OPTIMIZATION PARTICLE SEPARATION FOR BETTER WATER QUALITY IN TREATMENT
The goal of the flocculation, sedimentation, dissolved-air-flotation (DAF) processes are to change the particle size distribution to best suit the subsequent processes. Although several methods exist to evaluate each process, no single universally accepted method has yet to be developed. The purpose of this paper is to present experiences whereby particle counting was used in the diagnosis and optimization of each process. The evaluation is based on particle dynamics, i.e., the change of the number of small and large particles. Some design deficiencies and inappropriate operational conditions in each process have been identified from this method. The effects of changed design in each process have been evaluated by comparing the particle counts at the existing design with particle counts after modification. Because the diagnosis of design may be site-specific, the method presented in this paper will be beneficial in the evaluation of the treatment processes at other water treatment plants leading to low cost, low energy operation.
Integrated design and operation of water treatment facilities
Management of a Design Project. Preliminary Studies. Design of Basic Treatment Process Units. Subordinate Plant Facilities. Design of Plant Components. Elements of Detailed Designs. Specific Water Treatment Processes. Management of Procurement and Construction Phases. Operations and Maintenance Manual and Operator Training. Plant Startup and Follow-Up Services. Appendices. Index.
Submicron polymer structures with X-ray lithography and hot embossing
This article describes the process chain for replication of submicron structures with varying aspect ratios (AR) up to 6 in polymethylmethacrylate (PMMA) by hot embossing to show the capability of the entire LIGA process to fabricate structures with these dimensions. Therefore a 4.7 μm thick layer of MicroChem 950k PMMA A11 resist was spin-coated on a 2.3 μm Ti/TiOx membrane. It was patterned with X-ray lithography at the electron storage ring ANKA (2.5 GeV and λc ≈ 0.4 nm) at a dose of 4 kJ/cm3 using a Si3N4 membrane mask with 2 μm thick gold-absorbers. The samples were developed in GG/BDG and resulted in AR of 6–14. Subsequent nickel plating at 52°C resulted in a 200 μm thick nickel tool of 100 mm diameter, which was used to replicate slit-nozzles and columns in PMMA. Closely packed submicron cavities with AR 6 in the nickel shim were filled to 60% during hot embossing.