BWSSB's wrong approach

Bengaluru’s wastewater woes—stinking rivers, fish kills, and froth and fire on lake spillways—have attracted global attention. This notoriety has triggered various policy responses. Mandating large apartment and commercial buildings to treat and reuse their wastewater has been one such response. Scarcity of fresh water lends support to this idea as wastewater reuse can reduce freshwater demand as well

Apartments struggle with 'manage your own sewage' rule

Bengaluru's bruhath problem with sewage is notoriously well known, with pictures of foaming lakes and fish kills attracting global media attention. But what is less well known is the fact that this city has the highest number of apartment-scale sewage treatment plants (STPs) in the country

Managing HBM’s bandwidth in Multi-Die FPGAs using Overlay NoCs

We can improve HBM bandwidth distribution and utilization on a multi-die FPGA like Xilinx Alveo U280 by using Overlay Network-on-Chips (NoCs). HBM in Xilinx Alveo U280 offers 8GBs of memory capacity with a theoretical maximum bandwidth of 460 GBps, but all the thirty-two HBM ports in Xilinx Alveo U280 are exposed to the FPGA fabric in only one die. As a result, processing elements assigned to other dies must use the scarcely available and challenging to use Super Long Lines (SLL) to access the HBM’s bandwidth. Furthermore, HBM is fractured internally into thirty-two smaller memories called pseudo channels. They are connected together by a hardened and flawed cross-bar, which enables global accesses from any of the HBM ports, but introduces several throughput bottlenecks, degrading the achievable throughput when the entire memory space is used. An Overlay Hybrid NoC combining the features of Hoplite and Butterfly Fat Trees (BFT) NoC offers a high-frequency solution for distributing HBM’s bandwidth across all three dies, as well as overcoming the throughput bottleneck introduced by the internal cross-bar. The Hybrid NoC combines multiple high-frequency Ring NoCs for inter-die communication and Butterfly Fat tree NoCs for intra-die communication. In addition, the routing capability of the NoC can be modified to supplant the HBM’s internal cross-bar for global accesses. We demonstrate this in Xilinx Alveo 280 using synthetic benchmarks and two application-based benchmarks, Dense matrix-matrix multiplication (DMM) and Sparse Matrix-Vector multiplication (SPMV). Our experiments show that NoCs can improve throughput utilization by as much as ×8.6 for single-flit global accesses,×1.7 for multi-flit global accesses with burst length 16, and as much as ×1.4 for SpMV benchmark

An experimental study of pressure drop characteristics in vertical upward two phase and three phase flows

Master'sMASTER OF ENGINEERIN

Improved Performance by Combining Web Pre-Fetching Using Clustering with Web Caching Based on SVM Learning Method

Combining Web caching and Web pre-fetching results in improving the bandwidth utilization, reducing the load on the origin server and reducing the delay incurred in accessing information. Web pre-fetching is the process of fetching the Web objects from the origin server which has more likelihood of being used in future. The fetched contents are stored in the cache. Web caching is the process of storing the popular objects ”closer” to the user so that they can be retrieved faster. In the literature many interesting works have been carried out separately for Web caching and Web pre-fetching. In this work, clustering technique is used for pre-fetching and SVM-LRU technique forWeb caching and the performance is measured in terms of Hit Ratio (HR) and Byte Hit Ratio (BHR). With the help of real data, it is demonstrated that the above approach is superior to the method of combining clustering based prefetching technique with traditional LRU page replacement method for Web caching

Decentralized Wastewater Systems in Bengaluru, India: Success or Failure?

Decentralized wastewater treatment and reuse (DWTRU) using small-scale on-site sewage treatment plants (STPs) is an attractive solution addressing the problems of water pollution and scarcity, especially in rapidly urbanizing cities in developing countries, where centralized infrastructure for wastewater treatment is inadequate. But decentralized systems face several challenges (economic feasibility, public acceptance) that need to be better understood. The city of Bengaluru in India provides an excellent opportunity to evaluate such systems. In 2004, in an effort to curb the alarming levels of pollution in its water bodies due to untreated sewage disposal, the environmental regulatory agency mandated apartment complexes above a certain size to install STPs and reuse 100% of their wastewater, resulting in the installation of more than 2200 on-site STPs till date. This study attempts to analyze the factors influencing the extent of treatment and reuse in such systems, through structured surveys of residential associations, STP experts and government officials. The results are analyzed using a framework that integrates the technology adoption literature with the monitoring and enforcement literature. The study indicates that, while no apartment complex is able to reuse 100% of its treated water, there exists significant variation across apartment complexes in the level of treatment and reuse (from partial to poor) due to a complex mix of economies of scale, the price of fresh water, the level of enforcement and awareness, and technological choices made under information asymmetry. Only apartments dependent on expensive tanker water supply had clear economic incentives to comply with the order. Yet many large complexes that depended on low-priced utility or borewell supply were partially compliant, owing partly to lower (although positive) costs, higher level of formal enforcement and perhaps greater environmental awareness. On the other hand, the high treatment cost pushed smaller complexes to curtail the operation of their STPs (and the lower levels of enforcement further worsened this), resulting in inadequate treated water quality and consequently low reuse levels. The study recommends relaxing the infeasible 100% reuse criterion, and raising the threshold size above which DWTRU should be mandated so as to reduce the cost burden and increase enforceability. Subsidies towards capital costs and enabling resale of treated water will enable wider adoption. DWTRU is an apparently attractive solution that however, requires judicious policy-making and implementation to succeed

Removal of total phosphorus, ammonia nitrogen and organic carbon from non-sterile municipal wastewater with Trametes versicolor and Aspergillus luchuensis

Discharge of organic load from treated wastewater may cause environmental eutrophication. Recently, fungi have gained much attention due to their removal of pharmaceutical substances by enzymatic degradation and adsorption. However, the fungal effect in removing nutrients is less investigated. Therefore, two fungal species, the white-rot fungus T. versicolor as a laboratory strain and the mold A. luchuensis as an environmental isolate from the municipal wastewater treatment plant, were studied to determine the fungal potential for phosphorus, nitrogen, and the total organic carbon removal from municipal wastewater, carrying out a batch scale experiment to a fluidized bed pelleted bioreactor. During the batch scale experiment, the total removal (99.9 %) of phosphorus by T. versicolor was attained after a 6 hours-long incubation period while the maximal removal efficiency (99.9 %) for phosphorus from A. luchuensis was gained after an incubation period of 24 hours.  Furthermore, both fungi showed that the pH adjustment to 5.5 kept the concentration of nitrogen constant and stabilized the total organic carbon reduction process for the entire incubation period. The results from the fluidized bed bioreactor demonstrated opposite tendencies on a nutrient removal comparing to a batch experiment where no significant effect on phosphorus, nitrogen, and total organics carbon reduction was observed. The obtained results from this study of batch and fluidized bed bioreactor experiments are a promising starting point for a successful fungal treatment optimization and application to wastewater treatment.QC 20210107</p

An Energy-Efficient Near-Memory Computing Architecture for CNN Inference at Cache Level

A non-von Neumann Near-Memory Computing architecture, optimized for CNN inference in edge computing, is integrated in the cache memory sub-system of a microcontroller unit. The NMC co-processor is evaluated using an 8-bit fixed-point quantized CNN model, and achieves an accuracy of 98% on the MNIST dataset. A full inference of the CNN model executed on the NMC processor, demonstrates an improvement of more than 34× in performance, and 28× in energy-efficiency, compared to the baseline scenario of a conventional single-core processor. The design achieves a performance of 1.39 GOPS (at 200 MHz) and an energy-efficiency of 49 GOPS/W, with negligible area overhead of less than 1%