Aerobic Lagoon Research Articles

Evaluation of a Greenhouse Ecosystem to Treat Craft Beverage Wastewater

An aerated greenhouse ecosystem, often referred to as a Living Machine®, is a technology for biological wastewater treatment within a greenhouse structure that uses plants with their roots submerged in the wastewater. This system has a small footprint relative to traditional onsite wastewater treatment systems and constructed wetland, can treat high-strength wastewater, and can provide a high level of treatment to allow for reuse for purposes such as irrigation, toilet flushing, and landscape irrigation. Synthetic and actual craft beverage wastewaters (wastewater from wineries, breweries, and cideries) were examined for their treatability in bench-scale greenhouse ecosystems. The tested wastewater was high strength with chemical oxygen demands (COD) concentrations of 1120 to 15,000 mg/L, total nitrogen (TN) concentrations of 3 to 45 mg/L, and total phosphorus (TP) concentrations of 2.3 to 90 mg/L. The COD, TN, and TP concentrations after treatment ranged from below 125 to 560 mg/L, 1.5 to 15 mg/L, and below 0.25 to 7.8 mg/L, respectively. The results confirm the ability of the aerated greenhouse ecosystem to be a viable treatment system for craft beverage wastewater and it is estimated to require 54 and 26% lower hydraulic retention time than an aerobic lagoon and a low temperature, constructed wetland, respectively, the types of systems that would likely be used for this type of wastewater for onsite locations.

Seasonal behavior of pharmaceuticals and personal care products within Chilean rural WWTPs under COVID-19 pandemic conditions

During the COVID-19 pandemic, the consumption of pharmaceuticals and personal care products (PPCPs) increased exponentially. There is an associated risk concerning the presence of PPCPs from wastewater, mainly in rural zones of emerging countries, where sanitation tends to be poor or inefficient. Therefore, this study aimed to evaluate the seasonal behavior of PPCPs within Chilean rural wastewater treatment plants (WWTPs) under COVID-19 pandemic conditions. Ten Chilean rural WWTPs were monitored during 2021, both in the cold (May–September) and warm (November – December) months, being collected semi-composite samples (influent/effluent). WWTPs were based on activated sludge, aerobic lagoons, rotatory discs, activated sludge + bio discs, constructed wetlands, and vermifilter. Physicochemical parameters and PPCPs (azithromycin, ciprofloxacin, caffeine, ibuprofen, losartan, and triclosan) compounds were monitored. Results showed that PPCPs, such as antibiotics (azithromycin, ciprofloxacin: 14.7 – 100%), stimulants (caffeine: 41.5 – 100%), NSAIDs (ibuprofen: 32.9–100%), β-blockers (losartan: 43.5–100%), and disinfectants (triclosan: 45.9–100%) were variably removed. Non-significant differences (p > 0.05) of the PPPCs (effluent concentrations/efficiencies) were reported regarding seasonality and treatment typologies. Moreover, azithromycin, ciprofloxacin and triclosan reported positive correlations (Ɵ ≈ 0 °) with solids. Finally, this study evidenced that COVID-19 pandemic conditioned seasonally variability of PPCPs from wastewater.

Biosolids processing effect on sulfur plant availability

AbstractUnderstanding the S nutritive value of biosolids produced by various processing methods is important for growers who apply biosolids to crop production fields. Our project goals were to determine how processing method and biosolids’ properties influence S availability and S fertilizer value. Fourteen biosolids materials were selected for the trial, including those produced with aerobic digestion (n = 2), anaerobic digestion (n = 5), dual digestion (n = 1), composting (n = 2), lagoon storage (n = 2), sawdust blending (n = 1), and alkaline stabilization (n = 1). Biosolids were air‐dried, ground, and added to a Walla Walla silt loam soil at a rate of 100 mg S kg–1 soil. The treated soils were incubated at 25 ℃ and extracted for SO4–S on Days 1, 13, 29, 44, and 83. Mean plant available S was greatest for the alkaline stabilized biosolids (52%), followed by anaerobically digested biosolids (40%), sawdust blended biosolids (37%), lagoon slurry (36%), dual digestion biosolids (31%), aerobically digested biosolids (15%), and composted biosolids (4%). Biosolids pH, organic C/total S, total Ca, total S, and SO4–S concentrations were well correlated to S release rate, plant available S, or both. Sulfur mineralization of organic S compounds is known to be influenced by organic C/total S, whereas Ca and pH effects may be related to gypsum (CaSO4) dissolution and oxidation of hydrogen sulfide compounds. The correlations discussed here may need to be further investigated and verified on additional soil types and under field conditions prior to grower adoption.

Nutrient use efficiencies, losses, and abatement strategies for peri-urban dairy production systems

Manure management is an important aspect of urban livestock production that has a profound impact on metropolitan living. Data were collected from 28 dairy farms in peri-urban Beijing and analysed to determine farm nitrogen and phosphorus flows and costs associated with various manure management options to reduce nutrient losses. Dairy production in peri-urban Beijing was characterized by its use of high protein diets (16.3–17.0% crude protein), high reliance on imported feeds (92–98%), and low manure recycling (3.0–10.8%). Farms of 900–2000 cattle showed lower use efficiencies than farms of <900 cattle. Costs of manure handling ranged from 0.1 to 1.0 Yuan kg−1 milk. Among various manure treatment options, biogas digesters with aerobic lagoons had the lowest N losses and costs, justifying their investments. In conclusion, peri-urban dairy production systems were contrasting with traditional systems and within their own systems in nutrient use efficiency and losses, which was mainly decided by their farm size. To improve the nutrient use efficiencies and reduce losses, farmers and managers of peri-urban dairy production system should have a full awareness of different feed intake and manure management.

Estudio piloto para el tratamiento de lixiviados generados en un botadero controlado

El objetivo del estudio fue evaluar la eficiencia de una laguna de estabilización aerobia piloto anexa al tratamiento primario existente para los lixiviados producidos en un botadero controlado ubicado en la Provincia de Pichincha-Ecuador. Se caracterizó el lixiviado a la entrada y salida del sistema cada 14 días por un tiempo de retención de 51 días por dos periodos. El lixiviado que alimento la laguna alcanzó una concentración máxima de DBO5 de 722 mg L-1 y DQO de 1338 mg L-1. Luego del tratamiento, el lixiviado redujo la DBO5 a 9 mg L-1 y DQO a 91 mg L-1 para el primer periodo de muestreo y 62 mg L-1 de DBO5 y 294 mg L-1 de DQO para el segundo periodo, es decir, una eficiencia de remoción en función de DQO fue del 91,17% y 98,24% de DBO5. Además, la remoción de coliformes fecales fue de 99,99%. Adicionalmente, se examinaron varios parámetros físico-químicos para analizar el aporte a la calidad del lixiviado. Con los datos de concentración de materia orgánica y aforo del lixiviado se determinó los parámetros de diseño del tratamiento biológico anexo al tratamiento primario existente.

PENGOLAHAN DAN PEMANFAATAN AIR LIMBAH INDUSTRI BIODIESEL

As a tropical country, the availability of biomass is very abundant in Indonesia. Biomass is a source for renewable energy. One of the renewable energy is biodiesel. Biodiesel is produced by trans-esterifi cation of oil/fat. During the process, biodiesel industry produces either wastewater and/or solid waste. The wastes should be treated carefully. The wastes from biodiesel industry are categorized as organic wastes. Therefore, the treatment and utilization of such wastes is done biologically. The wastewater will be treated through in series of anaerobic, aerobic process and artifi cial wetland. Gas resulted from the stripping process in aerobic lagoon will be treated by using biofi lter. The solid waste will be utilized for producing compost by wind row composting. Wastewater from biodiesel industry contains high organic matter. The Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD) are 21.300 mg/L and 6.300 mg/L. Therefore, during treatment the process should be carefully handled. The quality of treated wastewater will be improved by treating it in an artifi cial wetland. When the treated wastewater has a positive impact towards the plant growth in the artifi cial wetland, then the treated wastewater will be utilized for liquid fertilizer by adding the macro and micro nutrient such as N, P, K, Ca, Mg, Mn, Co,Mo, S, and so forth. The prototype of wastewater treatment facility has been built in PUSPIPTEK Serpong with the capacity of 2.5 m3 of wastewater/day. The anaerobic process is established in an anaerobic digester (fi xed bed). The bed used is made of plastic. The aerobic digester is an activated sludge. Therefore, side products from this activity are biogas, compost and liquid fertilizer.Key words: fixed bed digester, activated sludge, biofi lter, compost, artifi cial wetland.

PERANCANGAN PENGOLAH LIMBAH CAIR KOMBINASI PROSES KONTAK DAN AEROBIC LAGOON DENGAN MENGGUNAKAN VISUAL BASIC 6

Application of computer programming is cheaper and faster method to design waste water treatment reactor. The aim of the program are to calculate dimension of unit operation of waste water treatment type contact process, aerobic lagoon and sedimentation pond and to count BOD output from waste water treatment and arrange of unit operation. It uses Computer Language Visual Basic 6.Key words: Contact Proses, Aerated Lagoon, dimension, BOD, computer programming

Simulating the effects of mesophilic anaerobic and aerobic digestions, lagoon system, and composting on pathogen inactivation

To improve understanding of pathogen inactivation in flushed dairy manure during anaerobic digestion, lagoon systems, and mesophilic composting, we assessed pathogen inactivation in batch-scale anaerobic digesters, aerobic lagoons, and manure piles. Further, we assessed the impact of air injection in lagoon systems on pathogen inactivation. The inactivation of Salmonella and E. coli was studied for more than 70days. The change in pH, total solids, total carbon, and total nitrogen during manure treatment was determined. The results showed that the lagoon system with air injection to be more effective in pathogen removal compared to the lagoon system with no air injection, anaerobic digestion, and mesophilic composting. Both types of lagoon systems (with and without air injection) were found to be more effective in eliminating pathogens than anaerobic digester systems. Mesophilic manure pile extended the survival of both Salmonella and E. coli. In the anaerobic system, E. coli was detected beyond 60days of incubation, while in the aerobic system; it was eliminated in 30–35days. In anaerobic system, Salmonella reached to non-detectable level in 30–35days, while in aerobic system it took 4–12days. In the mesophilic manure pile, however, E. coli survival was extended beyond 78days. Less than one log reduction was obtained in 78days of mesophilic composting. Salmonella survival was also extended in mesophilic composting pile.

Operation and Performance of a Farm-Scale Anaerobic Sequencing Batch Reactor Treating Dilute Swine Manure

Abstract. A 400 m3 anaerobic sequencing batch reactor (ASBR) treating dilute (0.30% to 1.0% total solids) swine manure produced by a 120-sow farrow-to-finish farm was monitored for one calendar year. The digester was operated at full reactor volume (20-day hydraulic retention time, HRT) and at conditions considered optimal for biogas production (5-day HRT). Reactor temperature during 20-day HRT operation ranged between 22°C and 32°C, and solids retention time (SRT) averaged 51 days. During 5-day HRT operation, reactor temperature was 22°C to 24°C and SRT averaged 26 days. Organic matter removal efficiency, measured as the difference between daily mass of chemical oxygen demand (COD) entering the reactor and COD leaving with decanted liquids, was 73% during 20-day HRT operation and 57% during 5-day HRT operation. Methane yield was 0.55 m3 CH4 kg-1 volatile solids (VS) during 20-day HRT and 0.38 m3 CH4 kg-1 VS during 5-day operation. In general, organic matter removal was lower and methane yield was higher than results using similar manure in laboratory-scale reactors. Volumetric reactor efficiency (VRE) was 0.18 m3 CH4 m-3 reactor d-1 under both operating conditions. Flushed manure was diluted 30:70 with recycled aerobic lagoon effluent to provide sufficient volume to achieve 5-day HRT operation. The VRE of an ASBR treating flushed manure without lagoon effluent dilution at 5-day HRT was estimated to be greater than 0.70 m3 CH4 m-3 reactor d-1 based on microbial kinetic models.

English

A pilot biochemical reactor (BCR) with a design flowrate of 3.8 l/m (1 gpm) has been operating at the Standard Mine Superfund Site for over four years, since August, 2007. The pilot system is entirely passive, using solar energy to power sampling equipment and pumping requirements. BCR treatment relies on biological and chemical reactions within an anaerobic reactor comprised of organic and inorganic materials including woodchips, straw, limestone and bacterial inoculum. The BCR pilot has been treating mining influenced wastewater (MIW) since construction was completed in the summer of 2007. Polishing and aeration of BCR effluent is accomplished in an aerobic polishing cell (APC) containing wetland plants in two of the three cells. The Standard Mine BCR is constructed at an elevation of 3,353 meters (11,000 ft ) above MSL with an average annual snowfall of 10.2 m (400 in ). Limited BCR treatment data from reactors operating under harsh alpine conditions was available before this system was constructed. Operation and monitoring of the BCR has been year round since 2007. Due to the inaccessibility of the site during winter months, an automated sampling system was designed incorporating Teledyne ISCO™ (ISCO) samplers, Hydrolab™ sondes, and a satellite transmission system reporting site operational parameters on a daily basis. In addition to automated sampling, grab samples were taken monthly throughout the 2010/2011 winter using backcountry skiing equipment to access the site. Contaminants of concern (COCs) in the MIW include Cd, Cu, Pb, Mn, and Zn. High metals removal has been observed in BCR effluent since the beginning of operation. In 2009, 2010, and 2011 the average percent removal efficiency for cadmium, Cu, Pb, and Zn exceeded 98%. The pilot study is notable for a long operating period and low analytical laboratory detection limits for metals. BCR treatment of cadmium, Cu, and Pb to less than 5 µg/L has been demonstrated indicating that BCR is capable of approaching or meeting stringent aquatic life water quality standards when operated under harsh high alpine conditions. Both metals and nutrient removal are discussed in relation to receiving stream water quality standards. BCR performance is discussed with additional discussion of performance of BCR effluent polishing by aerobic lagoon.

Full-scale trials of external nitrification on plastic media nitrifying trickling filter

The full-scale single-stage tertiary nitrifying trickling filter (NTF) at the Citrusdal Wastewater Treatment Plant provides for external nitrification of unclarified effluent from the facultative aerobic lagoon in order to meet standard effluent ammonia concentration requirements. The apparent ammonia nitrification rate (ApANR, gN/m2 media surface·d) of the NTF was sensitive to particulate organic loading rates which were predominantly in the form of algae, and the soluble COD removal rates increased under cold climates. Installation of forced-air ventilation fans improved the nitrification efficiency from 15% to 43%. An increase in hydraulic loading rate (HLR) by effluent recirculation significantly improved the ApANR, eradicated filter flies and decreased the prevalence of worms. Maximum ApANR of ~1.0 gN/m2·d was achieved yielding an ammonia- removal efficiency of approximately 71%. Profile samples collected along the NTF media depth indicated poor media wetting at low HLR resulting in low ApANR (<0.5 gN/m2·d). Also during the cold and rainy winter period, poor biofilm activity and prevalence of motile algae were observed, and under low hydraulic loading rates and warmer temperatures, a dominance of filter flies and fly larvae were observed. In contrast, in controlled laboratory studies, ApANRs up to 1.72 gN/m2·d (22.1 mgN/l removal) were attained, which, in conformity with full-scale, was also found to be sensitive to hydraulic loading conditions.

Quantitative bacteriological assessment of aerobic wastewater treatment quality and plant performance

The application of a novel method for measuring changes in defined bacterial populations during aerobic wastewater treatment was investigated. Changes in bacterial communities and total active cells can be used as surrogates for identifying potential WWTP treatment train efficiency and operational performance malfunctions. In this study, the quantities of active heterotrophic aerobic bacteria (HAB) in weekly wastewater samples collected from twelve locations across a WWTP were determined colorimetrically using biological activity reaction tests (BART). Samples were collected for 2 months from primary, secondary and tertiary unit processes. The results show a mean HAB population decrease of 99.8% from primary influent to tertiary effluent, with the largest reductions occurring in the secondary aerobic lagoons. The results were reproducible and robust supporting the applied BART analytical method as an indicator not only of overall efficacy of the WWTP processes but also of potential WWTP process malfunctions.

Characterization and analysis of medical solid waste in Osun State, Nigeria

This paper reports the study of quantum and characterization of medica solid wastes generated by healthcare facilities in Osun State. The work involved administration of a questionnaire and detailed studies conducted on facilities selected on the basis of a combination of purposive and random sampling methods. The results show that the facilities are well spread among the 30 Local Government Areas; that the total quantity of medical waste generated in the state is 2672 kg/day and when domestic wastes are included the total is 5832 kg/day; that the medical wastes are not being properly disposed of as pathology wastes such as unclaimed dead bodies, placentas, umbilical cords are being dumped into unlined pits and other wastes in open dumps. A centralised system is proposed state–wide involving use of incinerators, landfills, aerobic lagoons, and reed beds. The Federal Ministry of Environment has responsibility to push for development of legislation and codes of practice that would guide facilities to achieve waste segregation, packaging in colour-coded and labeled bags, safe transportation and disposal of medical waste. Keywords : Medical solid wastes, pathological wastes, incinerators, landfills, aerobic lagoons, reed beds.

Assessment of treatment capabilities of Varthur Lake, Bangalore, India

Manmade waterbodies have traditionally been used for domestic and irrigation purposes. Unplanned urbanisation and ad-hoc approaches have led to these waterbodies receiving untreated sewage. This enriches and eutrophies the waterbody. A physico-chemical and biological analysis of sewage-fed Varthur Lake in Bangalore was carried out and its treatment capabilities in terms of BOD removal, nutrient assimilation and self-remediation were assessed. Anaerobic conditions (0 mg/L) prevail at the inlet which improves towards the outlets due to algal aeration. This removed >50% BOD in the monsoon season but was inhibited by floating macrophytes in all other seasons. Alkalinity, TDS, conductivity and hardness values were higher when compared to earlier studies. This study shows the lake behaves as an anaerobic∼aerobic lagoon with a residence time of 4.8 d treating the wastewater to a considerable extent. Further research is required to optimise the system performance.

Design and Evaluation of a Sequential Biological Treatment System for Dairy Parlor Wastewater in Southeastern Louisiana

Milking center wastewater from Louisiana grazing dairy operations is a prime candidate for biological treatments. The objective of this study was to evaluate the design and treatment performance of a replicated multiple stage treatment system. Each Dairy Wastewater Treatment Evaluation System (DWTES) replicate is composed of one anaerobic/facultative lagoon (ANL), one aerobic lagoon (AEL), and three constructed wetlands (WLD) placed in sequence. Two WLD (one in each replicate) were planted (PWLD) with pickerelweed (Pontederia cordata) and compared with WLD containing voluntarily grown vegetation/algae (CWLD). Approximately 23,000 L of untreated dairy waste and wash-water was pumped twice daily during milking times. Water quality monitoring began 1 June 2005 and ended 31 May 2006. Sampling was conducted at 0700 h bi-weekly at the terminal end in all stages. Among 20 water quality characteristics studied, efficiency of contaminant removal was highest (removal rates =67%) for COD, TSS, TKN, NH3-N, SO4, and log of ECC. Relatively low TKN concentration in raw wastewater (110 mg/L) resulted in removal rates higher than 85% in the system's effluent. Escherichia coli count was reduced by 4.5 orders of magnitude from 6.65 log MPN/100 mL at the inlet. Sequential anaerobic-aerobic-wetland wastewater treatment design could be a viable alternative for dairy wastewater contaminant abatement in Louisiana if legislation requires further treatment or if a farmer intends to reduce the amount/concentration of nutrients and/or contaminants that need to be recycled within the dairy operation.

Sources and build up of Zn, Cd, Cr and Pb in the sludge of Gaza

A comprehensive monitoring program was conducted for the sludge of Gaza between 2001 and 2006. All 32 tested parameters except zinc and adsorbable organic halogens were within the allowable values for sludge to be applied in agriculture. Average concentrations of zinc (Zn) in the sludge from the Gaza Strip for the 4 years 2002-2005 reached 2,000 mg/kg which represents a major limiting factor for sludge application in agriculture. This study aimed to measure levels of Zn in the wastewater and sludge in December 2006 and to identify the sources and the build up of Zn in the sludge in Gaza. Cd, Cr and Pb were also assessed for their relationship to sources and buildup of Zn. The results showed that there is no significant fluctuation in the concentration of Cd, Cr and Pb in the different stages of wastewater treatment. Zn, however, is concentrated inside the treatment plant by processes of precipitation and/or absorption, particularly in the aerobic facilities. Although the plant receives wastewater with Zn concentrations of only 9 microg/l, this concentration increased 18-fold inside the aerobic lagoon of the treatment plant, before dropping to an average of 14 microg/l in the effluent wastewater. The sludge from the first sedimentation pond showed a Zn concentration of 567 mg/kg and increased in the effluent polishing pond to 1,643 mg/kg. The Zn concentration in 3-month-old sludge averaged 592 mg/kg. There was no correlation between the Zn concentrations in the sludge and the wastewater at the same location. However, there was a strong correlation between Zn and Pb in the sludge. The electroplating and galvanization industries are the major Zn producing industries in Gaza, with an average Zn of 2,995 and 1,557 microg/l, respectively in their effluent wastewater. These values do not represent a significant Zn pollution load to the treatment plant because these industries are limited in size and number, and their effluents are diluted before entering the treatment plant. Industrial activity decreased in 2006 to less than 70% of that in the previous four years. Consequently, the average concentrations of Zn in selected industrial effluents decreased from 1,500 for 2002-2005 to 400 microg/l in December 2006. Sludge from these industries showed 1,300 mg/kg Zn for 2002-2005 and only 400 mg/kg in 2006. Moreover, the Zn in the influent wastewater discharged to the treatment plant decreased from 65 to 9 microg/l for the same period. Exposure of sludge to the sun for few months reduces the Zn concentration. One reason is probably leaching. This simple procedure may solve the problem of sludge application in agriculture. This will be especially important if industrial production returns to its former level.

Fate of estrogens and xenoestrogens in four sewage treatment plants with different technologies

The fate and removal of the estrogens 17beta-estradiol (E(2)), estrone (E(1)), and 17alpha-ethynylestradiol (EE(2)) and of the xenoestrogens bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), 4-nonylphenol (4-NP), and nonylphenol mono- and diethoxylate (NPEO1 and NPEO2, respectively) were investigated in four South Australian sewage treatment plants (STPs; plants A-D) with different treatment technologies. The concentrations in the effluent from the two-year survey were similar to those reported in other studies. In the effluent, 4-NP, NPEO1, and NPEO2 had total concentrations up to 8 microg/L, which were much higher than those of BPA and 4-t-OP. Estrone had the highest concentrations among the three estrogens, ranging between 13.3 and 39.3 ng/L, whereas the concentrations for E(2) and EE(2) varied between 1.0 and 4.2 ng/L and between 0.1 and 1.3 ng/L, respectively. The removal rates for the estrogens and xenoestrogens were variable but consistent with the plant performance parameters (biochemical oxygen demand, suspended solids, and ammonia). Considering all the estrogenic compounds analyzed in the present study, plant D, with a series of anaerobic and aerobic lagoons, was the least efficient of the four STPs in the removal of these compounds. The removal rates for 4-NP, NPEO1, and NPEO2 within the plants were 92% for plant A, with conventional activated sludge treatment; 80% for plant B, with two oxidation ditches; 70% for plant C, with three bioreactors; and 64% for plant D, with 10 lagoons in series. Comparatively, the removal of estrogens was lower, with rates ranging between 47 and 68% for E(2) at the four plants. Both E(1) and EE(2) were more persistent during treatment, especially in plants C and D.

Case Study: Odour Risk Management at the Western Treatment Plant, one of Australia's Largest and Most Unique Wastewater Treatment Plants

Case Study: Odour Risk Management at the Western Treatment Plant, one of Australia's Largest and Most Unique Wastewater Treatment PlantsThe Western Treatment Plant (WTP) is one of Australia's largest and most unique wastewater treatment plants (WWTP) treating over 52% of Melbourne's sewage in a process consisting of open carriers, covered anaerobic lagoons, aerobic lagoons and activated sludge treatment. Large lagoons are also used for the storage and processing of dewatered waste activated sludge from a number of Barwon Water...Author(s)Josef CescaMethew CunningtonSourceProceedings of the Water Environment FederationSubjectSession 1: Methods of Sampling, Measuring, and Estimating Emissions IDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2008ISSN1938-6478SICI1938-6478(20080101)2008:4L.1;1-DOI10.2175/193864708788807853Volume / Issue2008 / 4Content sourceOdors and Air Pollutants ConferenceFirst / last page(s)1 - 15Copyright2008Word count476

Size-fractionation and characterization of refuse landfill leachate by sequential filtration using membranes with varied porosity

Fresh leachate and effluents samples were collected from the holding tank, anaerobic, anoxic, and aerobic lagoons at Shanghai Laogang Refuse Landfill, the largest landfill in China with a placement scale of 9000 t refuse per day. To characterize the difference in leachate along the treatment processes, especially the information about size distribution of colloids in those leachate, the organic matters were size-fractioned into suspended particles (SP, >1.2 μm), coarse colloids (CC, 1.2–0.45 μm), fine colloids (FC, 0.45 μm to 1 kDa MW, 1 Da = 1/16 O atomic mass unit), and dissolved organic matters (DM, <1 kDa MW) using micro-filtration and ultra-filtration membranes in order. The parameters, such as COD (chemical oxygen demand), TOC (total organic carbon), TS (total solid), pH, TP (total phosphate), TN (total nitrogen), FS (fixed solid), NH 4 +, IC (inorganic carbon), TC (total carbon), color, turbidity and conductivity in the filtrates resulting from sequential filtration of leachate, were then determined, and quantitative relationships between these parameters and the membrane molecular sizes used were established. Typically, the total removal of COD, NH 4 +, conductivity and P were found to be 75%, 75%, 42% and 85%, respectively, after the biological treatment processes used at Laogang Refuse Landfill. Dissolved fractions were predominant in fresh leachate and in effluents from treatment processes in terms of TOC with a content of over 47%. The molecular weight (MW) percentage distribution in leachate varied as the leachate was treated in the biological treatment stages. The percentages of TOC of fine colloid fractions increased from 6% to 38% while those of dissolved fractions decreased from 78% to 47%. TN in leachate also predominated in the dissolved fraction, occupying over 58%, while those TP in leachate were combined with the SS and CC fractions. The ratios of ortho-phosphate/TP and NH 4 +/TN in leachate and effluents were over 50% and 80%, respectively.

Improved aerobic biodegradation of abietic acid in ECF bleached kraft mill effluent due to biomass adaptation

Kraft pulp mill effluents contain elevated concentrations of resin acids, chiefly abietic and dehydroabietic acid, and other lipophilic wood constituents. Resin acids, if not efficiently removed during wastewater treatment, can be responsible for chronic toxicity in aquatic systems. The objective of this study was to investigate the biological removal of abietic acid (AbA) during the treatment of elemental chlorine free (ECF) kraft mill effluents in aerobic lagoons and to assess its improvement with time as a result of biomass adaptation. Under these conditions, the average removal efficiencies of AbA and BOD 5 attained in the aerobic lagoon were high and exceeded 80% and 95%, respectively. Microbial inhibition of non-acclimated and acclimated biomass by AbA was not detected in batch bioassays. Kinetic studies showed that the K s and V m values equalled 76.7 mg AbA/l and 0.011 l/h, respectively, for the non-acclimated biomass, and 1678 mg AbA/l and 0.13 l/h, respectively, for the acclimated biomass.