8 ML/DAY CONTAINERISED MICROFILTRATION SYSTEM
OUR RENTAL SYSTEMS
MICROFILTRATION SYSTEM FOR POTABLE WATER OR CLEAN APPLICATION
Asset ID MF-001
FOR SOLIDS REMOVAL AND CRYPTOSPORIDIUM PROTECTION
This system was designed to comply with UK drinking water regulations and all components are compliant with regulation 31 of the UK Water supply regulations.
It is capable of removing suspended solids, turbidity, cryptosporidium, bacteria and precipitated iron and manganese from river, borehole, spring or open reservoir water with variable turbidity.
It is installed in 2 separate 40ft shipping containers and contains 4000 square metres of installed membrane area. This means that even when a conservative flux rate is selected (e.g. 90 lmh) – it is capable of producing over 8.6 million litres per day of microfiltered water with turbidity of less than 0.5 ntu
It includes a fully automatic CIP system and wastewater neutralisation
SPECIFICATIONS
- Designed and built by Pall Water in 2008
- Fully automatic operation with variable and operator adjustable filtrate flowrate
- Will run from generator or mains supply (separate incomers are provided for mains or generator)
- Two independent treatment streams in each container – can operate a duty / duty or duty / standby arrangement
- Microza PVDf membranes providing 0.1 µm absolute filtration barrier and with excellent pH tolerance allowing aggressive chemical cleaning
- Fully automatic integrity testing routine in compliance with cryptosporidium operating rules
- Drinking water approved system and components (UK – DWI regulation 31)
- Fully automated clean in place and enhanced flux maintenance routines
- Fully automated wastewater neutralisation and discharge
- 2 no. 300 micron self-cleaning pre-screens in each system
- Mitsubishi PLC and touch screen HMI operation
- Continuous monitoring of filtrate quality for turbidity and conductivity
| System manufacturer | Pall Water (formerly Pall Corporation) |
| Membrane type | Microza UNA-620C PVDF microfiltration membrane (Asahi Corporation) |
| Membrane are per module | 50 m2 |
| Membrane pore size | 0.1 µm |
| Number of installed membranes | 80 per system (total installed filtration area per system is 4000 m2 |
| Design flow rate (product) | 8 Ml/d per system |
| Waste yield | Between 1-2% of throughput depending upon the feed turbidity (and therefore backwash frequency) |
| Flux rate (normal filtration) to provide 8 ml/d of output | 83 ‘lmh’ |
| Flux rate (reverse filtration) | 40 ‘lmh’ |
| Clean-in-place tank size | 6.4 m3 |
| External Feed pump | Wet sump or borehole pump, variable speed (not included) |
| Reverse filtration (backwash) pump | Centrifugal variable speed |
| CIP pump type | Centrifugal split ring fixed speed |
| Chemicals required for operation of the process | Sodium hypochlorite 14/15% to BS:EN 901:2013 Sodium bisulphite liquor 38%. To BS:EN 12121:2012 Citric acid 50%: food grade (or other suitable acid) Sodium hydroxide liquor 32%: To BS:EN 896:2012 |
The following items are required to run the systems on any particular site
Item | Further details |
Feed pump and feed tank | A suitable feed tank is required if the system is not fed directly from a borehole or submersible pump located in a wet wellThe feed pump is wired to its variable speed controller at an external connection box. The system can be fed from submersible pump in borehole, spring tank or any other wet well. Alternatively any dry well feed pump could be used that is compatible with the variable frequency drive
Important note: The feed pump is not included in the system supply but can be arranged |
Wastewater system for dirty backwash water | Pipework and connection to a system for the accommodation of non-chemical wastewater (backwash), properly braced to withstand the surges or mixed flows of wastewater and air. The volume of wastewater generated for each backwash is approximately 1.5 m3.
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Wastewater system for neutralised chemical wastewater | Pipework and connection to a sewer or holding tank for neutralised chemical wastewater (suggested size of 50m3 plus level instrumentation) |
Electrical supply | 150 KVA rated supply by generator or mains feed |
Weights and load distribution | The membrane container is 11600 kg gross weight and evenly distributed The service container is 11300 kg gross weight and evenly distributed |
PROCESS DESCRIPTION
Pressurised feed water is provided by a single external feed water pump to the membrane container (borehole, dry well or submersible pumps can all be used) and is processed in two separate streams that operate independently of each other. Each stream consists of 40 microfiltration membrane modules with 50 m2 of active membrane area in each module.
Filtrate water quality is monitored for turbidity and conductivity by instruments in the membrane container. Turbidity of the filtered water should be always less than 0.5 NTU irrespective of the feed water quality.
The membranes are maintained in operation by an automatic ‘flux maintenance’ (FM) operation comprising an ~ hourly* backwashing (or ‘reverse filtration’) sequence supported by daily* ‘enhanced flux maintenance’ (a chemically enhanced backwash) and weekly* chemical cleaning.
Wastewater generated by the system consists of; 1) non-chemical wastewater – backwash waste from the membranes and the pre-screens containing suspended solids, and 2) Fully neutralised chemical cleaning solutions[1] which are suitable for discharge to public sewer without further treatment.
These systems will provide removal of suspended solids, bacteria and cryptosporidium. For potable water supply additional treatment may be required for the removal of pesticides, nitrates, taste, odour or any other contaminant present in the feed water that is not removed by a microfiltration membrane. Final disinfection by chlorine will be required in water supply networks.
The systems are fully automated once started. All backwashing, chemical cleaning and neutralisation/discharge is carried out automatically.
[1] neutralised solutions of sodium hypochlorite (neutralised with sodium bisulphite) and sodium hydroxide neutralised with citric or hydrochloric acid.
Item | Number installed and further details |
Main electrical panel | Provides power and controls for: • External feed water pump with variable frequency drive (Siemens Micromaster) • Reverse filtration pump with variable frequency drive (Siemens micromaster) • Chemical cleaning pump with fixed speed operation • Immersion heaters in CIP tank (3 No.) • Automatic backwashing fine strainers (2 No.) |
CIP tank | 5.4 m3 capacity, three x 3 kW immersion heaters installed Analogue and digital level instrumentation |
Clean backwash (RF) tank | Approx 2.0 m3 capacity Analogue and digital level instrumentation |
Reverse filtration pump | Centrifugal |
Clean-in-place pump | Centrifugal split ring type |
Clean in place and neutralisation instruments | pH, conductivity and redox by ABB |
Chemical dosing enclosures | 4 separate enclosures with integral bunds, loading pump (air driven diaphragm) and dispensing pump (air driven diaphragm) and 200 litre containers for chemical concentrate with low level probes |
Compressor | Atlas Copco SF8FF |
Item | Number installed |
Self cleaning 300 micron screen (Atkins Fulford) | 2 |
Membrane element (Microza UNA-620C DWI reg 31 listed) | 80 |
Control panel with HMI and PLC (Mitsubishi) | 1 |
Air receivers | 2 |
Air pressure regulators | 3 |
Ffesto block pneumatic valve control | 2 |
Filtrate flowmeter | 2 |
Turbidity meter by ABB | 2 |
Conductivity meter by ABB | 1 |
Preservative pump | 1 |
Pipework, manifolds, valves, instrumentation |
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