scholarly journals Nutrient recovery from swine waste and protein biomass production using duckweed ponds (Landoltia punctata): Southern Brazil

2012 ◽  
Vol 65 (11) ◽  
pp. 2042-2048 ◽  
Author(s):  
R. A. Mohedano ◽  
V. F. Velho ◽  
R. H. R. Costa ◽  
S. M. Hofmann ◽  
P. Belli Filho
Keyword(s):  
Developing Countries ◽  
Biomass Production ◽  
Removal Rate ◽  
High Protein ◽  
High Rate ◽  
Phosphorus Compounds ◽  
Pig Manure ◽  
Swine Waste ◽  
Nitrogen And Phosphorus ◽  
Duckweed Pond

Brazil is one of the most important countries in pork production worldwide, ranking third. This activity has an important role in the national economic scenario. However, the fast growth of this activity has caused major environmental impacts, especially in developing countries. The large amount of nitrogen and phosphorus compounds found in pig manure has caused ecological imbalances, with eutrophication of major river basins in the producing regions. Moreover, much of the pig production in developing countries occurs on small farms, and therefore causes diffuse pollution. Therefore, duckweed pond have been successfully used in the swine waste polishing, generating further a biomass with high protein content. The present study evaluated the efficiency of two full scale duckweed ponds for the polishing of a small pig farm effluent, biomass yield and crude protein (CP) content. Duckweed pond series received the effluent from a biodigester-storage pond, with a flow rate of 1 m3/day (chemical oxygen demand rate = 186 kg/ha day) produced by 300 animals. After 1 year a great improvement of effluent quality was observed, with removal of 96% of total Kjeldahl nitrogen (TKN) and 89% of total phosphorus (TP), on average. Nitrogen removal rate is one of the highest ever found (4.4 g TKN/m2 day). Also, the dissolved oxygen rose from 0.0 to 3.0 mg/L. The two ponds produced together over 13 tons of fresh biomass (90.5% moisture), with 35% of CP content, which represents a productivity of 24 tonsCP/ha year. Due to the high rate of nutrient removal, and also the high protein biomass production, duckweed ponds revealed, under the presented conditions, a great potential for the polishing and valorization of swine waste. Nevertheless, this technology should be better exploited to improve the sustainability of small pig farms in order to minimize the impacts of this activity on the environment.

Effects of operation parameters on nutrient removal from wastewater and high-protein biomass production in a duckweed-based (Lemma aequinoctialis) pilot-scale system

2014 ◽  
Vol 70 (7) ◽  
pp. 1195-1204 ◽  
Author(s):  
Yonggui Zhao ◽  
Yang Fang ◽  
Yanling Jin ◽  
Jun Huang ◽  
Shu Bao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Biomass Production ◽  
Water Depth ◽  
Nutrient Removal ◽  
Removal Rate ◽  
Pilot Scale ◽  
Coverage Rate ◽  
High Protein ◽  
Dianchi Lake ◽  
Operation Conditions

The effects of water depth, coverage rate and harvest regime on nutrient removal from wastewater and high-protein biomass production were assessed in a duckweed-based (Lemna aequinoctialis) pilot-scale wastewater treatment system (10 basins × 12 m2) that is located near Dianchi Lake in China. The results indicated that a water depth of 50 cm, a coverage rate of 150% and a harvest regime of 4 days were preferable conditions, under which excellent records of high-protein duckweed (dry matter production of 6.65 g/m2/d with crude protein content of 36.16% and phosphorus content of 1.46%) were obtained at a temperature of 12–21 °C. At the same time, the system achieved a removal efficiency of 66.16, 23.1, 48.3 and 76.52% for NH4+-N, TN, TP and turbidity, respectively, with the considerable removal rate of 0.465 g/m2/d for TN and 0.134 g/m2/d for TP at a hydraulic retention time of 6 days. In additionally, it was found that a lower duckweed density could lead to higher dissolved oxygen in the water and then a higher removal percentage of NH4+-N by nitrobacteria. This study obtains the preferable operation conditions for wastewater treatment and high-protein biomass production in a duckweed-based pilot-scale system, supplying an important reference for further large-scale applications of duckweed.

Soil carbon, nitrogen and phosphorus contents in maize plots after 14 years of pig slurry applications

1997 ◽  
Vol 129 (2) ◽  
pp. 187-191 ◽  
Author(s):  
J. A. HOUNTIN ◽  
D. COUILLARD ◽  
A. KARAM
Keyword(s):  
Soil Depth ◽  
Application Rate ◽  
High Rate ◽  
Total Carbon ◽  
Pig Manure ◽  
Pig Slurry ◽  
Nitrogen And Phosphorus ◽  
Total N ◽  
Extractable P ◽  
Silty Loam

Excessive applications of liquid pig manure (LPM) could result in nutrient accumulation in the soil, thereby increasing the potential for plant nutrient losses through movement in groundwater. The objective of this work was to measure the concentrations of total carbon (Ct), total nitrogen (Nt), total phosphorus (Pt) and Mehlich-3 extractable-P (PM3) with depth in a Le Bras silty loam soil growing maize (Zea maize L.) under reduced tillage conditions. The soil was fertilized annually with various rates of LPM (0, 30, 60, 90 and 120 m3/ha) in four completely randomized blocks since 1979. In autumn 1992, twenty soil plots were sampled in increments of 20 cm to a depth of 1·0 m and analysed for total C, total N, total P and Mehlich-3 extractable-P. LPM application rate (R), soil depth (D) and the interaction R × D had highly significant (P<0·001) linear effects on Ct, Nt, Pt and PM3 concentrations throughout the 100-cm depth profiles. At all depths, Ct, Nt, Pt and PM3 contents increased with increasing rates of LPM application. The zone of maximum accumulation of Ct, Nt, Pt and PM3 concentrations occurred at the first 0–40 cm depth. A significant relationship was found between soil organic matter and Nt, Pt and PM3. Differences in N and P concentrations between manure rates are due to manure and maize. The increase in PM3 was generally greater for soil samples with high Pt content. Results from this study indicate that long-term application of a high rate of LPM leads to greater total C, N and P concentrations in the soil profile.

High rate and compact single sludge pre-denitrification process for retrofit

1994 ◽  
Vol 30 (6) ◽  
pp. 31-40 ◽  
Author(s):  
Hiroyshi Emori ◽  
Hiroki Nakamura ◽  
Tatsuo Sumino ◽  
Tadashi Takeshima ◽  
Katsuzo Motegi ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
High Rate ◽  
Activated Sludge Process ◽  
Nitrogen And Phosphorus ◽  
Conventional Activated Sludge ◽  
Treatment Techniques ◽  
Conventional Activated Sludge Process ◽  
Denitrification Process

For the sewage treatment plants near rivers and closed water bodies in urbanized areas in Japan and European countries, there is a growing demand for introduction of advanced treatment processes for nitrogen and phosphorus from the viewpoints of water quality conservation and environmental protection. In order to remove nitrogen by the conventional biological treatment techniques, it is necessary to make a substantial expansion of the facility as compared with the conventional activated sludge process. In such urbanized districts, it is difficult to secure a site and much capital is required to expand the existing treatment plant. To solve these problems, a compact single sludge pre-denitrification process using immobilized nitrifiers was developed. Dosing the pellets, which are suitable for nitrifiers growth and physically durable, into the nitrification tank of single sludge pre-denitrification process made it possible to perform simultaneous removal of BOD and nitrogen in a retention time equal to that in the conventional activated sludge process even at the low water temperature of about 10 °C. The 3,000 m3/d full-scale conventional activated sludge plant was retrofitted and has been successfully operated.

Nitrogen and Phosphorus Dual-doped Porous Carbons for High-Rate Potassium Ion Batteries

Carbon ◽  
2021 ◽  
Author(s):  
Xiaoqing Ma ◽  
Nan Xiao ◽  
Jian Xiao ◽  
Xuedan Song ◽  
Hongda Guo ◽  
...  
Keyword(s):  
Potassium Ion ◽  
High Rate ◽  
Porous Carbons ◽  
Nitrogen And Phosphorus

scholarly journals Midwives and Maternal Mortality Evidence from a Midwifery Policy Experiment in 19th Century Sweden

2021 ◽  
Author(s):  
Louise Lorentzon ◽  
Per Pettersson-Lidbom
Keyword(s):  
Developing Countries ◽  
Infant Mortality ◽  
Maternal Mortality ◽  
19Th Century ◽  
Causal Effect ◽  
High Rate ◽  
Current Debate ◽  
Effective Strategy ◽  
Policy Experiment ◽  
Exogenous Source

Abstract This paper estimates the causal effect of a historical midwifery policy experiment on maternal mortality, infant mortality, and stillbirth during the period of 1830–1894 in Sweden. Exploiting sharp changes or “discontinuities” across time and place in the availability of trained and licensed midwives as an exogenous source of variation, we find that a doubling of trained midwives led to a 20%–40% reduction in maternal mortality and a 20% increase in the uptake of midwife-assisted homebirths. The results thus suggest that a 1% increase in the share of midwife-assisted homebirths decreased maternal mortality by as much as 2%, which is a remarkable finding given that midwife training was only 6–12 months at that time. The results of this study contribute to the current debate about the most effective strategy to reduce the unacceptably high rate of maternal mortality in many developing countries, especially in low-resource settings.

Determination of Nitrogen and Phosphorus Partitioning within Components of the Biomass in a High Rate Algal Pond: Significance for the Coastal Environment of the Treated Effluent Discharge

1992 ◽  
Vol 25 (12) ◽  
pp. 207-214 ◽  
Author(s):  
N. J. Cromar ◽  
N. J. Martin ◽  
N. Christofi ◽  
P. A. Read ◽  
H. J. Fallowfield
Keyword(s):  
Dry Matter ◽  
Coastal Environment ◽  
High Rate ◽  
Nutrient Input ◽  
Nitrogen And Phosphorus ◽  
Loading Rates ◽  
Effective Strategies ◽  
Treated Effluent ◽  
Algae And Bacteria

Two High-Rate Algal Ponds were operated over residence times of 4 and 6 days respectively, at three COD loading rates equivalent to 600, 350 and 100 kg ha−1d−1 from early September to late October 1991. Samples of pond N and P feed were analysed to obtain nutrient input values to the system. Pond filtrates were also analysed for soluble nutrients. The pond biomass was separated into constituent components of algae and bacteria. Following separation, the discrete fractions were analysed for dry matter, chlorophyll content, and paniculate carbon, hydrogen, nitrogen and phosphorus. Nitrogen and phosphorus balances were then calculated which were used to partition the nutrients into soluble and paniculate phases, and to further separate the paniculate phase into algal and bacterial components. The partitioning of these nutrients, responsible for eutrophication, enables the calculation of removal rates of N and P from the pond systems and makes possible more effective strategies for the removal of the nutrient-rich biomass from receiving water bodies.

Integrated mechanical, biological and physico-chemical treatment of liquid manure streams

2000 ◽  
Vol 41 (12) ◽  
pp. 175-182 ◽  
Author(s):  
S. Kalyuzhnyi ◽  
V. Sklyar ◽  
J. Rodriguez-Martinez ◽  
I. Archipchenko ◽  
I. Barboulina ◽  
...  
Keyword(s):  
Effective Means ◽  
Uasb Reactor ◽  
Pig Manure ◽  
First Year ◽  
Liquid Manure ◽  
Nitrogen And Phosphorus ◽  
Physico Chemical ◽  
Feasible Alternative ◽  
Reactor Operating ◽  
Nitrogen Elimination

The results obtained during the first year of execution of a joint Russian-Dutch project “The development of integrated anaerobic-aerobic treatment of liquid manure streams with maximisation of production of valuable by-products (fertilisers, biogas) and re-utilisation of water” (1999–2001) are discussed. The application of a straw filter was an effective means to separate the solid and liquid fractions of diluted pig manure wastewater and resulted in the removal of a significant part of the dry matter, total nitrogen and phosphorus (65, 27 and 32%, respectively). From the filtrate generated, 60–80 % of the COD was removed in a UASB reactor operating at 20–30°C. Up to 66% of phosphate was precipitated after air stripping of the CO2 from the anaerobic effluents. Ammonia was efficiently removed (&gt;99%) from the anaerobic effluents using zeolite (Ural laumantite) as an ion exchanger. However, the N-content of the resulting zeolite was too low to be used as a fertiliser. A feasible alternative for nitrogen elimination involved nitrification of the anaerobic effluent followed by denitrification in a UASB reactor using the COD of the filtrated manure wastewater as carbon source.

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