managing wastewater in the city of the future ... · decentralized wastewater and rainwater...

Lettinga Associates Foundation for Environmental Protection & Resource Conservation


Decentralized wastewater and rainwater reclamation and use in Urban Agriculture

Managing wastewater in the city of the future



Decentralized wastewater and rainwater reclamation and use in Urban Agriculture

Session 6. Case studies on sanitation systems for wastewater reuse in urban agriculture. Part 1

Dr. Claudia Pabon Pereirawith contributions from Dr. Adriaan Mels, Dr.Katarzyna Kujawa-

Roeleveld, Dr. Grietje Zeeman



Case studies from the developed world

• The Netherlands• Desar approach

• Black water treatment in Wageningen• Implementation in Sneek

• Other examples for greywater treatment

• Germany• Lübeck-Flintenbreite

• Greenhouse village



Population Netherlands 16.1 million

Households connected to sewer

98.4%

Sewer: total length 86,452 km

Wastewater treatment plants 389

Capacity 33 million p.e.

Wastewater management: facts and figures (2002)

Source: St. Rioned, 2004

The Netherlands

WTP Nieuwveer

Picture: Waterschap Brabantse Delta



Drivers for current ‘hype’

Active role of water boards (STOWA) and interest from sewer people

Desire for INNOVATION in wastewater management Reducing nutrient loads to surface water Increasing attention for presence of pharmaceuticals

and endocrine disrupters in water systems Large sewer renovations at hand Desire to decrease energy consumption Nutrient recycling?



Barriers Calculations for residential areas show that costs are

(still?) significantly higher (both for urine and black water)

Benefits not easily visible

Final use as fertilizer difficult in The Netherlands (too much manure, strict legislation for human excreta)

R&D not finished

Short time line



Current R&D projects in The Netherlands

Transportable urine processing unit (truck) Removal of pharmaceuticals from hospital wastewater Struvite precipitation from mobile toilets Nitrification of urine for sulphide reduction in pressure

sewers Measures to reduce pipe cloggings Effects of urine-fertilization on groundwater

(pharmaceuticals) Concentration of urine by excess ventilation heat at office

level Monitoring established projects Black water digestion



DeSaR concept

struvite precipitation

reuse

discharge

black water

kitchen waste

grey water

UASB-septic

biog

as

nutrient richproduct

Nirogen removal

Removal micro-pollutants/ pathogens (ozone)

sludge

hygienisation

treatment

agricultureRemoval micro-pollutants/pathogens



Grey water Black water

UASB-septicenergy

Post-treatment

N-recovery/removal

Reuse 95L per person

per day

UASB

energy

Post-treatment



Vacuum collection and transport to keep black water concentrated

Digestion for energy recovery at local scale

Use of remaining product as fertilizer (e.g. after composting)

DESAR approach Black water treatment

UASB Septic Tank

Anaerobic treatment of black water and kitchen wastes

7 liters/p.d-1

Different types of septic tanks

Conventional septic tank UASB-septic tankIncreasing sludge

bed height>> HRT

UASBSteady sludge bed height<<HRT

15

Treatment of Black water treatmentComparison :

UASB–STpilot UASB-pilot

7 liters/p.d-1

7 liters/p.d-1

16

Grey water treatment

Anaerobic treatment in a UASB

V= 5 L; HRT= 20 h; 20-30°C

Aerobic treatment sequencing batch

V = 3.6 L; HRT 5 -72 hTemperature = 20-30°C



Present & Future researchSneek, the Netherlands, housing estate of 32 houses;

inhabitants are very much content with the vacuum toilets

DeSaR in Sneek



DeSaR in Sneek

Treatment 32 houses in a garage

Gas collection in a gas bag on the roof



Vacuum collection & transport

use 1 liter for flushing

• Producing 7 l/p.d-1

concentrated black water;

• saving 30-42 l/p.d-1

DeSaR in Sneek

UASB Septic Tank

Anaerobic treatment of black water and kitchen wastes

UASB Septic tank- temperature 25 °C- 2 days liquid retention time- influent COD: 8-10 g/l- effluent COD: 2-3 g/l- gas production 11 m3 CH4 / cap.year



Prototype vacuum kitchen grinder



Black water treatment; struvite precipitation demo scale

24

• Nitrogen and phosphorus ratio: 11 mgN/mgP;

• Molar base : 24 mol N/mol P;

• Applying struvite precipitation with sufficient Mg added, will theoretically result in recovery of almost:

100% of phosphate;

• Only recovery of 1.6 % nitrogen;

• Phosphate recovery: 0.28 kgP/p/y;

•phosphate is an endless resource; good quality phosphate is finished in 40-50 years.



Black water treatment and nutrient recovery

•

25

Black water vacuum toilets

UASB (ST) Struvite(MAP) precipitation

Autotrophic N removal (OLAND) Discharge

to surface water

Final polishing

stabilized sludge (reuse?)

Sludge(return UASB)

CH4

MAP(fertilizer)

N2

Black water vacuum toilets

UASB (ST) Struvite(MAP) precipitation

Autotrophic N removal (OLAND) Discharge

to surface water

Final polishing

stabilized sludge (reuse?)

Sludge(return UASB)

CH4

MAP(fertilizer)

N2

UASB (ST) HRTmin=7d; Tmax = 30oC

Struvite tcontact=30min

OLAND HRTmin=3.5d

?

pathogens



Grey water treatment in constructed wetlands

Six examples in Netherlands and two under construction

Wetlands are integrated in urban design

Treated water is used to create urban ‘waterscapes’

Sometimes treated grey water is used as 2nd quality water



Landscape architects on constructed wetlands

“Constructed wetlands are very interesting for urban design”

“By integrating constructed wetlands in urban design there are hardly any extra costs”

Greywater treatment in constructed wetlands



Urban wasterscape

Constructed wetland

Grey water treatment and reuse in Drielanden, Groningen

EVA Lanxmeer

Constructed wetlands


Lettinga Associates Foundation for Environmental Protection & Resource ConservationEVA Lanxmeer, Culemborg

Double-Houses

Terraced Houses

Ecological Settlement Lübeck-FlintenbreiteExample of urban application: ‘sewerless city’ in Germany

Vacuum station and sewer in Lubeck (Germany) for blackwater; small diameter flexible pipes

Peri-Urban Settlement Lübeck-Flintenbreite (400 inhabitants)Vacuum-Biogas-System for blackwater plus biowaste

(source: Otterwasser GmbH, Lübeck)

Vacuum pipe

Vakuum-toilette

Transport of blackwater and biowaste stormwaterinfiltrationin swales

Greywater treatmentin constructed wetlands

Central technical building

Vacuum-toiletBiowaste-shredder

Digester in basement of community house

Vacuum PumpingStation forBlackwater

Source: Otterpohl

Bio-Waste Inletand Grinder

Constructed wetland for the grey water



Constructed wetlands - examples

Urban environment (Oslo)Rural environment (Sweden)

Palsternackan Stockholm (1995):51 appartementen, 160 bewoners (urine separation)



• This concept is currently more or less realized in one district in Hamburg under the name 'Neues Wohnen in Jennfeld' respectively 'Hamburg Water Cycle in Jenfeld' by Hamburg Wasser (Rebbin, Gerbitz, & Friemert 2007).

Figure 1: Concept of blackwater collection for biogas production, greywater and rainwater collection in sewer system (Meinzinger 2008)

Demonstration toilets in Watermuseum, Arnhem

Urine-Tank; 10 Persons;(Glass-Resin)

•The user acceptance interviews showed a high appreciation of grey water treatment systems (marks between 7.1 and 8.0).•The interviews showed an average lower satisfaction level for vacuum toilets compared to conventional toilets. These results can partially be explained by operational problems in two of the studied locations. Despite of the lower satisfaction, the appreciation was generally high, due to the water saving aspect of vacuum toilets (marks between 7.1 and 8.0 for the cases without operational problems compared to 7.1 for the conventional toilets).•A large part of the respondents with vacuum toilets, i.e. 40-65% of the respondents considers the sound of the flushing unpleasant, compared to 25% of the control group. Noise nuisance is also one of the most commonly mentioned disadvantages of the vacuum toilet system during the interviews.•The maximal sound level of an average vacuum toilet is 12 dB louder than an average conventional toilet (the quietest vacuum toilet has a difference of 10 dB) and is experienced as disturbing by the larger part of the households. •To make the vacuum toilet more acceptable to users the maximal sound production has to be reduced. Based on this investigation various options for reduction appear to be available, such as optimisation of the pipe diameters and sound reducing backplates. The combination of a silencer with a Jets vacuum toilet could result in a vacuum toilet with a maximal sound level that equals the sound of a conventional toilet.



Project (year of realization) Short descriptionKaja – Ås, Norway (1996) 24 student apartments equipped with a vacuum toilet

system and a local grey water treatment system (biofilter + constructed wetland).

Torvetua – Bergen, Norway (1997)

40 single houses equipped with a vacuum toilet system and two local grey water treatment systems (biofilter + constructed wetland).

Wohnen & Arbeiten - Freiburg, Germany (1999)

14 apartments and 4 offices equipped with a vacuum toilet system and a membrane filter system for grey water treatment

Flintenbreite – (2000) 30 houses equipped with a vacuum toilet system and two local grey water treatment systems (constructed wetlands).

Casa Vita – Deventer, The Netherlands (2007)

32 new apartments equipped with a vacuum toilet system

User acceptance of vacuum toilets and grey water systems in The Netherlands, Norway and Germany

Telkamp et al



Wetland systems evaluation

DriversThe perception and opinion of neighborhood dwellers about the systems was generally positive. Most people enjoy the estheticallandscape element of the systems and the presence of water in their surroundings. Most interviewed users feel that these systemscontribute positively to environmental awareness. Some of the drivers for the implementation were water saving. Reduction of wateremissions, protection of surface water.The fact that the systems generally have a low maintenance requirement and low operational costs are also important for the highdegree of satisfaction.BarriersThe main barriers identified during the decision making process in the pilot cases are decentralize maintenance because of theresponsibilities it implies for users, restriction in cleaning products and higher investment cost. In the cases located in Kaja, Tovertuaand Flinterbreite there were no significant barriers during the decision making process. Some barriers have been evidenced duringoperational stage, such as lack of support by the governmental authorities to reduce the fees.

•In The Netherlands: Het Groene Dak , Polderdrift, Drielanden, De Waterspin •In Sweden: Kaja and Tovertua•In Germany: Flinterbreite

Comparative performance of constructed wetlands for decentralized treatment of grey water in the Netherlands, Germany and Norway

These cases showed that the implementation of on-site grey water treatment systems combined with reuse of reclaimed water may lead up to 57% less drinking water consumption. The treatment performance of the wetlands was generally satisfactory, although a number of the studied systems did not monitor properly the systems due to high costs this imply and some operational difficulties with clogging because of inadequate maintenance. People perception of constructed wetlands is positive, health risk is inexistent and different schemes of management and operation can be implemented.

0% 20% 40% 60% 80% 100%

Wageningen (conventional toilet)

Kaja

Torvetua

Wohnen & Arbeiten

Flintenbreite

Casa Vita

very satisf ied

satisf ied

neutral

dissatisf ied

very dissatisf ied

7.1

4.4

7.8

6.6

7.2

8.0

7.1

7.4

7.1

7.5

0 1 2 3 4 5 6 7 8 9 10

Wageningen

Kaja

Torvetua

Wohnen & Arbeiten

Flintenbreite

Casa Vita

combined grey w ater system and vacuumtoilet

conventional toilet

grey w ater treatment

vacuum toilet

Average marks given by the households for the vacuum toilets and / or grey water systems in the various projects

Average marks given by the households for the vacuum toilets and / or grey water systems in the various projects

Figure 1. Level of satisfaction of households with their vacuum toilet systems compared to a control group with conventional toilets (Wageningen

0% 10% 20% 30% 40% 50% 60% 70% 80% 90%

Wageningen (conventional toilet)

Kaja

Torvetua

Wohnen & Arbeiten

Flintenbreite

Casa Vita

Percentage of interviewed households that considers the flushing sound of their toilet unpleasant

User acceptance of vacuum toilets and grey water systems in The Netherlands, Norway and Germany

Greenhouse village (http://www.zonneterp.nl/zonneterp.pdf )

Technical lay-out of Greenhouse VillageA.R. Mels, N. van Andel, E. Wortmann, J. Kristinsson, P. Oei, J. de Wilt and G. Zeeman (2006)

http://www.zonneterp.nl/zonneterp.pdf�

Climate control system of the greenhouse and the housing blockA.R. Mels, N. van Andel, E. Wortmann, J. Kristinsson, P. Oei, J. de Wilt and G. Zeeman (2006)



The carbon cycle of Greenhouse VillageA.R. Mels, N. van Andel, E. Wortmann, J. Kristinsson, P. Oei, J. de Wilt and G. Zeeman (2006)



Separate collection and treatment of black and grey water in Greenhouse VillageA.R. Mels, N. van Andel, E. Wortmann, J. Kristinsson, P. Oei, J. de Wilt and G. Zeeman (2006)



The water system of Greenhouse VillageA.R. Mels, N. van Andel, E. Wortmann, J. Kristinsson, P. Oei, J. de Wilt and G. Zeeman (2006)



The nitrogen balance of Greenhouse VillageA.R. Mels, N. van Andel, E. Wortmann, J. Kristinsson, P. Oei, J. de Wilt and G. Zeeman (2006)



Environmental costs and benefits in Greenhouse VillageA.R. Mels, N. van Andel, E. Wortmann, J. Kristinsson, P. Oei, J. de Wilt and G. Zeeman (2006)



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