Treatment of discontinuous emission of sewage sludge odours by a full scale biotrickling filter with an activated carbon polishing unit.

A SULPHUSTM biotrickling filter (BTF) and an ACTUSTM polishing activated carbon filter (ACF) were used at a wastewater treatment plant to treat 2,432 m3·h-1 of air extracted from sewage sludge processes. The project is part of Thames Water's strategy to reduce customer odour impact and, in this case, is designed to achieve a maximum discharge concentration of 1,000 ouE·m-3. The odour and hydrogen sulphide concentration in the input air was more influenced by the operation of the sludge holding tank mixers than by ambient temperature. Phosphorus was found to be limiting the performance of the BTF during peak conditions, hence requiring additional nutrient supply. Olfactometry and pollutant measurements demonstrated that during the high rate of change of intermittent odour concentrations the ACF was required to reach compliant stack values. The two stage unit outperformed design criteria, with 139 ouE·m-3 measured after 11 months of operation. At peak conditions and even at very low temperatures, the nutrient addition considerably increased the performance of the BTF, extending the time before activated carbon replacement over the one year design time. During baseline operation, the BTF achieved values between 266-1,647 ouE·m-3 even during a 6 day irrigation failure of the biofilm.

Anaerobic digestion of untreated and treated process water from the hydrothermal carbonisation of spent coffee grounds.

This study investigates the long-term performance of the mesophilic (35 °C) anaerobic mono-digestion of process waters (PW) from the hydrothermal carbonisation (HTC) of spent coffee grounds. At an organic loading rate (OLR) of 0.4 gCOD L-1 d-1, initial instability was seen, but after 40 days and supplementary alkalinity, the digestion stabilised with the chemical oxygen demand (COD) in the untreated PW degraded with 37.8-64.6% efficiency and the yield of methane at 0.16 L gCOD-1. An increase in OLR to 0.8 gCOD L-1 d-1 caused a collapse in biogas production, and resulted in severe instability in the reactor, characterised by falling pH and an increasing volatile fatty acid concentration. Comparatively, the digestion of a treated PW (concentrated in nanofiltration and reverse osmosis after removal of the fouling fraction), at OLR between 0.4 and 0.8 gCOD L-1 d-1, was stable over the entire 117 days of treated PW addition, yielded methane at 0.21 L gCOD-1 and the COD was degraded with an average efficiency of 93.5% - the highest efficiency the authors have seen for HTC PW. Further anaerobic digestion of untreated PW at an average OLR of 0.95 gCOD L-1 d-1 was stable for 38 days, with an average COD degradation of 69.6%, and methane production between 0.15 and 0.19 L gCOD-1. The digestion of treated PW produced significantly higher COD degradation and methane yield than untreated PW, which is likely to be related to the removal of refractory and inhibitory organic material in the post-HTC treatment by adsorption of hydrophobic material.

Adjuvant methotrexate escalated to toxicity for resectable stage III and IV squamous head and neck carcinomas--a prospective, randomized study.

To determine if adjuvant methotrexate (MTX), escalated weekly to toxicity, could improve disease-free survival (DFS) and overall survival by preventing recurrent disease, 60 patients with potentially resectable stage III or IV squamous head and neck carcinomas were stratified by primary site, stage, and nutritional status, then randomized by pairs to receive or not receive adjuvant MTX. All received standard surgery and postoperative radiation therapy. Five patients were taken off study because of unresectability at the time of surgery, leaving 55 evaluable patients. There were no statistically significant imbalances in known prognostic factors between the two treatment arms. MTX was begun at 40 mg/m2 and escalated 10 mg/m2 weekly (four doses preoperatively; four doses postoperatively, preradiation therapy; eight doses postradiation therapy) to mucosal or hematologic toxicity. The median peak MTX dose achieved was 80 mg/m2. Although three patients were hospitalized with MTX toxicity, none died of MTX toxicity. No patient receiving MTX had disease progression during treatment, and there was no increase in postoperative complications. Thirty-two patients died (median survival, 19 months); 23 patients are alive with median follow-up of 43 months. There was no statistically significant difference in actuarial DFS (P = 1.0) or overall survival (P = .61). Although patients on the MTX arm appeared to have less local and regional recurrences at first recurrence (thus more distant metastases), this did not reach statistical significance (P = .06). There was no significant difference between the sites of recurrence at death or last follow-up (P = .38).

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.

Viscosity changes in hyaluronic acid: irradiation and rheological studies.

Hyaluronic acid (HA) is a significant component of the extracellular matrix (ECM), particular interest being shown herein in synovial fluid. The present study aims to investigate the degrading effects of X-ray radiation on HA at radiotherapy doses. Measurements of viscosity and shear stresses on HA solutions have been made at different shear rates using various types of viscometer for different concentrations in the range 0.01-1% w/v of HA. The HA has been subjected to doses of 6 MV photon radiation ranging from 0 to 20 Gy, the major emphasis being on doses below 5 Gy. It is found that there is a dose-dependent relationship between viscosity and shear rate, viscosity reducing with radiation dose, this being related to polymer scissions via the action of radiation-induced free radicals. The dependency appears to become weaker at higher concentrations, possibly due to the contribution to viscosity from polymer entanglement becoming dominant over that from mean molecular weight. Present results, for HA solutions in the concentration range 0.01% to 1% w/v, show reduced viscosity with dose over the range 0-4 Gy, the latter covering the dose regime of interest in fractionated radiotherapy. The work also shows agreement with previous Raman microspectrometry findings by others, the possible bond alterations being defined by comparison with available published data.