CLOSED-LOOP PRE-TREATMENT CLEANING (CPC)

BG 29/2021 is the BSRIA guide that provides the latest advice on pre-commission cleaning; an essential process that helps water systems perform at their optimum.

System contaminants need to be removed by a combination of chemical cleaning and high velocity flushing. This will then allow the on-going water treatment regime to work effectively in preventing corrosion and microbiological fouling.

Closed-loop pre-treatment cleaning (CPC) methods may assist in reducing bacterial contamination and corrosion after the initial fill and during system pressure testing.

 

Water savings can be achieved by employing high-flow side-stream filters, or full-bore filters during balanced and dynamic flushing. This enables recirculation of flushing water, thereby reducing the discharge to drain.

BSRIA 29

Closed-loop pre-treatment cleaning (CPC) offers an effective method for cleansing installations by employing chemically treated water, circulated dynamically through deep-bed filter media housings to eliminate contaminants.

Additionally, non-chemical pre-treatment methods such as ultraviolet or bacteriological removal equipment can be used to treat the fill water.

This approach eliminates the necessity for chemical cleaning.

CPC presents several advantages, including reduced water consumption, potential environmental benefits by either effluent-free or reduced-effluent processes, and minimal water requirement limited to system filling and temporary cleaning equipment.

This method proves beneficial in scenarios with insufficient water supplies, demineralized or softened fill water is utilised, or draining the system is impractical. Moreover, CPC can streamline projects with fewer stages and provide flexibility, particularly in large projects with phased completion.

The filling process involves pre-treating the initial fill water with chemicals to mobilise contaminants and provide corrosion and microbiological protection. This treated water is then circulated through the system via filter media to remove solids with minimal flushing.

A purpose-built pre-treatment rig, including adjustable proportional dosing equipment, microbiological reduction apparatus, failsafe mechanisms, and testing points, ensures optimal corrosion and microbiological protection during filling.

Testing of fill water during and after filling confirms proper functioning of pre-treatment equipment and adherence to chemical and microbiological parameters. Standard test kits and laboratory analysis may be employed for this purpose.

Thorough venting procedures and temporary conditioning units are utilised during filling to remove contaminants. The conditioning unit, fitted with flow measurement devices, facilitates dynamic flushing velocities, with temporary deaeration equipment connected to prevent corrosion.

Flushing water is directed through the conditioning unit to remove debris via the filter media, and the cleaning process can be conducted either on a side-stream or full-flow basis, with full-flow preferred to prevent contaminant recirculation.

Final flushing through plant items and terminal units may be necessary based on our recommendations to ensure completion of the process.

Following any cleaning exercise it is important that closed systems are carefully monitored and regularly maintained. This maintenance should continue throughout the life of the building and should involve sample taking at a maximum interval of 3 months.

“PH WATER TECHNOLOGIES ARE A DESIGNER AND SUPPLIER OF AN EXTENSIVE RANGE OF WATER TREATMENT PLANT AND EQUIPMENT INCLUDING WATER SOFTENERS, WATER CONDITIONERS, CHEMICAL DOSING SYSTEMS, DEMINERALISERS, SAMPLE COOLERS, WATER FILTERS, UV AND REVERSE OSMOSIS SYSTEMS”.

Aqua servamus

A purpose-built pre-treatment rig, including adjustable proportional dosing equipment, microbiological reduction apparatus, failsafe mechanisms, and testing points, ensures optimal corrosion and microbiological protection during filling.

Testing of fill water during and after filling confirms proper functioning of pre-treatment equipment and adherence to chemical and microbiological parameters. Standard test kits and laboratory analysis may be employed for this purpose.

Thorough venting procedures and temporary conditioning units are utilized during filling to remove contaminants. The conditioning unit, fitted with flow measurement devices, facilitates dynamic flushing velocities, with temporary deaeration equipment connected to prevent corrosion.

Flushing water is directed through the conditioning unit to remove debris via the filter media, and the cleaning process can be conducted either on a side-stream or full-flow basis, with full-flow preferred to prevent contaminant recirculation.

Final flushing through plant items and terminal units may be necessary based on the cleaning specialist’s recommendations to ensure completion of the process.

We have developed our own specialised filtration unit designed solely to minimise/eliminate mass water loss water from closed systems during the ‘pre-commission cleaning process. It is also perfect solution for flushing systems where there is an inadequate water supply or problems arise due to site restrictions for discharging trade effluent.

boasts a bacteria block and offers our clients a much greener solution as it can save water during all flushing procedures (including localised forward flushing and backflushing) and therefore all works can be completed following the principles laid down within the BSRIA BG 29/2021 guide.

On one of our projects over 27 million gallons of water was used for flushing/cleaning purposes and we believe that using this methodology will revolutionise the Pre-Commission Cleaning industry.

To get the full benefit; this equipment must be installed and used during the filling and testing procedures and contractors must ensure that the coils are not wetted during the process.

The units have a pre filter (highest micron), intermediate filter and final filter (bacteria block, lowest micron). These units can also be fitted with in-line UV and skid mounted if required and can either be purchased or hired for the duration of the chemical cleaning project.

There are no micro-organisms known to be resistant to UV light. UV is known to be highly effective against bacteria, viruses, algae, moulds and yeasts. In practice, for most microorganisms, the removal efficiency of UV for microbiological contaminants such as bacteria and virus generally exceed 99.99%. Where UV is specified, then this would be installed after the filters to maintain effectiveness and ensure that any sediment and other contaminants within the water which could create a “shadow” are removed.

On completion of our works and receipt of satisfactory results the unit can be removed or alternatively it can be left online to help maintain water quality during the commissioning process.

Units are available from 50mm upwards.