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Secondary Treatment
Published in David H.F. Liu, Béla G. Lipták, Wastewater Treatment, 2020
In designing an aerated lagoon, environmental engineers must incorporate the following parameters: (1) BOD removal, (2) effluent characteristics, (3) temperature effects, and (4) oxygen requirements. The design basis for a lagoon can be the mean cell residence time since the aerated lagoon is a completely mixed reactor without recycling. Selected mean cell residence time should ensure that the suspended biomass has good settlement properties, and be high enough to prevent cell wash-out. Typical design mean cell residence time for lagoons treating domestic waste varies from 3 to 6 days.
Biological Oxidation: Lagoons
Published in Gaetano Joseph Celenza, Industrial Waste Treatment Process Engineering, 2019
An aerated lagoon can be used to treat industrial wastes containing dissolved organics and relatively low nondegradable solids content. Low nondegradable influent solids are essential because they will add to the effluent suspended solids concentration, impacting effluent quality. The area dimensions of a lagoon are not generally critical, configured to appropriate dimensions to fit available land area. Depths can range from 2 to 6 m (6 to 20 ft), governed by required retention times, selected surface area, and the aeration device limits.
Performance of real-scale anaerobic baffled reactor-swim bed tank system in treating fishmeal wastewater
Published in Journal of Environmental Science and Health, Part A, 2020
Alqadri Asri Putra, Takahiro Watari, Masashi Hatamoto, Toshihiko Konda, Kenji Matsuzaki, Tan Hendra Kurniawan, Takashi Yamaguchi
The marine industry, which is the most critical economic sector in Southeast Asia,[1] has recently contributed to water pollution. This wastewater is known for its high concentration of chemical oxygen demand (COD; >10 g COD·L−1) and nitrogen compounds (0.5 to 2 g N·L−1).[2,3] As this wastewater contains high insoluble content, treating it using conventional treatment systems, such as air flotation, activated sludge, trickling filter, and aerated lagoon, is much challenging. Furthermore, conditioning this wastewater to a treatable state requires energy, land, and management of byproducts, such as excessive sludge.[4,5] In the case of Indonesia, most of these industries release untreated wastewater directly to waterbodies,[6] thereby negatively impacting environmental sustainability. The other reason why biological treatment does not appeal to local industries is the challenge of continuous feed. The fishmeal industry in Indonesia commonly operates based on seasonal harvests by local fishers. As the availability of fish as raw material cannot be assured, the intensity of the wastewater treatment process is also unpredictable. Hence, a new approach for biological treatment needs to be considered.
Pistia stratiotes in the phytoremediation and post-treatment of domestic sewage
Published in International Journal of Phytoremediation, 2019
Daniel Schwantes, Affonso Celso Gonçalves, Andréia da Paz Schiller, Jéssica Manfrin, Marcelo Angelo Campagnolo, Eduardo Somavilla
The most used processes to treat domestic effluents in tropical countries are: preliminary treatment, secondary treatment (with the previous correction of pH and artificial addition of nutrients, using anaerobic reactor of ascending flow—UASB—or other anaerobic reactors), activated sludge, biological filtration, ponds stabilization and post-treatment in aerated lagoon, followed by sedimentation (Sperling 1996a,b).