Impact of hydraulic retention time on phosphorus removal from wastewater using reactive media.

Phosphorus (P) discharge from wastewater treatment plants into the environment contributes to eutrophication issues. Reactive media filters represent an effective, simple and cost-effective solution to decrease the P content. Previous research used various experimental designs and often synthetic wastewater, making assessment of real-world performance difficult. This study assesses the impact of the hydraulic retention time (HRT) on P removal using real wastewater to refine design criteria for full-scale installations. Four media were compared in column experiments for >200 days. Different HRTs were applied and initially the media achieved low P effluent concentrations of >0.1 mg/L PO4-P, increasing over time. Best P removal was observed for the highest HRT with on average >99%. HRT was seen to be the driving factor for P removal rather than media capacity. Three of the four materials showed pH levels above 12 initially, decreasing over time. Water quality parameters, including organics, solids and metals, were monitored. In-depth analysis confirmed formation of calcium phosphate precipitation on the media's surface. The results suggest the importance of an optimal HRT to achieve high P removal and show that the reactive media application is an appropriate technology for P removal on small sites if the elevated pH is addressed.

Frequency of latent equine herpesvirus type-1 infection among a sample of horses in the central North Island of New Zealand.

Aim: To estimate the frequency of infection with equine herpesvirus type-1 (EHV-1) among horses from the central North Island of New Zealand, including the frequency of detection of the D752 genotype.Methods: Samples of retropharyngeal lymph nodes (RLN) and submandibular lymph nodes (SLN) were dissected from the heads of 63 horses that were humanely killed for various unrelated reasons between March and November 2015. DNA extracted from these tissues was subjected to enrichment for EHV-1 sequences by hybridisation with biotin-labelled EHV-1 specific probe, followed by recovery of EHV-1 sequences on streptavidin-coated magnetic beads. Enriched samples were tested for the presence of EHV-1 using nested quantitative real-time PCR. The EHV-1 amplicons were sequenced to determine the genotype of the virus.Results: The median age of the horses was 6 (min 2, max 30) years, and 47/63 (75%) were Thoroughbreds. EHV-1 DNA was detected in RLN samples from 6/63 (10%) horses, and three of these horses were also positive for EHV-1 DNA in SLN. The remaining horses were negative for EHV-1 DNA in both RLN and SLN samples. The N752 genotype was detected in all positive samples and the D752 genotype was not detected in any of the samples.Conclusions: EHV-1 continues to circulate among horses in New Zealand. The frequency of latent EHV-1 infection among sampled horses may have been underestimated due to the sensitivity limit of the assay or because of the limited anatomical sites sampled in the study. Lack of detection of the D752 genotype suggests that infection with this genotype is not common in horses in New Zealand.Clinical Relevance: If live animals are tested for EHV-1 using SLN biopsy it should be kept in mind that negative results do not rule out the presence of latent EHV-1 infection at other sites inaccessible for testing. The RLN appear to be the preferred sample for detection of EHV-1 DNA in horses following recent euthanasia.

Moving target: transient rotational stenosis precipitating jugular bow hunter's syndrome.

A 60-year-old man presented with a 10-month history of of stereotypical spells characterized by vertigo, tinnitus, blurred vision, left hemibody numbness, and occasional syncope, precipitated by turning his head leftwards. Cerebral angiography and CT angiography of the head and neck with provocative maneuvers did not demonstrate vertebral artery narrowing. However, there was narrowing of the left internal jugular vein due to extrinsic compression from the sternocleidomastoid with leftward head rotation in the setting of hypoplasia of the right internal jugular vein. The patient underwent a cervical venogram which confirmed the finding. Manometric evaluation demonstrated a gradient of 29 mm Hg across the stenosis with the head turned leftwards compared with 1 mm Hg in the neutral position. The patient was treated with myectomies of the left sternocleidomastoid, posterior belly of the digastric, stylohyoid and omohyoid and styloid process removal. Following surgery, the patient reported complete resolution of symptoms. Repeat venography demonstrated resolution of the stenosis and pressure gradient.

Moving target: transient rotational stenosis precipitating jugular bow hunter's syndrome.

A 60-year-old man presented with a 10-month history of of stereotypical spells characterized by vertigo, tinnitus, blurred vision, left hemibody numbness, and occasional syncope, precipitated by turning his head leftwards. Cerebral angiography and CT angiography of the head and neck with provocative maneuvers did not demonstrate vertebral artery narrowing. However, there was narrowing of the left internal jugular vein due to extrinsic compression from the sternocleidomastoid with leftward head rotation in the setting of hypoplasia of the right internal jugular vein. The patient underwent a cervical venogram which confirmed the finding. Manometric evaluation demonstrated a gradient of 29 mm Hg across the stenosis with the head turned leftwards compared with 1 mm Hg in the neutral position. The patient was treated with myectomies of the left sternocleidomastoid, posterior belly of the digastric, stylohyoid and omohyoid and styloid process removal. Following surgery, the patient reported complete resolution of symptoms. Repeat venography demonstrated resolution of the stenosis and pressure gradient.

Environmental & economic life cycle assessment of current & future sewage sludge to energy technologies.

The UK Water Industry currently generates approximately 800GWh pa of electrical energy from sewage sludge. Traditionally energy recovery from sewage sludge features Anaerobic Digestion (AD) with biogas utilisation in combined heat and power (CHP) systems. However, the industry is evolving and a number of developments that extract more energy from sludge are either being implemented or are nearing full scale demonstration. This study compared five technology configurations: 1 - conventional AD with CHP, 2 - Thermal Hydrolysis Process (THP) AD with CHP, 3 - THP AD with bio-methane grid injection, 4 - THP AD with CHP followed by drying of digested sludge for solid fuel production, 5 - THP AD followed by drying, pyrolysis of the digested sludge and use of the both the biogas and the pyrolysis gas in a CHP. The economic and environmental Life Cycle Assessment (LCA) found that both the post AD drying options performed well but the option used to create a solid fuel to displace coal (configuration 4) was the most sustainable solution economically and environmentally, closely followed by the pyrolysis configuration (5). Application of THP improves the financial and environmental performance compared with conventional AD. Producing bio-methane for grid injection (configuration 3) is attractive financially but has the worst environmental impact of all the scenarios, suggesting that the current UK financial incentive policy for bio-methane is not driving best environmental practice. It is clear that new and improving processes and technologies are enabling significant opportunities for further energy recovery from sludge; LCA provides tools for determining the best overall options for particular situations and allows innovation resources and investment to be focused accordingly.

The impact of intermediate thermal hydrolysis on the degradation kinetics of carbohydrates in sewage sludge.

The purpose of this paper is to report the results, from laboratory-scale investigations, on the impact of intermediate thermal hydrolysis process (ITHP) on already digested sludge in general, and sludge carbohydrate content degradation process efficiency in particular. The ITHP performance data were compared with the performance of established conventional thermal hydrolysis process (THP). The degradation of sludge carbohydrates as a result of thermal pre-treatment and anaerobic digestion followed the first order kinetics. The overall sludge organic matter degradation kinetics rate constants indicated that the use of THP as an intermediate digestion step can enhance the already digested sludge organic matter degradation; further reducing the sludge mass and increasing its conversion to biogas.

Evidence for absence of equine arteritis virus in the horse population of New Zealand.

AIM: To summarise investigation and laboratory data collected between 2001 and 2011 to provide evidence that equine arteritis virus is not present in the horse population of New Zealand. METHODS: Analysis was carried out on results from laboratory tests carried out at the Ministry for Primary Industries Animal Health Laboratory (AHL) for equine arteritis virus from horses tested prior to being imported or exported, testing of stallions as part of the New Zealand equine viral arteritis (EVA) control scheme and testing as part of transboundary animal disease (TAD) investigations for exclusion of EVA. Horse breeds were categorised as Thoroughbred, Standardbred or other. RESULTS: A total of 7,157 EVA serological test records (from import and export testing, EVA control scheme testing and TAD investigations) were available for analysis between 2005 and 2011. For the three breed categories a seroprevalence of ≤1.6% at the 95% confidence level was determined for each category. Between 2001 and 2011, as part of the EVA control scheme, the EVA status of 465 stallions was determined to be negative. During 2005-2011 EVA was excluded from 84 TAD investigations. CONCLUSIONS: There was no evidence of equine arteritis virus being present in the general horse population outside of carrier stallions managed under the EVA control scheme. CLINICAL RELEVANCE: Equine arteritis virus is absent from the general horse population of New Zealand.

Multifocal supratentorial diffuse glioma in a young patient with Ollier disease.

Ollier disease is a rare disorder characterised by the development of multiple enchondromas in long bones. Here we present a 19-year-old man with Ollier disease who also developed three synchronous brain tumours. Craniotomy, biopsy and debulking was performed for one lesion followed by a period of observation, and 9 months later he underwent a second craniotomy and debulking for symptomatic progression. Histopathological examination revealed a diagnosis of multifocal diffuse glioma (World Health Organization grade II). This report highlights the increased incidence of primary brain tumours in patients with Ollier disease and identifies the importance of screening patients with Ollier disease for primary neoplasms.

Prevalence and distribution of ocular onchocerciasis in three ecological zones in Nigeria.

The African Programme for Onchocerciasis Control (APOC) sponsored a baseline study in Nigeria between 1998 and 1999 on the prevalence and distribution of Onchocerciasis. The randomly selected 1,064 subjects in the baseline study underwent detailed eye examination in Cross River (rain forest), Taraba (savanna) and Kogi (forest-savanna) States. This paper compares and contrasts the public health significance of ocular onchocerciasis in these ecological zones. A blindness prevalence of 2.4% was recorded in the study, onchocerciasis being responsible for 30.2% of the bilaterally blind subjects. Onchocerciasis-induced blindness prevalence was relatively high in the rain forest and forest savanna zones of Cross River and Kogi States, Cross River having the highest site-specific prevalence (50.0%), followed by Kogi (41.7%). Taraba recorded only 27.3%. Other conditions identified included glaucoma, optic nerve disease and cataract rates of which were also found to be high among the population (6.9%, 6.5 % and 8.9% respectively). Anterior segment onchocercal lesions, punctate and sclerosing keratitis were the predominant features of the infection in the savanna zone (14.1% and 6.3% respectively), while posterior segment lesions were much more common in the forest zone. The need to sustain the present efforts to control onchocerciasis through mass ivermectin treatment is recommended.

Local recurrence of osteosarcoma after 17 years.

The recurrence of osteosarcoma is rare. Local recurrence occurs in 4-10% of patients following effective treatment. So far, recurrences as late as 15 years have been reported in the literature. We report a unique case of local recurrence of intramedullary osteosarcoma 17 years from initial diagnosis and treatment. Regular long-term follow-up of patients with this diagnosis is crucial to ensure early detection and treatment of potential recurrences.

Training to prevent golf injury.

Golf is a popular sport, with almost 30 million active participants in the United States each year. It is a leisure-time activity that satisfies the Surgeon General's recommendation for daily physical activity. Despite being a low-impact sport, 60% of professional and 40% of amateur golfers suffer from injury each season. One explanation for this high rate includes the repetitive bending and twisting of the swing. However, it is suspected that most golfers do not participate in any form of off-season training for their sport, nor do they warm up before exercise. This is especially important in the large number of retirees who have the time and resources to play golf. A basic review of golf swing biomechanics reveals significant torque stress on the shoulders, elbows, wrists, and lower back, which also corresponds to the most common areas of injury. Understanding the underlying mechanism makes it possible to design a sport-specific injury prevention program.

Inhibition, reactivation and aging kinetics of highly toxic organophosphorus compounds: pig versus minipig acetylcholinesterase.

Organophosphorus compound-based (OP) chemical warfare agents (nerve agents) represent a continuing threat to military forces and the civilian population. OPs act primarily by inhibiting acetylcholinesterase (AChE), the standard treatment for which includes AChE reactivators (oximes) in combination with antimuscarinic drugs. In the last decades, the efficacy of oximes has been investigated mostly in small animal models. In order to increase the predictive value of animal studies it is desirable to measure numerous physiological and biochemical parameters. This is difficult in small animals. Large animal models fulfil these requirements and swine are increasingly being used in toxicology studies. Swine breeds generally show considerable variability in different characteristics which may be minimised by the use of specially bred minipigs which have a known genetic background and health status. A comparative study was, therefore, initiated to investigate the kinetic properties of the White Landrace pig and Göttingen minipig AChE in respect of inhibition by the pesticide paraoxon; the nerve agents cyclosarin, VX and VR; the reactivation of inhibited AChE by oximes (obidoxime, pralidoxime and HI 6); and the aging and spontaneous reactivation of inhibited AChE. The determination of the respective kinetic constants found similarities between pig and minipig AChE which showed marked differences in comparison with human AChE values. This has to be considered in designing meaningful models for the investigation of oxime efficacy in pig or minipig experiments. The generated data indicate comparable kinetic properties of pig and minipig AChE and may provide a kinetic basis for extrapolation of data from pig studies to humans.

Evaluation of hybrid processes for nitrification by comparing MBBR/AS and IFAS configurations.

An integrated fixed-film activated sludge (IFAS) pilot plant and a moving bed biofilm reactor coupled with an activated sludge process (MBBR/AS) were operated under different temperatures, carbon loadings and solids retention times (SRTs). These two types of hybrid systems were compared, focusing on the nitrification capacity and the nitrifiers population of the media and suspended biomass alongside other process performances such as carbonaceous and total nitrogen (TN) removal rates. At high temperatures and loadings rates, both processes were fully nitrifying and achieved similarly high carbonaceous removal rates. However, under these conditions, the IFAS configuration performed better in terms of TN removal. Lower temperatures and carbon loadings led to lower carbonaceous removal rates for the MBBR/AS configuration, whereas the IFAS configuration was not affected. However, the nitrification capacity of the IFAS process decreased significantly under these conditions and the MBBR/AS process was more robust in terms of nitrification. Ammonia oxidising bacteria (AOB) and nitrite oxidising bacteria (NOB) population counts accurately reflected the changes in nitrification capacity. However, significantly less NOBs than AOBs were observed, without noticeable nitrite accumulation, suggesting that the characterisation method used was not as sensitive for NOBs and/or that the NOBs had a higher activity than the AOBs.

Mechanical sludge disintegration: providing an alternative carbon source for nutrient removal.

The primary driver for efficient biological nutrient removal (BNR) in activated sludge treatment is the sufficient supply of soluble carbon. Several methods have been proposed to increase available carbon sources and enhance BNR. This study examines the effect of ultrasonic equipment and mechanical disintegration technologies on surplus activated sludge (SAS), to release additional soluble chemical oxygen demand (SCOD) and volatile fattty acids (VFA), as a carbon food source for BNR. A laboratory sonicator with a maximum power of 550W, a 3KW SONIX radial horn and a deflaker declared to be used in the paper industry were investigated. All caused significant release of SCOD, up to 48 fold. The maximum concentration of VFA reached (from 0-1 mg 1(-1)), was 530 mg 1(-1). To assess the likely impact to BNR, batch (21) anaerobic lab tests examining the use of disintegrated sludge on phosphorus and nitrogen removal were completed. Phosphorus removal was estimated by observing the phosphate release under anaerobic conditions and up to 460% more release was observed relative to controls. In addition, denitrification rates were improved by over 106%. Ultrasonic and mechanical disintegration technologies have been shown to release soluble carbon for BNR, with subsequent laboratory nitrogen and phosphorus removal efficiencies observed to be comparable to acetate.

Mechanical sludge disintegration for the production of carbon source for biological nutrient removal.

The primary driver for a successful biological nutrient removal is the availability of suitable carbon source, mainly in the form of volatile fatty acids (VFA). Several methods have been examined to increase the amount of VFAs in wastewater. This study investigates the mechanism of mechanical disintegration of thickened surplus activated sludge by a deflaker technology for the production of organic matter. This equipment was able to increase the soluble carbon in terms of VFA and soluble chemical oxygen demand (SCOD) with the maximum concentration to be around 850 and 6530 mgl(-1), for VFA and SCOD, respectively. The particle size was reduced from 65.5 to 9.3 microm after 15 min of disintegration with the simultaneous release of proteins (1550 mgl(-1)) and carbohydrates (307 mgl(-1)) indicating floc disruption and breakage. High performance size exclusion chromatography investigated the disintegrated sludge and confirmed that the deflaker was able to destroy the flocs releasing polymeric substances that are typically found outside of cells. When long disintegration times were applied (>or=10 min or >or=9000 kJkg(-1)TS of specific energy) smaller molecular size materials were released to the liquid phase, which are considered to be found inside the cells indicating cell lysis.

Ammonium removal from solution using ion exchange on to MesoLite, an equilibrium study.

This paper investigates the potential of MesoLite ion exchange media for ammonium (NH(4)(+)) removal from solution in the presence of competing cations. Batch tests were performed under a range of conditions to assess the effect of contact time, solution pH and solution concentration on the performance and capacity of the media for this application. The data obtained was fitted to the Langmuir and Freundlich isotherm models with the Langmuir model providing the better description of the process. Results indicate a maximum equilibrium capacity of 49g NH(4)(+)Nkg(-1) of media is achievable under the experimental conditions studied. A detailed examination of the data shows that increasing solution concentration and increased contact time provide the best performance at an optimum pH of between 6 and 7.

Biomass effects on oxygen transfer in membrane bioreactors.

Ten biomass samples from both municipal and industrial pilot and full scale submerged membrane bioreactors (MBRs) with mixed liquor suspended solids concentrations (MLSS) ranging from 7.2 to 30.2g L(-1) were studied at six air-flow rates (0.7, 1.3, 2.3, 3, 4.4 and 6m(3)m(-3)h(-1)). Statistical analyses were applied to identify the relative impacts of the various bulk biomass characteristics on oxygen transfer. Of the biomass characteristics studied, only solids concentration (correlated with viscosity), the carbohydrate fraction of the EPS (EPS(c)) and the chemical oxygen demand (COD) concentration of the SMP (SMP(COD)) were found to affect the oxygen transfer parameters k(L)a(20) (the oxygen transfer coefficient) and alpha-factor. The relative influence on k(L)a(20) was MLSS>aeration>EPS(c)>SMP(COD) and on alpha-factor was MLSS>SMP(COD)>EPS(c)>aeration. Both k(L)a(20) and alpha-factor increased with increasing aeration and EPS(c) and decreased with increasing MLSS and SMP(COD). MLSS was found to be the main parameter controlling the oxygen transfer.

Ammonium removal from digested sludge liquors using ion exchange.

Liquors arising from the dewatering of digested sludge typically contain ammonium levels in the range 200-700mgl(-1) NH(4)(+)-N. These liquors are frequently recycled to the head of the wastewater treatment works (WwTW) untreated and can constitute >25% of the total nitrogen load entering the works at inlet. This paper investigates the use of a clay-based material, MesoLite, as an ion exchange medium for ammonium removal from recycle streams. Pilot-scale studies performed at Didcot WwTW, part of the Thames Water wastewater treatment network, indicate that MesoLite is highly selective for the ammonium ion. Results show that >95% of ammonium was removed from belt press liquors with an initial ammonium nitrogen concentration >600mgl(-1), with an overall ion exchange capacity >51g NH(4)(+)-Nkg(-1) medium and this resulted in an operating capacity in the range 27-36gNH(4)(+)-Nkg(-1).