Construction commenced in October 2010 and was completed by April 2011. The wastewater treatment plant consists of a settling tank for the pre-treatment and the planted soilfilter for the biological step. The operation and maintenance costs are highly dependent on the local cost of energy and staff. The required time and energy supply are listed here:
- Time needed for operation and maintenance: 1.5 h/week (80 h/yr)
- Energy supply for the pumps: 2 kWh/d (750 kWh/yr)
- Sludge disposal from the pre-treatment step: 36 m³/yr
The most time-consuming activity was obtaining the necessary permits for construction and operation of the constructed wetland. Familiarising the Bulgarian authorities with this new technology also proved time-consuming. Developers should also be aware that unforeseen problems are likely to arise during construction. This project, for example, experienced difficulties in construction due to the presence many underground cables and pipes in the yard of the Home, which had not been mentioned in previous documentation. The construction company first had to determine the location of these pipes and wires, and then modify their plans to avoid damaging them. This was a time-consuming challenge. It is often useful to use materials that are available in the region, such as the coarse sand and gravel. In some regions, pre-fabricated shafts made of reinforced concrete for the pre-treatment step are available. A cost comparison is recommended to check if the pre-fabricated parts are cheaper than constructing the shaft with reinforced concrete on-site. Plastic tanks can also be used. In the case of Vidrare, the construction on-site with reinforced concrete was the cheapest option. During construction, it was necessary to visit the site regularly, ideally daily, to check on the progress and quality of the construction. Crucial installations, e.g. the welding of the liner at the outlet of the filter, need to be inspected. Although the technology of the constructed wetland is relatively simple, a number of operational and maintenance tasks are needed to ensure the proper performance of the plant. It was emphasized that the maintenance of the wetland has to be done on a yearly basis. The involvement of local community was made from the beginning of the project and was a pre-condition of the successful implementation.