WASTEWATER DISINFECTION BY UV AT TRANI MUNICIPAL PLANT

1994 ◽  
Vol 30 (4) ◽  
pp. 125-132 ◽  
Author(s):  
D. Carnimeo ◽  
E. Contini ◽  
R. Di Marino ◽  
F. Donadio ◽  
L. Liberti ◽  
...  

The pilot investigation on the use of UV as an alternative disinfectant to NaOCI was started in 1992 at Trani (South Italy) municipal wastewater treatment plant (335 m3/h). The results collected after six months continuous operation enabled us to compare UV and NaOCl disinfection effectiveness on the basis of secondary effluent characteristics, quantify photoreactivation effects, evidence possible DBP formation and assess costs.

2018 ◽  
Vol 77 (11) ◽  
pp. 2723-2732 ◽  
Author(s):  
Xiaowei Zheng ◽  
Shenyao Zhang ◽  
Jibiao Zhang ◽  
Deying Huang ◽  
Zheng Zheng

Abstract With the improvement of wastewater discharge standards, wastewater treatment plants (WWTPs) are continually undergoing technological improvements to meet the evolving standards. In this study, a quartz sand deep bed denitrification filter (DBDF) was used to purify WWTP secondary effluent, utilizing high nitrate nitrogen concentrations and a low C/N ratio. Results show that more than 90% of nitrate nitrogen (NO3-N) and 75% of chemical oxygen demand (COD) could be removed by the 20th day of filtration. When the filter layer depth was set to 1,600 mm and the additional carbon source CH3OH was maintained at 30 mg L−1 COD (20 mg L−1 methanol), the total nitrogen (TN) and COD concentrations of DBDF effluent were stabilized below 5 and 30 mg L−1, respectively. Analysis of fluorescence revealed that DBDF had a stronger effect on the removal of dissolved organic matter (DOM), especially of aromatic protein-like substances. High throughput sequencing and qPCR results indicate a distinctly stratified microbial distribution for the main functional species in DBDF, with quartz sand providing a good environment for microbes. The phyla Proteobacteria, Bacteroidetes, and Chloroflexi were found to be the dominant species in DBDF.


2013 ◽  
Vol 9 (2) ◽  
pp. 166-173

The present study investigated tertiary physico-chemical treatment of the secondary effluent from the Chania municipal Wastewater Treatment Plant (WTP). Laboratory experiments were carried out with the aim of studying coagulation efficiency regarding reduction of turbidity, soluble COD and phosphorus both in a conventional Coagulation-Settling treatment scheme, as well as by means of Contact Filtration. The results showed that high doses of coagulants (0,5 mmol Me+3 l-1 or higher) are required to achieve significant removals of turbidity after settling. At these high doses, soluble COD can be removed by about 50%, while soluble Phosphorus by 80-95%. Ferric Chloride demonstrated slightly better removal ability as compared to Alum. The Chania WTP effluent was also treated by Contact Filtration, using a very low dose of coagulants, 0,1 mmol Me+3 l-1. Turbidity was removed by around 50%, while at this low coagulant dose removals of COD and Phosphorus were insignificant. Filtration was effective in the first 35cm of the filter bed. No significant differences were observed between the coagulants Alum and FeCl3 in the elimination of turbidity. Nevertheless, with the use of Alum a smaller filter headloss was observed, during the first two hours of continuous filtration, in comparison with the use of FeCl3 (nearly double). No difference was observed between the headloss developed at a filter depth of 5cm as compared to that developed at a depth of 70cm. This indicates that the headloss increase was due to the accumulation of suspended and colloidal solids within the first layers of the sand filter.


2021 ◽  
Vol 11 (5) ◽  
pp. 2207
Author(s):  
Diana Pacheco ◽  
A. Cristina S. Rocha ◽  
Analie Garcia ◽  
Ana Bóia ◽  
Leonel Pereira ◽  
...  

The need to reduce the costs associated with microalgae cultivation encouraged scientific research into coupling this process with wastewater treatment. Thus, the aim of this work was to assess the growth of Chlorella vulgaris (Chlorophyta) in different effluents from a municipal wastewater treatment plant (WWTP), namely secondary effluent (SE) and sludge run-off (SR). Assays were performed, under the same conditions, in triplicate with 4 dilution ratios of the wastewaters (25%, 50%, 75% and 100%) with the standard culture medium bold basal medium double nitrated (BBM2N) as a control. The capability of C. vulgaris for biomass production, chlorophyll synthesis and nutrients removal in the SE and SR was evaluated. The 25% SE and 25% SR showed increased specific growth rates (0.47 and 0.55 day−1, respectively) and higher biomass yields (8.64 × 107 and 1.95 × 107 cells/mL, respectively). Regarding the chlorophyll content, the 100% SR promoted the highest concentration of this pigment (2378 µg/L). This green microalga was also able to remove 94.8% of total phosphorus of SE, while in 50% SR, 31.2% was removed. Removal of 73.9% and 65.9% of total nitrogen in 50% and 100% SR, respectively, was also observed. C. vulgaris growth can, therefore, be maximized with the addition of municipal effluents, to optimize biomass production, while cleansing the effluents.


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