CEE April-June 2012

This out-to-in configuration is particularly advantageous where the surface water encounters spikes in turbidity due to monsoon seasons and flash floods (this also applies for effluenUsewage recycling applications due to the high possibility of surges in the TOC and turbidity of effluent arising from batch processes. This can be seen in the third– party study by China Water Network (Figure 3) which illustrates that the irrecoverable flux decay in out-to-in membranes occurs at a significantly slower rate than in-to-out membranes. 1110 Unlike dead-end filtration where foulants are continually pressed against the walls of the membrane, the cross - flow configuration maintains a minimum cross - flow velocity by recirculating the reject stream. This re– circulation creates cross– 700 DEAD END flow shear, which keeps the solids present in the feed water in suspension , and prevents the accumulation of solids on the surface of the membrane. It is also possible for the balance of the reject stream to be bled-off to prevent the build-up of solids in the re-circulation loop during periods of high turbidity. Such feed and bleed operation allows the UF operate continuously before the need for backwash , thereby improving recovery and availability of the system even when filtering very challenging feed-water. The pretreatment of choice In conclusion, the Krista!® UF hollow fiber membrane is specifically tailored for power sector applications. Made of modified hydrophilic polymeric material, this range has a stable asymmetric structure that certifies long term reliability. This feature also ensures consistent removal efficiency, resistance to cleaning chemicals commonly used during membrane maintenance and recovery processes, and maintains a high permeate flux, all of which caters to a wide variety of feed– water conditions. With an average membrane area of 60 m 2 and high permeate flux, these membranes are also manufactured in shorter 1.2 m modules for a wider variety of options for varied applications. Regardless of length , every model has the ability to operate in a wide pH and temperature range. In addition, with a molecular weight cut-off ( MWCO) range of 10,000 Da to 150,000 Da, suspended solids, such as colloidal silica and Cryptosporidium that are the main causes of boiler CROSS FLOW Feed Permeate ReJe<:l to recirculatJon or bleed scaling are easily removed resulting in consistent permeate turbidity and SDI values of less than 0.2 NTU and 2 respectively, which surpasses international industry standards for power plants worldwide. Courtesy: Water Today, Feb. 2012 Pp 18-22. Energy Efficiency &Conservation Energy Efficiency ENERGY VALUE Cement industry's efficiency improvement initiatives The cement industry plays a critical role in infrastructure development. Cement is key input for construction activities in various sectors including power, real estate, ports and logistics. India is the second largest cement producer in the world after China. The industry has a total installed capacity of about 300 million tonnes (mt), which is more than sufficient to cater to the domestic demand. Cement demand has declined over the past year mainly due to slow growth in the infrastructure and real estate segments. However, during 2012-13, this demand is expected to grow by around 8 per cent considering an overall increase in construction activity. Of late, factors such as an increase in fuel prices, 32