Author/Editor		Vrhovšek, D; Bulc, T
Title		Biljni uređaj za sekundarno pročišćavanje otpadne vode
Translated title		The construced wetland for secondary waste water treatment
Type		članek
Source		Hrvat vode
Vol. and No.		Letnik 3, št. 13
Publication year		1995
Volume		str. 357-62
Language		cro
Abstract		In 1989, a reed bed system was built at the central waste water treatment plant for a secondary treatment in Ajdovščina in the south-western part of Slovenia. This was one of the first waste water treatment plant of this kind buit in Slovenia. The constructed weetland consists of the bed where water seeps in the horizontal direction below the substrate surface. The substrate is a mixture of gravel, sand and soil planted with Phragmites australis. This paper describes the construction of the experimental reed bed system and the importance of both, the system design and hydrology in determining treatment performance and maximising waste water -root zone contact. It also discusses the planting and the growth of the Phragmites australis, the problem of weed control, the importance of a slope of the bed, the type of substratum and nutrient removal efficiensis. The effectivenessof of purification efficiency of the constructed wetland have been studied by monitoring physical, chemical and micro biological parameters. We have consistently found significant reduction in COD and BOD5 levels (75 - 95%), ammonia (67%), nitrite (41 - 75%), orthophosphate (54%), capability to balance the pH levels and to reduce the presence of faecal indicators, while concentracions for suspended solinds and nitrate increased in the effluent. The selection of plants used in the constructed wetland proved well suited for selected application since Phragmites australis exhibit consistent high productivity levels. The results show no significant drop in the effectiveness during winter periods. Further expansion of sconstructed wetlands usage is viable through appropriate assortment of plants and some modification of wetlands desing. They are simple in concept, inexpensive to construct and they operate without electrical power. Therefore, they are effective and economical solution to a growing probelm of environmental pollution.
Descriptors		WATER PURIFICATION PLANTS