1 IWA Specialized Conference on Small Water and Wastewater Systems Athens 14-16 September 2016. The past, the present and the future for Small Water and Wastewater Systems Hallvard Ødegaard * Prof. em. Norwegian University of Science and Technology (NTNU) CEO Scandinavian Environmental Technology (SET) AS hallvard.odegaard@ntnu.no SET AS
2 The origin of the IWA Specialist group on Small Water and Wastewater Systems (SWWS) • 1989 – 1’st conference in Trondheim (NTNU), Norway « Design and operation of small wastewater treatment plants» • 1989 – HØ took the initiative to form an IWA Specialist Group on the subject • 1991 ‐ Accepted by the IWA Governing Board • 1993 – 2’nd conference in Trondheim (NTNU), Norway • 1995 – 3’rd conference in Kuala Lumpur, Malaysia Originally the group was focusing on small communities (100 ‐ 2000 pe) and industries – not on on ‐ site plants (single house or small group of houses) – even though papers on on ‐ site solutions were also included SET AS
3 The history of the IWA SWWS Specialist Group Nr Year Conference Conf. organizer MC chair Developments – conference topics 1 1989 Trondheim, Norway H. Ødegaard, NTNU H. Ødegaard Design and Operation of small wastewater treatment plants 2 1993 Trondheim, Norway H. Ødegaard, NTNU H. Ødegaard Design and Operation of small wastewater treatment plants 3 1995 Kuala Lumpur Kumarasiwam (Malay.) + H. Ødegaard Design and Operation of small wastewater treatment Malaysia MC, SWWTP plants 4 1999 Stratford ‐ upon ‐ Avon, P. Wilderer, TUM P. Wilderer Small wastewater treatment plants UK 5 2002 Istanbul, Turkey I. Öztürk, ITU G. Ho Small water and wastewater systems 6 2004 Perth, Australia K. Matthew, Murdoch Univ. G. Ho On ‐ site Wastewater Treatment and Recycling 7 2006 Mexico city, Mexico S. Gonzales, UNAM S. Gonzales 7’th on Small water and wastewater systems 8 2008 Coimbatore, India J.V. Thanikal, KCT (chair) S. Gonzales 8’th on SWWS, 2’nd DEWSIN M. Torrijos, NIAS (co ‐ chair) 9 2010 Girona, Spain J. Colprim Galceran, S. Gonzales Sustainable solutions for SWWS and 2’nd on Resource LEQUIA oriented Sanitation, ROS (EcoSan) 10 2011 Venice, Italy F. Cecchi, F. Fatone Univ. of K. Matthew 10’th on SWWS, 4’th on DEWSIN, 3’rd on ROS Verona 11 2013 Harbin, China G. Xu , HIT K. Matthew Small and Decentralized W & WW Treatment System and Sludge management 12 2014 Muscat, Oman J.V. Thanikal, CCE K. Matthew 12’th on SWWS and 4’th on ROS 13 2016 Athens A. Andreadakis, K. Matthew 13’th on SWWS and 5’th on ROS M. Simos, NTUA SET AS
4 Terminology/Characterization of SWWS By size or flow (pe connected/m 3 d ‐ 1 ) • – Mini systems (MS) or on ‐ site systems (1 ‐ 10 families – 1 ‐ 50 pe) – Small, small systems (SSS) (50 – 500 pe) – Medium small systems (MSS) (500 – 2000 pe) – Large small systems (LSS) (2000 – 10000 pe) Infiltration systems Small community plants Pre ‐ fabricated Pond systems Constructed wet ‐ lands On ‐ site built • By degree of centralization – Decentralized (normally MS to SSS) – Semi ‐ centralized (normally MSS to LMS) – Centralized (normally SSS to LMS) • By technology concept – Nature ‐ based (Eco ‐ San) • Infiltration systems, ponds, constructed wetlands, etc – Technology ‐ based (traditional WWTP) • Mechanical, chemical, biological, biological/chemical etc – Combinations of technology ‐ and nature ‐ based (e.g. nature based polishing) SET AS
5 What I will address As the specialist group from the start was focusing on small communities (100 ‐ 2000 pe) and industries – not on on ‐ site plants, I will primarily discuss concepts for: 1. Technology ‐ based small wastewater treatment plants – In the past (activated sludge, trickling filter, RBC) – In the present (MBBR ‐ moving bed biofilm reactors) – In the future (advanced treatment for reuse) 2. Small technology ‐ based drinking water treatment plants – Microbial barrier analysis – Biological treatment for Fe and Mn i groundwater – Ozonation/biofiltration for NOM ‐ removal in surface water 3. Semi ‐ centralized reuse systems – A smart water community water management system – Grey ‐ water and storm ‐ water treatment SET AS
6 The past SET AS
7 My introduction to Small Wastewater Treatment Plants 1969: MSc ‐ thesis on chemical treatment of ww 1971: In the army – experiments on small wwtp (70 pe) 1972: Wrote: Guideline on Prefabricated WWTP’s Simultaneous precipitation Fe, Al SET AS
8 The dominating treatment obtions for SWWTP in Norway in the 80’ies Recommendations for SWWTP (< 500 pe): Utilizing reactor volumes for equalization Ødegaard, 1987 SET AS
9 Comparisons of efficiencies among 387 small (< 2000 pe) WWTP’s in Norway, 1996 (Ødegaard and Skrøvset, 1997) % of plants lower than % of plants lower than % of plants lower than 14 Chemical plants 98 Chemical plants 29 Biological plants 49 Biological plants 194 Biological/ 108 Biological/ chemical plants chemical plants Effluent concentration, COD (g/m 3 Effluent concentration, COD (g/m 3 Effluent concentration, BOD (g/m 3 % of plants lower than % of plants lower than 99 Chemical plants 63 Chemical plants 39 Biological plants 34 Biological plants 201 Biological/ 147 Biological/ chemical plants chemical plants Effluent concentration, Tot P (g/m 3 Effluent concentration, SS (g/m 3 SET AS
10 Biological chemical plants (Ødegaard and Skrøvset, 1997) SET AS
11 The present SET AS
12 The moving bed biofilm reactor (MBBR) The MBBR concept may be used in different ways: • Pure MBBR systems Carrier filling fraction o anything from 0% to 65 % Commonly : o 60 ‐ 65 % in aerobic 55 ‐ 60 % in anoxic • Hybrid activated sludge/ biofilm systems (IFAS) : 55 ‐ 60 % in aerobic 50 ‐ 55 % in anoxic o Mostly used for upgrading of activated sludge plants SET AS
13 Typical small (< 500 pe) MBBR plant in Norway Precipitant Pre ‐ treatment, sludge storage Flocculation and equalizing volume and settling In Out Manifold for desludging SET AS
14 Responses to varying load and temperature Geilo secondary MBBR plant (mountain tourist resort) Flow m 3 /d 4500 BOD, mg/l 4000 In 1000 3500 3000 Influent 2500 800 2000 1500 600 1000 500 400 0 Flow, m3/h 200 Min Max 250 0 200 150 100 50 BOD, mg/l Ut Bio (filt) Utløp 0 25 Effluent Temp, o C ( ) Temp bio 20 15 15 12 10 9 6 5 3 0 0 SET AS
15 MBBR ‐ experiences Nitrification • Nitrification rate strongly influenced by DO BOD ‐ and P ‐ removal Coag. • Always at least two MBBR’s in series • Combine with coagulation • MBBR HRT: 0,5 – 1,5 hr N ‐ removal Denitrification • High DN ‐ rates with external carbon sources Carbon. Coag. 5 Denitrification rate, g NO 3 -N/m 2 /d Ethanol Methanol 4 Monopropylene glycol 3 2 1 • Combined pre ‐ and post ‐ DN (for high N ‐ removal) 0 gives great flexibility in operation 3 5 7 9 11 13 15 17 Temperature, °C • MBBR HRT: 3 ‐ 4 hrs Rusten et al, 1996 SET AS
16 SWWS on cruise ships (Ex. Scanship MBBR plant) Water & waste facilities • Up to 6000 persons served • Effluent requirements: • BOD<15, SS<10, NH 4 ‐ N<3, TN<10; E ‐ Coli ND • Sludge and waste incineration SET AS
17 Membrane bioreactors Distribution of MBR plants in Europe per capacity (m 3 /d) and suppliers Configurations Lejeans et al, 2010 Challenges Suitability for small wwtp • • Pre ‐ treatment Requires : • • Membrane: Good pre ‐ treatment • • Fouling Close surveillance • • Clogging Skilled operators • • Ageing High energy demand • • Integrity Conservative design • Energy requirement SET AS
18 In your experience, what are the main technical issues or limitations that prevent MBRs working as they should? http://www.thembrsite.com/features/2015 ‐ mbr ‐ survey ‐ results/ SET AS
19 Average power consumption of The energy challenge MBR system in Japan 0.70 Other equipment Power consumption [kWh/m 3 ] 6 RAS pumping Specific Energy Demand (kWh/m 3 ) MBR A (Zenon) 1,440 m3/d 5 Mixing in anoxic MBR B (Puron) 14,250 m3/d MBR C (Puron) 1,750 m3/d Permeate pumping MBR D (Zenon) 3,000 m3/d 4 Aeration 3 blower 2 0.42 1 0 0% 20% 40% 60% 80% 100% Utilisation Capacity (Real flow / Nominal flow) Anoxic tank + Aerobic MBR Flux 0.8 m/d (33 l/m 2 h) Source: 4 MBR operated by Veolia in France Lejeans et al, 2010 Watanabe, 2014 SET AS
20 Membrane filtration after MBBR Different strategies: a. Direct membrane filtration b. Membrane filtration after primary separation c. a. MBBR – Discfilter – Contained hollow fiber MBBR – submerged hollow fiber UF UF membrane membrane Sewer mining by MBBR ‐ MBR (Darling Walk, Sidney, AUS) b. d. MBBR – submerged membrane MBBR – DAF – Contained hollow fiber UF in reactor with settling zone membrane SET AS
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