Mercury removal from municipal secondary effluent with hydrous ferric oxide reactive filtration

This study evaluated the ability of hydrous ferric oxide reactive filtration (HFO-RF) to remove mercury (Hg) from municipal secondary effluent at four study sites. Pilot HFO-RF systems (136 m³ /day) at two sites demonstrated total Hg concentration removal efficiencies of 96% (inflow/outflow mean total Hg: 43.6/1.6  ng/L) and 80% (4.2/0.8 ng/L). A lightly loaded medium-scale HFO-RF system (950 m³ /day) had a concentration removal efficiency of 53% (0.98/0.46 ng/L) and removed 0.52 mg/day of total Hg and 2.2 μg/day of methyl-Hg. A full-scale HFO-RF system (11,400 m³ /day) yielded a total Hg concentration removal efficiency of 97% (87/2.7 ng/L) and removed an estimated 0.36 kg/year of Hg. Results suggest that the quality of secondary effluent, including dissolved organic matter content, affects achievable minimum total Hg concentrations in effluent from HFO-RF systems. Low HFO-RF effluent concentrations (<1 ng/L) can be expected when treating secondary effluent from suspended-growth biological treatment systems. PRACTITIONER POINTS: Trace levels of mercury in municipal secondary effluent can negatively impact receiving waters. Hydrous ferric oxide reactive filtration (HFO-RF) can remove mercury from municipal secondary effluent to levels below the Great Lakes Initiative discharge standard of 1.3 ng/L. Mercury removal to low concentrations (< 1 ng/L) using HFO-RF appears to be associated with secondary effluents with low dissolved organic matter content. HFO-RF can also remove total phosphorus and turbidity to low concentrations.

Phosphorus removal from municipal wastewater by hydrous ferric oxide reactive filtration and coupled chemically enhanced secondary treatment: part II--mechanism

The removal mechanism of a hydrous ferric oxide (HFO) reactive filtration (RF) process with coupled chemically enhanced secondary treatment (RECYCLE) for phosphorus removal from municipal wastewater (HFO-RF-RECYCLE) was examined. A 0.95-ML/d (0.25-mgd) demonstration of HFO-RF-RECYCLE was performed at a municipal wastewater treatment plant equipped with oxidation ditches and secondary clarifiers. Influent to the plant averaged 6.0 mg/L phosphorus, with a 3-month tertiary effluent average of 0.011 mg/L phosphorus. In addition to aqueous geochemical modeling, experiments with surface charge, scanning electron microscopy, adsorptive capacity, thermal desorption, and most probable number of iron(III)-reducing bacteria were performed on samples from the system, to determine the major phosphorus-removal pathways. Results suggest that, in addition to filtration of particulate phosphorus, the low tertiary effluent total phosphorus result was achieved by adsorption.

Phosphorus removal from municipal wastewater by hydrous ferric oxide reactive filtration and coupled chemically enhanced secondary treatment: part I--performance

This work examines the performance of a hydrous ferric oxide (HFO) reactive filtration (RF) process with coupled chemically enhanced secondary treatment (RECYCLE) for phosphorus removal from municipal wastewater (HFO-RF-RECYCLE). A 3-month, 0.95-ML/d (0.25-mgd) demonstration of HFO-RF-RECYCLE was performed at a municipal wastewater treatment plant equipped with oxidation ditches and secondary clarifiers. Influent to the plant averaged 6.0 mg/L phosphorus, with a tertiary effluent average of 0.011 mg/L phosphorus. Iron doses to the plant were low, at 5 mg/L. Inline recycling of HFO solution rejects to the plant influent resulted in a maximum 90.3%, dose-dependent reduction of phosphorus in the secondary effluent at 4.5 ML/d (1.2 mgd). Other results included reduction of total suspended solids and turbidity. A mass balance analysis was performed. We conclude that HFO-RF-RECYCLE may allow very low levels of phosphorus discharge from municipal wastewater treatment plants with a ferric-iron-based tertiary filtration process and residual recycling.

Snow sports related head and spinal injuries: an eight-year survey from the neurotrauma centre for the Snowy Mountains, Australia

Neurotrauma from snow-sports related injuries is infrequently documented in the literature. In Australia no collective data has ever been published. The aim of this study is to document the injury pattern of snow sports related neurotrauma admissions to The Canberra Hospital, the regional trauma centre for the Snowy Mountains. A computerised hospital record search conducted between January 1994 and July 2002 revealed 25 head and 66 spinal injury admissions. The incidence of severe injuries requiring referral to tertiary trauma hospital was estimated to be 7.4 per 100,000 skier-days and for head and spinal injury 1.8 per 1,000,000 skier-days and 5.6 per 1,000,000 skier-days, respectively. Collision with a stationary object was disproportionately associated with head injury ( [Formula: see text] ) and falling forward with spinal injury ( [Formula: see text] ). Snowboarders tended to sustain cervical fractures more often than skiers ( [Formula: see text] ). The importance of helmet usage in buffering the impact of head-on collision and the proposition of having both feet fastened to a snowboard in leading to cervical injury were highlighted.

Lumbar discectomy and the diabetic patient: incidence and outcome

Medical records of 363 patients who had a diagnosis of lumbar disc disease and were managed by a posterior approach lumbar discectomy over a 7 year period were reviewed: 33 patients had a preoperative diagnosis of diabetes, an incidence in this patient population of 9.1%. The results for these 33 patients who had a diagnosis of diabetes mellitus were compared with those of 33 age and sex matched nondiabetic (control) patients who had a similar operative approach. Twenty-five of the diabetic and 28 of t he control patients were available for long term follow up. The results were positive (good to excellent) for 24 of the 28 (86%) control patients and 15 of the 25 (60%) diabetic patients. Seven of the 25 (28%) diabetic patients had reoperation for recurrent disc herniation at the same level following the initial procedure compared with one of the 28 (3.5%) control patients.

Neurosurgery and iatrogenic transmission of Creutzfeldt-Jakob disease

The Neurosurgical Society of Australasia has not recommended that recipients of dura mater grafts be actively sought out and informed, but rather that neurosurgeons should attempt to discover for individual patients whether they have received dura mater grafts.

Cube copying after cerebral damage

The capacity of patients with cerebral lesions to copy a picture of a cube, as opposed to a nonrepresentational figure of similar structural complexity, was examined. Patients with copying disability showed greater impairment for the cube than the noncube whereas patients without copying impairment and controls performed equally on the two figures. It was concluded that the copying-deficit patients had particular difficulty in drawing 3-dimensional figures and that the copying deficit was not simply one of formulating the sequence of steps necessary to produce a complex as opposed to a simple abstract form. The results suggest that copying-disability patients may experience particular difficulty in encoding the pictorial structure of a model which depicts a three-dimensional object. The occurrence of errors of intellectual realism in cube copying (which also occur in children's drawings) was noted and it was suggested that the patients were experiencing difficulty in perceptually isolating the picture structure from the picture content.

Cerebrospinal fluid rhinorrhoea during treatment of pituitary tumours with bromocriptine

Bromocriptine is widely used in the treatment of hyperprolactinaemia. It has also been shown to be effective in reducing the size of large pituitary tumours, particularly those secreting prolactin. We describe CSF rhinorrhoea in two such patients during treatment with bromocriptine and believe that this complication developed as a result of contraction of the tumour exposing a defect in the sella floor. The possibility of this complication, especially in patients with downward extension of tumour, should be noted.

Radiological abnormalities in temporal lobe epilepsy with clinicopathological correlations

In 73 patients with drug-resistant temporal lobe epilepsy submitted to an unilateral anterior temporal lobectomy the radiographs were studied to see if there were any correlation with the pathology subsequently found and with the outcome of the operation. A small middle cranial fossa, focal calcification, and temporal horn displacement are often better indices of the underlying pathology than temporal horn dilatation alone. In a small number of cases, however, radiological changes were seen on the side opposite to an unilateral EEG focus, thus suggesting bilateral disease.