Upgrade of the Treatment Plant Domžale - Kamnik
The upgrade project of the CTP Domžale - Kamnik includes an upgrade of the CTP Domžale - Kamnik to the tertiary biological treatment with a sequential batch reactor technology - SBR and a construction of the input object with the adoption of the cesspool sludge.
In accordance with the Decree on the emission of substances in waste water discharges from municipal wastewater treatment plants (Official Gazette of RS, Nos. 45/2007, 63/2009, 105/2010), the area of settlement Domžale - Kamnik and the CTP Domžale - Kamnik must provide tertiary treatment until August 22, 2016, which means an additional removal of nitrogen and phosphorus. The cleaning effect of nitrogen and phosphorus compounds from waste water will be unsatisfactory under the new legislation and would - due to surplus of the concentrations - be an excessive burden to the environment.
By upgrading the biological levels of water lines the cleaning effect will be improved and, thus, the quality of the effluent, which will significantly contribute to the reduction of pollution of the river in Kamniška Bistrica will be improved, and be marked with a better ecological status. The CTP will also adopt and clean larger volumes of wastewater when rainfall from the mixed sewerage network. A safe operation within statutory limits and standards will be ensured and the excessive pollution of the environment reduced.
Subject of the project is also to build an entrance building and sludge reception. This will increase operational safety, allow a more efficient elimination of sand and larger particles, arrange adequate hydraulic flow to the CTP, increase the quantities of coarse purification of rainwater and reduce air emissions.
Intentions and objectives
The upgrade of the CTP Domžale - Kamnik has environmental importance, the objectives of which are:
- to solve the problem of wastewater treatment in the region (an area of 149,000 PE) for the 30-year period,
- to ensure safe operation within statutory limits and standards and
- to ensure a reduction in environmental pollution.
Technical solutions
Tertiary biological purification step (SBR)
An upgrade of the existing plants includes a construction of new facilities of the biological level of water lines, bins and excess sludge thickeners, a hardware pre-condensation of excess sludge and the disintegration of excess sludge before pumping into the digester, and the reduction of nitrogen in mud.
Subject to the following technological upgrades subassemblies and facilities:
- the effluent from the primary sedimentation tanks,
- distributor of water,
- sequential pools,
- object of the effluent measurement location,
- excess sludge thickener,
- hardware pre-condensation of mud,
- bins of pre-condensated mud,
- disintegration sludge,
- precipitation of phosphorus,
- a compressor station (existing facility),
- feeding an external source of carbon,
- mud pumping,
- air biofilter,
- a new substation and
- a reduction of nitrogen in mud.
Boarding facility
Due to the increased demands of operational security, more effective elimination of sand and larger particles, achieving a greater flow through the mechanical pre-cleaning and replacement of some worn-out equipment a reconstruction of the existing entrance building is estimated. At the same time a construction of the facility for various slurries, which are being collected in two separate pools and drawn in two different locations - in the digester or aerated sand trap and trap fat is planned.
The existing entry facility, which includes the discharging of the rain influx and a rough rake with a conveyor system for the ejection of culled rakes’ waste into the containers, will be completely demolished and a new entrance building as a covered single-story structure will be built. The following technological subassemblies will be carried out in the facility: relief valve I., coarse rakes mounted onto the bypass with the discharge into the system of the spiral conveyor, rock catcher with a hydraulic device to extract the penstock precipitated sand/stones in a container for sand with the size of 5 m3, two coarse and fine electric rakes in double kinetic with associated transport equipment for the evacuation on the rakes culled waste into three containers (AC charging), and a water flow meter. All containers are installed in a closed facility.
Access to the facility and all the three containers can be found on the north and south side of the facility. These go through electrically charged revolving doors, which are designed to allow smooth passage for and loading of the collection containers. For free access of goods vehicles in the input object will be the northern edge of the road at the entrance pumping shifted slightly to the pumping facility. An access road will be built on the north side of the plot, which will enable circular traffic through the facility, mainly for the removal of containers. This road will also enable a driveway for vehicles that transport waste water to the facility. After the completion of the reconstruction of the entrance building the existing fine rakes mounted on the sand catcher will be removed. The biofilter will be located in the northern part of the object.
In the context of the reconstruction of the entrance building the existing relief valve at the inlet pumping station will be reconstructed. The length of the discharging overflow will increase. Before the start of the reconstruction of the entrance building the inflow of water to the CTP into an existing recess will be temporarily diverted. From here the water will shift to the input pumping station.
Sludge receiving facility will be built out as a two-floor structure, with two underground storage tanks and a machine house and a ground floor in which fine electromotive rake with a conveyor system will be installed. Part of the ground floor is fitted with electric switchgear blocks and a place with a container for waste collection. The estimated reconstruction will also reduce air emissions.
