Dr Kiran Tota-Maharaj Senior Lecturer in Water & Environmental Engineering, University of Greenwich, UK Dr Denver Cheddie Associate Professor in Mechanical Engineering, University of Trinidad and Tobago

SE islands of Antilles, situated between 10° 2' & 11° 12' N latitude and 60° 30' & 61° 56' W longitude. At the closest point, Trinidad is just 11 km off the Venezuelan coast. Agricultural products include citrus, cocoa, coconuts and other products. Recent growth has been fueled by investments in liquefied natural gas, petrochemicals, & steel. It is the leading Caribbean producer of oil and gas, and its economy is heavily dependent upon these resources but it also supplies manufactured goods, notably food and beverages, as well as cement to the Caribbean region. Oil & gas account for 40% of GDP & 80% of exports, but only 5% of employment. Trinidad & Tobago

Outline The Caribbean Coconut Industry Flooding in Rural Caribbean Communities Storm water filtration Purpose of research Filters analysed Results

Green Coconuts Water & Jelly (Gelatinous inner part) Consumption Waste Product sent to Landfills Brown/mature coconut produces fibres Dry coconuts used to make several nutritious foods & beverages

Surface Water Flooding Problems Trinidad and Tobago 2 seasons – dry and wet Wet season characterised by flash flooding Flood waters contain pollutants Water supply to rural communities come from surface water

Stormwater Filters Source control approach to flood waters Filters remove pollutants Improves water quality Schematic of Typical Sand/Gravel Filter for stormwater management across the Caribbean

Stormwater Filters Typical filters are expensive for rural Caribbean communities Clog easily and requires periodic backwashing and maintenance Several communities across Trinidad and Tobago have not adopted Sustainable Drainage Systems

Purpose To produce low cost stormwater filters constructed from readily available materials (Coconut Husk/Fibres) To apply Low-impact development (LID) practices through sustainable waste management techniques To alleviate Flash flooding & Urban Flooding across Small Island Developing States (SIDS) through the applications of Sustainable Drainage Systems (SuDS)

Three (3) Stormwater Filters Investigated ASCE/ US EPA (2000). Determining Urban Stormwater Best Management Practice Removal Efficiencies. ASCE/US EPA Database. International Stormwater Best Management Practices (BMP) Database

Three (3) Stormwater Filters Investigated

Stormwater Sampling & Analysis Obtained from 2 villages in Trinidad Quantity MeasuredHow Measured pHThermo scientific Orion 3 star branch top meter Chemical Oxygen Demand (COD) Hach DRB200 reactor block and DR500 spectrophotometer Nitrates / NitritesSpot sampling PhosphatesSpot sampling Total suspended solids (TSS) Filtration method Total dissolved solids (TDS) Evaporation method TurbidityTurbidity meter ConductivityJenway 4520 conductivity meter ColiformsMembrane filter technique APHA, AWWA, WEF. Standard Methods for examination of water and wastewater. 22nd ed. Washington: American Public Health Association; (2012)

Results Filter (1) Coconut Husk/Fibres & Gravel Media Filter (2) Sand & Gravel Media Filter (3) Pea gravel, Gravel & Coconut Husk/Fibres Media January- December 2014 (Sample number n = 190)

Results Comparison of bacterial (total coliforms) survival versus time for stormwater filters 1- 3, (Sample number n = 45, January-June 2014) Filter (1) Coconut Husk/Fibres & Gravel Media Filter (2) Sand & Gravel Media Filter (3) Pea gravel, Gravel & Coconut Husk/Fibres Media

Results Cont’d Filters significantly reduce nitrates, nitrites, TSS & TDS High removal rates for coliform levels Relatively good reduction in COD (20-70 %), phosphates (10 %), turbidity (30-60 %) There were no significant differences in water quality effluents for all three filters (p > 0.05, according to ANOVA) Filters performed well in treating water & producing cleaner effluent water for non-potable purposes (water recycling e.g. washing cars, agriculture etc.) No clogging noticed during one-year period of operation

Conclusion Coconut fibre filters are good for improving the quality of stormwater treatment & urban runoff control especially during the rainy season (July-December) Results from water quality analysis found the water outflows from filters were not applicable for drinking purposes (according to WHO) Filters are low cost & disposable (eventually sent to Landfills or used in alternative applications) No need for backwashing Viable source control approach to stormwater pollution

Acknowledgements Thank you for listening. The research was supported by The University of Trinidad & Tobago, Point Lisas Campus, Trinidad, West Indies. The authors would like to acknowledge Professor Mahendra Thakur (recently retired Professor) from the Department of Mechanical Engineering, University of Trinidad and Tobago for supporting this research initiative. We would also like to thank the technical staff within the Department of Utilities Engineering in the University of Trinidad and Tobago for their support in carrying out the experimental project work.