DRAFT Eutrophication Good Practice Guide

Good Practi ce Guide Series February2011

Local Authoriti es Internati onal Environmental Organisati on

Miti gati ng Eutrophicati on:A Manual for Municipaliti es

iGood Practi ce Guide Series: Miti gati ng Eutrophicati on

The role of municipaliti es tackling eutrophicati on

The problems of eutrophicati on pose a serious threat to natural and human environments. Internati onal conventi ons, European directi ves and nati onal strategies have been drawn up over the past several decades to miti gate its e ects. The prospects for marine environments a ected by eutrophicati on are positi ve with increasing awareness of the need for acti on. Most strategies focus on large-scale, setti ng targets to reduce nutrient discharges by restricti ng outputs from industry, limiti ng the use of harmful agricultural products

and improving centralised wastewater treatment plants.

There is scope for municipaliti es to take acti on at the local level and contribute towards these higher-level e orts. This manual provides a background to eutrophicati on and areas that municipaliti es can infl uence. It supports a checklist that can be used as a practi cal guide for adopti ng a miti gati on project; it is available

from the KIMO secretariat at the address at the bott om of this page.

Research and acti on on the potenti al of small-scale wastewater treatment, riparian bu ers, and wetland restorati on to achieve nutrient reducti ons have produced a wealth of knowledge to help understand how

to combat eutrophicati on, this o ers valuable insight on the scope for municipaliti es to take acti on.

The research that underpins this manual involved an extensive literature review on eutrophicati on, small-scale wastewater treatments and other miti gati on measures; it identi fi ed over 60 experts and invited them to o er comments insight and guidance in their parti cular area of experti se. The informati on gathered was

compiled into a manual and checklist for use by municipaliti es.

The informati on contained in this document, to the best of our knowledge wascorrect at the ti me of publicati on. This manual is meant only as an aide memoire

and KIMO assume no responsibility for any omission or any situati on that mayarise as a result of using this guide

A Checklist has been produced to accompany this manual that is available from KIMO electronically

For more informati on contact:

Craig Baxter or John MouatKIMO Secretariat

Environmental LiaisonC/o Shetland Islands Council, Infrastructure Services, Grantf ield, Lerwick, Shetland, ZE1 0NT

[email protected]

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Good Practi ce Guide Series: Miti gati ng Eutrophicati on

Miti gati ng Eutrophicati on

A Manual for Municipaliti es

Craig BaxterMA (Hons), MSc

Published by:Kommunenes Internasjonale Miljorganisasjon (KIMO),

c/o Shetland Islands Council, Infrastructure Services, Grantf ield, Lerwick, Shetland ZE1 0NT

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Executi ve summary

Eutrophicati on is an environmental problem that a ects surface waters across the globe. Marine and aquati c environments and their ecosystems are threatened by the over-loading of nutrients from human sources. There are various streams that contribute to the problem including surface water run o , discharges into ground water and depositi on from the atmosphere.There are both point and di use inputs of nutrients, with the latt er more challenging to manage. The e ects of eutrophicati on are well understood and the internati onal community are engaged in a number of miti gati on acti viti es.Internati onal, regional and nati onal governance have brought about various legislati ve changes to limit harmful acti viti es that discharge nutrients. The threats posed by eutrophicati on and the challenges in addressing it are issues for everyone. Whilst top ti ers of government are seeking to bring about positi ve change through policy, there is scope for small-scale localised projects to contribute.Wastewater discharges are understood to make a signifi cant contributi on to the problems of eutrophicati on. There has been considerable research and innovati on into improving the e ecti veness of on-site and small-scale treatment systems, parti cularly in Nordic countries. Modern package plants, innovati ve technologies and improved conventi onal systems now o er scope to achieve considerable reducti ons for homes and sett lements not connected to centralised treatment plants.There are also a number of good methods that demonstrate the potenti al of riparian and wetland management to reduce inputs from di use sources. Municipaliti es can address eutrophicati on by carrying out such projects on land they own or are responsible for. Riparian bu ers and natural wetlands o er more benefi ts than just potenti al to absorb nutrients, they can increase biodiversity, stabilise riverbanks and enhance landscape amenity.These measures have real potenti al for improving the state of the worlds eutrophic surface waters. In order to deliver an e ecti ve project, it is important that a coherent and structured approach is adopted that involves all concerned parti es, ensures best available technology is used and that projects are fi t for purpose.

Aims Objecti ves To provide practi cal guidance for municipaliti es to reduce the impacts of eutrophicati on.

To highlight the scope for wastewater treatment and riparian zone improvements to limit the discharge of nutrients.

To equip municipaliti es with the necessary knowledge and skills to undertake a eutrophicati on miti gati on project.

To consolidate informati on about eutrophicati on into an accessible format.

To summarise examples of best practi ce projects and initi ati ves for installing and upgrading small-scale wastewater treatments and an up to date review of small-scale treatment systems.

Highlight the scope for achieving nutrient reducti ons with riparian and wetland projects to moti vate municipaliti es to take acti on.

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Contents PageEXECUTIVE SUMMARYI1.0 INTRODUCTION 12.0 EUTROPHICATION 2 2.1 What is eutrophicati on? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1.1 An Increase in primary producti on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1.2 Algal blooms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1.3 Increased turbidity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1.4 Oxygen depleti on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1.5 A complex process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 How does eutrophicati on a ect the environment?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2.1 Ecological impacts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2.2 Social impacts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2.3 Economic impacts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 Nutrient sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3.1 Agriculture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3.2 Municipal Wastewater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3.3 Industrial land-based sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3.4 Transport. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.4 Case Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4.1 Case Study: The Gulf of Mexico. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4.2 Case Study: The Gulf of Riga. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.0 POLICY CONTEXT 11 3.1 Internati onal agreements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1.1 The Nitrogen Oxide Protocol (1979). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1.2 The Gothenburg Protocol (1999). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1.3 The OSPAR Conventi on (1992). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1.4 The Helsinki Conventi on (1992). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.1.5 The IMO and MARPOL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.2 EU Directi ves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.2.1 The Nitrates Directi ve (1991). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.2.2 The Urban Waste Water Treatment Directi ve (1991). . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.2.3 The Integrated Polluti on Preventi on and Control Directi ve (1998). . . . . . . . . . . . . . . . 13 3.2.4 The Water Framework Directi ve (2000). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.2.5 The Marine Strategy Framework Directi ve (2008). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.2.6 The Common Agricultural Policy (since 1962). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.2.7 The EU Strategy for the Balti c Sea Region (2009). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.3 Nati onal e orts to tackle eutrophicati on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.3.1 Denmark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.3.2 Sweden. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.0 WHAT CAN A MUNICIPALITY DO TO TACKLE EUTROPHICATION? 165.0 WHAT A MUNICIPALITY CAN DO: SMALL-SCALE WASTEWATER TREATMENT 17 5.1 Wastewater treatment principles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 5.2 TREATMENT SYSTEMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.2.1 Infi ltrati on systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.2.2 Package Plants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.2.3 Sorti ng systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.2.4 Constructed wetlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

vGood Practi ce Guide Series: Miti gati ng Eutrophicati on

Contents Page 5.3 Research into small-scale systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.4 Good practi ce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.4.1 Engaging the user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 MINWA Demonstrati ons 25 5.4.1.1 Sand fi lter and P removal system installati on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.4.1.2 Dose-load biochemical system operati on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.4.1.3 A village wastewater plant. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.4.1.4 Maintaining on-site systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.4.2 The Karelia project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.4.3 Coaliti on Clean Balti c. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.4.3.1 Vadsbro case study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.4.3.2 Eco-Sanitati on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5.5.4 Nordic Innovati on Centre. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5.4.5 A growing body of knowledge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306.0 WHAT A MUNICIPALITY CAN DO: RIPARIAN BUFFERS AND NATURAL WETLANDS ON MUNICIPALITY OWNED LAND 31 6.1 Riparian bu ers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 6.2 Wetland restorati on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327.0 A METHOD FOR MUNICIPALITIES 33 7.1 Identi fying stakeholders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7.1.2 System users in wastewater projects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7.1.3 Expert groups. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7.2 Establish baseline conditi ons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7.2.1 Socio-economic informati on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 7.2.2 Existi ng infrastructure in wastewater projects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 7.2.3 Environmental conditi ons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 7.2.4 Predicti ons and projecti ons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 7.3 Identi fying the best approach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 7.4 Implementi ng the project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 7.4.1 Costi ng. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 7.4.2 Impact reducti ons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 7.5 Monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368.0 CONCLUSION 36REFERENCES 37APPENDIX 1- USEFUL LINKS TO FURTHER INFORMATION 42

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List of TablesTable 1: Impacts of eutrophicati on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Table 2: Wastewater treatment stages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Table 3: Acti on Plan for the Aquati c Environment Denmark. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Table 4: Wastewater treatment stages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Table 5: Innovati ve small-scale wastewater treatment systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Table 6: E ecti veness of innovati ve wastewater treatment systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Table 7: E ecti veness of di erent onsite wastewater treatment systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Table 8: Vadsbro study fi ndings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Table 9: Wetland capacity to remove nutrients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Table 10: Stages to consider in undertaking a nutrient reducti on project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

List of FiguresFigure 1: Eutrophicati on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Figure 2: The nitrogen cycle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Figure 3: The phosphorus cycle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Figure 4: Large-scale wastewater treatment processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

List of PanelsAlgal bloom in surface waters (WWF- Paivi Rosqvist). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iiiRed ti des (California Department of Public Health volunteer Kai Schuman) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vEutrophic Beach (NOAA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Satellite image of eutrophicati on (Sea WiFS Project) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Mortality in eutrophic water (Greenpeace) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Industrial polluti on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Shipping polluti on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Gulf of Mexico map (Gulf of Mexico Foundati on) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Mississippi River drainage basin (USGS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Gulf of Riga map (Wassman) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Gulf of Riga drainage basin (Wassman) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Gulf of Riga cross secti on diagram (Wassman) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Septi c system (USEPA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Mound system (Converse et al) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Sand fi lter (University of Minnesota Extension) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Att ached growth fi lter (Bord Na Mona environmental products US) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Aerobic treatment (NESC West Virginia University) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Sequencing batch reactor (USEPA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Sorti ng system (Swedenviro- Mats Johansson) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Wetland processes (Natural Resources Canada) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Subsurface fl ow wetland (Natural Systems Internati onal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Free water surface wetland (Natural Systems Internati onal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Sand fi lter installati on (Swedenviro) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Raita Environment PA 0.8 SBR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Raita system in operati on (Raita Environment) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Plant maintenance (MINWA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Pumping stati on installati on (MINWA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Septi c tank (Global Dry Toilet Associati on of Finland). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Trickling fi lter (Global Dry Toilet Associati on of Finland). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28EcoSan system (Coaliti on Clean Balti c). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Filtralite syntheti c bed and spray fi lter system (Filtralite). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Riparian diagram (Chris Hoag). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1Good Practi ce Guide Series: Miti gati ng Eutrophicati on

1.0 Introducti on

This report has been produced to assist municipaliti es intending to take acti on to miti gate the e ects of eutrophicati on at a local level. Nutrients that cause eutrophicati on come from a number of sources and there are di erent politi cal actors responsible for regulati ng them. Municipaliti es play a fundamental role in miti gati ng eutrophicati on because they understand local circumstances, have detailed knowledge and usually have good contact with local stakeholders. Targets agreed at internati onal levels are translated into nati onal and local policies, which are delivered by municipaliti es and other actors appointed to protect the built and natural environment. This report seeks to provide a guide to inform municipaliti es about eutrophicati on and methods for miti gati ng its e ects.Domesti c wastewater fl ows are oft en discharged untreated into surface waters, having serious consequences for human health and the natural environment. These fl ows are nutrient-loaded and give rise to eutrophicati on of receiving waters. Whilst there are widespread e orts to improve the e ecti veness of treatment at centralised faciliti es, rural and isolated sett lements are oft en overlooked and left to discharge directly into ground and surface waters. Municipaliti es can take acti on to reduce the impacts of these remote communiti es discharges by considering small-scale and on-site treatment opti ons. The report provides an overview of some examples of best practi ce, where di erent municipaliti es and other organisati ons have implemented projects to improve small-scale wastewater treatment. These examples provide signposts for the types of projects a municipality may consider and pave the way to understanding a methodology for implementi ng projects.Di use nutrient polluti on from agriculture makes such a signifi cant contributi on to eutrophicati on that it is essenti al it be addressed at every level. Thus there is scope for municipaliti es to take acti on. Municipality owned and managed land o ers the opportunity to develop small-scale projects using riparian zone and wetland projects to contribute to higher-level miti gati on e orts. The report provides an overview of causes and e ects of eutrophicati on; various reducti on targets and miti gati on agreements; an overview of small-scale wastewater treatment technology and some examples of innovati ve and best practi ces; it explains methods that demonstrate the potenti al of riparian and wetland projects, and sets out a methodology for delivering projects.


2.0 Eutrophicati onEutrophicati on is a primary producti on of plants and phytoplankton in surface waters as a result of increased loading of nutrients and organic matt er (NSTC, 2003). This overloading into marine (saltwater) and aquati c (freshwater) environments is dramati cally increased by human land uses. Di erent acti viti es deliver a substanti al load of nutrients from sources like agricultural ferti liser run-o , untreated wastewater discharges and industrial e uents (Boesch and Brinsfi eld, 2000). The excessive nourishment of surface waters is a global problem that has far reaching social and economic consequences (Randall, 2003; Elofsson, 2003).

2.1 What is eutrophicati on?Increased nutrient loads to surface waters raise the primary producti on of phytoplankton (the basis of the food web) that impact species and the environment. When nutrient loading occurs for sustained periods it can have serious impacts that disrupt an ecosystem balance (Cloern, 2001). Discharges of nitrogen (N) and phosphorus (P) have signifi cantly increased in the 20th century because of human acti viti es (Boesch and Brinsfi eld, 2000).Nitrates and phosphates are discharged into the environment from human and natural sources and these nutrients alter ecosystem functi ons and structures. The physical impacts of eutrophicati on are an indicator of how humans a ect marine and aquati c environments (Svendsen et al, 2005). Nutrients from surface run-o , leaching, percolati on through soils and direct discharges into surface and ground waters have an e ect, fi gure 1 summarises the process. Various marine and aquati c environments are impacted by eutrophicati on, with shallow temperate low-energy water bodies parti cularly vulnerable since these conditi ons are favourable for the eutrophicati on process.

Figure 1 Eutrophicati on (HELCOM, 2009)

2.1.1 An Increase in primary producti onAs nutrient concentrati ons increase, they are transformed into organic forms through the process of N and P fi xing in aquati c plants (fi gures 2 and 3). In organic form nutrients can be consumed by phytoplankton, which multi ply and cause numerous problems.


Figure 2 The nitrogen cycle

Figure 3 The phosphorus cycle

Some species can take advantage of the increased primary producti on and others cannot adjust to the change in natural conditi ons. Higher species that feed on abundant plankton can benefi t whilst others decline with limited alternati ve food sources. This changes species compositi ons that conti nue throughout the food web.

2.1.2 Algal bloomsIncreased primary producti on causes more intense and frequent algal blooms, including harmful species like cyanobacteria. These species have serious consequences for animals and human health because of their toxicity. Algal blooms impact on the environmental and aestheti c quality of areas damaging recreati onal functi ons, mariculture operati ons and causing mortality among a number of species.


2.1.3 Increased turbidityThe higher concentrati on of plankton in surface waters limits the depth that light can penetrate by making the water more murky. Submerged plant species struggle to absorb enough of the suns energy for photosynthesis, and this impacts on species diversity through the loss of habitats and a reducti on in the oxygen that would be produced by vegetati on under normal conditi ons.

2.1.4 Oxygen depleti onWhen plankton die o they sink into deeper oxygen-limited water where bacteria decompose dead specimens and consume the already scarce supply of oxygen, having serious e ects for species and communiti es present.Poor oxygen conditi ons cause organisms to move in search of bett er conditi ons. Higher species like fi sh die o , unable to inhabit a ected areas. Hypoxic (low oxygen content) and anoxic (no oxygen present) conditi ons are extreme modifi cati ons that occur with eutrophicati on (Boesch and Brinsfi eld, 2000), which raise the demand for oxygen for both biological (biological oxygen demand: BOD) and chemical (chemical oxygen demand: COD) processes.Other problems occur under depleted oxygen conditi ons. Bacteria seek alternati ve oxygen sources to decompose plankton when there is limited dissolved oxygen and this produces hydrogen sulphide, a chemical lethal to animals. Decompositi on also releases P and N (fi gures 2 and 3) back into the water column, which further contributes to eutrophic conditi ons.

2.1.5 A complex processEutrophicati on happens as a result of a number of chemical and biological processes that combine to create the e ects outlined above. When nutrients are loaded into marine and aquati c environments, algal blooms occur that reduce oxygen levels, damage ecosystems and impact human and natural systems. Figure 1 illustrates the basic process of eutrophicati on.

2.2 How does eutrophicati on a ect the environment?The Swedish Environmental Protecti on Agency (2009) describe the sea as a multi -functi oning dynamic set of resources with provisioning; supporti ng; regulati ng and cultural ecosystems, with life-sustaining content like food and oxygen, and aestheti c and cultural resources like scenery, recreati on and species diversity. Eutrophicati on can have a far-reaching impact on the resource abundance of freshwater and marine environments, and their value to human and natural systems.

2.2.1 Ecological impactsIncreased primary producti on leads to shift s in ecosystem structures and species compositi ons. Oxygen depleti on, toxic algal blooms and the producti on of lethal chemicals can have serious consequences for ecosystems:

A loss of higher species (e.g. fi sh and crustaceans) that depend on stable oxygen levels, established habitats and reliable food sources.

Shift s in other species, in search of higher oxygen levels, and total mortality of other species.

A shift under hypoxia from large slow growth species to small fast growth species.

There are related impacts to the human environment; algal blooms make areas undesirable, impacti ng various human uses of marine and aquati c environments.


2.2.2 Social impactsUnsightly waters and unpleasant smells hinder areas a ected by eutrophicati on (Elofsson, 2003). Toxic algae can make waters unsuitable for recreati on, impact species diversity, and a ect acti viti es like fi shing and bird watching. These factors culminate into the loss of a valuable resource that impacts communiti es and visitors in a ected areas.

2.2.3 Economic impactsThe physical and social impacts of eutrophicati on have economic consequences. The damage to recreati on impacts the revenue of a ected areas with losses of visitors and tourism. Impacts on ecosystems reduce species numbers, which reduce catches for fi shing boats impacti ng fi nfi sh and shellfi sh operati ons and thus having consequences for fi sheries and the communiti es sustained by them. Some studies have examined these e ects, Diaz and Solow (1999) investi gated the ecological and economic impacts of hypoxia in the Gulf of Mexico, their fi ndings suggest that there is a disti nct lack of understanding of what e ects occur, which is alarming. Randall (2003) conducted similar research that indicated the impacts on marine ecosystems with direct economic implicati ons:

Table 1: Impacts of eutrophicati on (Randall, 2003)

Randalls research summarised in table 1 shows that there are extensive impacts on fi sheries that have direct consequences for the producti vity of associated industries.

System Area aff ected (km2)

Benthic response Benthic recovery Fisheries response

Louisiana Shelf

Kattegat, Sweden-Denmark

Black Sea, North-west Shelf

Baltic Sea

15,000

2,000

20,000

100,000

Mortality

Mass mortality

Mass mortality

Eliminated

Annual

Slow

Annual

None

Stressed, but still highly productive. No reports of mortality, except jubilees.

Collapse of Norway Lobster, reduction of demersal fi sh. Hypoxia prevents recruitment of lobsters.

Loss of demersal fi sheries; shift to planktonic species.

Loss of demersal fi sheries, shift to planktonic species. Hypoxia is bottleneck for cod recruitment.


2.3 Nutrient sourcesSome ecosystems have a level of resilience to nutrient

enrichment to cope with seasonal variati on in natural loads. This resilience is oft en not robust enough to cope with the excessive loads from human acti viti es. The two main streams of nutrients are from atmospheric and land-based sources. Atmospheric polluti on arises from acti viti es that discharge parti culates into the air leading to the depositi on of nutrients in cloud, mists and rain (precipitati on). Land-based sources mobilise in ground and surface waters as a result of point sources like industrial waste and sewage outf alls and di use sources like run-o from agriculture. In the Balti c Sea the source of 75% of N and 95% of P come from rivers and waterborne sources (HELCOM, 2007), these are input into water bodies from both point and di use sources.

2.3.1 AgricultureNutrient enrichment in agriculture can arise from arable and livestock operati ons; both N and P can be discharged and nutrient loading can be increased through operati ons like irrigati on, drainage, converti ng wetlands and other nutrient sinks to increase agricultural producti on (Boesch and Brinsfi eld, 2000). Chemical ferti lisers and pesti cides used in crop producti on can leach into watercourses through soils, and directly from surface run-o , especially during wet conditi ons. Harvests can also increase nutrient loading when crop cover is reduced and ploughing disturbs soils, releasing large amounts of nitrates. The use of manure also contributes to nutrient loading. Farms with livestock store animal waste (manure/ slurry)

and spread it onto fi elds as a ferti liser. Nutrients can make their way into watercourses from inappropriate spreading methods that fail to ensure crops absorb nutrients. Inappropriate applicati on can result in leaching (fi ltering of liquids through soil layers) and run-o into ground and surface waters. Silage is used as a feedstock for animals and is produced by storing crops (like barley straw) oft en in large silos or in pits. Structures for processing silage are oft en ine ecti ve at containing nitrate-loaded liquids produced as a by-product in fermentati on processes and these oft en end up in ground and surface waters.

2.3.2 Municipal WastewaterDomesti c wastewater discharges are a signifi cant source of polluti on that contribute to eutrophicati on. Nutrients pollutants and bacteria discharged from domesti c sources impact on water quality and human health, as well as causing and contributi ng to eutrophic conditi ons (Matuska et al, 2010). In the Balti c Sea region 30% of the N and 90% of the P from all point sources come from municipal wastewater discharges (HELCOM, 2010).


Primary

Screening Sedimentation Secondary Tertiary

Method Coarse to fi ne screens, fi lters, settling tanks, skimmers

Settling tanks, separation machinery, fi lters and skimmers

Surface aerated basins; Filter beds; biological aeration; membrane bioreactors, secondary sedimentation

Lagooning; constructed wetlands, N and P removal; disinfection e.g. chlorination

Purpose Removal of separable materials (fats, oils and greases, solids etc) that could block or damage a system

Sludge settling, removal of remaining solids, fats, oils and greases and, separation of sludge from liquid content

Degradation of the biologi-cal content of sewage by the attached and suspended growth of bacteria

Final stage of treatment to raise water quality to acceptable standard for discharge, by removing nutrients and remaining pollutants and harmful content

Process Settling, skimming, scraping and fi ltering

Settling, skimming and scraping and fi ltering

Aeration (stimulating biological breakdown of or-ganic matter by providing an oxygen source for bacteria)Filtration (providing a media for bacteria to grow on that wastewater can be passed through)Settling to remove suspended solids

Chemical precipitation (trickling wastewater through chemicals to bind contaminants e.g. P)Chemical dosing (adding chemicals to wastewater to bind nutrients for later removal as solids)Natural processes to remove contaminants like denitrifi cation by plants and animalsDosing wastewater with chemicals to kill harmful organisms

Table 2 Wastewater treatment stages (aft er Ghali, 2009)

There are varying extents to how wastewater is managed in di erent countries, regions and municipaliti es. Some have established infrastructure and regulatory systems requiring robust treatment whilst others have less formal arrangements.

Various regulati ons have imposed requirements for e ecti ve treatment in a number of countries, with extensive rules in place in the EU, parti cularly for large-scale wastewater treatment plants.

Domesti c wastewater is divided into two groups, black water: that containing human waste, and grey water: that from other domesti c streams like laundry, dish washing, showers and sinks etc.

The varying methods of regulati on of wastewater in di erent countries mean there are di erences in the extent of wastewater treatment. In some countries/ regions wastewater undergoes no treatment and issimply discharged into ground and surface waters. In order to reduce nutrient loads from wastewaters, terti ary treatment is usually required (table 2). Wastewater treatment oft en excludes terti ary treatments at both large and small-scales.


Although domesti c wastewater is a point source of polluti on it can also be considered as di use since rural dwellings and sett lements with ine ecti ve or absent of wastewater treatment are not easy to identi fy and are oft en widely dispersed over large areas. In areas with limited infrastructure and resources these discharges can contribute signifi cantly to eutrophicati on and can be di cult to manage, in the Mamonovka River Basin shared by Poland and the Russian Kaliningrad Oblast 40% of the 9,500 populati on are not connected to the sewage system (Rauti o et al, 2006).

2.3.3 Industrial land-based sources

Industrial processes contribute signifi cant loads of nutrients. Wastewater e uents and run-o from sites with poor drainage infrastructure can increase the discharge of nutrients to ground and surface waters. The consequences of these discharges to the environment can be far-reaching, high in concentrati on of N P and other hazardous substances they can damage freshwater and marine environments and contribute signifi cantly to

eutrophicati on.

Atmospheric pollutants from industry also contribute to eutrophica-ti on emitt ed during combusti on processes when nitrates are emitt ed into the atmosphere, and are deposited in acidic precipitati on (Boesch and Brinsfi eld, 2000).

Regulati on of industrial polluti on has been carried out in various countries for a number of years, and in-dustries have to adhere to certain emission level limits. Some of the European and internati onal regulatory frameworks for ensuring this are outlined in secti on 3.

2.3.4 Transport

Transport emissions contribute to the depositi on of nutrients in the marine environment. Vehicle emissions have long been understood to signifi cantly pollute the environment and, through stricter control and regulati on of vehicle emissions, there have been signifi cant changes through improved engine e ciency, cleaner fuels and the introducti on of catalyti c converters to remove pollutants.

Whilst there have been improvements to reduce road vehicle pollu-ti on, other modes of transport have been less well regulated. Shipping is predicted to contribute more polluti on than all land-based sources by 2020 (EC, 2005). Low-grade fuel use, limited polluti on preventi on practi ce and technology, and the large number of shipping operati ons make its polluti on a signifi cant contributor to already high emissions. Given the importance of shipping for transporti ng goods and for world trade, the impacts of its polluti on could signifi cantly increase in its contributi on to eutrophicati on.

Shipping wastewater also contributes to eutrophicati on, with both black and grey waters discharged. Indi-vidual vessel capaciti es to e ecti vely treat sewage vary greatly. The need for e cient reducti ons of N and P content in ship wastewater has been recognised and standards set. From 2010, the Internati onal Mariti me Organisati on (IMO: secti on 3.1.5) require considerable improvements for treati ng wastewater on ships, these have been reinforced by HELCOMs proposals to ensure reducti ons of N to less than 10mg/L and P to less that 0.5mg/L in shipping wastewater (Voigt, 2009).


2.4 Case StudiesThe causes and e ects of eutrophicati on outlined above a ect many areas, from conti nental shelf waters to confi ned seas, estuaries and other water bodies (Boesch and Brinsfi eld, 2000). Impacts of polluti on reach further than countries of origin, and impact more than just aestheti c quality.

2.4.1 Case Study: The Gulf of Mexico

The Gulf of Mexico is the ninth largest body of water in the world, land-bound by the United States and Mexico

and semi-enclosed by the island of Cuba. Around 50% of the basin is shallow water on the conti nental shelf. It is one of the warmest coastal waters in the world and over 60% of the United States land surface drains into it (USEPA, 2010) providing ideal conditi ons for eutrophicati on to occur.

The enormous body of water provides abundant resources for the tens of millions of people that live on and around its coasts. Fisheries, a variety submerged and coastal habitats, and numerous scenic areas provide a buoyant economy that is threatened by eutrophicati on.

The Mississippi River basin discharges 90% of the freshwater in the Gulf, with over 3.3 million gallons fl owing from its mouth every second (USEPA, 2010). With such an infl uence, it is no surprise that the

majority of nutrients discharged are from its catchment. It has been calculated that around 7 mil-lion tonnes of nitrates from commercial ferti lisers are discharged into the gulf each year (USGS, 2000). Esti mates suggest that the source of 50% of nitrates are from ferti lisers; 11% originate from municipal and industrial point sources; 15% from manure and, 24% come from di use sources like

atmospheric depositi on and urban run-o (USGS, 2000). The result of this nutrient loading is an extensive eutrophic zone of hypoxia in spring and summer months with signifi cant impacts on environmental, ecological and cultural assets. Nitrate loading has been esti mated to have more than doubled in the gulf since it was fi rst studied in 1985 (USGS, 2000). Federal agencies have compiled data on the causes and e ects and recognise that a holisti c approach is essenti al to achieve reducti ons (NSTC, 2003). Federal legislati on sets out nati onal objecti ves; state laws and programs interpret these higher-level laws at the regional level, and programs and initi ati ves are

carried out at the local level. All three ti ers of legislati on and acti on att empt an integrated approach to re-verse the current eutrophic state of the gulf.

10


2.4.2 Case Study: The Gulf of Riga

The Gulf of Riga is an example from a European perspecti ve. It is a major semi-enclosed basin connected by two sounds to the main Balti c Sea (the Balti c Proper). It has an area of 16,300 km2 and a volume of 424km3 (HELCOM, 2009) with two major rivers draining into it. Early infl uence on nutrient loads were from the Soviet use of chemical ferti lisers and intense livestock farming to meet export demands to the Soviet Union. Agricultural, industrial and sewage discharges created a heavily polluted marine environment.

Changes have been recorded since the 1960s with increases in both algal blooms and bott om living organisms. The faecal content of the gulf became so high under Soviet leadership that swimming was banned in the interests of human health (WWF, 2005). The 1990s saw the end of the intensive use of chemical ferti lisers and dense livestock farming (WWF, 2005; Elofsson, 2003).

The Gulf of Riga Project was set up in the early 1990s through a collaborati on of Nordic and Balti c scienti sts to establish a knowledge base on eutrophicati on and toxic substances in the gulf.

Research has been ongoing and it is now understood that there is a natural resilience to nutrient loading, with pelagic food webs having high bu ering ability to recycle nutrients, limiti ng algal blooms (Wassman, 2004). However in coastal areas N levels are twice as high as in open waters (HELCOM, 2009) and there is sti ll a need to conti nue to address nutrient polluti on. The frequency and extent of algal blooms (cyanobacteria) is lower than that in the 1980s and 1990s due to shift s in politi cal administrati on (HELCOM, 2009) but they sti ll happen.

Nutrient loads and eutrophicati on status are moderate by comparison to some other areas in the Balti c Sea Region, because of the high bu ering capacity and land use changes in recent decades. The problem of eutrophicati on sti ll remains with 40% of the catchment used for agriculture, and the main rivers discharging these and other sources of nutrients to the Gulf of Riga conti nuing the eutrophicati on.

As well as the growing body of knowledge on eutrophicati on in the gulf, miti gati on e orts are underway. The ERDF-supported Project on Urban Reducti on of Eutrophicati on (PURE) is targeti ng the reducti on of nutrients from wastewater discharges using the Gulf of Riga as a pilot study, alongside a host of other initi ati ves.

11


3.0 Policy contextThere is a legacy of policies being drawn up to protect marine and aquati c environments. Policies like the London Conventi on of 1972 focused on preventi ng dumping in marine environments, early examples like these have shaped and infl uenced modern policy-making toward more comprehensive protecti on that extends to cover impacts like eutrophicati on.

3.1 Internati onal agreements

A number of conventi ons and agreements have been established at an internati onal level to preserve and improve marine and aquati c environments.

3.1.1 The Nitrogen Oxide Protocol (1979)

The Conventi on on Long-Range Transboundary Air Polluti on aims to control and reduce the emission of nitrogen oxide from airborne sources by setti ng emissions thresholds. It came into force in 1983 and is controlled and enforced by the UNECE. Several more recent protocols have emerged as a result.

3.1.2 The Gothenburg Protocol (1999)

The UNECE Multi -e ect Protocol is designed to set ceilings on harmful emissions of sulphur dioxide, nitrogen oxides, volati le organic compounds and ammonia. One of the key moti vati ons of this agreement is to reduce eutrophicati on and its impacts. By setti ng emissions ceilings and specifi c limits for certain pollutants, the aim of the conventi on is to reduce the area of excessive eutrophicati on by 57 million hectares by 2010, an ECE working group is revising the current agreement. At the European level, this agreement is delivered through the Nati onal Emissions Ceiling (NEC) directi ve.

3.1.3 The OSPAR Conventi on (1992)

The Oslo and Paris Conventi ons were combined into the internati onal agreement for the protecti on of the marine environment in the North-East Atlanti c to prevent marine dumping and polluti on. The OSPAR Commission is responsible for monitoring environmental conditi ons in the region, ensuring the integrity of the marine environment and regulati ng European standards for hazardous and radioacti ve substances, biodiversity and eutrophicati on. It has been responsible for various reports, research and monitoring pro-grammes in the North-East Atlanti c. OSPAR have a Eutrophicati on Strategy to reduce N and P levels by 50% from the 1985 levels by 2010. Recent progress evaluati ons indicate that these targets will only be parti ally met with P reducti ons largely achieved but N reducti ons sti ll a key challenge (OSPAR, 2010).

3.1.4 The Helsinki Conventi on (1992)

The Conventi on on the Protecti on of the Marine Environment of the Balti c Sea Area is a comprehensive agreement. The governing body that enacts the conventi on is the Helsinki Commission (HELCOM). All countries bordering the Balti c Sea agree to work together to protect coastal, o shore and inland waters of the Balti c and manage polluti on from land-based sources. HELCOM develop policies, liaise with parti es and conduct research and monitoring of the marine environment. One of their key aims is to reduce the e ects of eutrophicati on.

The Balti c Sea Acti on Plan was set up to improve the environment of the Balti c Sea in four key areas: eutrophicati on, hazardous substances; biodiversity and environmentally friendly acti viti es

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(SPEU, 2009). Eutrophicati on was addressed by aiming to achieve N and P reducti ons. The plan requires signatories to develop nati onal programmes to achieve set reducti ons.

The HELCOM ministerial meeti ng in 2010 reported that recent assessments indicate that eutrophicati on sti ll remains a major threat to Balti c Sea ecosystems (HELCOM, 2010).

HELCOM outline that there is sti ll vast potenti al to achieve signifi cant reducti ons through sharing knowledge and informati on about best available techniques (BAT) and supporti ng projects like PURE. They also identi fy municipal WWTPs, single dwellings, small sett lements and small business wastewater discharges as potenti al areas for improved reducti ons (HELCOM, 2010).

3.1.5 The IMO and MARPOL

The UN set up the Internati onal Mariti me Organisati on (IMO) to develop a regulatory framework for the shipping industry for safety, security and environmental protecti on.

The Internati onal Conventi on for the Preventi on of Polluti on from Ships (MARPOL) was established by the IMO to reduce and prevent polluti on from shipping operati ons.

Six annexes outline polluti on sources from shipping and measures to reduce them. Annex four addresses sewage and requires any vessel over 400 gross tonnes or carrying more than 15 people travelling on internati onal voyages to have adequate faciliti es for treati ng and discharging sewage. Annex 6 addresses air polluti on and sets out similar controls with a technical code on nitrogen oxide emissions.

3.2 EU Directi ves

Internati onal cooperati on to tackle the problems caused by polluti on is extensive and involves a number of parti es. The examples given are a snapshot into some of the acti on taken at the intergovernmental level to tackle eutrophicati on problems, through cooperati on and setti ng internati onal standards.

At the European level there are a number of policies and directi ves that target eutrophicati on. The main policies are described but the list is not exhausti ve (for a full list and explanati on of the various relevant European directi ves the reader is directed to the European Commission website: www.ec.europa.eu/mariti mea airs/).

3.2.1 The Nitrates Directi ve (1991)

Aiming to ensure good water quality, the EU developed a directi ve for reducing the input of nitrates into the aquati c environment from agriculture. The directi ve requires member states to develop acti on programmes to minimise the use of nitrate ferti lisers and move towards using less damaging practi ces. The directi ve came into e ect in 2003 and over 300 acti on programmes have been developed in member states.

3.2.2 The Urban Waste Water Treatment Directi ve (1991)

The directi ve seeks to manage the fl ow of urban wastewater from domesti c and industrial sources. It requires member states to have adequate wastewater treatment faciliti es for the di erent sensiti viti es of receiving waters and an up to date and detailed list of catchment areas to ensure e ecti ve management. Member states are responsible for monitoring the discharges and quality of receiving waters.

It is one of the most comprehensive directi ves in terms of protecti ng surface waters from urban and municipal wastewater polluti on (Conley et al, 2002).

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3.2.3 The Integrated Polluti on Preventi on and Control Directi ve (1998)

The IPPC was introduced to reduce the impact of polluti ng industrial and agricultural acti viti es through a permit issuing scheme. Livestock farming, metal processing industries and minerals producti on are some examples covered by the directi ve.

In order to receive a permit for a parti cular operati on, strict requirements have to be met. Permits are issued to allow parti cular operati ons to occur and place the responsibility for monitoring and controlling pre-defi ned emissions levels on the permit holder, with regulati on carried out at the nati onal level by appointed agencies.

3.2.4 The Water Framework Directi ve (2000)

The directi ve requires member states to develop management plans for river basins in their region including those that cross borders, to develop baseline informati on and measures required to achieve good environmental status, working with neighbouring countries where necessary. Member states were required to develop baseline scenarios by 2004, produce management plans by 2009 for the period 2009-2015 and be ready to implement these plans by 2012.

The WFD takes an ecosystems approach, involving all stakeholders and considering the multi ple-uses of water resources to produce more e ecti ve management plans.

3.2.5 The Marine Strategy Framework Directi ve (2008)

The ecological dimension of the EU mariti me policy (SPEU, 2009), the MSFD directi ve sets out a framework for the EU and neighbouring non-member states to develop plans to achieve good environmental status of EU marine waters by 2020. Devising a strategy that establishes marine regions based on geographical and environmental conditi ons, the directi ve requires member states to defi ne what good environmental status is in their region, and to work with other countries to develop a set of environmental targets and monitoring projects to achieve it.

3.2.6 The Common Agricultural Policy (since 1962)

CAP is an EU subsidy system that supports agriculture and funds its programmes. Initi ally it promoted the expansion of agriculture across Europe, which led to widespread large-scale farming operati ons and intensive use of chemical ferti lisers and pesti cides that caused habitat losses, reduced vegetati on cover and increased nutrient loading. However recent reforms have revised these agendas and focused on issues of sustainability and protecti on of the environment. CAP helps to miti gate eutrophicati on through these broader goals. With incenti ves like o ering green payments for farms that reduce ferti liser use and adopt organic producti on methods. CAP is helping to address the issue of eutrophicati on by reducing the intensity of agriculture on receivng environments.

3.2.7 The EU Strategy for the Balti c Sea Region (2009)

As more countries have joined the EU in recent years there has been raised awareness amongst policy makers to develop a plan for the area as the EU extends east. The strategy for the Balti c Sea Region has four key principles aimed at promoti ng and improving the quality of the region socially, culturally, economically and environmentally. Since adopti on in 2009 the environmental objecti ves have been developed into a network of marine protected areas, targets for reducing phosphate inputs from detergents in municipal wastewater, the provision of funding for programmes and research and, improving cross-border cooperati on. A key aspect of the strategy is to use existi ng and emerging nati onal, regional and pan-Balti c strategies from statutory and non-governmental bodies and to enhance them with support and funding.

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3.3 Nati onal e orts to tackle eutrophicati onHELCOM and OSPAR progress assessments indicate that reducti on targets will only be parti ally met. In-ternati onal conventi ons and European policies are central to achieving su cient reducti ons by promoti ng collaborati ve e orts to deal with transboundary problems. These top-ti er agreements are largely delivered through policies and programmes at the individual country level. Whilst some nati ons struggle to achieve reducti ons, others are leading the way, developing strategies to tackle eutrophicati on.

3.3.1 Denmark

Danish environmental policy lends itself well to illustrate e ecti ve miti gati on. Nutrient reducti ons were identi fi ed as a central issue in protecti ng the Danish environment, and their policies refl ect this (rtebjerg et al, 2003).

Responsibiliti es for environmental protecti on rest largely with individual municipaliti es and counti es, a common feature of governance in Nordic countries (Katko, 2004). The responsibiliti es are overseen by the Ministry of Environment and the Environmental Protecti on Agency (EEA, 2005). The Acti on Plan against Polluti on with nutrients of the Danish Aquati c Environment (the APAE), is the nati onal plan that tackles eutrophicati on, table 3 summarises the progression of the plan over ti me.

APAE I APAE II APAE III

50% N reduction target

80% P reduction target

Agriculture, municipal and industrial discharges main sources

Expand sewage plants and reduce agricultural inputs

P reductions achieved,

N discharges still a problem

Agriculture key to addressing problem

Establish wetlands on agricultural land. Control manure

storage and spreading

P and N targets met

Additional 13% N and 50% surplus P reduction targets

Crop buff er zones, set aside land, taxation of P use in fodder, and support

for research into fodder effi ciency

1987 1998 2005Table 3 Acti on Plan for the Aquati c Environment Denmark

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The three key sources of polluti on identi fi ed by APAE have been miti gated to varying extents:

Industrial point sources: regulated through the Environmental Protecti on Act, which translates the requirements of the IPPC directi ve, with 80% of industries connected to municipal treatment plants (EEA, 2005).

Municipal sources: largely miti gated through wastewater treatment improvements by the translati on of the Urban Wastewater Treatment Directi ve in the APAE and through county regional plans and municipal wastewater plans. 90% of households are connected to municipal wastewater treatment plants, 86% of which carryout advanced treatments (EEA, 2005).

Agriculture: sti ll a problem area, the current APAE concentrates on nutrient discharges from agriculture, improving research into bett er techniques and technologies and developing bett er crop and livestock practi ces.

Denmark has made considerable progress in areducing nutrients to surface waters. Successes are largely due to e ecti ve policy-making and promoti on of self-governance and this is underpinned by a thorough understanding of the problem. A Nati on-wide Monitoring Programme set up in the 1990s provided data on nutrient levels from which reducti on targets were set (rtebjerg et al, 2003). Conti nuous monitoring has provided a good baseline for developing e ecti ve targets and programmes (Svendsen et al, 2005) and is also a good indicator of the e ecti veness of measures taken.

The APAE in Denmark has been periodically revised and updated to deliver the most e ecti ve reducti ons and is complemented by a host of other policies and legislati on at nati onal, regional and local levels. Since developing and implementi ng the plan Denmark has exceeded the targets set by the Urban Wastewater Treatment Directi ve.

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3.3.2 Sweden

Swedish environmental policy has a history of innovati on; driven by a collecti ve approach that acti vely engages stakeholders for e ecti ve protecti on and miti gati on (Bouveng, 1978).

This spirit of comprehensiveness has steered nati onal policy towards addressing environmental issues through one main initi ati ve. The Environmental Policy Objecti ves lists sixteen key areas to protect and enhance the environment.

The hierarchy of Swedish environmental policy is similar to that of Denmark. The parliament adopts the environmental objecti ves; the government oversee the implementati on; the Environmental Objecti ves Council (via the Swedish EPA) coordinate agencies to achieve objecti ves, and County Boards and Municipaliti es deliver them on the ground. One of the sixteen objecti ves is Zero Eutrophicati on by 2020 to achieve good environmental status in line with the Water Framework Directi ve. A set of interim targets has been drawn up to ensure success by 2020 (Swedish EPA, 2009b), which have indicated that the target of zero eutrophicati on will be unlikely to have been achieved by 2020 because of the slow pace of ecosystems to recover and the e ects of transboundary polluti on. Additi onal measures have been implemented, including an outright ban on the use of phosphates in detergents to reduce discharges from domesti c wastewater fl ows (Swedish MoE, 2009).

Miti gati on measures are set out under three broad headings: E cient Energy and Land Use, Non-toxic, Resource-saving Environmental Life Cycles and, Management of Land, Water and the Built Environment (Swedish EPA, 2009c).

Through these strategies various agencies are involved in addressing eutrophicati on. Similar to other Nordic countries Sweden tends towards self-governance with water managed by municipaliti es (Katko, 2004). A number of initi ati ves have been established to address the problems of inadequate wastewater treatment with collaborati ve e orts between various agencies.

4.0 What can a municipality do to tackle eutrophicati on?Nutrients sources are di cult to identi fy downstream and this is an important factor in considering what can be done to address the problem (Boesch and Brinsfi eld, 2000). Previous secti ons have detailed how policy and internati onal strategies have been drawn up to reduce inputs from di erent sources. Policies that strike at the heart of the problem have a signifi cant impact in tackling eutrophicati on.

Large-scale wastewater treatment plant improvements, changes in agricultural policy to infl uence practi ce, and regulati on of harmful pollutants are among the acti ons taken by upper ti ers of governments to reduce the fl ow of nutrients into marine and aquati c environments.

There is scope for municipaliti es to take acti on to further reduce nutrient fl ows at the local level. The funding and support provided for nati onal and internati onal strategies is considerable, municipaliti es can apply modest lower cost and small-scale measures within their regions to deliver improvements and considerable reducti ons.

A number of initi ati ves are underway that seek to share knowledge and experience, pull together resources and highlight to communiti es the needs and benefi ts of combati ng eutrophicati on and reducing nutrients.

17


5.0 What a municipality can do: small-scale wastewater treatmentDomesti c wastewater fl ows in rural areas are oft en neglected when centralised treatment systems are upgraded (Massoud, et al, 2009). This means a considerable proporti on of rural homes are contributi ng to the problem of eutrophicati on by discharging nutrient-loaded wastewater into ground and surface waters (Swedish EPA, 2002). The explanati ons for inadequate treatment systems vary, but some common reasons include the change in use of holiday homes to permanent residences that only have basic septi c systems designed for occasional use. In other regions limited resources and regulati on mean there is simply no requirement for homes to have wastewater treatment. The latt er of these two problems makes the challenge for municipaliti es considering improvement projects di cult, as some systems may not be suitable if they require to be retrofi tt ed into an existi ng home, however as some of the following examples show, it is possible.

There is a growing body of experti se on small-scale treatments, with Nordic countries developing systems, initi ati ves and research projects aimed at sharing and exchanging knowledge and understanding of best available technology for small-scale systems.

Best practi ce examples of wastewater treatment are informed by research with an understanding that sharing experience is as vital as knowing what systems will suit a site. A common theme in best practi ce is good working partnerships, with contributi ons from manufacturing and supply sectors; academic insti tuti ons; environmental agencies; non-governmental organisati ons and municipaliti es. It is this ethos that enables successful projects, sharing a wealth of experience and knowledge.

5.1 Wastewater treatment principlesBefore describing projects that demonstrate best practi ce, it is important to understand the principles that underpin wastewater treatment systems. Any system deals with collecti ng, treati ng and disposing waste (Massoud et al, 2009). Treatment is the essenti al stage for achieving nutrient reducti ons and three stages can be identi fi ed. Figure 4 illustrates these stages in large-scale centralised treatment systems. These basic steps can be adapted in small-scale systems to achieve di erent nutrient reducti ons:

Figure 4 Large-scale wastewater treatment processes (Svenskt Vatt an, 2002).

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PrimaryScreening Sedimentation Secondary Tertiary

Method Coarse to fi ne screens, fi lters, settling tanks, skimmers

Settling tanks, separation machin-ery, fi lters and skim-mers

Surface aerated basins; Filter beds; biological aeration; membrane bioreactors, secondary sedimentation

Lagooning; constructed wetlands, N and P removal; disinfection e.g. chlorination

Purpose Removal of separable materials (fats, oils and greases, solids etc) that could block or damage a system

Sludge settling, removal of remaining solids, fats, oils and greases and, separation of sludge from liquid content

Degradation of the biological content of sewage by the attached and suspended growth of bacteria

Final stage of treatment to raise water quality to acceptable standard for discharge, by removing nutrients and remaining pollutants and harmful content

Process Settling, skimming, scraping and fi ltering

Settling, skimming and scraping and fi ltering

Aeration (stimulating biological breakdown of organic matter by providing an oxygen source for bacteria) Filtration (providing a media for bacteria to grow on that wastewater can be passed through) Settling to remove suspended solids

Chemical precipitation (trickling wastewater through chemicals to bind contaminants e.g. P) Chemical dosing (adding chemicals to wastewater to bind nutrients for later removal as solids)Natural processes to remove contaminants like denitrifi cation by plants and animals Dosing wastewater with chemicals to kill harmful organisms

Table 4 Wastewater treatment stages (Aft er Ghali, 2009)

5.2 Treatment systemsSmall-scale and onsite treatment processes vary, some fully treat wastewater to a high standard before discharging into the natural environment, whilst others carry out some basic primary or secondary processes and depend on receiving environments to further treat e uents.

19


5.2.1 Infi ltrati on systems

Septi c SystemsThe most frequently used onsite technology; septi c systems separate solids out through fi lters and a sett ling tank. Liquid e uent is dosed into a drain fi eld through pipes that allow it to soak away through soils and eventually into ground water. Some secondary treatment can occur in the sludge in the septi c tank, but nutrient-loaded e uents rely on the capacity of soils and geology for treatment before reaching ground water.

Mound SystemsAn advanced septi c system that compensates poor soil capacity by constructi ng an infi ltrati on mound, using di erent layers of fi lter material to att empt to treat e uent more e ecti vely.

Sand FiltersFollowing similar principles to septi c systems, sand provides a fi ltrati on surface before discharging. Wastewater is passed through a sand medium where bacteria can grow to consume organic matt er. Some advanced systems use additi onal layers of chemicals to remove P and others recirculate e uent through the system several ti mes before discharging.

5.2.2 Package PlantsPackage plants replicate some of the industrial-scale processes described in fi gure 4 at smaller scales. They oft en feature unique patented components designed by manufacturers to serve a specifi c purpose, these vary between systems, but all are designed to achieve higher quality e uents. There are some common processes and components used in package plants that are summarised below.

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Aerobic treatmentWastewater is dosed into an aerati on chamber

where pumps force through air to provide oxygen for bacterial decompositi on of organic matt er and to mix wastewater. Sett ling removes biomass formed by bacteria in aerated wastewater.

Anaerobic treatmentWastewater is dosed into a tank where it is retained to allow biological processes to occur. The tank is made up of solid fi lter material that wastewater is dosed into under anaerobic conditi ons, with extensive bacterial growth on the water surface. Dosing systems circulate wastewater in di erent ways to achieve biological treatment. Anaerobic conditi ons favour N consuming bacteria, thus anaerobic treatment is useful for reducing N.

Att ached growth fi lters Filter material provides a surface for bacteria to grow on that consume organic matt er in wastewater. Submerged fi lters use aerati on to provide aerobic conditi ons for bacteria; other fi lters use moti on toensure oxygen for bacterial decompositi on, for example, rotati ng fi lters.

Chemical TreatmentVarious chemicals can be used to raise e uent quality either as an additi onal polishing stage, or as a pre-treatment. Chlorine and other disinfectant chemicals are added to kill harmful bacteria that remain in e uents as a fi nal process. Chemical like iron ochre can be added to bind P for later removal through sett ling. It can also be added as a layer in some fi lter systems.

21


Sequencing Batch ReactorsA process of combined biological treatment and sett ling in sequence to achieve a higher e uent quality. In a cycle the processes of aerati on, mixing, biological digesti on and decanti ng of treated e uent are carried out. A number of di erent processes can be incorporated into a package plant to achieve a higher quality of e uent. By combining some of the processes above, secondary and even terti ary stages of treatment can be achieved at small scales. Complex soluti ons have been developed to meet the demands of the growing on-site treatment market as a result of increasingly e ecti ve regulati on.

5.2.3 Sorti ng systemsSorti ng systems use an innovati ve approach to manage wastewater by separati ng black and grey water for individual treatment. Black water can be separated from grey water, which can be recycled for irrigati on or treated accordingly. Harmful black water can be further sorted into solid and liquid wastes, where solids can be diverted to composti ng tanks and N-loaded liquids can be stored and used as a ferti liser for crops.

22


5.2.4 Constructed wetlands

Wetlands have a capacity to absorb pollutants from water and raise its quality. Natural processes can reduce contaminants and benefi t water quality, habitats and biodiversity. Constructed wetlands replicate these natural processes to treat wastewaters. Under controlled conditi ons, these systems o er potenti al for secondary and terti ary treatments. Some systems are used for total treatment and others as a fi nal polishing stage. Two main systems are used.

Subsurface fl ow wetlandsThe subsurface method uses a gravel medium and vegetati on (usually reeds) to treat wastewater. The water level is kept below the surface of the gravel to ensure minimal exposure to humans and to limit the risk of increasing insect populati ons (USEPA, 2000). Aerobic conditi ons around roots and water surfaces allow some removal of N, but anoxic conditi ons are limiti ng. Terti ary treatment can be achieved with longer retenti on of wastewater, aerati on devices and verti cal-fl ow systems, which raise oxygen levels for e ecti ve treatment. P, metals and persistent organic pollutants are bound in sediments, and accumulate over ti me; their levels are reduced from e uent discharges but remain in the wetland system.

23


Free water surface wetlandsThe second type of wetland has an open water surface with a bed of clay soil for vegetati on to take root, this vegetati on shelters the water surface from the sun, limiti ng algal growth and reducing water turbulence from wind. Wastewater is spread over a large area at a shallow depth, to achieve e ecti ve removal of nutrients by oxidising N and P, adsorpti on in soils and removal by microbial processes and plant consumpti on.

5.3 Research into small-scale systemsOnsite and small-scale systems range from fully fabricated total treatment systems to basic structures that rely on natural processes. Research plays an important role in developing an understanding of these systems and which are best placed to deliver nutrient reducti ons. A number of studies have been carried out to evaluate di erent small-scale systems. The Swedish Delegati on for Sustainable Technology carried out a project in partnership with Stockholm Water that ran over a number of years to examine the e ecti veness of di erent onsite systems. The study looked at three types of system and compared the concentrati ons of nutrients and organic matt er in outf lows (Qvarnstrom and Bergstrom, 2002). The study aimed to evaluate the systems to fi nd the most hygienic, easy to use and economical processes that did not consume excessive resources (Hellstrom and Jonsson, 2006).

Plant Descripti onBiovac 5pe

Upoclean 5pe

Package plant with SBR, acti vated sludge and chemical precipitati on.

Biotrap Package plant with submerged fi lter complimented by chemical precipitati on.

ALFA/ BAGA RVBK5ALFA MRCP Package plant with submerged fi lter complimented with chemical precipitati on.

Toilet EcoVac or Clever with Wost Man Ecology fi lter

Storage tank for black water and treatment of grey water in small sand fi lter.

Toilet Dubblett en BB Innovati on and large sand fi lter

Urine separati ng toilet and storage tank for urine. Septi c tank and large sand fi lter for remaining sewage.

EkoTreatKemira Large sand fi lter complimented with in-house chemical precipitati on.

Table 5: Innovati ve small-scale wastewater treatment systems (aft er Hellstrom and Jonsson, 2006)

24


The study was reported in academic papers as well as an informati on brochure. The systems examined are summarised in table 5 and the fi ndings in table 6, which show the percentage of reducti ons achieved relati ng to each polluti ng substance.

Table 6: E ecti veness of innovati ve wastewater treatment systems (Hellstrom and Jonsson, 2006)

The study concluded that all systems could remove signifi cant levels of P; the most e ecti ve being a sorti ng system with sand fi lter and in-house chemical precipitati on and it concluded that sand fi lters were e ecti ve for removing organic matt er (Hellstrom and Jonsson, 2006). It highlighted that package plants require professional maintenance and technical support for e ecti ve long-term P removal and that N removal was most e ecti ve in sorti ng systems. Some package plants use passive processes that are less energy-intensive and may therefore be bett er suited for use in areas where low running costs are essenti al. A number of plants assessed in the study use chemical precipitati on to achieve e ecti ve nutrient reducti ons so cost, availability and practi cality of replenishing chemicals may be an important considerati on for a project.The study is a helpful tool for deciding what system can be used for a site to achieve parti cular nutrient reducti ons. Sorti ng systems oft en require in-house components and complex set-ups and therefore may not be suited for retrofi tti ng, there is research in this area beyond the scope of the manual, readers are directed to Menzinger et al, 2010.Other initi ati ves have been set up to increase the knowledge of on-site and small-scale treatments. The MINWA project is comprised of various organisati ons in Finland from both the private and public sectors that aim to promote knowledge of on-site systems. Their work has examined existi ng systems and their e ecti veness and involves gathering regular data on system discharges for COD, BOD, N, P and suspended solids. This informati on is publicly available and intended to provide imparti al informati on to those considering installing a system.One outcome of MINWAs work is the results of two studies that evaluated the e ecti veness of di erent systems, examining the quality of discharges from di erent plants (MINWA, 2009a). Table 7 summarises these results.

Removal capacity

Organic Matt er Phosphorus NitrogenSequencing Batch Reactors 90% 60-90% 20-40%

Sand fi lters 97-98% 60-70% 60%

Trickling fi lters 70-80% 0-32% 0-26%Table 7: E ecti veness of di erent onsite wastewater treatment systems (aft er MINWA, 2009a)

The fi ndings of the studies are interesti ng because they indicate the e ecti veness of di erent treatment techniques. They provide a snapshot of wider on-going research that is bringing a wealth of informati on to understanding the e ecti veness of on-site systems (for further informati on on MINWAs research, readers are directed to: htt p://www.minwa.info/en/research---development).

25


5.4 Good practi ceThe research described provides a brief snapshot into the growing body of knowledge about small-scale and onsite systems. A number of initi ati ves have been set up to develop and share knowledge on aspects of onsite systems, including how to implement a project, likely maintenance requirements and how e ecti ve some modern technologies are. Other projects aim directly at improving the treatment systems in a parti cular area.

5.4.1 Engaging the userA number of good practi ce examples approach the issue of inadequate wastewater treatment by providing demonstrati ons to users to transfer knowledge about e ecti ve wastewater treatment systems. Finland passed a decree in 2003 requiring all onsite wastewater systems to include terti ary treatment to reduce the discharge of nutrients, with any new systems installed to meet requirements and existi ng systems given unti l 2014 to make improvements. In this light a number of work and maintenance demonstrati ons were set up to communicate the technology available to home owners and system users.

MINWA Demonstrati onsMINWA provided informati on on practi cal aspects of e ecti ve treatment systems. The project teamed up with the sustainable development centre of SW Finland (Valonia) to develop a programme of exchanging knowledge and experience of small-scale treatment to encourage positi ve change. A number of work and maintenance demonstrati ons have been published to highlight the processes of installing, operati ng and maintaining on-site systems.

5.4.1.1 Sand fi lter and P removal system installati onThe project demonstrated how to install a wastewater treatment plant for up to 5 populati on equivalent (PE). It used a septi c tank, phosphorus removal unit and sand fi lter to treat all domesti c wastewater (i.e. black and grey waters). The septi c tank and phosphorus removal unit were installed prior to the demonstrati on, fi tti ng the sand fi lter was the main focus. An illustrated publicati on, with an explanati on of how it functi ons was produced and is available at: www.minwa.info/en/installing---maintenance/work-demontrati ons). The system uses sett ling and fi ltering for primary treatment, secondary treatment (and some nutrient removal) in the sand fi lter, with additi onal P removal carried out as a polishing stage. Running costs are for electricity, P removal chemicals, and for periodic sludge removal. The esti mated cost of a full installati on is between 8000 and 10000 .

26


5.4.1.2 Dose-load biochemical system operati onAnother system demonstrated by MINWA was the Raita biochemical plant with chemical dosing. The system is based on a two-part process. Firstly e uent is dosed into a processing tank where biological consumpti on and nitrifi cati on are sti mulated by aerati ng sludge. Secondly P-binding chemicals are dosed into secondary-treated wastewater before sett ling. A proporti on of the sludge is separated for composti ng and e uent undergoes denitrifi cati on before discharging.

The Raita system is suitable for an individual household and uses electronic sensors to measure appropriate ti mes for aerati on, dosing and sludge removal/ e uent discharging. It requires a power supply for these components and also requires maintenance for sludge removal for composti ng (the full demonstrati on can be viewed here: www.minwa.info/en/installing---maintenance/work-demontrati ons).A video was also made of the installati on available from: htt p://www.youtube.com/watch?v=y4YTk15TPwQ&feature=player_embedded.

5.4.1.3 A village wastewater plantMINWA demonstrated a larger treatment system. Clusters (villages) of houses can use a single larger plant, spreading costs, maintenance and responsibility. MINWA produced a demonstrati on of what an individual house requires to channel wastewater to a central system, and what maintenance is required for a plant serving 10 households with biochemical treatment (available here: www.minwa.info/en/installing---maintenance/work-demontrati ons).

Pumping Stati on: In a cluster system, dwellings that cannot rely on gravity-fed sewers use pumping stati ons. A Valonia-led project demonstrated how a pumping stati on is installed to link up an individual dwelling to a village system. It showed the technical requirements and constructi on methods required.

Village Plant Maintenance: Treatment is carried out through three tanks: the fi rst for sett ling out solids, the second for acti vati ng sludge and chemical precipitati on and the third for denitrifi cati on of treated e uent. The demonstrati on highlighted the maintenance requirements of the Goodwell system.

27


Monitoring was explained as essenti al for proper functi oning: measuring pH and oxygen levels, examining soluble P content in e uent, and measuring sludge thickness. Periodic maintenance includes draining the primary tank twice annually, fi lling the tank for chemical precipitati on, and cleaning aerati on plates once every 3-4 years.

5.4.1.4 Maintaining on-site systemsMINWA also commissioned a study that examined the maintenance

of on-site systems from a user perspecti ve for an area in S.W. Finland (Ahti ainen, 2009). It looked at existi ng systems in the region and owners knowledge regarding what maintenance was required and what responsibility the owner had. Di erent treatment technologies were examined from infi ltrati on systems to package plants.The study produced useful results for considerati on in implementi ng a project. Package plants emerged as the most favoured system by users because of their treatment e ecti veness and minimal

maintenance requirements (Ahti ainen, 2009). A number of parti cipants in the study were unsure about various aspects of their systems including what maintenance was required, but voiced an interest in gaining more informati on, and to fi nd out what municipaliti es were doing to improve systems in their area (Ahti ainen, 2009). A common constraint at a number of sites was poor access for sludge removal vehicles, with overgrown vegetati on hiding service points and the poor siti ng of systems at the ti me of installati on making conditi ons di cult for large pumping-vehicles to access (Ahti ainen, 2009).This study is a valuable source of informati on on how to improve the installati on of on-site systems and for highlighti ng some valuable lessons. Understanding constraints and how municipaliti es can achieve best results in a project ar

DRAFT Eutrophication Good Practice Guide

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