- The Filtration Society - http://www.filtsoc.org -

Volume 14, Issue 3

POREX® TUBULAR MEMBRANE FILTER (TMF™) APPLIED IN A PLASTIC PLATING WASTEWATER RECLAIM SYSTEM
Doug Frick (pages 140-145)

A large auto parts manufacturer located in the Zhejiang province of China was in need of a wastewater treatment system to address the complex wastewater produced by their plastic plating processes.  Several streams of heavy metal contaminated wastewater are generated from their workshops that need to be treated before discharge.  In addition, the company is very environmentally conscious and wanted to reduce their overall fresh water consumption by reusing the wastewater from the process.  In 2012, a new system was built by a certified water treatment company to fulfil the client’s expectation for a ‘treat and reuse’ process.

There are four different streams of wastewater (WW) from the customer’s workshop:

  1. 312 m3/day acid/alkaline and copper WW
  2. 144 m3/day nickel WW
  3. 287 m3/day chromium WW
  4. 274 m3/day combined WW (including electroless nickel WW)

These four streams are treated separately with a reaction stage (alkali precipitation and coagulation, plus a reduction stage for chromium WW), Porex Tubular Membrane Filter (TMF™) stage for solid/liquid separation, and single or double pass reverse osmosis (RO) for desalination.  The product water is then sent back to the workshop for reuse as process water.

System commissioning began in October 2012 and performance has met the design standard.  Conductivity of the treated water (for reuse) is less than 10 μS/cm.  The recovery rate of the inner reclaim system is 80%, with the recov­ery rate of the whole factory at 66%.  Final discharge water (RO reject water, with a further treatment process) has met the required limit values and in two months 22,300 m3 of wastewater was reused.  That equates directly to an equal amount of fresh water being saved.  The Porex TMF benefits were demonstrated as a key process linking the wastewater treat­ment system to an RO desalination system.

IMPACT OF POOR DIESEL FUEL QUALITY ON AN URBAN FLEET
Barry Verdegan, Cliff Burbrink, Dakota Johnson, Sherif Abou-Rayan, Henry Amirkhanian and Amit Baddi (pages 145-152)

Modern HPCR diesel engines are more powerful, compact, reliable, quieter, and run cleaner than their predecessors.  Clean fuel is a key enabler to accomplish this.  In 2009, the New York City Transit Authority (NYCTA) experienced a series of failures that underscore the importance of clean fuel and what it takes to achieve it.  Injector deposits and dimensional changes lead to the rash of failures.  The deposits were largely attributed to elevated levels of metal carboxylates in the fuel.  The dimensional changes were the result of abrasive wear caused by particulates in the fuel.  The problems were solved through the use of detergent additives to prevent soap deposits and clean previously stuck injectors.  The use of an advanced fuel filter containing nanofibres was found to improve fuel cleanliness to acceptable levels, even under dynamic operating conditions which are common in urban driving.

INFLUENCE OF WINDING PARAMETERS ON THE PERFORMANCE OF STRING WOUND FILTER CARTRIDGES – PART 2
Someshwar S. Bhattacharya and Pragnya S. Kanade (pages 152-157)

The performance of a string wound filter cartridge is greatly dependent upon its winding conditions as well as the test conditions.  The winding variables have an obvious role to play in the filtration behaviour of any string wound cartridge used in the field.  The transmission ratio (traverse ratio/coil angle), winding on tension and the gain are important winding parameters but other than these, full package diameter, number of circumferential diamonds, speed and yarn count are equally important and play a crucial role in determining filtration behaviour.

This paper deals with the effects of the winding variables and tries to establish their influence on the performance of a string wound filter cartridge tested under otherwise identical conditions.  An attempt is also made to interpret the findings of particle size analyses so as to judge filtration behaviour.  It was found that the change in full package diameter may not be beneficial in all circumstances, whereas the circumferential diamonds formed will affect porosity of the cartridge.  A change in speed has a similar influence to an increase in winding on tension.  The fineness of the feed material is a strong factor but may be rendered ineffective if the fineness of fibres of which it is composed is not changed.

VALIDATION OF ADSORPTIVE FILTERS AND PRESSURISED AIR FILTERS
UNDER EXTENDED OPERATIONAL CONDITIONS
Hartmut Finger, Wolfgang Mölter-Siemens, Stefan Haep and Dieter Bathen (pages 158-163)

This paper describes a range of experimental test facilities and initial results for adsorptive filters and pressurised air filters.  The underlying reasons for developing the apparati are discussed and related to the various relevant testing standards.

CHALLENGES FOR CURRENT AND FUTURE WATER/DIESEL SEPARATION SYSTEMS
Dagmar Winkler, Steffen Schütz, Pius Trautmann, Jochen Reyinger, Uwe Staudacher and Harald Banzhaf (pages 164-174)

The separation of dispersed water droplets from diesel fuel is an essential process in fuel conditioning to protect the sensitive parts of modern diesel injection systems from the damaging results of the water.  The basic design idea of almost all filter solutions for water/diesel separation comprises the serial combination of hydrophilic (water coalescer) and hydrophobic (water barrier) media in various sequences.  Experimental investigations show that a range of dynamic parameters of the water/diesel system as the interfacial tension, the contact angle and the droplet size distribution influence the water separation efficiency.  Computational fluid dynamic (CFD) models for two phase flows with free interfaces are applied to analyse the influence of the flow conditions on droplet separation and release at fibrous filter media.

FOAM-AIDED SLUDGE TREATMENT
Karita Kinnunen-Raudaskoski, Pentti Pirkonen, Jani Lehmonen and Tuomo Hjelt (pages 174-180)

Both industry and domestic households produce huge amounts of wastewater and, as a result, effective sludge management is required.  One route is to reduce the amount of water in the final sludge cake.  This paper introduces a foam-assisted thickening method to improve the effectiveness of biosludge dewatering.  The method, foam-assisted dewatering (FAD), has previously been used in a paper production process in the 1980s.  The current work shows that in both static and dynamic experiments, FAD is also applicable for sludge treatment.  Foam addition to the dewatering process of biosludge from a paper mill increased the dry solids content of the wet cake and shortened the dewatering time.  In addition, the turbidity of the filtrate fell indicating enhanced microparticle retention.  Results could be utilised in industrial belt thickening and the vacuum filtration of slurries.  The expected benefits could be higher dry solids content of filter cakes, a faster dewatering rate and lower flocculent consumption.