The occurrence of pharmaceuticals in wastewater and the wider environment is of growing concern. This thesis focuses on anticancer drugs - a group of biologicallypotent and often recalcitrant set of chemicals whose fate and impact on the wider freshwater environment is poorly studied. The aims of this thesis were to prioritise a group of anticancer drugs for environmental monitoring programmes (from the many drugs in use), based on their consumption and fate during wastewater treatment; to undertake a national and regional survey of two commonly used anticancer drugs, cyclophosphamide (CP) and ifosfamide (IF) in wastewater and river water; to assess the performance of a river-based chemical fate model through comparisons with field observations; and to conduct a mass balance for CP in wastewater treatment plants to assess chemical fate during the different stages of wastewater treatment. Given the large number of anticancer drugs currently in use (>70) a decision support process was developed to ascertain a short list of drugs which are most likely to persist and be released with treated effluent to environmental waters. To do this, accurate consumption data were compiled from a hospital survey in NW England and combined with urinary excretion rates derived from clinical studies. Physical– chemical property data were then compiled along with likely chemical fate and persistence during and after wastewater treatment. A shortlist of 15 chemicals (from 65), including CP and IF, was prioritised based on their consumption, persistency and likelihood of occurrence in surface waters and supported by observational studies where possible. The ecological impact of these ‘prioritised’ chemicals however is uncertain as the measured concentrations in surface waters generally fall below standard toxicity thresholds, although there is evidence that exposure of aquatic organisms to some of these chemicals may induce low-dose genotoxic effects. This prioritised sub-list of anticancer drugs should prove useful for developing environmental screening programmes and targeted toxicity assays. To assess the occurrence of anticancer drugs in wasterwaters both CP and IF were measured in raw influent and final effluent waters from fourteen STPs located across England using a sensitive analytical method. CP was detected in both wastewater influent and effluent with mean (SD) concentration of 4.1 ng/L (4.8) and 6.6 ng/L (6.5), respectively, in agreement to measured ranges from a limited number of studies conducted in Europe and elsewhere. IF was only detected in four wastewater samples with the highest concentration being observed in wastewater effluent at 0.77 ng/L (cv = 24.3% (n=3)) and possibly reflecting the relatively lower consumption of this drug relative to CP. Additional monitoring was conducted in the rivers Calder, Darwen and Ribble (North West UK) with CP present at 5 of the 6 river locations with concentrations ranging from 0.41 to 3.71 ng/L. All these rivers receive treated wastewater effluent from sewage treatment works serving different population sizes, with CP measured in river water some ~20 miles downstream of the nearest STP, indicating the widespread dispersal and persistence of this chemical. CP and IF were measured systematically down the Rivers Aire and Calder in NE England and the results compared to a GIS-based water quality model (LF2000- WQX) used to predict CP and IF distributions in the two rivers, using regional consumption data and subsequent release quantities from STPs. CP was detected in 90% of river samples, apart from rural/uplands sites located at the source of the River Aire and Calder, respectively. CP presented the highest concentration, ranging from 0.17 to 4.53 ng/L (average 1.14 ng/L). IF was seldom detected in the sampled sites and concentrations ranged from < LOD to 1.82 ng/L (average 0.51 ng/L). Model results showed a fair agreement to the measured data for CP in the River Aire, discrepancies arise as the river progressed further downstream where the modelled data was lower than the measured data. A significant input of CP from Leeds STP at A7 (STP-1) saw the continuing rise in CP despite the increase in river flow. At the lower end of the Calder (pre-confluence with the River Aire) a spike in CP is detected far beyond the modelled value. A risk assessment was carried out to establish the potential adverse effects of anticancer drugs in the river catchment. All calculated risk quotients were below 1, showing no significant risk to aquatic organisms. However, long term toxicity studies for these chemicals are needed to define the environmental stress produced by their continuous exposure and induction. The fate and removal efficiency of cyclophosphamide (CP) and ifosfamide (IF) were investigated in two conventional sewage treatment plants (STP-S and STP-C) during different stages of waste water treatment. Overall average concentrations of CP were 1.17±1 ng/L in the two plants, which is lower than recent measurements conducted elsewhere. Grab-samples were coordinated with the hydraulic residence time of wastewater in each of the treatment stages in order to monitor changes in CP concentrations in the same parcel of water as it passed through the STP. Interestingly, concentrations of CP were observed to increase from raw influent to final tertiarytreated effluent and this is likely to be attributable to the degradation of a CPmetabolite and subsequent ‘liberation’ of the parent CP as the metabolite passes through the various sewage treatment processes. This observation, apparent in both studied STPs, has implications for chemical fate modelling of anti-cancer drugs, especially if STP influent loads are used to predict subsequent fluxes to receiving waters rather than final effluent values. Moreover, this increase in concentrations made a mass balance difficult to achieve, but highlighted that elimination/removal of CP in wastewater during primary to tertiary processing is very low (<20%). The calculated fluxes of CP with final effluent discharge were 3.16- 6.48 g/year for STP-S and 4.56 -51.57 g/year for STP-C and highlight that STPs are a continuing source of highly water-soluble, recalcitrant anticancer drugs to the environment.

While constructed wetlands (CWs) have been applied successfully to achieve contaminant removal from several types of wastewater, their efficiency and capacity is still low with respect to nutrients (nitrogen, N and phosphorus, P) removal. Through typical configurations, the removal efficiency for total nitrogen (TN) varied between 40 and 50% and total phosphorus (TP) between 40 and 60% depending on CWs type and inflow loading. This limits their implementation in delivering advanced wastewater treatment. Subsequently, the main aim of this study was to develop innovative CW processes to significantly enhance the nitrogen removal efficiency by investigating a new approach to the configuration of CWs and exploring substitutional operational strategies. If this is accomplished, it could make CWs a main wastewater treatment unit instead of conventional wastewater treatment systems. To accomplish this aim, two systems (multistage and single stage CW) were developed and comprehensively investigated and studied by applying a tidal flow operational strategy with gravel used as the main media for both systems. Tidal flow enhances and promotes the oxygen transfer to the CW system by batch pulse feeding and producing alternant wet/dry conditions of the CW media with wastewater. The multistage configuration is connected by four identical units in series and is divided into two phases depending on the seasonal temperature. The results of the multistage configuration showed average values for removal of 97.3%, 98.1%, 77.3% and 16.6% for chemical oxygen demand (COD), ammonium (NH₄⁺-N), TN and TP respectively for phase 1, and 87.5%, 78.5%, 60.3% and 10.2% for COD, NH₄⁺-N, TN and TP respectively for phase 2. However, TN removal was still not desirable with a mean removal efficiency in both phases 1 and 2, whereas the satisfactory removal for TN is >80%. This is due to the seasonal temperature and because all the stages were under aerobic conditions to a certain extent, which is unfavourable for denitrifying bacteria. Subsequently, to obtain a satisfactory efficiency of TN removal performance, the original multistage configuration system has been modified. To obtain a high and efficient TN removal performance for the multistage system, further investigations and developments have been made regarding system modification and alternative operational options. These have resulted in the development of improved nitrogen ABSTRACT iii removal processes by applying a step-feeding strategy to the system with different step-feeding schemes. As a result, 81.1% of TN removal was achieved. In addition, TP removal was poor because the system was not designed to removal phosphorus. The results of the single stage CW showed average values for removal of 86.7-99.3% and 64.1-74.8% for NH₄⁺-N and TN respectively, depending on the recirculation number (Rn) and inorganic carbon concentrations (IC); a single stage CW was used to follow the new route of nitrogen removal, called the Complete Autotrophic Nitrogen removal Over Nitrite (CANON) process. Microbial community analysis revealed that the dominant phyla for the multistage system were Proteobacteria, Planctomycetes, Firmicutes, and Bacteroidetes, whereas the dominant phyla for the single stage were Proteobacteria, Planctomycetes, Acidobacteria, and Chloroflexi. All these phyla were responsible for nitrogen and organic matter removal in both systems. The difference in microbial community and structure between both systems might attributed to the differences in the operational conditions. Overall, the results of this research study enhance the treatment capacity, which enables CWs to have the potential to work as the fundamental technology in advanced wastewater treatment and to increase our understanding of nitrogen removal in CW systems.

Three laboratory and pilot scale, diffused air activated sludge units were operated as continuous plug-flow tapered aeration systems at constant temperatures of 10 C, 20 C and 30 C. Dissolved oxygen was maintained at about 2 mg/l and the sludge was recycled at the same rate as the sewage feed rate for all the three units. Synthetic sewage was fed to each unit at four different detention periods namely 5, 3, 1.5 and 1 hour in turn including the return sludge. At each detention period the effect of four different concentrations of mixed liquor suspended solids of 2,000, 3,000, 4,000 and 5,000 mg/l were investigated. Operational parameters for each run measured included BOD 5 , COD, mixed liquor suspended solids, suspended solids, dissolved oxygen, turbidity, pH, free and saline ammonia, nitrite, nitrate, organic nitrogen, sludge volume index, sludge production, specific resistance to filtration of sludge, anionic surface active agent, air flow rates and total phosphates. In addition microscopic examination of the activated sludges vas,carried out occasionally. The results obtained indicated that BOD5 and COD removal efficiencies, air requirements, nitrification increase with an increase in temperature from 10 C to 30 C. Nitrogen loss is caused by aerobic denitr1fication. Complete removal of nitrogen in sewage is possible by aerobic nitr1fication-denitrif1cation process in the aeration tank of a single-stage activated sludge unit at 30 C and at high loading. Specific resistance to filtration of sludge, sludge production rate and phosphate removal decrease with an increase in temperature from 10 C to 30 C. The sludges· possess better resistance to bulking at higher temperatures and at low loadings. The average values of detergent removal efficiencies are well over 88% for all the three units at 1O C, 20 C and 30 C . Metazoa such as rotifers, earth worms and water mites were numerous at higher temperatures. There is only a marginal saving in cost for plant operating in tropical country as compared to that in developed country in spite of the better plant performance in tropical country.

It is estimated that 2.7 billion people worldwide are served by on-site sanitation facilities that require faecal sludge management. Anaerobic digestion is a treatment mechanism that can provide faecal sludge management, methane production and an effluent digestate rich in nutrients. However, there is a paucity of information regarding the composition of the input faecal sludge which hinders the advancement of anaerobic digestion treatment and downstream nutrient recovery together with a lack of knowledge as to how best to recover these output nutrients in a simple process. Following an initial review to collate composition data for fresh faeces and urine, practical studies examined the physical, biological and chemical composition and variation of four different types of faecal sludge from on-site sanitation facilities. Faecal sludge storage strongly influenced the biodegradability and methane production potential in subsequent anaerobic digestion. However, the high concentrations of ammonium observed in faecal sludge (520-1853 mg NH4-N L- 1 ) were highlighted as a key goal for nutrient recovery and the ability of biochar and clinoptilolite as natural adsorbents for ammonium recovery in a drying bed application were investigated through batch and dynamic studies using synthetic and real digestate. Batch tests observed ammonium uptake of 5 and 12.2 mg NH4-N/g for biochar and clinoptilolite respectively whilst under dynamic experimental conditions the most efficient operation for ammonium recovery was at the longest empty bed contact times (354 minutes), ensuring the maximum fertiliser value was obtained (60g NH4-N/kg clinoptilolite). Nevertheless, clogging occurred rapidly at the surface of the media bed (0.04 – 0.5 kg TS/m2 ), consequently a sacrificial sand layer (0.05 m) was included to increase the longevity of the nutrient recovery system (15 fold increase in TS application rates). It has been demonstrated that clinoptilolite can effectively be used as part of a sludge drying bed configuration to recover nutrients from digestate and the saturated media can be used directly as a fertiliser product or blended with the dried sludge to create a balanced nitrogen, phosphorus and potassium fertiliser product (5.9% NH4-N/ 4.2% P/ ≥6.0% K+ ).

The objective of the project was to develop a novel package plant using available process technologies that would be competitive in the domestic waste water treatment market. A market analysis identified the business opportunity for Balmoral Tanks to develop a package plant with higher treatment capability than its current product. A customer survey and a review of Regulatory standards provided valuable input into the design considerations for the package plant. A review of available process technologies and materials of construction resulted in the selection of a Moving Bed Biolm Reactor (MBBR) process and High Density Polyethylene material as the optimum design basis for the package plant. A detailed design exercise scoped out and specified all the components of the MBBR package plant. A four month duration programme for testing the prototype at Cranfield University facilities was devised which satisfactorily simulated typical domestic wastewater treatment operating conditions. Test rig problems associated with very low ambient temperatures were experienced in the early stages of testing and were identified and resolved. The prototype package plant unit subsequently operated satisfactorily and the performance was demonstrated to meet all the wastewater constituent removal design specifications. The MBBR process performance was shown to be consistent with published findings of other researchers. Novel fabrication methods developed by Balmoral Tanks resulted in the cost of the new MBBR package plant being only 3% higher than that of Balmoral Tanks current lower specification product. The new MBBR package plant is shown to be a potentially very marketable domestic wastewater treatment product.

The aim was to develop and subsequently evaluate a small package sewage treatment system that combined the commercial demands of the market with current and future environmental legislation in the UK. Questionnaires sent to key customers confirmed results from an initial literature review that non-process related features such as installation, plant price, aesthetic impact, maintenance requirement and operation have a similar impact on the final purchase decision than the achievable effluent quality. Conventional submerged aerated filter (SAF) technology was chosen for its simple operation over more advanced treatment technologies like sequencing batch reactors (SBR) and membrane bioreactors (MBR). The combination of SAF technology and jet aeration allowed the use of an exceptionally shallow tank structure. Two settlement stages for primary treatment and final clarification completed the new unitank design. Following successful clean water and field trials of a prototype unit, the new design was finalised, set-up for production and launched into the market. A second trial plant was permanently installed at a rural cottage in Cranfield, UK, with the objectives to validate and further improve the performance of the new design. Despite high variations in influent conditions, the trial unit produced a good effluent quality with average effluent BOD s , COD and SS levels of 16 mg rI, 100 mg rI and 30 mg rI respectively, thereby achieving overall removal efficiencies of 95.3%, 86.2% and 88.5% respectively. However, effluent ammonia nitrogen (~-N) levels were found to be inconsistent varying from as low as 9 mg rI to over 60 mg rI. Similar findings were revealed from other plants in the field serving domestic and non-domestic applications. The compact and exceptionally shallow tank structure combined with a competitive retail price met the commercial needs of the target market, which resulted in increased sales turnover and market share.

Investigations into nitrate leaching from sludge and sludge injection into grassland have been undertaken for many years, however phosphate leaching from soils and shallow injection of sludge into grassland are relatively new ideas. This lysimeter study sets out to investigate the influence of the type of slurry and application rate on the amount of phosphorus and nitrogen lost by leaching. The field trial assesses the influence of application methods on grass yield, sward damage and ritrogen loss by leaching through analysing the effects on a grass crop using two different methods of injection and comparing them with surface application and granular fertilizer. Losses of P from sandy loam soils were found to be minimal therefore contamination of groundwater is thought to be unlikely. Similar leacling patterns were observed from both the cake and liquid sludges at all four rates_ applied, however the liquid sludge released more phosphate than the cake sludge, resulting in higher concentrations recorded. The lysimeter study also found leaching losses of ritrate from both sludge types to be well above the EC maximum permissible level of 11.3 mg nitrate-N l`l at all four rates. Residual N from the previously cropped soil masked the nitrate concentrations during the initial stages of the study. Losses of N from the cake sludge was lower than from the liquid treated plots due to slow release. It was also found that environmental factors such as high temperatures and rainfall influence nitrate leaching. The field trial analysed various disposal methods in terms of nitrate leached, crop yield and sward damage. N losses from shallow injection were reduced compared to the deep injection plots, as the sludge was placed in closer proximity to the crop roots. Olibhe Collins, Silsoe College, 1996. In overall terms the shallow injection system yielded the greatest quantity compared to surface applied or the inorganic fertilizer. Damage caused by the tines during shallow injection was not evident compared to the deeper injection system where sward damage and dieback was considerable. The results from the field trial indicate that the shallow injection of sewage sludge has proved to the most environmentally friendly method for the disposal of sludge to farm land.

The literature relating to nitrification in wastewater treatment and bioaugmentation as a method to enhance wastewater treatment processes is reviewed. The use of a commercially available bioaugmentation product (based on a Nitrosomonas culture), which claimed to enhance nitrification in biological wastewater treatment was investigated. The product was tested in full scale trials, in shake flask experiments and its efficacy modelled using a simple activated sludge simulation. At full scale trickling filter plants a bioaugmentation product designed to enhance BOO removal was also tested. This product increased BOO removal by up to 7% in the recovery period following low temperature. The Nitrosomonas culture improved percentage ammonia removal by nearly 10% in trickling filters even at low temperatures of 6.5°C. A maximum improvement of 20% occurred at one trickling filter site at higher temperatures. At activated sludge sites the Njtrosomonas culture improved the nitrifying ability of the activated sludge, as assessed by the laboratory standard method, and at one site noticeably improved percentage ammonia removal during periods of high dosing. At one site the maximum improvement was an increase of 22% in percentage ammonia removal during high dosing. However the operational parameters, loads, hydraulic retention time, mixed liquor suspended solids, sludge age and temperature had a great effect on nitrification. If better process control was applied at one of the works the plant would have had little trouble nitrifying i.e. lower loads, higher HRT, MLSS and sludge age during low temperatures. Sludge wastage regimes contributed greatly to the failure to nitrify. It was found that the activity of the Nitrosomonas culture increased with temperature and acclimatisation and decreased on inoculation into activated sludge. The product facilitated nitrification when inoculated into non-nitrifying activated sludge. Ammonia removal increased with size of inoculum. The simple dynamic model described showed the development of a Njtrosomonas population from inoculation with the Nitrosomonas culture. The model showed that the effectiveness of a bioaugmentation product in activated sludge would depend on the amount of nitrifiers returned to the aeration basin more than other operational factors. The model predicted full nitrification at one of the full scale sites within three days. Bioaugmentation did enhance nitrification at full scale works. However, dosage rates required for improvement meant that conventional methods such as better process control or retrofitting would be economically more feasible.

Sewer systems are designed and installed to convey stormwater and wastewater from areas where it is collected to a treatment works or a suitable discharge point into a natural watercourse. Over time, however, changes in climate, population growth and urbanisation increase the flows these sewer systems need to convey. This thesis discusses a method, and developed assessment framework, to propose solutions to address flood risk. The method involves iteratively simulating a sewer system and designing vortex flow controls and orifice plates into the sewer system. These passive flow controls are designed into the sewer system, whilst accounting for sub-catchment flood vulnerability scores, to attenuate potential flood volumes and make use of available storage capacities in the upstream sections of the sewer system. The flow control positioning method uses the SWMM 5 program to simulate the sewer system, a developed hyetograph generator for the rainfall inputs and a flow control design tool. The whole assessment framework was programmed in Microsoft Excel and VBA. Vortex flow controls and orifice plates were chosen as they require no power, have no moving parts and are self-activating. Vortex flow controls are primarily designed into the sewer system, over orifice plates, due to their higher mean flow-rate and reduced blockage risk due to the larger outlet diameters. Four sewer system models were used to demonstrate the application of the assessment framework, in which one model was hypothetical and three were anonymised. The smallest model consisted of 14 nodes and collected surface runoff from 1.5 hectares. The largest model consisted of over 280 nodes and was a combined sewer system from a town in the South-East of England. In the application of the assessment framework, it was shown that strategically positioning and designing passive flow controls into the sewer system can have a beneficial effect by reducing flood risk. In one case study, the flood resistance level of a sewer system was increased from a 1 in 3 year return period to a 1 in 108 year return period. In the largest case study, which was of a combined sewer system, the flood resistance level was increased from a 1 in 1 year return period to a 1 in 71 year return period. The results of the analyses also found that installing vortex flow controls, instead of orifice plates only, tended to achieve a greater increase in the flood resistance level. Comparison of the proposed solutions from the method to alternative flood alleviation methods shows that the strategic positioning of passive flow controls to be a competitive and feasible solution to reduce flood risk.

Anaerobic batch reactors were inoculated with cold-adapted biomass (seed) to treat the organic material (COD) of domestic wastewater at 4, 8 & 15°C. The substrate was pre-UV sterilized to preclude competition between the cells thriving in the seed and the autochthonous, originated from wastewater cells. The performance in terms of organic removal showed that the specific cold-adapted inoculum efficiently treats anaerobically raw domestic wastewater at all temperatures based on the UWWTD (Urban Waste Water Treatment Directive) (91/271/EEC). The observed methanogenic taxa were Methanomicrobiales, Methanosaetaceae, and Methanosarcina during the whole experimentation. Methanomicrobiales were predominant at lower temperatures (4, 8°C) followed by Methanosaetaceae; at 15°C there was no distinct difference amongst them. Longer enrichment showed that further investigation may be required to clearly point the predominance between methanogens. Specific cellular activity was calculated (via qPCR, FISH) to enable scale-up & design simulation. The specific methanogenesis values showed that the activities at low temperatures are at least similar to those of typical mesophiles using a conservative cellular weighing reference to convert the cells to VSS. Higher specific activities were observed after acclimation of the cells at 4°C compared to 15°C regardless of the operational temperature (4 or 15°C). Acclimation at 4°C also resulted in a formation of a community that can be hardly disturbed from the competition of the wastewater cells when the seed:substrate ratio is low. This was not evident after acclimation at 15°C and it manifests that anaerobic treatment start-up at 4°C results in a sturdy and highly active methanogenic community. The CODRAW:CH4 conversion at 4°C was approximately 50% and reached up to 80% of the theoretically expected for sterile and non-sterile wastewater feed respectively. It is likely that the conversion was boosted from the synergy of the indigenous bacterial communities from wastewater and the cells originated from the seed. Enzymes (lipases) assays showed that the wastewater-originated group of cells (bacteria) contributed to the hydrolysis of insoluble organic material (lipids) and led to richer formation of intermediates that were subsequently utilized by the methanogenic populations of the seed. Limited lipid hydrolysis accounted for the organic material that remained insoluble. The lipases assays demonstrated that on equal temperatures (37°C) the specific activity of the enzymes secreted from the cells at low temperature (4°C) is higher than those secreted from cells at 15°C. This proves that the formation of a sturdier and of higher wastewater treatment performance community is likely when this is developed at low temperatures. The assay also demonstrated that a 4-degree temperature increase (from 4-8°C) is adequate to trigger the lipid:CH4 bio-conversion. Thus, for a complete anaerobic wastewater treatment using the specific inoculum, the temperature limit lies in-between 4°C and 8°C. A scale up designation based on the differentiation of the specific methanogenic activity according to temperature shouted that this limit lies at 5°C. For operation at lower temperature (<5°C), the required vessel volume and the hydraulic retention time (HRT) become extremely high and consequently financially unattainable. The results suggest that inoculating digesters for low temperature operation with cold-adapted communities is a promising way to treat wastewater and an appropriate solution for the investigation of the process limits. Hence, my recommendation for successful low temperature carbon neutral wastewater treatment is the inoculation of anaerobic reactors with cold adapted or psychrophilic biomass strategy, acclimation at low temperature and operation at a temperature >5°C.