Humberto Carlos Ruggeri Frederico de Almeida Lage Filho Mônica Medeiros Roque Passos Piveli Utilization of Shallow Ponds for Ammonia Nitrogen Removal from Facultative Pond Effluent 8th IWA Specialist Group Conference on Waste Stabilization Ponds - Belo Horizonte/MG, April 2009

State of the Art Ponding Systems can be economically feasible alternatives regarding wastewater treatment in developing countries & small communities. There are hundreds of ponding systems in operation in Brazil, however there is a lack of predictive models for ammonia N.

Introduction Ammonia N removal can take place by means of three processes: Ammonia stripping to the atmosphere Ammonia assimilation by algal biomass Biological Nitrification. Several researchers (e.g. Yánez) have reported that ammonia N removal via nitrification in photosynthetic ponds is NOT SIGNIFICANT.

Introduction (cont.) Pano & Midlebrough (1) associated ammonia N removal in ponds with: surface hydraulic loading rate, the depth, pH and temperature – they recognized volatilization as the main mechanism. Yánez (2) associated ammonia N removal to the TKN and BOD loading rates and stablished an experimental model.

Objective  To investigate which type of connection there is between ammonia N loading rate and ammonia concentration in the maturation pond final effluent An in parallel look: possible effects of the pond depth and stripping to atmosphere.

Experimental Setting - Intro Experimental Field Station owned by SABESP, located in the municipality of Lins, SP. Agricultural reuse of treated sewage. Real scale treat// system treats domestic sewage generated by 65,000 inhabitants: anaerobic pond followed by facultative pond

Experimental Setting Facultative pond effluent fed to tertiary treatment pilot ponds.

Experimental Setting (cont.) Two pilot scale ponds - 8 m long and 2 m wide. Chicane: L/W = 16/1

Experimental Results  Operating Conditions: HRT PHASE 123 H = 0,5 mH = 1,0mH = 0,5 mH = 1,0mH = 0,5 mH = 1,0m ,515

Results  Phase 01 – (HRT = 5 days)‏

Historical Data Series, Box-Whisker Diagram for Ammonia N (1st Phase )

Results  Phase 02 – (HRT =10 days)‏

Historical Data Series, Box-Whisker Diagram for Ammonia N (2nd Phase)

Results  Phase 03 – (HRT D-1,0m =15 days; HRT D-0,5m = 7,5 days)‏ (Same surface area and flowrate)

Historical Data Series, Box-Whisker Diagram for Ammonia N (3rd Phase)

Results  Comparison between phases Alkalinity Dissolved Oxygen

Results  Comparison between phases pH Temperature

Results  Comparison between phases Total BOD Total COD

Results  Comparison between phases Ammonia N TKN

Conclusions  The experimental results so far have shown the feasibility of ammonia N removal by means of tertiary complementary ponds, and the influence of pond depth.  Experimental results from subsequent phases should lead to treatment conditions that are necessary to obtain tertiary pond effluents with target ammonia N levels.