Multi-Scale Analysis of the Dependence of Water Quality on Land Use Using Linear and Mixed Models

Land use influences water quality in streams at different spatial scales and varies in time and space. Water quality has long been associated with agricultural and urban land uses in catchments. The effects of developed, forest, pasture, and agricultural land use on nitrogen, nitrate, and nitrite (NNN); total phosphorus (TP); total suspended solids (TSS); chemical oxygen demand (COD); dissolved oxygen (DO) and total Kjeldahl nitrogen (TKN) concentrations and their sensitivity were quantified to spatial pattern differences. The linear mixed modeling framework was used to examine the importance of spatial extent on models with water quality parameters as the response variable and land use types as the predictor variable. The results indicated that land use categories on different water quality parameters were significant and dependent on the selected spatial scales. Land use exhibited a strong association with total phosphorus and total suspended solids for close reach distances. Phosphorus is not highly soluble, and it binds strongly to fine soil particles, which are transported by water via runoff. Nitrogen, nitrate, and nitrite, dissolved oxygen, chemical oxygen demand, and total Kjeldahl nitrogen concentrations were better predicted for further reach distances, such as 45 or 50 km, where the best model of nitrogen, nitrate, and nitrite is consistent with the high mobility of NO3−.

Effects of Packing Media and the Insertion of Vegetation on the Performance of Biological Trickling Filters

The use of the plant Chrysopogon zizanioides (vetiver), able to develop under adverse conditions while removing a great number of pollutants, in constructed wetlands (CWs) is widely reported. Regarding the biological trickling filters (BTFs), the selection of the media is one of the most important factors in its performance. We investigated whether the addition of vegetation improves the efficiency of the basic parameters of BTFs with gravel. In addition, due to the properties of light expanded clay aggregate (LECA), we evaluated whether the support media composed of vetiver and LECA is able to increase the media’s oxygenation. The efficiencies were 39, 49, 56, and 49% for biochemical oxygen demand (BOD) and 27, 20, 12, and 31%, for total Kjeldahl nitrogen (TKN) in BTFLV (vetiver with LECA), BTFL (LECA only), BTFGV (vetiver with gravel) and BTFG (gravel only), respectively. LECA when associated with vetiver may have provided higher aeration of the filter, denoted by the higher nitrate effluent concentration (0.35, against 0.03, 0.06, and 0.10 mg L−1 for BTFL, BTFGV, and BTFG). Vetiver had no improvement on BTFs performance concerning BOD. However, associated with LECA, its use could be viable to remove dissolved forms of nitrogen.

Alteration of Spatial Pollution Compounds to Eutrophication Phenomenon of Small-Scale Area under Corona Virus Disease Circumstances

This research aims to study the alteration of spatial pollution compounds to the eutrophication phenomenon in water resources during the COVID-19 situation. Sixteen water resources were monitored to examine the impact of spatial pollution compound on eutrophication phenomenon discovered from the activities of the Valaya Alongkorn Rajabhat University under the Royal Patronage. The analytical parameters were DO, nitrite (NO2-), nitrate (NO3-), ammonia (NH3), phosphate (PO4-), and Total kjeldahl nitrogen (TKN) collected in three months (November 2020, January 2021, and March 2021). This research has presented the differences in water resource characters in three months and the positive impact of the COVID-19 lockdown on wastewater. The total nitrogen was highest in November 2020 when compared with that of in January and March 2021 because it was a ‘normal situation’ (no lockdown) in November. The student, officer, lecturer, and government visitors came to use the facilities of the university. The results of total kjeldahl nitrogen showed a high range during the working period. The effect of P was higher on the water bodies in November than January and March because in November was a normal situation (no lockdown). The N:P ratio showed different trends to the eutrophication phenomenon with nitrogen and phosphate. Therefore, a comparison between a situation with lockdown and no lockdown showed that the lockdown situation was environment friendly. Finally, the results also confirm an improvement in environmental quality, which happened when humans were absent, especially in coronavirus circumstances.

Impact of Tetracycline on Microbial Communities in the Secondary Treatment Process of Wastewater Treatment Systems

This study examined the impact of the antibiotic tetracycline at environmentally relevant concentrations (1μg/L and 10μg/L) on the composition and function of the microbial community that are responsible for the secondary treatment step in a municipal wastewater treatment plant (MWTP). Specifically, this study examined whether nitrification is inhibited by the presence of tetracycline under high and low nutrient replacement conditions. Aerated semi-batch reactors were set up containing activated sludge samples from a MWTP. Reactors were replenished with a synthetic wastewater media at two constant replacement rates for a period of 4 weeks. Parameters such as ammonia, nitrate/nitrite and total Kjeldahl nitrogen concentrations were monitored to evaluate the nitrogen removal efficiency. Under a low nutrient replacement rate, tetracycline was observed to have a positive impact on ammonia removal and nitrification than at the higher one. However, total Kjeldahl nitrogen concentrations increased in low nutrient replacement reactors under the presence of tetracycline which suggested a potential inhibitory effect on denitrification. At high nutrient replacement rates, tetracycline did not demonstrate an inhibitory effect on both nitrification and denitrification processes. Overall, it appears that both antibiotic presence and nutrient replacement rates can influence the community composition and function of microbial communities found in a MWTP.

Impact of Tetracycline on Microbial Communities in the Secondary Treatment Process of Wastewater Treatment Systems

This study examined the impact of the antibiotic tetracycline at environmentally relevant concentrations (1μg/L and 10μg/L) on the composition and function of the microbial community that are responsible for the secondary treatment step in a municipal wastewater treatment plant (MWTP). Specifically, this study examined whether nitrification is inhibited by the presence of tetracycline under high and low nutrient replacement conditions. Aerated semi-batch reactors were set up containing activated sludge samples from a MWTP. Reactors were replenished with a synthetic wastewater media at two constant replacement rates for a period of 4 weeks. Parameters such as ammonia, nitrate/nitrite and total Kjeldahl nitrogen concentrations were monitored to evaluate the nitrogen removal efficiency. Under a low nutrient replacement rate, tetracycline was observed to have a positive impact on ammonia removal and nitrification than at the higher one. However, total Kjeldahl nitrogen concentrations increased in low nutrient replacement reactors under the presence of tetracycline which suggested a potential inhibitory effect on denitrification. At high nutrient replacement rates, tetracycline did not demonstrate an inhibitory effect on both nitrification and denitrification processes. Overall, it appears that both antibiotic presence and nutrient replacement rates can influence the community composition and function of microbial communities found in a MWTP.

Optimization of Bioslurry-Available Plant Nutrients Using T. brownii and Acanthaceae spp. Biocatalysts

The plant extracts of T. brownii and Acanthaceae spp. have been used as biocatalysts by several communities in Kenya to hasten anaerobic digestion. This study aimed at assessing the viability of these two extracts in hastening the availability of plant nutrients from bioslurry at ambient conditions. A controlled research design was followed using uncooked kitchen waste as the substrate for 28 retention days. Changes in bioslurry physicochemical properties and available plant nutrients were monitored every 7 days using wet chemistry and spectroscopic methods. The findings indicated that the two extracts significantly impacted the levels of available plant nutrients in the bioslurry compared to the control samples. T. brownii additives significantly increased the levels of lime content, total Kjeldahl nitrogen, total phosphorus, phosphoric acid, sulfur, and soluble silicic acid. On the contrary, Acanthaceae spp. additives significantly increased the levels of calcium, potassium, nitrates, total ammoniacal nitrogen, sulfates, and phosphates in the bioslurry samples. The use of these plant extracts thus reduces the time taken while increasing the concentration of available plant nutrients from bioslurry.

Nutrient Removals by Pinestraw Harvesting in Slash Pine Plantations in Florida

Pinestraw harvesting is an important industry in the southeastern United States. There is a need to understand how fertilization can be used efficiently to sustain or increase long-term pinestraw yields and avoid adverse environmental consequences. The effects of fertilization on needlefall nutrient concentrations, pinestraw yields, and nutrient removals on soils with contrasting soil nutrient sorption potential (Entisol vs. Ultisol) were compared using two midrotation slash pine plantations in North Florida. Diammonium phosphate was applied at 0, 144, 430, or 718 kg ha–1 in the spring of 2009 and 2010. Pinestraw was harvested annually in 2009–12. Needlefall mass, pinestraw yields, total Kjeldahl nitrogen concentrations in needlefall and pinestraw, and total Kjeldahl nitrogen, P, K, Ca, and Mg removals increased with fertilization. Diammonium phosphate at 718 kg ha–1 year–1 increased pinestraw yield over the control by 37 and 35 percent 2 years after the second fertilization, and by 11 percent (from 21.5 to 23.8 Mg ha–1) and 12 percent (from 25.0 to 28.1 Mg ha–1) over the 4-year control totals, at Entisol and Ultisol sites, respectively. Differences between sites were larger than fertilization response for most variables. Yields, nutrient concentrations, and removals were higher at the more fertile Ultisol than Entisol and, at both sites, higher than most reported in the literature.

Identifying the Effect of Non-Ideal Mixing on a Pre-Denitrification Activated Sludge System Performance through Model-Based Simulations

Effectiveness of a pre-denitrification activated sludge treatment system is governed by the kinetics of the biological reactions, and the hydrodynamic mixing behavior in the reactors. Achieving good mixing conditions within a reactor not only enhances the transfer of reactants but also ensures homogeneous environmental conditions throughout the vessel when required, allowing for an effective usage of the reactor’s total volume, leading to optimized, low-cost operation. In this work, a pre-denitrification activated sludge system performance with regards to the biological treatment of organic carbon and nitrogen was investigated, under two scenarios for non-ideal mixing in the anoxic reactor. The system performance is simulated based upon the Activated Sludge Model 1 model’s biological reactions, and combining two non-ideal mixing two-parameter models: CSTR with bypass and dead volume, and two CSTRs with exchange. Performance discrepancies were then identified in the presence of non-ideal mixing. The system’s performance was found to be more susceptible to the presence of a dead volume/bypass scenario compared to the two CSTRs with material exchange scenario. Under non-ideal mixing conditions, effluent concentrations of Total Kjeldahl Nitrogen, organic carbon increased marginally, while effluent concentration of nitrate increased significantly. Similarly, the waste stream concentrations of Total Kjeldahl Nitrogen and organic carbon increased significantly as a result of an increase in the concentration of the heterotrophic biomass. The outcome of this study provides an insight when troubleshooting the operation of pre-denitrification activated sludge systems for non-ideal mixing conditions.

Effect of active and passive aeration on composting of household biodegradable wastes: a decentralized approach

Purpose Present work aims at studying the influence of active (using external aerator) and passive (natural) aeration on composting of household biodegradable wastes. Methods To study the suitability of these reactors to household conditions, continuous loading was carried out for a period of 60 days. Both the reactors were loaded with cooked as well as raw vegetable and fruit waste. Physico-chemical parameters such as temperature, pH, C/N ratio, moisture content, total organic content, Total Kjeldahl Nitrogen and seed-germination parameters such as Germination Index (GI) and Root Length Index (RLI) of the mulch were analyzed at different stages of the composting process. Results Results confirmed that, although both types of aeration seem to have performed well under continuous loading, the maturation period required for actively aerated reactor was 37.30% lesser than that of naturally aerated reactor. Conclusion Active aeration found to be more suitable to household conditions as odor and fly nuisance was relatively less.