Metabolic removal of phosphate from sewage effluent

Eutrophication, or fertilization, has become a major water pollution problem associated with the discharge of mineral-rich sewage eflluent. A metabolic process to remove dissolved phosphate from sewage through the action of sewage microorganisms is under development. The process, unlike other proposed solutions to the problem, would not require tertiary treatment of the sewage. Laboratory studies have produced promising data. Early reports from municipal sewage treatment plants confirm the expectation that the process may be feasible for widespread use.     

Quinone profiling of bacterial communities in natural and synthetic sewage activated sludge for enhanced phosphate removal

Respiratory quinones were used as biomarkers to study bacterial community structures in activated sludge reactors used for enhanced biological phosphate removal (EBPR). We compared the quinone profiles of EBPR sludges and standard sludges, of natural sewage and synthetic sewage, and of plant scale and laboratory scale systems. Ubiquinone (Q) and menaquinone (MK) components were detected in all sludges tested at molar MK/Q ratios of 0.455 to 0.981. The differences in MK/Q ratios were much larger when we compared different wastewater sludges (i.e., raw sewage and synthetic sewage) than when we compared sludges from the EBPR and standard processes or plant scale and laboratory scale systems. In all sludges tested a Q with eight isoprene units (Q-8) was the most abundant quinone. In the MK fraction, either tetrahydrogenated MK-8 or MK-7 was the predominant type, and there was also a significant proportion of MK-6 to MK-8 in most cases. A numerical cluster analysis of the profiles showed that the sludges tested fell into two major clusters; one included all raw sewage sludges, and the other consisted of all synthetic sewage sludges, independent of the operational mode and scale of the reactors and the phosphate accumulation. These data suggested that Q-8-containing species belonging to the class Proteobacteria (i.e., species belonging to the beta subclass) were the major constituents of the bacterial populations in the EBPR sludge, as well as in standard activated sludge. Members of the class Actinobacteria (gram-positive bacteria with high DNA G+C contents) were the second most abundant group in both types of sludge. The bacterial community structures in activated sludge processes may be affected more by the nature of the influent wastewater than by the introduction of an anaerobic stage into the process or by the scale of the reactors.     

Dissolution of rabbit zona by sperm acrosomal extract: effect of calcium (1).

The acrosomal extracts from rabbit spermatozoa were more effective in dissolving the zona pellucida of the rabbit ova in the absence than in the presence of Ca2+. The extracts had high proteolytic activity but low esterolytic activity at alkaline pH in which pH effective zona hydrolysis occurred. The results suggest that acrosomal proteinases in addition to acrosin may be involved in the zona penetration.     

Pretreatment of switchgrass for sugar production with the combination of sodium hydroxide and lime

Sodium hydroxide (NaOH) and lime (Ca(OH)₂) were innovatively used together in this study to improve the cost-effectiveness of alkaline pretreatment of switchgrass at ambient temperature. Based on the sugar production in enzymatic hydrolysis, the best pretreatment conditions were determined as: residence time of 6 h, NaOH loading of 0.10 g/g raw biomass, NaOH addition at the beginning, Ca(OH)₂ loading of 0.02 g/g raw biomass, and biomass wash intensity of 100 ml water/g raw biomass, at which the glucose and xylose yields were respectively 59.4% and 57.3% of the theoretical yields. The sugar yield of the biomass pretreated using the combination of 0.10 g NaOH/g raw biomass and 0.02 g Ca(OH)₂/g raw biomass was found comparable with that of the biomass pretreated using 0.20 g NaOH/g raw biomass at the same conditions, while the chemical expense was remarkably reduced due to the low cost of lime and the reduced loading of NaOH.     

Genospecies ofAcinetobacter isolated from activated sludge showing enhanced removal of phosphate during pilot-scale treatment of sewage

Summary Bacteria were isolated from activated sludge showing enhanced removal of phosphate after several months operation of a pilot-scale sewage-treatment plant. Isolates were obtained by colony picking or micro-manipulation of clusters of cells and those identified genetically (i.e. by transformation) asAcinetobacter belonged mostly (78%) to a single genospecies.     

The effect of various iron hydroxide concentrations on the anaerobic fermentation of sulfate-containing model sewage

The addition of iron hydroxide and iron-reducing bacteria into a fermenter for anaerobic processing of sulfate-containing sewage was shown to decrease sulfate reduction and sulfide concentration, while increasing the total organic carbon (TOC) and methane production. The effect of iron (III) in sulfate-containing sewage depended on its dose, which can be expressed as molar ratio Fe(III)/SO4(2-). Sulfide concentration increased monotonically, reaching 91 mg/l and 45 mg/l after 15 days of processing at Fe(III)/SO4(2-) ratios of 0.06 and 0.5, respectively. However, soluble sulfide production was not observed at ratios equaling 1 and 2. At ratios of 0.06, 0.5, 1, and 2, the maximum rates of TOC removal were 0.75, 1.15, 1.39, and 1.55 g TOC/g of organic matter (OM) per 1 h. Methane production rates were 0.039, 0.047, 0.064, and 0.069 mg/g OM per 1 h, with the mean relative amounts of methane in the biogas being equal to 25, 41, 55, and 62%, respectively. These data can be applied to the development of new methods of anaerobic purification of sulfate-containing sewage.     

Nature of the calcium effect in phosphate uptake by barley roots

Summary The rates of phosphate uptake of young intact plants were measured in solution at concentrations between 3.2×10^–7 M and 3.2×10^–5 M KH₂PO₄. The addition of 0.005 to 0.01M CaCl₂ increased the uptake rates to values of up to 4 times those of controls. The increases in uptake relative to the controls were most marked at the lowest phosphate concentrations. The addition of KCl also increased the uptake rates, but to a much smaller extent. The results are analyzed by the enzyme kinetic theory, and it is concluded that the uptake of phosphate at low ionic strengths is impeded by negative potentials at the root surface.The experimental results in this letter have appeared in a thesis.     

不同植物构成的人工湿地对生活污水中氮的去除效应

测定由不同植物构成的人工湿地的氨态氮、硝态氮和亚硝态氮含量,对比不同植物对生活污水中氮的去除效率.结果表明,与不种植物的人工湿地相比,由风车草[Cyperus alternifolius L. ssp. flabelliformis (Rottb.) Kiikenth.]、香根草[Vertiveria zizanioides (Linn.) Nash]、芦苇(Phragmitas communis Trin.)和美人蕉(Canna indica Linn.)构成的人工湿地对氨态氮去除率分别提高6%、8%、11%和14%;对硝态氮去除率分别提高5%、6%、13%和9%;对亚硝态氮去除率分别提高5%、7%、10%和7%,说明种植芦苇和美人蕉的人工湿地对生活污水中的氮具有较好的去除效果.     

The primary structure of electric ray hemoglobin (Torpedo marmorata). Bohr effect and phosphate interaction

The blood of the Electric Ray contains a number of hemoglobin components. The primary structures of the alpha- and beta-chains of the main components are presented. These chains were purified by high-performance liquid chromatography, using a new buffer system. The alpha-chains consist of 141 residues, and the beta-chains of 142 residues; both are unblocked. The phylogenetic distances from human alpha- and beta-chains are 55% and 64% amino-acid exchanges, respectively. The relationship between primary structure and the lack of both a Bohr effect and any effector affinity is discussed, and interpreted on a molecular level with reference to the sequence presented. For the Bohr effect, the mutation beta 89 Asp----Lys is significant, while the mutations beta 2 His----Ser, beta 82 Lys----Asn and beta 142 His----Cys are important for the lack of effector affinity.     

Citrus leafminer (Lepidoptera: Gracillariidae) density: effect on yield of 'Tahiti' lime

The relationship between damage by citrus leafminer, Phyllocnistis citrella Stainton, and 'Tahiti' lime yield were investigated in a 15-yr-old and a 5-yr-old lime orchard. Citrus leafminer population densities were controlled by insecticide applications of abamectin plus FC 435 oil, abamectin plus FC435 oil plus imidacloprid, and methomyl. The control was not treated. To ensure adequate citrus leafminer densities, adult citrus leafminer were periodically released in the experimental plots during fall and winter. For the 15-yr-old trees, the least amount of leaf area damage occurred in the abamectin plus FC 435 oil plus imidacloprid (1.9%) and the abamectin plus FC435 oil (2.3%) treatments compared with the control treatment (10-21%). In the 5-yr-old orchard, the least amount of leaf area damaged occurred in the abamectin plus FC 435 oil plus imidacloprid (0.4%) and the imidacloprid (0.1%) treatments compared with the control (20.85%). The percentage of leaf area damaged was linearly correlated with the average number of mines per leaf, average mine days, and cumulative mine days in both orchards. In both orchards, the percentage of leaf area damaged and cumulative mine days was linearly correlated with the number of fruit per tree and total fruit weight per tree. Calculating the economic injury levels indicated that 16-23% and 18-85% of leaf area damaged caused significant yield reductions in 15-yr-old and 5-yr-old trees, respectively.     

Bone regeneration: molecular and cellular interactions with calcium phosphate ceramics

Calcium phosphate bioceramics are widely used in orthopedic and dental applications and porous scaffolds made of them are serious candidates in the field of bone tissue engineering. They have superior properties for the stimulation of bone formation and bone bonding, both related to the specific interactions of their surface with the extracellular fluids and cells, ie, ionic exchanges, superficial molecular rearrangement and cellular activity.     

Trends in organic micropollutants removal in secondary treatment of sewage

Organic micropollutants (OMPs) comprise a wide group of substances highly consumed in modern societies. There has been a growing social and scientific interest on OMPs in wastewaters in the twentyfirst century. This research paper has identified the evolution of the research trends in the period 2001–2017 on OMPs fate during secondary wastewater treatment. These trends have moved from a global perspective on the occurrence of OMPs in wastewaters to more specific research focussed on understanding their behaviour during advanced treatment processes. Based on a bibliometric analysis carried out using one of the leading scientific databases, pharmaceuticals have been identified as the main group of OMPs. An increasing number of publications have been released on the fate of pharmaceuticals in wastewater with a growing number of countries involved: from 38 publications belonging to 14 countries in first 5-year period analysed (2001–2005) up to 138 from 42 countries only in the last 2 years (2016–2017). The main operational conditions in wastewater treatment plants influencing the removal of OMPs, as well as the mechanisms involved depending on the physico-chemical characteristics of the substances are reviewed. The paper also considers the role of microbial populations, as well as technological and operational features in OMPs abatement. Finally, a specific section is dedicated to the metabolic and cometabolic biotransformations of some OMPs taking place under heterotrophic, nitrifying and anaerobic conditions, a more novel research trend explored more recently.     

Renal clearance of phosphate and calcium in vitamin D-deficient chicks: effect of calcium loading, parathyroidectomy, and parathyroid hormone administration.

Serum and renal clearance values of phosphate and calcium were measured and compared in 4 week-old vitamin D-deficient and vitamin D-replete chickens (Gallus gallus). D-deficient chicks had significantly lower body weights and serum calcium values; however, their renal functions were not different from D-replete controls. Serum calcium values in D-deficient birds did not change in response to parathyroid hormone (PTH) administration; however, they did drop significantly in response to parathyroidectomy (PTX). Serum phosphate values of D-deficient birds, but not D-replete birds, rose significantly after PTX. Clearance of phosphate is known to increase after administration of PTH. This conspicuous effect was absent in PTH-injected vitamin D-deficient chickens. PTX caused the excretion of phosphate to drop in both D-deficient and D-replete birds to near zero. Conversely, PTX of both D-deficient and D-replete chickens stimulated the excretion of more calcium than in controls. Calcium loading elevates the fractional excretion of calcium in both D-deficient and D-replete birds. It also causes a decrease in phosphate excretion in both groups, presumably by inhibiting the secretion of PTH. PTH administration to D-replete, calcium-loaded birds caused increased phosphate excretion (as it did in normal controls), an effect that was not seen in similarly treated D-deficient birds. Therefore, most renal functions studied after calcium loading, PTH administration, or PTX are not altered by vitamin D deficiency in the chicken. The major significant finding is that vitamin D-deficient chickens do not excrete increased amounts of phosphate in response to PTH stimulus.