Technical Problems Ensuing From UASB Reactor Application in Domestic Wastewater Treatment without Pre-Treatment

Since mid 1999 MBR technology is introduced into domestic wastewater treatment in Germany. First wwtps went in operation performing a conventional mechanical treatment (covering screens, grit chambers and grease traps) without any advanced mechanical pre-treatment stage. After a short operation period module-clogging and hence module sludging was observed. Thus, mechanical pre-treatment was upgraded introducing sieves, first of all to reduce hairs and fibrous substances. But today knowledge is relatively poor concerning effectiveness and treatment efficiency of the whole bunch of aggregates that had been brought to market and vary e.g. in gap size and gap geometry. This paper gives the basics of sieving, the current status of mechanical pre-treatment on German municipal MBR plants and exemplifies an investigation to determine treatment efficiency of two different sieve aggregates.

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Coupling of sequencing batch reactor and UASB reactor for domestic wastewater treatment

Desalination ◽

10.1016/j.desal.2008.05.011 ◽

2009 ◽

Vol 242 (1-3) ◽

pp. 325-335 ◽

Cited By ~ 34

Author(s):

A. Moawad ◽

U.F. Mahmoud ◽

M.A. El-Khateeb ◽

E. El-Molla

Keyword(s):

Wastewater Treatment ◽

Sequencing Batch Reactor ◽

Batch Reactor ◽

Domestic Wastewater ◽

Uasb Reactor ◽

Domestic Wastewater Treatment

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Evaluating the sustainability of waste substrates for microalgal biomass production using different modes of cultivation

10.51415/10321/3102 ◽

2018 ◽

Author(s):

◽

Prathana Ramsundar

Keyword(s):

Wastewater Treatment ◽

Biomass Production ◽

Bacterial Load ◽

Biomass Productivity ◽

Domestic Wastewater ◽

Microalgal Biomass ◽

Domestic Wastewater Treatment ◽

Cultivation Strategy ◽

Production Strategy ◽

Pre Treatment

The utilization of wastewater as a substrate for microalgal biomass cultivation is one of the few potentially viable routes for fuel and feed applications. In this study, the suitability of various liquid wastewater streams and waste biosolids from a domestic wastewater treatment plant was assessed for microalgal cultivation. The wastewater substrates were analyzed for nutrient content as a potential growth medium. For liquid waste substrates, physical, thermal and biological pre-treatment methods were evaluated to minimize the bacterial load. Biomass, physiology, nutrient removal efficiencies and biochemical constituents of Chlorella sorokiniana were investigated in influent (INF) and anaerobic tank centrate (AC) under mixotrophic (Mixo) and heterotrophic (Hetero) cultivation modes. Mixotrophic cultivation conditions demonstrated efficient ammonium (94.29%) and phosphate (83.30%) removal with promising biomass (77.14 mgL-1d-1), lipid (24.91 mgL-1d-1), protein (22.36 mgL-1d-1) and carbohydrate (20.10 mgL-1d-1) productivities. Urea supplementation (1500 mgL-1) further enhanced biomass (162.50 mgL-1d-1), lipid (24.91 mgL-1d-1), protein (22.36 mgL-1d-1) and carbohydrate (20.10 mgL-1d-1) productivities in Mixo AC. Therefore, the urea supplemented Mixo AC approach for microalgal cultivation was developed as a suitable biomass production strategy. This work also elucidated a novel algae cultivation strategy for utilisation of waste biosolids, where nutrient-rich waste activated sludge (WAS) and final effluent (FE) from the wastewater treatment process was used for microalgal biomass generation. This strategy reduced the use of synthetic nutrients, fertilizers and freshwater which contribute significantly towards the overall cost of biomass production. Strategy development included the investigation of physical, thermal and chemical pre-treatment methods to assist in effective nutrient release and bacterial load reduction. Evaluation of growth kinetics, photosynthetic performance, nutrient removal efficiencies and biochemical composition of microalgae under mixotrophic and heterotrophic modes of cultivation were performed. Furthermore, urea supplementation was studied to improve biomass productivity. Microalgae cultivation in acid pre-treated (pH 2) WAS + FE with urea supplementation (1500 mgL-1) showed enhanced biomass productivity of 298.75 mgL-1d-1. Microalgal biomass grown with WAS + FE using the developed strategy exhibited greater lipid (72.95 mgL-1d-1) and protein (72.84 mgL-1d-1) productivities and comparable carbohydrate yields (73.07 mgL-1d-1) to that of synthetic media. Thus mixotrophic mode of cultivation coupled with urea supplementation to WAS + FE proved to be a suitable cultivation strategy for C. sorokiniana. The study developed an efficient strategy to utilize AC and WAS + FE as a growth medium for microalgae. Furthermore, findings from this study have demonstrated the potential of waste streams and waste solids from domestic wastewater treatment plants for microalgal biomass generation

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Sewage Treatment by UASB-Reactor. Operation Results and Recommendations for Design and Utilization

Water Science & Technology ◽

10.2166/wst.1992.0147 ◽

1992 ◽

Vol 25 (7) ◽

pp. 143-157 ◽

Cited By ~ 17

Author(s):

S. M. M. Vieira ◽

A. D. Garcia

Keyword(s):

Wastewater Treatment ◽

Technology Development ◽

Sewage Treatment ◽

Domestic Wastewater ◽

Uasb Reactor ◽

First Year ◽

Second Phase ◽

Treatment Processes ◽

Domestic Wastewater Treatment ◽

Operation Results

A 120 m3 UASB reactor for domestic wastewater treatment was designed and built, based upon results obtained through the operation of a 106 L pilot unit. This system was operated for four years for demonstration and technology development purposes. The results obtained in the first year of operation were already previously presented. After this period, some modifications were carried out aiming at design and operation and maintenance and facilities improvement. This was followed by a continuous 2-year operating period. In this work are presented some of the results obtained in this second phase of operation, with hydraulic retention times ranging from 5 to 15 h, resulting in an effluent with 50 to 150 mg COD.L−1 and 40 to 85 mg BOD.L−1. Some criteria are presented, together with the experience acquired in the development of this technology from the pilot reactor phase. During this period, several lectures and discussions about the system were held in relation to its use, operation and efficiency, leading to considerations about the advantages and convenience of this choice, by establishing a comparison between it and other wastewater treatment processes.

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