Reduce Phosphorus Release Research Articles

Addressing Phosphorus Waste in Open Flow Freshwater Fish Farms: Challenges and Solutions

Legislation and interest exists to protect and restore freshwater and marine ecosystems from the environmental impact of aquaculture. However, aquaculture-induced eutrophication remains a major environmental concern. Water soluble phosphorus, uneaten feed, feces, and metabolic waste from farmed fish increase phosphorus concentrations in adjacent waters. In open freshwater fish farms, in particular, the effects can be more immediate, as excess phosphorus is introduced directly into ecosystems. Several intestinal enzymes, transporters, and regulating factors have been implicated in farmed fish dietary phosphorus retention. For example, alkaline phosphatase and other transporters aid in the absorption of phosphorus in the anterior intestine, while pH, calcium, and vitamin D influence these enzymes and transporters. This process may also be influenced by intestinal morphology and the gut microbiome. To reduce phosphorus pollution from open flow fish farms, a thorough understanding of the processes that affect nutrient retention and absorption, as well as the impact of dietary factors, anti-nutritional substances, and intestinal morphology, is required. Aquaculture can be made more sustainable by reducing phosphorus release. This can be achieved by optimizing feed composition, adding functional feed ingredients, managing gut health, and treating effluent aquaculture waters with bioremediation and absorbing materials. Anti-nutritional factors can be mitigated through processing and through the use of functional feed additives. Addressing these issues will reduce aquaculture’s environmental impact, ensuring aquatic ecosystem health and global food security. In addition, treating effluent aquaculture waters with bioremediation and absorbing materials can remove phosphorus from the water, preventing it from entering the environment. This can further reduce the environmental impact of aquaculture and help to ensure the sustainability of this sector.

Comprehensive assessment of flocculation conditioning of dredged sediment using organic polymers: Dredged sediment dewaterability and release of pollutants

Dredged sediment contains various contaminants that are released during the process of dewatering and subsequent utilization. In this study, two organic polymers—chitosan (CS) and cationic polyacrylamide (CPAM) both in samples of varying molecular weights (MWs)—were used as flocculants to improve dewatering and rheological behaviors of dredged sediment, and floc properties were characterized to unravel the mechanisms of flocculation treatment. Moreover, pollutant transfer and release in the flocculation-dewatering process was investigated. Compared to CPAM, CS had better performance in dredged sediment dewatering, and more compact flocs were produced after treatment. The flocculated sediment belonged to the type of yield dilatant fluid and showed good shear resistance. Three-dimensional excitation–emission matrix spectroscopy and PARAFAC showed that protein-like substances were removed after treatment. The MW of CS had insignificant effects on flocculation performance, whereas CPAM removal efficiency for protein-like substances was increased at higher MWs, which may be related to the adsorption bridging effect of CPAM polymer chains. There were significant correlations between the dewatering performance of sediments, MW distribution of organics and rheological properties. CS and CPAM treatments caused the transformation of Fe/Al-P into CaP, which could reduce phosphorus release and its ecological risk. The flocculants contributed to the formation of carbonate-bound forms of As, Cr, Pb, and Ni. Ecological risk assessment results of the geo-accumulation index showed that medium- and low-MW CS reduced risk of sediment contamination, whereas CPAM and high-MW CS increased the ecological risk. CS had a greater effect on the release of VOCs than CPAM, with an increased release of total VOCs at higher flocculant MWs. The study was helpful to understand the dewatering mechanism of dredged sediment and provided a new strategy for pollution release management in sediment dewatering.

Lime application to reduce phosphorus release in different textured intact and small repacked soil columns

Phosphorus (P) losses from agricultural fields through leaching are the main contributors to eutrophication of lakes and rivers in North America. Adoption of P-retaining strategies is essential to improve the environmental quality of water bodies. The main objective of this study is to evaluate lime as a soil amendment in reducing phosphorus concentration in the leachate from three common soil textures with neutral to alkaline pH. Phosphorus leaching from undisturbed soil columns (10 cm in diameter and 20 cm deep) as well as small repacked columns was investigated and compared in this study. Lime (high calcium hydrated lime) at the rate of 1% by air-dried soil mass was applied to the topsoil of the columns. Both sets of experiments followed a full factorial design with two factors of soil texture at three levels (sandy loam, loam, and clay loam) and treatment at two levels (control and limed) with three replicates. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy was performed on the control and limed soil samples to confirm the formation of calcium phosphate compounds. For both intact and repacked columns, dissolved reactive phosphorus (DRP) concentrations in the leachates from limed sandy loam and limed loam soil columns was significantly reduced, while DRP in the limed clay loam column leachates was not changed. Elemental mapping demonstrated that in limed sandy loam and loam soils, the calcium loadings on the soil surface were always linked with phosphorus. The formation of calcium phosphate compounds and the increased phosphate adsorption on the soil surface through Ca bridging could be the two main phosphorus-lime retention mechanisms. Total dissolved phosphorus (TDP) in the leachates of limed loam and limed clay loam indoor intact and repacked columns was reduced, while there was no change in that of the sandy loam soil. In finer textured soils, lime can increase TDP retention through the immobilization of organic phosphates. The impact of lime application on DRP and TDP varied with the soil texture. The lime-induced reduction in the DRP and TDP was variable between the intact and repacked columns demonstrating the importance of soil structure on phosphorus and lime interactions in the soil. Overall, lime application at the studied rate can be considered a promising soil amendment in mitigating phosphorus loss from non-calcareous neutral to alkaline soils.

Capping 기술을 이용한 하천 및 호소 퇴적토의 인 용출 저감 효과 분석

Contaminants such as organic matters, nutrients and toxic chemicals in rivers and lakes with a weak flow rate are first removed from the water and accumulated in the sediments. Subsequently, they are released into the water column again, posing direct/indirect adverse effects on the water quality and aquatic ecosystems. In particular, phosphorus is known to accelerate the eutrophication phenomenon when it is released into the water column via physical disturbance and biological/chemical actions as one of important materials that determine the primary production of aquatic ecosystems and an element that is stored mainly in the sediments in the process of material circulation in the body of water. In this study, the effect on reducing phosphorus release in sediments was analyzed by applying different capping materials to lake water, where the effect of aquatic microorganisms is taken into account, and to distilled water, where the effect of microorganisms is excluded. The experimental results showed that capping with chemical materials such as Fe-gypsum and SiO2-gypsum further reduced the phosphorus release by at least 40% compared to the control case. Composite materials like granule gypsum+Sand showed over 50% phosphorus release reduction effect. Therefore, it is determined that capping with chemical materials such as granule-gypsum and eco-friendly materials such as sand is effective in reducing phosphorus release. The changes in phosphorus properties in the sediments before and after capping treatment showed that gypsum input helped to change the phosphorus that is present in lake sediments into apatite-P, a stable form that makes phosphorus release difficult. Based on the above results, it is expected that the application of capping technology will contribute to improving the efficiency of reducing phosphorus release that occurs in river and lake sediments.

The effects of red soil in removing phosphorus from water column and reducing phosphorus release from sediment in Lake Taihu

A natural red soil and a lanthanum-modified soil (LMS) were tested to compare their phosphorus (P) adsorption capacities and their effectiveness in removing P from the water column and reducing P release from sediment. The equilibrium of P adsorption demonstrated that the maximum P adsorption for the soil was 1.29 and 2.22 mg g(-1) at pH 8.5 and 5.5, respectively, and for the LMS these were increased by 45.6 and 77.6% at pH 8.5 and 5.5, respectively, indicating that the soil was effective in P adsorption and the doping of lanthanum could substantially increase P adsorption. The sediment-water column incubation showed that, due to the P adsorption of the soil and LMS, the total P in the water column decreased by 58.5, 60.6, 68.2 and 77.2% for 180 g m(-2) soil, 900 g m(-2) soil, 180 g m(-2) LMS and 900 g m(-2) LMS treated systems, respectively, in a short time (6 h), and the capping layer substantially reduced the P release from sediment during column incubation, indicating that the soils were effective in reducing internal P load. However, considering the cost of LMS, the natural soil was suggested to be a cost-effective material to control internal P load.

Reduction of phosphorus release from high phosphorus soil by red mud

The high phosphorus levels cause the release of phosphorus from soils, thereby increasing the potential for phosphorus export to adjacent water bodies. The loss of phosphorus from soils to surface waters is a major source of water quality impairment. Therefore, soil phosphorus immobilization seems necessary. In this study, red mud (RM) was employed to immobilize phosphorus in a typical agricultural soil. It was found that phosphorus was effectively immobilized by RM. Batch leaching experiments showed that RM reduced phosphorus release from 14.38 to 2.56 mg/kg when soil was amended with 1% RM. Column leaching experiments showed that RM reduced the total amount of phosphorus released from 36.73 to 18.79 mg/kg during the investigated period. Sequential chemical extraction results indicated that RM amendment transformed H2O-P into more stable fractions. The results suggested that application of RM amendment to soils could significantly immobilize soluble phosphorus, reducing phosphorus release to the environment.

Anthropogenic phosphorus flow analysis of Lujiang County, Anhui Province, Central China

Anthropogenic phosphorus load in the aquatic environment of Lujiang County, central China, may be a serious problem, greatly contributing to surface water eutrophication. Using substance flow analysis, this study develops a phosphorus-flow analytical model to trace the pathways of this limiting nutrient throughout Lujiang's socioeconomic system. The model includes six major subsystems: extraction, phosphorous chemical industry, agriculture, animal husbandry, human consumption, and phosphorous waste management. We conducted qualitative and quantitative analyses of the primary phosphorous flows and stocks within these subsystems in Lujiang County over 2008. Approaches to data include statistical reports and literature reviews, face-to-face interviews and questionnaire-based surveys. The results show the total phosphorus input and output were 8311.5 tons and 5664.6 tons, respectively, in Lujiang in 2008, resulting in a phosphorus surplus of 2646.9 tons in the socioeconomic system. The phosphorus load in the recipient waters, as part of the total phosphorus output, was estimated to be 1666.7 tons. Large-scale livestock operations contributed the most phosphorus to local surface waters, accounting for 55.8% and followed by human consumption (23.0%) and agriculture (21.2%). Consequently, it should be of central concern for policy makers to improve phosphorous reuse efficiency in order to reduce phosphorus release into the aquatic environment. Limitations of the methodology and data are also discussed.

Lake sediment treatment with aluminum, iron, calcium and nitrate additives to reduce phosphorus release

Treatment of lake sediments with salts is a promising approach for preventing phosphorus release from sediments. Five 35-d treatments of undisturbed sediment cores in the East Lake, Wuhan, China were applied under anoxic conditions: nothing added (control), Al2(SO4)3 added, FeCl3 added, CaCl2 added, and NaNO3 added. To identify changes in the P binding sites in the sediment caused by the treatments, different P binding forms were extracted from the sediment before and after the treatments. We found that the mean P release rates for anoxic treatments with Al2(SO4)3, FeCl3, CaCl2 and NaNO3 were −0.6, 0.03, 0.6 and 2.6 mg/(m2·d), respectively, while the P release rate with no additives was 7.3 mg/(m2·d). In suboxic conditions, the concentration of total phosphorus (TPaverage 657 mg/kg) in sediment was much lower than that of untreated sediment (TPaverage 688 mg/kg) and treatments with salts (TP(Al2(SO4)3) 793 mg/kg, TP(FeCl3) 781 mg/kg, TP(NaNO3) 802 mg/kg, TP(CaCl2) 747 mg/kg). We also found that adding CaCl2 prevented P release because of apatite formation and because PCa (Ca bound P) increased at the sediment surface. Addition of Fe3+ and NO3− to the sediment increased the amounts of PFe, Mn (Redox-sensitive P, mostly Fe and Mn compounds), since iron oxide has the ability to combine P. Addition of Al2(SO4)3 increased the fraction of PAl, Fe (P bound to metal oxides (Al, Fe)) and decreased the P and Fe in the water above the anoxic sediment, showing the greater ability of Al in binding P. The results showed that Al2(SO4)3, FeCl3, CaCl2 and NaNO3 all had an effect in controlling phosphorus release. The effect was related to the forms of phosphorus existing in the sediment before treatment and the forms resulting after adding the four reagents. The combination of Al3+ or Fe3+ with NO3− promises to be a reasonable chemical treatment for increasing the P retention capacity of sediments in eutrophic lakes. If chemical treatment is combined with bioremediation, the aim of environmental repair may be achieved.

Application of Gypsum Granule as a Capping Material to Reduce Phosphorus Release from Sediment of Lake Paldang

In this study, the capping effects of granular gypsum (Ca2SO4·2H2O) and sand on sediment and water column were evaluated in in-situ experiments in Lake Paldang. The results indicate that capping treatment is very effective for the restoration of eutrophied lake. It was demonstrated that phosphorus, T-N and T-P concentration in the water column of treated basin was relatively lower than control basin. As a consequence of reduction of nutrient concentration by capping treatment, chlorophyll-a concentration in treated basin was considerably lower than control basin. The chlorophyll-a concentration in water column could be reduced to 52% and 25% as compared to control basin, respectively, by the capping treatment with gypsum and sand. From the experimental results, it was concluded that gypsum was more effective capping material than sand for controlling of nutrients and chlorophyll-a. In addition, capping with gypsum bring calcium cation into sediment, which offer more site for phosphorus to bind. In case of the capping with gypsum, apatite P composition, mainly consist of Ca boun P, in the sediment increased from 24% to 43% for the two month of operation.

Reducing phosphorus release from paddy soils by a fly ash-gypsum mixture

A mixture of fly ash and phospho-gypsum (50:50, wt wt −1) was selected to study its potential to supply Ca and Si to rice while reducing B toxicity. We expected that the high Ca content in this mixture might convert water-soluble P to less soluble forms and thereby reduce the loss of soil P to surface runoff. The mixture was applied at rates of 0, 20, 40, and 60 Mg ha −1 in two paddy soils of contrasting textures (silt loam in Yehari and loamy sand in Daegok). The mixture significantly reduced water-soluble phosphate (W-P) in the surface soils by shifting from W-P and iron bound-P (Fe-P) to calcium bound-P (Ca-P) and aluminum bound-P (Al-P) during rice cultivation in both soils. Lancaster and Mehlich 3 extractable P increased significantly with application rate due to high contents of P and Si in the mixture. Mixtures of fly ash and phospho-gypsum should reduce P loss from rice paddy soils and increase soil fertility.

Relative Efficacy of a Drinking‐Water Treatment Residual and Alum in Reducing Phosphorus Release from Poultry Litter

Amending poultry litter with alum (aluminum sulfate) effectively reduces soluble phosphorus (P) concentrations, but the practice can be expensive. Aluminum (Al)‐based drinking‐water treatment residuals (WTRs) can be obtained free of charge and are enriched in Al hydr(oxides) that make them efficient P sorbents. Substituting Al‐WTRs for alum would be a cost‐effective practice to reduce soluble P in manures when compared with alum‐only use. The research studied the reductions in soluble P, Al, and total organic carbon (TOC) concentrations in suspensions prepared by mixing variable Al‐WTR and alum rates (0 to 25% by weight) with poultry litter. Suspensions were maintained at pH of 6.5 during the sorption step, and allowed to react up to 50 d, without shaking. On a per‐mole of oxalate‐extractable Al basis, the Al‐WTR was nearly as effective as alum in reducing P release. Increasing mixed alum/WTR mass loads resulted in greater soluble P reduction, simply due to increased molar Al/P ratios. Contact time did not significantly influence soluble P reduction. Two significant advantages of Al‐WTRs compared to alum indicated by this study are cost effectiveness and significantly less release of dissolved Al. Soluble Al and TOC concentrations were least for suspensions with the lowest soluble P levels, suggesting that P was removed from solution as an organo‐Al‐P amorphous phase. The amount of P desorbed from the mixtures decreased to <1% with increasing molar Al/P ratios ≥1. Results suggest that Al‐WTR application with or without alum can reduce soluble P in poultry litter; however, field validation of the amendment effectiveness is needed. This research was supported by the Florida Agricultural Experiment Station and a grant from a USEPA grant CP‐82963801, and approved for publication as Journal Series No. R‐10112.

Reducing Phosphorus Release from Paddy Soil by Coal Ash and Phospho-Gypsum Mixture

As a silicate source to rice, a coal ash was selected and mixed with phosphor-gypsum (50:50, wt ) to reduce the potential of boron toxicity and to supply calcium element. We expected that high con tent of calcium in this mixture might convert water-soluble phosphorus to less soluble forms and then reduce the release of soil phosphorus to surface runoff. The mixture was applied with the rate of 0, 20, 40, and 60 Mg in paddy soil (Nagdong series, a somewhat excessively drained loamy fine sand) in Daegok, Jinju, Korea The mixture reduced significantly water-soluble phosphorus (W-P) in the surface soils by shifting from W-P and Fe-P to Ca-P and Al-P during whole rice cultivation. In contrast with W-P, plant available phosphorus increased significantly with the mixture application due to high content of phosphorus and silicate in the mixture. The mixture of coal ash and phosphor-gypsum (50:50, wt ) would be a good alternative to reduce a phosphorus export in rice paddy soil together with increasing rice yields.

Sediment treatment with a nitrate-storing compound to reduce phosphorus release

The application of Fe(III), in combination with sediment oxidation by NO(3)(-), is an accepted procedure to manage stratified eutrophic lakes by controlling the phosphorus release from sediments into overlying water. Depox(R), a newly developed compound, consisting of Fe(III) and NO(3)(-), has a storage effect for NO(3)(-). NO(3)(-) is released slowly, hence the disadvantageous high solubility of NO(3)(-) in water can be retarded. The compound was added to water as a suspension which quickly flocculated and precipitated. Within 3 weeks, NO(3)(-) was desorbed from the Depox(R) compound in deionized water. After application in lakes, the NO(3)(-) availability on the sediment surface was prolonged for 2 months. After treatment, P release from the sediment and microbial metabolism were investigated under laboratory conditions as well as in the mesocosm. P release was almost stopped in both cases during the experiment. SO(4)(2-) consumption was significantly lower after Depox(R) addition, and CH(4) production was completely suppressed by Depox(R) treatment in the laboratory, whereas in the enclosures SO(4)(2-) and also CH(4) concentrations at the sediment water interface did not change significantly between treated enclosures and controls.

Fish habitat requirements as the basis for rehabilitation of eutrophic lakes by oxygenation

AbstractEutrophic lakes often suffer from hypolimnetic oxygen depletion during summer and autumn, and the accumulation of reduced substances in the hypolimnion. The space fish can occupy is therefore reduced, and the potential for fish kills caused by toxic algae and the upwelling of anoxic water increases. Fish, such as coregonids, require at least 4 mg O2 L−1 to survive in the long‐term. This critical level has been postulated as one of the major goals for the rehabilitation of several eutrophic Swiss lakes. It was predicted that this oxygen criterion would reduce phosphorus release from the sediment and increase phosphorus retention, and re‐establish natural reproduction of coregonids. Rehabilitation measures applied to three eutrophic Swiss lakes were hypolimnetic oxygenation during summer stratification, and artificial mixing using compressed air to enhance circulation in winter. These lake‐internal measures carried out for more than 15 years showed the 4 mg O2 L−1 criterion can be achieved most of the time. The measures have led to an expansion of habitat for oxygen‐dependent organisms to greater depths. However, other goals were not attained, such as increasing phosphorus retention by the sediment. In addition, natural reproduction of coregonids could not be re‐established. Excessive oxygen consumption by the sediment, arising from the decomposition of deposited organic matter produced during summer, caused death by suffocation of coregonid eggs developing on the sediment. Thus rehabilitation of eutrophic lakes by oxygenating the hypolimnion and artificial mixing will not be successful, unless it is accompanied by lowering the nutrient loading and thus primary production and oxygen consumption by the sediment. Nevertheless, positive effects of lake aeration were the expansion of living space for fish and benthic invertebrates, and the prevention of fish kills by upwelling anoxic hypolimnetic water.

Use of active barriers to reduce eutrophication problems in urban lakes

Excessive concentration of phosphorus is one of the main causes of algal blooms and eutrophic conditions in lakes. In many urban lakes, it appears that a large proportion of the phosphorus in the water column comes from the sediments, particularly when these are anaerobic. Sub-aqueous capping is a relatively new method that has become an attractive option for isolating contaminated sediments from the environment, thus preventing or delaying the release of contaminants into surface waters. Active barrier materials (i.e. capping layers that consist of one or more reactive components) are gaining increasing attention for their greater efficiency in inactivating contaminants held in sediment layers. This paper reports laboratory bioreactor experiments to test the effectiveness of three forms of calcium carbonate (CaCO3) in reducing the release of phosphorus from anaerobic sediment from Lake Carramar, a small urban lake in Melbourne. Two of the CaCO3 active barrier materials tested proved to be quite effective, the most effective materials being the fine particle size, precipitated forms of CaCO3. Over the 20-day experimental period, a 2% layer of the German material SoCal reduced the amount of phosphorus released by almost 100 times over that occurring with no barrier. The Australian product ESCal, while not as effective as the SoCal, still reduced the phosphorus released by around 15 times that with no barrier. A finely ground Lilydale limestone was essentially ineffective in reducing phosphorus release from the sediments. A preliminary cost-benefit analysis suggests that SoCal is unlikely to be attractive for use in Australia, given the estimated application cost of around 3,800 dollars per tonne. However, although the ESCal is slightly less effective in retaining phosphorus, its potential application cost estimated at 2,000 dollars per tonne, makes it an attractive option. On the basis of these most promising preliminary results, we intend to further test the use of the ESCal. Further investigations will include: longer term laboratory studies using ESCal, optimisation of the barrier layer and methods for applying this material, mesocosms and full lake studies, and risk assessment studies to ensure there are no adverse ecological effects from its use.

Active Barriers to Reduce Phosphorus Release from Sediments: Effectiveness of Three Forms of CaCO3

Three forms of calcite—crushed limestone and two forms of precipitated calcite—were tested in laboratory bio-reactors as possible active barriers to prevent phosphorus release from sediments, and therefore reduce the risks due to algal blooms (or eutrophication). The two precipitated calcite materials proved to be quite effective at reducing the release of phosphorus from Lake Carramar sediments under anaerobic conditions. Over a 20-day period, a 2% (1.1 kg (CaCO3) m–2 layer of SoCal (a commercial product from Germany) reduced the amount of phosphorus released by almost 100 times over that occurring with no barrier. The Australian product (ESCal 2%), while not as effective as the SoCal, still reduced the phosphorus released by around 15 times that with no barrier. Limestone was ineffective in preventing the release of phosphorus. Mean phosphorus flux rates under anaerobic conditions were: control 66, SoCal 0.8, and ESCal 2.9 µmol (P) m–2 d–1. There is considerable scope to further optimize the conditions under which the ESCal calcite is formed to produce a product with smaller particle size and higher surface area than that tested here. Additionally, there is potential to precipitate the ESCal in situ and thus achieve even greater cost savings. Preliminary cost estimates are that it should be possible to dispense calcium hydroxide directly into the water column at around $A 200 per tonne, and then use a CO2 bubbler system to precipitate CaCO3 directly in the water column.

Suppression of phosphorus release from lake sediments by the addition of nitrate

An assessment was made of the effectiveness of nitrate in reducing phosphorus release from the anoxic sediments of a small dimictic lake, White Lough, N. Ireland. Laboratory experiments on sediment cores showed that nitrate delayed and reduced phosphorus release with an input of 61 gN m −2 causing complete suppression. The addition of 24 gN m −2 of nitrate to the sediment of White Lough resulted in a delay and reduction of phosphorus release similar to that observed in the laboratory core experiments. Sediment release of iron in the lake was also delayed and reduced but manganese release and the rate of hypolimnetic deoxygenation were unaffected by the nitrate addition. Ammonium release rates in the sediment cores and in the whole lake experiment did not vary with nitrate input. Comparing the costs of using nitrate or iron/aluminium salts to suppress sediment phosphorus release indicated that the nitrate method was at least 80% more expensive.

REDUCING SEDIMENT PHOSPHORUS RELEASE RATES IN LONG LAKE THROUGH THE USE OF CALCIUM NITRATE

ABSTRACT The effect of injecting different dosage rates of calcium nitrate into the bottom sediments of Long Lake in New Brighton, Minn., was observed in a laboratory study. The purpose of the study was to determine the minimum dosage necessary to reduce phosphorus release rates from the sediments to satisfactory levels. The study included measurement of sediment phosphorus release rates under both aerobic and anaerobic conditions, and evaluated the effect of adding ferric chloride to the sediments along with the calcium nitrate. The addition of ferric chloride was included in the study to determine if the iron available in the sediment was adequate to sorb the PO4 −3when oxidized conditions were provided. The study concluded that at least for the short term (90 days), injection of calcium nitrate could eliminate virtually all phosphorus release from the sediments previously releasing phosphorus at a rate of 7 mg P/m2/day, and actually result in the sediments becoming a sink for phosphorus in the water co...

The phosphatase activity and release of phosphorus during composting with fungal inoculants and in the presence of phosphate

The effect of inoculation with Aspergillus awamori and Paecilomyces fusisporus, and of the addition of soluble phosphate, on phosphatase activity during composting was studied. Inoculation increased phosphatase activity and the release of phosphorus. The addition of phosphate did not reduce phosphorus release in treatments without inoculation, but in inoculated samples it inhibited phosphorus release.