Managing Diffuse Sources: Alternative Concepts for Urban Water Infrastructure

Tove A. Larsen, Judit LienertEawag, Switzerland

© 2008 Tove A. Larsen and Judit Lienert

Wastewater Management is Multi-Tasking

Urban Hygiene

Water Pollution ControlStorm Water Management

Resource Recovery

Where do we find Wastewater Treatment Plants?

- 58 % of the world population is connected to a sewer system

- 24 % receive some level of sewage treatment

- 4 % primary- 15 % secondary- 5 % tertiary

Green et al. (2004) Biogeochemistry 68: 71-105

Secondary treatment

Tertiary treatment

Primary treatment

Wastewater Treatment Plants:The Eternal Story of the Next Problem

Reverse osmosisOzonation Activated carbon

And the new generation:

Ozonation of Treatment Plant Effluents:Simple and Cheap, but Energy-Intensive

• Proven removal ofabout 20 different compounds

• Not removed:iodinated X-ray contrast media

• Little information ontransformation products

• Energy demand: 0.1–0.3 kWh/m3

(comparable to the present demand)• Costs: 0.05–0.15 Є/m3

(present: 0.5-2.5 Є/m3)

Ternes et al. (2003) Water Research 37: 1976-1982Huber et al. (2004) Environmental Science & Technology 38: 5177-5186Joss et al. (2008) Water Science and Technology 57(2): 251-254

Activated Carbon in Treatment Plant Effluents:Simple and Cheap, but Energy-Intensive

• Broad removal of micropollutants• Total elimination of micropollutants

during carbon regeneration• CO2 emissions:

comparable to the present system• Costs: 0.08–0.20 Є/m3

(present: 0.5-2.5 Є/m3)

Nowotny et al. (2007) Environmental Science & Technology 41: 2050-2055Snyder et al. (2007) Desalination 202: 156-181Joss et al. (2008) Water Science and Technology 57(2): 251-254

Nutrients: A Global Threat2004: Worldwide 149 'Dead Zones'

UNEP is warning:'Dead zones may soon damage fish stocks more than unsustainable catches'

2006: Worldwide 200 'Dead Zones'11 of 50 new zones are published

UNEP demands:'Nitrogen emissions must be reduced'

+5

+2

The Nutrients are in Urine

Urine(1.5 liters/person/day)

Rest of wastewater(350 liters/person/day)

20 %

40 %

60 %

80 %

100 %

NitrogenPhosphorus

Potassium

Comparison of Different Technologies

low15–5070–8015NoMix technology (90 % separation efficiency)

see above>85see above

see above

WWTP + P-filter

low15–858590WWTP, sludge age >12 days + organic C-source

low15–8550–7590WWTP, sludge age >12 days

low15–852590WWTP, sludge age 8–10 days

high15–852575WWTP, sludge age 2 days

high80–9015–3060–75WWTP, chemical precipitation

high5–15530WWTP, primary treatment

PNCOD

NH4+

effluent concentrati

on

Typical removal efficiencies (%)

Larsen et al. (2007) Water Science and Technology 56(5): 229–237

Pharmaceuticals in Wastewater:Hoping for a Simple Solution

Urine(1.5 liters/person/day)

Rest of wastewater(350 liters/person/day)

20 %

40 %

60 %

80 %

100 %

Nitrogen

Phosphorus

Pharmac

eutic

als?

Larsen et al. (2001) Environmental Science & Technology 35: 192A-197A.

Pharmaceuticals in Wastewater:Not quite as Simple!

Urine(1.5 liters/person/day)

Rest of wastewater(350 liters/person/day)

20 %

40 %

60 %

80 %

100 %

Nitrogen

Phosphorus

Pharmac

eutic

als

Lienert et al. (2007) Water Science and Technology 56(5): 87-96.

Urine(1.5 liters/person/day)

Rest of wastewater(350 liters/person/day)

20 %

40 %

60 %

80 %

100 %

Nitrogen

Phosphorus

Potentia

l effe

cts

Pharmaceuticals in Wastewater:Not quite as Simple!Escher et al. (2006) Environmental Science & Technology 40: 7402-7408Lienert et al. (2007) Environmental Science & Technology 41: 4471-4478

Procedure for data collection

Literature survey(54 publications)

454 Pharmaceuticals

50 Pharmaceu-ticals with

qualitative data

Criteria(Only pharmaceuticals, excretion via

urine or feces, no ointments, eye,nose, or ear drops, …)

212 Pharmaceu-ticals with

quantitative data(=1‘409 products)

139 Pharmaceu-ticals without excretion data

401 Pharmaceu-ticals included

53 Pharmaceu-ticals excluded

Search forexcretion data

(in Swiss Drug Compendiumwww.kompendium.ch)

Lienert et al. (2007) Water Science and Technology 56(5): 87-96 (Figure 1)

Average excretion of 212 pharmaceuticals

On average …

… the larger fraction of each active ingredient is excreted via urine

… ca. 42% of each active ingredient is metabolized

… metabolites are mainly excreted via urine

But data inconsistency and extreme variability from 0 – 100%

0 20 40 60 80 100 120

64% total viaurine (± 27%)

35% total viafeces (± 26%)

35% unchangedurine (± 33%)

42% metabolizedurine (± 28%)

32% unchangedfeces (± 34%)

% % % % %% %

Lienert et al. (2007) Water Science and Technology 56(5): 87-96.

Excretion via urine of 22 therapeutic groups

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

GestagensCytostatics

AntihypertensivesNeuroleptics

AntilipidemicsAntibiotics

Glucocorticoids / CorticosteroidsDiuretic drugsBetablockers

AntiemeticsAntidepressants

VasodilatantsAntidiabetic agents

Arterial vasodilatorsAntiphlogisticsAntiviral drugs

EstrogensGastric acid inhibitors

Hypnotic drugsAntiepileptic drugs

AnalgesicsX-ray contrast media

> 80% excretion via urine

> 70% excretion via urine

> 60% excretion via urine

> 49% excretion via urine

min / max value

Lienert et al.(2007) Environmental Science & Technology 41: 4471-4478Lienert and Larsen (2007) Gaia 16(4): 280-288 (Figure 3)

Background-COD and Concentration:Important Parameters for Removal of Micropollutants

Combined wastewater (100 m3/p/year)

Typical European wastewater production

Urine (0.6 m3/p/year)Toilet (25 m3/p/year)

Wastewater influent (100%)

Wastewater effluent (10%)

Urine (5%)

Biologically treated urine (1%)

Background COD

Larsen et al. (2004) Journal of Biotechnology 113(1-3): 295-304

Alternatives to Wastewater Treatment PlantsHow can Feces be Treated?

Available for recycling Available for energy 0100 % 100 %

Burial (pit latrines)

Drying

Aerobic digestion (e.g. compost)

Anaerobic digestion

Microbial fuel cells

Total oxidation / burning

Larsen et al., in preparation for Journal of Environmental Management

Optimizing the whole system is difficult

WWTP

Sludge

Agriculture

Ground water

?

??

?

Urban area

Un-connectedareas

Rece

iving

wate

r

?

?

Combined Sewers Overflow

What can we Learn from the Past?Three Case-Studies

Non-degradable detergents:product design

Phosphate in detergents:replacement

Heavy metals:waste design

,Hard‘, non-degradable detergentshad to be replaced through degradable ones

Flow rateTotal phosphorusOrthophosphate

BUWAL 1994

Ban of phosphatein washing powder

River Rhine at Basel

Heavy Metals in Sewage Sludge from the City of Zürich

0

500

1000

1500

2000

1980 1982 1984 1986 1988 19900

5

10

15

20g Zinc / t Dry Matter g Cadmium / t Dry Matter

Zinc

Cadmium

Conclusions

- Better access to pharma-ceuticals than to treatment

- If only our part of the world counts: Wastewater treatment can do a lot

- With source separation, removal of pharmaceutic is more energy-efficient

- Solving the problems by product design is always better

For further information

www.novaquatis.eawag.chFinal report of the transdisciplinary Eawag project Novaquatis