The vortex concentrator for suspended solids treatment.

The use of vortex concentrators is becoming increasingly popular for suspended solids reduction in combined sewer overflows and stormwater. This study is a laboratory investigation of the use of vortex concentrators to reduce the solids concentration of synthesized stormwater. The synthesized stormwater was made with water and addition of particles; sand, granular activated carbon, and sewer sediments. The vortex concentrator was made of acryl resin 300 mm in diameter. To determine the efficiency for various influent suspended solids (SS) concentrations, tests were performed with different SS concentrations. The samples were taken simultaneously at the influent storage tank and effluent tank, and measured SS concentrations. The range of surface loading rates were 120 to 850 m3/m2/day, and influent SS concentrations were varied from 300 to 5,000 mg/L. To determine the optimum coagulant dosage, jar tests were conducted with coagulants such as PAM and PAC. It was found that optimum coagulant and its dosage were PAM and 2 mg/L. The overall SS removal efficiency of the vortex concentrator for typical stormwater was estimated at about 65%. With an increase of SS concentration, the removal efficiency was increased. Since the SS concentration of stormwater was higher than 1,000 mg/L, the removal efficiency of the vortex concentrator for stormwater could be estimated to be 65-70%. The SS removal efficiency was increased with an increase of retention time, and the optimum retention time was 0.15-1.0 minutes. With an increase of the foul to overflow Q(F)/Q(o), a key parameter for vortex concentrator operation, the removal efficiency was increased. An alternative solution to improve treatment efficiency might be to set a follow-up retention basin. Based on a series of settling tests on the treated overflow water from the vortex concentrator, 5 to 10 minutes hydraulic retention time in a follow-up retention basin would substantially improve the results.

First flush analysis of urban storm runoff.

Stormwater runoff was monitored on 13 separate urban watersheds, which were chosen to represent distinct types of residential and industrial development, along with various watershed characteristics. A total of 38 storm events were monitored to investigate the first flush phenomenon. The first flush phenomenon may be defined as the initial period of stormwater runoff during which the concentration of pollutants is substantially higher than during later stages. The magnitude of the first flush phenomenon, and if it actually occurs, was calculated using a method of data analysis which results in determining the 'event mean concentration' (EMC). The magnitude of the first flush phenomenon was found to be greater for some pollutants (e.g. suspended solids from residential areas) and less for others (e.g. chemical oxygen demand from industrial areas). No correlation was observed between the first flush phenomenon and the antecedent dry weather period, however, the first flush phenomenon was greater for smaller watershed areas.

Autoimmune disease and chronic lymphocytic leukemia: autoimmune hemolytic anemia, pure red cell aplasia, and autoimmune thrombocytopenia.

Immune dysregulation, a hallmark of chronic lymphocytic leukemia (CLL), manifests itself in three autoimmune diseases: warm autoimmune hemolytic anemia (AIHA); idiopathic thrombocytopenia (ITP); and, pure red cell aplasia (PRCA). AIHA occurs in 11% of advanced stage CLL patients. Prednisone is the first treatment of choice, with 90% responses and 65% complete responses. More than 60% of patients relapse when treatment is stopped. Intravenous immunoglobulin, the next line of treatment, causes responses in 40% of patients. While the data are very limited, cyclosporine A is a reasonable choice for third-line therapy. Alkylating agents, danazol, plasma exchange, immunoabsorption, vincristine-loaded platelets, splenectomy, and splenic irradiation are also reported to cause responses. The data on mechanisms of AIHA are most consistent with immune dysregulation leading to loss of tolerance to a self antigen which in turn leads to the immune-based hemolytic anemia. PRCA is underrecognized in CLL with 6% of CLL patients having PRCA when tested for it. Unlike AIHA, PRCA often occurs in early stage disease. Anemia, reticulocytopenia, and a marrow virtually devoid of red blood cell precursors are hallmarks of PRCA. Corticosteroid therapy is the first line of treatment. If a response is not obtained in 4 weeks, cyclosporine A should be added. Although the data on pathophysiology are very limited, PRCA appears to be the result of an abnormal T cell that both fails in its normal function to support growth and inhibits the growth of erythroid progenitor cells. ITP occurs in 2-3% of CLL patients, occurs in early stage disease and may be a presenting manifestation. Initial therapy for ITP mirrors the guidelines for primary ITP. Initial therapy should consist of prednisone. Seventy percent of patients respond. Splenectomy is a reasonable second-line treatment. Autoimmune phenomena, largely related to blood cells, are based in the immune dysregulation of CLL. Longer survivals in CLL patients, more treatment regimens per patient, and more immunosuppression with modern treatments, allow us to predict an increasing incidence of autoimmune blood cell diseases in CLL.