Rainwater Reclamation CPD Seminar
Presented by Matthew Tickle
to
Suffolk and Essex
Energy & Environment Group
stormsaver.com
Stormsaver
Manufacturer and supplier of Stormsaver rainwater recovery systems
Solve drainage problems, minimise localised flood risks and save
money by recycling rainwater which would otherwise go to drain.
stormsaver.com
Presentation Overview
 Rainwater Facts
 Typical uses
 Lessons from Germany
 Typical Installation and Filtration
 Amount of Water to Collect
 Payback and Case Studies
 Why use a Specialist
stormsaver.com
Rainwater Facts
 There is 18 times more rainfall in the UK than the net consumption of the
population – more than enough for our needs!
 When combined with attenuation, rainwater recovery helps to reduce potential
flood risks. Synergy with Sustainable Drainage Scheme (SDS)
 Up to 50% of water in most commercial, domestic or industrial applications can
be supplied by rainwater rather than mains water
 Rainwater is FREE – save money on your water bill.
 Positive impact on the environment – BREEAM Points
 Utilising recycled rainwater helps to reduce potential water shortages.
stormsaver.com
Rainwater or Grey water ?
 Rainwater
 Grey water
Original source of all water
supplies. Reservoirs,rivers,
aquifers.
Rainwater systems collect
water from roof and/or
surrounding area before it
drains away.
Wastewater from sinks, baths,
showers, domestic appliances,
except sink and dishwasher
wastewater.
System collects water before
it reaches the sewer/drain.
stormsaver.com
Typical uses in a Domestic /
Commercial building
Recycled rainwater can be used for;
 Garden watering
 Vehicle washing
 Toilet flushing
 Urinal flushing
 Washing machines
 Property cleaning (window washing, hosing down)
stormsaver.com
Lessons from Germany





Mains water costs are 2-3 times higher.
Rainwater systems for 15 –20 years
>2,300,000 systems installed.
Mandatory installation in some areas for new builds.
Subsidies available up to £1000/system
stormsaver.com
General design and
installation principles
Rainwater collected from roof area
Pre-tank filter
Stormsaver® storage tank
Inlet calmer
Submersible pump
Floating suction filter
Level sensors
Stormsaver® rain processor unit
Stormsaver® header tank
Mains water top-up
stormsaver.com
Disinfection.
 UV – requires low turbidity, removal of particles to prevent
sheltering of organisms. On all the time.
 Electricity costs and replacement bulbs costly : ~ 200 kWh per
year : more economic the more water is treated.
 Ionisation : Trace elements used to sterilise water, lower energy
costs, replacement electrodes.
stormsaver.com
Filtration
 Filtration is key to good water quality.
 “prevention or removal of organic debris before storing
rainwater was found to be important in maintaining good
water quality” BSRIA TN 7/2001.
3 stage process :
Stage 1 : pre tank 440 microns
Stage 2 : pump
180 microns
Stage 3 : processor 35 microns
stormsaver.com
How much water is collected ?
 The larger the roof area and the demand, the greater the
financial savings.
Vol. Collected m3 =
roof area m2 x ave. annual rainfall
x collection co-efficient x
filtration co-efficient
Pitched ~ 90%
Flat ~50%
stormsaver.com
Information required to
size a system
What is the usable roof area?
What is the type of building? School, prison, residential etc.
What is the site post code / location?
What is the demand of the building? Either in L/S, number of
W/C’s or occupancy. Also what are the operating hours?
 What is the type of roof drainage? Syphonic or gravity. If syphonic
what is the flow rate?
 Is there room for a header tank or will it require a pressure boosted
system?
 Do you require UV Disinfection?




stormsaver.com
Other Considerations
 A syphonic break is required before the pre tank
filter if building has a syphonic roof drainage
system such as Fullflow.
 Fall across pre tank filter and tank- 400mm.
 Rainwater recovery systems do require a degree of
maintenance.
stormsaver.com
Savings and payback
‘Reduce the spiraling cost of water’
Cost of water is increasing as demand
for supply increases.
Most commercial systems see an
efficiency of between 50-75%
Return on capital cost and installation
usually within 5-10 years
Enhanced Capital Allowance (ECA)
approved
stormsaver.com
Case Studies
ASDA – Falkirk, Scotland
Application
Crate Wash
Roof Area
5900 sqm
Demand
25m3/day
Efficiency
51%
Saving p/a
£8390
Location
Scotland
stormsaver.com
Case Studies
Conifers School, Weymouth
Application
WCs
Roof Area
1918 sqm
Occupants
450
Efficiency
41%
Saving p/a
£1245
Location
Dorset
stormsaver.com
Case Studies
Royal Bank of Scotland HQ
Application
WCs
Roof Area
17000 sqm
Occupants
3000
Efficiency
62%
Saving p/a
£15,770
Location
Scotland
stormsaver.com
Useful publications


“Rainwater and grey water use in buildings – best
practice guidance” 2001 : CIRIA C539
“Rainwater and grey water in buildings – project report
and case studies.”2001 : BSRIA TN7/2001

CIRIA Research Project 555 – SUDS

WRAS: Guidance Notes: 1999- 9-02-04 and 9-02-05
stormsaver.com
Using a rainwater recovery
specialist





Consultation with architects, consultants, mechanical engineers
Bespoke design
Site surveys / visits during installation.
System commissioning
Full service and maintenance contracts
Our friendly, fully trained technical
staff offer support before, during
and after installation
stormsaver.com
Presentation Review
 Rainwater Facts
 Typical uses
 Lessons from Germany
 Typical Installation
 Filtration
 Amount of Water to Collect
 Payback
 Case Studies
 Why use a Specialist
stormsaver.com
Stormsaver
Stormsaver would like to thank you for the
opportunity to speak at this event and look forward to
answering any of your questions.
Visit our web site at www.stormsaver.com
stormsaver.com