| Abstract | AIT raw sewage was used as the raw wastewater which was discharged to 5. 08 cm W x 5.08 cm D x 61 cm L PVC tube clarifier. The effects of angles
(30°-60°), cross-sectional flow rate (4.65-13.95 m3/m2-h), initial total solids and settleable solids concentration on the tube settler performance were studied. Also the formula developed by YAO (1970), HERNANDEZ and WRIGHT
(1970) were used for studying the effect of critical falling velocity and cross-sectional flow rate. The results show that the tube clarifier can be operated at the cross-sectional flow rate 4.65 m3/m2-h with 7.9 min detention time.
The effluent total solids concentration less than 100 mg/l, effluent settleable solids 2 ml/l can be achieved at any angle (30°-60°). It was found
that the performance of tube settler decreases as the critical falling velocity or angle increases. AIT sewage combined with synthetic waste was used as the raw waste for three 5.08 cm W x 5.08 cm D x 61 cm L tubes in parallel clarifier. The parameters studied were effect of mixed liquor suspended solids (MLSS), chemical oxygen demand (COD), sludge volume index (SVI), flow rate on the performance of tube clarifier assembled at 60° inclined angle which handle the effluent
MLSS from the aeration tank. Detention time in reactor varied 4h, 6h, 8h, and 10h with initial MLSS of 2,000 mg/l, 3,000 mg/l, 4,000 mg/l and 5,000 mg/l
with an approximate organic loading of 0.055 g BOD5/g MLSS/day. It was found
that the performance of tube clarifier with 8h detention time in reactor with 50% recirculation provides better result compared to other three.
The experiment was done at the cross-sectional flow rate 1.55-5.27 m3/m2 -h. It was found that the results in term of effluent quality is poor at various sludge volume index value. The sludge volume index does not affect the
performance of tube settler at the cross-sectional flow rate 1.55-3.24 m3/m2-h but plays important role when the cross-sectional flow rate increased to 4.05 m3/m2-h. Since the fluctuations of initial MLSS concentration and also the
significance of SVI which depends on the cross-sectional flow rate, it was un
successful to utilize the design_,_ parameter V2R proposed by HERNANDEZ and WRIGHT
(1970). |