% Molybdate Reactive Phosphorus of Total Phosphorus in Urban Wastewater Influents and Effluents in County Cork Agglomerations >2000 P.E A. Costello M.Sc. 2009 % Molybdate Reactive Phosphorus of Total Phosphorus in Urban Wastewater Influents and Effluents in County Cork Agglomerations >2000 P.E by Alan Costello B.Sc. Submitted in part fulfillment of the HETAC requirements of the award of Master of Science in Environmental Protection At Institute of Technology, Sligo September 2009 Supervised by: Eamonn Grennan Page I of 154 Abstract Phosphorus is a key nutrient in freshwater ecosystems as it is well known to cause severe water quality problems when enrichment with phosphorus occurs, a phenomenon known as eutrophication. Legislative measures are in place to control or limit the amount of phosphorus discharged, and there are several physical, chemical and biological treatment processes used to remove or reduce phosphorus prior to discharge. Whether or not rural developments are granted planning permission in Ireland is often contingent on the levels of phosphorus in the receiving waters it is proposed to discharge treated effluent to. Several forms of phosphorus exist in environmental monitoring; the most often encountered is the inorganic form usually known as orthophosphate. However, there are other names used for this inorganic form, depending on the method of analysis, such as soluble reactive phosphorus (SRP), molybdate reactive phosphorus (MRP), dissolved reactive phosphorus (DRP), leading to confusion and misinterpretation of results. The presentation of analytical data also leads to confusion when the results’ form is not clearly expressed. Average wastewater influent total phosphorus levels for County Cork’s wastewater treatment plants vary considerably. Average phosphorus loadings were in the range 2.3 to 14.2 mg/1 TP-P, although a more reliable upper end of the range for average influent TP-P in Cork is Ballincollig with 11.6 mg/1 TP-P. Average influent MRP ranged from 1.6 mg/1 to 7.6mg/l PO4-P. Average MRP% of the total phosphorus ranged from 43.5% to 68 %. Disregarding effluents where phosphorus removal measures are required under the Urban Waste Water Treatment Regulations, 2001, average effluent concentrations of total phosphorus ranged from l.lmg/1 at Kanturk to 6.4mg/l TP-P at Ballincollig. Average effluent concentrations of MRP ranged from 0.9 to 4.6mg/l PO4-P. The range of % MRP of the total phosphorus was greater in plants where phosphorus removal technologies were employed, 34.4% to 91.7%. Plants without additional phosphorus removal had a narrower range, 62.4% to 87.1%. Page 2 of 154 Acknowledgements Caroline for her support and encouragement, Evelyn and Tom for their ability to distract. Valerie, Maureen, Sylvain, Sarah and Seamus for their assistance in collecting samples and offering advice/assistance on the analytical side. My employer, Cork County Council, particularly Louis Duffy as Director of Service, Environment, whose approval allowed me the opportunity to complete the M.Sc. Eamonn Grennan for his supervision, advice and constructive criticisms often in the face of unrelenting misplaced full stops and brackets. Page 3 of 154 Table of Contents Page. Abstract 2 Acknowledgements ...................................................................................................... 3 Table of Contents ...................................................................................................... 4 Table of Figures ...................................................................................................... 6 Table of Tables ...................................................................................................... 7 1 Introduction to Project......................................................................................8 1.1 Project Objectives...................................................................................................... 8 1.2 Project A im s................................................................................................................... 9 1.3 Dissertation Structure..................................................................................................11 1.4 Study Area: County C ork........................................................................................... 13 2 Introduction to Phosphorus............................................................................18 2.1 Phosphorus....................................................................................................................18 2.2 Phosphorus Rocks and Minerals............................................................................... 19 2.3 Phosphorus Extraction and Beneficiation.............................................................. 20 2.4 Biochemical Phosphorus............................................................................................27 2.5 Phosphorus Applications............................................................................................28 2.6 Sodium Tripolyphosphate & Detergents.................................................................29 3 Phosphorus Sources and the Phosphorus Cycle.......................................... 31 3.1 Phosphorus Cycle........................................................................................................ 31 3.2 Phosphorus in Aquatic Systems................................................................................32 4 Phosphorus and its impacts on the Environment........................................ 35 4.1 How Does Phosphorus get into water?...................................................................35 4.2 Eutrophication..............................................................................................................39 4.3 How best to eliminate eutrophication caused by phosphorus:.......................... 41 5 Phosphorus and Irish and European Legislation...................................47 5.1 Water Quality Standards, Europe, Ireland and Phosphorus Legislation 47 5.2 Local Government (Water Pollution) Act, 1977; (Water Quality Standards for Phosphorus) Regulations, 1998) S.I. No. 258 of 1998............................... 51 5.3 The Water Framework Directive.............................................................................. 56 5.4 EC Directive 91/271/EEC (Urban Wastewater Directive)................................. 60 5.5 Waste Water Discharge (Authorization) Regulations 2007 (S.I. No. 684 of 2007)..............................................................................................67 6 Wastewater Treatment and Phosphorus Removal.....................................68 6.1 Phosphorus in wastewaters........................................................................................ 68 6.2 Phosphorus species in sewage...................................................................................70 6.3 Phosphorus Removal...................................................................................................72 Page 4 of 154 6.4 Chemical Precipitation............................................................................................... 73 6.5 Physical Phosphorus removal....................................................................................76 6.6 Biological Phosphorus Removal...............................................................................77 6.7 Enhanced Biological Phosphorus Removal.............................................................79 7 Monitoring Phosphorus...................................................................................82 7.1 Introduction to phosphorus monitoring................................................................... 82 7.2 Phosphorus Species.....................................................................................................84 7.3 Laboratory Analysis....................................................................................................89 8 Materials and Method......................................................................................90 8.1 M aterials........................................................................................................................ 90 8.2 Total Phosphorus and Molybdate Reactive Phosphorus: Methods and Procedures..........................................................................................92 8.2.1 Total Phosphorus M ethod..........................................................................................92 8.2.2 Total Phosphorus Procedure......................................................................................94 8.3.1 Molybdate Reactive Phosphate Method..................................................................96 8.3.2 Molybdate Reactive Phosphate Procedure............................................................. 97 9 Results ..................................................................................................... 99 9.1 Ballincollig W W TP...................................................................................................101 9.2 Bandon WWTP..........................................................................................................103 9.3 Blarney WWTP......................................................................................................... 105 9.4 Castlemartyr WWTP................................................................................................ 107 9.5 Charleville WWTP....................................................................................................109