and management Dr Kirsty Carden, University of Cape Town 18 April - - PowerPoint PPT Presentation

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Resource guidelines for greywater use and management Dr Kirsty Carden, University of Cape Town 18 April 2016 Water Research Commission project K5/2592 Development of resource guidelines for greywater use and management 1 Agenda for workshop

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Resource guidelines for greywater use and management

Dr Kirsty Carden, University of Cape Town 18 April 2016 Water Research Commission project K5/2592 Development of resource guidelines for greywater use and management

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1

Agenda for workshop

  • 1. Welcome
  • 2. Background to project – status quo
  • 3. Introduction to greywater harvesting assessment tool
  • 4. Identification of thematic areas / issues to be addressed
  • 5. Way forward
  • 6. Closure
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2

Strategic planning

“South Africa is a ‘water-stressed’ country, bordering on water scarce…water may become a binding constraint on development, at least in some parts of the country. There is a need for urgent attention to be given to the management and conservation of water resources, especially in stressed water catchments… Addressing supply and demand in the context of unevenly distributed and variable resources is a matter of central importance in national planning.” (National Planning Commission, 2011) ‘In many parts of the country, we are fast approaching the point at which all of

  • ur easily accessible freshwater resources are fully utilised. All South Africans

must recognise this situation so that necessary steps are taken to assess current and future demands for water. This will not be an easy task, but with the necessary resolve to plan and implement the required interventions, a secure water future can be achieved.’ – NWRS2, 2013, page 4

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Water security issues

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Predicted total water withdrawals

(Source: Hedden, 2016)

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Resilience-based water management

Blue water Sector approach dominated by economics and engineering, emphasis on supply Integrated blue water An economic approach to freshwater including environmental flows Integrated blue and green water Adding land interactions, surface runoff and infiltration to food, energy, and ecosystem services Green and blue water with social and ecological interactions Resilience based, addressing the need to sustain rainfall, capture resource value, and cross scale interactions and feedbacks

IWRM / IUWM SuDS WSUD

Evolution from the 1990s to present day realisation

Adapted from Rockstrom et al., 2014

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Diversifying household water sources

Precipitation Evapo-transpiration Reduced volumes of runoff Increased Infiltration Reduced wastewater discharge Reduced Municipal potable water demand Stormwater Harvesting Rainwater Harvesting Groundwater Greywater reuse

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Greywater recycling

Source: Ana Delétic

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Household greywater system

Image from http://www.waterrhapsody.co.za

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Simple home-based greywater systems

Photos courtesy of Kevin Winter

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Combined rain- and greywater harvesting

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Greywater irrigation in rural areas

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Greywater tower gardens

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Draft National Sanitation Policy (2016)

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Quality issues

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Greywater management in informal settlements

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Greywater management in informal settlements

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Project aims

Address (and mitigate) the risks associated with the management and use of domestic greywater, and support the wider uptake of this practice in South Africa, in order to realise diverse benefits such as:

  • building resilience into the water supply system;
  • managing water demand;
  • reducing volumes of greywater to wastewater

systems;

  • reducing diffuse pollution loads from un-serviced

settlements

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Technical background report

  • Definition of terms and concepts
  • Role of greywater management in water supply and

food security

  • Applicable regulations / policy / guidelines on

greywater use and management

  • Existing greywater use and management systems
  • Recommendations for sustainable greywater use

and management

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Greywater guidelines

  • Greywater quantity / quality and fitness for use /

application

  • Managing risks and uncertainty in greywater use /

reuse

  • Use of greywater to supplement irrigation activities
  • Greywater management options, including:

treatment, disposal and reuse

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Method

  • Compile relevant research findings
  • Survey greywater system users at household scale
  • Local and national stakeholder workshops
  • Review of legislative and health aspects
  • Focus group discussions
  • Develop guideline document, including a simple

‘operations and maintenance’ manual, as well as the strategic technical background document

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Quantifying risk in a guideline

Lloyd Fisher-Jeffes Greywater harvesting Workshop 1 18 April 2016

www.wsud.co.za

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Overview

  • We know greywater can be dangerous
  • Micobiologically
  • Chemically
  • SA Water Quality Guidelines
  • Old
  • Generalised
  • Relevance?
  • New approaches to risk management
  • DALY
  • Is it easily understood?
  • What parameters should we focus on
  • Environmental
  • Legal implications
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Varying Quality of greywater

Reference Eriksson et al., 2003 Rose et al., 1991 Cassanova et al., 2001 Source Composite Shower Laundry wash Laundry rinse Composite Composite Concentration (mg/ℓ unless

  • therwise stated)

Range Range Range Faecal coliforms (CFU/100ml) 6.0×103 126 25 1.82×104- 7.98×108 5.63×105 Faecal Streptococci (Enterococci) (CFU/100ml) 2.38×102

  • E. coli

(CFU/100ml) <100-2800 For formal fully serviced residential houses – greywater in informal settlements will have very different characteristics

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SAWQG – Whats an appropriate standard?

According to the South African Water Quality Guidelines (DWAF, 1996), gastro-intestinal and other illnesses can be expected to rise when people are in contact with E. coli counts above 400 counts / 100 mℓ

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Managing risk internationally

  • WHO –
  • Australian guidelines for

water recycling

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Can it work in SA?

  • What does a DALY mean?
  • The disability-adjusted life year (DALY) is a measure of
  • verall disease burden, expressed as the number of

years lost due to ill-health, disability or early death. It was developed in the 1990s as a way of comparing the

  • verall health and life expectancy of different countries.
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Can it work in SA?

  • Typical reference microorganisms used by WHO

include:

  • Campylobacter - bacteria
  • Rotavirus - viruses
  • Cryptosporidium parvum - protozoa and helminths
  • Some studies have used E.coli as a reference micro-
  • rganism for bacteria – Howard et al.
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Greywater Harvesting Assessment Tool

𝐻𝑋𝑆𝑆 = 𝑁𝐵𝑌 𝑉𝑈𝑆 − 𝑈𝑆𝑆𝑇1 + 𝑈𝑆𝑆𝑇𝑜 + …

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Thematic mapping session

Kirsty Carden Greywater harvesting Workshop 1 18 April 2016

www.wsud.co.za

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Timeline of greywater research

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Legislative issues

  • What legislation is relevant?
  • How important is a legislative framework?
  • Should legislation be developed?
  • What about enforcement?
  • Are there any relevant building codes?
  • What about plumbing ‘sign-off’ on home-based

systems?

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Socio-cultural issues

  • Are socio-cultural-religious considerations

important?

  • What are the most important socio-cultural

concerns?

  • What are the most important ‘influencers’ of social

acceptance?

  • Who are appropriate users?
  • What are the likely behavioural impacts?
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Appropriate applications / uses

  • What are appropriate uses?
  • What are inappropriate uses?
  • Is scale important when designing a greywater

system?

  • How do you decide which risk preventative barriers

to adopt?

  • Is greywater harvesting appropriate in both serviced

and un-serviced settlements?

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Health aspects

  • Is greywater a health risk?
  • What are the pathways to infection?
  • What preventative barriers are there?
  • What about treatment options?
  • Is hygiene education important?
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Key design considerations

  • What are the key technical design considerations?
  • Centralised or decentralised systems; i.e. scale?
  • Are there specific considerations related to quantity

and quality?

  • Are there basic handling rules for greywater?
  • What are the operation and maintenance issues?
  • Is economic viability important?
  • Are there potential impacts on other water services?
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Risk Management / Quantification

  • Why have previous guidelines not been widely

adopted?

  • Are guidelines useful for managing risk?
  • Is the WHO approach to risk management useful?
  • What are the simplest ways to manage risk?
  • Is the “Greywater Harvesting Assessment tool” a

good idea in principle?

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Thank you

To add to the debate go to www.wsud.co.za