Papers by Keyword: Nutrient Removal

Abstract: The aim of the study was to make known of the adsorption property of several materials which would be the component of a type of green sorption media blends having advantages in cost, availability, permeability, environmental benefit, and strong removal efficiency to the nutrient from surface runoff. The media blends were suitable for the substrate in the retention ponds, bio-swales, rainwater garden, river side pond, and helpful to control the non-pointed nutrient pollution in the surface runoff. The sand-loam, sawdust, tire crumb, limestone, and ceramic sand were selected to study the adsorption property of ammonia, nitrates, total phosphorus (TP) in the static adsorption test. Langmuir and Freundlich isotherm were used to fit the adsorption property. The experimental results showed that it was the combined action of physical and chemical adsorption to the removal of ammonia, nitrate, TP by the five kinds of adsorption materials. The adsorption property to the ammonia of the five materials were sand-loam>sawdust>ceramic sand>limestone>tire crumb, to the nitrate were sand-loam>tire crumb>sawdust>ceramic sand>limestone, to the TP were tire crumb>sand-loam>ceramic sand> limestone>sawdust. The sand-loam and sawdust were the prior materials to remove nitrogen, while the tire crumb had the great advantages to remove phosphorus.

Abstract: Bioretention media composition plays an important role in maintaining hydraulic conductivity within appropriate range and treating stormwater runoff to reduce pollution to receiving water bodies. This study investigated 4 types of bioretention media, 2 of which different types of compost and another 2 using shredded newspaper and crushed cockle shell as additives to modify the bioretention media. The objective of the study was to provide insight on hydraulic performance and media characteristics that control bioretention stormwater treatment performance. Results showed that organic matter content has no effect on hydraulic conductivity and nutrient removal performance of the media. Comparison of hydraulic conductivity and nutrient removal showed that reduced hydraulic conductivity (from 250mm/hr to 159mm/hr) increased total suspended solids (TSS) removal of the media (up to 98.5%) but has no effect on total nitrogen (TN) and total phosphorus (TP). The preliminary pollutant test using natural runoff showed that bioretention media enhanced with 10% shredded newspaper performed the best in TN removal (up to 85.3%) and bioretention media enhanced with 10% crushed cockle shell removed the most TP (up to 95.6%).

Abstract: The study examines the efficiency of nutrients removal by a locally isolatedmicroalgae strain from Palm Oil Mill Effluent (POME) treatment pond, Characium sp. Theexperiment was conducted in laboratory conditions at room temperature for 20 days. Sampleswere taken at a two-day interval for dry weight, Chemical Oxygen Demand (COD), andnutrient removal analysis as well as carotenoid, protein and lipid content. The study showedthat the COD level of POME was reduced by 45.41%. Characium sp successfully removed90.35% of ammoniacal nitrogen, 86.9% of ammonia, 87% of ammonium and 88.6% of totalnitrogen content. This species was also found to remove up to 99.1% of phosphate contentand 99.5% of phosphorus. Characium sp produced 0.78 mg/L of carotenoid, 15.24 mg/L ofprotein and 18.43 mg/L of lipid by the end of the 20-day study period.

Abstract: The flashboard was installed in the circulation compartment of the modified oxidation ditch in order to regulate the mixed reflux from aerobic zone to anoxic zone. The differences of the nutrient removal efficiencies and the phosphate-removal bacteria content were researched before and after flashboard installation. The results showed that the average removal efficiencies of COD, NH₄⁺, TN, TP were 93.3%, 87.1%, 78.1% and 96.0% respectively, and the proportion of denitrifying phosphate-removal bacteria (DPB) to total phosphorus accumulating organisms were 46.1% after the flashboard installation. However, the average removal efficiencies of COD, NH₄⁺, TN, TP were 91.2%, 82.7%, 67.2% and 86.4% respectively, and the proportion of denitrifying phosphate-removal bacteria to total phosphorus accumulating organisms were 17.54% before the flashboard installation. So, the modified oxidation ditch with flashboard could enrich denitrifying phosphate-removal bacteria and and improve the nutrient removal efficiencies.

Abstract: Ultrasonic-disintegrated sludge supernatant was supplemented into A²O system to assess the effects on nutrient removal performances and microbial community changes. In this experiment, easily biodegradable organics accounted for 50.6% of sludge supernatant, indicating its potential for biological nutrient removal. Simultaneously, during two-month operational period, the ammonia nitrogen (NH₄⁺-N) and total phosphorus (TP) removal efficiencies improved to 92.3% and 93.5% from75.6% and 53.4%. Duo to the application of sludge supernatant, two microbial phyla, Proteobacteria and Actinobacteria, were primarily responsible for the biological nutrient removal. In particular, the sludge supernatant was selective for ammonia oxidizing bacteria Comamonas sp. and denitrifying phosphate accumulating organisms Sphingobacterium.

Abstract: Electrochemical processing combined with the system of microalgae Chlorella vulgaris was used to treat the synthetic organic wastewater in this paper. The effect of wastewater concentration on the biomass growth and nutrients removal was investigated. Three levels of the wastewater concentrations were ranked as Low, Mid and High, respectively. After 2 h of electrolysis pretreatment and 10 d of microalgae cultivation, TOC, NH₄-N, and TP concentrations in the group Low were reduced by 83.7%, 99.3% and 95.0%, respectively. The Chlorella vulgaris in the groups Mid and High without electrolysis pretreatment did not survive longer than 24 h, whereas it grown well in the wastewater pretreated by electrolysis. The dry weight (DW) of Chlorella vulgaris in the group Low with electrolysis pretreatment was increased from 0.048 g/l to 1.087 g/l by 10 d cultivation. Results indicate that electrolysis pretreatment for wastewater can provide appropriate conditions for the subsequent biological treatment and efficiently promote the biomass growth of Chlorella vulgaris.

Abstract: A lab-scale hybrid constructed wetland system was constructed to purify polluted river water. The system was composed of a first stage of the vertical subsurface flow filter, followed by a second stage of horizontal subsurface flow bed. Both beds used furnace slag with a size of 4-60 mm for the main layer. The system was continuously fed. Different depths of unsaturated layer (0 cm, 15 cm and 30 cm) in vertical filter were tested. The unsaturated layer of 30 cm in vertical filter presented the most effective ammonia removal of 89.1%, while lowest NO3--N removal rate of 74.1% for the system. High TN removal efficiencies (77.3%-81.0%) could be observed during operation of three depths. The removals of COD and TP were in the range of 97.1%-98.4% and 76.4%-88.9%, respectively.

Abstract: ECOSUNIDE (ecological superior nitrification denitrification), based on the advanced theories including uniform dynamic, dynamic loading, sludge concentraion optimization, simultaneous nitrification and denitrification, etc., is characterized by high removal efficiency of COD, BOD, nutrient, short total detention period, low operating cost, etc. This process has been successfully applied in the Further Treatment Engineering in Luozhuang of Linyi. The effluent qualities meet the ClassⅠ-A Criteria Specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).

Abstract: The main purpose of this study was to treat organic pollutants, nitrogen and phosphorus in polluted river water by the use of constructed wetland (CW) systems. A laboratory experiment research was conducted on subsurface flow constructed wetland systems operated in vertical flow (VF) and horizontal flow (HF) mode. The systems were unplanted and hydraulic retention times were identically 2.7 days. The average removal efficiencies for HFCW and VFCW were NH+ 4-N 64.9% and 75.2%, NO- 3-N 92.3% and 40.1%, COD 97.5% and 90.1%, TP 94.6% and 96.2%, respectively. The removal of NH+ 4-N and NO- 3-N in the different CW units were in order of VFCW (drained) > VFCW (flooded) > HFCW and HFCW > VFCW (flooded) > VFCW (drained), respectively. When the water level in the VFCW was changed, an obvious fluctuation of the effluent NH+ 4-N and NO- 3-N concentrations was observed.