the reuse of grey water in buildings
TRANSCRIPT
The reuse of grey water in buildings
METROPOLITANA
MILANESE SPA
Sabino DE GISI, Patrizia CASELLA, Roberto FARINA
Framework
• Introduction
• Towards a Resource Oriented Sanitation Approach
• Objective of the study
• Gray water (GW) quality
• Guidelines for Grey Water reuse
• Technologies for Grey Water treatment and reuse
• Case studies
• Case 1: klosterenga, Oslo, Norway
• Case 2: Preganziol, Treviso, Italy
• Case 3: Bologna, Italy
• Case 4: Berlin-Kreuzberg, Germany
• Where the reuse is essential (Some remarks of the Zero Project)
• Conclusions
• References
Introduction
• Generally, segregation of domestic sewage into black water and grey water components should be regarded as a significant outcome of new conceptual developments concerning waste as a resource;
• This involves a change in the conventional end of pipe approach currently used to the present day;
• An open challenge in the water & wastewater sector, refers to the upgrading of the sewerage system of cities with a great investments for governments all over the world;
• In some cases, the adoption of a «Resource Oriented Sanitation Approach» may be the most suitable solution in terms of technical, environmental and economic aspects.
Open issues
Resource Oriented Sanitation
• It’s the case of the Hamburg Water Cycle (HWC), an innovative and integrated concept for wastewater treatment and energy generation;
• The HWC has been developed by Hamburg’s water supply and wastewater utility Hamburg Wasser, with around 610 connected households for about 2000 inhabitants;
• It is the largest demonstration of the resource-oriented sanitation in Europe.
Open issues
CITY OF HAMBURG
CITY OF HAMBURG
Resource Oriented Sanitation
Integrated approach for Water & Energy
• The concentrated blackwater and additional biomass will utilized for biogas production in a district anaerobic digester;
• Biogas will be used for the generation of carbon neutral heat and electricity in a combined heat and power plant;
• Grey water, from showers, sinks, etc., will be treated in decentralized system;
• Local rain water management closes the natural water cycle.
The objective
In this context, the aim of work is to describe the state of the art of:
• Grey water characteristics;
• Guidelines for grey water reuse.
Identifying, subsequently, the:
• Appropriate technology solutions.
These goals are pursued by means of several case studies.
Grey water quality
• With reference to a residential home, we have the following fluxes:
Bathroom Laundry Kitchen Dishwasher
Mixed
Types of grey water and production [L/person/day]
• With reference to the production, the typical volume of grey water varies from 90 to 120 L/person/day.
• While, for low income countries with water shortage, the production is about 20 – 30 L/person/day.
1
Grey water quality100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
2500
2600
2700
2800
2900
30000
COD
BOD5
Bathroom Laundry Kitchen Dishwasher
TSS
Mixed grey water
Parameter
Concentration
[mg/L]
Organic matter & total suspended solids
Kitchen grey water and laundry
grey water are higter in both
organics and TSS!
1
Grey water quality2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
22.5
25.0
27.5
30.0
32.5
35.0
37.5
40.0
42.5
45.0
47.5
50.0
52.5
55.0
57.5
60.0
62.5
65.0
67.5
70.0
72.5
75.00.0
TN
TP
Parameter
Concentration
[mg/L]
Nutrients (NTOT & PTOT)
Bathroom Laundry Kitchen Dishwasher Mixed grey water
171
1
Grey water quality
C:N:P ratio and biodegradability
• All type of grey waters show good biodegradability in terms of COD:BOD5
ratio;
• Compared to the suggested COD:N:P ratio of 100:20:1, bathroom grey water, laundry and mixed ones are deficient in nitrogen.
Bacterial load & pH
1
Guideline for GW reuse
Wastewater reuse standard
• Today, very few reuse guidelines are particularly made for grey water recycling.
2
Guideline
Types of reuse
Toilet flushing Irrigation Washing
A: Germany (1999)
B: China (2006)
C: USA (2007)
D: Japan (1996)
E: Australia (2003) Regardless of the type of use
Wastewater reuse standards: Values
Guideline for GW reuse2
Technologies
Technologies for grey water treatment and reuse
• Technologies for grey water treatments include physical, chemical and biological systems.
• As reported in Li et al. (2009), most of these technologies are preceded by a solid-liquid separation step as a pre-treatment and followed by a disinfection step as post treatment.
• To avoid the clogging of the subsequent treatment, the pre-treatments such as septic tank, filter bags, screen and filters are applied to reduce the amount of particles and oil and grease.
• While, the disinfection step is used to meet the microbiological requirements.
3
Pre-treatment DisinfectionTechnologyGrey water To reuse
Oil and grease Particles
Disinfectant
Technologies
Technologies for grey water treatment and reuse
3
Physical processes
Technologies
Cartridge filter
Chemical processes Biological processes
Filtration
Screening + Sedimentation + disinfection
Membranes (UF, NF, RO)
Filtration + Activated Carbon + Sand filter + Disinfection
Electro-coagulation + Disinfection
Coagulation + Sand filtration + GAC
Coagulation with aluminium salt
Magnetic ion exchange resin
Sedimentation + RBC + UV Disinfection
Screen + RBC + Sand filtration + Chlorination
Membrane Biological Reactor (MBR)
UASB (upflow anaerobic sludge blanket reactor)
Constructed wetlands
Sequencing Biological Reactor (SBR)
Technologies3
Parameter
Guideline/Percentage removal
BOD
COD
TN
TP
TSS
Torbidity
T. Coliform
F. Coliform
pH
256.5
400.0
18.0
11.5
104.0
202.0
4.0∙107
7.2
<Value>
7.5∙107
A
5
<100/ml
< 10/ml
(for Toilet flushing)
98.1%
99.9%
99.9%
% Removal B
10
< 3/100 ml
96.1%
97.5%
99.9%
% Removal
5
10 44.4%
6 - 9
10
< ND/100 ml
96.1%
100.0%
C % Removal
99.0%2
Guidelines: A = Nolde (1999), Germany; B = Ernst et al. (2006), China; C = Asano (2007), USA
Average Mixed Grey water
Technologies for grey water treatment and reuse
Technologies3
Guideline
A
B
C
(98.1%)
BOD TN Torbidity T. Coliform Considerations
Guidelines: A = Nolde (1999), Germany; B = Ernst et al. (2006), China; C = Asano (2007), USA
Mixed Average Grey water
Technologies for grey water treatment and reuse
F. Coliform
(99.9%) (99.9%)Need to remove BOD > 98% and bacterial load (> 99%)
(96.1%) (99.9%)(44.4%) (97.5%)Need to remove BOD > 96%, TN > 44%, Torbidity > 97% and F. coliform (> 99%)
(96.1%) (100%)(99.0%)Need to remove BOD > 96%, Torbidity > 99% and F. coliform (> 99%)
(for Toilet flushing)
Organic Matter Nitrogen Torbidity Bacterial load
Degree of removal (High; Moderate; Low)
High Moderate High High
(for Toilet flushing)
We need to remove Torbidity (>90%), Organic matter (>95%), Nitrogen (> 40%)and microbiological parameters (>99.9%)
Technologies3
Which processes allow to obtain these removals?
Processes
Cartridge filter
Screening + Sed. + Disinfection
BOD TN Torbidity T. Coliform Is it good?F. Coliform
(99.0%)
(54.4%) -(37.3%) (15.0%)
(55.9%) -(48.6%) -
-
-
(66.7%)
NF membrane
RO membrane
Filtration + Activated Carbon + Sand filtration + Disinfection
(93.4%) - -
(97.7%) -- (100%)
(31.4%) -(53.8%) -
-
-
- (96.7%)
UF membrane
(94.9%) -(85.7%) --
Sed. + RBC + UV disinfection
Screen + RBC + Sand filt + Chlor.
MBR
(98.0%) (99.0%) (99.0%)
(96.1%) (100%)- (98.2%)
(98.8%) (100%)(99.5%) -
-
-
(90.0%) (90.0%)
Coagulation + Sand filtration + GAC
SBR (87.9%) -- -(11.4%)
-- -
Target: BOD > 90%; TN > 40%; Torbidity > 90%; Microbial parameters > 99.0%
Technologies3
Technologies for grey water treatment and reuse
• The combination of aerobic biological processes with physical filtration and/or disinfection is considered to be the most economical and feasible solution.
• Instead, biological treatment as the RBC (Rotating Biological Contactor) system will become economically feasible when the building size reach a certain dimension.
• The MBR (Membrane Bio Reactor) is the only technology being able to achieve satisfactory removal efficiencies of organic substances, surfactants and microbial contaminations without a post filtration and disinfection step.
Klosterenga, Oslo
Bologna
Berlin-kreuzberg
Preganziol, Treviso
Case studies
Case study (1)
Klosterenga, Oslo, Norway
Case study (1)
Klosterenga, Oslo, Norway
• Klosterenga, a 35-unit residential apartment building, an example of integrated design considering energy and water nexus.
• Each apartment has a dual waste-pipe system where toilet waste is pumped directly to the municipal sewage system.
• While grey water is pumped to the filtration system in the courtyard.
• In addition, rainwater is captured in rain barrels and used in the garden.
Additional funding for the realization of the project
Case study (1)
Klosterenga, Oslo, Norway
• During its operation, since 2000, the Klosterenga system has consistently produced an effluent with the following average parameters (Jenssen, 2004):
• COD = 19 mg/l; Total nitrogen = 2.5 mg/l; Total phosphorus = 0.03 mg/l; Faecal coliforms = 0.
• For nitrogen the effluent has consistently been below the WHO drinking water requirement (UNEP, 2006) of 10 mg/l and for bacteria no faecal coliforms have been detected.
Case study (2)
Preganziol, Treviso, Italy
Case study (2)
Preganziol, Treviso, Italy
• The system was designed for 240 populations equivalent (PE) in which grey water is treated with two constructed wetland systems (horizontal subsurface flow - HSF).
• The two reed bed are completely waterproofed, filled with fine gravel and planted with phragmites australis.
• Treated grey water, collected in a cistern, is subsequently used for toilet flushing by means of an indoor distribution system.
• Instead, rainwater is at first treated in a vertical flow constructed wetland system (with a surface of 50 m2) and then collected in storage tanks. Subsequently, rainwater and/or grey water are used for irrigation.
Case study (3)
Bologna, Italy
Case study (3)
Bologna, Italy
Distribution of consumptions
Water saving
Treatment scheme
Case study (4)
Berlin-Kreuzberg, Germany
Case study (4)
Berlin-Kreuzberg, Germany
• Apartment house for 70 persons;
• The grey water treatment scheme includes sedimentation, biological system with RBCs, final sedimentation and UV disinfection.
Where the reuse is essential...
MENA countries and Turkey
http://www.zer0-m.org/
Where the reuse is essential...
MENA countries and Turkey http://www.zer0-m.org/
Training and demonstration centre (TDS) general layout
in Turkey
SBRRBC
MBR
Conclusions
• All types of grey water have good biodegradability;
• The bathroom and the laundry grey water are deficient in both nitrogen and phosphors;
• The kitchen grey water has a balanced COD:N:P ratio.
With reference to the grey water characteristics, the following main conclusions can be withdrawn:
Considering technologies:
• Physical processes alone are not sufficient to guarantee an adequate reduction of the organics, nutrients and surfactants;
• Chemical processes can efficiently remove the suspended solids, organic materials and surfactants in the low strength grey water;
• The combination of aerobic process with physical filtration and disinfection is considered to be the most economical and feasible solution for grey water recycling;
• The MBR (Membrane Biological Reactors) appears to be a very attractive solution in collective urban residential buildings.
Conclusions
• The main advantage of the water recycling is in the saving of the water resource while, the main disadvantage is in the realization costs.
• However, an integrated design of the building (considering water and energy nexus) could make it more economically sustainable.
In addition:
References
• Amr M. Abdel-Kader (2013) Studying the efficiency of grey water treatment by using rotating biological contactors system. Journal of King Saud University – Engineering Sciences. 25, 89-95.
• Ernst, M., Sperlich, A., Zheng, X., Gan, Y., Hu, J., Zhao, X., Wang, J. and Jekel, M. (2008) An integrated wastewater treatment and reuse concept for the Olympic Park 2008, Beijing. Desalination 202(1-3), 221-234.
• Failla, B. and Stante, L. (2006). Efficient Management of Wastewater Treatment and Reuse in the Mediterranean Countries. Experimental Aquasave Project in households, Technologies and Results. In the proceedings of the Regional EMWater Project Conference, from 30 October to 1 November, Amman, Jordan.
• Friedler, E., Gilboa, Y. (2010) Performance of UV disinfection and the microbial quality of greywater effluent along a reuse system for toilet flushing. Sci. Total. Environ. 408, 2109-2117.
• Jefferson, B., Judd, S. and Diaper, C. (2001) Treatment methods for grey water. In “Decentralised Sanitation and Reuse, Concepts, systems and implementation”, edited by P. Lens, Zeeman G and Lettinga G., IWA Publishing, ISBN: 1900222477.
• Jenssen, P.D. (2004). Decentralized urban greywater treatment at Klosterenga Oslo. In: H.v. Bohemen (Ed.) Ecological engineering-Bridging between ecology and civil engineering, Æneas Technical Publishers, The Netherlands, pp 84-86.
• Li, F., Wichmann, K. and Otterpohl, R. (2009) Review of the technological approaches for grey water treatment and reuses. Sci. Total. Environ. 407(11), 3439-3449.
• Maeda, M., Nakada, K., Kawamoto, K. and Ikeda, M. (1996) Area-wide use of reclaimed water in Tokyo, Japan. Water Sci. Technol. 33(10-11), 51-57.
• Masi, F., El Hamouri, B., Abdel Shafi, H., Baban, A., Ghrabi, A. and Regelsberger, M. (2010) Treatment of segregated black/grey domestic wastewater using constructed wetlands in the Mediterranean basin: the zer0-m experience. Water Sci. Technol., 61(1), 97–105.
• Morel, A., Diener, S. (2006) Grey water management in low and middle-income countries. Water and Sanitation in Developing Countries (Sandec). EAWAG.
• Nolde, E. (2000) Greywater reuse systems for toilet flushing in multi-storey buildings – over ten years experience in Berlin. Urban Water 1, 275-284.
• Oron, G., Adel, M., Agmon, V., Friedler, E., Halperin, R., Leshem, E. and Weinberg, D. (2014). Greywater use in Israel and worldwide: Standards and prospects. Water Res., 58, 92-101.
• UNEP, 2006. WHO Guidelines for the safe use of wastewater, excreta and Greywater. In: Policy and Regulation Aspects, vol. 1. WHO, 20 Avenue Appie, 1211 Geneva 27, Switzerland p-100.
Italian National Agency for the New Technology, Energy and Sustainable Economic Development, Water Resource Management Lab.Via Martiri di Monte Sole 4, 40129, Bologna (ITALY)
Sabino DE GISI, PhD [email protected]
Patrizia CASELLA, PhD [email protected]
Roberto FARINA, MSc [email protected]
METROPOLITANA
MILANESE SPA