Mixed cultivation as an effective approach to enhance microalgal biomass and triacylglycerol production in domestic secondary effluent

Rainfall diminution in the last years has entailed water scarcity in plenty of European regions, especially in Mediterranean areas. As a consequence, regional water authorities have enhanced wastewater reclamation and reuse. Thus, the implementation of tertiary treatments has become of paramount importance in the municipal wastewater treatment plants (WWTP) of Valencian Region (Spain). Conventional tertiary treatments consist of a physico-chemical treatment of the secondary effluent followed by sand filtration and UV radiation. However, the addition of coagulants and flocculants sometimes does not contribute significantly in the final water quality. In this work, results of 20-months operation of three WWTP in Valencian Region with different tertiary treatments (two without chemicals addition and another with chemicals addition) are discussed. Besides, experiments with a 2 m3/h pilot plant located in the WWTP Quart-Benager in Valencia were performed in order to evaluate with the same secondary effluent the effect of the chemicals addition on the final water quality. Results showed that the addition of chemicals did not improve the final water quality significantly. These results were observed both comparing the three full scale plants and in the pilot plant operation.

Download Full-text

Ozonation of a secondary effluent both for fresh water protection and re-use

Water Practice & Technology ◽

10.2166/wpt.2006039 ◽

2006 ◽

Vol 1 (2) ◽

Cited By ~ 1

Author(s):

M. Antonelli

Keyword(s):

Fresh Water ◽

Secondary Effluent ◽

Water Protection

Download Full-text

Viruses and Water: Problems, Detection, and Control

Water Science & Technology ◽

10.2166/wst.1993.0543 ◽

1993 ◽

Vol 27 (7-8) ◽

pp. 127-133 ◽

Cited By ~ 2

Author(s):

H. Dizer ◽

J. Dürkop ◽

A. Grohmann ◽

H. Kopecka ◽

J. M. López-Pila

Keyword(s):

Drinking Water ◽

Surface Waters ◽

Membrane Filtration ◽

Wastewater Treatment Plants ◽

Health Hazard ◽

Primary Source ◽

Detection Methods ◽

Secondary Effluent ◽

Naturally Occurring ◽

Water Problems

Secondary effluent of wastewater treatment plants contains a high number of viruses and other pathogens, which pose a health risk to the population, (especially when receiv ng waters are used for bathing and swimming, or for growing shellfish. In areas with a high density of population, where drinking water supply is dependent on surface waters and contaminated rivers are the primary source of drinking water, failure of the filtration or of the disinfection step, or of any other “barriers” supposed to warrant safe potable water, will increase the risk of health hazard for the consumer. We have compared the efficiency of viral elimination in secondary effluent by flocculation, uv rradiation and membrane filtration taking naturally occurring, or additionally seeded f2 phages, as indicator for viruses. Flocculation decreased the number of phages present in secondary effluent by more than two logs. If combined with uv irradiation, the elimination reached five additional logs. Membrane filtration eliminated essentially all naturally occurring phages. Improvement of the quality of surface waters calls for a refinement of detection methods for viruses. We have found that the polymerase chain reaction (PCR) might be used for detecting viruses in surface waters.

Download Full-text

WASTEWATER DISINFECTION BY UV AT TRANI MUNICIPAL PLANT

Water Science & Technology ◽

10.2166/wst.1994.0173 ◽

1994 ◽

Vol 30 (4) ◽

pp. 125-132 ◽

Cited By ~ 2

Author(s):

D. Carnimeo ◽

E. Contini ◽

R. Di Marino ◽

F. Donadio ◽

L. Liberti ◽

...

Keyword(s):

Wastewater Treatment ◽

Municipal Wastewater ◽

Treatment Plant ◽

Continuous Operation ◽

Secondary Effluent ◽

Municipal Wastewater Treatment ◽

South Italy ◽

Wastewater Disinfection ◽

Pilot Investigation ◽

Effluent Characteristics

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.

Download Full-text

Increasing the capacity of an extended nutrient removal plant by using different techniques

Water Science & Technology ◽

10.2166/wst.1998.0355 ◽

1998 ◽

Vol 37 (9) ◽

pp. 175-183 ◽

Cited By ~ 3

Author(s):

B. Andersson ◽

H. Aspegren ◽

U. Nyberg ◽

J. la Cour Jansen ◽

H. Ødegaard

Keyword(s):

Nitrogen Concentration ◽

Treatment Plant ◽

Appropriate Technology ◽

Secondary Effluent ◽

Suggested Approach ◽

Future Design ◽

Actual Load ◽

Full Scale Tests ◽

Plant Capacity ◽

Treatment Step

A comprehensive investigation which included full scale tests was initiated towards the late 1980:s with the primary aim to find an appropriate technology for the Klagshamn wastewater treatment plant in Malmö, Sweden. The finally selected strategy enabled that a concentration of less than 8 mg N/l could be reached in the secondary effluent without having to extend either the primary or secondary treatment step at the actual load on the plant. In order to comply with a future stringent phosphorus standard however, a tertiary filtration plant has to be built. In future, it has to be anticipated that the load on the plant may be doubled due to the fact that a bridge between Malmö and Copenhagen is being built. As a consequence, it was important to continue the upgrading work by estimating the ultimate plant capacity and to look for measures to increase the capacity if necessary. By optimising the plant operation, it seems possible to reach an effluent nitrogen concentration of less than 12 mg/l at a load corresponding to the future design load. The suggested approach implies that the plant has to be operated on the margin and as a consequence the possibility to include a denitrification step as part of the filtration plant was also investigated. As a result, it was decided to build a separate denitrification step at the same time as the filtration plant was built.

Download Full-text

Textile Wastewater Reuse: Ozonation of Membrane Concentrated Secondary Effluent

Water Science & Technology ◽

10.2166/wst.1999.0580 ◽

1999 ◽

Vol 40 (4-5) ◽

pp. 99-105 ◽

Cited By ~ 18

Author(s):

A. Lopez ◽

G. Ricco ◽

R. Ciannarella ◽

A. Rozzi ◽

A. C. Di Pinto ◽

...

Keyword(s):

Wastewater Treatment ◽

Acute Toxicity ◽

Wastewater Treatment Plant ◽

Textile Industry ◽

Nonionic Surfactants ◽

Wastewater Reuse ◽

Treatment Plant ◽

Textile Wastewater ◽

Secondary Effluent ◽

Complete Disappearance

Among the activities appointed by the EC research-project “Integrated water recycling and emission abatement in the textile industry” (Contract: ENV4-CT95-0064), the effectiveness of ozone for improving the biotreatability of recalcitrant effluents as well as for removing from them toxic and/or inhibitory pollutants has been evaluated at lab-scale. Real membrane concentrates (pH=7.9; TOC=190 ppm; CDO=595 ppm; BOD5=0 ppm; Conductivity=5,000 μS/cm; Microtox-EC20=34%) produced at Bulgarograsso (Italy) Wastewater Treatment Plant by nanofiltering biologically treated secondary textile effluents, have been treated with ozonated air (O3conc.=12 ppm) over 120 min. The results have indicated that during ozonation, BOD5 increases from 0 to 75 ppm, whereas COD and TOC both decrease by about 50% and 30 % respectively. As for potentially toxic and/or inhibitory pollutants such as dyes, nonionic surfactants and halogenated organics, all measured as sum parameters, removals higher than 90% were achieved as confirmed by the complete disappearance of acute toxicity in the treated streams. The only ozonation byproducts searched for and found were aldehydes whose total amount continuously increased in the first hour from 1.2 up to 11.8 ppm. Among them, formaldehyde, acetaldehyde, glyoxal, propionaldehyde, and butyraldehyde were identified by HPLC.

Download Full-text