WASTEWATER TREATMENT PLANT in Zabala, Covasna county

Zabala is a village in Covasna County.

Input parameters that were the basis for sizing and choosing the solution:

  • Q h max = 48 m3/h
  • Q day average= 480 m3/day
  • Q h min = 6 m3/h
  • Q day max = 576 m3/day
  • The quality parameters of the wastewater entering into the treatment plant that were taken into consideration in the planning stage are in accordance with the Norm NTPA 002/2005 (“Norms regarding the wastewater discharge in the sewerage networks of the municipalyties and directly in the treatment plants”) .
  • The Wastewater Treatment Plant meets the requirements of the European Norms and the National Norms (NTPA 001/2005) on the quality of treated water to be discharged into the natural emissary.

The wastewater treatment plant for a flow of 480 m3 / day aims to purify the wastewater collected by the sewerage network of Zabala, Covasna County.

The investment in a wastewater treatment plant from the households of Zabala, Covasna County has become a particularly important objective for the development of the infrastructure in the village, taking into account the existence of a centralized system of water supply and because the vast majority of households have sanitary facilities and bathrooms.

Domestic wastewater evacuation is carried out in an uncontrolled way, without any viable solutions for transport, treatment and disposal, with no sewerage network and treatment station. Under these conditions, domestic waste water was evacuated into sewage wells, septic tanks or directly into drains and hence infiltrated into the groundwater or other surface emissaries, affecting their quality and increasing the degree of pollution.

For the sizing of technological objects within the proposed treatment plant, 4000 inhabitants were considered for which an average flow rate of 480 m3 / day and a maximum flow rate of 576 m3 / day were calculated.

• Pumping station
• Automatic screening installation
• Fats separator
• Homogenizing Tank
• Mechanical-biological treatment
• Ultrafiltration membrane module
• Sludge processing equipment
• Container for personnel

The water treatment line consists of a mechanical separation treatment for the removal of coarse, sands and fats, followed by a biological activated sludge treatment for the reduction of nitrogen, phosphorus and CCO compounds, and a final ultrafiltration, retaining viruses with sizes greater than 0.04 microns.

The sludge resulting from biological processes is introduced into a bag-type dewatering facility. The sewage treatment plant is provided with a general by-pass.

Tratamentele si procesele ce se realizeaza in STATIA DE EPURARE sunt:

  • MECHANICAL TREATMENT: It has the purpose of separating solids (including degritt) with an automatic screen and the retention of fats. Remaining solids will be collected into a bin and will be evacuated from the enclosure periodically. After screening, the water gets into a fat separator and then into the homogenization tank.
  • BIOLOGICAL TREATMENT: Biological treatment is carried out to reduce the water contaminants to the allowed values, regulated by NTPA 001/2005. The effluent cleaned by most suspended solids passes into activated sludge biological tanks (anoxic tank and aerobic tank) where the biological sludge by means of air injection proliferates microorganisms that biodegrade organic matter such as the residue of organic solids dissolved in water.
  • ULTRAFILTRATION: It has a role in separating activated sludge from the treated water. Ultrafiltration is performed under the pressure of the water on the membrane module from the outside to the inside. Ultrafiltration of the effluent is possible due to the membrane pores size of 0.04μ. The treated effluent will be free of suspended solids, which even removes certain types of viruses without requiring final disinfection by chlorination or UV sterilization.
  • SLUDGE PROCESSING: The sludge retained after the biological treatment is introduced by the sludge pump into the bag filter of the dewatering unit. Dehydrated sludge will be stored on a platform from where it will be periodically evacuated.