Constructed wetlands as an alternative restoration measure for shallow lakes

Abstract

This paper deals with the consequences of cultural eutrophication and unconventional solutions for shallow lake restoration. Cultural eutrophication is the primary problem that affects especially shallow lakes, due to their physical characteristics (e.g. shallow depth, lack of stratification). Palic Lake, a very shallow Pannonian lake, received treated municipal wastewaters coming from the lagoons of a wastewater treatment plant. The sewage discharge mainly increased the nutrient load to the lake in the last decades. The lake sustainability is affected by inappropriate quality of water that flows into the lake, and abundance of deposited sediment. The technology that can provide both improvement of water quality and resolution of the sediment problem is a constructed wetland, which is designed to utilise the natural processes involving wetland vegetation, soil and their associated microbial assemblages to assist in additional water treatment. The technical solution is based on three key aspects: quality and quantity of deposited sediment, enriched by nutrients; effluent quality; desired lake water quality. A designed constructed wetland can accomplish the desired water quality and gradually remediate deposited sediment.

From Laboratory Tests to the Ecoremedial System: The Importance of Microorganisms in the Recovery of PPCPs-Disturbed Ecosystems

“…Nonetheless, currently physic-chemical techniques are more common than biological techniques (Figure 1) probably due to their ease of standardization. An integrative approach of all these measures will render high efficiency removal-systems [61][62][63]. Regarding PPCPs present in waters and soils ecosystems, biological remediation (or bioremediation) could be an eco-friendly solution, since some organisms can immobilize PPCPs in their biological structures (bioadsorption and bioaccumulation) or even use them as nutrients (carbon, phosphorous, nitrogen source) or electron source.…”

Potential and Constraints of Macrophyte Manipulation for Shallow Lake Management

“…Constructed wetlands might be effective in treating nutrient pollution as well as in restoration of lake ecosystems, keeping in mind that constructed wetland systems should be carefully designed and managed [28,52,53]. The use of macrophytes in the ecological restoration and water remediation contributes to the establishment of ecological balance, due to their effectiveness in the assimilation of nutrients and its role in creating the conditions for microbial degradation of organic matter.…”

“…Water regime regulation and introduction of complex drainage measures in wider area led to significant changes: natural wetlands were drained and ecosystems were changed. Nowadays, the main water source that recharges Lake Palic is wastewater treatment plant, which discharges around 13 million m 3 of water into the lake, whose quality satisfies the EU and Serbian standards [28]. The drawback of this system is that the volume of the lake is less than the discharged volume of treated wastewater during the year; therefore, there is no dilution in lake water, and nutrient load (mass) is huge.…”

“…There are also livestock farms without appropriate collection and treatment of wastewater in the surrounding area, as well as resident weekend facilities and rural settlements. All mentioned factors affect more or less the water quality in these lakes, but it is mostly influenced by water recharge [28][29][30]. Formerly, Lake Ludas received the biggest amount of water from the northern sandy terrain, by the Keres watercourse.…”