bluuebunny/crossref_metadata_2025 huggingface dataset:
Steady State Kinetics of Anaerobic Downflow Stationary Fixed Film Reactors
Authors: Droste R. L. , Kennedy K. J.
Published: May 2018

Anaerobic downflow stationary fixed film reactors operated at 35°C successfully treated synthetic (sucrose based) wastewater of different concentrations at high organic loading rates and short hydraulic retention times. Based on observed relations between washout solids retention time, hydraulic retention time and loading rate, an empirical model of the process was formulated. Incorporation of the washout factor into accepted theory allowed good prediction of chemical oxygen demand removal efficiency and reactor biomass concentration.
Development of Environmental Engineering Education in Developing Countries
Authors: Ahmad Shamin
Published: May 2018

Environmental engineering education should include appropriate curricula, courses and subject materials relevant to the needs of the society. Emphasis on environmental engineering should be laid at the undergraduate level, but to develop local capabilities both for the present and the future it is essential to develop post-graduate education and training for young engineers and a continuing education programme for senior engineers. Research work should be encouraged and financed so as to develop local expertise and know-how for solving environmental engineering problems. Students should be exposed to the concept of appropriate technologies, however simple these may appear. Many of the concepts developed in advanced countries in connection with environmental protection need modification before application. These may not be directly applicable to the conditions found in the region in which many of the developing countries are located. Necessary incentives, rewards, security of job and opportunities for professional development should be provided to attract engineers to the environmental engineering profession.
Impact of Pulp and Paper Mill Wastewater on Crop and Soil
Authors: Juwarkar A. S. , Subrahmanyam P V. R.
Published: May 2018

Exhaustive field and laboratory studies were carried out for 3 years using pulp mill wastewater for crop irrigation. Anaerobically treated pulp mill wastewater used in the study falls under the class C3S1 to C4S2 and found suitable for use on coarse textured soils with salt tolerant crops. Crops like maize, barley, wheat, kenaf and sesbenia were grown successfully. Wastewater irrigation increases the soil exchangeable sodium per cent (ESP). The increase in ESP at the end of 3rd year was 30.0. However even at this level there was no appreciable decrease in yield of crops and hydraulic properties of soil. Soil equilibrium studies showed that if the pulp mill wastewater is diluted with chlorination and hypochlorite wastewater in either 4 : 1 or 3 : 1 proportions, the resulting wasteweter can be successfully used on coarse to medium textured soils without the problem of sodicity.
Prediction of Water Quality in a Future Water Supply Reservoir
Authors: Filip Anton , Cvjetkovív Miroslav
Published: May 2018

The water quality in a future water supply reservoir has been predicted using mathematical modelling based upon data measurements of water, climate, watershed characteristics, reservoir morphology and hydraulics. The following water quality parameters were modelled: water temperature, dissolved oxygen concentration, algal content, BOD5, phosphate concentration, organic sediment, etc. One and five-year periods were simulated under oligotrophic, mesotrophic and eutrophic water body assumptions to follow the development of water quality. For wet, average and dry weather conditions and most probable mesotrophic productivity development, the water body quality in time was simulated. Based on simulation results, the withdrawal conditions, as amounts and depths, were defined.
Temperature Influence on Absorption and Stripping Processes
Authors: Khudenko Boris M. , Garcia-Pastrana Alberto
Published: May 2018

The influence of temperature on mass transfer rates in gas absorption and stripping processes has been evaluated. A computer simulation analysis has been used to identify fundamental reasons for variations among temperature correction factors published in the literature. A critical molecular transfer energy was postulated and the temperature correction factor was developed based on the Maxwell distribution law. The critical energy hypothesis was experimentally validated and the critical energy of molecules crossing the gas-liquid interface of 2.6.10−13 erg was determined for both methane and oxygen in the temperature range from 5° to 75°C. The critical energy was found to be a constant value for various hydrodynamic conditions and also for water with and without surfactants. The temperature correction expression derived based on the critical energy hypothesis was compared with several published relationships. The comparison has corroborated that the developed temperature correction relationship is applicable to various gas transfer apparatus and hydrodynamic regimes.
Preliminary Investigation into the Improvement of the Biodegradability of Organic Substances in Surface Waters and Effluents through Ozonation
Authors: van Leeuwen Hans (J.)
Published: May 2018

The removal of non-biodegradable or refractory substances is expensive during both water and wastewater treatment. Tests were conducted with ozone to enhance the biodegradability of the organic substances in three different surface waters and two effluents. At low concentrations of biodegradable substances the effect of ozone could be measured by comparing the bacterial growth potential after ozonation with that in standard sodium acetate solutions while at higher concentrations the BOD to COD ratio could be used. In all the cases biodegradability could be improved substantially by ozonating to an optimum dosage where the increase was maximized. Ozonation offers an economical treatment option for certain oil-from-coal plant effluents because of the ease of oxidation and additional removal potential of organic substances by foam fractionation and biodegradation.
Evaluation of Heavy Metal Leachability from Solid Wastes
Authors: Bridle T. R. , Côté P. L. , Constable T. W. , Fraser J. L.
Published: May 2018

Future management options for residual inorganic solid wastes are likely to include land disposal. While the environmental ramifications of this option are now better understood, additional data is required to permit a thorough assessment of contaminant leachability from solid wastes. As part of this data gathering exercise, Environment Canada's Wastewater Technology Centre has been actively researching and developing test methods designed to measure intrinsic waste properties that affect contaminant leachability, such as metal solubilities and speciation. Based on this approach the leachability of heavy metals from sewage sludge, char and ash, municipal solid waste ashes, hazardous waste incinerator fly ashes, power plant ashes and a solidified synthetic waste were assessed.

The results indicate that incineration of sewage sludge produces a benign ash with most of the metals speciated as insoluble oxides or silicates. By contrast, incineration of municipal solid waste or hazardous wastes produces fly ashes exhibiting significant metal leachability. Environmentally sensitive metals such as Cd, Zn, Ni and Cu in these fly ashes were readily leachable and probably speciated as water soluble chloride salts. The intrinsic properties approach appears to be an effective method of assessing waste leachability.
The Development of Waste Water Treatment in the Finnish Pulp and Paper Industry
Authors: Luonsi A. , Junna J. , Nevalainen I.
Published: May 2018

The recent development of Finnish pulp and paper industry external wastewater treatment has created positive results by reducing the oxygen consuming load (BOD7) of the recipients. This is due to the thirteen activated sludge plants and one anaerobic reactor which have been constructed during the last four years. The target values set in the form of suspended solids (SS) and BOD7 for 1985 (400 t BOD7/d) are expected to be achieved during 1987.

Activated sludge plants have also created negative effects in the form of large amounts of surplus biological sludge and increased nutrient discharges, especially phosphorus which with reduced acute toxicity will increase the eutrophication of discharge areas. The share of activated sludge plants for the increased phosphorus discharges remains to be studied. The rapid increase started before the activated sludge plants started operation. In well operated activated sludge plant nutrient discharge is not increased.

Although the specific water consumption and specific organic loads continuously decrease in pulp and paper production the increased production and more stringent requirements for pollution control prerequisite investments for external treatment. Therefore it is the time for efficient biological treatment plant construction and before 1995 a good number of mainly activated sludge plants will be constructed, for which time target values and some alternative guidelines to pollution control have been planned but not yet officially issued.

Also requirements for CODCr, and total organic chlorine (TOCl) will be among the effluent quality criteria in the near future.

When further requirements are issued the basis must be in the requirements of the biota which it is desired to live in the discharge areas.

Much research is needed to find out how many of these requirements can be satisfied by modifications of present treatment processes. Thereafter the possibility of removing specific pollutants from the low volume fractions must be identified. The results of these studies must then be compared with the tertiary processes which can be added after the biological treatment plants which process the combined mill effluent.

The problem must be regarded as a complex one because any substance removed from the wastewater will be found either in the sludge or in the air. The harmful compounds should be returned to normal ecological circulation or to the least harmful form and location in the most suitable waste stream.
Sequential Anaerobic and Aerobic Treatment of Kraft Pulping Wastes
Authors: Qiu Rongchu , Ferguson J. F. , Benjamin M. M.
Published: May 2018

A study of sequential anaerobic and aerobic treatment was conducted with combinations of kraft evaporator condensate (KEC) and caustic extraction (CE) stage bleaching effluent. In addition to conventional measures of treatment efficiency, the transformations and removal of sulfur compounds from the KEC and changes in molecular size fraction of organic carbon and organic chlorine were measured. A large fraction of the BOD in the combined waste could be removed in the anaerobic stage at loadings of up to at least 15 kg COD/m3-d. The overall process produced an effluent with <30 mg/l BOD and SS and with varying amounts of COD, depending on the CE fraction being treated. Fractional removals of organic carbon and COD were approximately equal and were significantly greater than that of organic chlorine. Removal efficiencies were higher for the low molecular weight fraction. One third of the influent sulfur was removed as H2S gas in the anaerobic stage. The remaining sulfur was largely oxidized to sulfate in the aerobic stage, with nearly complete elimination of odors.
Anaerobic Treatment of Sulphur-Containing Effluents
Authors: Pichon M. , Rouger J. , Junet E.
Published: May 2018

A new method of defibring wood chips and producing chemi-thermomechanical pulp with significant capital and energy savings has been developed. The pollution load of bleached CTMP effluent varied between 40-60 kg/t for BOD5 and 120-210 kg/t for COD. The process includes a sulphite stage and the effluent contains sulphur compounds which are toxic to methanogenic bacteria. Studies have been conducted on anaerobic fixed bed reactors with upflow or downflow feed modes. It is necessary to progressively acclimate bacteria to increasing concentrations of sulphur compounds. Permanent functioning of reactors is possible with COD/S ratios near 10-12 where propionate concentrations are increasing. Upflow reactors are more efficient than downflow reactors, with a maximum loading rate of 3.5 kg COD/m3.day corresponding to 800 mg/l as S. With hybrid sludge bed/fixed bed reactors it is possible to enhance anaerobic treatment efficiency. A COD loading rate of 4.7 kg/m3.day can be maintained with a residence time of 2 days and a pollution load removal efficiency of 45% for COD (55% with complementary oxidation) and 70% for BOD5. The economics of effluent treatment give an investment cost of about 20 US$/ADt for the activated sludge process and 12.5 US$/ADt for anaerobic fixed bed treatment.
The Fate of Spent Bleach Liquor Material in Receiving Waters: Characterization of Chloroorganics in Sediments
Authors: de Sousa Filipe , Strömberg Lars M. , Kringstad Knut P.
Published: May 2018

Sediments collected at various distances from pulp mills producing bleached chemical pulp were characterized with respect to the presence of chlorinated material extractable by hexane/isopropanol. Also the presence of chlorinated high molecular weight material from spent bleach liquors was investigated by oxidative degradation. The results show that the major part of the hexane/isopropanol soluble material in sediments differs from that in spent bleach liquors. This suggests that this material originates from sources other than spent bleach liquors or is formed by chemical and/or biological transformations of such material. However, the sediments do contain small quantities of chlorinated phenolic compounds and high molecular weight material originating from spent bleach liquors.
Aquifer Thermal Energy Storage in Finland
Authors: Iihola H. , Ala-Peijari T. , Seppänen H.
Published: May 2018

The rapid changes and crises in the field of energy during the 1970s and 1980s have forced us to examine the use of energy more critically and to look for new ideas. Seasonal aquifer thermal energy storage (T < 100°C) on a large scale is one of the grey areas which have not yet been extensively explored. However, projects are currently underway in a dozen countries. In Finland there have been three demonstration projects from 1974 to 1987. International co-operation under the auspices of the International Energy Agency, Annex VI, ‘Environmental and Chemical Aspects of Thermal Energy Storage in Aquifers and Research and Development of Water Treatment Methods' started in 1987. The research being undertaken in 8 countries includes several elements fundamental to hydrochemistry and biochemistry.
Clogging Problems in Groundwater Heat Pump Systems in Sweden
Authors: Lindblad-Påsse Annika
Published: May 2018

A number of groundwater heat pump systems have been investigated to determine the extent of problems caused by the chemistry of the groundwater used. The main purpose was to investigate sites using iron rich groundwater. Fifteen facilities were studied regularly for three years. Ten of these facilities had some kind of problem caused by iron precipitation. Four of the sites were rebuilt because of severe plugging due to iron sludge in wells, pumps and pipes. In all facilities with severe problems, iron bacteria were found. Low redox potential, indicated by hydrogen sulphide in the groundwater, seems to protect from iron bacteria. In some of the systems using groundwater with H2S the problems were corrosion and sludge formation caused by sulphur oxidizing bacteria. Rapid clogging was caused by aeration of the groundwater due to improper design of the system. Knowledge of the water composition, design of the systems to minimize aeration, and control of clogging turned out to be important factors to maintain operation safety.
Biological Treatment of Groundwater in Basins with Floating Filters–II. The Role of Microorganisms in Floating Filters
Authors: Seppänen Harri
Published: May 2018

The role of certain types of bacteria is quite decisive in the formation of iron and manganese precipitates. Bacteria and other organisms participate in the precipitation of soluble iron and manganese in many different ways. The production of hydrogen peroxide seems to be an important phase in the formation of the precipitates. Bacteria produce hydrogen peroxide as an intermediate or an end product of metabolic processes (Gorlenko etal., 1983).

Iron and manganese bacteria are typical gradient organisms, growing in a sharp gradient between oxidized and reduced environments. Iron precipitating types are oligotrophic and manganese precipitating types need higher concentrations of organic compounds. Manganese precipitating bacteria are eutrophic.

Iron bacteria are sessile, and grow attached to the solid surfaces of filter media. Typical iron and manganese precipitating bacteria in groundwaters are Gallionella, Leptothrix, and Metallogenium.
Biological Groundwater Denitrification: Laboratory Studies
Authors: Soares M. I. M. , Belkin S. , Abeliovich A.
Published: May 2018

Laboratory denitrification studies were conducted in a sand column using sucrose as a biodegradable carbon source. The denitrification capacity of the system was followed for more than one year. Column efficiency was dependent on the flow rate and on the carbon to nitrogen ratio in the treated water. After a few months of operation, visible accumulation of gas in the active zone was accompanied by a marked decrease in column permeability. Vacuum treatment restored permeability to its original level; only partial recovery was achieved by simply allowing the slow natural release of gas. He suggest that under the conditions tested, clogging resulted from the accumulation of microbiologically produced gas.
In situ Biological Groundwater Denitrification: Concepts and Preliminary Field Tests
Authors: Mercado A. , Libhaber M. , Soares M. I. M.
Published: May 2018

High nitrate concentration presents the main groundwater quality problem of the Israeli coastal aquifer which supplies 25% of the total water consumption of the country. In about 50% of the coastal wells nitrate concentration exceeds 45 mg/l and in 18% of the wells nitrate concentration is above the maximum permissible concentration of the new Israeli standard - 70 mg/l. Although several protection measures, mainly administrative, were introduced, their impact would be pronounced only after 1-3 decades, thus nitrate removal technologies should be introduced as a mid-term solution. Pilot plant experiments were conducted in order to develop, demonstrate and compare various in-situ schemes for nitrate removal from groundwater by biological denitrification. Activities were focused towards two schemes: (i) Denitrification in a dual purpose (recharge-pumping) well and (ii) Substrate injection through a battery of small diameter wells surrounding a central production well (the “Daisy” system). Experiments related to the first scheme indicate that, though nitrate content can be reduced almost to zero, its economic feasibility seems to be unfavorable because of operational difficulties and the apparent requirements for costly supplementary treatment. Experiments related to the “Daisy” scheme demonstrated a nitrate removal efficiency of approximately 10%. Considering the fact that only one injection well of the three drilled functioned properly, the above mentioned nitrate removal represents the efficiency of a single injection well. It is anticipated that further experiments with the “Daisy” system consisting of 5-6 injection wells would result in a significant nitrate reduction.
In situ Denitrification of Drinking Water
Authors: Janda V. , Rudovský J. , Wanner J. , Marha K.
Published: May 2018

Pilot-plant and full scale studies of the in-situ biological denitrification of drinking water form the subject of this paper. Ethyl alcohol as a source of organic carbon was used in both cases. Good results were obtained during the pilot-plant study. The full-scale experiment was carried out as a system of four injection wells and one central collection well. Promising results were obtained when diluting water was recirculated into the injection wells to improve mixing of substrate in ground water. The efficiency of nitrate removal was about 50%.
Particles Found in Clogging Layers of Wastewater Infiltration Systems May Cause Reduction in Infiltration Rate and Enhance Phosphorus Adsorption
Authors: Jenssen P. D. , Krogstad T.
Published: May 2018

Infiltration rate can show a long term reduction over time in wastewater infiltration systems and it has been shown that soil adsorption of phosphorus from wastewater is higher than adsorption isotherms predict. These phenomena can partly be explained by particles found in the clogging layer of waste-water infiltration systems.
Activated Sludge Treatment of Wastewater from a Nylon 6 Manufacturing Plant
Authors: Kageyama Masao , Tomita Kosuke
Published: May 2018

The activated sludge treatment of wastewater containing ɛ-caprolactam from a Nylon 6 manufacturing plant was investigated by basic studies and operation of a full-scale treatment plant. Activated sludges were obtained from several municipal and industrial wastewater sources, or were prepared by mixing ɛ-caprolactam-utilizing bacteria (Bacillus sp. and Achromobacter sp.) with a municipal activated sludge. However, bulking phenomena were soon observed in the acclimatization of ordinary activated sludges, even when started from a very low concentration of ɛ-caprolactam. On the other hand, the activated sludge synthesized from ɛ-caprolactam-utilizing bacteria showed better results as regards sludge volume index (SVI), BOD removal, and transparency of treated water.

Wastewater from the Nylon 6 manufacturing plant, which contained ɛ-caprolactam, was treated by this synthesized activated sludge in a bench-scale apparatus consisting of a 4 m3 aeration basin and a 1.4 m3 sedimentation basin. The optimum BOD loading was estimated to be 0.35-0.40 kg BOD/kg MLSS/day for this wastewater. Production of excess activated sludge was 10% of the BOD loaded. In 1974, based on this preliminary experiment, a wastewater treatment facility consisting of a 2,500 m3 aeration basin and a 1,250 m3 sedimentation basin was constructed near the Uji Nylon 6 manufacturing plant (Unitika Ltd), to treat 5,000 m3 of wastewater (BOD 300-400 mg/l) per day. The treatment plant operates successfully, producing treated water with a BOD below 10 mg/l.
An Unexpected Odour Problem in the Biological Treatment of Chemical Wastewater
Authors: Dijkstra F. , Plum M. , Geerdes A.
Published: May 2018

DSM, a large chemical company in the Netherlands, operates a plant for the biological treatment of the wastewater of about 35 production plants (organic and inorganic chemicals). A special feature of this biotreatment plant is complete nitrification of Kjeldahl-nitrogen, in combination with denitrification. Experiences with this installation are reported. A serious odour problem has arisen due to the presence of traces of a tellurium-containing catalyst from one of the plants. An organic tellurium compound with a very low odour threshold is produced in the wastewater treatment plant, mainly under anoxic, dentrifying conditions. Experimental results on the origin of the problem are reported, and a solution is given.
Use of Toxicity Tests for Assessing the Effluent of the South Petrochemical Complex Treatment System
Authors: Teixeira R. L. , Ferreira E. S.
Published: May 2018

SITEL has decided to expand their wastewater testing and environmental monitoring program to include bioassays. This action is necessary because physical and chemical data alone are not sufficient for the evaluation of treatment efficiencies and for the assessment of the potential effects of disposal practices on receiving water and associated biota. Regarding this purpose an additional program including two short-term toxicity tests with eggs and larvae of Pimephalespromelas was implemented. The first results obtained suggest good performance of the treatment system concerning reduction of toxicity. In the tertiary stage of treatment the toxicity tests were shown to be more effective than physical and chemical analysis.
SITEL: A Successful Petrochemical Wastewater Treatment System
Authors: Goettems Ellen M. P. , Simon Zeno , Baldasso Mario L. , Ferreira Edson S.
Published: May 2018

SITEL, Integrated Wastewater Treatment System of South Petrochemical Complex, has been processing liquid wastes from this industrial area since November 1982. The Complex consists of an olefins plant and some second-generation plants that produce mainly thermoplastic resins. In this paper a comprehensive appraisal is presented of the operation of SITEL during the years 1985-1986. Data on the raw effluents produced by the individual contributors are presented, together with information on removal efficiencies of all parameters monitored throughout the different units and phases of treatment. A comparison between design characteristics and actual operational data of the system is also provided.

Attention is drawn to results of bioassays and other peculiar methods of ecological and biological monitoring adopted at SITEL. This special monitoring routine shows that the tertiary treatment phase (consisting of eight waste stabilization ponds) accomplishes reduction of sublethal effects from the effluent that are not detected by conventional physico-chemical analyses. Data on priority pollutants are also presented, showing a reduction of the contents of most of these contaminants by the secondary (activated sludge) phase of treatment.

Since the final effluent is applied on land, data on quality of underground water are also presented together with data on the quality of the nearest river. These are not appreciably altered by the final effluent from SITEL, except for certain parameters associated with dissolved ions that are mobile in soil, i.e., Na, Cl−, SO4−− and TDS.

Comments on interesting cases of negative removal efficiencies are presented. Most of them can be ascribed to unique characteristics of the treatment system. Comparisons between operating costs of SITEL and data provided by other authors are also made. It is concluded that these costs are not high and can be reduced if more industries are installed in the South Petrochemical Complex and connected to SITEL. As a whole, the plant has been operating successfully with a high benefit/cost relationship.
Operating Experience with Biological Nutrient Removal at the Johannesburg Bushkoppie Works
Authors: Pitman A. R. , Trim B. C. , van Dalsen L.
Published: May 2018

Various factors are important for the successful performance of biological nutrient removal processes. This paper reviews the performance of the new Bushkoppie Plant in Johannesburg in relation to other nutrient removal plants in the city and from these experiences, highlights important aspects to be considered in the design and operation of these plants. These are substrate quality, denitrification, sludge settleability, aeration, process configuration and sludge handling and disposal.
Metro Chicago's Sludge Management Plan
Authors: Kirie James C. , Majewski Gloria , Ryan John M.
Published: May 2018

The present sludge management plan of the Metropolitan Sanitary District of Greater Chicago is referred to as the “Dry Solids Program.” This nrogram meets the criteria for being environmentally acceptable and cost-effective. The program includes several unique unit operations in what would otherwise be considered a conventional sludge processing train that consists of thickening, stabilization, dewatering, and drying. Among the unique unit operations are thickening the raw sludge by centrifugation, thickening ana dewatering the stabilized sludge in centrifuges or lagoons, atmospheric air drying of the dewatered sludge on paved surfaces, and continuous use of mechanical agitating equipment during the drying season to enhance the atmospheric drying rate of the sludge. Final disposal of air-dried sludge is administered under a “Controlled Distribution” permit issued by the Illinois Environmental Protection Agency. End usages of the air-dried sludge include: landfill cover; soil conditioner/fertilizer for sod farms, tree nurseries, golf courses, and highway right-of-ways; and land reclamation work.
Design, Testing and Operation of Grit Chambers with Hydraulic Roll
Authors: Gruber Y. , Farchill D. , Goldstein M.
Published: May 2018

The Soreq biological treatment plant has been recently brought into operation, after a comprehensive start-up and testing program. The plant's preliminary treatment facilities include four grit chambers 40 m long, equipped for both grit removal and scum skimming.

The variable energy input required to control the deposition of the grit and the floating of the scum, is provided by a hydraulic jet system, using pumped recycled wastewater to generate the necessary motive power. The basic concept in designing grit chambers equipped with a hydraulic jet system, instead of a bubble aeration system, is to avoid the release of noxious odours and corrosive gases which are often associated with the conventional aerated grit chambers.

Experiments were conducted on a hydraulic model of the grit chamber to develop the necessary design criteria for the full scale jet system. During the initial start-up program of the Soreq plant, the grit chambers and the related equipment were tested with clear water, and the actual transversal velocities were measured through a range of simulated operating conditions.

This paper summarizes the hydraulic model test results, the upscaling approach used for design of the prototype system, and the on-site full-scale tests with clear water. A follow-up program under actual operating conditions is now in progress to establish the variable parameters for optimal operation of the hydraulically powered grit chambers with wastewater.
What Advantages Can Be Expected from the Acceptance of Variable Quality Standards for Sewage Treatment Effluents?
Authors: Bernard Jacques
Published: May 2018

The flow and the water quality of the rivers vary throughout the year. Very frequently the environment protection authorities set up a quality objective for the river water and this mini mum quality level is constant. So, it wou1d seem possible to accept variable quality standards for plant effluents. A first approach of the problem,by a small French task group,based on three actual cases leads to the provisory conclusion that such a regulation is suitable and presents economical benefit only in some very limit ed cases.
Davyhulme Sewage Treatment Works Effective Energy Utilisation
Authors: Jones A. P. , Counsell N.
Published: May 2018

The paper offers a brief description of Davyhulme Sewage Treatment Works, which serves the City of Manchester.

The Works, the largest in North West Water area, is regionally of strategic importance. It influences Authority policy in sludge disposal and has a significant environmental impact on the Mersey Estuary.

During the period 1983/1985 a new anaerobic digestion plant was constructed at the works. In conjunction with this scheme, an energy saving project was designed to fully utilise all the gas produced and generate electricity. The plant uses spark ignition engines with the provision of waste heat utilisation, and operates in parallel with existing dual fuel engines.

The paper describes this plant and details operating experiences over the first year and a half, exploring how energy has been saved to the point where the works can be almost self sufficient in electricity production.

It is now intended to extend the scheme further, so that the works becomes a nett exporter of electricity, and the paper outlines the design of this second stage.

Total power savings of some ₤700,000 pa have already been achieved and it is hoped to increase this to over ₤1,000,000 pa on completion of the second stage.
The Use of Sludge and Sulphide to Remove Heavy Metals from Sewages before Activated Sludge Treatment
Authors: Licskó István
Published: May 2018

The removal of five different heavy metals (Zn2+, Cu2+, Cr 3+,Cd 2+ and Ni 2+) was studied under laboratory conditions using close to neutral mixed municipal wastewater. 90 to 95 % of the Zn2+, Cu2+ and Cr3+ was found to precipitate within 5 min and to become removable by simple phase separation. The Cd2+ and Ni2+, however, refused to precipitate, unless a “reagent” (sulphide ion, primary and activated sludge) was added. In the presence of these, cadmium was normally more readily removed than nickel. Both heavy metals were removed most efficiently, when primary sludge (1.4 g.dm−3) and sulphide ions (5-15 mg.dm−3) were added in combination. As demonstrated by plant trials, this treatment would cause the heavy metals to precipitate and settle out in the primary settling tank, so that traces only would enter the aeration tank.The excess sludge would thus contain trace quantities of heavy metals only, removing an obstacle to land disposal. The introduction of this unit operation has been estimated to increase the overall construction and costs of sewage and sludge treatment by 2.3 %, the unit costs of treatment by 6 %.
Media Evaluation and Behavior of Clostridium Perfringens as an Adjunct Indicator of Quality in Shellfish Growing Areas
Authors: Abeyta C. , Wekell M. M. , Kaysner C. A. , Stott R. F. , Raghubeer E. V. , Matches J. R. , Peeler J. T.
Published: May 2018

In numerous studies of estuaries of the West Coast of the United States, we have recovered C.perfringens, total and fecal coliforms, and fecal streptococci from shellfish, sediments and water. In some areas closed to shellfish harvest and known to be subject to fecal contamination, C.perfrinqens were recovered regularly from shellfish and sediments. For example, in one estuary, prior to sampling, a local sewage treatment plant (STP) with a design capacity of 1 million gallons per day (MGD) was receiving high flows of raw sewage of 3.02 MGD. This resulted in an overflow or bypass of raw sewage into the estuary. Fecal coliform and fecal streptococci levels measured in impacted oysters showed an increase during the initial stages of the bypass and decreased to baseline levels by the 5th day of sampling. C.perfringens levels increased from 36 MPN/100 g and reached maximum levels in oysters (4600 MPN/100 g) on the 6th day when the sewage flow was returning to normal, but still over capacity (1.8 MGD) and sewage was being discharged into the bay. At this time, fecal coliforms and fecal streptococci counts were near baseline levels (120 and 50 organisms/100 g respectively). Therefore, at the later stages of the sewage bypass, C.perfrinqens was a useful indicator of fecal contamination in oysters.

The most recent and promising method for the enumeration of C.perfrinqens in all types of environmental samples is the Iron Milk Method (IMM). The method has been tested with water, marine and freshwater sediments, soil, fish gut contents and foods, and has been shown to enumerate C.perfrinqens without the need for confirmation. The IMM uses a 3 tube MPN procedure with each tube containing 10 ml of homogenized milk plus 0.2 g iron powder per tube. Inoculated tubes are incubated for 16-18 hrs at 45 °C. The presence of the classical stormy fermentation signifies a positive tube. Numbers of C.perfrinqens in samples are rapidly measured.
The Role of Estuarine Modeling in Nutrient Control
Authors: Lung Wu-Seng
Published: May 2018

Two case studies are presented to demonstrate how estuarine water quality models can be used in planning eutrophication control. In the first study, a steady-state model is used to assess the impact of point source phosphorus reduction on the phytoplankton biomass in the upper James Estuary in Virginia during the summer months. The modeling results indicate that phosphorus is in ample supply to support the phytoplankton growth in the system. However, substantial reduction of loads by phosphorus removal at the wastewater treatment plants would lead to a phosphorus limiting condition thereby lowering the phytoplankton biomass levels. In the second study, a time-variable model is developed to investigate the potential of blue-green algal (Microcystis) blooms in the Neuse Estuary in North Carolina. More specifically, the model is designed to address two management questions. First, recognizing that high nonpoint nitrogen loads in the spring months would lead to a proliferation of non-nitrogen fixing blue-green genera, should parallel control of nitrogen be considered? Second, in light of the potential for algae species dominance to shift, is control of nitrogen fixing blue-green algal blooms possible? Based on the modeling calibration results using data from 1983, 1984 and 1985 under different hydrologic conditions, freshwater flow to the estuary is found to be a key factor in controlling blue-green algal blooms in the Neuse Estuary.
Field Observation and Simulation of Sediment Resuspension in a Shallow Lake
Authors: Otsubo K. , Muraoka K.
Published: May 2018

The dispersion and resuspension of sediments in Takahamairi Bay basin of Lake Kasumigaura were studied by means of field research and numerical simulation. The field data on wind direction and velocity, lake current, water wave, and turbidity were shown. Based on these results, we discuss how precipitated sediments were resuspended in this shallow lake. To predict the turbidity and the depth of bed erosion, a simulation model was established for this lake. The calculated turbidity showed good agreement with the field data. According to the simulated results, the turbidity reaches 200 ppm, and the bed is eroded several millimeters deep when the wind velocity exceeds 12 m/s in the lake.
The Role of Modelling in the Control of Seawater Pollution
Authors: Horie Takeshi
Published: May 2018

A feasibility study of seawater improvement projects in selected bays where seawater is highly polluted by organic substances is being conducted. The study includes field surveys in these bays of, for example, seawater quality, sediment characteristics, sediment release rate, sediment settling rate, organism growth rates, and biological activity. Numerical analysis of the situation is also being conducted, using a set of mathematical models. A water quality prediction model was formulated on the basis of phosphorus cycling between seawater, phytoplankton, and sediment. The results of the simulation predicted that the effect of seawater quality improvement would be unexpectedly small, because of dilution due to advection and dispersion by seawater circulation. However, in the field, ecological conditions seem to be significantly improved, given that the number of benthic species and the populations of these species increase on treated sediment, even though the improvement of water quality is less than expected. Based on these results, the author discusses the role of the numerical model and gives examples of its application in predicting the environmental improvement due to seawater quality improvement.
The Efficiency and Relevance of Different Concentration Methods for the Analysis of Off-Flavours in Water
Authors: Lundgren B. V. , Borén H. , Grimvall A. , Sävenhed R. , Wigilius B.
Published: May 2018

The efficiency of four different concentration methods (stripping with and without addition of salt, XAD-2 adsorption and dichloromethane extraction) for the enrichment of off-flavour compounds in treated and untreated surface water has been evaluated by gas Chromatographic sniffing and by sensory analysis of the concentrated extracts. In general, the extracts obtained by dichloromethane extraction and XAD-2 adsorption contained a larger number of off-flavour compounds than the stripping extracts. Experiments in which the extracts from stripping and dichloromethane extraction were dissolved in odourless water showed that the original odour quality of the water could normally be re-created by both methods. However, for certain surface water samples, the original odour may be re-created from extracts obtained by solvent extraction but not from corresponding stripping extracts, proving that the choice of concentration method can be important. Fractionation of extracts by preparative gas chromatography followed by dissolving of the resulting fractions in odourless water, was found to be a powerful technique for isolating the organic compounds causing the off-flavour of a water sample.
Effects of Interactions within a Three-Membered Microbial Community on the Kinetics of Dual Substrate Removal in Continuous Culture
Authors: Grady C. P. Leslie , Lu Yunn-Tzer
Published: May 2018

A bacterial community containing a generalist and two specialists was grown in continuous culture at three dilution rates on a feed containing L-lysine and 2-chlorophenol (2-CP) as the only carbon sources. The lysine degrading specialist maintained stable but oscillatory numbers whereas the generalist declined in number throughout each experiment. The 2-CP degrading specialist initially washed out of the culture, but then increased in number over time. No changes in the effluent lysine and 2-CP concentrations could be correlated with the changes in the community structure.
Bacterial Transport in Fractured Rock – A Field-Scale Tracer Test at the Chalk River Nuclear Laboratories
Authors: Champ D. R. , Schroeter J.
Published: May 2018

The potential for transport of bacteria by groundwater in fractured crystalline rock was assessed in a series of field-scale tracer tests. The breakthrough curves for injected Escherichla coll and “non-reactive” particle tracers were compared with those for conservative inorganic and radioactive tracers. Rapid transport, relative to the conservative tracers, of both bacteria and non-reactive particles was observed. The first appearance of both was with, or slightly before, the conservative tracers for water movement. Removal of the bacteria and particles by filtration processes occurred and was quantified through the calculation of filter factors. The filtration process in this fracture system is similar to that found in a gravel aquifer. From the results we can conclude that particulate contaminants can be very rapidly transported in fracture systems and that continuing sources of contamination could lead to relatively high local concentrations of particulate contaminants compared with the average at any given distance from the source. It was also concluded that the use of traditional conservative tracers, for water movement, to assess the potential for movement of particulate contaminants could lead to significant underestimates of exposure to particulate contaminants due to consumption of water from water recovery wells located in fractured media.
Utilization of Immobilized-Bacteria to Degrade Aromatic Compounds Common to Wood-Treatment Wastewaters
Authors: O'Reilly Kirk T. , Kadakia Rakesh , Korus Roger A. , Crawford Ronald L.
Published: May 2018

The utilization of immobilized bacterial cells to remove toxic compounds from contaminated water is reviewed. A microbial biofilm capable of degrading the wood preservative pentachlorophenol (PCP) was developed in an aquatic system exposed to the biocide. The ability of the biofilm to function in a variety of bioreactors was tested. PCP and other aromatic compounds were degraded in the reactors. Large-scale bioreactors developed following these initial studies are currently in operation decontaminating water associated with wood-treatment facilities.

Pure cultures of bacteria capable of degrading PCP or p-cresol have been immobilized in calcium alginate. Complete degradation of the target compounds occurred in both batch and continuous bioreactors. Studies indicate that it should be possible to customize bioreactors for decontamination of specific waste streams by immobilizing the proper bacteria.
Drinking Water Microbiology Research in the United States: An Overview of the Past Decade
Authors: Reasoner Donald J.
Published: May 2018

The passage of the Safe Drinking Water Act (SDWA) in 1974 (Public Law 93-523) significantly influenced microbiological, chemical and engineering research on drinking water quality in the United States. Microbiological quality research during the past 10 years encompassed the two basic areas of treatment and distribution. Much of the treatment research focused on generation of data to support the evaluation of turbidity and coliform maximum contaminant levels (MCLs) for the Interim Primary Drinking Water Standards. Major effort was also directed toward disinfection research on enteric viruses, pathogenic bacteria and the protozoan pathogen, Giardialamblia. Basic distribution system studies examined the occurrence of heterotrophic bacterial numbers and types in treated and untreated distribution waters, and coliform occurrence and colonization problems. Methodology developments bridged both treatment and distribution, and included enteric virus detection methods, injured ooliform recovery, heterotrophic bacteria enumeration, and Giardia cyst detection. Knowledge gained from the research efforts of the past deoade has resulted in new challenges and opportunities to improve drinking water quality.
Instrumental Detection of Coliform Bacteria for Industrial Control of Drinking Water Quality
Authors: Bernard Cl , Leglise J. P. , Colin F. , Bouchinet J.
Published: May 2018

Ensuring the sanitary quality of the potable water supply requires continuous control. Traditionally germs indicating faecal contamination are detected as it is difficult to isolate the enumerate pathogen organisms. The purpose of this report is to describe the steps we have taken to manufacture an on-site locatable automatic device "E. Colimetre" as from the definition of requirements. This device can detect one thermoresistant bacterium with a response time below 10 h. The article describes the device and the evaluation procedures.
The Effect of Controlled pH on the Development of Rosette-Forming Bacteria in Axenic Culture and Bulking Activated Sludge
Authors: Unz R. F. , Williams T. M.
Published: May 2018

An infestation of a rosette-forming microorganism, with morphological characteristics bearing some resemblance to Eikelboom type 021N and Thiothrix spp., occurred in the activated sludge process of a paper and pulp manufacturing facility during the autumn of 1986. The microorganism could not be eliminated by periodic acid-shocking of the mixed liquor with sulfuric acid, however, exposure of the mixed liquor solids for 10 days at controlled pH (circum pH 5.5) brought almost immediate lowering of the sludge volume index and effluent suspended solids to levels observed in normal operations. The bulking correction technique required no purchase of special chemicals in that the procedure was a mere modification of the liming step normally employed to bring the natural pH of the wastewater (pH 3) to a level suitable for the practice of biological treatment.