.
The treated wastewater is released from the treatment tank through a tilted overflow opposite the wastewater influx. The treated water may be then released into the ground or use for watering or garden irrigation (if allowed by the local legislation).