Long-term observations on the hydraulic performance of a combined capillary barrier-methane oxidation landfill cover system.

This study quantifies the field hydraulic performance of a dual-functionality landfill cover, combining microbial methane oxidation with water diversion using a capillary barrier. The investigated 500 m2 test field, constructed on a landfill in the Netherlands, consisted of a cover soil optimised for methane oxidation, underlain by a sandy capillary layer and a gravelly capillary block. Outflows from these layers were measured between 2009 and 2023. Average precipitation was 848 mm/a, evapotranspiration, diverted infiltration and breakthrough amounted to 504 (59.4 %), 282 (33.3 %) and 62 (7.3 %) mm/a, respectively. On average, the capillary barrier diverted 82 % of the inflow into the capillary layer. Breakthrough occurred mainly from October to March when evapotranspiration was low and the maximum water storage capacity of the cover soil was reached. During this period, inflow into the capillary barrier exceeded its diversion capacity, caused by the relatively high hydraulic conductivity of the cover soil due to its optimisation for gas transport. The diversion capacity declined drastically in the year after construction and increased again afterwards. This was attributed to suffusion of sand from the capillary layer into the capillary block and subsequent washout to greater depths or the influence of iron precipitates at the bottom of the capillary layer. The effect of a more finely grained methane oxidation layer on the hydraulic and methane oxidation performance should be investigated further. These measures could further improve the combined performance of the dual functionality landfill cover system under the given conditions of a temperate climate.

A new economic instrument for financing accelerated landfill aftercare.

The key aspects of landfill operation that remain unresolved are the extended timescale and uncertain funding of the post-closure period. This paper reviews the topic and proposes an economic instrument to resolve the unsustainable nature of the current situation. Unsustainability arises from the sluggish degradation of organic material and also the slow flushing of potential pollutants that is exacerbated by low-permeability capping. A landfill tax or aftercare provision rebate is proposed as an economic instrument to encourage operators to actively advance the stabilization of landfilled waste. The rebate could be accommodated within existing regulatory and tax regimes and would be paid for: (i) every tonne of nitrogen (or other agreed leachate marker) whose removal is advanced via the accelerated production and extraction of leachate; (ii) every tonne of non-commercially viable carbon removed via landfill gas collection and treatment. The rebates would be set at a level that would make it financially attractive to operators and would encourage measures such as leachate recirculation, in situ aeration, and enhanced flushing. Illustrative calculations suggest that a maximum rebate of up to ∼€50/tonne MSW would provide an adequate incentive.

Aprotinin prevents the development of the trauma-induced multiple organ failure in a chronic sheep model.

Trauma-induced multiple organ failure in sheep was prevented by aprotinin therapy. Multiple organ failure was induced in 16 female merino sheep by initial haemorrhagic shock and intramedullary femoral nailing (day 0), and 12 hourly injections of 0.75 micrograms/kg Escherichia coli endotoxin +0.7 ml/kg zymosan-activated plasma (days 1-5). In addition, the aprotinin group (n = 6) received simultaneous injections of 5 mg/kg (35 695 KIU/kg) aprotinin, whereas ten animals did not receive aprotinin and served as the control group (n = 10). Organ functions were monitored for a total of 11 days by measuring haemodynamic, cardio-respiratory and biochemical quantities of blood, urine and epithelial lining fluid. During the subsequent eleven day period, aprotinin induced a significant (p < 0.05) reduction of the pathological changes (development of multiple organ failure) seen in the control group. Thus, aprotinin prevented an alteration of cardiac function (cardiac index for control/aprotinin groups at day 1: 6.5/6.2, and at day 10: 10.47/7.0 1/min x m2), an impairment of lung function (mean pulmonary arterial pressure at day 1: 2.26/1.86, and at day 10: 3.83/2.13 kPa; epithelial lining fluid/plasma ratio of albumin concentrations as a direct marker of lung capillary permeability damage at day 0: 0.18/0.16, and at day 10: 0.45/0.15), a deterioration of liver function (plasma sorbitol dehydrogenase at day 0: 7.9/7.6, and at day 10: 29.6/7.4 U/1), but not of renal function (creatinine clearance at day 1: 91.4/66.1, and at day 10: 53.1/59.2 ml/min). Urinary aprotinin excretion increased up to day 3, then decreased rapidly despite further aprotinin administration. As a non-specific marker of cell damage, plasma lactate dehydrogenase indicated an aprotinin-induced organ protection (day 0: 501/409, and at day 10: 719/329 U/1). The neutrophil count and the measured chemiluminescence of neutrophils from the blood and epithelial lining fluid showed that aprotinin reduced the in vivo neutrophil activation, the alveolar neutrophil invasion, the production of inflammatory mediators, and the production of reactive oxygen metabolites during the passage of the capillary-interstitial-alveolar space by neutrophils.