bluuebunny/crossref_metadata_2025 huggingface dataset:
Constructed wetland technology transfer to Nepal
Authors: Shrestha R. R. , Haberl R. , Laber J.
Published: May 2018

Constructed Wetland (CW) technology is still not wide spread in developing countries despite having great potential. This paper describes an approach carried out in Nepal to transfer CW technology for wastewater treatment. Three CWs (hospital wastewater treatment - 20 m3/d, greywater treatment of a single household, septage treatment - 40 m3/d) were built and two have been investigated so far. All systems are subsurface flow systems with at least one vertical flow stage. Their treatment efficiency turned out to be very high. Median load elimination rates of the hospital wastewater and greywater treatment plants were for TSS: 97 to 99%; BOD5: 97 to 99%; COD: 94 to 97%; NH4-0N 80 to 99%; PO4-P: 5 to 69%; Total Coliforms: 99.87 to 99.999% (3 - 5 log steps). Beside the treatment task the plants play an important role as demonstration sites to make common people and especially decision makers aware of the existing environmental problems and one possible solution. Several recommendations are pointed out to promote the technology in developing countries.
A new analytical tool to assess health risks associated with the virological quality of drinking water (EMIRA study)
Authors: Gofti-Laroche L. , Gratacap-Cavallier B. , Genoulaz O. , Joret J. C. , Hartemann Ph. , Seigneurin J. M. , Zmirou D.
Published: May 2018

This work assessed the risks associated with the virological quality of tapwater using a molecular analytical tool manageable in a field survey. It combined a daily epidemiological follow-up of digestive morbidity among a panel of volunteers and a microbiological surveillance of drinking water. RT-PCR was used for detection of enterovirus, rotavirus and astrovirus. 712 cases of acute digestive conditions occurred in the 544 volunteers. 38% (9/24) raw water and 23% (10/44) tap water samples were positive for at least one virus marker with 9/10 positive tap water samples complying with bacterial criteria. No statistically significant association was found between the presence of viral markers and observed incidence of digestive morbidity. However, when an outbreak occurred, enterovirus and rotavirus RNA was detected in the corresponding stored tap water samples. Sequencing of the amplified fragments showed that the rotavirus detected was of bovine origin. This work demonstrated that enteric virus markers were common in tapwater of the study communities (characterised by a vulnerable raw water) despite absence of bacterial indicators. Tangential ultrafiltration coupled to RT-PCR allowed a simultaneous and fast detection of the study viruses from environmental samples. This process is a promising tool usable for virological water surveillance, in as much the corresponding know-how is transferred to the field professionals.
Characterisation of the impact of aqueous industrial waste in mesocosms: biological indicators and pilot streams
Authors: Bassères A. , Tramier B.
Published: May 2018

The use of exposure biomarkers in measuring the impact of aqueous waste holds out promise because such tools have short response times, are of flexible use and give an indication of the type of pollution. However, their ecological significance has not yet been demonstrated. During field studies focusing on aqueous industrial waste, the correlations obtained between several biocoenotic indicators and biomarkers measured in a fresh-water bivalve (Corbicula fluminea), demonstrate the need for work to be carried out under controlled conditions.

Working in partnership with the Adour Garonne Water Board, the ELF company has developed a pilot scheme incorporating such controlled conditions. This pilot is made up of 16 canals 40 m in length supplied by river water. The pilot scheme, which is currently at the validation stage, makes it possible to reconstitute an aquatic ecosystem which, once established, will be exposed to perfectly controlled pollution conditions. The responses provided by all the indicators - biocoenotic and microbiological indicators, biomarkers - will then be correlated in order to attribute an ecological significance to the biomarkers.
Monitoring and troubleshooting of non-filamentous settling and dewatering problems in an industrial activated sludge treatment plant
Authors: Kjellerup B. V. , Keiding K. , Nielsen P. H.
Published: May 2018

A large industrial activated sludge wastewater treatment plant had temporary problems with settling and dewatering of the sludge. Microscopical investigations revealed that the poor settling properties were not due to presence of filamentous bacteria, but poor floc properties. In order to characterise the changes in floc properties that led to settling and dewatering problems and to find reasons for this taking place, a comprehensive monitoring program was conducted during more than one year. The monitoring program included various measurements of floc settleability, floc strength and sludge dewaterability. The monitoring program revealed that a deterioration of the floc strength and the settling properties in the process tanks was closely connected to downstream dewatering problems and poor effluent quality. Particularly severe problems were observed a few weeks after the production at the factory had started after summer closedown. Possible reasons for the changes in floc properties in the process tanks were found by a) analysing change in wastewater composition by evaluating the different production lines in the industrial plant, b) evaluating the operation of the plant, and c) performing short-term laboratory experiments testing factors that could potentially affect floc properties (absence of oxygen, presence of sulphide, detergents, etc). Among several measured parameters, the use of floc strength measurements in particular proved useful to monitor the activated sludge floc properties at this industrial plant. The described strategy can be useful in general to find and solve many solid/liquid separation problems in activated sludge wastewater treatment plants.
Biological nitrogen removal from industrial wastewater discharged from metal recovery processes
Authors: Hirata A. , Nakamura Y. , Tsuneda S.
Published: May 2018

The wastewater generated from the processes of recovering precious metals from industrial wastes contains high concentrations of acids and alkalis such as nitric acid and aqueous ammonia, and of salts such as sodium chloride and sodium sulfate. Biological nitrogen removal from this wastewater was attempted by using a circulating bioreactor system equipped with an anaerobic packed bed and an aerobic three-phase fluidized bed. As a result of acclimating microorganisms with change of the hydraulic residence time, this system effectively removed nitrogen from diluted wastewater (T-N: from 2,000 to 4,000 g/m3), such that the total nitrogen concentration in the effluent met the sewage discharge control criteria in Japan (240 g/m3). The removal ratio of total nitrogen was 90% to 98% and that of ammonia was 80% to 92%. In addition, the characteristic equations for biological treatment were applied to this system on the assumption that both reactions of denitrification in the anaerobic reactor and nitrification in the aerobic reactor can be approximated to a first-order reaction. This simplified approach successfully led to a new analytical method for simulating the optimum volume ratio of anaerobic reactor to aerobic reactor for minimizing the total hydraulic residence time.
Effects of solids concentration on activated sludge deflocculation, conditioning and dewatering
Authors: Mikkelsen L. H. , Keiding K.
Published: May 2018

Optimum conditioning of activated sludge in terms of minimum CST was shown to correspond to the complete removal of turbidity, and the increase in turbidity with shear due to e.g. pumping is therefore expected to affect conditioning. The optimum polymer dosage was directly related to the turbidity of activated sludge after two minutes shear, and was considerably lower than the dosage required for charge neutralisation. The turbidity produced by shear increased more than is proportional with solids concentration and was directly related to the apparent viscosity. It is suggested that increasing solids concentration causes increased surface erosion when network structures are broken, and this causes increases in turbidity and required polymer dosage per solids mass. For Åby activated sludge, optimum polymer dosage per solids mass increased by 52% when the solids concentration was increased from 8.2 to 13.7 g SS/l. Modelling of the effect of solids concentration predicts even higher increases in required polymer dosage for higher solids concentrations. This means that reduced thickening prior to pumping and conditioning may be desirable when the hydraulic capacity of the dewatering device is sufficient. Similar trends were observed for an anaerobically digested sludge. For this sludge, reduction of turbidity with FeCl3 reduced the polymer demand.
Isolation of copper-binding proteins from activated sludge culture
Authors: Fukushi K. , Kato S. , Antsuki T. , Omura T.
Published: May 2018

Six copper-binding microbial proteins were isolated from activated sludge cultures grown on media containing copper at various concentrations. Molecular weights among isolated proteins were ranged from 1.3k to 174k dalton. Isolated proteins were compared for their copper binding capabilities. Proteins isolated from cultures grown in the presence of copper in the growth media exhibited higher copper binding capabilities than those isolated from the culture grown in the absence of copper. The highest metal uptake of 61.23 (mol copper/mol protein) was observed by a protein isolated from a culture grown with copper at a concentration of 0.25 mM. This isolated protein (CBP2) had a molecular weight of 24k dalton. Other protein exhibited copper binding capability of 4.8-32.5 (mol copper/mol protein).
Nitrogen and phosphorus budget in rewetted fens
Authors: Lenz A. , Wild U.
Published: May 2018

A former dewatered fen was flooded for a multi-purpose landuse system including cattail production, fen protection, and water purification. These research plants with an area of 6 ha consist of three constructed surface-flow wetlands. The inflowing water is polluted by non-point sources due to intensive agriculture. The focus of this paper is the estimation of the potential of rewetted fens to reduce phosphorus and nitrogen. The dominating forms of nitrogen in the inflow are organic nitrogen and nitrate. The reduction rate is higher for nitrate than for organic nitrogen, although the nitrate reductions occur only during the summer season. If no nitrate is available for denitrification, there is a release of ammonia from the peat into the water. The main form of phosphorus in the in- and outflow is ortho-phosphate. In contrast to the values of nitrate, the concentrations of phosphorus are very regular with no significant seasonal pattern.

When nitrate isn't available in the water any more, the release of phosphorus begins and the rewetted fens change from a sink for phosphorus to a source of it. Rewetted fens can be a sink for phosphorus and nitrogen with nitrate as the limiting factor. Only if denitrification can occur, can the release of ammonia and phosphorus from the peat layer be prevented.
Denitrification in free water surface wetlands receiving carbon supplements
Authors: Burgoon P.S.
Published: May 2018

Wetlands may be used as fixed film reactors for removal of NO3-N in wastewater. Two 1 hectare free water surface wetlands were constructed for denitrification of nitrified effluent from intermittent sand filters in Connell, Washington. The wetlands were designed to remove NO3-N from wastewater prior to land application. The design flow as 5300 m3/d (1.4 mgd). Primary effluent from a potato processing facility was used as a carbon supplement for detnitrification. Addition of primary effluent (COD = 2800 mg/L) resulted in a COD:NO3-N mass load ratio that ranged from 10 to 25. The total hydraulic retention time in the two wetlands varied from 1-2 days in the summer and winter. The NO3-N load ranged from 10 to110 kg/ha d. The NO3-N mass removal rate ranged from 50 to 99% of the influent load. During the five months of data presented, January to May 1998, average monthly effluent NO3-N was 1.6 mg/L; monthly average influent NO3-N was 20.5 mg/L. An average of >85% of the NO3-N influent load was removed. The NO3-N removal rate coefficient (K20 = 358 m/yr) was higher than that measured in wetlands without carbon supplements and was independent of temperature above 12°C.
Behavior of organic carbon during subsurface wetland treatment in the Sonoran Desert
Authors: Quanrud D.M. , Karpiscak M.M. , Lansey K.E. , Arnold R.G.
Published: May 2018

We examined the fate of organics during wetland treatment of secondary effluent and groundwater (control) flows in parallel, research-scale, subsurface-flow (SSF) wetland raceways at the Constructed Ecosystem Research Facility (CERF) located in Tucson, Arizona. The CERF facility enabled us to distinguish experimentally among effects on effluent quality due to season-dependent processes of evapotranspiration (ET) and wetlands-derived production of organics. Organics of wastewater and wetlands origin were compared in terms of their contributions to dissolved organic carbon (DOC) in wetland effluent. Elevated temperatures and associated biochemical activities increased DOC levels in wetland effluents during summer. In other words, DOC removal efficiency was negatively correlated to temperature. The contributions of ET and wetland-derived organics to elevation of DOC in wetland effluents during summer were roughly comparable. The elevation of organic carbon concentration during wetland polishing of wastewater effluent will lead to higher levels of disinfection by-products when treated waters are chlorinated prior to reuse. Results of this work are relevant to water managers in arid regions, which may incorporate wetlands into sequential wastewater treatments leading to potable reuse of reclaimed water.
Rerating capacity of a constructed wetland treatment system
Authors: Jackson J.A. , Sees M.
Published: May 2018

The 482-hectare (ha) City of Orlando (Florida) Easterly Wetlands (OEW) was designed to reduce nutrient concentrations in 0.90 m3/s of wastewater from the Iron Bridge Regional Water Reclamation Facility. Design influent nutrient concentrations were 6 mg/L total nitrogen (TN) and 0.75 mg/L total phosphorus (TP).

Actual TN and TP concentrations have been less than design, averaging 2.6 mg/L and 0.29 mg/L, respectively from January 1988 through December 1999. If influent concentrations remain at these levels, the OEW may have the potential to treat significantly higher flows since less than 20% of the total area was utilized for nutrient reduction.

To test this theory, a capacity study was performed for approximately nine months in 1997 and 1998. Simulated flows of approximately 1.26 m3/s, 1.66 m3/s, and 1.93 m3/s were tested. It was found that approximately 15% of the area was utilized for nutrient reduction during the 1.26 m3/s simulation, 35% in the 1.66 m3/s, and 1.93 m3/s simulations. Based on these testing results, an application was submitted to the state in early 2000 to increase the permitted capacity to 1.57 m3/s.
Investigation of copper adsorption to peat using the simple metal sorption model
Authors: Dierks S.
Published: May 2018

The Simple Metal Sorption (SiMS) equilibrium model was used to simulate the proton/cation exchange behavior of peat with dissolved copper. The SiMS model represents proton binding and metal binding as cation exchange for heterogeneous sorbents as a function of pH, salt concentration, total metal concentration and total ligand concentration. The SiMS model uses fewer parameters than other cation exchange models for multidimensional datasets and can be executed on a standard spreadsheet. The cation exchange selectivity coefficient, KMe,app, is represented as KMe,app=KMe{H+}α(LT/MeT)βIphiv. The model is similar to standard surface complexation approaches, with an intrinsic relationship described by mass action laws (KMe=metal equilibrium constant) and variable terms that are expressed as simple power functions of proton concentration, ligand to metal ratio (LT/MeT), and ionic strength (I). The model successfully simulated the proton exchange behavior of acid-washed, Sphagnum peats over a range of 4 to 8 pH units with ionic strength differing by three orders of magnitude (I=0.001 to 0.1). Simulation of copper binding on five peat data sets and the dried biomass of Potamogeton lucens was also successful (0.94<r2<0.99). However, there was no apparent relationship between model parameters and peat characteristics. Incorporation of the SiMS model into a framework for predicting metals removals in wetlands will require more work.
Heavy metal contents and mobility of artificially inundated grasslands along River Weser, Germany
Authors: Erber C. , Felix-Henningsen P.
Published: May 2018

At the beginning of the 20th century municipal wastewater was used to fertilize grassland in the freshwater marsh of the river Weser. In 1987, 150 ha of the marsh became part of a mitigation area with artificial inundation during winter and spring. Heavy metal input may be expected from former wastewater treatment and artificial flooding nowadays. In addition, inundation may increase the availability of heavy metals that were accumulated during municipal wastewater treatment. In order to get an idea of heavy metal content and availability, the content of Cd, Cr, Cu, Ni, Pb, and Zn of the soil, the vegetation, and the input due to inundation were determined. Metal enrichment in the epipedon is evident for Cr, Cu, Pb, and Zn. Total content of Pb and Zn exceed the precaution limit. Soils treated with wastewater seems to contain more heavy metals than the ones without. Inundation causes an input of metals, but it is very low and varies in a broad range. Metal input is higher by atmospheric deposition than the one due to inundation. Degree of enrichment can be arranged in the order: atmospheric deposition > municipal wastewater >> inundation. In shallow ditch soils heavy metals are becoming more available.
Feasibility of waste stabilization pond technology for small municipalities in Colombia
Authors: Peña M.R. , Madera C.A. , Mara D.D.
Published: May 2018

The selection of any wastewater treatment technology should take into consideration both “software” and “hardware” aspects. There are contrasting opinions regarding the feasibility of waste stabilisation ponds (WSP): some emphasise their advantages while others are concerned with their high land area requirements. As with any technology, WSP are feasible under specific circumstances related to the context where they are to be implemented. In this study data were collected from three regions in Colombia (Nariño, Tolima and Valle del Cauca) in order to assess the feasibility of WSP under real conditions in a tropical country. A feasibility matrix was developed in order to organise and synthesise the information gathered. The results obtained showed that WSP are highly feasible in Tolima and Valle del Cauca due to the fact that these regions have geographical, socio-economic and technical characteristics that enhance the advantages of WSP technology. Nariño has a very mountainous topography along with other local limitations that hinder the application of WSP technology. The cost of land was not found to be a real limitation for the technology, whereas the availability of land is. Finally, the feasibility matrix may be a good planning tool at regional or national levels in order to help decision-making regarding cost-effective wastewater treatment alternatives on the basis of local conditions.
Cotreatment of sewage and septage in waste stabilization ponds
Authors: Ingallinella A.M. , Sanguinetti G. , Fernández R.G. , Strauss M. , Montangero A.
Published: May 2018

A one year study was carried out in a waste stabilization ponds system where septage and sewage are cotreated. The system consists of two septage ponds which operate alternately followed by two ponds in series which receive the combined effluent. The septage ponds also act as evaporation ponds for the accumulated sludge. The monitoring program was divided in two phases. The results of the first phase indicate that the effluent of septage ponds has an adequate quality to be discharged into the waste stabilization ponds designed to treat sewage and that is possible to use the septage ponds to dry the accumulated sludge. Further investigation is needed to find suitable post-treatment of the sludge in order to use it in agriculture.
Domestic wastewater treatment in waste stabilization ponds for irrigation in Mendoza, Argentina: policies and challenges
Authors: Vélez O.R. , Fasciolo G.E. , Bertranou A.V.
Published: May 2018

Arid areas call for imaginative water management solutions to avoid the dangers of water shortages. Growing demands of water for domestic and industrial uses decrease the availability of water for agriculture. It therefore becomes necessary to set up a policy for the use of domestic effluents. For the province of Mendoza, Argentina, with 1,500,000 inhabitants, a master plan was designed as of 1991 for the treatment of domestic effluents and subsequent disposal for irrigation. The guidelines set up by WHO for the use of wastewater in agricultural applications were taken into consideration. At present, the Province of Mendoza has available projects which are either complete, in execution or in the bidding process, entailing secondary treatment capacity with reuse of 320,000 cubic metres/day and an estimated possible irrigation area of 10,000 hectares. With this infrastructure, some strategic lines of action are recommended to establish a policy for the agricultural use of wastewater: (a) to program the use of treated wastewater to avoid discharges to irrigation flows; (b) to develop an institutional scheme for the efficient and safe use of these waters; and (c) develop scientific and technologic know-how to accompany the updated policies.
Short-term risk forecasts of heavy rainfall
Authors: Schmid W. , Mecklenburg S. , Joss J.
Published: May 2018

Methodologies for risk forecasts of severe weather hardly exist on the scale of nowcasting (0–3 hours). Here we discuss short-term risk forecasts of heavy precipitation associated with local thunderstorms. We use COTREC/RainCast: a procedure to extrapolate radar images into the near future. An error density function is defined using the estimated error of location of the extrapolated radar patterns. The radar forecast is folded (“smeared”) with the density function, leading to a probability distribution of radar intensities. An algorithm to convert the radar intensities into values of precipitation intensity provides the desired probability (or risk) of heavy rainfall at any position within the considered window in space and time. We discuss, as an example, a flood event from summer 2000.
Identification of the source of faecal pollution in contaminated rivers
Authors: Gilpin B.J. , Gregor J.E. , Savill M.G.
Published: May 2018

Identifying the source of faecal pollution is important to enable appropriate management of faecal pollution of water. Four independent assays for faecal source discrimination have been developed and implemented in our lab. These assays detect fluorescent whitening agents, faecal sterols, Bifidobacterium adolescentis and Rhodococcus coprophilus. The combination of these indicators is able to identify human derived faecal pollution in rivers containing inputs from septic tanks, municipal oxidation ponds, farmed animals and feral animals.
Options for alternative types of sewerage and treatment systems directed to improvement of the overall performance
Authors: Otterpohl R.
Published: May 2018

Technology for future houses may well include a high-tech water recycling unit that makes tapwater while people drink bottled water of high quality. There may be toilets that produce just a bag of dry fertiliser per year, hopefully without fossil energy. Rainwater infiltration is increasingly replacing storm sewers anyway. Many urban areas of the future could simply be without sewerage systems. Technical feasibility is given even today and economic feasability is coming closer by advances in membrane technology. However, there are more likely scenarios than this. One person produces about 500 litres of urine and 50 litres of faeces per year (= blackwater). The same person, produces in a range of 20,000 to over 100,000 litres of wastewater. Black- and greywater (wastewater without toilet) do have very different characteristics. If blackwater is collected separately with low dilution it can be converted to safe natural fertiliser, replacing synthetic products and preventing spreadout of pathogens and other pollutants to receiving waters. New sanitation concepts are now built in several countries as pilot projects. One example is a vacuum-biogas system for around 400 inhabitants that has been built in Lübeck, Germany. It does perform recovery of resources and energy in an urban area. This type of sanitation can serve around up to 10,000 people and can be arranged in independent modules for larger settlements. Another pilot project based on urine-sorting flush toilets (no-mix-toilets) has been built in the rural water-mill museum “Lambertsmühle” near Cologne, Germany. Urine or yellow water is collected with low dilution and can be used as fertiliser as projects in Sweden have shown – the nutrient composition suits many types of soil. Brownwater (the solids and flush from the sorting toilet) is converted to small volume by a two-chamber composting tank with a filtration system. The compost can be used as soil conditioner. These and other concepts can be economic and show new ways for the many water scarce areas around the world, too.
Using typical daily flow patterns and dry-weather scenarios for screening flow rate measurements in sewers
Authors: Piatyszek E. , Joannis C. , Aumond M.
Published: May 2018

Monitoring systems for measuring rainfall, as well as flow rates and pollutant quantities conveyed by sewers and/or discharged by stormwater overflow devices, have become a common feature in many municipal sewer services, in part spurred by recent regulatory requirements. However, the state of measurement conditions in sewer facilities does not always ensure reliable results. For this reason, it is essential that measured values be carefully screened prior to their use, since many sources of disruption capable of skewing data can be encountered. The present article describes a method for validating dry-weather data a posteriori. This method relies upon flow rate forecasts, a combination of standard daily wastewater flow profiles and an estimation of infiltration flows. Measurement results are then compared with this forecast and an appropriate series of statistical tests are run to detect all major data anomalies. A number of diagnostic rules are then applied in order to derive an initial interpretation of these anomalies and, in particular, to identify the influence of rainfall events.
Trophic relations in two lakes from the Bulgarian Black Sea coast and possibilities for their restoration
Authors: Kalchev R.K. , Pehlivanov L.Z. , Beshkova M.B.
Published: May 2018

Based on quantitative data on nutrients, light penetration, phytoplankton, zooplankton and zoobenthos obtained in the period 1992-1994 the relations between trophic levels were studied by means of statistical analysis. The two lakes are distinguished by relatively high transfer efficiency between phytoplankton and zooplankton, which depends on the size distribution among zooplankton and percentage of blue-green algae. The bottom up influence seems to prevail over the top-down influence, water surface area and phosphorus load are large, and mean depth is more than 1m. All this let us conclude that biomanipulation measures alone are not sufficient for a substantial lake restoration.
Water and wastewater in developing countries: present reality and strategy for the future
Authors: Ujang Z. , Buckley C.
Published: May 2018

This paper summarises the paper presentation sessions at the Conference, as well giving insights on the issues related to developing countries. It also discusses the present status of practice and research on water and wastewater management, and projected future scenario based not only on the papers presented in the Conference, but also on other sources. The strategy is presented to overcome many problems in developing countries such as rapid urbanization, industrialization, population growth, financial and institutional problems and, depleting water resources. The strategy consists of Integrated Urban Water Management (IUWM), cleaner industrial production, waste minimisation and financial arrangements.
Promoting sustainable industry through waste minimisation clubs
Authors: Barclay S.J. , Buckley C.A.
Published: May 2018

The concept of waste minimisation clubs was developed in the early 1990s to promote the exchange of experiences between geographically close manufacturers in the implementation of waste minimisation measures. It is a successful approach, resulting not only in a reduction in environmental impact, but also significant financial savings for the companies involved. Two pilot waste minimisation clubs were established in the province of kwaZulu Natal in South Africa in 1998 and 1999, to determine if this approach was a feasible method of promoting sustainable industrial development in South Africa. On conclusion of this project in December 2000, the 20 companies that participated in these clubs had saved a total of US$ 1.7 million, and reduced their water use and effluent discharge by over 2,400 Ml/y.
Fate of pesticides in soil in a coastal lagoon area and associated water quality impacts
Authors: Tanik A. , Gurel M. , Zeren O. , Gonenc I.E. , Arslan H. , Uysal Y. , Un Z.B. , Yalvac M.
Published: May 2018

Pesticides used on agricultural lands are among the significant diffuse sources of pollutants. They are poisons and can be particularly dangerous when misused and/or applied without care. Although certain characteristics of pesticides are well known, their final characteristics after they reach a waterbody are extremely difficult to estimate. Regarding the soil and water environment, it is necessary to conduct both a field study and laboratory analysis. Such a study has been performed in the catchment area of Dalyan Lagoon, Turkey, joining the Mediterranean Sea, that was selected as the pilot region. The input of pesticides, transport in soil and transfer to the water environment together with their probable impacts on water quality are determined by conducting detailed field surveys and water residue analyses. Within the scope of the study, the behavior and fate of pesticides both in soil and water are investigated in detail. Water residue experiments are conducted on four sets of water samples representing the seasons of the year 1999-2000 for the pre-selected 6 pesticides. Two sets of water samples (surface and bottom) are taken from the 16 stations along the lagoon channel and two lakes within the catchment area. The results and findings show the significance of the use of pesticides as they exist in the water environment around and/or slightly above the limits stated in the national current regulations except dichlorvos which presents very high values compared to its tolerance limit. Of particular interest, the results are used to enlighten the farmers and the public and increase awareness of pesticides as contaminants in valuable coastal waters.
Removal of iron and manganese by artificial destratification in a tropical climate (Upper Layang Reservoir, Malaysia)
Authors: Ismail R. , Kassim M.A. , Inman M. , Baharim N.H. , Azman S.
Published: May 2018

Environmental monitoring was carried out at Upper Layang Reservoir situated in Masai, Johor, Malaysia. The study shows that thermal stratification and natural mixing of the water column do exist in the reservoir and the level of stratification varies at different times of the year. Artificial destratification via diffused air aeration techniques was employed at the reservoir for two months. The results show that thermal stratification was eliminated after a week of continuous aeration. The concentrations of iron and to a lesser extent manganese in the water column was also reduced during the aeration period.
Co-treatment of septage in a municipal sewage treatment pond system
Authors: Kurup B. , Kurup R. , Mathew K. , Ho G.
Published: May 2018

This paper deals with the characteristics and treatment options of septage. The objective of the paper is to evaluate the effects of co-treatment of 50 MLD of septage in a sewage treatment pond system. The treatment efficiency of the pond system for BOD5 and Fecal Coliform (FC) has been estimated using a first order kinetics model. The model has predicted that the treatment pond system has a maximum capacity of 8.5 MLD and will have a reserve of 28.3% of its total capacity even after the proposed addition of 50 MLD of septage. Separation of oil and grease from septage prior to discharge into the pond system is recommended.
Characterization of wastewater and solids odors using solid phase microextraction at a large wastewater treatment plant
Authors: Kim H. , Murthy S. , McConnell L.L. , Peot C. , Ramirez M. , Strawn M.
Published: May 2018

A simple and reliable technique has been developed and used to detect odorous gases, i.e. propionic and butyric acids, carbon disulfide, dimethyl sulfide, dimethyl disulfide, and trimethylamine, emitted from various materials generated by the wastewater treatment process. The method detection limits are in the low ppb range and comparable to the odor threshold for human detection. In this study solid phase microextraction (SPME) was employed to characterize and quantify odorous compounds in the headspace over samples collected from various unit processes at the District of Columbia Wastewater Treatment Plant, Washington DC, USA. The patterns of odorous chemicals released from wastewater influent, thickened sludge, dewatered sludge and biosolids were evaluated. Volatile reduced sulfurs were more prevalent in samples collected from downstream processes and corresponded with decreased oxidation-reduction potential (ORP) conditions. Volatile fatty acids were consistently identified in the primary gravity thickeners, while trimethylamine could only be detected from biosolids after the post-liming process.
Characterisation and conditioning of Fenton sludges issued from wastewater treatment
Authors: Ramírez Zamora R.M. , Orta de Velásquez M.T. , Durán Moreno A. , Malpica de la Torre J.
Published: May 2018

Characterisation tests were conducted to determine the feasibility of land application of the sludges produced in wastewater treatment by means of Fenton's Reagent. Physicochemical and microbiological parameters of Fenton sludges were compared to the values obtained for raw alum sludges. The Fenton sludges presented preferable characteristics such as the specific resistance to filtration (SRF), metals and pathogen content (fecal and total coliforms, helminth ova, and Salmonella sp.). The SRF of the Fenton sludges (1.55 × 1013 m/kg) was 24% less than the alum sludge value (1.92 × 1013 m/kg). The concentrations of fecal coliforms (0 MPN/g TS), Salmonella sp. (0 MPN/g TS), Helminth ova (22 HH/g TS) and metals correspond to the limits for biosolids of Class B for land application of the Mexican legislation. The Fenton reagent efficiently removes most of the pathogens, considered by the norms, by means of the combined action of the different stages that constitute this process. These results exhibit the Fenton reagent as a feasible treatment for generating sludges with characteristics of biosolids of Class B for land application. The preliminary results of conditioning tests show that Fenton sludges present better dewatering characteristics with regard to the alum sludge, for a dose of cationic polymer of 1 mg/g TS.
The influence of experimental conditions on the assessment of the toxicity of 2,4-dichlorophenol to anaerobic degradative bacteria
Authors: Nitayapat N. , Watson-Craik I.A.
Published: May 2018

The toxicity of 2,4-dichlorophenol (2,4-DCP) to anaerobic bacteria in refuse cultures was investigated at two temperatures (30 and 37°C) and after two different exposure periods to the toxicants. It was shown that at 0.52mM 2,4-DCP the time of exposure of microorganisms to 2,4-DCP affected the relative activity (Av) of the production of methane. Av values at the beginning of the steady-state phase were lower than those recorded two weeks later. The incubation temperature selected also critically affected the assessment of anaerobic toxicity; at 37°C an imbalance of the activities of fermentative bacteria and acetogens with those of methanogens was observed.
Simulation of a periodic anaerobic baffled reactor (PABR): steady state and dynamic response
Authors: Stamatelatou K. , Lyberatos G.
Published: May 2018

The Periodic Anaerobic Baffled Reactor (PABR) is a novel high-rate configuration for wastewater treatment. The reactor resembles an ABR with the compartments arranged in a circular manner. The feeding and effluent points are periodically set in different compartments by proper manipulation of valves that determine the flow pattern. This way of feeding makes the reactor response oscillating and gives the PABR a great flexibility in the operation mode. A 15 litre PABR was operated on a gelatin based medium under steady and variable organic loading rate. The experimental conditions were simulated using a mathematical model whose primary feature was that each compartment was considered as a two-section tank, each section with a different biomass concentration in them. The degree of biomass accumulation was determined indirectly by the operating conditions and the reactor dynamics and was not set a-priori.
Feasibility study of mechanically disintegrated sludge and recycle in the activated-sludge process
Authors: Camacho P. , Geaugey V. , Ginestet P. , Paul E.
Published: May 2018

The action mechanisms and performances of a combined system associating activated sludge and mechanical treatment (High Pressure Homogenizer) were evaluated for urban wastewater. Discontinuous experiments showed that the energy applied at the first pass was high enough to modify the sludge particulate fraction (high COD release) but without cell lysis. The applied shear forces led to a progressive cell break up (maximal COD release 90% total COD). Continuous experiments showed less than 20% reduction in sludge production (compared to a control run under the same loading conditions YTSS = 0.35 g TSS.g−1CODremoved through the application of mechanical treatment (stress frequency = 0.2 d−1). Recycling of mechanical treated sludge to the aeration tank induced a slight increase in effluent TSS, but the biological performance seemed to be maintained. Significant improvements in sludge settling characteristics were observed.
Physical modelling of an upflow anaerobic sludge blanket reactor: near-field study
Authors: Gimenez J.R. , Nassr S.C. , Maestri R.D. , Monteggia L.O.
Published: May 2018

This paper presents a physical evaluation of an upflow anaerobic sludge blanket reactor. Specifically, the study contemplates the region influenced by the wastewater inlet jets at the bottom of the reactor, here termed the near-field area. A three-dimensional physical model of a UASB reactor in reduced scale, geometrically and dynamically correlated to a full-scale prototype was used in the evaluation. From the analysis of the major forces acting and of the physical properties investigated in the prototype, it was possible to establish non-dimensional relations that were applied to the reduced scale model, allowing the investigation of the phenomenon of interest. Tests were developed on the model to visualise the inlet flows under the buoyant effect at the bottom of the reactor, through the injection of a tracer fluid in the area with higher density, simulating the effects of the sludge bed. Based on the experimental results, it was possible to provide dimensioning criteria for the jet distribution system in UASB reactors.
Thermochemical pretreatment in the anaerobic digestion of waste activated sludge
Authors: Tanaka S. , Kamiyama K.
Published: May 2018

Effects of a thermochemical pretreatment on the anaerobic digestion of waste activated sludge (WAS) was investigated by semicontinuously-fed digesters operated at 37¡C. WAS from a return sludge line of a municipal sewage treatment plant was pretreated by autoclaving at 130°C for 5 minutes after adding 0.3g NaOH/g VSS. Solids of WAS were thermochemically solubilized to one half and then 60% or more were in totality solubilized in anaerobic digesters fed with pretreated WAS at 2-8 days of hydraulic retention times (HRT), while only 16-36% were solubilized in digesters fed with raw WAS. The adverse effect of the set temperature (130°C) on the biodegradability of protein was not found. As a result, removal rates of COD in digestion was increased from 38% to 57% at 8 days HRT by the pretreatment. A specific methane production rate in the pretreated process was three times as high as the normal process. The thermochemical pretreatment was found to be very effective to enhance biodegradability as well as solubilization of WAS in anaerobic digestion.
Biological nutrient removal wastewater treatments and sewage sludge anaerobic mesophilic digestion performances
Authors: Bolzonella D. , Innocenti L. , Cecchi F.
Published: May 2018

The paper deals with the performances of the mesophilic anaerobic digestion treatment of sewage sludge from a full scale BNR process without primary settling (nominally 300,000 PE). A relation between the activated sludge observed yields, Yobs, and the anaerobic digester performance was preliminarily found: for values of Yobs of 0.25 kgVSS/kgCOD the anaerobic digester specific gas production showed the best performances (0.22 m3/kgVSfed). This has to be confirmed with wider future studies. It was also shown the level of sludge pre-thickening to be reached for the self-sustaining warming of the digester also in wintertime. According to the energetic balance and to a comparison with an aerobic stabilisation process, it was pointed out as when a co-generation unit for heat and energy production was introduced about 3.4 kWh/PE y of energy were produced in the anaerobic digestion process. On the other hand, 4.3 kWh/PE y were spent if an aerobic stabilisation process was applied. The economic assessment, carried out on the basis of the energy balances, showed that the anaerobic digestion is always economically advantageous if compared to aerobic stabilisation processes, also for small WWTPs. According to the energetic evaluations an environmental balance was assessed, in terms of CO2 emissions. The difference between anaerobic and aerobic processes was about 5.3 kgCO2/PE y in favour of anaerobic processes application.
Removal efficiency and methanogenic activity profiles in a pilot-scale UASB reactor treating settled sewage at moderate temperatures
Authors: Seghezzo L. , Guerra R.G. , González S.M. , Trupiano A.P. , Figueroa M.E. , Cuevas C.M. , Zeeman G. , Lettinga G.
Published: May 2018

The performance of a sewage treatment system consisting of a settler followed by an Upflow Anaerobic Sludge Bed (UASB) reactor is described. Mean ambient and sewage temperature were 16.5 and 21.6°C, respectively. Total Chemical Oxygen Demand (CODt) concentration averaged 224.2 and 152.6 mg/L, for raw and settled sewage, respectively. The effluent concentration was 68.5 mgCODt/L. Total and suspended COD removal efficiencies of approximately 70 and 80%, respectively, have been observed in the system at a mean Hydraulic Retention Time (HRT) of 2 + 5 h. Maximum COD removal efficiency was achieved in the UASB reactor when upflow velocity (Vup) was 0.43 m/h (HRT = 6 h). Mean Specific Methanogenic Activity (SMA) and Volatile Suspended Solids (VSS) concentration in the granular sludge bed were 0.11 gCOD-CH4/gVSS.d and 30.0 gVSS/Lsludge, respectively. SMA was inversely related to VSS concentration, and both parameters varied along the sludge bed height. The Solids Retention Time (SRT) in the reactor was 450 days. Sludge characteristics have not been affected by changes of up to one month in Vup in the range 0.28–0.85 m/h (HRT 3–9 h). This system or two UASB reactors in series could be an alternative for sewage treatment under moderate temperature conditions.
Combining UASB technology and advanced oxidation processes (AOPs) to treat food processing wastewaters
Authors: Sigge G.O. , Britz T.J. , Fourie P.C. , Barnardt C.A. , Strydom R.
Published: May 2018

UASB treatment of fruit cannery and winery effluents was shown to be feasible. However, the treated effluents still have residual COD levels well above the legal limit of 75 mg.L−1 for direct discharge to a water system and a form of post-treatment is necessary to reduce the COD further. Ozone and ozone/hydrogen peroxide were used in combination with a granular activated carbon contacting column to assess the effectiveness as a post-treatment option for the UASB treated fruit cannery and winery effluent. Colour reduction in the effluents ranged from 66 to 90% and COD reductions of 27–55% were achieved. The combination of ozone and hydrogen peroxide gave better results than ozonation alone. Significant progress was thus made in achieving the legal limit of 75 mg.L−1.
Integrating environmental goals into urban redevelopment schemes: lessons from the Code River, Yogyakarta, Indonesia
Authors: Setiawan B.B.
Published: May 2018

The settlement along the bank of the Code River in Yogyakarta, Indonesia provides housing for a large mass of the city's poor. Its strategic location and the fact that most urban poor do not have access to land, attracts people to “illegally” settle along the bank of the river. This brings negative consequences for the environment, particularly the increasing domestic waste along the river and the annual flooding in the rainy season. While the public controversies regarding the existence of the settlement along the Code River were still not resolved, at the end of the 1980s, a group of architects, academics and community members proposed the idea of constructing a dike along the River as part of a broader settlement improvement program.

From 1991 to 1998, thousands of local people mobilized their resources and were able to construct 6,000 metres of riverside dike along the Code River. The construction of the riverside dike along the River has become an important “stimulant” that generated not only settlement improvement, but also a better treatment of river water. As all housing units located along the River are now facing the River, the River itself is considered the “front-yard”. Before the dike was constructed, the inhabitants used to treat the River as the “backyard” and therefore just throw waste into the River. They now really want to have a cleaner river, since the River is an important part of their settlement.

The settlement along the Code River presents a complex range of persistent problems with informal settlements in Indonesia; such problems are related to the issues of how to provide more affordable and adequate housing for the poor, while at the same time, to improve the water quality of the river. The project represents a good case, which shows that through a mutual partnership among stakeholders, it is possible to integrate environmental goals into urban redevelopment schemes.