luciano de souza ferreira pedro ernesto sales chinelis
TRANSCRIPT
Luciano de Souza Ferreira
Pedro Ernesto Sales Chinelis
The WWTP located in Lauro de Freitas city, Bahia state, Brazildesigned to treat sanitary wastewater from a populationapproximately equal to 1,000 inhabitants (maximum dailyflowrate equal to 8.6 m³ per hour);
13th IWA Specialized Conference on Small Water and Wastewater Systems
Introduction
The characteristics of the anaerobic processes such as low cost,operational simplicity, no energy consumption and lowproduction of solids associated with the favorable environmentalconditions in warm-climate regions have contributed toestablish UASB reactors systems in Brazil.
Therefore, the effluents from anaerobic reactors usually requirepost-treatment to achieve requirements of the environmentallegislation (to complete the removal of organic matter, coliformsand nutrients).
When compared to others wastewater treatment processes, theConstructed Wetlands (CW) present some advantages such as:low construction cost and simplicity regarding O&M;
Introduction
13th IWA Specialized Conference on Small Water and Wastewater Systems
Effluent
1
2
3 4
5
6
7
3 4 Influent
1
2
3
4
5
6
7
UASB Reactor
Slipt Well of Flow
CW with Cyperus alternifolius
CW with Typha sp.
Outlet Well
Pumping Well /
Recirculation Line
Chlorine Contact Tank
Legend
General layout of the wastewater treatment
plant
13th IWA Specialized Conference on Small Water and Wastewater Systems
Objective
To investigate the performance of sub-superficial flow CW asa post-treatment of the effluent from a UASB reactor,operating with total effluent recirculation, by assessing theremoval of organic matter, coliforms and nutrients.
UASB reactor
Split Well of Flow
Dimensions: 3.8 m x 3.8 m with a useful height of 5.1 m
Hydraulic retention time of 8.5 h
13th IWA Specialized Conference on Small Water and Wastewater Systems
Constructed Wetlands
13th IWA Specialized Conference on Small Water and Wastewater Systems
Total Hydraulic Retention Time (days) 1.95
Surface Loading Rate (m³.m-2.day-1) 0.48
Organic Loading Raterange (kg COD. m-2.day-1) 0.05 – 0.11
Nitrogen Loading Raterange (kg TKN. m-2.day-1) 0.007 – 0.03
Phosphorus Loading Raterange (kg P-PO4-3.m-2.day-1) 9.6 x 10-4 – 3.3 x 10-3
Operating Conditions of Constructed Wetlands
13th IWA Specialized Conference on Small Water and Wastewater Systems
Length (m) Width (m) Dept (m)
Inlet zone 3.0 7.0 2.0Planted filter bed 14.0 7.0 0.8Outlet zone 1.0 7.0 1.3
Dimensions of Constructed Wetlands
Schematic section of Constructed Wetlands unit
Physicochemical analyses were carried out according toStandard Methods for Examination of Water and Wastewater(APHA, AWWA, WEF, 2005);
Statistical analyses were performed using Wilcoxon-Mann-Whitney two-sample test at a significance level of 5% using theMinitab software 14®.
Sampling and Analytical Methods
Units
Macrophyte tips Typha sp. Cyperus alternifolius sp.
CW effluentrecirculation
Period withrecirculation
Period withoutrecirculation
13th IWA Specialized Conference on Small Water and Wastewater Systems
The range of COD removal is 52 - 85%;
The range of TSS removal is 60 - 97%.
Results – Organic matter and solids removal
13th IWA Specialized Conference on Small Water and Wastewater Systems
Results – Nutrients removal (TKN and ammonia)
13th IWA Specialized Conference on Small Water and Wastewater Systems
The range of TKN removal is 0 - 40%;
The range of Ammonia removal is 0 - 39% .
Results – Nutrients (phosphorus) and Coliforms removal
13th IWA Specialized Conference on Small Water and Wastewater Systems
The range of Phosphorous removal is 0 - 32%;
The range of Coliforms removal is 0 - 3 log unit.
Results – Maintenance of the CW
Removal of unwanted vegetation ( grass, weed, etc)
13th IWA Specialized Conference on Small Water and Wastewater Systems
Results – Maintenance of the CW
Pruning of the macrophytes (cut Typha sp. and extract Cyperus alternifalius sp) and management of
generated vegetal biomass
13th IWA Specialized Conference on Small Water and Wastewater Systems
Results – Maintenance of the CW
Control of the water level to prevent clogging and hydraulic short circuits
13th IWA Specialized Conference on Small Water and Wastewater Systems
CW are one of the technologies that can effectively treatanaerobically pre-treated UASB reactor effluents;
The recirculation of the CW effluent has not provided aremoval efficiency increase in the parameters analyzed whencompared to stage without recirculation;
The statistical tests showed that there was no significantdifference between the average of the analyzed parameters ofCW planted with Typha sp. and Cyperus alternifolius sp.;
Some characteristics of these macrophytes require attentionduring operation and maintenance activities of the CW.
Conclusions
13th IWA Specialized Conference on Small Water and Wastewater Systems
APHA/AWWA/WEF 2012 Standard Methods for the Examination of Water and Wastewater. 22nd edn. American Public Health Association/American Water Works Association/Water Environmental Federation (APHA, AWWA, WEF), Washington, DC, USA.
Batchelor, A., Loots, P. 1997 A critical evaluation of a pilot scale subsurface flow wetland: 10 years after commissioning. Water Science and Technology 35(5), 337-343.
Brix, H., Arias, C. A. 2005 The use of vertical flow constructed wetlands for on-site treatment of domestic wastewater: new Danish guidelines. Ecological Engineering25, 491-500.
Brix, H., Schierup, H.-H., Arias, C. A. 2007 Twenty years experience with constructed wetland systems in Denmark – what did we learn? Water Science and Technology 56(3), 63-68.
Dahab, M. F., Surampalli, R. Y. 2001 Subsurface-flow constructed wetlands treatment in the plains: five years of experience. Water Science and Technology44(11-12), 375-380.
El-Hamouri, B., Nazih, J., Lahjouj, J. 2007 Subsurface-horizontal flow constructed wetland for sewage treatment under Moroccan climate conditions. Desalination 215, 153–158.
References
13th IWA Specialized Conference on Small Water and Wastewater Systems
El-Khateeb, M. A., Al-Herrawy, A. Z., Kamel, M. M., El-Gohary, F. A. 2009 Use of wetlands as post-treatment of anaerobically treated effluent. Desalination245, 50–59.
Jordão, E. P., Volschan Jr, I., Alem Sobrinho, P. 2009 Secondary WWTP Preceded By UASB Reactors – An Excellent Brazilian Experience. Water Practice and Technology 4(1).
Kaseva, M. E. 2004 Performance of a sub-surface flow constructed wetland in polishing pre-treated wastewater - a tropical case study. Water Research 38, 681–687.
Mandi, L., Bouhoum, K., Ouazzani, N. 1998 Application of constructed wetlands for domestic wastewater treatment in an arid climate. Water Science and Technology 38(1), 379-387.
Mbuligwe, S. E. 2004 Comparative effectiveness of engineered wetland systems in the treatment of anaerobically pre-treated domestic wastewater. Ecological Engineering 23, 269-284.
Vymazal, J. 2005 Horizontal sub-surface flow and hybrid constructed wetlands systems for wastewater treatment. Ecological Engineering 25, 478–490.
References
13th IWA Specialized Conference on Small Water and Wastewater Systems
Thank you for your attention!
Luciano Ferreira
+55 71 99683-2179
Pedro Chinelis
+55 71 [email protected]