The physicochemical speciation of Cd, Pb, Cu, Fe and Mn in the final effluent of a sewage treatment works and its impact on speciation in the receiving river

A scheme for the speciation of metals in freshwaters has been applied to the analysis of the final effluent from a sewage treatment plant and to the receiving river upstream and downstream of the effluent outfall. The treatment plant was selected because of the high influent and effluent concentrations of Cd. The metal speciation patterns in the effluent are interpreted primarily in terms of organic interactions, which appear to be exerting a solubilizing effect on Cd and Cu, but not on the Pb and Fe which are principally associated with the particulate size fraction (> 12 μm). The influx of metals with the sewage effluent alters the speciation pattern in the river. A large part of the Cd is added to the smallest size fraction (< 0.015 μm). However, the major part of each metal, with the exception of Mn, is associated with the colloidal and particulate size fractions, thus minimising the immediate toxic significance to aquatic life.     

从化学成分探讨三种固废物掺入页岩烧结砖可行性

传统的粘土材料具有生产能耗高、破坏耕地及自重较大等缺点,所以,国家提倡发展新型墙体材料。通过分析及对比淤泥、污泥和秸秆三种固体废弃物与页岩的化学成分,得出淤泥可替代部分页岩在制砖原料中大量掺入,污泥和秸秆可作为制砖造孔剂少量掺入。     

Removal of indigenous rotaviruses during primary settling and activated-sludge treatment of raw sewage

An eight month study of indigenous rotavirus removal during primary settling and activated sludge treatment of raw sewage was made in a plant in Houston, Texas treating 1.5 million gal day⁻¹. An average reduction of 44–55% was obtained by primary settling and a 93–99% reduction was achieved in final chlorinated effluents. Composite sampling at 1 h intervals over a 24 h period indicated average removals of 85% compared to a misleading 6% indicated by one set of grab samples of raw sewage and effluent collected simultaneously. Quantification of rotaviruses was made by immunofluorescent foci counts 24 h after addition of sample concentrates to coverslip cultures of fetal rhesus kidney cells. Rotaviruses varied from 40–5101⁻¹ of raw sewage and from 0 to 25 in the final chlorinated effluent.     

Centrifugal fractionation studies on the particulates of palm oil mill effluent

Separation of palm oil mill effluent into various particulate fractions from the soluble constituents was achieved by high-speed centrifugation. The particulates were found to account for only 1.7–2.6% (w/w) of the effluent. These particulates were shown to be the colloidal rod-like particles of macrofibrils, raphide particles and plant cell debris, the last being the major component. Together they contributed slightly less than 50% to the pollutant level of the effluent. Anaerobic digestion of the palm oil mill effluent resulted in a 96% reduction in BOD and 87% reduction in suspended solids. The plant cell debris was completely removed whereas the raphide particles seemed intact after the anaerobic treatment. The anaerobic process also caused a decrease in particle size and number of the colloidal macrofibrils.     

Denitrification at various carbon to nitrogen ratios

The aim of this research was to examine whether the residual dissolved organic matter, remaining in chemically treated raw sewage would be able to satisfy the carbon demand in a denitrification process. In the first stage of research we investigated the effect of type and amount of organic substrate on denitrification efficiency. The critical weight ratios of methanol and sodium acetate to total concentration of nitrite and nitrate which enable the occurrence of complete denitrification were studied. It was found that when the concentration of the organic matter was expressed as BOD, a critical ratio of (mg BOD/mgΣNO_x-N) = 2.3 ensured 100% denitrification. Lower ratios decreased denitrification efficiencies proportionally. The same critical ratio was found when the chemically treated raw sewage was used as an available organic carbon source. Denitrification-nitrification process was also investigated by recirculating the nitrified effluent into the denitrification reactor, to which effluents from chemical treatment of raw sewage were fed to satisfy the carbon demand. The same critical ratio of BOD/ΣNO_x-N) = 2.3 was found. By increasing the recycling, nitrate concentration in effluent was decreased.     

The ecology of "fecal indicator" bacteria commonly found in pulp and paper mill water systems

Coliform bacteria have long been used to indicate fecal contamination of water and thus a health hazard. In this study, the in-mill water and external effluent treatment systems of seven typical Canadian pulp and paper mills were all shown to support the growth of numerous coliforms, especially Klebsiella Spp., Escherichia coli. Enterobacter spp., and Citrobacter spp. In all mills and most sampled locations, klebsiellas were the predominant coliforms. Although all but one of the mills had no sewage input and most disinfected their feed (input) water, all contained the most typical fecal indicator bacterium, E. coli. Many of the mill coliforms were classified as fecal coliforms by standard "MPN" and metabolic tests, but this was shown to be due to their thermotolerance, not their origin. Mill coliforms were shown not to be just simple transients from feedwater or furnish (wood), but to be continuously growing, especially in some of the primary clarifiers. Isolated mill coliforms grew very well on a sterilized raw combined mill effluent. The fecal streptococci (enterococci), alternative indicators of fecal health hazards, were common in all mills in the absence of sewage. Ten strains of E. coli isolated from four mills were all shown to be non-toxigenic strains of harmless serotypes. No salmonellas were found. Therefore, the use of total coliform, fecal coliform, enterococci, or E. coli counts as indicators of fecal contamination, and thus of health hazard in pulp and paper mill effluents or biosolids (sludges) known to be free of fecal input is invalid.     

Oestrogens and oestrogenic activity in raw and treated water in Severn Trent Water

Sewage effluent discharged to surface water has been shown to contain human hormones, particularly oestrogens, and synthetic chemicals which may be able to disrupt the endocrine system. Since many surface waters which receive sewage effluent are subsequently used as drinking water sources, it is important to demonstrate that treated drinking water is not contaminated. Oestrogenic activity in rivers and drinking water in the region of Severn Trent Water was studied using a combination of bioassay, to integrate exposure over time, and advanced chemical analysis. There was little or no evidence of substances that were oestrogenic, even in waters receiving significant amounts of sewage effluent. Oestrogenic activity, as measured in the rainbow trout vitellogenin assay, was seen at the Tame/Trent confluence but this activity was relatively weak. There was no activity detected at raw water intakes and no hormones or substances that are oestrogenic were detected in the final drinking water.     

Volatile organic acids in raw wastewater and in physico-chemical treatment

The purpose of the present study was to identify soluble organics, which comprise the high BOD remaining in the effluent from direct physico-chemical treatment of strong raw sewage. Salts of volatile organic acids were found to be the main constituents of the organic fraction remaining after chemical treatment and activated carbon adsorption. The fate of the volatile acids such as acetic, propionic, butyric, valeric, isovaleric and hexanoic acids was followed in each stage of the physicochemical treatment.     

An investigation into the occurrence of sewage fungus in rivers containing papermill effluents—II. Chemical analysis of mill effluents

This is the second in a series of four articles describing research undertaken at PIRA during 1978–1980 on the causes and prevention of sewage fungus growth in rivers receiving paper and board mill effluents. This paper describes the sampling and analytical programme at three U.K. paper and board mills, the objective of which was to characterise the dissolved organic matter in final effluents and component wastewater streams. The analyses conducted were dissolved organic carbon (DOC), carbohydrate, glucose, gelatin, melamine, hydrolysed sugars and molecular weight distribution. The results are related to the raw materials and manufacturing processes used at each mill site.     

The growth of cladophora glomerata in a river receiving sewage effluent

A considerable improvement in the natural flora of the River Great Stour has occurred since the mid-1960s when dense growths of Cladophora glomerata dominated sections of the river with the disappearance of some rooted macrophytes. Cladophora growths in the river in response to changing river conditions and sewage treatment operations during a thirty year period are reviewed. A vegetation mapping programme undertaken from 1978 to 1982 to assess the influence of a sewage treatment works discharge on the growth of the filamentous alga has shown that previous recommendations to reduce dissolved phosphorus concentrations in the final effluent need not be implemented.     

Mineral flotation—a study of the re-use and disposal of aqueous solutions containing organic reagents

The fate of organic reagents added to a froth flotation process for the concentration of fluorite, barite and lead has been studied as an example of a unit process employing water as a transport medium. It has been shown that approximately half of the organic material added to the circuit was discarded in the mill tailings water—the other half being lost from solution within the circuit. Estimates have been made of the amounts removed in the different unit operations and of the amounts discarded in the final effluents from the tailings disposal system. The effluent from the operation studied has been shown to have a barely detectable effect on the organic levels in the river system into which it was discharged.BOD₅ and BOD₁₀ measurements have been made on fifteen of the commonest organic reagents used in the froth flotation process. A wide range of degradation behaviour is revealed.A survey has been made of the methods that have been adopted and proposed for the removal of residual organic reagents from froth flotation process waters and of the production of consistent supplies of water for re-use.     

Microbiological effects of wastewater effluent discharge into coastal waters of Puerto Rico

Microbiological effects of non-disinfected, combined chemical and domestic wastewater effluent discharge into coastal waters north of Barceloneta. Puerto Rico were investigated by membrane filter enumeration of fecal indicator bacteria and by enrichment isolation of specific pathogens. A wastewater plume was detected and delineated around the sewage outfall, located 800 m offshore and 30 m below the ocean surface. Fecal coliform and fecal streptococcus counts within the plume were significantly (F test) larger than comparable counts outside the plume. The shape and location of the plume was compatible with current patterns and prevailing winds and extended as far as 3.7 km west of the outfall, at which point the fecal coliform count was 146 100 ml⁻¹. The average non-plume fecal coliform concentration was 6.7 100 ml⁻¹. Specific pathogens isolated included Salmonella and Vibrio spp, including V. cholerae non-01 serovar isolated from a nearby river also impacted by the sewage plant.     

Behaviour in a river and dam of coliform bacteria with transferable or non-transferable drug resistance

The water in a river and the dam into which it flows was assayed for total coliforms and coliforms with transferable (R⁺) or non-transferable (R^-) resistance to five antimicrobial drugs. The effluent of a sewage works is discharged into the river 10 km upstream of the dam. The ratio of resistant to total coliforms decreased between the sewage works and the dam, but increased between the influent and effluent of the dam. This ratio was higher in the dam effluent than in the river upstream of the sewage works. No difference was detected in the survival of drug-sensitive and known R⁺ and R^- strains in distilled water or saline, or in dialysis bags immersed in the river or dam. Selection of those R⁺ strains resistant to a wide spectrum of drugs occurred in the river and dam. Immersed dialysis bags containing donor and recipient strains were used to demonstrate R factor transfer in the waters concerned. Three out of ten R⁺ strains isolated from the effluent of the dam yielded positive results. These donors were resistant to a wide spectrum of drugs but all determinants were transmitted at a relatively low frequency in the water. One donor had a higher frequency of transfer at 20 than at 37°C. The water pollution significance of these findings is discussed.     

Domestic and agricultural contributions to the inputs of phosphorus and nitrogen to Lough Neagh

Loadings of nitrogen and phosphorus from the major river catchments that contribute to Lough Neagh have been measured for the years 1971–1974. Analysis of this data indicated that there was a very significant correlation between soluble ortho-P loadings and the human but not the animal population densities of the catchments. The land drainage and agricultural contribution of soluble ortho-P to Lough Neagh was 0.14 kg P-ha⁻¹·yr⁻¹ which was about 25% of the measured soluble ortho-P loading to the Lough. It was estimated that the introduction of phosphorus removal treatment at sewage works connected to populations greater than 2000 could curtail 50% of the phosphorus available to support algal growth in the Lough. There was a good correlation between nitrogen fertilisers usage in Northern Ireland and the nitrate concentration in the major rivers.     

Responses of the three test algae of the algal assay procedure: Bottle test

The Algal Assay Procedure (AAP): Bottle Test utilizes three test organisms which, under standardized culture conditions, give a range of responses to the physical and nutritional states of test waters. The test algae of the AAP are Selenastrum capricornutum, Microcystis aeruginosa and Anabaena flos-aquae. The responses of these organisms to light intensities and to micro- and macronutrients are described. Phosphate spikes as low as 1–2 μg P l⁻¹ are shown to give a measurable bioassay response in highly oligotrophic waters.The AAP test algae are used to assess the effects of nutrient enrichment with sewage in waters from a cross-section of U.S. lakes. Enrichment of oligotrophic waters with primary or secondary sewage effluent results in significant growth of the three algae, while sewage additions to eutrophic waters cause little or no significant increase in algal growth rate or maximum standing crop. The response of the AAP algae also indicate that nutrient removal by tertiary treatment greatly reduces the stimulatory properties of sewage. In the presence of tertiary sewage, growth rate and maximum standing crop of the three test organisms are near those of lake water controls.The AAP test protocol is shown to be useful in the determination of limiting nutrients and in the comparison of the algal growth potential of natural waters to that of defined media.     

Sources of water to the seawater well which supplies the fish ponds in Eilat Implications for fishpond management

The sources of water to the well supplying the fishponds in Eilat were determined using a simple mass balance approach, in which the concentration of various components in the source waters were measured and a series of simultaneous equations solved to determine the hydrological budget. It was calculated that 80% of the water supplied to the well was recycled pond water, 10% was seawater and 10% was sewage effluent. On the basis of major ion determinations, it was shown that there could be no significant contribution from natural groundwater.This method of water supply has both disadvantages and benefits. The fishpond system was operated to produce gilthead seabream and grey mullet in the pond and oysters on the pond effluent. The major disadvantage was that the excess nutrients supplied in the inflow may have limited the total biomass of fish which could be grown in the ponds by making them more susceptible to mass mortalities due to both high oxygen or high ammonia/low oxygen concentrations.The benefits include the high productivity of diatoms due to the nutrients supplied which enabled there to be a successful oyster culture. In addition, 95–97% of the nitrogen supplied in the sources was as ammonium which is toxic to fish. After passage through the aerobic groundwater, 97% of the dissolved nitrogen was in the form of nitrate. At the same time, the coliform counts were reduced to undetectable levels. The major ion composition of the pond was enriched 25% relative to seawater because the evaporated seawater was replaced by sewage effluent. Despite this unusual ionic composition fish, oysters and prawns were grown successfully in these ponds.     

Phosphorus concentrations in the River Dun, the Kennet and Avon Canal and the River Kennet, southern England

Variations in phosphorus (P) concentrations in an agriculturally impacted river draining a Chalk aquifer and an associated canal in the west of the Thames Basin, southern England are examined and linked to agricultural and sewage sources and within river/canal process controls. The study area comprises the River Dun, the adjacent River Kennet and the Kennet and Avon (K&A) Canal. Large seasonal variations are observed for soluble reactive phosphorus (SRP) and dissolved silicon (Si) with low concentrations in the spring and summer times when biological activity is high. The K&A Canal shows the largest SRP and Si concentration declines. This reflects high biological activity coupled with higher temperatures and higher water residence times. The extent of SRP removal is examined in relation to organic (uptake/release with phytoplankton growth/decay) and, to a lesser extent, inorganic (SRP coprecipitation with calcite) mechanisms. Boron (B) is used as a tracer of sewage sources. Agricultural inputs of both dissolved and particulate P (PP) can be important particularly under conditions where the catchment is wet and near surface/overland flow is important: sewage treatment works effluent and septic tank discharges to groundwater also probably provide a major component of the SRP occurring within the water column. The canal, and to a lesser extent the river, acts as sink for P in sewage effluent sources due to the high biological activity especially during the spring and summer. The aquifer probably acts as a major sink for agricultural and septic tank inputs of P.     

Acute toxicity of unbleached kraft mill effluent (UKME) to the opossum shrimp, Neomysis americana smith

Ninety-six hour TL₅₀ values of unbleached kraft mill effluent (UKME) for Neomysis americana were found to range from concentrations of 3.29–6.85 per cent at 26–28°C and 3.90–7.30 per cent at 16–18°C. Differences between batches of effluent proved insignificant in experiments at each temperature regime. Furthermore, UKME did not lose its toxicity when stored for 5–7 days at 4°C. A concentration of 20 per cent effluent killed 100 per cent of the organisms in 8 of the 12 bioassays. Slope functions and confidence limits of TL₅₀ were calculated. Toxicity did not appear to be correlated with the Biochemical Oxygen Demand (BOD) of individual batches of raw effluent.     

The limitation of the ratio of fecal coliforms to total coliphage as a water pollution index

The fecal coliform populations of raw sewage, sewage lagoon effluent, and river water were determined using the most probable number technique. The total coliphage populations of the three water sources were determined using Escherichia coli B (ATCC 11303-1) host cells. The ratios of fecal coliforms to coliphage in the three water samples were 87:1, 4.2:1, and 0.15:1, respectively. The ratio of fecal coliforms to coliphage in stored raw sewage decreased from 87:1 to about 1:1 within 7 days at 20°C and within 28 days at 4°C. These changing ratios resulted from the greater longevity of the coliphage compared with that of the coliform bacteria. The use of the ratio of fecal coliforms to coliphage is not considered reliable as an index of when a fecal pollution event occurred because the ratio is influenced by prior contamination, presence of sediment, chlorination, and temperature.     

Studies on the effects of sewage effluent on gastropod populations in experimental streams

Population density, biomass, growth and reproduction rate of the gastropods Lymnaea peregra (Müller) and Potamopyrgus jenkinsi (Smith) were monitored over a 21 month period in three experimental earth channels, one carrying clean river water and the others 25 and 50% treated sewage effluent mixed with river water. Each channel was divided into riffle and pool stretches; the abundance and biomass of both species were higher in the riffles. The abundance and biomass of L. peregra were significantly greater (P < 0.01) in the riffle in the presence of effluent. Concentration of effluent did not have a significant effect on abundance or biomass. The abundance and biomass of P. jenkinsi were significantly greater (P < 0.001) in riffle and pool in the absence of effluent. In addition, the abundance and biomass of P. jenkinsi were significantly greater (P < 0.05) in the 25% effluent channel than in 50% effluent. No significant differences in the growth of L. peregra between channels were observed. The average number of eggs and of egg masses laid by L. peregra was significantly greater (P < 0.01) in riffle and pool in the presence of effluent. In the riffle, significantly more masses (P < 0.05) and more eggs per adult (P < 0.01) were laid in the 25% effluent channel than in 50% effluent. No differences were observed in the reproduction rate per adult of P. jenkinsi between the 0 and 25% effluent channels. It is concluded that population differences between channels are probably largely the result of differing mortality rates.