Integrated Constructed Wetlands Regulatory Aspects - the EPA’s role Aoife Loughnane Inspector, Environmental Licensing Programme Environmental Protection Agency 28 th June 2011

Presentation Overview EPA view on ICWs Discharge authorisations Types Information required Typical content Example EPA Code of Practice: WWT&D systems serving Single Houses ICW constraints

EPA view on Integrated Constructed Wetlands The EPA supports the concept of ICWs as an option for dealing with low-nutrient effluents provided they are: located in suitable areas following a site suitability assessment; designed, installed and maintained properly; and comply with a discharge authorisation to a suitable receiving water.

Types of discharge authorisation An ICW requires a discharge authorisation prior to construction and operation, either by: (a)Water Pollution Act discharge licence to surface water; (b)Urban Waste Water Discharges; Licence (agglomerations >500 p.e.) Certificate of Authorisation (agglomerations <500 p.e.) (c)IPPC Licence; (d)Waste Licence.

Information required in an application for a discharge authorisation 1.Source, quantity and quality of proposed effluent entering ICW 2.Details of site assessment 3.ICW design & layout 4.Quantity & quality of proposed ICW discharge to receiving waters 5.Details of proposed receiving water Need to demonstrate sufficient assimilative capacity Need to identify potential impacts & mitigation measures

Typical content of a discharge authorisation 1.Quantity & quality of waste water permitted to enter the ICW. 2.Emission limit values for ICW discharge to receiving water. Final effluent quality Discharge rate & volume Period during which a discharge may or may not be made. 3.Monitoring requirements. 4.Reporting requirements.

Glaslough Waste Water Discharge Licence Glaslough village, Co. Monaghan Agglomeration <2,000 p.e. Waste water infrastructure: gravity sewer network, pumping station & associated rising main, treatment of waste water in ICW ICW 5 ponds, combined surface area of approx. 3.4 ha Low permeability in-situ clays (k < 1 x m/s) Design capacity is 1,750 p.e. Current loading is approx. 1,400 p.e. Primary discharge to the Mountain Water River

Glaslough: Emission limits & monitoring requirements ParameterEmission Limit Value (mg/l) BOD10 COD50 Suspended Solids15 Ammonia (as N)1 Orthophosphate (as P)0.5 MonitoringFrequency Primary discharge Flow - continuously BOD, COD, SS, conductivity - monthly Nitrates, Ammonia, Total & ortho-P – quarterly Receiving water (up & downstream) pH, DO, BOD, Ortho-P, Total N, Ammonia - quarterly Lysimeters (effluent percolating through liner) As required by the Agency Ambient groundwaterBiannually

EPA Code of Practice for Waste Water Treatment and Disposal Systems Serving Single Houses (p.e. ≤ 10) Single houses Legal requirement – Building Regulations 2010 CWs can be used to provide: Secondary treatment to effluent from septic tanks, or Tertiary treatment to effluent from packaged WWT systems. Polishing filter should follow CW when discharge route is to groundwater

EPA Code of Practice...ICW criteria for Single Houses CWs should be sealed by a clay liner permeability k ≤ 1.0 x m/s. Design is site specific. Designer & installer must be a competent person. Size is dependent on quality of receiving water Other measures may be added to further enhance treatment All ICWs require periodic maintenance. Guidance EN Small Wastewater Treatment Systems for up to 50PE – Part 5: Pre-Treated Effluent Filtration Systems.

ICW constraints – the EPA’s experience Unsuitable for wastewaters with high nutrient loading Not suitable in all locations Groundwater protection requirements: Minimum of 1m subsoil beneath ponds, Upper 0.5m having a maximum permeability of 1.0 x m/s Greater subsoil thickness required above karstified and sand/gravel aquifers. Phosphorus accumulation in sediments–must be removed periodically High ammonium concentrations in underlying groundwater – risk to nearby receiving waters Planning permission & discharge authorisation required prior to construction and operation.

Integrated Constructed Wetlands Regulatory Aspects - the EPA’s role Aoife Loughnane Inspector, Environmental Licensing Programme Environmental Protection Agency 28 th June 2011