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Estonia

1. General Information

Overview of the current situation in Estonian water management is briefly given on the website of Ministry of Environment of Estonia www.envir.ee/67250 who is responsible for developing and implementing water management strategies and policies.

2. Specific Information

During the 1990´s after the re-establishment of independence wastewater treatment was not of the top priorities of our young republic. Therefore the majority of wastewater treatment facilities, mainly the ones treating wastewater from smaller communities (100-5000 inhabitants) that originated from Soviet Union times were neglected or left without proper maintenance. In the beginning of the first decade of the 2000´s when more stringent EU-regulations found their way into Estonian legislation, the need for wastewater treatment became more relevant.

As the fresh water resources in Estonia are sufficient there has been no urgent need for the re-use of neither treated wastewater nor rain water. Thus the main objective of wastewater treatment is according to the Water Framework Directive (2000/60/EC) to achieve good quality of water (surface water, coastal water, ground water). The latter is also adopted to Estonian environmental policy through “Environmental Strategy of Estonia up to 2030” (available only in Estonian).

Over the period of 2007-2013 Estonia is set to receive more than 3.3 billion Euros of European Union funding, with 1.6 billion Euros being allocated to development of the living environment. The most important sphere of activity, and financially the largest at 0.45 billion Euros, is water management.

According to the Directive 91/271/EEC concerning Urban Waste Water Treatment, wastewater must be collected from all collection zones with a PE (population equivalent) of more than 2000. Around 933,000 people – roughly 70% of the population – live in such areas in Estonia. 89% of them are connected to the sewerage network, and the share is planned to increase to 95% by the end of 2010-2011. Wastewater collection in the remaining 5% of areas is considered to be better effected through the use of cesspits.

The remaining 30% of Estonian population is living in areas either in collection zones with a PE under 2000 or outside the collection zones and about 15-20% of population is not being supplied with central sewerage system in the next few years. Thus until 2009 the priority of the EU funding was addressed to the collection zones over 2000 PE. During the past two years the focus is also set to the collection zones from 50-2000 PE.

Smaller water management projects (under 0.96 billion euro) are mostly co-financed from the water protection programme of the Estonian Environmental Investment Centre, which is also the implementing institution for EU-funded projects. The focus of internally co-financed investments is set on developing sewerage systems on officially confirmed collection zones while the need for decentralized wastewater treatment (collection zones under 50 PE, single households, small enterprises) is not yet being perceived in local level. Also the procedures and monitoring systems are not yet developed enough to allow proper supervision and control over the decentralized wastewater treatment systems. These are the main reasons why there is no standardized or integrated approach for decentralized waste water management in Estonia.

Another issue regarding decentralized wastewater treatment is sludge treatment. The handling of sludge from small scale treatment plants is also becoming a problem due to the lack of proper centralized treatment facilities. Very often the excess sludge from even larger treatment systems (up to 1000 PE) is just collected and spreaded to fields or, even worse, the excess sludge from biological treatment section is not removed regularly causing the decrease in efficiency of aftertreatment processes (e.g. sedimentation into biological ponds).


Estonian legislation for decentralized wastewater treatment:
Main act of law regarding the water management is the Water Act, which regulates the use and protection of the water as a resource. The Water Act is specified by several sub-level acts which specify the water basins and sub-basins, requirements for wastewater treatment facilities, treatment quality and sludge treatment, procedures giving and changing of water use permits etc.

There are no separate or special requirements for the decentralized wastewater treatment facilities. The requirements for treated wastewater are appointed in the water permit by the local department of Environmental Board considering the water quality of the recipient water body and/or the groundwater protection level. The most stringent requirements for decentralized treatment systems are the same as to the normative for systems between 2000-9999 PE, which means for BOD 15 mg L-1; for COD 125 mg L-1; for Ptot 1.5 mg L-1 and for suspended solids (SS) 25 mg L-1. Nitrogen removal is not required.

Players

Association of Estonian Water Companies (member of European Union of National Associations of Water and Wastwater Services) is the voluntary union of companies that are operating in water and wastewater services, aiming to help to improve the technical and financial base of its members (In Estonian)
Estonian Water Association (member of European Water Association and Global Water Partnership) is the voluntary union of individuals and corporate bodies dealing with water management problems, aiming to develop water management in Estonia (In Estonian)
The Estonian Association of Civil Engineers (member of the Estonian Association of Engineers and of the European Council of Civil Engineers) – established in 1991; is a voluntary and non-profit association for civil engineers. Main goals are forward the development of construction, take part in formation of civil policy in technics, science and education etc.
Estonian Association of Water supply and Wastewater Engineers (member of Estonian Association of Civil Engineers) - established in 2008. Members of association are voluntarily joined specialists of water supply and wastewater (environmental engineering).Main goals are e.g. providing professional development for engineers in field, sharing experiences, taking part in the creation and dissemination sector-specific standards; and raising reputation of engineers profession.

Pratical Examples

As the procedures and monitoring system has not been developed enough to allow proper supervision and control over the de-centralized wastewater treatment systems and due to the lack of knowledge and experience with different systems, the solutions for de-centralized wastewater treatment are mainly dictated by the investment costs of the establishment of the treatment plant.

Cesspools – typical solution for the real estate development areas near the cities were the centralized sewerage system is planned to be built. In many of those areas the development has slowed down or stopped at all because of the financial crisis. Thus, it happens quite often that a highly-valued piece of real estate is sold without proper wastewater treatment system and the new owner has to deal with the problem either by emptying the cesspool frequently or not having it at all. There are also large areas of settlements which were established in the time of Soviet Union. In these areas the cesspits are often not watertight, either on purpose (holes made in the bottom) or due to the poor construction quality of those times. However, some of these areas (especially in more densely populated areas in Harju and Pärnu county) are being supplied with the central sewage system in the near future.

Septic tank. Although it is not allowed, sometimes the mechanically treated wastewater is discharged directly into watercourse. In many cases the owners of the treatment systems are even not aware of how their sewage system works.

Soil infiltration after mechanical treatment (septic tank, infiltration bed). Mechanically pre-treated wastewater can only be infiltrated into soil in case the groundwater is well protected and the highest level of groundwater is 1.2 meters below the infiltration level, which rules out some parts of Estonia (e.g. northern and western Estonia). However, the infiltration systems are quite often used all over the country because in many of the sites there is no watercourse to discharge the effluent to and thus the infiltration is the easiest and economic solution for wastewater treatment. There are several companies that are selling the set of infiltration systems and also guides for establishing these systems are available in Estonian (e.g. http://www.pci.ee/feb/Juhendid/6453-1.pdf).

Intensive biological treatment systems are not very widespread because of the relatively high investment and operational costs. However, these are getting more popular in the areas where more primitive systems (infiltration beds) are either not allowed (e.g. areas of vulnerable groundwater or watercourse) or where there is not enough space for other systems.

Biological filters (e.g. Bioclere trademark) – were widespread biological treatment systems for small communities in Estonia from 1995 till 2010 as relatively low–cost and easy-to-establish systems which according to the technology providers “need extremely little maintenance and have very low exploitation costs compared to the other biological treatment systems” and were installed as “black boxes”. Often these systems were designed incorrectly (e.g. without proper pre- and aftertreatment in form of missing septic tank and/or biological pond) and had no proper maintenance. Recently, many of those systems have been replaced because of the poor purification efficiency.

Activated sludge treatment (AST) systems – are not very common because of the high investments and relatively high operation costs. However, several companies have recently developed compact manufactured solutions for AST plants which in interaction with proper maintenance enable to have good quality of effluent.

Extensive biological systems – are not very widely used in Estonia, mainly because of the prejudices of their malfunction due to the cold climate and their need for larger area.

However, recent study that was conducted by the researchers of University of Tartu showed that hybrid constructed wetlands could be an environmentally and economically sound alternative to other biological wastewater treatment technologies, especially for small communities (under 100 PE). On the basis of that study the “Estonian guidelines for the use of hybrid filter systems and constructed wetlands for wastewater treatment” were developed (Institute of Technology University of Tartu, Institute of Ecology and Earth Sciences University of Tartu. Edited by Alar Noorvee, 2007). Available only in Estonian: http://www.geo.ut.ee/pinnasfilter/pinnasfilter_juhend.zip.

A good example of such technology is a constructed wetland system treating wastewater from basic school in Paistu. With its proper design and outstanding purification results it can be considered one of the best systems in Estonia (http://www.cbr.tulane.edu/PDFs/ooveletal2007.pdf). Thus, correctly designed and properly maintained constructed wetlands and filter systems could be a sustainable approach for de-centralized wastewater treatment in our region, especially because the space is usually not the limiting factor for treatment technology. Therefore, introduction of best practices of constructed wetland system technology (e.g. enhancing oxygen transport into the wetland matrix by re-circulation and batch-operation) together with novel filter materials (phosphorus removal with oil shale ash sediments) can lead to development of more compact systems which can meet the most stringent requirements while having fairly low operating costs.

If the space is limiting factor or effluent re-use is needed, more intensive technologies have to be applied. Currently, research about the effectiveness of purification of different wastewater treatment solutions is done both in Finland and in Estonia during the MINWA project. The aims of the MINWA project are the exchange of knowledge and experience in treating waste water in sparsely populated areas, education, training and the dissemination of good practices. Research regarding the effectiveness of different treatment systems is implemented for the duration of the 3 year project. Models for treatment systems, maintenance and service, as well as follow-up systems, are being developed in co-operation between Estonia and Finland. One of the technologies to be tested is membrane treatment which allows effluent quality equal to bathing water and saves space as the secondary settling tank can be excluded from the AST process.