Aerobic Lagoon Research Articles

Impact of Seasonal Variation on Treatment of Swine Wastewater

Swine wastewater (agricultural wastewater) is normally stored in a storage holding tank for a certain time before released to the other treatment units, such as anaerobic lagoon and aerobic wetland. One of the characteristics for this treatment approach is that all the processes are open systems that are generally more passive in design and operation. As a consequence, seasonal variability including temperature and precipitation can have substantial impact on treatment efficacy and effluent water quality. This paper examines seasonal impacts of temperature on swine wastewater quality and treatment efficacy at a farm in East Leicester, Nova Scotia, Canada. During warm temperatures denitrification was noticeable in the anaerobic conditions, which would reduce the TSS removal rate from 76.6% in moderate temperatures to 42.1% in the warmest period recorded. Rainfall improved final effluent water quality, although this was shown to be through dilution rather than improvement of treatment efficacy. Following precipitation events the contaminant removals were negatively impacted in the aerobic lagoon, as BOD5 removal decreased from 61.6% before rainfall to 41.5% after rainfall, TSS from 71.4% to 59.3%, VSS from 73.4% to 59.3%, TKN from 59.9% to 42.1%, and NH4 +-N from 51.3% to 41.6%. In comparison to the aerobic conditions, the removal rates were increased for anaerobic condition with the rainfall dilution (e.g., TSS from 18.2% to 34.3%), which lead to an overall treatment improvement for the entire system. Thus the case study data presented in this paper provides an assessment of the operational and design issues that are particularly relevant for passive treatment systems that are used in the agriculture industry.

Use of Duckweed, Bentonite and Acid to Improve Water Quality of Effluent Discharge from Abattoirs

Intensive animal industries create large volumes of nutrient rich effluent, which, if untreated, has the potential for substantial environmental degradation. Aquatic plants in aerobic lagoon systems have the potential to achieve inexpensive and efficient remediation of effluent, and to recover valuable nutrients that would otherwise be lost. Members of the family Lemnaceae (duckweeds) are widely used in lagoon systems, but despite their widespread use in the cleansing of sewage, only limited research has been conducted into their growth in highly eutrophic media, and little has been done to systematically distinguish between different types of media. This study examined the growth characteristics of duckweed in abattoir effluent, and explored possible ways of ameliorating the inhibitory factors to growth on this medium. A series of pot trials was conducted to test the tolerance of duckweed to abattoir effluent partially remediated by a sojourn in anaerobic fermentation ponds, both in its unmodified form, and after the addition of acid to manipulate pH, and the addition of bentonite. Unmodified abattoir effluent was highly toxic to duckweed, although duckweed remained viable and grew sub optimally in media with total ammonia nitrogen (TAN) concentrations of up to 100 mg/l. Duckweed also grew vigorously in effluent diluted 1:4 v/v, containing 56 mg TAN/L and also modified by addition of acid to decrease pH to 7 and by adding bentonite (0.5%).

Aerobic degradation of 2,4,6-TCP content in ECF bleached effluent

Elemental chlorine-free (ECF) bleach effluents from kraft mill are characterised by: a chemical organic demand/biological organic demand (COD/BOD 5) ratio of 4, chlorophenol content with low chlorine substitution, and toxicity. The effect of increasing the concentration of 2,4,6-trichlorophenol (2,4,6-TCP) content in ECF bleaching sequence effluent on the degradative activity of bacterial communities present in an aerobic system treatment was studied. An aerobic lagoon (AL) was used as a typical secondary treatment of kraft-mill effluent. AL displays a high performance of BOD 5 degradation (up to 90%); however, only 40% of the COD was removed. Simultaneously, the AL system shows a high ability to biodegrade 2,4,6-TCP up to 237 mg/l day. Kinetic parameters of the 2,4,6-TCP biodegradation by aerobic bacteria were determined. The K s and K i values were 34.3 and 50 mg/l 2,4,6-TCP, respectively. Moreover, the tolerance of aerobic bacteria was observed up to 1.3 g/l 2,4,6-TCP.

Microbial removal of chlorinated phenols during aerobic treatment of effluents from radiata pine kraft pulps bleached with chlorine-based chemicals, with or without hemicellulases.

The removal of chlorophenolic compounds from kraft mill effluents bleached with chlorine (cBKME) or chlorine plus hemicellulases (bBKME) was studied in reactors of aerobic treatment lagoons. In these laboratory models, a stable microbial population removed biochemical oxygen demand at similar rates of the mill lagoon. Complete removal of nine chlorophenols and chloroguaiacols during microbial treatment of these effluents was detected by gas chromatography. Abiotic removal was only observed with 2,4-dichlorophenol and 2,4,5-trichlorophenol. There were no significant differences in degradative ability between microorganisms acclimated to grow in reactors fed with cBKME or bBKME. The latter had a lower content of adsorbable organic halogen and chlorophenols than cBKME. Microorganisms acclimated to cBKME or bBKME were only able to grow on phenol or guaiacol as sole carbon source. However, these microorganisms removed (0.1-0.5 mM) 4-chlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenoxyacetate with BKME as primary carbon source. Under these conditions, 2,4,6- and 2,4,5-trichlorophenol, 4,5-dichloroguaiacol, 4,5,6-trichloroguaiacol and tetrachloroguaiacol were not removed. These results suggest that the microbial removal of bleaching chlorophenols and chloroguaiacols during aerobic treatment, probably takes place only because of their very low concentration (1-200 ppb) in BKME.

Accumulation of organic solids in gravel-bed constructed wetlands

The effects of wastewater loading rate and planting with Schoenoplectus validus (soft-stem bulrush) on the accumulation of organic matter were investigated in four pairs of gravel-bed constructed wetlands. The planted and unplanted wetland pairs, each supplied with a different hydraulic loading of dairy farm wastewaters pre-treated in an anaerobic and aerobic lagoon, had received cumulative suspended solids loadings (∼ 82% volatile) of between ∼ 1.6 and 5.4 kg m−2 over a 22 month period. Vertical and horizontal gradients of organic matter accumulation were sampled by stratified coring, and the impact of solids accumulations on wastewater residence times investigated using bromide as a conservative tracer. Mean accumulations of organic matter in the unplanted wetlands ranged between 0.4 and 2.3 kg m−2, while those in the planted wetlands reached mean levels of nearly 4 kg m−2. Highest levels were recorded in influent zones (up to 9.5 kg m−2) and in the upper 100 mm of the substratum. The effective porosity of the highest loaded wetlands was markedly reduced compared to that in the lowest loaded wetlands, with mean retention times decreasing to around half of their theoretical values (corrected for evapotranspirational water losses). The planted wetlands retained higher apparent gravel porosity, despite greater accumulations of organic matter. High evapotranspiration rates during hot summer days, markedly extended retention times and increased tracer dispersion.

Accumulation of organic solids in gravel-bed constructed wetlands

The effects of wastewater loading rate and planting with Schoenoplectus validus (soft-stem bulrush) on the accumulation of organic matter were investigated in four pairs of gravel-bed constructed wetlands. The planted and unplanted wetland pairs, each supplied with a different hydraulic loading of dairy farm wastewaters pre-treated in an anaerobic and aerobic lagoon, had received cumulative suspended solids loadings (~ 82% volatile) of between ~1.6 and 5.4 kg m−2 over a 22 month period. Vertical and horizontal gradients of organic matter accumulation were sampled by stratified coring, and the impact of solids accumulations on wastewater residence times investigated using bromide as a conservative tracer. Mean accumulations of organic matter in the unplanted wetlands ranged between 0.4 and 2.3 kg m−2, while those in the planted wetlands reached mean levels of nearly 4 kg m−2. Highest levels were recorded in influent zones (up to 9.5 kg m−2) and in the upper 100 mm of the substratum. The effective porosity of the highest loaded wetlands was markedly reduced compared to that in the lowest loaded wetlands, with mean retention times decreasing to around half of their theoretical values (corrected for evapotranspirational water losses). The planted wetlands retained higher apparent gravel porosity, despite greater accumulations of organic matter. High evapotranspiration rates during hot summer days, markedly extended retention times and increased tracer dispersion.

Resistance patterns of e. coli strains isolated from domestic sewage before and after treatment in both aerobic lagoon and activated sludge

This work compares antibiotic resistance of 870 E. coli strains isolated from domestic raw sewage, in the effluent from aerobic lagoons and activated sludge plants. Efficiency of both treatment systems in removing faecal coliforms (FC) has also been evaluated. Reduction of FC was greater in the aerobic lagoon (99.99% in summer) than in the activated sludge system (91.30% in summer). Although the aerobic lagoon is efficient in removing faecal coliforms in comparisons with the activated sludge plant, it discharges these bacteria into receptor environments in larger (30.10 3 CFU/100 ml) or smaller quantities (9–10 2 CFU/100 ml) according to season. Among these FC, E. coli which was relatively high (on average 80%) constitutes a health problem when it is resistant to antibiotics. As for percentage of global antibiotic-resistance (evaluated by Gallery ATBG-method), the E. coli strains isolated from the effluent of the aerobic lagoon showed significantly higher antibiotic-resistance (34.66%) than those isolated from domestic sewage (23%). In the activated sludge, the percentage of antibiotic resistant strains (resistance to at least one antibiotic) showed seasonal changes in the inflow and outflow water samples. The increase of the percentage of antibiotic resistant strains of E. coli in the outflow of the lagoon system is probably related to the selection of antibiotic resistant strains by this kind of treatment. Transfer of antibiotic-resistance between E. coli strains can occur in the wastewaters treated by this system. Survival experiments on two strains of E. coli, E. coli resistant to seven antibiotics and E. coli O126:B16 sensitive to the 15 tested antibiotics, isolated from the environment, show the ability of resistant bacteria to survive better than sensitive ones in waste water treated in lagoons.

Anaerobic-Aerobic Lagoon Treatment of Kraft Mill Effluent for Enhanced Removal of AOX

Abstract A continuous-flow sequential anaerobic-aerobic lagoon treatment process was developed and evaluated for removal of adsorbable organic halide (AOX) from whole-mill kraft effluent at both laboratory and pilot-scale. The rationale underlying the development of the process was that the AOX removal efficiency of aerated lagoons currently in use might be significantly increased through relatively simple modification. Bench-scale studies showed that sequential anaerobic-aerobic treatment of whole-mill kraft effluent resulted in AOX-removal efficiencies of over 70% at hydraulic retention times (HRTs) of 10 days, 5 days and 2 days. In contrast, only 20%, 35% and 36% removal was obtained in a control aerobic lagoon. Pilot-scale studies showed that up to 65% removal of AOX from whole-mill kraft effluent was consistently obtained at HRTs ranging from 5 to 10 days. This compares with typical AOX removal efficiencies in conventional aerated lagoons of about 25%. Conversion of the anaerobic section in the pilot-scale lagoon from a simple sludge blanket to a combination of sludge blanket and submerged biofilm further increased AOX removal efficiencies to about 70%.

Anaerobic Treatment of Domestic Sewage and Wastewater

Recent UASB-pilot plant and full scale experiences show that anaerobic pre-treatment is feasible for sewage and domestic wastewaters in tropical regions. This offers developing countries the unique opportunity to become completely self-sufficient in this respect. UASB-systems can be applied at very small and at very big scale, i.e. for off-site and (house and community) on-site treatment. Results obtained in pilot plant and full scale installations demonstrate that these systems are quite effective in removing and stabilizing organic pollutants at liquid detention times as low as 4 hrs, i.e. a BOD reduction up to 75-95 % can be achieved, while an almost complete treatment can be accomplished by combining the method with a small aerobic lagoon. Instead of consuming high grade energy, these systems produce energy. Moreover the excess sludge production is very low, while also the dewatering characteristics of the sludge are excellent.

Treatment Technologies for Organochlorine-Containing Sludges and Concentrates from External Treatment of Pulp and Paper Wastewaters

Literature data and results from current Swedish research have been used to compile characteristics of and disposal methods for sludges and concentrates from external treatment of wastewaters from the pulp and paper industry. Very little sludge from aerobic lagoon treatment in Sweden is handled, and most of the solids are deposited in the receiving waters. In North America, Finland and Japan, where activated sludge treatment is used to a great extent, sludge handling is an important part of kraft mill effluent treatment. Typically, 5-15 kg of dry solids has to be handled per ton of pulp with a process discharge of 15-20 kg of BOD5/t90- For chemical coagulation, the amounts of sludges produced are higher, typically 40-80 kg dry solids/t90. Especially in Japan, chemical coagulation is used to a great extent. Laboratory and pilot- plant experiments with Ultrafiltration of alkaline stage and total bleach plant effluents suggest that concentrates with a total solids content of approximately 20 and 50 kg dry solids/t90 are produced. The concentrations of organochlorine compounds in sludges and concentrates have not hitherto been well documented, and nor have environmental effects of different disposal methods. Chlorinated phenols, catechols and guaiacols have been found in variable concentrations; chlorinated dibenzodioxins and furans have also been detected. Vacuum filters and especially belt filter presses have been used to dewater sludges. Typical dry solids concentrations achieved vary from 20-35 % for primary sludges to 15-20 % for secondary sludges. Anaerobic digestion may be applied before dewatering of sludges, and methane yields of 200-400 1 CH4/kg VSrem have been reported. Sludge has been disposed of in landfills or incinerated. Leachates from landfilling of pulp and paper industry sludges may contain high levels of soluble organic material, but available information suggests that organochlorine compounds do not leach to a substantial extent. Incineration of pulp mill sludges and concentrates seems to be an increasingly attractive method.

Extraction of energy from an aerobic farm waste lagoon

The practical and economic aspects of heat recovery from a full-scale aerobic waste lagoon are considered. The heat recovery system consists of a water to water heat pump, of 21·6 kW output delivering the heat into pig farrowing accommodation on a commercial farm. The aerobic lagoon maintains a temperature of 35°C, summer and winter, and the heat pump delivers hot water at 55°C to a radiator heating system. The performance of the system was monitored for one year and an assessment is made of the likely costs and benefits for this particular farm. If the waste system is installed to provide some degree of treatment and to control odour, then the capital and running costs need not be debited to the heat recovery system. In this circumstance, the additional costs of the heat pump and heat exchanger may be recovered in 3–4 years.

Effect of Herbicides on Performance of Aerobic Dairy Lagoons

ABSTRACT THE herbicides glyphosate, bromacil, and dalapon were assessed for their affect on the oxygen uptake of microorganisms from an aerated dairy lagoon at 20 C. The maximum recommended addition of herbicide ac-tive ingerdient to a lagoon is: glyphosate (isopropyl amino salt)0.42 mg/L; bromacil3.70 mg/L; and dalapon (85.8 percent Na salt and 14.2 percent Mg salt)1.95 mg/L. In addition, microorganism isolates from the aerobic dairy lagoon were incubated under aerobic and anerobic conditions at room temperature to assess the effects of the herbicides. Under aerobic in-cubation, it was found that neither herbicide type nor herbicide concentration affected isolate growth. Under anaerobic incubation, both inhibition and stimulation effects were found with gram-positive rod organisms be-ing least affected.

Characterization and agricultural utilization of swine waste lagoon effluents

This investigation was conducted to determine the elemental composition of effluents from three anaerobic swine waste lagoons and one aerobic swine waste lagoon and to evaluate effects of effluent application on growth of corn (Zea mays L.) Wide variation occurred in the elemental composition of effluents among the four lagoons and among four sampling dates from each lagoon. Use of these effluents as irrigation water would lead to application of a wide range in amounts of nutrients to soil. Effluent application increased corn grain yield on a Woodstown loamy fine sand. This yield increase was attributed to alleviation of moisture stress and to correction of N deficiency.

Erratum: Antibiotic resistance patterns of fecal coliforms isolated from domestic sewage before and after treatment in an aerobic lagoon

Erratum: Antibiotic resistance patterns of fecal coliforms isolated from domestic sewage before and after treatment in an aerobic lagoon

Antibiotic resistance patterns of fecal coliforms isolated from domestic sewage before and after treatment in an aerobic lagoon

The resistance of 260 strains of fecal coliforms, isolated from raw domestic sewage and aerobic lagoon effluent, to ampicillin, aureomycin, chloromycetin, gentamicin, streptomycin, sulfadiazine, and tetracycline, was determined. Aerobic lagoon treatment produced a 20-fold reduction in the fecal coliform numbers. No statistically significant difference in antibiotic resistance was observed between the fecal coliforms found in raw sewage and in lagoon effluent despite a trend towards the loss of resistance in the latter. Antibiotic resistance, either single or multiple, did not contribute to, or detract from, bacterial survival in the aerobic lagoon. Of the isolates, 15% showed resistance to two or more antiobiotics.

Salt Removal Efficiencies on Land Disposal of Swine Waste

Swine waste aerobic lagoon effluent was sprinkled overland and the runoff water was collected. Both the waste effluent and the runoff water were analyzed for nitrate, ammonia, chloride, suspended solids, BOD, and specific conductance. Removal efficiency of nitrate dropped from 62% to 32%, on prolonged disposal of swine waste effluent, in 6 months. Data for suspended solids and specific conductance support these results for nitrate removal efficiency. Removal efficiencies for ammonia and chloride were higher and showed a very small decrease with time. BOD removal efficiency was 95% throughout the 6-month period of the study. The system showed signs of “overloading” for nitrate removal but not for BOD removal.

Survival of S. Typhi in Sewage Oxidation Ponds

Tests indicate that Salmonella typhi survive for longer periods in anaerobic than in facultative lagoons. Laboratory tests on the survival of Salmonella typhi were made in several columns, some of which simulated conditions in anaerobic lagoons, other facultative (or aerobic) lagoons. Lagoons which were in use were used as a source of test media to fill the columns. During the tests on the facultative columns, daily additions of sterile settled sewage were made at a biochemical oxygen demand (BOD) loading of 50 lb per acre per day. Nutrient addition continued after inoculation with Salmonella typhi. The anaerobic column loadings were varied from 500 lb to 6,000 lb of BOD per day, by addition of sterile raw sludge. After inoculation of these columns with Salmonella typhi no further nutrient was added. Survival in the facultative case (low loadings) was of the order of 30 hr. Survival time in the anaerobic columns increased with increases in initial (or interim) loadings to 4,000 lb of BOD per acre per day. Preliminary tests using Serratia Marcescens as an indicator organism in place of Salmonella typhi were unsuccessful. Bismuth sulphite agar proved suitable as a differential media for enumeration of Salmonella typhi in sewage lagoons.