Optimization of Nutrient Removal in Stockholm

Brattberg, G.; Reinius, L.-G.; Tendaj, M.

doi:10.2166/wst.1991.0191

Cited by 3 publications

(2 citation statements)

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“…2a). Similarly, improved P removal in an STP reduced Chl a concentrations and cyanobacterial abundance in Stockholm's inner archipelago, which receives large freshwater inputs from Lake Mä laren (Brattberg et al 1991). In the current study, the marked decrease in pigment concentrations after the mid-1990s (Fig.…”

Section: Discussionmentioning

confidence: 99%

Effects of land use, urbanization, and climate variability on coastal eutrophication in the Baltic Sea

Savage

Leavitt

Elmgren

2010

Limnology & Oceanography

104

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Sedimentary records of organic matter inputs (stable nitrogen isotopes [d 15 N], nitrogen [N], and carbon [C] content), phytoplankton abundance (pigments, stable carbon isotopes [d 13 C]), and community composition (pigments) were used to reconstruct the history and pathway to water-quality degradation in a Swedish Baltic coastal bay. Changes in nutrient sources and cycling began in the 1800s, but eutrophication intensified only after the 1950s, coincident with intensified agricultural practices. Specifically, sedimentary N and C content doubled, d 13 C increased, and concentrations of pigments indicative of total algal biomass (b-carotene, Chlorophyll a), diatoms (fucoxanthin, diatoxanthin), chlorophytes (lutein-zeaxanthin, Chlorophyll b), and cyanobacteria (canthaxanthin) increased significantly after 1950. Enhanced algal abundance was most strongly related to total N influx and secondly to total P influx. In particular, historical change in algae was related to agricultural N influx and only weakly to agricultural P. In recent decades, wastewater N influx has further stimulated algal biomass, particularly diatoms. In contrast, colonial cyanobacteria were more correlated to total P than total N inputs. Variance-partitioning analysis explained 60% of the changes in algal abundance and community composition since 1880, with diffuse and point nutrients jointly explaining 36% of the long-term change in algal biomass. Climate variability has become more important as a factor influencing coastal eutrophication in recent decades, explaining 14% of the variance in the algal data since 1975. Both urban and agricultural sources of nutrients have degraded water quality, illustrating the need for cooperation between stakeholders at regional levels to achieve ''good ecological status'' in the Baltic coastal environment.

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Section: Discussionmentioning

confidence: 99%

Effects of land use, urbanization, and climate variability on coastal eutrophication in the Baltic Sea

Savage

Leavitt

Elmgren

2010

Limnology & Oceanography

104

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“…Effluent limits for total nitrogen and total phosphorus of less than 8 mg/L and less than 0.5 mg/L, respectively, were used for design. Brattberg et al 176 discussed preliminary projects to upgrade nitrogen and phosphorus removal at various treatment plants in Stockholm. Based on 10 years of experience with biological nutrient removal systems, Pitman177 made recommendations for properly designing such processes.…”

Section: Wastewater Treatmentmentioning

confidence: 99%

Activated sludge

Aitken¹,

Heck²,

Mines³

et al. 1992

Water Environment Research

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PROCESS MODELING AND KINETICSMechanistic approaches. A procedure was developed to obtain stoichiometric and kinetic parameters for heterotrophic growth and hydrolysis of slowly degradable organic matter in the activated sludge process. I The procedure was based on oxygen-uptake measurements to distinguish between organic fractions in domestic wastewater. The influence ofparticle size on biological treatability of particulate matter and on treatment process kinetics was investigated," Pretreatment to modify particle-size distribution was discussed in relation to its effect on process performance. Hydrolysis of particulate organic substrate was found to be highly influenced by the electron donor available. 3 Using raw municipal wastewater as a substrate, the hydrolysis rate was high under aerobic conditions, medium under anaerobic conditions, and low under anoxic conditions. Hydrolysis ofa( 1-4) glucan bonds in macromolecular carbohydrates found in municipal wastewater was seen to be controlled by concentrations ofoxygen and/or alternate electron acceptors and was suppressed in the presence of high concentrations of soluble substrate." The extracellular enzymes responsible for carbohydrate hydrolysis were associated with the particulate fraction. Under denitrifying conditions, slowly biodegradable chemical oxygen demand (COD) was hydrolyzed more rapidly in biological phosphorusremoval systems incorporating nitrification and denitrification than in conventional nitrification/denitrification systems." The increased rate of hydrolysis in the biological phosphorus-removal system was proposed to result from the presence ofan anaerobic reactor. Measurement of dehydrogenase activity indicated that activated sludge microorganisms metabolized adsorbed substrate in the absence of significant oxygen uptake."Sykes" formulated a product-maintenance model of the activated sludge process. A cited advantage to this approach was that empirical observations were described better than with conventional kinetic models. Formation of soluble microbial products in batch reactors was studied using radiolabeled phenol and glucose." Zero-and first-order kinetic expressions adequately described the disappearance ofinitial substrate and net formation of soluble microbial products. For organisms subjected to anaerobic conditions before substrate and oxygen supply in batch systems, the observed biomass yield decreased as initial substrate to biomass concentration (So/X o) increased." A proposed explanation for this phenomenon was that the organisms needed to rebuild energy reserves at the expense of growth. In a study using synthetic wastewater, the existence ofsynchronized cell division was reported to occur in laboratory-activated sludge systems. 10 Synchronization was related to starvation ofthe organisms under anaerobic conditions in batch culture and occurred at So/X o greater than two. A model was proposed to describe the rate and extent of cometabolic transformation of halogenated aliphatic compounds by resting microbial cells.II The mod...

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Effects of Load Reductions on Phosphorus Concentrations in a Baltic Estuary—Long-Term Changes, Seasonal Variation, and Management Implications

Walve

Sandberg

Elmgren

et al. 2020

Estuaries and Coasts

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Nutrient concentrations in coastal waters are influenced not only by land runoff, point sources, and water exchange with the sea but are also modified by settlement to and release from sediments. This complicates evaluation of measures to reduce nutrient loads. We used a mass-balance box model to calculate long-term (1968–2015) and seasonal source contributions to phosphorus (P) concentrations and cycling in the stratified Stockholm inner archipelago (IA), Baltic Sea. A drastic reduction of sewage P loads in the early 1970s reduced sewage from the major to a minor P source. Further P load reductions in the 1990s cut the direct contribution from the sewage point sources to the annual mean surface water P concentration from 10 μg l−1 (25%) to < 4 μg l−1 (12%). The largest contributions to the surface water P concentration are now (from 1996) inflowing seawater (37%), freshwater (25%), and P recycling from sediments below 20 m depth (26%). Variations in freshwater flushing give higher P concentrations in dry years, when dilution of P inputs from sediments and sewage is small, while in wet years, these inputs are greatly diluted. Source-partitioned phosphate uptake shows that the spring bloom is fueled mainly by P of seawater and freshwater origin, while the contribution from sewage point sources is minor. Since sediment P release is mostly recycled P from the settled spring bloom, the P inputs from seawater and freshwater are now the major drivers of the IA P cycle. Recycling of P from sediments boosts surface water P concentrations in autumn and winter, affecting management target concentrations.

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Optimization of Nutrient Removal in Stockholm

Cited by 3 publications

References 0 publications

Effects of land use, urbanization, and climate variability on coastal eutrophication in the Baltic Sea

Effects of land use, urbanization, and climate variability on coastal eutrophication in the Baltic Sea

Activated sludge

Effects of Load Reductions on Phosphorus Concentrations in a Baltic Estuary—Long-Term Changes, Seasonal Variation, and Management Implications

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