bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of Biofiltration for Removal of Natural Organic Matter to Achieve Biologically Stable Drinking Water
Authors: Hozalski R. M. , Goel S. , Bouwer E. J.
Published: May 2018

The presence of organic carbon in raw drinking waters can cause problems such as trihalomethane formation during disinfection with chlorine, regrowth of bacteria in the distribution system and reduced GAC adsorber bed life. This research concerns biofiltration for the removal of organic matter from drinking water sources. A major objective of this research is to examine how differences in the source and composition of the natural organic matter relate to the biodegradability of the natural organic matter and influence biofiltration effectiveness. Most of the organic matter in Dismal Swamp water, one of the four sources of organic matter to be evaluated in this study, has an apparent molecular weight in the 3-10 K range and the < 0.5 K range as shown by an apparent molecular weight analysis using ultrafiltration. Aerobic batch biodegradation experiments were performed using Dismal Swamp water ozonated at a dose of 1 mg O3/mg TOC. A 30 % reduction in total organic carbon over an 11-day incubation period was observed.
Continuous Biological Phosphorus Removal in a Biofilm Reactor
Authors: Gonçalves R. F. , Rogalla F.
Published: May 2018

Mechanisms for biological phosphorus removal from wastewaters in an upflow granular aerated filter are evaluated. The feasibility of excess phosphorus uptake on fixed bacteria is demonstrated on pilot scale and the limiting parameters are established. The influence of the duration of anaerobic and aerobic states and of substrate loadings on phosphorus removal is verified, as well as the impact of alternating aeration on nitrification. Because bacteria are attached, hydraulic retention time of biomass and water can be separated and the exposure of bacteria to anaerobic or aerated conditions can be optimised.
Biocarbone Aerated Filters - Ten Years After: Past, Present, and Plenty of Potential
Authors: Rogalla F. , Sibony J.
Published: May 2018

About ten years ago, the first full scale Biocarbone aerated filter went into service in Soissons (France) for a capacity of 40 000 population equivalents. This compact wastewater treatment system combines aerobic biodegradation and filtration in one unit, eliminating the need for clarifiers and achieving high removal rates through fixed biomass. Since, a number of independent investigations have been performed to establish dimensioning criteria and process performance. This article summarises the reports of the US EPA, the Japanese JSWA, and the British WRC, as well as experiences acquired by cities and water authorities.

In pilot and demonstration scale, reactor kinetics, sludge production and energy consumption was measured. Most reports agree on removal rates up to 4 kg BOD/m3 d or nitrification rates around 0.6 kg N/m3 d. Sludge yields ranged consistently around 0.8 kg SS / kg BOD removed, but oxygen transfer measurements varied from 7 % to 15 %. Full scale experience confirms these values, and operation results from large plants in North America are given.

Several examples of using the Biocarbone process for low pollution residuals are demonstrated, including plants in Britain, Denmark and Switzerland. As tertiary installation fed with clarified secondary effluent, final residuals below 1 mg/l N-NH4 and 5 mg/l for SS and BOD can be achieved in a hydraulic detention time around one hour. On settled sewage, two hours detention time results in advanced secondary effluent quality below 5 mg/l N-NH4 and around 10 mg/l for BOD and SS. If an anoxic reactor is added, total nitrogen residuals below 10 mg/l can be achieved in about three and a half hours.
Cavitation-Induced Degradation of Phenol by Ultrasound
Authors: Okouchi S. , Nojima O. , Arai T.
Published: May 2018

Aqueous solution of phenol was irradiated with ultrasonic waves of sufficient intensity to induce cavitation. The phenol was exponentially degradated, because of the formation of reactive species produced by water decomposition and reaction with water and oxygen. The degradation pathway for phenol was similar to that of the phenol oxidation with ozone.
Evaluation of Biodegradability of Starch-Based Plastics
Authors: Ndon U. J. , Levine A. D. , Bradley B. S.
Published: May 2018

Four commercially produced starch based plastics manufactured by the addition of starch to polyethylene matrix were tested in the laboratory to measure their biodegradability under both aerobic and anaerobic conditions. Pure starch was also tested under identical conditions to compare rates and extent of degradation of starch in the plastics to that of pure starch. Plastics surface properties and weight average molecular weights were observed before and after biological tests using Scanning Electron Microscopy (SEM), and High-Temperature Gel-Permeation-liquid Chromatography (HT-GPC) (Lee et al., 1991) respectively. Degradation rates and total percentage of carbon conversion were higher under aerobic tests as compared to tests under anaerobic conditions. Overall carbon conversion in starch based plastics was less than that of pure starch. Surface analysis of the plastics indicated removal of some starch granules from the polyethylene matrix. Significant changes did not occur in the average molecular weights of the plastics from HT-GPC tests which indicated no degradation of the polyethylene matrix.
Evaluation of South African Raw and Drinking Water Supplies for Volatile Organic Complexes Potentially Hazardous to Human Health
Authors: Meintjies E. , Maharaj V.
Published: May 2018

Raw and drinking water grab samples were collected throughout the province of Transvaal, Republic of South Africa, during a 2.5-year period from September 1988 to January 1991. Conductivity, pH and UV absorbance were recorded on all samples throughout the study period while trihalomethanes were measured on drinking water samples only. Results were compared to recommended and maximum allowable limits for drinking water. In addition, extracts of the water samples were analysed by gas chromatography with flame ionization detection for volatile organic complexes. All samples revealed a complex mixture of organic complexes at very low concentration. Thirty six organic compounds, which can be classified into 5 categories, were positively identified by mass spectrometry. The most frequently occurring compounds were phthalate esters and acyclic hydrocarbons. The low concentration levels at which each of the identified substances occurred are unlikely to constitute a health hazard.
Pathogen Reduction Capabilities of Freeze/Thaw Sludge Conditioning
Authors: Sanin D. F. , Vesilind P. A. , Martel J. J.
Published: May 2018

Freeze/thaw conditioning of sludges has been shown to be an effective and economical method of sludge dewatering especially for areas where natural freezing is possible. Freeze treatment dehydrates the sludge particles by freezing the water associated to the floc and upon thawing an easily drainable granular type of material is obtained. The solid content of the freeze/thawed sludge from specially designed freezing beds ranges from 30% to as high as 60%.

Pathogen reduction capacity of freeze/thaw conditioning has not been evaluated. The purpose of this study is to determine the variables affecting the pathogen reduction in freeze/thaw sludge conditioning. Previous research has shown that freezing rate, time in the frozen state, and temperature all influence the condition of the freeze/thawed sludge, and these are chosen to be the independent variables of the research. The three microorganisms- salmonella, fecal coliforms and plaque forming units for viruses-are chosen to be the dependent variables, since they best represent the other pathogenic microorganisms.

Three different rates, four different temperatures and three different times of freezing are tested for their effects on the reduction of the three selected microorganisms.

Results indicate that all of the parameters, time, rate and temperature of freezing have significant effects on the reduction of the indicator microorganisms.
Comparison of Yields and Decay Rates for a Biological Nutrient Removal Process and a Conventional Activated Sludge Process
Authors: McClintock S. A. , Pattarkine V. M. , Randall C. W.
Published: May 2018

Two pilot-scale activated sludge reactors, one VIP (named after Virginia Initiative Plant) biological nutrient removal (BNR) process and one conventional, fully aerobic process, were operated over a range of solids retention times (SRT's) and under the same conditions so that growth yields and specific decay rates could be evaluated and compared. True growth yields (Y's) for the BNR and the conventional processes were equal and were 0.41 gVSS/gCOD. The specific decay rate, b, for the BNR process, 0.063 d, was lower than in the fully aerobic process, 0.110 d-1, indicating that decay occurs at a much lower rate in the anoxic and anaerobic zones of the BNR process.
Effects of an Activated Primary Settling Tank on Biological Phosphorus Removal
Authors: Wedi D.
Published: May 2018

This poster describes results and experiences gained at the wastewater treatment plant of the city of Hirblingen to improve the biological phosphorus removal. Investigations were carried out to study the accumulation of volatile fatty acids in an activated primary settling tank (PST), and in the Extended Anerobic Sludge Contact (EASC) Process. The effluent of the activated primary settling tank provided no higher concentrations of VFA compared with the efffluent of of regular settling tank. Laboratory batch-tests confirmed these results. The elimination of Ntot and Ptot was marginally improved, the gas production in the digester decreased. In batch tests the production of VFA was examined in correlation of organic load, pH value and temperature.
Nitrification–Denitrification of High-Strength Nitrogen Wastes in Two Up-Flow Submerged Filters
Authors: Çeçen F. , Gönenç I. E.
Published: May 2018

Design criteria for nitrification and denitrification of high-strength nitrogenous wastes have been derived by pilot-scale experiments in two submerged filters in series. Molasses proved to be a suitable carbon source in denitrif ication. It has been shown that oxygen is the rate limiting substrate in nitrification and that maximum denitrification rates can only be achieved at an influent COD/NOX−N ratio of approximately 5.
Biochemical Models for Phosphate Accumulating Microorganisms
Authors: del Carmen Doria-Serrano Ma. , González-Martínez S. , Hernández-Esparza M.
Published: May 2018

Although biochemical models for the Pi accumulation of Acinetobacter have been discussed in the literature, attention should be given to the fact that a wastewater treatment plant implies a mixed population of microorganisms and acetate and other low molecular weight fatty acids are not the only nor the most abundant carbon source available. Other microorganisms known to be present in activated sludge plants are able to accumulate polyP, PHB and/or carbohydrates. These bacteria (Pseudomonas, Aeromonas, Moraxella, Klebsiella, and others) may use acetate, but also glucose and other monosaccharides, amino acids, fatty acids and other substances as carbon sources, not only for a fermentation process, but also for the intracellular synthesis of polyP in an aerobic stage, and the release of Pj in the anaerobic one. Though most of the experimental work found in the literature was done using mixed cultures, it is proposed that the main differences in the biochemical models is due to the lack of the definition of the specific substrate transport mechanism across the cellular membrane.
Effect of Delaying the Addition of Polymeric Coagulant-Aid on Settled Water Turbidity
Authors: Brejchova D. , Wiesner M. R.
Published: May 2018

The effect of polymeric coagulant aids and the time of their addition relative to the addition of the primary metal coagulants was investigated in a series of jar tests. Solutions of humic acid were coagulated using iron and aluminum coagulants in conjunction with various commercial polymers. Turbidity, particle size distributions, pH and absorbance of UV light at 254 nm were measured in these experiments. The morphology of flocs was characterized by their fractal dimensions as determined by light scattering as a function of angle. Settled water turbidity appears to be more sensitive to the time of polymer addition when ferric coagulants are used as the primary coagulant in comparison with alum.
Hydrophobic Expanded Vermiculite as a Cleaning Agent for Contaminated Waters
Authors: Martins J. , Fernandes R.
Published: May 2018

Different types of organic and inorganic adsorbents have been used in the treatment of water contaminated by non-polar liquids. This work shows the high efficiency of hydrophobized vermiculite as a cleaning agent for industrial waste waters, as well as for special uses such as adsorption of crude oil from spills in open sea.
Application of Electrodialysis in Purification and Reuse of Spent Alkaline Process Streams
Authors: Xue Z. , Hua Z. , Yao N.
Published: May 2018

Experiments using electrodialysis (ED) units for purification and recovering of spent alkaline process streams, which contain potassium hydroxide, were carried out. According to the experimental results, the spent alkaline process streams, which were produced in production of alkaline storage batteries, can be completely recovered and directly reused as the alkaline process streams. A great number of benefits has been obtained to recover the spent alkaline process streams by using the ED units. The process of the ED unit and the structure of the ED stack are discussed. In this case, optimal current density (170-200 mA/cm2) and current efficiency (75-80%) were observed.
Application of Ultraviolet Radiation for Water Disinfection and Purification in Poland
Authors: Sobotka J.
Published: May 2018

A multi-disciplinary research project on water disinfection using UV radiation was carried out under laboratory conditions as well as in selected pools and waterworks. The influence of UV radiation on physical, chemical and microbiological properties of water was determined. The report describes prototype devices and disinfection systems, as well as methods of determining UV radiation dose and α absorption coefficient.
Use of Biologically Active Barriers for in situ Treatment of Contaminated Groundwater
Authors: Kao C.-M. , Borden R. C.
Published: May 2018

Aerobic biodegradation has been shown to be effective for many fuel spills. However, success is often limited by the inability to provide sufficient oxygen to the contaminated intervals due to the low solubility of oxygen. Nitrate can serve as an electron acceptor in place of oxygen and results in anaerobic biodegradation of organics via denitrification. Since nitrate is less expensive and more soluble than oxygen, it may be more economical to restore fuel-contaminated aquifers using nitrate rather than oxygen. The aim of this study is to design a two layer trench system to offer an alternative of treating groundwater contaminated with low levels of organics which will be less expensive than the biological and physical processes currently in use.

The proposed barrier includes a cement-nutrient(nitrate and phosphate)-briquet layer and a peat layer. Denitrifiers growing on the briquets in the first layer will use the nutrients released from cement-nutrient briquets and degrade BTEX transported into the surface of an attached biofilm. The peat layer will be used to adsorb the residual organics and remove excess nitrate.

Laboratory studies are being conducted to evaluate BTEX biotransformation and assess the potential to remediate contaminated aquifers using a nutrient briquet-peat barrier system. Batch equilibrium experiments were conducted to estimate the nutrient release rate and parameters for transport models. Simulated transport results were then compared with results from a one dimensional column test. Microcosm experiments were performed to evaluate BTEX degradation rate under aerobic, anaerobic, and denitrifying conditions. The microbial transformation of BTEX was also studied in a series of columns: a cement-nutrient briquet column, followed by a peat column and a soil column. This system was used to simulate biodegradation in a saturated-flow barrier. A feed solution containing anoxic synthetic groundwater amended with BTEX was pumped through the column. The column influent and effluent were monitored for dissolved oxygen, BTEX, nitrate, nitrite, ammonia, phosphate, pH, and other relevant parameters.
Bioremediation of PAH-Contaminated Soil via In-Vessel Composting
Authors: Adenuga A. O. , Johnson J. H. , Cannon J. N. , Wan L.
Published: May 2018

This study is being conducted to investigate the biodegradation of polycyclic aromatic hydrocarbons (PAHs) present in contaminated soil using composting technology. Pyrene, a four-ring aromatic hydrocarbon, was chosen as a model PAH compound for the study. Preliminary investigations were carried out to assess the feasibility of soil composting by monitoring (a) carbon to nitrogen (C/N) ratio, (b) microbial consortia diversity, (c) coefficient of permeability and (d) moisture content. The soil was augmented with composted sludge, which was used as a bulking agent and nutrient supplement, in quantities ranging from 0-50% dry weight basis. Tests were conducted in both batch and continuous composters. In the batch composter, forty grams of soil/sludge mixtures in different proportions were spiked with 13.5 mg/kg (dry weight basis) of unlabeled pyrene. The batch composters were aerated and placed in a constant temperature water bath for a period of 21 days. Samples were soxhelet extracted and analyzed on the High Performance Liquid Chromatograph to determine the reduction in pyrene concentration. Analysis of these samples is in progress. In the continuous composter, the soil/sludge mixtures are spiked with both labeled and un-labclcd pyrene to obtain a total radioactivity of 13.5 µci. This process is being monitored for temperature, moisture content, volatile solids and microbial population. Mineralization of pyrene is assessed by quantifying 14CO2 produced.
Enhancing Polynuclear Aromatic Uptake into Bulk Solution with Amphiphilic Colloidal Aggregates
Authors: Edwards D. A. , Liu Z. , Luthy R. G.
Published: May 2018

Aggregated amphiphiles in an aqueous or solid/aqueous system can substantially enhance the uptake of polynuclear aromatic (PNA)compound into a bulk solution. The extent of PNA compound incorporated in an amphiphilic aggregate solution in the absence of solids is linearly dependent on the bulk solution concentration of the aggregated form of the amphiphile. In a system in which solids are in contact with a solution, however, the relationship is nonlinear as a result of the adherence of both amphiphile and PNA compound to the solids. The formation of amphiphile aggregates in the bulk solution of a system containing solids occurs only after a much greater amount of amphiphile has been added to the system than would be required for a similar system containing only solution. The partitioning of PNA compound between the solid, the colloidal amphiphilic aggregates in bulk solution, and the rest of the bulk solution can be characterized with two different partition coefficients and a number of other parameters, all of which are obtainable from independent experiments. The total fraction of PNA compound incorporated into bulk solution can be estimated with a mathematical model. Model results for the uptake of pyrene into a C8PE9.5 aggregate solution are shown plotted with experimental data. The effect of amphiphile aggregates on PNA compound transport in porous media may in some cases be substantial.
Chronic Toxicity of a Fluoride Mixture to Freshwater Organisms
Authors: Khan A. , Kent D. , Barbieri J. , Khan S.
Published: May 2018

Chronic toxicity of a solution, containing 1.5% of Hydrofluozirconic acid and 1.0% of Ammonium bifluoride as the active ingredients, to two freshwater species was investigated in this study. The fathead minnow, Pimephalespromelas, and the water flea, Ceriodaphniadubia, were used as test organisms. Survival, growth and/or reproduction were used as endpoints. The solution had a low pH of 2.5 and was highly toxic to both species. Following 7 days of exposure of fathead fry to the solution, a 7 day LC50 of 2.26% was obtained. A survival NOEC of 1.25% solution and a growth NOEC of 0.625% was obtained. Survival data from the ceriodaphnia toxicity test produced an 8 day LC50 of 3.11%. A survival NOEC of 2.5% and a reproduction NOEC of 0.625% was also determined. Fathead minnow fry were tested again for chronic toxicity after adjusting the pH of the solution from 2.5 to 7.5. The pH adjusted solution yielded a 7 day LC50 of less than 6.25%, the lowest concentration tested. Both survival and growth had a NOEC of less than 6.25%.
Nitrification Treatability of Whole Microorganisms Immobilized by the PVA-Freezing Method
Authors: Asano H. , Myoga H. , Asano M. , Toyao M.
Published: May 2018

We used whole microorganisms immobilized by the PVA-freezing method (in order to prevent microorganism wash-out) to investigate the efficiency of nitrification. In general, denitrified or oxidized effluents are recycled to the nitrification tank to provide alkalinity control in biological nitrogen removal systems. We found that allowable volumetric loading during nitrification was different for the recycling and once-through operations, using a biofilm nitrogen removal system in a fixed bed. Then, the nitrification efficiency of a recycling operation in a biological nitrogen removal system was compared with that of a once-through operation, using immobilized microorganisms. The results showed that the ratio of allowable volumetric loading in the recycling operation was 60% of that in the once-through operation.
Experimental Studies on Advanced Treatment of Wastewater for Amenity Use
Authors: Kuribayashi S.
Published: May 2018

At Kawasaki City, the “Kawasaki Aqua-promenade Project” is being set up for amenity use of treated sewage in artificial “Seseragi” streams. From fiscal year 1987, an experimental study has been done in order to determine the advanced treatment process to be introduced in the Todoroki Sewage Works (planned water flow 395, 500 m3/d by pure oxygen activated sludge process) required for the implementation of the above project. In this study, a pilot scale experimental system was used on various advanced treatment processes required to achieve the water quality standards for amenity use (for their performance comparison). The results obtained indicate that the biological aerated filter (BAF) combined with ozonation is the optimum process to be introduced to achieve the water quality standards effectively and economically.
Relationship for Clarification Efficiency of Circular Secondary Clarifiers
Authors: Voutchkov N. S.
Published: May 2018

This paper discusses a regression-based model describing clarification efficiency of circular activated sludge secondary clarifiers. Surface overflow rate was found to be well correlated with effluent suspended solids, sidewater depth and settled sludge volume at three full scale wastewater treatment plants during a six month study. Relationship was verified to be sufficiently accurate for prediction of effluent suspended solids concentration over a six month period at another three treatment plants.
Eutrophication Studies on Tolo Harbour, Hong Kong
Authors: Sin Y. S. , Chau K. W.
Published: May 2018

Tolo Harbour is an almost land-locked waterbody with only one narrow marine inlet to the open sea at Mirs Bay in the Eastern Waters of Hong Kong. Due to its enclosed nature, the waste assimilative capacity is very limited. Besides, it receives substantial pollutant loads from the two sewage treatment plants in the Tolo catchment, livestock rearing industry and other industrial discharges. The building-up of the organic matter and nutrients in the Harbour has caused an increasing occurence of red tides in the past decade. This paper describes the trophic status of the Tolo Harbour based on the monitoring stations results obtained from the Hong Kong Government with particular reference to the chlorophyll-a, secchi depth, total nitrogen (TN) and total phosphorus (TP) concentration.
Correlation of Water Quality Parameters in Tolo Harbour, Hong Kong
Authors: Chau K. W. , Sin Y. S.
Published: May 2018

In this paper, long-term biweekly measurements on the various water quality parameters in Tolo Harbour from year 1982 to 1990, subsequent to the declaration of the area as water control zone, were analyzed and correlated. Correlations have been demonstrated between surface chlorophyll-a concentration with secchi depth and with total nitrogen concentration (TN) in the three sub-zones of Tolo Harbour in Hong Kong with different water quality objectives. The correlation between chlorophyll-a concentration and total phosphorus concentration (TP) is less significant which can be explained by the TN/TP ratio. The correlations are useful for water management, planning and effective pollution control on the land-locked estuary.
Water Reclamation of the Po River in the Turin Area
Authors: Romano P. , Ranzani R. , Tecchiati F.
Published: May 2018

The effects of the decade long (1980-1990) reclamation process carried out on the Po River water (Italy's most important river) in Turin's metropolitan area are evaluated. Water quality is assessed by analyzing the biological data obtained through the application of the E.B.I, index. The latest data (January 1991) demonstrate that the negative impact of an area numbering some 3 million equivalent inhabitants can be minimized.
Watermolds and Their Activity in Kumaun Himalaya, India
Authors: Khulbe R. D.
Published: May 2018

Five important lakes of Kumaun Himalaya were studied for the occurrence of watermolds and their parasitic association with eggs, fry and adults of fishes. A total of 22 watermolds were found to be distributed in different lakes. Of them, 14 species caused infection in fishes. The facultative watermolds caused various abnormalities in fishes including mass mortality under natural conditions. Saprolegniaparasitica showed maximum infection in fishes. Adults of Puntiusconchonius, P. ticto, Torputitora and T. tor showed maximum fungal infection.
Strategies for Dealing with the Effects of Increasing Urbanisation on Surface Water Quality
Authors: Lötter L. H.
Published: May 2018

Extensive research into sewage purification processes has enabled Johannesburg to produce environmentally high quality effluent from wastewater treatment plants, thus successfully controlling the largest point source contribution to surface water pollution in the Johannesburg metropolitan area. However, a variety of other point and diffuse sources require attention in order to protect the country's single most important resource.

Case studies involving pollution from sanitary sewers, zoological gardens, informal settlements and mine dumps are discussed. The effect of more stringent effluent control on the quality of rivers receiving sewage effluent is also discussed.
A Comparative Study of Full-Scale Sludge Dewatering Equipment
Authors: Andreasen Ina , Nielsen Bente
Published: May 2018

A comparative study of 4 different types of full-scale sludge dewatering units was performed in 1990 by I. Krüger AS in co-operation with the equipment suppliers.

The purpose of the study was to examine the capability of the dewatering equipment on the “new” sludge types from wastewater treatment plants with N and P removal.

The achieved results have formed the basis of a financial evaluation comprising construction and operating costs. The objective of the evaluation is to compare the total costs involved in sludge dewatering and disposal.

The relatively cheap types of dewatering units (belt filter press, solid bowl centrifuge) produce dewatered sludge with a lower dry solids content than the more expensive equipment (press centrifuge, membrane filter press).

The latter types should consequently primarily be applied where the dewatered sludge has to meet special requirements and in situations in which disposal costs are very high.
Studies on Wastewater Treatment by Means of Integrated Biological Pond System: Design and Function of Macrophytes
Authors: Zhenbin Wu , Yicheng Xia , Jiaqi Deng , Qijun Kuang , Facui Zhan , Xitao Chen
Published: May 2018

A biological treatment pond system to purify municipal wastewater from a medium-sized city has been operated for 3 years and gained good results, Macrophytes took a very important part in this system. The macrophyte ponds and zones were designed spacially and periodically different to test their purification efficiencies. The purifing system was divided into three functional zones: purifing zone, effluent upgrading zone and multi-utilization zone. Macrophytes were planted in several subzones in series in some ponds. The experiments showed that the multi-macrophyte zone system revealed greater purification efficiencies than those of traditional oxidation ponds as well as general macrophyte ponds. The system reached high reductions of COD, BOD, TSS, TN and TP.The activity of mutagenic agents and numbers of virus and bacteria were significantly decreased during the process of purification. The effluent fron the system was greatly upgraded and could be used in fishery and agriculture. The harvested macrophytes from the purifing zone and effluent upgrading zone could be put into the multi-utilization zone as feed, fertilizer, biogas, etc. The idea of resourcization of wastewater was being put into practice. The studies also showed that some macrophytes revealed strong ability to inhibit algae growth not because of light, nutrient and space competition. These results had been used in the treatment system design and gained expected effeets. Plant harvesting did not yield dramatic effects on reductions of the main pollutants, though it did affect remarkably the biomass productivity of the macrophytes.
Electrokinetics in Clays and Filter Cakes of Activated Sludge
Authors: Laursen S.
Published: May 2018

The electroosmotic coefficient, L12, was measured for a series of bentonite specimens with different water and salt content, the salts being CaCl2, BaCl2 and MgCl2. A simple relation between the electric conductivity of the clay, κ*, and the electric conductivity of the solution in equilibrium with the clay, κ, was obtained. It is not, however, a linear relation as e.g. an Archie law dependance. When the conductivity of the equilibrium solution is less than 0.4 S/m the clay conductivity exceeds the solution conductivity. The electroosmotic coefficient of the clay specimens is found to be similar in magnitude to that of filter cakes of activated sludge. Data from literature shows that in general materials with large pores (1 µm) have lower L12 and κ* than materials with small pores. The sludge filter cakes are thus found to resemble clay and polymer membranes rather than particle plugs.
Characterization and Dewatering of Activated Sludge from the Pulp and Paper Industry
Authors: Pere J. , Alen R. , Viikari L. , Eriksson L.
Published: May 2018

Floc properties and dewatering of activated sludge from the pulp and paper industry were studied prior to and after an oxidative conditioning using Fenton's reagent Sludge samples were taken from four treatment plants, which differed with respect to organic loadings and wastewater source. Poor dewaterability was typical of heavily loaded sludges and a positive correlation between filtrability and the concentration of exopolysaccharides was observed. Oxidative conditioning improved the dewaterability of all the sludges tested, but especially that of heavily loaded sludges. Lab-scale piston press results were also comparable with those of controls conditioned with polyelectrolytes. As a result of the conditioning, the surface charge density of the flocs decreased and the contact angles of filter cakes were increased, which enhanced flocculation and settleability. It is possible that hydroxyl groups are oxidized during the oxidative treatment to carboxyl groups, which are more hydrophobic at low pH. This hypothesis was partly supported by FTIR-analysis, but obviously other mechanisms were also involved.
Chemical Pretreatment of Dairy Wastewater
Authors: Rusten Bjørn , Lundar Arne , Eide Ola , Ødegaard Hallvard
Published: May 2018

Chemical treatment of dairy wastewater was studied, using dissolved air flotation for solids separation. Four different combinations of coagulants were tested. Total COD removal was very dependent on the influent CODF/CODT ratio, with the bigbest removal efficiencies at the lowest CODF/CODT ratios. About 60% removal of total COD could be achieved at a CODF/CODT ratio of 0.6. JKL (FeClSO4) removed 2-3% more COD than H2SO4 plus CMC (carboxy methyl cellulose), and 4-6% more COD than lactic acid plus CMC. H2SO4 plus LSA (lignosulphonic acid) bad the poorest removal efficiencies. Use of lactic acid plus CMC is a novel and promising approach. Further studies of the lactic acid plus CMC process is recommended, especially with regard to the feed value of the sludge.
Hybrid Upflow Anaerobic Sludge Blanket Reactor (HUASBR) Treatment of Dairy Effluents
Authors: Öztürk I. , Eroglu V. , Ubay G. , Demir I.
Published: May 2018

This paper covers the treatability results of a laboratory-scale hybrid upflow anaerobic sludge blanket reactor (HUASBR) treating dairy effluents from a large integrated industry with a maximum production capacity of 500 tons of milk per day. The study began wilb the determination of effluent characteristics and pollution profile for the investigated dairy industry. As a result of observations, by-product recovery and waste reduction alternatives were investigated by in-plant control measures. Anaerobic treatability studies were conducted by a laboratory-scale hybrid upflow anaerobic reactor with an effective volume of 81.

The reactor was operated more that 270 days under mesophilic conditions and it was fed wilb the combined effluents from the investigated dairy industry. The hydraulic retention times ranged from 0.21 to 0.96 days under normal operating conditions after the start up. COD removal efficiencies of more than 87% were achieved at an organic loading rate (OLR) of 8.5 kg COD/m3·d OLR was gradually increased from 2.54 to 7.1 kg COD/m3·d within 15 days but the anaerobic reactor performances did not change significantly. The reactor was operated under varying feed characteristics to test the response of the system to high strength acid whey. The system can tolerate OLRs as high as 17 kg COD/m3·d with an average COD removal efficiency of 75% for two weeks. Although the reactor was fed by diluted effluent with an average COD of 1070 mg/l at very high hydraulic loadings (HRT=5 hours), 75% removals of COD were achieved under these conditions.
Computer and Experimental Simulations of the Production of Methane Gas from Municipal Solid Waste
Authors: Lee J. J. , Jung I. H. , Lee W. B. , Kim J.-O.
Published: May 2018

Prediction of quantity and quality of gas produced after landfilling is not easy because it is strongly dependent on the hydrological and biological parameters. The objective of this study was to develop the LEAGA-I model by combining a hydrological module of unsaturated flow theory with a biological decomposition module in order to predict methane gas production, even carbon dioxide gas production, using a pilot scale lysimeter. For a biological module, especially, three-step procedures, i.e., hydrolysis of refuse, acid formation, and methane formation were applied. As a result of this study, the LEAGA-1 model, developed by combining a hydrological module with a biological module, not only provided more reasonable prediction of gas production during landfill stabilization, but also turned out to be a useful model, as a result of comparison of the simulated values with the observed values of lab-reactor.
Investigation of the Development of Biological and Chemical Conditions in the VíR Reservoir 30 Years after Impoundment
Authors: Žáková Z. , Beránková D. , Kocková E. , Križ P. , Mlejnková H.
Published: May 2018

Water quality in the Vír Reservoir (the main water source in the Svratka watershed) and its tributaries was investigated in terms of the physico-chemical, biological and microbiological characteristics during 1988-1990. The results of investigation showed that the Vír Reservoir in spite of its great depth (more than 60 m) and favourable morphology 30 years after impoundment has become more eutrophic. Long-term changes were characterized by log normal function which demonstrated the increase of the nitrate concentration from the level 5-10 mg.l−1 at the beginning of this period to the present concentrations, which are more than 20 mg.l−1 in the raw water to the drinking water treatment plant and also in the inflow water (the Svratka River in Dalečín). In a similar way there was an increase in average concentrations of PO43−. The main indicators of the accelerated eutrophication of the Vír reservoir are the occurrence of water blooms of blue-green algae, the summer oxygen depletion and increased concentrations of Fe and Mn in the hypolimnion, while pH and dissolved oxygen increased in the epilimnion. The relationship between concentrations of nitrates and application rates of mineral nitrogen fertilizers in the watershed was highly significant. From this evaluation we drew the conclusion that the main cause of eutrophication is the increased input of nutrients from the watershed.
Relative Importance of Internal Sources of Phosphorus and Organic Matter in Northern Finnish Reservoirs
Authors: Hellsten S. K. , Virtanen M. O. , Nenonen O. S. , Kinnunen K. A. , Riihimäki J. M.
Published: May 2018

Two large reservoirs Lokka (417 km2) and Porttipahta (214 km2) were built at the upper part of river Kemijoki watercourse in northern Finland in the early 1970s. Both reservoirs were built to produce hydropower with wide water level regulation range (Lokka max. 5 m, Porttipahta max. 11 m). Flooded area consisted mainly of peatlands and forests. Water level is lowered during winter, when reservoirs are covered by ice and the energy need is greatest. Regulation was extensive during the first decade and water quality problems occurred. Wintertime oxygen concentration was very low and amount of phosphorus was high. This situation was caused by degradation of organic matter released from bottom. Organic matter was mainly released from peatlands pressured by penetrating ice and by breakdown of peat during the summer. Amount of total phosphorus is quite high compared to natural lakes. Main sources of loading during the first years of the reservoirs were at the littoral zone, where waves and currents caused erosion. The importance of the pelagic zone becomes more obvious as reservoirs age; bottom area is covered by thick layer of sediment consisting mainly of eroded peat. The bottom sediment forms a store of organic matter and phosphorus, which can be released during winter, when oxygen concentration is very low and also other transport mechanisms (convection, diffusion) exist. Nowadays, when the regulation amplitude is only 2-3 m/yr, water quality is more stable. In that situation the wind-caused resuspension of sediment can be quite important as a transport mechanism of organic matter and nutrients in shallow and open reservoirs.
Entrapment of Mixed Microbial Cells for Water and Wastewater Treatment
Authors: Yang P. Y. , Nitisoravut S. , See T. S.
Published: May 2018

An entrapment of mixed microbial cells process was used to remove the pesticide Ethylene Dibromide (EDB), Trichlopropane (TCP) and nitrate contaminated in the groundwater. The mixed microbes were entrapped into a polymeric cellulose triacetate. The system is able to remove (aerobically) more than 90% of EDB (influent concentration of 300 μg/l) at more than 30 minutes of hydraulic retention time (HRT). TCP (influent concentration of 2.81 μg/l) could not be detected in the effluent at the same HRT. The system is also able to remove (anaerobically) more than 99% of nitrate influent concentration of NO3-N ranging from 50 to 850 mg/l) at an HRT of more than 2 hours. The system has shown very promising results in respect of the removal of trace pesticide and nitrate contaminated groundwater. It can also be considered as an alternative for direct treatment of nitrate-rich water or in a combination with an ion exchange process with an intermittent to eliminate the high nitrate concentration from the spent regenerant. The system could easily develop a package plant for removal of trace organics and inorganics from the groundwater.
Study on Mechanism of Anaerobic Sludge Granulation in UASB Reactors
Authors: Jian Chen , Shi-yi Lun
Published: May 2018

Sludge granulation in a 15 m3 UASB reactor, with alcoholic stillage from ethanol fermentation broth as influent, has been studied. Based on kinetic data as well as both scanning and transmitting scope observation and identification, a hypothesis for the mechanism of anaerobic sludge granulation is suggested. The first step of granulation is the formation of nuclei. The bacteria involved in the nucleus formation are mainly M. sarcina and M. thrix. The acetic acid concentration and the “selection pressure” play a decisive role for determining the nucleus formation. A wide spectrum of other bacteria, which the methanogens must syntrophically grow with, also play a very important role during the second step, that is the process of a nucleus growing into a granule.
Greenhouse Gas – N2O Production during Denitrification in Wastewater Treatment
Authors: Hong Zheng , Hanaki Keisuke , Matsuo Tomonori
Published: May 2018

Laboratory scale experiments were carried out in order to examine the N2O production during denitrification. The results show that a lower COD/N03-N ratio and shorter HRT caused higher N2O production.
Studies on the Purification and Reclaimation of Wastewater from a Medium-Sized City by an Integrated Biological Pond System
Authors: Zhen-bin Wu , Yi-cheng Xia , Yong-yuan Zhang , Jia-qi Deng , Xi-tao Chen , Fa-cui Zhan , De-ming Wang
Published: May 2018

The feasibility of an inexpensive wastewater treatment system is evaluated in this study. An integrated biological pond system was operated for more than 3 years to purify the wastewater from a medium-sized city, Central China. The experiment was conducted in 3 phases with different treatment combinations for testing their purification efficiencies. The pond system was divided into 3 functional regions: influent purification, effluent upgrading and multi-utilization. These regions were further divided into several zones and subzones. Various kinds of aquatic organisms, including macrophytes, algae, microorganisms and zooplankton, were effectively cooperating in the wastewater treatment in this system. The system attained high reductions of BOD5, COD, TSS, TN, TP and other pollutants. The purification efficiencies of this system were higher than those of most traditional oxidation ponds or ordinary macrophyte ponds. The mutagenic effect and numbers of bacteria and viruses declined significantly during the process of purification. After the wastewater flowed through the upgrading zone, the concentrations of pollutants and algae evidently decreased. Plant harvesting did not yield dramatic effects on reductions of the main pollutants, though it did significantly affect the biomass productivity of the macrophytes. The effluent from this system could be utilized in irrigation and aquaculture. Some aquatic products were harvested from this system and some biomass was utilized for food, fertilizer, fodder and some other uses. The wastewater was reclaimed for various purposes.
Planning Replicable Small Flow Wastewater Treatment Facilities in Developing Nations
Authors: Gaber A. , Antill M. , Kimball W. , Abdel Wahab R.
Published: May 2018

The implementation of urban village wastewater treatment plants in developing countries has historically been primarily a function of appropriate technology choice and deciding which of the many needy communities should receive the available funding and priority attention. Usually this process is driven by an outside funding agency who views the planning, design, and construction steps as relatively insignificant milestones in the overall effort required to quickly better a community's sanitary drainage problems. With the exception of very small scale type sanitation projects which have relatively simple replication steps, the development emphasis tends to be on the final treatment plant product with little or no attention specifically focused on community participation and institutionalizing national and local policies and procedures needed for future locally sponsored facilities replication. In contrast to this, the Government of Egypt (GOE) enacted a fresh approach through a Local Development Program with the United States AID program. An overview is presented of the guiding principals of the program which produced the first 24 working wastewater systems including gravity sewers, sewage pumping stations and wastewater treatment plants which were designed and constructed by local entities in Egypt. The wastewater projects cover five different treatment technologies implemented in both delta and desert regions.
The Option of Appropriate System for Wastewater Treatment in Low-Density Areas
Authors: Ukita Masao , Shirota Hisatake , Nakanishi Hiroshi
Published: May 2018

The method for selecting the appropriate treatment system in low-density areas was studied by statistical data analyses and questionnaire surveys. The main results obtained are as follows.(l) The efficiency of sewerage service has been decreasing. With decrease of the population density in served areas, treatment cost is increasing from 7,000 yen/household in 1961 to near 40,000 in 1989.(2) By considering the external cost of treated water quality, the marginal house density beyond which collective systems become advantageous, was estimated to be 9.5 houses/ha compared to the original value of 13 houses/ha.(3) Improvement of water quality, saving energy, and efficient uses of sludge are considered to be important for the environmental impact of sewerage systems. Suitable allocation of optional treatment systems, energy saving technology and prevention of sludge contamination must be the important issues for the sewerage service on a small scale.
The Effects of Fill Strategies on SBR Performance under Nitrogen Deficiency and Rich Conditions
Authors: Sheker R. E. , Aris R. M. , Shieh W. K.
Published: May 2018

The effects of anoxic and oxic fill strategies on SBR performance under nitrogen (NH4Cl as the nitrogen source) deficiency and rich conditions are evaluated using glucose as the sole substrate. The performance is evaluated according to substrate removal, sludge settleability, supernatant suspended solids (SS), and reactor biomass concentration. Substrate removal efficiencies are found to be independent of the fill strategies adopted under all conditions tested. The incorporation of anoxic selector environment fails to prevent the development of bulking sludge under nitrogen deficiency conditions thereby resulting in a gradual depletion of reactor biomass. Under nitrogen rich conditions, on the other hand, the sludge settleability improves significantly by adopting the anoxic fill strategy. Furthermore, SS readings taken at the end of settling period are greater with anoxic fill than with oxic fill, indicating that the latter discourages the growth of dispersed bacteria.