Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 3 de 3
Filter
Add more filters

Database
Language
Publication year range
1.
J Environ Manage ; 324: 116329, 2022 Dec 15.
Article in English | MEDLINE | ID: mdl-36183527

ABSTRACT

Phosphorus losses from agriculture have long generated concern due to the ecological impact on surface waters. Here tile-drained agricultural catchments are a critical source for concentrating and transporting phosphorus bioavailable forms or dissolved reactive phosphorus (DRP). Hence, edge-of-field technologies have been introduced to reduce DRP loads. Filter systems have received special attention due to their targeted approach using a permeable filter material (FM) rich in DRP sorbents. This review explores the performance and applicability of FMs in the aforementioned context because of the growing number of studies. An overall analysis revealed that sorption is preferable to precipitation for DRP retention at the edge-of-field, and that FM pH and particle size affect sorption properties and subsequently DRP retention and lifetime. Thus, FMs with predominant amounts of iron and/or aluminium can be recommended. Such materials generally have an appreciable availability of DRP binding sites, strong bonds with DRP and short reaction times, as well as low desorption, which lead to good operation. On the other hand, FMs with predominant amounts of calcium and/or magnesium are restricted to catchments with favourable conditions unless they have optimal reactivity for DRP. The review also found that hydraulic retention time plays a key role in the performance and applicability of FMs, especially in those dependent on precipitation reactions. Therefore, it is crucial that FMs are designed, constructed and managed according to the catchment conditions-including normally varying flow rates and DRP concentrations-in order to ensure successful operation. This reflects in long-term, high and steady net DRP retention along with low costs, thus improving the FM cost-effectiveness, besides discharging non-harmful effluents to aquatic ecosystems.


Subject(s)
Phosphorus , Water Movements , Ecosystem , Agriculture , Particle Size
2.
Water Res ; 247: 120792, 2023 Dec 01.
Article in English | MEDLINE | ID: mdl-37925858

ABSTRACT

Phosphorus (P) losses from tile-drained agricultural fields may degrade surface water quality by accelerating eutrophication. Among the different edge-of-field technologies, compact filter systems using different filter materials have been identified as potentially effective solutions for removing P from drainage water before discharge downstream. This study investigated the long-term (>696 days) P removal efficiency of 5 different filter materials in a column setup, using artificial drainage water (pH 6). Filter materials included two iron-based granulates (calcinated diatomaceous earth (CDE), ferric hydroxide granules (CFH)), and three calcium-based granulates (seashells, limestone, calcinated silicate/calcium oxide (Filtralite-P)). Experiments were performed under variable flow rates (0.037 and 1.52 L h-1; hydraulic retention time of 26-43 min and 18-30 h) and inlet P concentrations (0.14 and 0.7 mg L-1). An overall analysis revealed that the Fe-based materials achieved higher P retention than Ca-based materials. In particular, CFH was capable of retaining 99 and 98 % of the high and low inlet P concentrations, respectively. Conversely, limestone retained only 25 % of the high P load. CDE performed moderately well, independently of the inlet P concentration. Filtralite-P and Seashells performed well at high inlet P concentration but relatively poorly at low P concentration. The sensitivity of filter material P removal efficiency to variations in P loading was generally lowest for CFH and highest for limestone.


Subject(s)
Bays , Phosphorus , Iron , Calcium Carbonate , Silicates
3.
J Environ Qual ; 48(2): 322-329, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30951111

ABSTRACT

Vegetated buffer strips (VBS) between agricultural areas and surface waters are important retention areas for eroded particulate P through which they may obtain critically high degrees of P saturation imposing high risk of soluble P leaching. We tested topsoil removal and three harvesting frequencies (once, twice, or four times per year) of natural buffer vegetation to reduce P leaching with the aim to offset erosional P accumulation and high degrees of P saturation. We used a simple numerical time-step model to estimate changes in VBS soil P levels with and without harvest. Harvesting offset erosional deposition as it resulted in an annual ammonium oxalate-extractable P reduction of 0.3 to 2.8% (25-cm topsoil content) in soils of the VBS and thus, with time, reduced potential P leaching below a baseline of 50 µg L. Topsoil removal only marginally reduced potential leaching at two sites and not anywhere near this baseline. The harvest frequency only marginally affected the annual P removal, making single annual harvests the most economical. We estimate 50 to 300 yr to reach the P leaching baseline, due to substantial amounts of P accumulated in the soils. Even in high-erosion-risk situations in our study, harvesting reduced soil P content and the P leaching risk. We suggest harvesting as a practical and efficient management to combat P leaching from agricultural VBS, not just for short-term reductions of dissolved P, but also for reductions of the total soil P pool and for possible multiple benefits for VBS.


Subject(s)
Non-Point Source Pollution/prevention & control , Phosphorus/analysis , Water Pollutants, Chemical/analysis , Agriculture , Rivers , Soil , Soil Pollutants/analysis , Water Movements
SELECTION OF CITATIONS
SEARCH DETAIL