In the UK our water supplies are of the highest quality and expensively purified before they reach the householder. We use approximately 150 litres of water per person per day; this is despite the fact that a large proportion of the water used can be of a lower grade. This harvested water can then be used for flushing toilets, washing machines, watering gardens and cleaning cars. The demands on drinking water can then be greatly reduced.

Rainwater can be harvested in any situation where non- potable water is required. The system is ideally suited for private, industrial, commercial, educational and agricultural situations. It provides cost saving benefits, whilst contributing to the protection of a key natural resource.

The Oasis system is manufactured using only products proven for their reliability and efficiency.

The storage tanks are manufactured in pre-cast reinforced concrete and benefit from a 120 year design life therefore giving long term peace of mind concerning durability of our storage chambers/tanks.

Germany is the leader in the world market concerning Rainwater Harvesting and Greywater Recycling and 70% of Storage tanks used are supplied in pre-cast concrete.

CPM Group Ltd is a founder member of the UK Rainwater Harvesting Association.

To combat these problems the Environment Agency has been promoting the use of Sustainable Urban Drainage solutions (SUDS). The Planning Policy Guidance Note 25 for England on Development and Flooding, emphasises the role of SUDS and introduces a general presumption that they will be used. SUDS will probably feature increasingly in such guidance documents, as they are revised.

SUDS is a process for achieving integrated surface water drainage design with the objectives of:

1. Reducing the risk of flooding from developments.

2. Minimising pollution arising from surface water runoff to groundwater.

3. Maintaining recharge to groundwater.

4. Better use of water resources.

5. Improvement to water amenity & biodiversity.

Using rainwater harvesting is just one way of approaching the problem of sustainable development and has a viable role to play in water conservation.

CPM Group Ltd has a full range of environmentally innovative products that help in the design of the SUDS systems.

The Oasis system is designed using the very best equipment to provide cleaned rainwater with the minimum of maintenance. Water quality is maintained by the removal of organic matter and also by the action of the incoming water through the calmed inlet which introduces oxygen into the stored water. Rainwater is very soft and chlorine free, making it excellent for washing machines.

The Greywater system uses ultra- filtration membrane ISB technology, to treat bath, shower and hand basin waste water - which is then used to flush toilets and can be used for watering the garden. Approximately 70 litres of drinking water and 44 litres of waste water can be saved per person per day in domestic households, and significantly more in hotels.

Reusing water reduces drinking water and waste water costs. The Greywater recycling therefore pays for itself in just a few years. The main advantage is that this system does not depend on rainfall for it to flush the toilet or water the garden. In fact the greywater system is simply using the water that has already been paid for - pay once use twice!

This system is also available as a combined rainwater harvesting and greywater recycling system. This is especially efficient where peak demand such as garden irrigation is planned.

The system can also be used for Industrial, Commercial & Hotel applications. The treatment process for a larger facility is divided into four steps: Pre-treatment, aerobic treatment, membrane filtration and clear water storage .

The system treats the water to a quality which complies with the standard of the EU-guideline for bathing water.

The gravity-effect in combination with air bubbles ensures a continuous flow of filtrate and thus long service life with low maintenance. After the filtration, the water is supplied to the desired applications. If there is a lack of treated greywater, the system will automatically switch over to mains water.

Combining the two technologies not only adds the positive aspects of each system but also reduces cost.

The Oasis Commercial system uses the tried and tested Storm Attenuation storage pipe components, which can withstand traffic loading conditions.

The Commercial system uses the same arrangements as the domestic arrangement but the components are on a larger scale due the greater water harvesting capabilities and tend to use more sophisticated equipment.

The economics of scale, when using a rainwater harvesting system in industrial, commercial and or educational situations can mean substantial savings and reduced pay back periods.

Because CPM Group Ltd is the leading supplier of pre-cast concrete drainage in the UK, this means we have the largest range of storage systems available for Rainwater & Greywater harvesting.

• The standard Oasis Chamber capacity starts at 1500 litres.
• The CPM Oasis Chamber is fabricated using a base unit complying with BS EN 1917: 2002.
• The chamber is reinforced to ensure structural integrity.
• The concrete chamber units are manufactured using a combined Portland cement and pfa. This meets Design Class 4 sulphate conditions as defined in BRE Special Digest 'Concrete in Aggressive Ground' Part 4 Design for Specific Precast Products.
• Can be installed in trafficked areas, all Chambers supplied with HD Cover Slab.
• Speedy installation, chamber can be installed within the hour.
• Floatation is not a problem in waterlogged ground.
• Requires no in-situ concrete base. A 3000 litres GRP tank would require a minimum of 6m³ of ready- mixed concrete to surround it.
• The chamber requires no granular backfill, as dug material can be used.
• The chamber does not require to be filled with water when back filling unlike other tank materials
• Chamber benefits from a 120 year design life.

The management of the Rainwater Harvesting system can be a very simple arrangement or can be a sophisticated microprocessor controlled system.

The top of the range management system we provide is an IRM®-Rainmanager RMC which guarantees the system operates safely. The Rainmanager is housed in a neat compact control box and includes electronic control, centrifugal pump, and mains water back up value.

The filters are used to remove debris i.e. leafs, silts etc from the harvested rainwater before it reaches the storage tank. Further filtration is used before the harvested rainwater is supplied via the pump; this floating filter arrangement inside the tank, ensures that the rainwater is always extracted from the cleanest part of the tank.

Filter types vary from internal tank filters to external vortex filters to large commercial filters. The filter used will depend on whether they are for domestic or commercial properties and provide for roof areas from 150m˛ to 40,000m˛. All of the filters used are of highest quality, with a proven track record in reliability and efficiency. Some filters can even be fitted with a back wash facility to reduce the maintenance requirements.

When there are periods of dry weather, the rainwater can be backed up with mains water to ensure continuity of supply. All the systems have the water regulatory 'Air Gap' to ensure no cross contamination between the two water supplies. Another variation available for the domestic arrangements is a header tank design which is fitted with dual inlet valves. The header tank arrangement can be used to overcome the potential loss of supply during times of power failure.