The use of hydrobia jenkinsi to detect intermittent toxic discharges to a river

Heavy metals and dieldrin concentrations were measured during 1976 and 1977 in the River Holme and some of its tributaries, West Yorkshire, England. The concentration of dieldrin and certain heavy metals were thought to be high enough to have a biological effect. The survival of the operculate gastropod H. jenkinsi in simulated River Holme water artificially spiked with dieldrin and heavy metals was assessed. The toxic responses noted during these experiments correlated closely with the response found when H. jenkinsi was exposed to collected polluted river samples. In situ toxicity of caged H, jenkinsi sited below pollutant discharges appeared to be capable of detecting intermittent discharges contaminated with certain heavy metals notably copper and hexavalent chromium. Deaths in situ could not, however, be solely attributed to these poisons. The lack of toxic response to dieldrin at concentrations in excess of 30,000 ng 1⁻¹ suggests a dual indicator system using H. jenkinsi and an organism suscpetible to pesticides would be needed to monitor pollution in the River Holme. This aspect is briefly discussed.     

An evaluation of the potential toxicity of treated bleached kraft mill effluent to striped bass (Morone saxatilis walbaum) larvae exposed through metamorphosis to the juvenile stage

Twenty-day-old striped bass (Morone saxatilis) larvae were exposed to a range of treated bleached kraft mill effluent (BKME) concentrations from 0 to 20% effluent by volume (v/v) under continuous flow test conditins. The experimental test concentrations in the 2–20% BKME test aquaria had a BOD₅ which ranged from < 1 to 5 mg l⁻¹, TSS 12–17 mg l⁻¹, and true color 35–416 mg l⁻¹. Bleached kraft mill effluent did not kill larvae exposed to it for 20 days through metamorphosis to the juvenile stage. The BKME did not alter growth in length, weight or condition factor in larvae over the 20-day exposure period as determined by multiple regression analysis. A linear regression analysis on the dry weight data at Day 20 only, however, indicated a trend of decreasing weight with increasing BKME concentration. Effluent-exposed larvae also developed normally during the 20-day study. All individuals examined completed the transformation from postlarvae to juveniles by the age of 40 days.     

The effect of nutrition on the response of field populations of the calanoid copepod Acartia tonsa to copper

Continuous flow toxicity tests were conducted on field populations of adult Acartia tonsa collected from Narragansett Bay. Potential algal food at the collection site was estimated from ATP and chlorophyll analysis. There was positive correlation (P < 0.01) between chlorophyll a and ATP. Integration of these data with quantitative zooplankton analysis established that A. tonsa had a significant grazing effect on algal biomass (P < 0.05). The natural population dynamics of A. tonsa during this period were assessed from microscopic analysis of tow material.The sensitivity of A. tonsa to total copper ranged from 9.0 to 78.0 μg l⁻¹ for 72 h LC50's. Results show an inverse correlation (P < 0.05) between the log LC50 and adult A. tonsa density at the time of collection. The relationship between A. tonsa sensitivity to copper and the food ration (algal density/A. tonsa density) has been described by a quadratic function which has a correlation coefficient of 0.78. This indicates that the log LC50 increases with increasing food ration up to a point and then remains constant. A comparison of confidence intervals about the LC50's indicates greater variability in the response of field animals compared to previous studies with cultured populations. This data suggests that field populations of A. tonsa can be expected to exhibit a wide range of sensitivity to other pollutants. Sensitivity is strongly correlated with population density and food ration.     

The macroinvertebrate faunas of riffles and pools

Macroinvertebrate data from studies of rivers, principally in upland areas, of North America (9) and U.K. (8) were examined to identify differences in the faunas of riffles and pools. Overall the number and representation of taxa in the two habitats was similar although some organisms (e.g. Simulium, riffles; Corixa, pools) may characterise each habitat. Significantly higher mean total densities were detected in riffles compared to pools and this confirmed the general conclusions from a number of individual studies: significantly higher densities in pools were never reported. The relative abundance of major groups (Orders) in each habitat was variable: in general, Ephemeroptera formed a higher proportion of the total density in riffles than pools and the reverse was found for Diptera. Only the Ephemeroptera showed significant differences in density between the two habitats, riffles supporting higher densities than pools. Considering families, only Baetidae and Simuliidae showed significant differences in density, riffle density being greater than pool density. Community analyses, commonly used in biological surveillance, indicated that it is unlikely that major misclassification of sites will result from the use of data collected from one habitat (riffle/pool) only. Further studies are required at lowland sites to test the general applicability of the conclusions.     

Testing the potential of aquatic plants to treat abattoir effluent

The potential of 3 genera of emergent aquatic plant species (Typha spp, Phragmites and Scirpus) to ameliorate effluent from a poultry abattoir was evaluated in an experimental trench system. Three plastic-lined trenches containing Typha (two species), Phragmites and Scirpus plants in a gravel substrate were constructed near the abattoir. Effluent was allowed to percolate, with retention times of 2.7–3.6 days, through the trenches. The quality of the inflowing and outflowing effluent was compared by a regular sampling program for suspended solids, conductivity, turbidity, pH, dissolved oxygen, Na, K, Cl, N and P concentrations. The importance of water loss by evapotranspiration was investigated.Comparing the inflow to outflow, each trench system successfully reduced the suspended solids (83–89%), turbidity (58–67%), total nitrogen (14–56%) and total phosphorus (37–61%) concentration of the effluent while maintaining an acceptable pH and in the case of the Phragmites and Scirpus systems oxygenating the anaerobic inflow. Conductivity increased in the Typha and Phragmites trenches. If a correction is made for water lost by evapotranspiration, the three experimental trench systems reduced the nitrogen (42–75%), phosphorus (68–79%), sodium (7–34%), potassium (9–56%) content of the effluent. The chloride content of the effluent in the Phragmites system was increased by 15% but was reduced by 31 and 53% in the Typha and Scirpus systems respectively. The results from this initial experiment give an indication of the relative abilities of the three plant systems to treat the wastewater from the abattoir. Of the three, that containing the Scirpus was superior.     

Towards a better understanding of high rate biological film flow reactor theory

On the assumption that performance of biological film flow reactors is independent of oxygen transfer, a theoretical extension of a mathematical model (after Ames) is described. This predictive and interpretive model incorporates both mass transfer-limitations between biomass and liquid film, and kinetic biological reaction rate of organic “food” utilization.Given general boundary conditions for the differential equations describing the mass transfer process, it is shown that: C_e = C_r + (C_l − C_r.exp(−K_m D/Q) where by definition: C_t = α C_s + C_r1/K_m = 1/K_LA_γ + α/Kx.For an influent concentration biochemical oxygen demand (C_i) and resultant effluent concentration (C_e) obtained during film flow through a packed media depth (D), the Model proposes that the residual concentration (C_r) is a function of surface irrigation rate (Q) and biomass activity. If this term is negative, adsorption occurs; while if positive, desorption from the biomass film at concentration (C_s) takes place.An overall mass transfer coefficient (K_m) is defined by a series equation where the usual mass transfer coefficient (K_L) is primarily a function of Reynolds Number [surface irrigation rate (Q) and specific surface area (A_V)], Schmidt Number (diffusivity of organic “Food”) and concentration. “Food” utilization at active sites on the biological film is governed by a specific adsorption coefficient (α) and explained by a Langmuir analogy. Biological conversion of “food” is described by a kinetic rate constant (K), while the necessary oxygen is defined by (X).This predictive model was developed from a wide range of pilot plant data, successfully tested further on a variety of published results and on actual full scale operating plants.Parameters derived from this Model, in terms of Height of Transfer Unit and Kinetic Reaction coefficient, characterize organic “treatability” for a variety of wastes.     

Use of photosynthetic bacteria for hydrogen sulfide removal from anaerobic waste treatment effluent

The feasibility of using photosynthetic bacteria to remove H₂S from anaerobic waste treatment effluent was investigated by growing fixed films of photosynthetic bacteria in a packed column or in a submerged tube system (“phototube”). Growth and enrichment for these organisms depended on constant illumination, anaerobic conditions and a substratum for attachment of the bacteria. Both systems were operated as flow-through processes using effluent from anaerobic (upflow) filters.Results showed that photosynthetic bacteria in fixed films can be effectively used for H₂S removal. Removal efficiencies of 81–95% were obtained on a 24-h retention time. Residual H₂S remained in the process effluent. The submerged “phototube”, showed dramatic improvement over the column, yielding a final effluent completely devoid of H₂S, at significantly shorter retention times and higher loading rates than the column. Performance appeared dependent on cell-H₂S contact and adequate illumination. The green photosynthetic sulfide-oxidizing bacterium, Chlorobium, was identified as a common organism in this phototube.This biological sulfide removal process offers the following advantages over currently used physical-chemical techniques: simplicity, no need for aeration or chemical additives and odor-free. Much research in process design is necessary before pilot or full scale application of the technique is possible.     

Long-term effects of treated domestic wastewater on brown trout

A 12-month bioassay was conducted to determine the effects of unchlorinated, treated, domestic wastewater on survival, growth, swimming performance, and gill tissue of brown trout (Salmo trutta). Ammonia was the toxicant of concern, because the facility's effluent periodically exceeded the U.S. Environmental Protection Agency's (EPA) recommended criterion. Juvenile brown trout (initial weight = 2 g), which were exposed to six concentrations (0–37%) of effluent, were fed a restricted ration, so that growth rates were similar to those of wild stream residents. At the highest effluent concentration, monthly mean concentrations of un-ionized ammonia ranged from 0.004 to 0.055 mg l⁻¹ NH₃---N (at. wt = 14); these concentrations exceeded the EPA criterion of 0.016 mg l⁻¹ about 40% of the time. There were no significant effects of effluent concentration on survival, growth, or swimming performance of brown trout, but the degree of damage to gills was directly related to effluent concentration.     

Dissolved organic carbon during a spring diatom bloom in Lake Mossø, Denmark

The concentration and molecular weight composition of dissolved organic carbon (DOC) was measured during a spring diatom bloom in eutrophic Lake Mossø, Denmark. The concentration fluctuated between 5.2 and 7.2 mg Cl⁻¹. No relationship between DOC concentrations and phytoplankton biomass or primary production was observed. Diurnal variations of a magnitude similar to variations on a weekly basis were found. A decomposition experiment showed the labile fraction to be of a magnitude similar to the diurnal variation, i.e. 0.7 mg Cl⁻¹. By gel filtration (Sephadex G-50 and G-15) it was shown that 70–90% of the DOC pool was <700 daltons and probably <300 daltons. The labile fraction consisted of low molecular weight compounds.     

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.     

Effects of mixing velocity on anaerobic fixed film reactors

Four laboratory-model upflow anaerobic fixed film reactors (AFFR 1, 2, 3 and 4) treating landfill leachate were subject to identical volumetric organic load (7 kg COD m⁻³ d⁻¹) and hydraulic retention time (3d), but the contents in each unit were continuously recirculated for 10 months at four different velocities, respectively, of 21, 66, 680 and 3063 cm h⁻¹. The objective was to assess the effects of such mixing velocities (ν) on COD removal efficiencies (E), mean cell residence time (MCRT) and substrate utilization rate (U expressed as g COD removed d⁻¹ g⁻¹ VSS). The results showed that the relationships between E and ν and MCRT and ν were inverted U-shaped curves. The two middle reactors (AFFR 2 and 3) had near-optimum velocities (ν₂ and ν₃) with maximum E values of 88–89%. AFFR 4 had a high value of ν scouring biofilm on the biorings, resulting in higher concentrations of SS, VSS and COD in the effluent. All four reactors had nearly similar values of U (1.85–2.14 g COD d⁻¹ g⁻¹ VSS). The value of ν₁ (AFFR 1) was too low to enhance performance and ν₄ was too high to retain the biomass. The optimum recycle velocity, under the test conditions, was in the range of 66–680 cm h⁻¹.     

The application of critical state soil mechanics to the mechanical behaviour of porous sandstones

The mechanical properties of three cohesive sandstones of different porosities (φ) and average grain diameters (R) have been investigated. These were Tennessee sandstone (φ=0.07), Darley Dale sandstone (φ=0.12), and Penrith sandstone (φ=0.25). Unconfined uniaxial compression, constant displacement rate triaxial, and hydrostatic experiments were conducted. Yield stress data produced approximately circular envelopes that decreased in size with increasing porosity or grain size when plotted in the differential stress versus effective mean stress (Q−P) space. Normalization of these data with respect to the hydrostatic grain crushing pressure (P^*) resulted in a unique yield envelope for sandstone. Extending these data into the Q–P–φR space allows the principles of critical state soil mechanics to be applied. The critical state line for porous sandstone (the crestal line of the yield surface) appears to correspond to the transition from dilatant behaviour with localized faulting at low effective mean pressures (P/P^*<0.5), to pervasive cataclastic flow at high effective mean pressures (P/P^*>0.5). Post-yield, deformation progresses towards the critical state as observed by constant volume deformation. The critical state model developed for soil mechanics can be applied to make generalizations about the deformation of cohesive, porous sandstones. The expected behaviour of any porous sand appears to be predictable to a useful degree from a knowledge of P^*, which can be estimated from the simple parameters of porosity and mean grain size.Sensitivity to the presence of water, attributed to sub-critical crack growth, was observed in hydrostatic and uniaxial compression tests in all rock types tested. Considerable strength and elastic anisotropy was also observed.     

A comprehensive study on the biological treatabilities of phenol and methanol—I. Analysis of bacterial growth and substrate removal kinetics by a statistical method

An unbiassed statistical method was developed to evaluate kinetic parameters in the biological oxidation of wastewaters. Through the statistical analyses of the biological oxidation kinetics, it was shown that the kinetic equations satisfactorily described the bacterial growth and substrate removal kinetics where X is biomass concentration, S is substrate concentration, t is time, a is cell yield coefficient, k_d is cell decay coefficient, K_s is Michaelis-Menten constant, and k is substrate removal rate coefficient. The coefficients K_s and a changed with temperature insignificantly while k and k_d were closely related to it. The temperature independent coefficients K_s and a were estimated to be 236 mg 1⁻¹ (standard deviation, σ = 70 mg 1⁻¹) and 1.21 (σ = 0.06) respectively for phenol, and 2330 mg 1⁻¹ (σ = 1410 mg 1⁻¹) and 1.25 (σ = 0.45) respectively for methanol based on total organic carbon (TOC) and volatile suspended solids (VSS). The oxygen utilization rate can be formulated as where Rr is the oxygen utilization rate (mg 1⁻¹ O₂ time⁻¹), as′ is a coefficient designating oxygen requirement per substrate utilized, and b′ is a coefficient designating oxygen requirement per biomass for endogeneous respiration. The coefficient a′ was 1.39 for phenol and 2.23 for methanol, and b′ was 1.42 k_d for both substances based on TOC and VSS.     

The effects of depressed pH on flagfish reproduction, growth and survival

Breeding communities of flagfish, Jordanella floridae, were exposed to northern Ontario lake water (hardness 28 mg l⁻¹ CaCo₃) adjusted to depressed pH levels of 6.0, 5.5, 5.0 and 4.5. Control water (pH 6.8) received no acid treatment. Egg production, egg fertility and fry growth was impaired (P < 0.05) at all exposure levels. Flagfish fry survival was reduced (P < 0.05) at pH 5.5 and 5.0 and no fry survived at pH 4.5. Variability of hatching in all treatments precluded any identifiable hatching response to depressed pH. Reduction in the reproductive processes monitored indicated the following order of sensitivity: egg production > fry survival > fry growth > egg fertility.Results of this study coincide with reproductive investigations on brook trout and fathead minnows indicating the “no effect” level of pH depression for successful reproduction to be pH 6.5.     

Anaerobic treatment of phenolic coal conversion wastewater in semicontinuous cultures

High strength wastewater (7600 mg 1⁻¹ phenolics) from the H-coal liquefaction process was diluted and fed to anaerobic, methane-producing cultures. Total phenolic concentrations of 150 and 300 mg 1⁻¹ were added to 50 ml semicontinuous cultures with hydraulic retention times of 12.5, 16.7 and 25 days. The rates of methane production and effluent concentrations of three fermentable phenolics (phenol, p-cresol and m-cresol) were monitored over a 188-day period. After acclimation to the wastewater, stable periods followed during which each of the six cultures removed essentially all of these fermentable phenolics. The duration of the stable periods decreased with increasing phenolic mass loading rates. m-Cresol was the first phenolic to appear in the effluent and its presence served as the first indicator of reduced phenolic removal capability. The effluent m-cresol concentrations from cultures receiving 300 mg 1⁻¹ total phenolics followed simple washout curves suggesting that its degradation stopped abruptly. Later, p-cresol and ultimately phenol appeared in the effluents from the cultures which received the highest phenolic mass loadings.     

Effect of temperature and pH value on the growth-rate constants of nitrifying bacteria in the activated-sludge process

The specific growth rates of nitrifying organisms were determined under non-equilibrium conditions in laboratory-scale activated sludge plants at three temperatures and six pH values. The highest growth rate for the first stage (to nitrite) was 0.61 d⁻¹; no nitrification was observed over a 7 week period at pH 6.0 at any temperature, indicating a μ value of <0.06 d⁻¹. Fewer data were obtained for the second stage (to nitrate); in all but one of ten comparisons the specific growth rate was lower (by an average of 16%) than for the first stage. The effects of temperature and pH value were not as expected probably because of greater effects resulting from the differences in composition and strength of the sewages used.It is shown that calculations of μ from simple measurements made on full-scale plants can give an early warning of harmful changes in the aeration tank well before the concentration of ammonia in the effluent increases.     

Predictive model for treatment of phenolic wastes by activated sludge

The current investigation was made to determine whether a model using cell recycle concentration as a major control parameter is applicable to inhibitory substrates such as phenol. Based upon preliminary studies, the Haldane equation was selected to relate specific growth rate and substrate concentration. Seven long-term pilot plant runs were made at different growth rates. Effluent and control parameters were measured frequently. The maintenance constant was obtained from the pilot plant data. The three Haldane equation constants and the true cell yield were estimated from pilot plant and batch data.The model gave satisfactory predictions with respect to biomass production (X and X_w) and effluent COD, based on the ΔCOD method. The predicted phenol concentration, although very low, was higher than the minute levels observed in the pilot plant effluent (±0.1 mg l⁻¹); possible reasons not directly related to growth are explored, e.g. retention of unmetabolized phenol in the sludge.     

Some growth parameters of haliscomenobacter hydrossis (syn. streptothrix hyalina) a bacterium occurring in bulking activated sludge

A study has been made of the kinetics of two strains of the sheath-forming bacterium Halisco menobacter hydrossis (syn. Streptothrix hyalina) by growing the bacteria axenically in continuous culture, with glucose as the limiting substrate. The maximum specific growth rates were approx. 0.05 h⁻¹ for strain AN and 0.09h⁻¹ for strain AZ, corresponding to minimum doubling times of 14 and 9h, respectively. Depending on the history of the population, appreciably lower values were found in batch experiments. The maintenance coefficient was low, 20 and 21 mg glucose (g biomass)⁻¹ h⁻¹ for strain AN and strain AZ, respectively. The “true” yield coefficients were 0.59 and 0.42 g biomass (g glucose)⁻¹, for strain AN and strain AZ, respectively.     

Linking biokinetics and consumer–resource dynamics of zinc accumulation in pond abalone Haliotis diversicolor supertexta

A dynamic model that links biokinetics and consumer–resource dynamics for describing zinc (Zn) accumulation in abalone Haliotis diversicolor supertexta has been developed and then applied to Zn data from real abalone farms. The biokinetic parameters used in this study, uptake and depuration rate constants of abalone and their food source, red alga Gracilaria tenuistipitata var. liui, were obtained from a laboratory 14-d exposure experiment. We carried out a sensitivity analysis of the model by using the fractional factorial design technique, taking into account the influence of consumer–resource-related parameters such as growth and death rates and biomass and biokinetic parameters characterized by bioconcentration factor. Results indicate that the response time of biomagnification dynamics of Zn accumulation in abalone was influenced mainly by the growth rate of algae and biomass and the death rate of abalone and by interactions algae biomass and abalone death rate and abalone and algae biomass. New algae production results in substantially higher values of biomagnification factor. The linked model was then applied to field observations from a real-life situation of variable Zn concentrations occurring in abalone farms. Simulation results show that the predicted values are within a factor of 2 of the measured values (% errors range from 5.3±4% to 44.1±8%). Both model analysis and model application to the abalone farms suggest that the linking influences between biokinetics and consumer–resource dynamics support Zn accumulation in H. diversicolor supertexta and in G. tenuistipitata var. liui as functions of Zn concentration in water and abundance of food occurring in abalone farms.     

Palm oil refinery wastes treatment

Effluent from the refining of crude palm oil was subjected to physical-chemical and biological treatment. An inclined corrugated parallel plates oil separator spaced at 25 mm was used with hydraulic loading rates of 0.2, 0.5 and 1 m³ m⁻²-h. 91% oil and grease removal could be achieved at 0.2 m³ m⁻²-h. Coagulation and flocculation carried out on batch samples after oil and grease separation revealed that with 100 mg l⁻¹ alum addition BOD was reduced from 3500 to 450 mg l⁻¹ and COD from 8600 to 750 mg l⁻¹ after 30 min settling. Higher doses of alum and doses of polyelectrolyte, activated carbon and sodium hypochloride did not yield significant additional reductions in BOD and COD. Batch dissolved air flotation (DAF) removed 90% of the suspended solids with 2.7% solids in the thickened sludge at an A/S ratio of 0.014. This method yielded the similar effluent quality as the inclined corrugated plates oil and grease separator. Field data from a DAF plant compare closely with data achieved in this study. Activated sludge treatment on the effluent from the oil separator yielded a BOD of 46 mg l⁻¹ with a loading rate of 0.3 g BOD (g MLVSS)⁻¹-day. Total dissolved solids (TDS) remained high and removal through coagulation and chemical oxidation brought the COD level down to around 180 mg l⁻¹. Biokinetic coefficients Y, k_dK and K₃ were found to be 0.85 g VSS (g BOD)⁻¹, 0.016 day⁻¹, 0.12 g BOD (g VSS)⁻¹-day and 510 mg l⁻¹ BOD respectively.