Course 1 Unit 2

The characteristics of urine, faeces and greywater

Teacher Mariska Ronteltap

Course 1 Unit 2

Course 1 Unit 2

The characteristics of urine, faeces and greywater

Content

:     Brief introduction Part A: Characteristics of urine Part B: Characteristics of faeces Part C: Characteristics of greywater 2

Brief introduction

CHARACTERISTICS

3

Separated „waste“ streams are easier to treat and reuse

Substance urine (yellow water) faeces (brown water) greywater (shower, washing, etc.) rainwater organic waste Treatment examples storage anaerobic digestion, drying, composting constructed wetlands, soil filters, membrane technology filtration, biological treatment composting, anaerobic digestion Reuse N-rich fertiliser biogas, soil improvement

= black water (with small amount of flush water)

irrigation, groundwater recharge, toilet flushing water supply, groundwater recharge soil improvement, biogas

Source: GTZ-ecosan project, resource book

4

“Waste” streams discussed in this lecture

1. Urine 2. Faeces 3. Greywater 4.

5.

Anal washwater Conventional domestic wastewater – for comparison purposes 5

Course 1 Unit 2

Nutrients: important component of waste streams!

 Macronutrients*: – Nitrogen (N) – Phosphorus (P) – Potassium (K) – Sulphur – Calcium – Magnesium A fertiliser which contains these three nutrients is called a “complete” fertiliser  Micronutrients: – Boron, copper, iron, chloride, manganese, molybdenum and zinc TN = total nitrogen, e.g. urea-N plus ammonia-N (for urine) TP = Total phosphorus 6 * The definition of macronutrients and micronutrients for human nutrition is different, see e.g. http://www.fivims.net/glossary.jspx?show_result=true?lang=en#M (or the course glossary)

Role of measurement parameters for urine, faeces and greywater

Parameter Purpose of measuring

Dry mass, moisture content (for faeces) Total nitrogen (TN), total phosphorus (TP), potassium (K), ammonia-N COD, BOD (chemical / biological oxygen demand) and VS (volatile solids) pH Solids content, mass to be transported Nutrient content for fertiliser value (or for pollution potential if discharged to water course) These parameters determine the organic matter content: most soils will benefit from addition of organic matter (soil conditioner); but organic matter can also be a cause of odour in greywater pH around neutral is best for reuse TDS (total dissolved solids) Electrical conductivity The lower the TDS the better for reuse of water (high TDS means “very salty”) Proportional to TDS and correlated with ammonia-N Indicator for pathogens (e.g. helminth eggs,

E. coli

) Assess public health risk (some of these tests may be expensive) 7

C1U2 - Part A

CHARACTERISTICS OF URINE

8

Human urine quantity facts

Human physiology facts: – The body uses urine as a balancing medium for liquids and salts – The kidneys filter urine from the blood – At excretion, the urine pH is normally around 6 but can vary between 4.5 – 8.2

Adults excrete about 0.8 – 1.5 L of urine per day (children about half that amount) depending on time, person and circumstances: – Excessive sweating results in concentrated urine – Comsumption of large amounts of liquid dilutes the urine 9

Nutrients in human urine

 

Digested nutrients enter the metabolism and are excreted mostly with the urine and the rest in faeces Urine contains 88% of excreted N, 67% of excreted P and 73% of excreted K; the remainder is in the faeces – This ratio of nutrient split between urine and faeces appears to be more or less the same worldwide

10

Urea facts

    Of the nitrogen in fresh urine, 75-90% is in the form of urea; the remainder is in the form of ammonium or creatinine Urea is (NH 2 ) 2 CO – an organic nitrogen compound (contributing to COD a content of urine) Urea is easily converted to ammonium by urease (an enzyme excreted by bacteria, that is present everywhere) – In conventional mixed wastewater, about 78% of the total nitrogen is therefore in the form of ammonia already Urea can be made artificially from ammonia and CO 2 and is a popular fertiliser world-wide – Urea has the highest proportion of N of all liquid fertilisers: 46.4% N in urea a COD = Chemical Oxygen Demand (see also Table 1 later in this presentation) 11

Urine storage

Course 1 Unit 2

Fresh (24 March 06) One month old (24 April 06) Fresh (24 March 06) One month old (24 April 06) Three months old (28 June 06) Note the change in colour, increasing cloudiness, sediments (precipitates) 12

Main processes during urine storage

The nitrogen in fresh urine is mostly in the form of urea (75 90%), with very little ammonia Ammonia (gas) Upon storage, the urea is quickly degraded to ammonia (NH 3 ) by the enzyme urease, and hence the ammonia concentration increases Higher ammonia concentrations result in a pH increase to 9 - 9.3

The increased pH value causes a precipitation of certain crystals and precipitates (precipitation of P, Mg, Ca and NH 4 occurs) Sludge/ precipitates 13

   

Other comments on processes during urine storage

Ammonia (gas) There is a risk of losing N in the form of ammonia with the ventilated air The colour of the urine changes from bright yellow to orange/red Sludge forms where urine usually stands for a while – This sludge largely consists of struvite and apatite – It is formed because the pH of the urine increases to 9-9.3 and at this high pH, precipitation of P, Mg, Ca and NH 4 occurs Urine is very corrosive (use plastic or high quality concrete for storage, not metals) – see also Course 2 Unit 3 (Storage and transport logistics) Sludge/ precipitates 14

Pathogens in urine

    Pathogen types: bacteria, viruses, parasitic protozoa and helminths Number of pathogens in urine is very low One pathogen of concern is Schistosoma haematobium (causing bilharziasis), where eggs can be excreted in the urine 

In areas where this pathogen is endemic, urine should not be used on fields near freshwater sources

Hygiene risks associated with diverted urine are mainly a result of contamination by faeces  Urine use in agriculture is “pretty safe” – see more details in Course 2 Unit 1 Part A (Treatment aspects for urine, faeces and greywater) 15

Chemical contaminants in urine

  Heavy metals (Cu, Zn, Cr, Ni, Pb, Cd):  Levels of heavy metals in urine are very low because only substances that have entered the metabolism are contained in urine Hormones (endocrine disrupters) and pharmaceuticals:  A large proportion of the hormones produced by our bodies and the pharmaceuticals that we consume are excreted with the urine  As a rule of thumb, an average of 64% of a substance ingested is excreted in the urine (Escher

et al.

, 2007)  It is considered better to recycle urine to arable land than to flush the hormones and pharmaceuticals into recipient waters because: • Hormones and pharmaceuticals are degraded in natural environments with a diverse microbial activity • Urine is mixed into the active topsoil and retained for months (see Course 3 “Reuse of ecosan products in agriculture”) 16

Pharmaceutical residues in urine (continued from previous slide)

The load of pharmaceutical residues from animal manure which is freely spread on land has never concerned anyone Some research is ongoing in Europe on this aspect (e.g. ozonation of urine to degrade pharmaceutical residues), but it is not a very important research question for the field of low-cost sanitation (see also Course 2 Unit 1 “Treatment aspects of urine, faeces and greywater”) What is your opinion on this? You can answer on the forum!

17

Course 1 Unit 2

Nutrient excretion by humans is directly linked to diet N Excreta Diet

P

N

P    Diet is the main factor for amount of nutrients excreted Relationship to calculate the amount of nutrients excreted (in total) from the food intake:  

N = 0.13 x total food protein P = 0.011 x (total food protein + vegetal food protein)

FAO statistics are available for food supply for different countries (see www.fao.org) 18

Estimated excretion of nutrients per capita in different countries based on diet (using data and correlation mentioned on previous slide)

Source: J önsson

et al.

(2004), page 6 19

Table 1: Excreted mass of nutrients in urine per year (typical values for Sweden)

Wet mass kg/cap/yr 550 Volume Dry mass Total nitrogen (TN) L/cap/yr kg/cap/yr kg/cap/yr 550 21 4 Values are country-specific or diet-specific (treat as guideline only!) Total phosphorus (TP) Potassium (K) COD BOD kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr 0.37

1 3.6

1.8

cap = capita = person Useful for calculating crop demand or area required for application.

Source: J önsson

et al.

(2004), and Otterpohl (2003) for COD data; BOD assumed to be half of COD COD and BOD are measures of organic content; see lecture on “Fundamentals of conventional biological wastewater treatment” 20

Table 2: Urine data - same data as in Table 1 but per day

Wet mass Volume Dry mass Total nitrogen (TN) Total phosphorus (TP) Potassium (K) COD g/cap/d L/cap/d g/cap/d g/cap/d g/cap/d g/cap/d g/cap/d 1507 1.5

57.5

11.0

1.0

2.7

9.9

21

Table 3: Urine data - same data as in Table 1 but given as concentrations

Dry mass Total nitrogen (TN) Total phosphorus (TP) Potassium (K) COD BOD pH Own determinations: COD VS (volatile solids) content Electrical conductivity (EC) TDS (total dissolved solids) mg/L mg/L mg/L mg/L mg/L mg/L mg/L % m S/cm mg/L 38200 7300 670 1800 6500 3250 6 (4.5 – 8.2) 5,200 – 10,300 16-32 10,600 – 25,100 7,800 – 18,000 Concentrations are useful when working with urine of unknown number of people Results from lab session on 20 Sept 06 with 18 MSc students Urine is highly saline (see next slide) 22

Some additional information on TDS and EC

   For conventional wastewater, the following relationship holds (Metcalf and Eddy, page 56)  TDS (mg/L) ~= EC (mS/cm) x (0.55 – 0.70) or  EC (mS/cm) ~= 1.6 x TDS (mg/L) Pure urine is not to be used as irrigation water, but as a fertiliser Nevertheless, the classification of water in regards to saltiness is shown below for comparison purposes: Name of water Non-saline Slightly saline Moderately saline Highly saline Very highly saline Seawater TDS (mg/L) < 500 > 500 – 1,500 > 1,500 – 7,000 > 7,000 – 15,000 > 15,000 – 35,000 > 35,000 Urine 23

Differences between fresh and stored urine (data set 1)

Source: Novaquatis research project, published in Eawag News (March 2007) http://www.eawag.ch/services/publikationen/eanews/news_63/en63e_maurer.pdf

The main difference is the much higher ammonium + ammonia concentration in stored urine The table does not include data for ortho-P, but it would be lower in the stored urine than in the fresh urine (soluble P is precipitating to form various crystals) 24

Differences between fresh and stored urine (data set 2)

Parameter pH TN NH 4 -N (includes NH 3 -N) TP COD Conductivity TDS Ratio conductivity/TDS Unit mg/L mg/L mg/L mg/L mS/cm mg/L mS/cm / (mg/L) Old Urine 9.8

5730 5780 940 6900 23000 Fresh Urine 8.2

6060 630 400 7300 19200 14800 1.30

Source: Determinations at UNESCO-IHE laboratory with class during Ecosan Summer School in Sept. 2006. Values are averages of 6 groups (old urine sample was 7 months old; fresh urine samples were different for each group (taken on same day)).

How about letting your own students do some determinations? It is a good experience…

25

C1U2 - Part B

CHARACTERISTICS OF FAECES

26

Course 1 Unit 2

Faeces quantity and content

      Faeces consist mainly of non-metabolised material combined with some metabolised material Undigested nutrients are excreted with the faeces The lower the digestibility of the diet, the higher the mass of faeces excreted per day, e.g.:    Average person in Sweden: 51 kg/cap/yr (wet mass) Average person in China: 115 kg/cap/yr Average person in Kenya: 190 kg/cap/yr Extremely high number of many different pathogens Heavy metal content in faeces is higher than in urine (heavy metals pass through the intestine unaffected) Concentrations of contaminating substances in faeces are usually lower than in chemical ferilisers (e.g. cadmium) and farmyard manure 27

What does it look like when faeces dry out?

This is one of the daughters of Elisabeth Children have no problem with faeces… This is actually a bucket latrine for children

28

Air drying of faeces

Fresh faeces (14 May 06) 2 days old (16 May 06) 2 weeks old (1 June 06) 6 weeks old (28 June 06) 29

Trial # 1 Faeces of a 2.5 year old girl

After two weeks of drying: appears totally dry, Dead flies: container was covered but holes in lid, flies could not get out (??)

Data of own faeces drying trials

Start End

Trial # 1 (drying time 14 days) Weight (g) Water lost (g)

Moisture (calculated) (%)

Dimensions (cm) Volume (mL) Density (kg/L) 60

75

4 x 6 x 2.5

60 1.17

15 45 g 3 x 4.5 x 2 27 0.55

Trial # 2 (drying time 12 days) Weight

Moisture (calculated) (%)

70

71

20 31

Course 1 Unit 2

Table 4: Excreted mass of nutrients in faeces per year (typical values for Sweden)

Wet mass Volume (at excretion i.e. before drying) Dry mass Total nitrogen Total phosphorus Potassium COD BOD kg/cap/yr L/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr 51 51 11 0.55

0.18

0.4

14 7 Values are country specific or diet-specific (treat as guideline only!) Useful for calculating crop demand or area required for application Source: J önsson

et al.

(2004), and Otterpohl (2003) for COD BOD assumed to be half of COD 32

Table 5: Faeces data - same data as in Table 4 but per day

Wet mass g/cap/d 140 this is the mass of wet faecal matter excreted per person per day Volume (at excretion) L/cap/d 0.1

this is the mass of faeces after drying, per person per day Dry mass g/cap/d 30 Total nitrogen g/cap/d 1.5

For comparison: solid waste production is 200 – 500 g/cap/d in cities in India Total phosphorus g/cap/d 0.5

(Source: Rothenberger

et al.

, 2006, page 93) Potassium g/cap/d 1.1

COD g/cap/d 39 33

Table 6: Faeces data - same data as in Table 4 but given as concentrations in g/kg wet mass

Dry mass (at excretion) Total nitrogen (TN) g/kg g/kg 216 11 Total phosphorus (TP) Potassium g/kg g/kg 4 8 Useful when working with faeces of unknown number of people Moisture content Dry matter content (at excretion) pH % % 78 22 7 – 9 (?) How to measure the organic content (COD and BOD were developed for liquids)?

 Volatile solids content or ignition loss; TOC How to measure pH?

 Dilution with water + shaking, or pH meter for soil 34

Main differences between fresh and old (dried) faeces (collected without flush water)

  The old, dried faeces has:  Less moisture, volume, weight, density  Much fewer pathogens (note: of all the pathogens, the helminth eggs are most resilient) No attractiveness for flies anymore A much less offensive appearance to the human eye Note: These points do not apply for old faeces which is stored together with water and urine!

35

C1U2 - Part C

CHARACTERISTICS OF GREYWATER

36

Greywater - definition

   Greywater is domestic wastewater with no or minimal human excrements Sources are kitchens, baths, showers, laundry, washing Some faecal matter enters if nappies are washed in the laundry for example (households with pit latrines automatically have a “source separation” of greywater) 37

Greywater quantities generated

     Range: 60 – 275 L/cap/d (depending on country and wealth/attitude of user) Some new houses in Germany, Norway, Sweden: less than 100 L/cap/d Rural Jordan example: 20 L/cap/d (water is precious, so is used several times) Note: Basic lifeline water requirement: 25 or 50 L/cap/d (Gleick, 1998) For comparison: Drinking water requirement: 3-5 L/cap/d 38

Greywater characteristics: organic matter, nutrients, pollutants

   Organic matter (BOD): High concentrations of easily degradable organic material, e.g. fat, oil and other organic substances from cooking, residues from soap, shampoos and tensides from detergents Nutrients: – Nitrogen levels low – Phosphorus input from washing and dish-washing powder (for water softening) – some countries, e.g. Norway, have banned washing powder containing P Metals and other toxic pollutants: Metals originating from water itself, corrosion of pipe system, dust, cutlery, dyes, shampoos (similar to conventional wastewater) Source: Ridderstolpe (2004) 39

Greywater characteristics: pathogens

 Proportion of pathogens is low (some faecal contamination possible) – Greywater has lower pathogen content than treated effluent from most conventional wastewater treatment plants (unless they include tertiary treatment for disinfection)  Amount of faeces in greywater: – Based on measured faecal sterols, the estimate is that about 0.04 g/cap/d of faeces is mixed into the greywater (compared to 30 g/cap/d of faeces produced, i.e. 0.1%) – Note: use of indicator bacteria to measure the amount of faeces in greywater might be misleading because of their growth on organic matter that is contained in greywater Source: Ridderstolpe (2004) 40

Course 1 Unit 2

Table 7: Greywater characteristics

Volume Total suspended solids (TSS) Total nitrogen (TN) Total phosphorus (TP) Potassium COD BOD pH L/cap/d mg/L mg/L mg/L mg/L mg/L mg/L 60 275 365 6 3 15 562 281 7-8 Only to provide an idea – highly variable and dependent on water use patterns Concentrations are based on Otterpohl (2003) mass flows, and flowrate of 60 L/cap/d 41

Anal cleansing materials used world-wide

     Toilet paper: collect in faeces compartment of UDD toilet if material to be composted or incinerated, otherwise store separately Water (see next slide) Vegetable materials: collect in faeces compartment Stones or rags: collect separately Newspaper, card board: treat same as toilet paper Note: absence of available anal cleansing material next to the toilet can lead to higher incidence of diarrhoea (Herbst (2006) proved this correlation for a case study area in Uzbekistan) 42

Anal washwater

     Origin: Practise of many cultures (e.g. Muslims and Buddhists) to wash anal area after defecating and after urinating* = Water with a low level of faecal matter Treatment methods for anal washwater similar to those for greywater, e.g. constructed wetlands, soil infiltration Poorly characterised (few studies) Should not be mixed with urine; can be mixed with greywater * Therefore, there are no public free-standing urinals for men in muslim countries – only in cubicles 43

Table 8: Summary table of mass of nutrients in urine, faeces and greywater Parameter Unit kg/cap/yr Urine 550 Faeces 51 Total 601 % in urin e 92% Wet mass Volume (before drying) Dry mass L/cap/yr kg/cap/yr 550 21 51 11 601 32 92% 66% Grey wat er

21900 21900 8

Total nitrogen Total phosphorus Potassium COD BOD kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr 4 0.37

1 3.6

1.8

0.55

0.18

0.4

14 7 4.55

0.55

1.4

17.7

8.85

88% 67% 71% 20% 20%

0.14

0.08

0.32

12 6.2

For greywater used 60 L/cap/d (quite low consumption) Source: J önsson

et al.

(2004), and Otterpohl (2003) for greywater data and COD. BOD assumed to be half of COD 44

Course 1 Unit 2

Volume of greywater, urine and faeces

Greywater urine faeces

Can be a good source of irrigation water if managed safely 500 L/cap/yr 50 L/cap/yr Mind that there is a large variation in volume (related to country and standard of living) – 66 to 274 L/cap/d Source: Otterpohl (2003) 45

Mass of nutrients

0 6 greywater This is a „complete“ fertiliser (= containing N, P, K) urine faeces

K P N

Source: Otterpohl (2003) 46

Mass of organic matter (measured as COD)

20 greywater urine faeces Highly beneficial when applied to soil as soil conditioner (see Course 3 Unit 1 „Reuse of ecosan products in agriculture) 0 Source: Otterpohl (2003) 47

For comparison: conventional domestic wastewater

     Conventional domestic wastewater is wastewater from households connected to a sewer system, without any separation of waste streams Polluted water with high levels of pathogens Large volumes that need treatment Industrial effluent (untreated or pre-treated) is mostly mixed together with domestic wastewater Rainwater and sewage are mixed intentionally (combined sewer) or mixed partially (separate sewer) – it is difficult to keep rainwater completely out of sewers, unless they are brand new 48

Course 1 Unit 2

Table 9: Overview of characteristics of “waste” streams

Parameter (concentrations) TSS Nitrogen Phosphorus Organic matter (COD, BOD) Pathogens Heavy metals Urine L

H

H L L L Faeces N/A M M H

H

L Grey-water M L

M M

L M Convent. domestic ww M M M H H M Organic solid waste N/A M L H L L L Low M Medium H High N/A Not applicable Toxic substances: heavy metals, pesticides, chlorinated organic compounds etc.

49

Table 10: Comparison with conventional domestic wastewater

Parameter Urine Faeces Greywater Volume, L/cap/year Nitrogen, kgN/cap/year Phosphorus, kgP/cap/year Organic matter, kgCOD/cap/year 550 4.0

0.37

3.6

51 0.55

0.18

14 24,000 – 100,000 0.14

0.08

12 Convent. domestic ww a 95,000 5.8

0.5

55 a For US conditions: 260 L/cap/d, 16 gN/cap/d, 1.5 g P/cap/d, 68 gBOD/cap/d, 150 gCOD/cap/d cap = capita = person Source: Otterpohl (2003) (for faeces, urine and greywater data) 50

“Water footprint” of an individual or a nation

   So far, we have only looked at the greywater production resulting from domestic activities If you want to investigate your total water consumption, you also need to consider water used to produce the food that you eat and the industrial products you consume  Vegetarians have a much lower water consumption for their food production than meat eaters  Poor people also have a much lower water footprint than wealthy people (typically) A water footprint calculator is available here: http://www.waterfootprint.org/index.php?page=files/home 51

Average national water footprint per capita (m3/cap/yr)

Green means that the nation's water footprint is equal to or smaller than the global average. Countries with red have a water footprint beyond the global average. Period: 1997-2001. 52 Source: http://www.waterfootprint.org/index.php?page=files/WaterFootprints

References

        Escher, B. (2007) Can NoMix help to prevent environmental problems caused by medicines? Eawag News: Mix or NoMix? A closer look at urine source separation, 63(March), 23-25. http://www.eawag.ch/services/publikationen/eanews/news_63/en63e_escher.pdf

Gleick, P. H. (1998) The human right to water, Water Policy 1, p. 487-503 * Herbst, S. (2006) Water, sanitation, hygiene and diarrheal diseases in the Aral Sea area (Khorezm, Uzbekistan). PhD thesis, University of Bonn, Germany * J önsson, H, Richert Stinzing, A., Vinneras, B., Salomon, E. (2004) Guidelines on the Use of Urine and Faeces in Crop Production, Stockholm Environment Institute (get from www.ecosanres.org

) * Otterpohl, R. (2003) New technological development in ecological sanitation. Proceedings of 2nd international symposium on ecological sanitation, April 2003, Lübeck, Germany, p. 455 ( http://www.gtz.de/de/dokumente/en-ecosan-symposium-luebeck-session-e-2004.pdf

) * Ridderstolpe, P. (2004) Introduction to greywater management, Stockholm Environment Institute, Sweden (get from www.ecosanres.org

) * Rothenberger, S., Zurbrügg, C., Enayetullah, I., and Maqsood Sinha, A. H. M. (2006) Decentralised composting for cities of low- and middle-income countries - A users' manual, Eawag/Sandec (Switzerland) and Waste Concern (Bangladesh), Dübendorf, Switzerland. http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_swm/downloads _swm/decomp_Handbook_loRes.pdf

Tchobanoglous, G., Burton, F.L., Stensel, H.D. (2003) Wastewater Engineering, Treatment and Reuse, Metcalf & Eddy, Inc., McGraw-Hill, 4th edition. Good book on conventional wastewater treatment * This publication is available on the I-LE for this unit (either assigned reading or extra materials) 53