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The potential of smart cities in remediating environmental problems in general and waste management, in particular, is an important question that needs to be investigated in academic research. Built on an integrative review of the literature, this study offers insights into the potential of smart cities and connected communities in facilitating waste management efforts. Shortcomings of existing waste management practices are highlighted and a conceptual framework for a centralized waste management system is proposed, where three interconnected elements are discussed: (1) an infrastructure for proper collection of product lifecycle data to facilitate full visibility throughout the entire lifespan of a product, (2) a set of new business models relied on product lifecycle data to prevent waste generation, and (3) an intelligent sensor-based infrastructure for proper upstream waste separation and on-time collection. The proposed framework highlights the value of product lifecycle data in reducing waste and enhancing waste recovery and the need for connecting waste management practices to the whole product life-cycle. An example of the use of tracking and data sharing technologies for investigating the waste management issues has been discussed. Finally, the success factors for implementing the proposed framework and some thoughts on future research directions have been discussed.

The recovery and utilization of recovered paper have increased over past decades all over the world due to economic, environmental, and social issues. However, it is well known that an extended recovered paper collection is detrimental to its quality, either by the exploitation of lower quality sources such as households, or the spreading of commingled systems instead of selective collection systems. The influence of these two factors was assessed by analyzing the quality of different recovered paper grades used as raw material in a mill located in Madrid (Spain) producing newsprint and light weight coated paper from recovered paper. Part 1 of the paper deals with the impact of increased collection rates on the quality of recovered paper and Part 2 with the use of commingled collection systems. Results of Part 1 show that increased collection rates have a large impact on the quality of the recovered paper. The quality, measured as total unusable material and moisture contents, had deteriorated very rapidly in only four years (2005-2008) as a consequence of increased collection rates. Collection rates increased in Spain from 58.5% to 68.6% during this period, resulting in more than 50% increase of total unusable material and 25% of moisture content. The downgrading of the quality of recovered paper is one of the major threats for extending the current limits of paper recycling. Therefore, future challenge is to increase its availability but maintaining its quality.

This paper is included in the Proceedings of the 16th Greenhouse Gas Control Technologies Conference (GHGT-16), organised 23-27 October 2022 in Lyon, France. It provides an overall summary of the contents of the EU-funded H2020 ACCSESS project

In this work, the presence of 20 pharmaceuticals in wastewater from Colombia is investigated. Several widely consumed compounds have been detected in wastewater samples from different origins and geographical areas in Colombia. The studied pharmaceuticals included antibiotics, analgesics and anti-inflammatories, cholesterol lowering statin drugs, lipid regulators, and anti-depressants. The investigated samples were urban wastewater collected during one whole week before (influent) and after treatment (effluent) in the wastewater treatment plants (WWTPs) of Bogotá and Medellin. Raw wastewater from the Hospital of Tumaco and from the city of Florencia were also collected. Analyses performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed that most of the target analytes were present in all the wastewater samples. The highest concentrations (up to 50 μg/L) corresponded to acetaminophen, but several antibiotics, such as azithromycin, ciprofloxacin and norfloxacin, and antihypertensive drugs, such as losartan and valsartan, were commonly present in influent wastewater (IWW) at levels above 1 μg/L. Moreover, the treatment applied in WWTPs seemed to not efficiently remove the compounds under study, because most pharmaceuticals were also present in effluent wastewater (EWW) at concentrations close to those of the IWW. Special emphasis was made in this work on the quality of data reported, performing a detailed study of quality control (QC) samples. The analytical approach used –direct injection of 5-fold diluted samples without any additional treatment – is simpler and faster than the commonly applied solid phase extraction (SPE). The use of 12 isotope-labelled internal standards ensured the satisfactory correction of matrix effects for the corresponding analytes. For the remaining 8 compounds, no drastic matrix effects were observed, and only four compounds (cloxacillin, doxycycline, losartan, tetracycline) presented QC recoveries near or slightly below 60%, revealing ionization suppression, particularly in the IWW. Data on the occurrence of pharmaceuticals reported in this paper are the basis for current studies that aim to develop efficient systems for the degradation/removal of these compounds from the aquatic environment. COL0111863 COL0125116

Highlights • Socio-demographic risk factors were sex, financial constraints and employment status. • Behaviour factors associated were being a non-drinker, problem drinking and smoking. • Psycho-social factors were not having enough people to confide in and life events. • Large effect size and dose-response for financial constraints, problem drinking and life events. • Employment status was more strongly related to depressive symptoms in men than women., Background Russia has a high burden of suicide and alcohol-attributable mortality. However there have been few studies of the epidemiology of depression. Methods The study population was 5077 men and women aged 35-69 years from a cross-sectional population based survey in the cities of Arkhangelsk and Novosibirsk (2015-17). Moderate depression was defined as Patient Health Questionnaire-9 (PHQ-9) score≥10. Risk factors considered were socio-demographic factors (age, sex, marital status, living alone, education, employment status, financial constraints); health behaviours (smoking, alcohol use) and psycho-social factors (life events and social support). Results After mutual adjustment for all other factors, there was evidence that PHQ-9≥10 was associated with sex (higher in women), financial constraints, employment status, being a non-drinker, problem drinking, smoking, not having enough people to confide in and the number of life events in the past 6 months. Employment status was more strongly associated in men (OR 1.84 (95%CI 1.17, 2.88)) than women (OR 1.15 95% CI 0.86, 1.55). The effect size was particularly striking for financial constraints (odd ratio over 3 times higher in those with not enough money for food and clothes compared to no financial constraints), problem drinking (OR 1.72 (1.12, 2.65) among drinkers with CAGE score of 2 and 2.25 (95% CI 1.42, 3.57) in those with score ≥3 compared to zero) and life events (85% higher odds in those experiencing one life event and over 4 times higher odds in those experiencing 3 or more life events) all of which demonstrated a dose-response with PHQ-9>=10. Limitations The study was cross-sectional in nature therefore temporal relationships could not be assessed. Conclusions We have identified here a range of risk factors for depression among the Russian general population consistent with findings from other populations. The strikingly strong association with financial constraints indicates the importance of social inequality for the burden of depression.

Coronavirus disease 2019 (COVID-19) has harshly impacted Italy since its arrival in February 2020. In particular, provinces in Italy's Central and Northern macroregions have dealt with disproportionately greater case prevalence and mortality rates than those in the South. In this paper, we compare the morbidity and mortality dynamics of 16th and 17th century Plague outbreaks with those of the ongoing COVID-19 pandemic across Italian regions. We also include data on infectious respiratory diseases which are presently endemic to Italy in order to analyze the regional differences between epidemic and endemic disease. A Growth Curve Analysis allowed for the estimation of time-related intercepts and slopes across the 16th and 17th centuries. Those statistical parameters were later incorporated as criterion variables in multiple General Linear Models. These statistical examinations determined that the Northern macroregion had a higher intercept than the Southern macroregion. This indicated that provinces located in Northern Italy had historically experienced higher plague mortalities than Southern polities. The analyses also revealed that this geographical differential in morbidity and mortality persists to this day, as the Northern macroregion has experienced a substantially higher COVID-19 mortality than the Southern macroregion. These results are consistent with previously published analyses. The only other stable and significant predictor of epidemic disease mortality was foreign urban potential, a measure of the degree of interconnectedness between 16th and 17th century Italian cities. Foreign urban potential was negatively associated with plague slope and positively associated with plague intercept, COVID-19 mortality, GDP per capita, and immigration per capita. Its substantial contribution in predicting both past and present outcomes provides a temporal continuity not seen in any other measure tested here. Overall, this study provides compelling evidence that temporally stable geographical factors, impacting both historical and current foreign pathogen spread above and beyond other hypothesized predictors, underlie the disproportionate impact COVID-19 has had throughout Central and Northern Italian provinces.

This study aims to enhance nitrogen removal efficiency of a moving bed biofilm reactor (MBBR) by developing a new MBBR with zeolite powder-based polyurethane sponges as biocarriers (Z-MBBR). Results indicated the total nitrogen (TN) removal efficiency and simultaneous nitrification and denitrification (SND) performance in Z-MBBR were nearly 10% higher than those in the conventional MBBR with sponges as biocarriers (S-MBBR). About 84.2 ± 4.8% of TN was removed in Z-MBBR compared to 75.1 ± 6.8% in S-MBBR. Correspondingly, the SND performance in Z-MBBR and S-MBBR was 90.7 ± 4.1% and 81.7 ± 6.5%, respectively. The amount of biofilm attached to new biocarriers (0.470 ± 0.131 g/g carrier) was 1.3 times more than that of sponge carriers (0.355 ± 0.099 g/g carrier). Based on the microelectrode measurements and microbial community analysis, more denitrifying bacteria existed in the Z-MBBR system, and this can improve the SND performance. Consequently, this new Z-MBBR can be a promising option for a hybrid treatment system to better nitrogen removal from wastewater.

Disinfection of combined sewer overflow (CSO) is necessary to reduce the amount of microorganisms discharged into surface waters. In this study, an efficient and cost-competitive treatment for CSO, employing UV disinfection, was developed. High suspended solids content in CSO poses a significant challenge for UV disinfection so laboratory experiments were carried out to asses the effect of chemical pre-treatment followed by micro-sieve filtration on the reduction of total suspended solids (TSS) and the increase of UV transmittance (UVT). The efficiency of UV, with and without pre-treatment, was investigated and a microbial inactivation model was developed to describe the fecal coliforms (FC) inactivation kinetics. Finally, the environmental impacts of the proposed treatment were simulated at the large-scale by stormwater management model (SWMM), and the cost of the proposed treatment train was evaluated and compared with current CSO treatment strategies. Experimental results showed that UV alone achieved 3.6-log reduction of FC at a UV fluence of 80 mJ/cm2, while a 4-log reduction of FC was achieved at a much lower UV fluence of 10 mJ/cm2, when the UV disinfection was preceded by chemical pre-treatment and microsieving filtration using a 32 μm mesh. Under these conditions, the TSS removal achieved was 73%, and the UVT increased from 14% to 32%.The SWMM showed that the proposed CSO treatment achieved a reduction in TSS by one order of magnitude and a decrease in number of FC from 1.05 × 1014 to 1.24 × 1010 CFU. The cost analysis performed herein suggests that the proposed treatment train is competitive to current CSO treatment strategies in terms of cost-effectiveness. The study demonstrates the potential of the innovative CSO treatment scheme to quickly and effectively treat a large amount of wastewater flow thus providing municipalities with a low footprint treatment unit for CSO.

Background Obesity threatens to undo the improvements that have been made in life expectancy over the last two centuries. It disproportionately affects lower socioeconomic and ethnic minority groups and has become one of the most important global health challenges of the 21stcentury. Whilst obesity is not confined to city populations, cities are home to more than half of the world's population with concentrated groups at high risk of obesity. Cities have also long been the forefront of social and technological change that has led to our current obesogenic environment. The aim of this study was to systematically identify city-wide interventions to address obesity, from which recommendations for policy makers, health system leaders and political leaders in cities could be made. Methods Systematic review, conducted according to PRISMA guidelines, examining Embase, Ovid Medline, Central, Scopus, Campbell Library, CINALH, Health Business Elite; Health Management Information Consortium (HMIC), PyschINFO and Prospero. No restrictions on article type, date range or geographic location were applied. Along with classic academic sources, books and policy white papers were sought and reviewed. Studies that described a city-wide intervention to reduce obesity were included, irrespective of study design or perceived methodological quality. Only studies in English language were included. The primary outcome indicators that were sought and extracted were: reduction in obesity, reduction in weight and/or reduction in BMI. Where a primary outcome indicator was not stated, any other secondary impact measure was identified and recorded. This manuscript represents thematic analysis of a sub-set of data from the Prospero study, registration number: CRD42020166210 Findings Our search yielded 42,137 original citations of which 1614 met the inclusion criteria and 96 were coded as relating to obesity. The 96 citations, ranging in year of publication 1997 to 2019, were conducted in 36 cities, with 13 citations either not stating a city or covering multiple cities, across 5 continents. The highest proportion of publications were from North America (59 / 96) and in particular the USA (56/96) and New York City (23/96). Primary outcome indicators were only stated in one quarter of the identified studies (24/96). Overall, there was heterogeneity of study design, descriptive methodologies and publication types, with a majority being descriptive texts using qualitative instruments of assessment. Interpretation Multi-level and multi-component interventions, at the individual, community and city level, done in concert, are needed to address obesity. A composite of interventions that cities can utilise to address obesity is provided. These interventions will also be beneficial to the environment and make the case that personal health and planetary health are inextricably linked and should be considered as one. Funding None

Microalgae biotechnology is a promising tool for many applications, including the elimination of nutrients and other contaminants from wastewater. In this work, we measured the removal efficiency of two wastewater treatment processes: an activated-sludge based conventional process and another based on microalgae biotechnology using high-rate algae ponds (HRAPs). The latter was tested using two different configurations. In the first one, HRAPs were placed after an UASB reactor and used as a tertiary treatment to remove nutrients. In the second, the UASB reactor was disconnected so the HRAPs were directly fed with pretreated wastewater. Additional treatment was performed using dissolved air flotation (DAF). The performances of both configurations (UASB-HRAP and HRAP-DAF) were compared to that of the conventional line including primary and secondary biological treatments and operating in parallel within the same wastewater treatment plant (WWTP). Sixty-four out of 81 target PhACs were detected in the influent of the WWTP, at an average concentration of 223 μg L−1, whereas 55 and 54 were measured in the conventional (14 μg L−1) and non-conventional (17 μg L−1) effluents. Average removal efficiencies were similar (94 vs. 92%) for both treatment lines when comparing total PhACs concentrations. The compositional patterns of the resulting effluents, however, were not, suggesting the occurrence of differential removal mechanisms depending on the chemicals and wastewater treatments considered. Highly consumed compounds such as ibuprofen and acetaminophen were predominant in the non-conventional effluent (>1 μg L−1), denoting lower removal than in the conventional line. On the other hand, elimination of diclofenac and some specific antibiotics and diuretics (e.g., hydrochlorothiazide) was between 15 and 50% higher using HRAPs. Overall, the efficiency of the microalgae technology removing PhACs was found to be comparable to that used in conventional WWTPs. This, combined with a higher efficiency removing nutrients, shows the potential of HRAP technology for wastewater treatment as an alternative (or addition as tertiary treatment) to more conventional approaches based on activated sludge.

Iron-based chemically enhanced primary sedimentation (CEPS) is increasingly adopted for wastewater treatment in mega cities, producing a large amount of sludge (Fe-sludge) with a high content of organics for potential organic resource recovery. In this experimental study, acidogenic fermentation was applied treat FeCl3-based CEPS sludge for production of volatile fatty acids (VFAs) at different pHs. Batch fermentation tests on the Fe-sludge with an organic content of 10 g-COD/L showed that the maximum VFAs production reached 2782.2 mg-COD/L in the reactor without pH control, and it reached 688.4, 3095.3, and 2603.7 mg-COD/L in reactors with pHs kept at 5.0, 6.0 and 8.0, respectively. Analysis of the acidogenesis kinetics and enzymatic activity indicated that the alkaline pH could accelerate the rate of organic hydrolysis but inhibited the further organic conversion to VFAs. In semi-continuous sludge fermentation tests, the VFAs yield in the pH6 reactor was 20% higher than that in the control reactor without pH regulation, while the VFAs yield in the pH8 reactor was 10% lower than the control. Illumina MiSeq sequencing revealed that key functional microorganisms known for effective sludge fermentation, including Bacteroidia and Erysipelotrichi, were enriched in the pH6 reactor with an enhanced VFAs production, while Clostridia became more abundant in the pH8 reactor to stand the unfavorable pH condition. The research presented acidogenic fermentation as an effective process for CEPS sludge treatment and organic resource recovery and provided the first insight into the related microbial community dynamics.

There are a lot of coal cinder and dust in the development of coal resource-based cities. Improper handling will cause dust flying, which has a great impact on urban residents and the environment. The purpose of this research is to follow the principle of waste recycling, to use waste shrimp shells to extract chitosan as a raw material, to carry out graft polymerization with acrylic acid and polyvinyl alcohol-1788, and to carry out amidation crosslinking reactions with ethylenediamine tetraacetic acid to produce products. The results showed that the degree of deacetylation of chitosan reached 85% with the optimized extraction method, which greatly shortened the process cycle. Through orthogonal experiments and osmotic wetting experiments, the best preparation process was determined. The reaction process, structure of the product and adhesive structure of the solidified layer were analyzed by FTIR, XPS and SEM. The thermal stability of the product was analyzed by thermogravimetry. Relevant performance tests showed that the product had good adhesion with dust, the hardness of the solidified layer could reach 98 HA, and the dust fixation rate was 92.67% when the wind speed was 15–18 m/s. It has the advantage of circulating dust fixation, which improves the utilization rate of resources.

Combined sewer overflows contain a highly variable, wide range of contaminants, both in particulate and soluble form, making conventional water treatment processes unable to offer adequate public health protection. In this study, an integrated treatment process designed to simultaneously remove typical combined sewer overflow pollutants (suspended solids, chemical oxygen depends, turbidity) in conjunction with nutrient (nitrogen and phosphorus), was developed. The removal of particulates as well as dissolved nitrogen and phosphorus was achieved by first adsorbing soluble pollutants on zeolite and powdered activated carbon, and subsequently applying filtration carried out by polymer-enhanced microsieving. Laboratory experiments were designed using design-of-experiment techniques and carried out to assess the effects of the various treatment variables (cationic polymer, zeolite, powder activated carbon and microsieve size) in the designed combinations. A response surface model was fitted to the experimental dataset in order to capture and describe the non-linear relationships between treatment variables and treatment objectives. Finally, an optimization study was carried out using Pareto analysis showing that cationic polymer, zeolite, and powdered activated carbon, followed by fine mesh microsieving, worked synergistically in the integrated treatment process. Several optimal process conditions emerged, in particular, a treatment combination consisting of 1.1 mg/L of the cationic polymer, 250 mg/L of zeolite, 5 mg/L of powdered activated carbon, and a 370 μm mesh size. Under this condition, expected performance would be reductions of 72%, 56%, 35%, and 75% for turbidity, total Kjeldahl nitrogen, total chemical oxygen demand, and total phosphorous, respectively. The findings presented in this paper demonstrate the possibility of achieving multiple treatment objectives in a single and integrated treatment step, hence providing municipalities with viable treatment options where the issues of combined sewer overflow and nutrient management are simultaneously tackled.

The effect of alcohol ethoxylates on the treatment of municipal wastewater by a submerged anaerobic membrane bioreactor was investigated by a 400days operation including the treatment efficiency, methanogenic activity of sludge and microbial community structure. The results indicated that alcohol ethoxylates (5.0-200mg/L) was efficiently degraded and converted into methane due to the similar COD removal 95.5-98.8% and rising biogas production rate (2.30-4.25L/d) compared with control (96.8% and 2.55L/d). The microbes in sludge could copy with the presence of alcohol ethoxylates in wastewater by releasing more SMP and EPS, which caused a higher membrane fouling rate. Moreover, via long term acclimation, the specific methanogenic activity of sludge was greatly enhanced due to the changes of microbial community structure. Hence, the sludge self-acclimation to alcohol ethoxylates was responsible to the efficient methane recovery in treatment of municipal wastewater.

In many nations industrial scale AD of non-agricultural waste materials (such as MSW) has not yet reached its full potential, often constrained by the lack of secure, inexpensive, high quality AD feedstocks, and markets for the resulting digestate material. We tested the output material of a high throughput novel industrial process to define its potential as an AD feedstock (based on quality and consistency). This process, designed to circumvent the constraints of source segregation while still generating segregated waste streams, resulted in the production of a temporally homogenous fibrous material with: an average moisture content of 44.2 (±2.33)%; C:N ratio of ∼32.9:1 (±3.46:1), C:P ratio of ∼228:1 and gross calorific value of 17.4 (±0.29) MJ/kg(DM). This material provided a CH4 yield of between 201 and 297 m3 CH4/tonne(DM) (271–401 m3 CH4/tonne(vs)) comparable to commonly used AD feedstocks. Material contaminant levels were temporally consistent (P > 0.05), (average values being Cd 0.63 (±0.19), Cu 56.3 (±7.45), Crtot 51.4 (±4.41), Hg < 0.3, Ni 28.9 (±5.17), Pb 79.2 (±23.71), Zn 202 (±44.5), total polyaromatic hydrocarbons (PAH) 2.2 (±0.3), and total polychlorinated biphenyls (PCB) (

The thin-layer drying behavior of the municipal sewage sludge in a laboratory-scale hot air forced convective dryer assisted with air-borne ultrasound was investigated in between 70 and 130 °C hot air temperatures. The drying kinetics in the convective process alone were compared to that for ultrasound-assist process at three ultrasound powers (30, 90, 150 W). The average drying rates within whole drying temperature range at ultrasound powers of 30, 90 and 150 W increased by about 22.6%, 27.8% and 32.2% compared with the convective drying alone (without ultrasound). As the temperature increasing from 70 °C to 130 °C, there were maximum increasing ratios for the effective moisture diffusivities of the sewage sludge in both falling rate periods at ultrasonic power of 30 W in comparison with other two high powers. In between the ultrasound powers of 0 and 30 W, the effect of the power on the drying rate was significant, while its effect was not obvious over 30 W. Therefore, the low ultrasonic power can be just set in the drying process. The values of the apparent activation energy in the first falling rate period were down from 13.52 to 12.78 kJ mol−1, and from 17.21 to 15.10 kJ mol−1 for the second falling rate period with increasing the ultrasonic power from 30 to 150 W. The values of the apparent activation energy in two falling rate periods with the ultrasound-assist were less than that for the hot air convective drying alone.

In the 21st century, people migrated from rural to urban areas for several reasons. As a result, the populations of Indian cities are increasing day by day. On one hand, the country is developing in the field of science and technology and on the other hand, it is encountering a serious problem called 'Environmental degradation'. Due to increase in population, the generation of solid waste is also increased and is being disposed in open dumps and landfills which lead to air and land pollution. This study is attempted to generate energy out of organic solid waste by the bio- fermentation process. The study was conducted for a period of 7 months at Erode, Tamilnadu and the reading on various parameters like Hydraulic retention time, organic loading rate, sludge loading rate, influent pH, effluent pH, inlet volatile acids, out let volatile fatty acids, inlet VSS/TS ratio, outlet VSS/TS ratio, influent COD, effluent COD and % of COD removal are recorded for every 10 days. The aim of the present study is to develop a model through multiple linear regression analysis with COD as dependent variable and various parameters like HRT, OLR, SLR, influent, effluent, VSS/TS ratio, influent COD, effluent COD, etc as independent variables and to analyze the impact of these parameters on COD. The results of the model developed through step-wise regression method revealed that only four parameters Influent COD, effluent COD, VSS/TS and Influent/pH were main influencers of COD removal. The parameters influent COD and VSS/TS have positive impact on COD removal and the parameters effluent COD and Influent/pH have negative impact. The parameter Influent COD has the highest order of impact, followed by effluent COD, VSS/TS and influent pH. The other parameters HRT, OLR, SLR, INLET VFA and OUTLET VFA were not significantly contributing to the removal of COD. The implementation of the process suggested through this study might bring in dual benefit to the community, viz treatment of solid waste and creation of energy.

Understanding how wastewater treatment plants (WWTPs) process microplastics (MPs) will help informing management practices to reduce MP emissions to the environment. We show that composite 24 h samples taken at three replications from the outflow of the grit chamber, primary settling tank and clarifier of the WWTP of Sari City, on the southern coast of the Caspian Sea, contained 12667 ± 668, 3514 ± 543 and 423 ± 44.9 MP/m3, respectively. Fibers accounted for 94.9%, 89.9% and 77.5% of the total number of MPs, respectively. The MP removal efficiency was 96.7%. MP shape (fiber, particle), size and structure were the most important factors determining their removal in different steps of the wastewater treatment process. The structure of microfibers (polyester, acrylic and nylon) and the consequent higher density than water explained their high removal (72.3%) in the primary settling tank. However, size was more important in microparticle removal with particles ≥500 μm being removed in the primary settling tank and

Moisture distributions in municipal sewage sludge, printing and dyeing sludge and paper mill sludge were experimentally studied based on four different methods, i.e., drying test, thermogravimetric-differential thermal analysis (TG-DTA) test, thermogravimetric-differential scanning calorimetry (TG-DSC) test and water activity test. The results indicated that the moistures in the mechanically dewatered sludges were interstitial water, surface water and bound water. The interstitial water accounted for more than 50% wet basis (wb) of the total moisture content. The bond strength of sludge moisture increased with decreasing moisture content, especially when the moisture content was lower than 50% wb. Furthermore, the comparison among the four different testing methods was presented. The drying test was advantaged by its ability to quantify free water, interstitial water, surface water and bound water; while TG-DSC test, TG-DTA test and water activity test were capable of determining the bond strength of moisture in sludge. It was found that the results from TG-DSC and TG-DTA test are more persuasive than water activity test.

A review of results of the research involving the quantitative and composition analyses of household waste conducted in Poland in recent years is presented in this paper. For these analyses various methodologies have been employed, as there is not one obligatory methodology how to characterise municipal solid waste. The results of the research in large Polish cities indicate great variability, which is difficult to be reasonably explained. This situation is affected by a number of factors, such as various methods and places for sample collection, various methods for tests, fractional character of most of the studies (studies carried out only in some periods during a year). Consequently, it is neither possible to measurably compare their results, nor to generalise them. Hence, within this article only individual data for large cities is provided. It is therefore necessary to standardise methodology for such analyses in Europe, taking into account local variability (such as different housing patterns, climate and waste collection schemes) to allow comparison of results. Reported yearly household waste generation in Polish cities varies from 238 to 309 kg per inhabitant. Biodegradable waste is a strongly dominated fraction in household waste from Polish cities, followed by paper/cardboard and plastics. Historical data shows that waste composition has undergone profound changes, the most significant being an increase of the share of plastics and decrease of fine fraction. The presented data indicates that waste composition strongly depends on the type of housing and its heating system. In the new multi-family buildings with central heating the share of paper and plastics is higher than in old houses with individual heating. In the latter ones the share of fine fraction is higher.

The present position paper addresses contemporary waste management options, weaknesses and opportunities faced by Hellenic local authorities. It focuses on state-of-the-art, tested as well as innovative, environmental management tools on a municipal scale and identifies a range of different collaboration schemes between local authorities and related service providers. Currently, a policy implementation gap is still experienced among Hellenic local authorities; it appears that administration at the local level is inadequate to manage and implement many of the general policies proposed; identify, collect, monitor and assess relevant data; and safeguard efficient and effective implementation of MSWM practices in the framework of integrated environmental management as well. This shortfall is partly due to the decentralisation of waste management issues to local authorities without a parallel substantial budgetary and capacity support, thus resulting in local activity remaining often disoriented and isolated from national strategies, therefore yielding significant planning and implementation problems and delays against pressing issues at hand as well as loss or poor use of available funds. This paper develops a systemic approach for MSWM at both the household and the non-household level, summarizes state-of-the-art available tools and compiles a set of guidelines for developing waste management master plans at the municipal level. It aims to provide a framework in the MSWM field for municipalities in Greece as well as other countries facing similar problems under often comparable socioeconomic settings.

Bio-hydrogen production from dry thermophilic anaerobic co-digestion (55°C and 20% total solids) of organic fraction of municipal solid waste (OFMSW) and food waste (FW) was studied. OFMSW coming from mechanical-biological treatment plants (MBT plants) presents a low organic matter concentration. However, FW has a high organic matter content but several problems by accumulation of volatile fatty acids (VFAs) and system acidification. Tests were conducted using a mixture ratio of 80:20 (OFSMW:FW), to avoid the aforementioned problems. Different solid retention times (SRTs) - 6.6, 4.4, 2.4 and 1.9 days - were tested. It was noted that addition of food waste enhances the hydrogen production in all the SRTs tested. Best results were obtained at 1.9-day SRT. It was observed an increase from 0.64 to 2.51 L H2/L(reactor) day in hydrogen productivity when SRTs decrease from 6.6 to 1.9 days. However, the hydrogen yield increases slightly from 33.7 to 38 mL H2/gVS(added).

PCN bacteria capable of heterotrophic-aerobic nitrogen removal was successfully applied for bioaugmented treatment of municipal wastewater in a pilot-scale SBR. At an appropriate COD/N ratio of 8, the bioaugmentation system exhibited stable and excellent carbon and nutrients removal, the averaged effluent concentrations of COD, NH4(+)-N, TN and TP were 20.6, 0.69, 14.1 and 0.40 mg/L, respectively, which could meet the first class requirement of the National Municipal Wastewater Discharge Standards of China (COD

This work deals with the analysis of the methane production from Mexico City’s urban organic wastes after separating soluble from suspended substances. Water was used to extract soluble substances under three different water to waste ratios and after three extraction procedures. Methane production was measured at 35 °C during 21 days using a commercial methane potential testing device. Results indicate that volatile solids extraction increases with dilution rate to a maximum of 40% at 20 °C and to 43% at 93 °C. The extracts methane production increases with the dilution rate as a result of enhanced dissolved solids extraction. The combined (extract and bagasse) methane production reached, in 6 days, 66% of the total methane produced in 21 days. The highest methane production rates were measured during the first six days.

This paper examines the effect of mixing on the performance of thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste during the start-up phase and in the absence of an acclimated seed. For this purpose, two digesters were used under similar starting conditions and operated for 235 days with different mixing schemes. While both digesters exhibited a successful startup with comparable specific methane yield of 0.327 and 0.314 l CH4/g VS, continuous slow stirring improved stability by reducing average VFA accumulation from 2890 to 825 mg HAc/l, propionate content from 2073 to 488 mg/l, and VFA-to-alkalinity ratio from 0.32 to 0.07. As a result, the startup with slow mixing was faster and smoother accomplishing a higher loading capacity of 2.5 g VS/l/d in comparison to 1.9 g VS/l/d for non-mixing. Mixing equally improved microbial abundance from 6.6 to 10 g VSS/l and enhanced solids and soluble COD removal.

Recycling of materials from municipal solid waste is commonly considered to be superior to any other waste treatment alternative. For the material fractions with a significant energy content this might not be the case if the treatment alternative is a waste-to-energy plant with high energy recovery rates. The environmental impacts from recycling and from incineration of six material fractions in household waste have been compared through life cycle assessment assuming high-performance technologies for material recycling as well as for waste incineration. The results showed that there are environmental benefits when recycling paper, glass, steel and aluminium instead of incinerating it. For cardboard and plastic the results were more unclear, depending on the level of energy recovery at the incineration plant, the system boundaries chosen and which impact category was in focus. Further, the environmental impact potentials from collection, pre-treatment and transport was compared to the environmental benefit from recycling and this showed that with the right means of transport, recyclables can in most cases be transported long distances. However, the results also showed that recycling of some of the material fractions can only contribute marginally in improving the overall waste management system taking into consideration their limited content in average Danish household waste.

This paper focused on the factors affecting the respiration rate of the digestate taken from a continuous anaerobic two-stage process treating the organic fraction of municipal solid waste (OFMSW). The process involved a hydrolytic reactor (HR) that produced a leachate fed to a submerged anaerobic membrane bioreactor (SAMBR). It was found that a volatile solids (VS) removal in the range 40-75% and an operating temperature in the HR between 21 and 35 °C resulted in digestates with similar respiration rates, with all digestates requiring 17 days of aeration before satisfying the British Standard Institution stability threshold of 16 mg CO(2) g VS(-1) day(-1). Sanitization of the digestate at 65 °C for 7 days allowed a mature digestate to be obtained. At 4 g VS L(-1) d(-1) and Solid Retention Times (SRT) greater than 70 days, all the digestates emitted CO(2) at a rate lower than 25 mg CO(2) g VS(-1) d(-1) after 3 days of aeration, while at SRT lower than 20 days all the digestates displayed a respiration rate greater than 25 mg CO(2) g VS(-1) d(-1). The compliance criteria for Class I digestate set by the European Commission (EC) and British Standard Institution (BSI) could not be met because of nickel and chromium contamination, which was probably due to attrition of the stainless steel stirrer in the HR.

Inorganic urban solid waste (IUSW) is a serious problem in developing countries, and IUSW in the street that does not have adequate final disposal is responsible for serious environmental effects. The aim of this work was to determine the dynamics of the generation of IUSW in the streets of two neighborhoods of different socioeconomic strata in Mexico City during 5 weeks in 2006. The amount of IUSW was recorded every day from 9:00 to 12:00 h, separated, classified, and registered. It was found that plastic (50%) and paper (44.5%) wastes were found most frequently, whereas, textiles (0.4%) and glass (0.5%) wastes were present less frequently in all samples. The IUSWs without commercial brands were more abundant. Branded plastic wrappers of PepsiCo and Bimbo, as well as polyethylene terephthalate (PET) containers of Coca Cola, registered the highest values, while Gatorade, Barrilitos, and Peñafiel registered the lowest. The neighborhood with a higher income and more vegetation on sidewalks or in jardinières, which are used to hide solid waste, had more IUSW than the neighborhood with lower income, where IUSW was thrown out directly into the street. The knowledge of the real generation and composition of IUSW will contribute to the prevention of its negative environmental and social impacts, as well as guarantee the efficiency of its sustainable management.

Effect of mine wastewater on the nutrient removal efficiency of a green microalga Micratinium reisseri from concentrated municipal wastewater (CMW) with simultaneous lipid production was investigated. Different dilution ratios (1–10%) of CMW either with mine wastewater (MWF) or mine wastewater without Fe (MWOF) were used. M. reisseri showed the highest growth (0.8 g L−1) and nutrient uptake (35.9 mg TN L−1 and 5.4 mg TP L−1) at 3% MWF ([Fe]tot = 6.7 mg L−1), and the highest lipid productivity (10.4 mg L−1 day−1) at 5% MWF ([Fe]tot = 11.2 mg L−1) after 15 days. CMW supported the algal autoflocculation due to formation of phosphate, calcium and magnesium precipitates at a high suspension pH. Fatty acid methyl ester analysis revealed that the microalgal lipids possessed 79–82% of C16/C18 fatty acids. Application of mine wastewater improved the nutrient removal efficiency, growth and lipid productivity of M. reisseri cultivated in CMW.

Nutrient removal from primary wastewater effluent was tested using Galdieria sulphuraria, an acidophilic and moderately thermophilic alga. Biomass yield recorded in this study (27.42 g biomass per g nitrogen removed) is higher than the average reported in the literature (25.75 g g−1) while, the theoretical yield estimated from the empirical molecular formula of algal biomass is 15.8 g g−1. Seven-day removal efficiencies were 88.3% for ammoniacal-nitrogen and 95.5% for phosphates; corresponding removal rates were 4.85 and 1.21 mg L−1 d−1. Although these rates are lower than the average literature values for other strains (6.36 and 1.34 mg L−1 d−1, respectively), potential advantages of G. sulphuraria for accomplishing energy-positive nutrient removal are highlighted. Feasibility of growing G. sulphuraria outdoors at densities higher than in high-rate oxidation ponds is also demonstrated.

The use of biological pretreatment in anaerobic digestion systems has some potential; however, to date, these methods have not been able to effectively increase methane production of lignocellulose of municipal solid waste (LMSW). In this study a thermophilic microbial consortium (MC1) was used as a pretreatment method in order to enhance biogas and methane production yields. The results indicated that sCOD concentration increased significantly in the early stages of pretreatment. Ethanol, acetic acid, propionic acid, and butyric acid were the predominant volatile organic products in the MC1 hydrolysate. Biogas and methane production yields of LMSW significantly increased following MC1 pretreatment. In addition, the methane production rate of the treated LMSW was greater than that observed from the untreated sample.

The microbial community composition of a down-flow hanging sponge (DHS) reactor in an up-flow anaerobic sludge blanket (UASB)-DHS system used for the treatment of municipal sewage was investigated. The clone libraries showed marked differences in microbial community composition at different reactor heights and in different seasons. The dominant phylotypes residing in the upper part of the reactor were likely responsible for removing organic matters because a significant reduction in organic matter in the upper part was observed. Quantification of the amoA genes revealed that the proportions of ammonia oxidizing bacteria (AOB) varied along the vertical length of the reactor, with more AOB colonizing the middle and lower parts of the reactor than the top of the reactor. The findings indicated that sewage treatment was achieved by a separation of microbial habitats responsible for organic matter removal and nitrification in the DHS reactor.

The prevalence of antimicrobial resistant (AMR) bacteria is increasing worldwide and remains a significant medical challenge which may lead to antimicrobial redundancy. The contribution of hospital effluent to the prevalence of resistance in wastewater treatment plant (WWTP) effluents is not fully understood. AMR bacteria contained in hospital effluent may be released into the aquatic and soil environments after WWTP processing. Hence, the objective of this study is to identify the extent hospital effluent contributes to contamination of these environments by comparing two WWTPs, one which receives hospital effluent and one which does not. AMR Escherichia coli were monitored in the two WWTPs. A model was developed using these monitored values to predict the effect of hospital effluent within a WWTP. The model predicted levels of AMR E. coli in the aquatic environment and potential bather exposure to AMR E. coli. The model results were highly variable. WWTP influent containing hospital effluent had a higher mean percentage of AMR E. coli; although, there appeared to be no within treatment plant effect on the prevalence of AMR E. coli. Examination of WWTP sludge showed a similar variation. There appeared to be no consistent effect from the presence of hospital effluent. The human exposure assessment model predicted swimmer intake of AMR E. coli between 6 and 193CFU/100ml sea water. It appears that hospital effluent is not the main contributing factor behind the development and persistence of AMR E. coli within WWTPs, although resistance may be too well-developed to identify an influence from hospital effluent. Mitigation needs to focus on the removal of already present resistant bacteria but for new or hospital specific antimicrobials focus needs to be on their limited release within effluents or separate treatment.

In the conventional activated sludge process, a number of important parameters determining the efficiency of settling and dewatering are often linked to specific groups of bacteria in the sludge--namely floc size, residual turbidity, shear sensitivity and composition of extracellular polymeric substances (EPS). In membrane bioreactors (MBRs) the nature of solids separation at the membrane has much in common with sludge dewaterability but less is known about the effect of specific microbial groups on the sludge characteristics that affect this process. In this study, six full-scale MBR plants were investigated to identify correlations between sludge filterability, sludge characteristics, and microbial community structure. The microbial community structure was described by quantitative fluorescence in situ hybridization and sludge filterability by a low-pressure filtration method. A strong correlation between the degree of flocculation (ratio between floc size and residual turbidity) and sludge filterability at low pressure was found. A good balance between EPS and cations in the sludge correlated with good flocculation, relatively large sludge flocs, and low amounts of small particles and single cells in the bulk phase (measured as residual turbidity), all leading to a good filterability. Floc properties could also be linked to the microbial community structure. Bacterial species forming strong microcolonies such as Nitrospira and Accumulibacter were present in plants with good flocculation and filtration properties, while few strong microcolonies and many filamentous bacteria in the plants correlated with poor flocculation and filtration problems. In conclusion this study extends the hitherto accepted perception that plant operation affects floc properties which affects fouling. Additionally, plant operation also affects species composition, which affects floc properties and in the end fouling propensity.

This work describes the generation of volatile fatty acids (VFAs) as the first step of the polyhydroxyalkanoate (PHA) production cycle. Therefore four different substrates from a municipal waste water treatment plant (WWTP) were investigated regarding high VFA production and stable VFA composition. Due to its highest VFA yield primary sludge was used as substrate to test a series of operating conditions (temperature, pH, retention time (RT) and withdrawal (WD)) in order to find suitable conditions for a stable VFA production. The results demonstrated that although the substrate primary sludge differs in its consistence a stable composition of VFA could be achieved. Experiments with a semi-continuous reactor operation showed that a short RT of 4 d and a small WD of 25% at pH = 6 and around 30 °C is preferable for high VFA mass flow (MF = 1913 mg VFA /(L d)) and a stable VFA composition.

The removal of seven pharmaceuticals and two fragrances in the biological units of various full-scale municipal wastewater treatment plants was studied. The observed removal of pharmaceuticals was mainly due to biological transformation and varied from insignificant (10%, carbamazepine) to90% (ibuprofen). However, no quantitative relationship between structure and activity can be set up for the biological transformation. Overall, it can be concluded that for compounds showing a sorption coefficient (K(d)) of below 300 L kg(-1), sorption onto secondary sludge is not relevant and their transformation can consequently be assessed simply by comparing influent and effluent concentrations. The two fragrances (HHCB, AHTN) studied were mainly removed by sorption onto sludge. For the compounds studied, comparable transformation and sorption was seen for different reactor types (conventional activated sludge, membrane bioreactor and fixed bed reactor) as well as for sludge ages between 10 and 60-80 days and temperatures between 12 degrees C and 21 degrees C. However, some significant variations in the observed removal currently lack an explanation. The observed incoming daily load of iopromide and roxithromycin in medium-sized municipal wastewater treatment plants (up to 80,000 population equivalents) is generated by only a small number of patients: the consequences for representative 24h composite sampling are discussed. Generally, the paper presents a method for setting up mass balances for micropollutants over entire wastewater treatment plants, including an estimation of the accuracy of the quantified fate (i.e. removal by sorption and biological transformation).

The effect on process performance of adding increasing proportions of biodiesel waste glycerin (BWG) to municipal wastewater sludge (MWS) was studied using two 1300 L pilot-scale digesters under mesophilic conditions at 20 days SRT. The highest proportion of BWG that did not cause a process upset was determined to be 23% and 35% of the total 1.04 kg VS/(m(3)d) and 2.38 kg COD/(m(3)d) loadings, respectively. At this loading, the biogas and methane production rates in the test digester were 1.65 and 1.83 times greater than of those in the control digester which received only MWS, respectively. The COD and VS removal rates at this loading in the test digester were 1.82 and 1.63-fold those of the control digester, respectively. Process instability was observed when the proportion of BWG in the test digester feed was 31% and 46% of the 1.18 kg VS/(m(3)d) and 2.88 kg COD/(m(3)d) loadings, respectively.

This work showed that sewage sludge could be a strong candidate for biodiesel production. High lipid content (18–20%) with C 16−18 -carbon range was experimentally identified and measured. These lipids from sewage sludge were converted into biodiesel via the transesterification reaction with MgO–CaO/Al 2 O 3 derived from magnesium slag, and biodiesel conversion was ∼98%. The experimental work enabled explaining that temperature is the main driving force for the transesterification reaction, which can be enhanced in the presence of CO 2 . This also enables combination of esterification of free fatty acids and transesterification of triglycerides into a single process within 1 min in the temperature range of 350–500 °C. Sewage sludge residue after extracting lipids was also a good feedstock for recovering energy via thermo-chemical processes. The impact of CO 2 co-feed on the pyrolysis/gasification process of SS residue was also investigated in this work. The CO 2 injected into the thermo-chemical process remarkably increased the generation of CO by a factor of 2. Moreover, the introduction of CO 2 into the pyrolysis/gasification process enabled reducing condensable hydrocarbons (tar) by expediting cracking; thus, utilizing CO 2 as chemical feedstock for the gasification process not only leads to higher thermal efficiency but also has environmental benefits.

Different types of carriers were tested as support material in a lab-scale moving bed biofilm reactor (MBBR) used to treat urban wastewater under three different conditions of hydraulic retention time (HRT) and carrier filling ratios (FR). The bacterial diversity developed on the biofilms responsible of the treatment was studied using a cultivation-independent approach based on the polymerase chain reaction-temperature gradient gel electrophoresis technique (PCR-TGGE). Cluster analysis of TGGE fingerprints showed significant differences of community structure dependent upon the different operational conditions applied. Redundancy analysis (RDA) was used to determine the relationship between the operational conditions (type of carrier, HRT, FR) and bacterial biofilm diversity, demonstrating a significant effect of FR=50%. Phylogenetic analysis of PCR-reamplified and sequenced TGGE bands revealed that the prevalent Bacteria populations in the biofilm were related to Betaproteobacteria (46%), Firmicutes (34%),Alphaproteobacteria (14%) and Gammaproteobacteria (9%).

This study was carried out to assess the impact of organic loading rate (OLR) on the performance of mesophilic anaerobic baffled reactor (ABR) for H(2) production from a co-digestion of municipal food waste and kitchen wastewater. The reactor was operated at different organic loading rates (OLRs) of 29, 36 and 47 g COD(total)/Ld. The hydraulic retention time (HRT) was kept constant at 1.6d. The results showed that increasing the OLR from 29 to 36 g COD(total)/Ld, leads to a significant (p □ 0.01) drop in the H(2) production from 6.0±0.5 to 5.4±1.04 L H(2)/d, respectively. However, the H(2) production remained at the same level of 5.3±1.04 L H(2)/d at increasing the OLR from 36 to 47 g COD(total)/Ld. The H(2) generation was mainly due to conversion of COD (57%) and carbohydrate (81%). Protein and lipids conversion represents only 23.3% and 4.1% respectively for H(2) production.

Silver nanoparticles (AgNPs, nanosilver) released from industrial activities and consumer products may be disposed directly or indirectly in sanitary landfills. To determine the impact of AgNPs on anaerobic digestion of landfill waste, municipal solid waste (MSW) was loaded in identical landfill bioreactors (9 L volume each) and exposed to AgNPs (average particle size = 21 nm) at the final concentrations of 0, 1, and 10 mg Ag/kg solids. The landfill anaerobic digestion was carried out for more than 250 days, during which time the cumulative biogas production was recorded automatically and the chemical property changes of leachates were analyzed. There were no significant differences in the cumulative biogas volume or gas production rate between the groups of control and 1 mg Ag/kg. However, landfill solids exposed to AgNPs at 10 mg/kg resulted in the reduced biogas production, the accumulation of volatile fatty acids (including acetic acid), and the prolonged period of low leachate pH (between 5 and 6). Quantitative PCR results after day 100 indicated that the total copy numbers of 16S rRNA gene of methanogens in the groups of control and 1 mg AgNPs/kg were 1.97 ± 0.21 × 10 7 and 0.90 ± 0.03 × 10 7 , respectively. These numbers were significantly reduced to 5.79 ± 2.83 × 10 5 (copies/mL) in the bioreactor treated with 10 mg AgNPs/kg. The results suggest that AgNPs at the concentration of 1 mg/kg solids have minimal impact on landfill anaerobic digestion, but a concentration at 10 mg/kg or higher inhibit methanogenesis and biogas production from MSW.

This study aimed to evaluate the performances of sequencing batch biofilm reactors (SBBRs) in removing nitrogen and phosphorus from synthetic municipal wastewater with different carbon to total nitrogen (C/ N) ratios. The effect of control systems, including an intelligent control system (ICS) and conventional timer control system (TCS) on the performance of SBBRs was also investigated. When C/N ratios were 10.0, 5.0 and 3.3, the average COD removal efficiencies in the ICS-SBBR reached 87.7%, 92.3% and 97.6%, while total phosphorous (TP) removals reached 95.0%, 97.0% and 97.2%. When the C/N ratio was 5.0, the TN removal efficiency was 81.0% under ICS and 65.4% under TCS. Moreover, compared with TCS-SBBR, both reaction time and aeration time were shortened by 180 min and 157 min, respectively, in the ICS-SBBR. Therefore, the ICS-SBBR has potential in practical applications for significant nitrogen and phosphorus removal and energy savings.

A pilot scale anaerobic submerged membrane bioreactor (AnSMBR) with an external filtration unit for municipal wastewater treatment was operated for 100 days. Besides gas sparging, additional shear was created by circulating sludge to control membrane fouling. During the first 69 days, the reactor was operated under mesophilic temperature conditions. Afterwards, the temperature was gradually reduced to 20 °C. A slow and linear increase in the filtration resistance was observed under critical flux conditions (7 L/(m 2 h)) at 35 °C. However, an increase in the fouling rate probably linked to an accumulation of solids, a higher viscosity and soluble COD concentrations in the reactor was observed at 20 °C. The COD removal efficiency was close to 90% under both temperature ranges. Effluent COD and BOD 5 concentrations were lower than 80 and 25 mg/L, respectively. Pathogen indicator microorganisms (fecal coliforms bacteria) were reduced by log 10 5. Hence, the effluent could be used for irrigation purposes in agriculture.

An anoxic/oxic step feeding process was improved to enhance nutrient removal by reconfiguring the process into (1) anaerobic/anoxic/oxic step feeding process or (2) modified University of Capetown (UCT) step feeding process. Enhanced nitrogen and phosphorus removal and optimized organics utilization were obtained simultaneously in the modified UCT type with both internal and sludge recycle ratios of 75% as well as anaerobic/anoxic/oxic volume ratio of 1:3:6. Specifically, the UCT configuration and optimized operational conditions lead to the enrichment of denitrifying phosphorus removal microorganisms and achieved improved anaerobic P-release and anoxic P-uptake activities, which were beneficial to the denitrifying phosphorus removal activities and removal efficiencies. Due to high mixed liquor suspended solid and uneven distributed dissolved oxygen, 35% of total nitrogen was eliminated through simultaneous nitrification and denitrification process in aerobic zones. Moreover, 62 ± 6% of influent chemical oxygen demands was involved in the denitrification or phosphorus release processes.

A wastewater-born and settleable algal-bacterial culture, cultivated in a stirred tank photobioreactor under lab conditions, was used to remove the carbon and nutrients in municipal wastewater and accumulate biomass simultaneously. The algal-bacterial culture showed good settleable property and could totally settle down over 20 min, resulting in a reduction of total suspended solids from an initial 1.84 to 0.016 g/l. The average removal efficiencies of chemical oxygen demand, total kjeldahl nitrogen and phosphate were 98.2 ± 1.3%, 88.3 ± 1.6% and 64.8 ± 1.0% within 8 days, respectively, while the average biomass productivity was 10.9 ± 1.1 g/m(2) · d. Accumulation into biomass, identified as the main nitrogen and phosphorus removal mechanism, accounted for 44.9 ± 0.4% and 61.6 ± 0.5% of total inlet nitrogen and phosphorus, respectively. Microscopic analysis showed the main algae species in the bioreactor were filamentous blue-green algae. Furthermore, denaturing gradient gel electrophoresis and 16S rDNA gene sequencing revealed that the main bacteria present in the photobioreactor were consortia with sequences similar to those of Flavobacteria, Gammaproteobacteria, Bacteroidia and Betaproteobacteria. This study explores a better understanding of an algae-bacteria system and offers new information on further usage of biomass accumulated during treatment.

Solid retention time (SRT) is a very important operational variable in continuous and semicontinuous waste treatment processes since the organic matter removal efficiency – expressed in terms of percentage of Dissolved Organic Carbon (% DOC) or Volatile Solids (% VS) removed – and the biogas or methane production are closely related with the SRT imposed. Optimum SRT is depending on the waste characteristics and the microorganisms involved in the process and, hence, it should be determined specifically in each case. In this work a series of experiments were carried out to determine the effect of SRT, from 40 to 8 days, on the performance of the dry (30% Total Solids) thermophilic (55 °C) anaerobic digestion of organic fraction of Municipal Solid Wastes (OFMSW) operating at semicontinuous regime of feeding. The experimental results show than 15 days is the optimum SRT (the best between all proved) for this process. Besides, data of organic matter concentration and methane production versus SRT have been used to obtain the kinetic parameters of the kinetic model of Romero Garcia (1991) : the maximum specific growth rate of the microorganisms ( μ max = 0.580 days −1 ) and the fraction of substrate non-biodegradable ( α = 0.268).

The aim of this work was to study the effect of pH on electricity production and contaminant dynamics using microbial fuel cells (MFCs). To investigate these effects, an air-cathode MFC was used to treat urban wastewater by adjusting the pH between 6 and 10. The short-term tests showed that the highest power production (0.66 W.m(-3)) was at pH 9.5. The MFC operation in continuous control mode for 30 days and at the optimal pH improved the performance of the cell relative to power generation to 1.8 W.m(-3). Organic matter removal (77% of influent COD) and physical ammonium loss were directly influenced by pH and followed the same behavior as the power generation. At a pH higher than the optimal one, anodic bacteria were affected, and power generation ceased. However, biological nitrogen processes and phosphorus dynamics were independent of the exoelectrogenic bacteria.

In this present study, thermal hydrolysis pre-treatment improved the hydrolysis of organic solids and the solid-liquid separation ability of MB, making it possible to obtain a long solid retention time (SRT) and high degradation ratio in anaerobic sequencing batch reactor (ASBR). Biofilm carriers were introduced into ASBR to prolong the mean cell retention time (MCRT). The biofilm system operated at an organic loading rate (OLR) of 3.5-5 gVSL(reactor)(-1)day(-1) and a hydraulic retention time (HRT) of 13.3 days. The biofilm carriers provided perfect conditions for microbe retention and growth, improving the digestion efficiency. The MCRT was 89-150 days and SRT was 24-36 days, with the methane yield of 330-370 mL g(-1)VS(added) and VS(d) of 62-70%. Meanwhile, due to the mass-transport resistance and high microbe density of the biofilm, the system show high stability. Therefore, the biofilm system provided an approach for a highly efficient anaerobic digestion of municipal biowaste.

Sludge-fly ash ceramic particles (SFCP) and clay ceramic particles (CCP) were employed in two lab-scale up-flow biological aerated filters (BAF) for wastewater treatment to investigate the availability of SFCP used as biofilm support compared with CCP. For synthetic wastewater, under the selected hydraulic retention times (HRT) of 1.5, 0.75 and 0.37 h, respectively, the removal efficiencies of chemical oxygen demand (COD(Cr)) and ammonium nitrogen (NH(4)(+)-N) in SFCP reactor were all higher than those of CCP reactor all through the media height. Moreover, better capabilities responding to loading shock and faster recovery after short intermittence were observed in the SFCP reactor compared with the CCP reactor. For municipal wastewater treatment, which was carried out under HRT of 0.75 h, air-liquid ratio of 7.5 and backwashing period of 48 h, the SFCP reactor also performed better than the CCP reactor, especially for the removal of NH(4)(+)-N.

Fewer and fewer municipal solid wastes are treated by composting in China because of the disadvantages of enormous investment, long processing cycle and unstable products in a conventional composting treatment. In this study, a continuous thermophilic composting (CTC) method, only a thermophilic phase within the process, has been applied to four bench-scale composting runs, and further compared with a conventional composting run by assessing the indexes of pH, total organic carbon (TOC), total Kjeldahl nitrogen (TKN), C/N ratio, germination index (GI), specific oxygen uptake rate (SOUR), dissolved organic carbon (DOC) and dehydrogenase activity. After composting for 14 days, 16 days, 18 days and 19 days in the four CTC runs, respectively, mature compost products were obtained, with quality similar to or better than which had been stabilized for 28 days in run A. The products from the CTC runs also showed favorable stability in room temperature environment after the short-term composting at high temperature. The study suggested CTC as a novel method for rapid degradation and maturation of organic municipal solid wastes.