Green Dorm Wastewater System

Green Dorm Wastewater SystemJBM Associates

BinBin JiangMegan BelaMichael Murray

June 7, 2005

Living Laboratory

Sustainable Living

Pioneer Model for Future Change

Sustainable Buildings at Stanford Today

Leslie Shao-ming Sun Field Station:

Rainwater catchment, waterless urinals

Vaden Health Center:

No water savings

Escondido Village 5 & 6:•Low flow appliances

•Efficient irrigation

•Native plants

•Minimize runoff

Water Goals:

• 50% reduction of potable water use

• 100% reduction of lake water use

• 50% reduction of wastewater discharge

Project Structure:

Water Balance

Initial Assumptions

Nutrient Balance

Greywater System

Blackwater System

Classification

Source Reuse

Greywater (Laundry)ShowerBathroom Faucet

(Laundry)IrrigationToilet Flushing

Blackwater ToiletKitchen Faucets

Experimental UsesCompost fromKitchen scraps

Working Definitions

Water BalanceInitial Assumptions Nutrient Balance Greywater SystemBlackwater System

Anaerobic MBR

Urine Treatment

Ex. watersupply

Fertilizer Production

Compost

Lab

Sewer

House

Layout


EquarisZeeWeed

MBR

Water Conserving Strategy

Water conserving washing machines LG WM2677H 40.9→12gal = 71%

Low flush toilets Caroma Smartflush 1.5→0.95gpf = 37%

Low flow showerheads Niagara Prismeare 2.11.5gpm = 28.5%


Water Balance

Purpose:Viability of water reuse scheme

Source of data: AWWA water use survey/Stanford data

Method

Category

L/capita-d

% of total

Dishwashers 3.8 2%

Other Domestic 6.1 4%

Leaks 36.0 23%

Faucet – Kitchen 25.4 16%

Faucet - Bathroom 15.9 10%

Shower 34.8 22%

Clothes Washers 17.0 11%

Toilets 16.7 11%

Total 155.6 100%

Previous 221.1


Water Balance- Assumptions

Regulatory ambiguity concerning clothes washing water

Scenario 1 – All clothes washing water recycled Scenario 2 – Clothes washing water sent to

sewage

Recycled Water

Clothes Washers Toilets Irrigation

Sewage

1

2


Water Balance - Results

(liters/day/person)

Scenario 1 (washer recycling)

Scenario 2 (no washer recycling)

Total Potable water used 122 122

Total potable water recycled 51 51

Recycled water needed 17 34

Total black water created 46 63

Irrigation water created 34 17

Potable Water Savings 45% 45%

Black Water Savings 74% 65%Water BalanceInitial Assumptions Nutrient Balance Greywater SystemBlackwater System

Nutrient Balance

Purpose Identify major nutrient sources Optimize treatment for reduction in nutrient

loading

Methodology Scale per-capita production of BOD, COD, N,

and P (from literature)

Water BalanceInitial Assumptions Nutrient BalanceGreywater SystemBlackwater System

Nutrient Balance - Results


Source BOD (kg/yr) COD (kg/yr) N (kg/yr) P (kg/yr)Grey water

Shower/Sink 100 200 20 10Laundry --- 500 0 10

Black waterToilets (Solids) 500 1510 20 10

Urine 0 0 200 30Kitchen, liquid 600 900 20 0Kitchen, solid 600 1810 10 40

Total 1800 4920 270 100

Nutrient Balance - Conclusions

Compost pile for kitchen scraps removes 35% of P

Divert up to 60% of N, 25% of P by separating urine

Liquid kitchen waste comparable to solid toilet waste as nutrient source


Water Quality of Wastewater Stream

Purpose Identify experimental uses Optimize grey and black water

treatment

Methodology Combine water and nutrient balances


Water Quality of Wastewater Stream - Results


Source Flow Rate (m3/yr) [BOD] [COD] [N] [P]Grey water 1320 --- 525 15 15

Shower/Sink 990 100 200 20 10Laundry 330 --- 1500 0 30

Black water 1230 900 1980 200 30Toilets (combined) 330 1540 4640 680 120

Solids 290 1730 5240 70 30Urine 40 0 0 5430 810

Kitchen, liquid 570 1060 1590 40 0

Water Quality of Wastewater Stream - Conclusions

Separated urine is highly concentrated source of N and P -> fertilizer

BOD levels comparable in liquid kitchen and solid toilet waste -> combine treatment

Concentrated laundry water diluted by showers


Anaerobic MBR

Urine Treatment

Ex. watersupply

Compost

Lab

Overview of Greywater

System

Anaerobic MBR

ZeeWeedMBR

Ex. watersupply


Compost

Lab

Sewer


Equaris

Greywater Treatment: Equaris System


Standard wastewater treatment with extended aeration

Surge Tank

Aeration Tank

Clarifying Tank

www.equaris.com

Greywater Treatment: Equaris System


• 950 lpd capacity per system• 68 lpd per capita • 55 people

4 systems needed (3740 lpd total)

NRDC- Santa Monica

www.equaris.com

www.equaris.com

Greywater Treatment: ZeeWeed Membrane Bioreactor


Aerobic Membrane Bioreactor by Zenon

www.zenonenv.ocm


Greywater Treatment: Zeeweed Membrane Bioreactor

•1470 lpd to 75,800 lpd• Able to treat greywater and blackwater

www.zenonenv.ocm

City of San Diego

Comparison of two systems

Similarities DifferencesModularity Cost

Compliance with Regulations

Water Quality

Monitoring Available/LowMaintenance

Footprint

Equaris Zenon MBR

$32,158 including installation

~ $500,000

Equaris Zenon MBR

50-88% reductionin TSS

2.5 log removal TSS (<1 mg/L)

83-90% reduction in Nitrogen

< 1 mg/L N

78-93% reduction in BOD

< 5 mg/L BOD

3 log removal of bacteria

4 log removal of bacteria


Equaris Zenon MBR

816 ft3

(23 m3)330 ft3

(9.3 m3)

Cost

Water Quality

Footprint

Recommendation:

Phase I: Installation of Equaris

Phase II: Installation of ZeeWeed MBR

In the future: Both systems can be expanded to include other row houses. Drinking water purification in the future possible


Greywater Irrigation: Clivus Multrum

Available grey water: 51 liters/day

GW used by toilet flushing: 16.7 l/d

GW used by washing machines : 17.3 l/d

Amount of grey water left for irrigation:


17 l/d or 34 l/d

More cost-effective alternative:

Water storage until summer and pump for irrigation


Data logging and sampling

Monitor water quantity from each facility (GW and blackwater): flow, velocity

Monitor water quality: turbidity, pH, water level, TDS, etc

Water samples to lab for detecting pathogens


Watersensors.com: YSI ADV6600 Water Quality and Quantity Sonde

Overview of Blackwater System


Anaerobic MBR

Urine-Separating

Toilets


Sewer

Storage,Treatment

Liquid KitchenWaste

Urine Separation

Divert N and P from wastewater stream

N:P ratio of 6.7 optimal for agriculture

Utilized in ancient China and modern Europe

Green Dorm could fertilize 4.5 acres of tomatoes or 3.5 acres of corn annually


Urine Separation: System

Ekologen

Urine Stream(Non-Metal

Piping)

Fiberglass Storage Tank

15 m3Empty 2x per year

OnsiteTreatment Tank

6 months at 20°C

Diluted or As-IsFertilizer

Application

Urine-separating toilet diverts1.25 l/pd urine plus 0.75 l/pd flush


The Future: Anaerobic MBR


Experimental MBR at University of Bath, UK

Solid Toilet Waste

Anaerobic MBR

Potable Water

Electricty from Methane

Sludge Composter

(CO2)

Anticipated Performance

Anaerobic MBR

Urine Treatment

Ex. watersupply

Compost

LabAnaerobic

MBRZeeWeed

MBR

Ex. watersupply


Compost

Lab

Sewer

Equaris

Potable water savings: Potable water savings: 45%45%

Wastewater discharge Wastewater discharge

reduction: reduction: 65–74%65–74%

Reduction of N in wastewater Reduction of N in wastewater

effluent: effluent: 12-55%12-55%

Pioneering new technology and Pioneering new technology and processesprocesses

Acknowledgements from JBM

Documents

Green Dorm Wastewater System