WETLANDS, CONTRUCTED WETLANDS AND THEIR'S · PDF fileConstructed wetlands, ... Wetlands, Contructed Wetlands and ... Proceedings of 7th International Conference on Wetland Systems

FACTA UNIVERSITATIS Series: Architecture and Civil Engineering Vol. 7, No 1, 2009, pp. 65 - 82 DOI: 10.2298/FUACE0901065N

WETLANDS, CONTRUCTED WETLANDS AND THEIR'S ROLE IN WASTEWATER TREATMENT WITH PRINCIPLES AND

EXAMPLES OF USING IT IN SERBIA

UDC 628.315+828.35(497.11)(045)

Vladimir Nikolić1, Dragan Milićević2, Slobodan Milenković2

1Erasmus Mundus Stipendist, Euroaquae • E-mail: [email protected] 2University of Nis, The Faculty of Civil Engineering and Architecture, Serbia

Abstract. Wetlands protection programs, as a relative new approach in surface water and ground-water protection The types of Wetlands, their's mechanism of removal nutrients and other pollutants from water are shown in this work paper. Wetland restoration, the renewal of natural and historical wetlands that have been lost or degraded, is a growing activity. Constructed wetlands, as treatment systems that use natural processes, are very adequate and highly efficient, low cost way in wastewater treatment for small communities, point pollution sources, depending, of course on conditions and adequate land spaces near those places. Some examples from Serbia of this way and approach are shown.

Key words: Waste water treatment, Wetlands, Constructed wetlands, Macrobiological methods.

1. INTRODUCTION

Long regarded as Wastelands, Wetlands are now recognized as important features in the Landscape that provide numerous beneficial services for people and for fish and wildlife. Wetlands are among the most productive ecosystems in the world, comparable to rain forests and coral reefs. They provide great volumes of food that attract many animal species.

2. WHAT ARE WETLANDS?

Even though there are many different terms for description of the wetland systems, the most widely accepted definition was developed by the International Union for the Con-servation of Nature and Natural Resources (IUCN) in the Ramsar Convention, in 1980. According to this convention, wetlands were defined as "any areas of swamp, pond, peat, or water, natural or artificial, permanent or temporary, stagnant or flowing water, includ-

Received September 15, 2009

V. NIKOLIĆ, D. MILIĆEVIĆ, S. MILENKOVIĆ 66

ing estuaries and marine water, the depth of which at low tide does not exceed 6 meters." (Mitsch and Gosselink, 1993).

Wetlands, other than peat bogs, are highly productive systems and support high biodi-versity. Like other ecosystems, wetlands also perform many ecological functions. The hy-drological, biological and biogeochemical functions impart them various values (Sather and Smith, 1984). Some of the values of these wetlands given by Vymazal et. al (1998) and Denny (1997) are summarized below: water quality functions and water quality im-provements, hydrological and hydraulic functions, climatic effects, biodiversity functions, energy production, educational uses, recreational and reclamation uses.

All Wetlands – freshwater or salt – have one characteristic in common: the presence of surface or near – surface water, at least periodically. The hydrology of Wetlands is generally one of slow flows and either shallow or saturated substrates. The slow flows and shallow water depths allow sediments to settle as the water passes through the Wetland. The slow flow also provides prolonged contact time between the water and the surface within the Wetland. The complex mass of organic and inorganic materials and the diverse opportunities for gas/water interchanges foster a diverse community of microorganisms that break down or transform a wide variety of substances.

Wetlands perform many functions that are beneficial to both humans and wildlife. One of the most important is water filtration. As water flows through a Wetland, it slows down and many of the suspended solids become trapped by vegetation and settled out. Other pollutants are transformed to less soluble forms taken up by plants or become inactive. Wetland plants also foster the necessary conditions for microorganisms to live there. Through a series of complex processes, these microorganisms also transform and remove pollutants from the water. Nutrients, such as nitrogen and phosphorus, are deposited into wetlands from storm water runoff, from areas where fertilizers or manure have been ap-plied and from leaking septic fields. These excess nutrients are often absorbed by Wet-land soils and taken up by the plants and microorganisms. For example, Wetland mi-crobes can convert organic nitrogen into useable, inorganic forms (NO3 and NH4) that are necessary for plant growth and into the gasses that escape to the atmosphere.

Wetland processes: water retains more days sedimentation it’s cleaned by plants and microorganisms

reduction of nitrogen, phosphorus substances, heavy metals and other toxic compounds and bacteria

plants under the surface of device provide oxygen

an area rich with oxygen is created around the roots

cleaning is effective

Fig. 1 How wetlands work

Wetlands, Contructed Wetlands and their's Role in Wastewater Treatment... 67

Wetlands are one of the most valuable and fragile components of a watershed, but for many years they were filled and drained for agriculture and development. Now we are learning that wetlands are crucial to the health of our waters and wildlife. Wetland resto-ration, the renewal of natural and historical wetlands that have been lost or degraded, is a growing activity. It can improve water quality and wildlife habitat across the world. When high concentration of nutrients enter water as a result of human activities, often occurs Hypoxia. Hypoxia is the condition in which dissolved oxygen is below the level necessary to sustain most animal life. For many members of aquatic community, hypoxia is like drowning, because life giving dissolved oxygen levels in a body of water drop much lower than normal.

There is growing interest and expertise in the field of Wetland restoration. This trend is a good news for hypoxia affected waters since some Wetlands can significantly reduce the amount of nutrients reaching our inland and coastal waters. Restoring the lost and de-graded Wetlands to their natural state is essential to ensure the health of watersheds. Restoration is a complex process that requires expertise, resources, and commitment from many different stakeholders. All restoration projects require planning, implementation, monitoring and management. Many projects require a team with expertise in ecology, hy-drology, engineering, and environmental planning. Getting local experts and community involved gives the project local ownership, which is important for restoration success.

Nutrient removals from several specific natural wetlands projects are presented in Table 1.

Table 1. Nutrient removals from several specific natural wetlands projects

4. CONSTRUCTED WETLANDS FOR WASTEWATER TREATMENT

As a result of the exponentially increasing demands of human expansion and resource exploitation, it has been recognized that natural wetland ecosystems cannot always func-tion efficiently for desired objectives and stringent water quality standards. These and many other factors have led to the rapid development of "constructed wetlands" for wastewater treatment (Wetzel, 1993).

Because natural systems can improve water quality and filter pollutants from water that flows through on its way to receiving lakes, streams and oceans, engineers and scien-


tists construct system that replicate the functions of natural wetlands. So, Constructed wetland treatment systems are engineered systems that have been designed and con-structed to utilize the natural processes involving wetland vegetation, soils, and their as-sociated microbial assemblages to assist in treating wastewater. They are designed to take advantage of many of the processes that occur in natural wetlands, but do so within a more controlled environment. Synonymous terms to constructed include manmade, engi-neered or artificial wetlands.

What Constructed Wetlands can provide: water quality improvement flood storage and the desynchronization of storm rainfall and surface runoff cycling of nutrients and other materials habitat for fish and wildlife passive recreation, such as bird watching and photography active recreation, such as hunting education and research aesthetics and landscape enhancement

When properly designed, constructed wetlands offer a number of advantages, includ-ing low cost, simplicity of operation, and effective removal of BOD5 and TSS (table 2). When sized adequately, constructed wetlands are also tolerant of fluctuating flows and variable water quality.

Constructed wetland treatment is constrained by a number of limitations, including relatively large land requirements and a degree of uncertainty not found in more conven-tional approaches (table. 2).

Table 2. Advantages and limitations of constructed wetland treatment of domestic wastewater

Advantages Limitations

Excellent removal of BOD5 and TSS Good removal of nutrients, depending on system design Ability to handle daily or seasonally variable loads Low energy and maintenance requirements Simplicity of operation

Variable treatment efficiencies due to the effects of season and weather Uncertainty as to treatment effectiveness under all conditions Sensitivity to high ammonia levels Larger land area requirement than for conventional treatment Potential for mosquito production

The use of constructed wetlands for sewage treatment at different levels is commonly well known. However, they have also been applied for the treatment purpose of different types of wastewater. Some of these applications include treatment of wastewater origi-nating from several industries, agricultural activities, landfills, surface runoff, acid mine drainage, sludge dewatering, etc. In order to understand the current trend for constructed wetlands, the current literature has been reviewed and classified according to the type of treated wastewater (Table 3).


Table 3. Distribution and percentage of the studies on constructed wetlands used for several purposes (1994-2000)

Type of Treated Wastewater in Constructed Wetlands Number of Studies

Percentage (%)

Municipal 106 31.5 Leachate 12 3.6 Acid Mine Drainage 8 2.4 Surface Runoff 24 8.1 Sludge Dewatering 5 1.5 Industrial 35 10.5 Restoration and Rehabilitation, Prevention of Eutrophication 42 12.5 Agro-Industrial 38 11.3 Reviews, Suggestions, Design Criteria 64 19.1

References: Water Science and Technology, Vol: 35(5) 1997 and Vol: 40(3) 1999; Proceedings of 7th International Conference on Wetland Systems for Water Pollution Control, Florida, 2000.

5. CLASSIFICATION OF CONSTRUCTED WETLANDS

Constructed wetlands could be classified according to the various parameters but two most important criteria are water flow regime (surface and sub-surface) and the type of macrophytic growth (Fig. 2). Different hybrid or combined systems in order to exploit the specific advantages of the different systems.

Constructedwetlands

Sub-surface flowSurface flowEmergent plants

Submerged plants

Free floating plants

Floating-leaved plants

Horizontal Vertical

Hybrid systems

Downflow

Upflow

Tidal Fig. 2 Basic types of Constructed Wetlands

Constructed wetlands with surface flow (= free water surface, FWS) consist of basins or channels, with soil or another suitable medium to support the rooted vegetation (if pre-sent) and water at a low flow velocity, and presence of the plant stalks and litter regulate water flow and, especially in long, narrow channels, ensure plug-flow conditions (Reed et al., 1988). One of their primary design purposes is to contact wastewater with reactive biological surfaces (Kadlec and Knight, 1996). The FWS CWs can be classified accord-ing to the type of macrophytes (Fig. 2).


Fig. 3 A surface flow wetland consists of a shallow basin, soil or other meddium to

support the roots of vegetation, and a water control structure that maintains a shallow depth of water.

A subsurface flow (= subsurface flow system, SFS) constructed wetland consists of a sealed basin with a porous substrate of rock or gravel. The water level is designed to re-main below the top of the substrate. Constructed wetlands with sub-surface flow may be classified according to the direction of flow into horizontal (HF or SSF-H) and vertical (VF or SSF-V) (Fig. 2).

Fig. 4 Constructed Wetlands with rooted vegetation and horizontal (left) or vertical

flow of the water (right)

Various types of constructed wetlands may be combined in order to achieve higher treatment effect, especially for nitrogen. There has been a growing demand in achieving fully-nitrified effluents but secondary treatment HF systems cannot do this because of their limited oxygen transfer capacity (Cooper et al., 1996; Vymazal et al., 1998a). VF systems have a much greater oxygen transport capacity and, therefore, provide much better condi-tions for nitrification.

HORIZONTALFLOW

VERTICALFLOW

OUTFLOW

INFLOW

REC

YCLE

FO

R D

EN

ITR

IFIC

ATIO

N

(IF N

EED

ED)

Fig. 5 Schematic arrangement of the HF-VF hybrid system

according to Brix and Johansen

Hybrid systems used to comprise most frequently VF and HF systems arranged in a staged manner, however, all types of constructed wetlands could be combined. In hybrid systems, the advantages of various systems can be combined to complement each other. It is possible to produce an effluent low in BOD, which is fully-nitrified and partly denitri-fied and hence has much lower total-N concentrations (Cooper 1999, 2001).


6. CONSTRUCTED WETLANDS DESIGNING

Constructed wetlands are ecological systems that combine physical, chemical, and biological processes in an engineered and managed system. Successful construction and operation of an ecological system for wastewater treatment requires a basic knowledge and understanding of the components and the interrelationships that compose the system. A Constructed Wetland consists of a properly designed basin that contains water, a sub-strate, and, most commonly, vascular plants. Other important components of Wetlands, such as the communities of microbes and aquatic invertebrates, develop naturally.

Suggestions for creating an effective constructed wetland are given in table 4. Since the objective of using a constructed wetland is to simplify the handling of wastewater, the system should be made as easy to operate as possible while ensuring reliable treatment. Building a slightly larger system may be more expensive to construct but may be more reliable and less costly to operate than a smaller system. Attention to several factors will help to ensure successful wetland treatment:

Adequate pre-treatment. Pollutant loads in raw wastewater can exceed the ability of a wetland to treat or assimilate them. Wetland treatment is suitable for waters that have received primary or secondary treatment. Adequate retention time. A wetland treats wastewater through a number of biologi-cal (largely microbial), physical, and chemical processes. The water must remain in the wetland long enough for biological and chemical transformations to take place and for sedimentation and deposition to occur. The wetland must be built large enough to provide the necessary retention time. Supplemental water. If a constructed wetland is to remain healthy, it must remain relatively wet. Wetland plants are generally tolerant of fluctuating flows, but they cannot withstand complete drying. For this reason, either a fairly regular supply of wastewater must be assured or a supplemental source of water must be provided. Proper management. Constructed wetlands are "high management, low mainte-nance" systems. They must be actively managed if they are to perform well. "Management" means watching the wetland for signs of stress or disease and adjusting water levels or wastewater input streams accordingly. While wetlands are low maintenance systems, they are not maintenance free. For instance, distribution systems must be cleaned pe-riodically to avoid plugging and uneven distribution of flow, and valves and piping must be checked to detect and correct blockages or leaks.

The land area and engineering required to establish the correct constructed wetland arrangement is largely related to the degree of treatment required from the system in rela-tion to the social and aesthetic objectives and topography of the site available. Table 5 il-lustrates process design criteria for Free Water Surface (FWS) and Subsurface flow (SFS) constructed wetlands adapted from Reed (1992) and Knight (1992).


Table 4. Guidelines for creating constructed wetlands.

Know what you are dealing with: Wetlands must have water: Size the wetland generously: Give the plants a chance: Don't overload the wetland: Protect the wetland from toxics: Keep an eye on what is happening: Get interdisciplinary help:

Sample the wastewater Know what pre-treatment will accomplish Know the water budget An undersized wetland cannot perform well Allow time for establishment Avoid shock loadings Application rates must not exceed treatment rates Limit the toxics entering the wetland Keep herbicides out of the wetland Monitoring is needed to assure continued performance Environmental engineer Water quality specialist Plant materials specialist or biologist State agencies

Table 5. Process design criteria for constructed wetlands

Factor Typical FWS Typical SFS Detention time, d 5-14 2-7 Max BOD loading rate, kg/ha.d 80 75 Water or Substrate Depth, m 0.1-0.5 0.10-1.0 Hydraulic loading rate, mm/d 7-60 2-30 Areal Requirement, ha/m3.d 0.002-0.014 0.001-0.007 Aspect Ratio l to w 2:1 to 10:1 0.25:1 to 5:1 Mosquito Control Required Not required Harvest Frequency, yr 3-5 3-5

The constructed wetland system itself is increasingly unlikely to be a single unit but rather an integration of units, which may include reedbeds, marshes, ponds, grasslands and even for-est/shrub areas. The units may also operate as surface or subsurface filtration systems as appro-priate to optimize physico-chemical pollutant removal mechanisms and to balance aerobic and anaerobic biological degradation reactions: evapotranspiration and infiltration.

The type of the plants depends of the type of the wastewater (domestic sewage, agricultural wastewater, storm runoff...) geoposition and climatic conditions of a place where wetland is.

Vegetation selection needs to accommodate the hydraulic operations of the Wetland system and still support habitat objectives. In general, use a diversity native, locally obtained species. Native plants from existing Wetlands may be harvested provided that removal of the plants does not result in damage to the existing Wetland. Species should be chosen both for water quality and wildlife habitat functions, if that is intent of the project. The use of weedy, invasive, or non-native species should be avoided. Also we should consider the plants abili-ties to adapt to various water depths and soil and light conditions at our site.

Seeds, seedlings, entire plants, or parts of plants can be used to establish wetland vegetation. While many wetland plants produce wind-borne seeds, vegetative spread by


stolons and runners is common since seeds generally will not sprout under water. Many emergent’s have rhizomes, rootstock, or tubers, which, although they are primarily food storage organs, can generate new plants.

The plants for treatment wetlands must be able to tolerate the combination of continuous flooding and exposure to wastewater or storm water containing relatively high and often vari-able concentrations of pollutants. For wastewater treatment wetlands, the particular species se-lected are less important than establishing a dense stand of vegetation. Any species that will grow well can be chosen. For storm water wetlands, species should be chosen to mimic the communities of emergent plants of nearby natural wetlands. For both wastewater and storm water wetlands, native, local species should be used because they are adapted to the local cli-mate, soils, and surrounding plant and animal communities, and are likely to do well.

The plants that are most often used in constructed wetlands are persistent emergent plants, such as bulrashes (Sciprus), spikerush (Efeocharis), other sedges (Cyperus), rushes (Juncun), common reed (Phragrnites) and cattails (Typha).

Fig. 6 An example of plants recommendation for diferent types of wetlands

Table 6. Efficiency of the conducted treatment comparing various unitary operations used in the primary and secondary treatment processes (Metcalf, Eddy, 1999).

Purification efficiency (%) Purification process BOD KPK SS P Org-N NH3-H Primary sedimentation tank 30-40 30-40 50-65 10-20 10-20 0 Activated sludge process 80-95 80-85 80-90 10-25 15-50 8-15 Biofilter, highly efficient rock medium 65-80 60-80 60-85 8-12 15-50 8-15 Biofilter, efficient plastic medium 65-85 65-85 65-85 8-12 15-50 8-15 Biodisk 80-85 80-85 80-85 10-25 15-50 8-15 Constructed Wetlands 80-90 80-85 70-85 70-90 70-90 70-90

In terms of reduction of organic pollution a significant independence is noticeable between effluent’s organic output concentration and entering concentration in waste wa-ter. The quality of the final effluent from the systems improves with the complexity of the facility. Table 6 compares effects of waste water treatment in the classic WWT process and Constructed Wetlands, while Table 7 shows effects of treatments of typical polluters in several projects performed in USA.


Table 7. The removal efficiency of typical pollutants

7. CONFIGURATION OPTIONS FOR CONSTRUCTED WETLANDS

Various configurations are possible for the constructed wetland and for incorporating it into a treatment system (figures 7 and 8). System configuration includes length-to-width ratio (sometimes called "aspect"), compartmentalization, and the location of single or multiple discharge points. The configuration should take advantage of the natural topography of the site to minimize excavation and grading costs. While wetlands are often designed as rectan-gles, wetlands can be built in almost any shape to fit the topography of the site.

An example of synthesizing the macrobiological unit operations into the complex ones, which are cheaper in terms of investment and power consumption, at smaller ag-glomerations, especially with the seasonal summer problems, is presented in the figure 8.

StabilizationPond

ConstructedWetland

StabilizationPond

StabilizationPond

ConstructedWetland

ConstructedWetland

ConstructedWetland

SepticTanks

ConstructedWetland

ConstructedWetland

SepticTanksSepticTanks

ConstructedWetlandComminuter Imhoff

Tank

Sludge Drying Bed

ConstructedWetland

ConstructedWetlandComminuter Imhoff

Tank

Sludge Drying Bed

Comminuter ImhoffTank

Sludge Drying Bed

Fig. 7 Configuration options for constructed wetlands (from Steiner and Freeman 1989).


The scheme includes the water treatment and sludge settlement, so that they can be discharged into the environment without negative effects, that is, an environmentally clean and friendly technology is presented. Depending on the ability and care of the op-erator, the removal of suspended and putrescible matter is from 80% up to more than 95% and higher. Bacteria reduction is over 99%, so that without any risk, water can be used for irrigation in the semi-arid regions [Ignjatović L., 1995].

Fig. 8 Scheme of the human settlement waste water treatment facility [Ignjatović L., 1995]

UG – inlet structure ; ET – efficient settlement tank HB - basin for sanitary hydrophytocultures (surface flow wetland); AB - basin for sanitary aquacultures; DM – sludge digestor ; VP – vermiculture fields

7. CONSTRUCTED WETLANDS AND ENVIRONMENT

Constructed Wetlands are easily implemented in neighbouring environment. Once constructed, wetlands enhance flora and fauna, increase plants’ diversity, and present fa-vourable habitats for birds. Moreover, wetlands have negligible effects on air quality since polluted water circulates underground, preventing odours appearance.

Constructed wetlands need to be arranged to meet hydrological and wastewater quality requirements, but also to integrate effectively into the surrounding existing landscape. The arrangement of wetland, basin and high flow bypass should be designed early in the con-cept design phase, to ensure that amenity of open space is enhanced.


Fig. 9 Typical Landscape Treatments to Constructed Wetlands in Open Space Areas

The final shape of a wetland should provide landscape opportunities to create alter-nate useable spaces/recreation areas. Often different shapes to wetland edges can make pathway connections through and around these recreation areas more convenient and en-hances the community perception of constructed wetlands. Pathways and bridges across planted earth bunds can be the best way of getting across or around wetlands. The materi-als on the bridge and pathways are important to be low maintenance and do not impede hydrological flows. Ease of access to the inlet basin for sediment and trash removal is also important to consider.

Fig. 10. Example Relationship Between High Flow Bypass, Wetland

and Basin and the Creation of Open Space


8. EXAMPLES OF CONSTRUCTED WETLAND

An example of a Constructed Wetland designed for individual residential object waste water purification process is presented in figure 11.

Fig. 11 Schematic view of Constructed Wetland: Single Use (Base and Longitudinal Section)

Fig. 12 Layout of Proposed Wetland System


As part of a residential development in Pimpama on the Gold Coast, storm water run-off is to be delivered to a constructed wetland for water quality treatment. An illustration of the site and proposed layout of the wetland is shown in Figure 12. This example de-scribes the design process for each component of the constructed wetland: inlet zone (in-cluding the bypass weir), macrophyte zone, macrophyte zone outlet and high flow bypass channel.

9. CONSTRUCTED WETLANDS IN SERBIА

Intensive research in the macrobiological methods began in the 80’s in the world, and almost simultaneously at the Faculty of Civil Engineering and Architecture of Nis, leeding by. Proff. L. Ignjatović. The initial results were obtained in the 1975-1979 period and in the course of 80’s. Numerous macrobiological unit operations (floating macrophytea, constructed wetlands...) in cooperation with the eminent experts from the USA, were tested as laboratory models and then translated to the level of macro mode. They were tested in the part of the waste water treatment facilities in Sokobanja (20.000 hab. by summer) spa town and municipality situated in eastern Serbia, near Nis, 1980.

In a first phase after the "classical" treatment plant with a classic line (inlet grid, sedi-mentation, oxidation basins) Surface flow Wetlands is used like experimental part, with a plants: Eichornia Crassipes and Pistia Stratiotes macrophytaes. Sanitary fish pond was in-cluded as finishing part of Wastewater Treatment Plant end after it, Surface flow Wet-lands. The sludge was used as good habitat for earthworms (L. Rubellus) cultivating. Methane produced in digesters was planned for heating laboratory.

Fig. 13 Waste water treatment facilities in Sokobanja (Base, experimental plant with

Eichornia Crassipes and Pistia Stratiotes macrophytaes, Sanitary fish pond), 1980.


Fig. 14. Basin for floating macrophytes with water lettuce (Pistia Stratiotes L.) and water

hyacinth (Eichornia Crassipes M.)

Fig. 15 Map of the basin - sanitary fish-pond in Sokobanja [Ignjatović L., 1995] and the

appearance of the basin.

Wastewater treatment plant Sokobanja is designed and constructed in order to that all natural sources and processes are used in function to cleaning wastewater, domestic and low concentrated industrial. The best data of efficiency of such WWT is that in case of inlet con-centration of DO of 0 (zero) mg/l, on the outlet concentration of DO was 8-9 mg/l.

In second phase Subsurface flow Wetlands (horizontal flow) second line of Wastewa-ter Treatment Plant, worked as a probe, with native plants, from this area (Rogoz, Serb - Thypa latifolia Lat., Trska, Serb. - Phragmites communalis Trin, Lat.) and was designed 1990. The wastewater comes, after high efficiancy, settlement tank, into Constructed Wetland. Now is in reconstruction.


Fig. 16 Constructed Wetland Technology Shemma

(Designed by prof. L. Ignjatović, Constructed, and Tested), 1990.

Constructed Wetland in Serbia, are also used about 2004 year in village Glozane, de-signed by "Biro Neptun" Company, and at the present this technology is having consider-able role in Wastewater treatment in Serbia, now mostly in Autonomous Province of Vo-jvodina.

Village Glozane involves Constructed Wetland of hybrid structure, containing three fields designed for 2.275 HE. Total foreseen system area is approximated on 8.271 m2, or 2,95 m2/ES. Currently only some elements of the system have been constructed and ex-ploited. Effects of purification process are presented in table 8 and 9.

Fig. 17. Constructed Wetland Glozan – Serbia


Table 8. Effects (diff. conc. influent/effluent) of such pant given by Biro Neptun

Parametar Wet Field I Wet Field II Wet Field III Tot. Reduction BOD5 70.1 28.7 0.26 99.1 TSS 91.3 2.6 2.20 91.7 P 21.2 36.1 40.20 97.5 Amoniumion 26.3 37.7 35.80 99.8 Chlorides 32.9 16.6 33.60 83.1

Table 9. Quality of treated water

Parametar II class of water quality Effluent Dissolved oxygen (mg/l) 6-8 7.6 BOD5 (mg/l) 2-4 3.8 Suspended Solids (mg/l) 10-30 19 Dry residuals (mg/l) 350-1000 942

10. CONCLUSION

Last 30 years wetlands are recognized as important features a watershed because they serve as the link between land and water resources. Wetlands protection programs are most effective when coordinated with other surface and ground-water protection programs and with other resource management programs, such as flood control, water supply, pro-tection of fish and wildlife, recreation, control of storm water, and nonpoint source pollu-tion. Wetland restoration, the renewal of natural and historical wetlands that have been lost or degraded, is a growing activity. It can improve water quality and wildlife habitat across the world. Constructed wetlands are treatment systems that use natural processes and are very adequate and high-efficient, low cost way in wastewater treatment for small communities, point pollution sources, depending, of course on conditions and adequate land spaces near those places. That's way that approach of improving water quality is in trend to be more and more used.

REFERENCES 1. Free Water Surface Wetlands for Wastewater Treatment: A Technology assessment.pdf – EPA document 2. Constructed Wetlands Treatment of Municipal Wastewaters, U.S. Environmental Protection Agency

Manual EPA/625/R-99/010, September 2000., http://www.epa.gov/ORD/NRMRL 3. Vymazal J., Kröpfelová L.: Wastewater Treatment in Constructed Wetlands with Horizontal Sub-Surface

Flow, Environmental pollution, Volume 14, Springer Science + Business Media B.V., 2008. 4. Wood A.: Constructed Wetlands in Water Pollution Control: Fundamentals to Their Understanding, Wat.

Sci. Tech, Vol. 32., No. 3., pp. 21-29, 1995. 5. Our Living City - Gold Coast Planning Scheme Policies, Policy 11: Land Development Guidelines, Sec-

tion 13 - Water Sensitive Urban Design (WSUD) Guidelines, June 2007. 6. Korkusuz E. A.: Domestic Wastewater Treatment in Pilot-Scale Constructed Wetlands Implemented in

The Middle East Technical Univiersity, PhD Thesis, The Graduate School of Natural and Applied Sci-ences of The Middle East Technical University, September 2004.

7. L. Ignjatović: Makrobiološke metode u preradi otpadnih voda, Vodič kroz jedinične operacije, Eco - Tech, Beograd, Serbia,1995.


8. Milićević D.: Macrobiological methods in wastewater treatment - new approach in system. modeling, Facta Universitatis, 1996, The Faculty of Civil Engineering and Architecture of the University of Nis, Serbia and Montegro

9. S. Milenković, D. Milićević, V. Nikolić: Application of macrobiological methods in the settlement waste water treatment and exploitation of its energy and resource potential, Conference on Water Observation and Information System for Decision Support, Balwois, Ohrid 23-26 may 2006, Macedonia, Abstracts p.192.

10. Griessler Bulc T. G., Vrhovšek D.: Rastlinske čistilne naprave za čiščenje odpadnih voda, Letna konfer-enca Katedre za Biotehnologijo: Pomen biotehnologije in mikrobiologije za prihodnost: voda, Ljubljana, 18-19.1.2007.

11. Vukelić S.: Constructed wetlands - kao mogućnost u prečišćavanju otpadnih voda manjih naseljenih me-sta, 28. Stručno-naučni skup sa međunarodnim učešćem Vodovod i kanalizacija ’07, Savez inženjera i tehničara Srbije, Tara 16-19. oktobar 2007., Zbornik radova pp. 161-166

12. Sokobanja, potrojenje za preradu otpadnih voda Dokumentacioni Arhiv, PS EKO 2, dr Lazar Ignjatović, Gradjevinski fakultet, Nis, Serbia 1980

13. http://www.epa.gov/owow/wetlands 14. http://www.epa.gov/owow/wetlands /watersheds/cwetlands.html 15. http://www.limnos.si.

VETLANDI, KONSTRUISANI VETLANDI I NJIHOVA ULOGA U PREČIŠĆAVANJU OTPADNIH VODA SA PRINCIPIMA I

PRIMERI NJIHOVOG KORIŠĆENJA U SRBIJI

Vladimir Nikolić, Dragan Milićević, Slobodan Milenković

Program zaštite vetlanda, kao relativno novi pristup zaštiti površinskih i podzemnih voda, vrste vetlanda i mehanizam ukljanjanja nutrijenata i drugih zagadjujućih materija su prikazani u ovom radu. Obnavaljanje i već degradiranih vetlanda, u naporu za poboljšanje kvaliteta površinskih voda je danas sve aktuelnija aktivnost u svetu. Veštački vetlandi, kao sistemi za prečišćavanje voda koji koriste prirodne procese su vrlo primereni i visoko efikasni, male cene prerade otpadnih voda naselja, koncentrisanih zagađivača što sve, naravno, zavisi od uslova i raspoloživog prostora za izgradnju. Dato je nekoliko primera ovakvog pristupa prečišćavanju voda u Srbiji.

Ključne reči: biološke zavese, veštačke biološke zavese i njihova uloga u prečišćavanju otpadnih voda; principi i primeri primene u Srbiji

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WETLANDS, CONTRUCTED WETLANDS AND THEIR'S · PDF fileConstructed wetlands, ... Wetlands, Contructed Wetlands and ... Proceedings of 7th International Conference on Wetland Systems