Innovative Technology of COD and BOD Reduction from Coffee Processing Wastewater Using Avocado Seed Carbon (ASC)

The study estimated the efficiency of Avocado seed carbon (ASC) for chemical oxygen demand (COD) and biochemical oxygen demand (BOD) reduction from coffee processing wastewater. It was performed under batch mode conditions to investigate the optimum operating conditions and efficiency for COD and BOD reduction with ASC compared with commercial activated carbon (CAC). Adsorption isotherm study was also performed and it was found that the values of regression coefficient (r ²), adsorption capacity (k), and adsorption intensity (1/n) for COD and BOD reduction with ASC were comparable to those of CAC. Under optimum operating conditions, the maximum percentage reduction of COD and BOD concentration using ASC was 98.28% and 99.19%, respectively and with CAC was 99.12% and 99.45%, respectively and hence adsorption capacity of ASC is comparable with that of CAC. Thus, this technique may be a good option for treatment of domestic wastewater.     

The Impact of Rainfall on Flows and Loadings at Georgia’s Wastewater Treatment Plants

An assessment of influent and effluent data from 24 wastewater treatment plants (WWTPs) in the state of Georgia with design capacities of 37,850 m³/d (10-mgd) or greater was undertaken. Twelve months of operating data from the 2003 calendar year were evaluated. The objectives of the study were to determine the effect of rainfall intensity on the volumetric flow rate to each WWTP and to determine the relationship between flow rate and the influent five-day, biochemical oxygen demand (BOD₅) and total suspended solids (TSS) concentrations. The relationships between rainfall intensity and influent BOD concentration, rainfall intensity and influent TSS concentration, influent BOD loading and effluent BOD concentration, and influent TSS loading and effluent TSS concentration were also evaluated. Moderate to strong correlations were observed between rainfall intensity and volumetric flow rate, volumetric flow rate and influent BOD and TSS concentrations, average monthly rainfall intensity and influent BOD and TSS concentrations, and between influent BOD and TSS loadings and effluent BOD and TSS concentrations. Weak correlations were observed for some of the relationships when applied to the complete data set however, stronger correlations were achieved by performing statistical analyses of variance and pooling subsets of the data. Peaking factors for flows and loadings were similar to those reported in the literature.     

Aerobic Biological Treatment of Chestnut Processing Wastewater

Chestnut agro-industrial companies consume a high volume of water for washing and processing fruit, generating a large volume of wastewater. This work studied the biodegradation of chestnut processing wastewater through aerobic assays, varying substrate, and biomass concentrations. In general, this wastewater presents a good biodegradability, especially in experiments with relatively low chemical oxygen demand (COD) (0.4 and 0.6?g O₂ L^?1) allowing a COD removal of 85?C90?%. The best results were obtained in the reactor initially loaded with 2?g?L^?1 of biomass and 0.4 or 0.6?g O₂ L^?1 of COD. These experiments also showed high COD removal rates: 4.25 and 3.88?g COD g^?1 volatile suspended solids (VSS) h^?1, respectively. The sedimentation rate, evaluated for different initial values of biomass (1, 2, and 3?g?L^?1), always presented higher values in the experiments with 2 and 3?g?L^?1 of biomass, regardless of the initial COD value used. After comparing different kinetic models (Monod, Contois, and Haldane), it was observed that the Haldane inhibition model satisfactorily describes the COD biodegradation. AQUASIM software allowed calculating the kinetic constant ranges: K _s, 1.59?C6.99?g COD L^?1; ?? _max, 25?C40?g COD g^?1 VSS day^?1; and K _i values, 0.07?C0.11. These kinetic constants corresponds to maximum rates (??*) between 1.48 and 4.25?g COD g^?1 VSS day^?1 for substrate concentrations (S*) from 0.38 to 0.88?g COD L^?1.     

Electrochemical Production of Ferrate (Iron VI): Application to the Wastewater Treatment on a Laboratory Scale and Comparison with Iron (III) Coagulant

This paper presents a comparative study of the performance of ferrate(VI), FeO ₄ ^2? , and ferric, Fe(III), towards wastewater treatment. The ferrate(VI) was produced by electrochemical synthesis, using steel electrodes in a 16 M NaOH solution. Domestic wastewater collected from Hailsham North Wastewater Treatment Works was treated with ferrate(VI) and ferric sulphate (Fe(III)). Samples were analysed for suspended solids, chemical oxygen demand (COD), biochemical oxygen demand (BOD) and P removal. Results for low doses of Fe(VI) were validated via a reproducibility study. Removal of phosphorous reached 40% with a Fe(VI) dose as low as 0.01 mg/L compared to 25% removal with 10 mg/L of Fe(III). For lower doses (<1 mg/L as Fe), Fe(VI) can achieve between 60% and 80% removals of SS and COD, but Fe(III) performed even not as well as the control sample where no iron chemical was dosed. The ferrate solution was found to be stable for a maximum of 50 min, beyond which Fe(VI) is reduced to less oxidant species. This provided the maximum allowed storage time of the electrochemically produced ferrate(VI) solution. Results demonstrated that low addition of ferrate(VI) leads to good removal of P, BOD, COD and suspended solids from wastewater compared to ferric addition and further studies could bring an optimisation of the dosage and treatment.     

Optimization of Petroleum Refinery Wastewater Treatment by Vertical Flow Constructed Wetlands Under Tropical Conditions: Plant Species Selection and Polishing by a Horizontal Flow Constructed Wetland

Typha latifolia-planted vertical subsurface flow constructed wetlands (VSSF CWs) can be used to treat petroleum refinery wastewater. This study evaluated if the removal efficiency of VSSF CWs can be improved by changing the plant species or coupling horizontal subsurface flow constructed wetlands (HSSF CWs) to the VSSF CW systems. The VSSF CWs had a removal efficiency of 76% for biological oxygen demand (BOD₅), 73% for chemical oxygen demand (COD), 70% for ammonium-N (NH₄⁺-N), 68% for nitrate-N (NO₃^?-N), 49% for phosphate (PO₄^3?-P), 68% for total suspended solids (TSS), and 89% for turbidity. The HSSF CWs planted with T. latifolia further reduced the contaminant load of the VSSF CW-treated effluent, giving an additional removal efficiency of 74, 65, 43, 65, 58, 50, and 75% for, respectively, BOD₅, COD, NH₄⁺-N, NO₃^?-N, PO₄^3?-P, TSS, and turbidity. The combined hybrid CW showed, therefore, an improved effluent quality with overall removal efficiencies of, respectively, 94% for BOD₅, 88% for COD, 84% for NH₄⁺-N, 89% for NO₃^?-N, 78% for PO₄^3?-P, 85% for TSS, and 97% for turbidity. T. latifolia strived well in the VSSF and HSSF CWs, which may have contributed to the high NH₄ ⁺-N, NO₃^?-N, and PO₄^3?-P removal efficiencies. T. latifolia-planted VSSF CWs showed a higher contaminant removal efficiency compared to the unplanted VSSF CW. T. latifolia is thus a suitable plant species for treatment of secondary refinery wastewater. Also a T. latifolia-planted hybrid CW is a viable alternative for the treatment of secondary refinery wastewater under the prevailing climatic conditions in Nigeria.     

Multivariate correlation of water quality,sediment and benthic bio-community components in Ell-Ren river system,Taiwan

The distribution and correlation of benthic bio-community, water and sediment pollutants were evaluated with multivariate analysis from data collected over six samplings at 12 sites in the Ell-Ren river system, Taiwan. A total of 41 benthic algae species, 8 aquatic insect species and 2 annelid species were collected. On the basis of both principal component and correlation matrix analyses, we defined six water and sediment pollutant components to reveal common behaviour. Metrioenemus sp., Tubifex sp., Bacillariophyceae and Cyanophyceae could tolerate the environment at highly polluted sites. Caenis sp., Rhithrogena sp. and Baetis sp. preferred sites that were aerobic, and their populations were negatively correlated (52–56%) with detrital heavy metals in sediment. The population of benthic algae was positively variated with lead of the “bound to organic matters and sulphides” fraction, but negatively with copper in the detrital pattern. Results suggested that benthic bio-community demonstrated measurable relationships with water and sediment pollutants in Ell-Ren river system, and could be used as indicators to assess the water quality of river over a longer period.     

Community Refinery Wastewater Photodegradation by Fe-Doped TiO<Subscript>2</Subscript> Films

Photocatalytic treatment of real community wastewater using Fe-doped TiO₂ nanofilm was prepared by modified sol-gel method together with a simple dip-coating technique. The process was investigated in a home-made batch photoreactor. The as-prepared nanocomposite film was characterized by UV-Vis diffuse, XRD, BET, and Fe-SEM analysis. The poultry processing wastewater was collected from Nakhonsawan Municipality. Subsequently, the photocatalytic treatment of the wastewater was performed using a home-made photoreactor operated in batch mode to demonstrate the effects of Fe-dopant concentration with various layer numbers. The catalysts were irradiated using four lamps of 15 W power that emitted visible light and performed at room temperature. The samples were collected every 15 min and analyzed for biochemical oxygen demand (BOD) and chemical oxygen demand (COD) removal efficiency compared to pure TiO₂ nanofilm and direct photolysis. From the results, the mixture of rutile and anatase was obtained with the maximum specific surface area of 150.12 mg²/g and the average particle size of 39.95 nm for 3 layers of 0.15% wt/v Fe-doped TiO₂. The BOD and COD value at 90 min time treatment was presented to be 8.87 and 32 mg L^?1, respectively, in the presence of 0.15% wt/v Fe-doped TiO₂ film photocatalysts. Moreover, atomic absorption spectrometric result ensured that no Ti contamination was detected in all parts of plants after watering by the treated water. Hence, the photocatalytic treatment markedly improved the quality of the community wastewater.     

The Efficacy of a Tropical Constructed Wetland for Treating Wastewater During the Dry Season: The Kenyan Experience

Constructed wetlands have recently received considerable attention as low cost and efficient means of cleaning up many different types of wastewaters at secondary and tertiary levels. This is an environmentally sound method of wastewater treatment that does not use hazardous chemicals, and is based on the high productivity and nutrient removal capability of the wetland that strongly relies on its intricate ecosystem structure and function. Research work was conducted on a tropical constructed wetland to establish its capability to treat wastewater during the dry season. A comparison of its efficacy with that of conventional wastewater treatment plants was made on the basis of the measured water quality parameters. Temperature, pH, dissolved oxygen, and conductivity were measured in situ. Total suspended solids (TSS), total dissolved solids (TDS), biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), phosphorus, ammonia, and nitrites were analyzed in the laboratory. Fecal coliforms were enumerated and Escherichia coli counts were determined. The TSS values reduced from a mean of 102 mg/l at the influent point to 16 mg/l at the effluent point, depicting a reduction of 84.3%. Influent TDS averaged 847 mg/l, while the effluent averaged 783 mg/l. Dry season BOD₅ levels were reduced from an average of 286 at the inlet point to 11 mg/l at the outlet representing a reduction efficiency of 96.2%. COD levels were reduced from a mean of 2,002.5 to 47.5 mg/l depicting a removal efficiency of 97.6%. Phosphorus was reduced from a mean of 14 to 11 mg/l representing a percentage removal of 21.4%. Levels of ammonia reduced from a mean of 61 at the influent point to 36 mg/l at the effluent point representing a percent reduction of 41.0%. There was a 99.99% reduction for both the fecal coliforms and E. coli counts. Conductivity of wastewater increased from 1.08 to 1.98 mS, while the pH increased from 6.23 at the inlet point to 7.99 at the outlet of the system. Temperature and dissolved oxygen measurements showed a diurnal variation. The dry season wastewater heavy metal concentrations were in the following ranges: Pb (0.7?C6.9 ppm), Cr (0.2?C0.5 ppm), Zn (0.1?C2.3 ppm), Ni (0.1?C1.3 ppm) with Cd and Cu not being detected in the wastewater streams. Overall, tropical constructed wetlands are effective in treating wastewater streams and they perform a lot better than the popularly used waste stabilization ponds. This paper recommends that they can be widely used within the tropics.     

Comparing the Tolerance Limits of Selected Bacterial and Protozoan Species to Vanadium in Wastewater Systems

This study compared the tolerance limits of selected bacterial (Bacillus licheniformis, Brevibacillus lactosporus and Pseudomonas putida) and protozoan (Aspidisca, Trachelophyllum and Peranema) species to V⁵⁺ in wastewater systems. The isolates were exposed to various concentrations of V⁵⁺ (from 10 to 240?ppm), and their tolerance limits to this heavy metal were assessed at different temperatures (25, 30, 35 and 40°C) and pHs (4, 6, 7, 8 and 10) for 5?days. Chemical oxygen demand (COD), dissolved oxygen (DO) and die-off rate of the isolates were measured using standard methods. The results indicated that test isolates were tolerant to V⁵⁺, with a gradual decrease in their colony/cell counts when V⁵⁺ concentration gradually increased. Bacterial species were found to be more significantly tolerant (MIC: 110?C230?ppm?V⁵⁺) to V⁵⁺ than protozoan species which showed an earlier total inhibition/die-off rate (100%) at 60?C100?ppm?V⁵⁺ (MIC) (p?<?0.001). P. putida was the most tolerant bacterial species (MIC: 230?ppm?V⁵⁺) and Aspidisca sp. the most sensitive protozoan species (MIC: 60?ppm?V⁵⁺). An increase in COD and DO removal was observed throughout the experimental period. The highest COD increase (up to 237.11%) and DO removal (almost 100%) were observed in mixed liquor inoculated with P. putida after exposure to 10?ppm?V⁵⁺. Changes in pH and temperature affected the tolerance limits of all isolates. This study suggests the use of these tolerant bacterial and protozoan species in the bioremediation of V⁵⁺ from domestic and industrial wastewater under the control of pH and temperature.     

Application of stabilization pond for purification of textile wastewater in Esfahan,Iran

Two experimental ponds, with an effective volume of 2 m3 each, were constructed in a workshop at the textile plants to investigate the potential for a stabilization pond for purification of textile wastewater. Parametric analysis of pH, temperature, turbidity suspended solids, total suspended solids, DO, BOD, COD, N, and algae was carried out on the influent and the effluent according to the procedures recommended by the standard methods (APHA, 1971). Considering the results obtained from tests after daily observations, the application of an oxidation pond for treatment of textile wastewaters in the winter time was not promising. The ponds had a little activity in aerobic condition. In other seasons the ponds were efficient and the removal of BOD, COD, and N was 81, 78, 72% respectively, with a loading rate of 7.950 g BOD m^?2 day^?1 and detention time of 20 days. The ponds were usually saturated and sometimes super-saturated with dissolved O₂. The experimental ponds were put to work in series for BOD, COD, and N removal observation. The removal did not improve compared with a single pond and algae concentration was noticeably reduced in the effluent.     

Treatment of Domestic Wastewater by Three Plant Species in Constructed Wetlands

Three common Appalachian plant species (Juncus effusus L., Scirpus validus L., and Typha latifolia L.) were planted into small-scale constructed wetlands receivingprimary treated wastewater. The experimental design includedtwo wetland gravel depths (45 and 60 cm) and five plantingtreatments (each species in monoculture, an equal mixture of the three species, and controls without vegetation), with two replicates per depth × planting combination. Inflow rates (19 L day^-1) and frequency (3 times day^-1) were designed to simulate full-scale constructed wetlands as currently used for domestic wastewater treatmentin West Virginia. Influent wastewater and the effluent from each wetland were sampled monthly for ten physical, chemical and biological parameters, and plant demographic measurements were made. After passing through these trough wetlands, the average of all treatments showed a 70% reduction in total suspended solids (TSS) and biochemical oxygen demand (BOD), 50 to 60% reduction in nitrogen (TKN), ammonia and phosphate, anda reduction of fecal coliforms by three orders of magnitude. Depth of gravel (45 or 60 cm) had little effect on wetland treatment ability, but did influence Typha and Scirpus growth patterns. Gravel alone provided significant wastewater treatment, but vegetation further improved many treatment efficiencies. Typha significantly out-performedJuncus and Scirpus both in growth and in effluent quality improvement. There was also some evidence that the species mixture out-performed species monocultures.Typhawas the superior competitor in mixtures, but a decline in Typha growth with distance from the influent pipe suggested that nutrients became limiting or toxicities may have developed.     

Performance Evaluation of Integrated Constructed Wetlands Treating Domestic Wastewater

The performances of a new and a mature integrated constructed wetland (ICW) system treating domestic wastewater were evaluated for the first time. The new ICW in Glaslough (near Monaghan, Ireland) comprises five wetland cells, and the mature system in Dunhill (near Waterford, Ireland) comprises four cells. The performance assessment for these systems is based on physical and chemical parameters collected for 1 year in Glaslough and 5 years in Dunhill. The removal efficiencies for the former system were relatively good if compared to the international literature: biochemical oxygen demand (BOD, 99.4%), chemical oxygen demand (COD, 97.0%), suspended solids (SS, 99.5%), ammonia nitrogen (99.0%), nitrate nitrogen (93.5%), and molybdate-reactive phosphorus (MRP, 99.2%). However, the mature ICW had removal efficiencies that decreased over time as the Dunhill village expanded rapidly. The mean removal efficiencies were as follows: BOD (95.2%), COD (89.1%), SS (97.2%), ammonia nitrogen (58.2%), nitrate nitrogen (?11.8%), and MRP (34.0%). The findings indicate that ICW are efficient in removing BOD, COD, SS, and ammonia nitrogen from domestic wastewater. Moreover, both ICW systems did not pollute the receiving surface waters and the groundwater.     

Spatio-temporal distribution and characterisation of phytoplankton populations coupled with abiotic and biotic changes in landfill leachate treatment basins (Etuffont, Belfort, France)

The quantitative distribution of dominant phytoplankton species was carried out in the stabilisation ponds of Etueffont landfill leachate (Belfort, France) from May 1998 to May 1999. The results showed maximum phytoplankton abundance in the last lagooning basin during summer 1998, that coincided with an increase in temperature and better leachate quality. In addition, the phytoplankton was dominated by Euglenophytes species Phacus sp. and Euglena sp. known to resist constraints induced by the highly polluted aquatic environments. An improve in water quality of the last basins translated into a shift in species composition with the substitution of the Bacillariophyceae (Stephanodiscus dubius) by the Chlorophyceae (Coelastrum sp.).     

Representation of Particulate Matter COD in Rainfall Runoff from Paved Urban Watersheds

For a half century, total suspended solids (TSS) has been the most commonly utilized particulate matter (PM) gravimetric index for wastewater. While TSS has been extended to urban runoff, runoff phenomena are unique. Runoff is unsteady and transports heterodisperse inorganic granulometry, giving rise to the PM index, suspended sediment concentration (SSC). With respect to PM-associated chemical oxygen demand (COD_p) in runoff, it is hypothesized that, while the TSS method can represent effluent COD_p, the SSC method is required to represent influent COD_p. COD_p and PM indices (TSS and SSC) for runoff events with mass balances and manual sampling are analyzed to investigate this hypothesis. This study examined a series of rainfall-runoff events captured from an instrumented fully paved urban catchment subject to traffic loadings in Baton Rouge, LA. Results indicate TSS generated substantial event-based mass balance errors for COD_p and Δm _p (mg/g) across a hydrodynamic separator (HS) as compared to SSC. TSS underestimates sediment-bound COD (>75 µm), a significant portion (maximum of 63% and median of 50%) of influent load. Negative bias by the TSS method for influent COD_p load increases as the heterodisperse particle size distribution becomes coarser. Above a PM of 250 mg/L, underestimation of COD_p by the TSS method is statistically significant. Utilizing the SSC method, COD_p reduction by a HS upstream of a batch clarifier (BC) indicates that a HS does not provide COD_p reduction, compared to a BC with 60 min of residence time. Representative PM and COD_P assessment suggests frequent BMP and drainage system maintenance to ensure proper operation and reduce pollutant elution.     

Factors Affecting the Growth of Microalgae on Blackwater from Biosolid Dewatering

This paper discusses the possibility of including the culturing of microalgae within a conventional wastewater treatment sequence by growing them on the blackwater (BW) from biosolid dewatering to produce biomass to feed the anaerobic digester. Two photobioreactors were used: a 12 L plexiglas column for indoor, lab-scale tests and a 85 L plexiglas column for outdoor culturing. Microalgae (Chlorella sp. and Scenedesmus sp.) could easily grow on the tested blackwater. The average specific growth rate in indoor and outdoor batch tests was satisfactory, ranging between 0.14 and 0.16 day^?1. During a continuous test performed under outdoor conditions from May to November, in which the off-gas from the combined heat and power unit was used as the CO₂ source, an average biomass production of 50 mgTSS L^?1 day^?1 was obtained. However, statistical analyses confirmed that microalgal growth was affected by environmental conditions (temperature and season) and that it was negatively correlated with the occurrence of nitrification. Finally, the biochemical methane potential of the algal biomass was slightly higher than that from waste sludge (208 mLCH₄ gVS^?1 vs. 190 mLCH₄ gVS^?1).     

Growth promotion of the freshwater microalga Chlorella vulgaris by the nitrogen-fixing,plant growth-promoting bacterium Bacillus pumilus from arid zone soils

Immobilization of Bacillus pumilus ES4 from arid land soils, a plant growth-promoting bacterium and the freshwater, green microalga Chlorella vulgaris enhanced microalgal growth only in the absence of combined nitrogen in synthetic growth medium (SGM), but not in medium with combined nitrogen. B. pumilus was able to fix nitrogen in N-free SGM and its growth yielded an accumulation of ammonium in the medium. On its own, B. pumilus is a poor agent for removing nitrogen and phosphorus from wastewater, while C. vulgaris is a capable microorganism. By jointly immobilizing the two microorganisms, the capacity to remove nitrogen and phosphorus from the medium by the microalgae culture was not enhanced, but, at the cell level, removal of these nutrients was significantly enhanced. It appears that growth promotion induced by B. pumilus on C. vulgaris is related to nitrogen fixation.     

Assessment of Luffa cylindrica as Support in Biofilms Reactors for the Biological Treatment of Domestic Wastewater

A simultaneous treatment of BOD, phosphorous and ammonia in artificial wastewater was carried out in biofilm reactors with Luffa cylíndrica as organic support and compared with PVC's support under variations of dissolved oxygen of 1.5 a 3.0 mg l^?1 in the same reactor. During semicontinous treatment, the removal of BOD (92.5%) with Luffa cilíndrica was higher than PVC support (80%). Nitrification only existed at levels of oxygen of 3 mg l^?1, showed in the effluent a final concentration of ammonium of 17 and 19 mg l^?1 for Luffa cilíndrica and PVC support, respectively. In reactors with Luffa cilíndrica a higher percentage of P removal (40%) was reached, while no elimination in reactors with PVC was observed. The formation of anaerobic-aerobic zones inside the natural support probably allowed the increase in the efficiency of removal of phosphorous. Oxidation of organic matter, P removal and nitrification can be achieved with the variation of oxygen inside of the same biofilm reactor using L. cylindrical as support material.     

Surface Water Quality as Affected by Sugarcane Residue Management Techniques

This study evaluated the impacts of three sugarcane residue management techniques, namely postharvest burning of residue (BR), shredding of residue (SR), and full postharvest retention of residue (RR), on the water quality of surface runoff from February 2006 to September 2007 in Iberia, LA. Total runoff volumes recorded were 58,418, 57,923, and 46,578 L for the BR, SR, and RR treatments, respectively. Except for total Kjeldahl nitrogen (TKN), which was higher for BR than RR or SR, there were no significant differences in total loads of total suspended solids (TSS), total dissolved solids (TDS), biological oxygen demand at 5 days (BOD₅), total phosphorus (TP), nitrate-N, nitrite-N, and sulfate among the three residue management techniques, although the RR treatment generally exported the lowest total loads. Regression analyses on the pollutant load and rainfall event showed that the load exported for each water quality parameter was positively correlated with precipitation, with the BR treatment being more sensitive to rainfall amount than the RR and SR treatments in TSS, TKN, TP, BOD, nitrate, and sulfate exports. Runoff TSS and turbidity were also highly correlated (R ²?=?0.95, P?<?0.001). The results suggested that the two sugarcane residue retention practices (RR and SR) had limited benefit on improving surface runoff water quality over the BR practice in subtropical region such as Louisiana.     

Peat leachmound treatment of residential wastewater in sub-Arctic Alaska

In many areas of the North, conventional septic systems cannot be installed or have failed because of inadequate drainage. Conventional domestic, on-site wastewater may contaminate shallow water tables and surface waters. The effectiveness of two pilot peat leachfields in treating septic wastewater was investigated for approximately two years by comparing the quality of the untreated wastewater collected from the septic system lift stations to the quality of the peat leachate. The quality of the leachate, based on parameters such as BOD, COD, TSS, NO₃-N, TKN, total-P, pH, fecal and total coliform bacteria, color, turbidity, and DO, is similar to wastewater that has undergone tertiary treatment. Temperatures below the leachmound distribution pipes ranged between 1° and 6 °C. Clogging of the interstices with an organic slime was not encountered. The results of the study show that peat leachmounds can be adopted to treat residential wastewater in rural sub-Arctic Alaska and other northern tier countries without compromising ground or surface water quality.