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Domestic wastewaters have a significant concentration of nutrients that can be utilised as alternative sources of phosphorus and nitrogen for agriculture applications. Chemical precipitation is one of the processes found to be an efficient way for nutrient recovery from various wastewater feedstock. However, not all nutrients are in a form that can be readily recovered. Therefore, a pre-treatment process may be necessary for an efficient recovery of nitrogen and phosphorus. In this research, acid hydrolysis was performed as pre-treatment to release phosphorus from synthetic septage into soluble forms for the subsequent precipitation as struvite (MgNH4PO4·6H2O) which is known as a slow-release fertiliser for application in agriculture. Results show that acid hydrolysis increases the phosphate concentration (PO4-P) to 148.07 ± 1.78 from 61.50 ± 0.07 mg/L, showing the potential of hydrolysis as pre-treatment to efficiently recover nutrients in the form of struvite. The result can inform further research to develop efficient processes for the recovery of nutrients from domestic wastewater. [ABSTRACT FROM AUTHOR]

Comprehensive and proper management of fecal sludge (FS) is an ongoing concern in many nations. Decentralized fecal sludge treatment plants (FSTPs) are effective in this regard; however, many have experienced strong public opposition based partly on suspicion of malodor. Fecal sludge and freshly generated fecal matter (FM) samples from various FSTPs were collected, characterized, and investigated for biomethane potential. The homogenized samples were anaerobically digested for 28 days. Digestion successfully reduced total suspended solids, biochemical oxygen demand, and threshold odor number values of 97,350–97,420 mg/l, 43,230–43,260 mg/l, and 130–150 for FM, to 49,500–49,650 mg/l, 23,760–23,850 mg/l, and 3338, respectively, for FS samples. The comprehensive gas yield from Bhongir, Boduppal, and Shadnagar FS samples was 40, 55, and 31 ml, respectively. In contrast, cumulative gas generation from the FM was 26,361 ml. Digestion of FS samples also reduced concentrations of volatile solids and coliforms by 66–72% and 99%, respectively. Characterization of gas samples revealed methane and carbon dioxide concentrations as 56% and 22% for FM, and 0.4% and 61% for FS samples, respectively. Hydrogen sulfide and ammonia gas were absent in FS samples, dispelling common societal misconceptions of FSTPs being associated with malodor. [ABSTRACT FROM AUTHOR]

Contaminants of Emerging Concern (CEC) are gaining attention as they continue to attract public awareness and more environmental and health consequences are recognized. This study showcases CEC concentrations within Minnesota's Subsurface Sewage Treatment Systems (SSTS). The study identifies a broad range of CECs associated with subsurface sewage treatment at four sites. Three sites are Minnesota Department of Transportation rest area SSTS with high user inputs, and one site is a septage land application field that receives septage from residential and septic commercial tanks. The studied CEC include antibiotics, chronic disease prescriptions, veterinary medicine, stimulants, hormones, antihistamines, pain and fever relief prescriptions, and a plasticizer. CEC were quantified in the septage, septic tank effluent, advanced treatment effluent, soil, and shallow groundwater. The samples were analyzed via mass spectrometry coupled with light chromatography, revealing that CEC concentrations decrease as they move through the SSTS system. Septage had the highest concentrations of CEC, followed by septic tank effluent. Groundwater had the third highest concentrations, and soils had the lowest concentrations of CEC. CEC concentrations are being reduced through SSTS, but some persist in shallow groundwater. [ABSTRACT FROM AUTHOR]

A lab based hybrid constructed wetland system (1.645 m2) consisting of sludge drying bed (0.135 m2), vertical sub-surface flow bed (0.58 m2), and horizontal sub-surface flow bed (0.93 m2) was operated for the treatment of septage. All the beds were filled with gravels of varied sizes (5-40 mm), sand (0.25 mm) and planted with Canna indica L. Average concentration in influent and effluent was observed as; BOD5 (2395.6±1196.4 and 41.87±8.9 mg/L), COD (7442± 7342.6 and 29.6±7.6 mg/L), TSS (4965.9±801.69 and 336.1±152.9 mg/L), TN (1774.8±693.5 and 55.7±13.7 mg/L), and Total P (849.3±237.7 and 7.05±3.5mg/L) during study period. Hybrid System was operated with high influent loads of BOD5 (175.2± 87.5 g m-2 d-1), COD (544.5±537 g m-2 d-1), TSS (363.3±58.6 g m-2 d-1), Total N (129.8±50.7 g m-2 d-1), NH4-N (7.8±1.1 g m-2 d-1), and Total P (62.1±17.4 g m-2 d-1), throughout the study period. Hybrid-CW has showed significant removal of BOD5 (99.1±0.3%), COD (99.7±0.3%), TS (98.2±6.8%), TSS (96.9±4.9%), Total N (98.4±0.4 %), NH4-N (94.8±0.1%), and Total P (99.6±0.1%) from the septage. Finally treated septage met effluent discharge standards for all parameters except BOD5.

The decentralized standalone treatment of faecal sludge is a generally cumbersome, energy-intensive, and expensive process. Particle size enlargement, dewatering, and disinfection are the crucial unit operations that contribute to the major portion of the operational expenditure. Therefore, the present study took up the task to investigate and yield a natural alternative to each of the above-delineated unit operations. Crushed seed powders of Moringa, Guilandina bonduc, Nirmali, tamarind, soap nut, nutmeg, jackfruit, and custard apple were experimented as natural coagulants, while a double-stitched cow dung–lined jute tube was utilized as the media for solid-liquid separation. Finally, the powder of Neem and custard apple seed and leaf were considered herbal disinfectants for the separated liquid and solid fractions, respectively. The findings of the physicochemical and biological analyses of the above unit operations were compared with a conventional polymer–based Geotube-driven treatment scheme. The natural alternatives registered some promising outcomes. However, the combined treatment efficiency of 79.32% (mean value of TS, TSS, TDS, COD, and BOD percentage removal) for pollutant removal and disinfection could not exceed the value of 97.98% offered by the conventional method. Further, the financial comparison for processing a 10 KL batch of FS indicates that the conventional scheme is considerably cheaper (USD 7.95) than the herbal alternate (USD 22.1). Therefore, though the present findings depict promising alternatives for sustainable and eco-friendly faecal sludge treatment, the authors advocate conducting further research to address the existing challenges to facilitate their seamless implementation on a field-scale level. [ABSTRACT FROM AUTHOR]

Nutrient recovery technologies have been constantly developed and optimised to address challenges in water and wastewater management, sanitation, and agri-food systems, while promoting sustainable management of resources and circular phosphorous economy. However, these technologies have been rarely explored beyond the laboratory-scale in developing countries where it is mostly needed. In this study, a nutrient recovery batch reactor system was installed at a local farm in the Philippines to process raw septage from an onsite sanitation system, a septic tank, to recover a high-value fertiliser for local crop production. The batch reactor was used for two processes, namely acid hydrolysis for pre-treatment of septage and chemical precipitation for recovered phosphorous fertiliser (RPF). The recovered fertiliser was then applied to produce eggplants and tomatoes, which are the common crops grown in the farm. Results show that an average of 290 g of RPF was produced for every 100 L of raw septage processed. With hydrolysis, 77% of the phosphate concentration were released as phosphates from the solid component of the raw septage. About 98.5% of phosphates were recovered from the hydrolysed septage. The RPF when applied to the farm's eggplants and tomatoes has yields comparable to that of the commercial fertilisers. This study was able to demonstrate the potential of a resource-oriented sanitation system that promotes nutrient recycling towards sustainable agriculture that further leads to meeting the United Nations sustainable development goals, particularly zero hunger (goal 2), clean water and sanitation (goal 6), sustainable cities and communities (goal 11), and responsible consumption and production (goal 12). [ABSTRACT FROM AUTHOR]

Septage, which is made up of liquid and solid materials pumped from septic tanks, can be a potential co-digestion resource for sewage sludge. This study was conducted to evaluate possibility of co-digestion of sewage sludge and septage. Biochemical methane potential tests were performed using primary sludge, secondary sludge and septage. The mixing ratio of the septage ranged from 30% to 62% (by volatile solid wt.) based on the typical ratio of the septage transported to municipal WWTP plants and the sewage sludge generated in the plants. The co-digestion of sewage sludge and septage showed synergistic effects on the methane potential due to the enhanced C/N ratio. The observed methane potential of co-digestion substrate was 8–16% higher than the predicted value based on weighted average of mono-digestion substrate's methane potentials. The maximum synergistic effect on methane potential was observed when 42% (by volatile solid wt.) of the septage was co-digested. In conclusion, the septage can be a suitable resource for co-digestion with sewage sludge. [ABSTRACT FROM AUTHOR]

Achieving effective, city-wide inclusive sanitation service delivery requires coordination of diverse actors in the sanitation value chain as many factors constrain the efficiency and quality of faecal sludge management (FSM). In partnership with government, consumer, and private sector stakeholders in Bihar's capital city, Patna, PSI India facilitated extensive market analysis, identified the market challenges, and co-developed a market-based urban FSM services 'ecosystem' which resulted in the safe collection, treatment, and disposal of over 7 million litres of faecal sludge from more than an estimated 1,500 households over two years, as part of bundled portable toilet cabins and FSM services. The FSM programme Praashadan, funded by the Bill & Melinda Gates Foundation, built trust, improved coordination, and brokered official agreements between tanker operators and government, tested a portable toilet cabin business model to subsidize operation of a faecal sludge treatment plant, and established a call centre and promotional activities to drive customers to the services of a newly formed tanker operators association. Moving forward there is a need to place the work with these market actors into a wider context of a financed, coordinated, city-wide sanitation planning to address technology, R&D, and other constraints that support better business models and allow regular quality FSM services. [ABSTRACT FROM AUTHOR]

Greenhouse gas emission during composting process is inevitable, although it relies on natural degradation. A good balance on carbon-to-nitrogen (C/N) ratio as well as the aeration mode could significantly control the emissions. The C/N ratio can be adjusted using optimal feedstock composition. The aeration can be done using passive and active modes. In the present study, greenhouse gas emissions during in-vessel co-composting of septage and organic waste with active and passive modes of aeration were investigated. This fills the gap in implementing suitable septage treatment practice. Retention of high temperature (> 55 °C) for prolonged period ensured the compost hygienization. The active aeration system showed significantly lower greenhouse gas emission compared to that of passive system. The contribution of CH4 and N2O to the total greenhouse gas was estimated to be 2.5% and 7.4% in the passive and 0.9% and 3.8% in the active aeration modes while > 90% was CO2. The resulted compost maturity was confirmed by seed germination index (> 80%) and NO3−/NH4+ index (> 6.25). Our study highlight that in-vessel co-composting with active aeration is a suitable option to convert waste to a nutrient-rich fertilizer in a shorter period compared to other septage treatment options. [ABSTRACT FROM AUTHOR]

Anaerobic fermentation inside the digestor is the continuous process which results in the formation of useful biogas fuel. All feedstocks are not easily decomposable thereby necessitating the design of an “optional in-line pre-digestor assembly”. Initially a 2 m3 modified fixed dome ‘Deenbandhu’ type biogas plant was commissioned with cattle dung, bypassing the pre-digestor assembly. In a phased manner, cattle dung was substituted with poultry litter as feedstock. Gradually increasing the substitution @ of 10% per fortnight, complete substitution of cattle dung could be attained in 18 week time. Poultry droppings assorted with paddy husk from deep litter system of poultry housings were used as feedstock. As paddy husk were indecomposable inside the digestor, an in-line pre-digestor assembly was used to remove the unwanted paddy husk by water dissolution technique. Enzymatic hydrolysis initiated in the pre-digestion tank in the 24 hours residence time improved the digestibility of the feedstock for generating biogas. The process of cattle dung substitution with poultry litter was complete in 18 weeks duration. Daily gas production was recorded with the help of wet type gas flow meter. The gas produced was continuously used for domestic cooking. The total solid (TS) content of the poultry litter based feedstock slurry was maintained at around the same TS (9 - 10%) as that of cattle dung (dung to water at 1:1 ratio) slurry. With 100% use of poultry droppings at 10.3 % TS, average gas production level was 208.5 lit per kg of TS.

A pilot scale study was conducted on a down-flow hanging sponge (DHS) reactor installed at a sewage treatment plant in Banda Aceh, Indonesia for treatment of desludging septic tank wastewater. Raw wastewater with an average biochemical oxygen demand (BOD) and total suspended solids of 139 mg/L and 191 mg/L, respectively, was pumped into the reactor. Two different hydraulic retention times (HRTs, 3 h and 4 h) were investigated, equivalent to organic loadings of 1.11 and 0.78 kg BOD/m3/d, respectively. The average BOD concentration in the final effluent was 46 and 26 mg/L at HRTs of 3 and 4 h, respectively. The concentration of retained sludge along the reactor height was 10.2-18.7 g VSS/L-sponge, and the sludge activities were 0.24-0.32 and 0.04-0.40 mg/g VSS/h for heterotrophs and nitrification, respectively. Values of water hold-up volume, dispersion coefficient, and number of tank in-series found from tracer studies of clean sponge and biomass-loaded sponge confirmed that growth of retained sludge on the sponge module improved hydraulic performance of the reactor. Adoption of the DHS reactor by this Indonesian sewage treatment plant would enhance the role of the current desludging septic tank wastewater treatment system. [ABSTRACT FROM AUTHOR]

Biochar has been identified as a media amendment to improve nutrient removal from wastewater, and N retention and plant growth in agroforestry. It therefore has the potential for treating domestic wastewater. The aim of this research was to compare nitrogen removal and plant growth in pure sand and sand amended with biochar, in wetland mesocosms (240 L) receiving sewage. There were seven media treatments based on the proportions of biochar in the sand media (100% sand, sand and coir peat, 5, 10, 15, 20, 25% biochar). The plant species were Paperback tree ( Melaleuca quinquenervia ) and Lemongrass ( Cymbopogon citratus ). The mesocosms were continuously loaded for 8 months with secondary clarified wastewater (SCW) (16 L/day). Septage was then intermittently loaded (20 L/2 days) for a further 8 months. Inflow and outflow samples were monitored for TN, NH 4 -N, and NO x -N. All treatments showed good nitrogen removal efficiency. Average removal efficiencies of TN, NO x -N and NH 4 -N in the mesocosms loaded with SCW ranged from 71 to 87%, 81 to 93% and 65 to 79%, for 100% Sand to 25% Biochar respectively. For septage, the removal efficiencies ranged from 63 to 81%, 69 to 87% and 66 to 81%, for 100% Sand to 25% Biochar respectively. Significant differences of nitrogen outflow concentrations were observed between pure sand and sand amended with biochar. Physical chemical properties of the biochar would have facilitated microbial processes and adsorption. Strong positive correlations were observed between biochar content in the media and nitrogen removal rates. The increased nitrogen removal may be attributed to higher mineralisation of organic nitrogen and NH 4 -N, especially in the case of septage where strong correlation was observed between BOD 5 and TN removal. Total N biomass in the plants harvested after 21 months ranged from 13.4–14.0 g N. The addition of biochar did not increase plant N biomass in either species. [ABSTRACT FROM AUTHOR]

Sustainable treatment and management of fecal sludge in rural areas require adapted solutions. Rustic and simple operating processes such as sludge treatment reed beds (STRB) have been increasingly considered for this purpose. The biggest full scale (2,600 m² of STRB) septage treatment unit in France had been built in Nègrepelisse with the final objectives of reusing treated sludge and leachates for agriculture spreading and tree irrigation, respectively. The aim of this investigation was to validate the treatment chain of this installation. The obtained field data showed firstly that the overall removal efficiencies of STRB were satisfactory and stable. Removal rates higher than 98% for chemical oxygen demand and suspended solids and a 95% for Kjeldahl nitrogen represented so far a beneficial septage treatment by STRB. The highlighted necessity of a suitable complementary leachate treatment (before tree irrigation) justified the presence of the second stage of vertical flow constructed wetland. The sludge deposit drying and mineralization efficiencies were on the right track. According to hydrotextural diagram analysis, surface deposit was however found to have high deformability probably due to the youth of the installation. An in-depth understanding of STRB system needs continuous long-term studies. [ABSTRACT FROM AUTHOR]

Water quality and sanitation are inextricably linked to prevalence and control of soil-transmitted helminth infections, a public health concern in resource-limited settings. India bears a large burden of disease associated with poor sanitation. Transformative onsite sanitation technologies are being developed that feature elimination of pathogens including helminth eggs in wastewater treatment. We are conducting third-party testing of multiple sanitation technology systems in Coimbatore (Tamil Nadu) India. To ensure stringent testing of the pathogen removal ability of sanitation technologies, the presence of helminth eggs in wastewater across the town of Coimbatore was assessed. Wastewater samples from existing test sites as well as desludging trucks servicing residential and non-residential septic tanks, were collected. The AmBic methodology (based on washing, sieving, sedimenting and floating) was used for helminth egg isolation. We tested 29 different source samples and found a 52% prevalence of potentially infective helminth eggs. Identification and enumeration of helminth species is reported against the septage source (private residential vs. shared toilet facility) and total solids content. Trichuris egg counts were higher than those of hookworm and Ascaris from desludging trucks, whereas hookworm egg counts were higher in fresh wastewater samples. Surprisingly, no correlation between soil transmitted helminth eggs and total solids was observed. [ABSTRACT FROM AUTHOR]

In this study, a combination of substrate rich carbon with substrate rich nitrogen was carried out. The experiments were conducted in batches process by varying the C/N ratio and types of anaerobic microbial sludge of the cow rumen, anaerobic microbial sludgefrom wastewater treatment plant (WWTP) of septage and anaerobic sludge from WWTP of tapioca industry. Practically in the range of C/N ratio 20-30 didn't give a significant effect on the biogas production. The C/N 30 ratio provides the most biogas production rate, while the microbe derived from the cow rumen gives the most biogas production rate. Adaptation phase occurred up to 11thdays, growth phase occurred lasted until day 24st, stationary phase occurred in the range of day 24th-31st and death phase occurred after day 31st. Biogas yield (by cow rumen) is 1,127 liters per kg of COD removed or 161 liters per kg of COD per day. [ABSTRACT FROM AUTHOR]

Septage is wastewater stored temporarily in cesspools. A periodic supply of its significant quantities to small municipal wastewater treatment plants (WWTPs) may cause many operational problems. In the frame of the research, it has been proposed to utilize vertical flow constructed wetlands for pretreatment of septage prior to its input to the biological stage of a WWTP. The aim of the work was to assess the effectiveness of pre-treatment in relation to factors such as: seasonality, hydraulic load, pollutants load of the VF bed and interactions between these factors. The results proved that application of a VF bed to septage pre-treatment can significantly reduce the concentration of pollutants (biochemical oxygen demand (BOD5): 82%, chemical oxygen demand (COD): 82%, total suspended solids (TSS): 91%, total nitrogen (TN): 47%, ammonia nitrogen (NH4-N): 70%), and thus decrease the loading of the biological stage of a WWTP. The mathematical models of mass removal process were created. They indicate that in case of all analysed parameters, removed load goes up with the increase of load in the influent. However, with the increase of hydraulic load, a decrease of the removed BOD5, COD, TSS and total phosphorus, and in vegetation period an increase of TN, can be observed in terms of load. There are no statistically significant effects of seasonality. [ABSTRACT FROM AUTHOR]

A combined reed bed-freezing bed (RB-FB) technology was effective at treating septage under Canadian climatic conditions over a 5-year period with average loading rates of 82-104 kg TS/m2/y. Varying hydraulic and solid loading rates as well as the increasing sludge cake with time had little to no effect on treatment efficiency, with almost complete removal of organic matter, solids, heavy metals and nutrients. Filtrate concentrations varied significantly between the freeze-thaw and growing seasons for many parameters, although the differences were not important from a treatment or reuse perspective with filtrate quality similar to a low to medium strength domestic wastewater. The potential to reuse the filtrate as a source of irrigation water will depend upon local regulations. The dewatered sludge cake consistently met biosolids land application standards in terms of pathogen and metals content, with Escherichia coli numbers declining with time as sludge cake depth increased. A combined RB-FB technology can provide a cost-effective solution for septage management in northern rural communities with potential for beneficial reuse of both the filtrate and dewatered sludge cake. [ABSTRACT FROM AUTHOR]

Septage is the solid sludge that accumulates in septic tanks over a period of time. Many of the developing countries in the world face the challenging task of septage management. Due to the high variability in the nature of septage, there is a need to study its physical and chemical characteristics in order to suggest a sustainable treatment methodology. The present study deals with the characterization of septage collected from different locations of Chennai city in India, in two different seasons (summer and winter). The characterization includes parameters such as solids, organics, inorganics, nutrients and heavy metals. Septage showed significant difference in concentrations of pollutants from one season to the other ( p > 0.05). The average total solids concentration is found to be 1.6 times higher during winter season than compared to summer season. Average concentrations of solids were 2185 ± 1070 and 3555 ± 2935 mg/L during summer and winter, respectively. Liquid characterization of septage showed total chemical oxygen demands (COD) of 905 ± 603 mg/L (summer) and 1460 ± 1295 mg/L (winter). Similarly, average soluble biochemical oxygen demand (sBOD) was found to be 117 ± 54 mg/L during summer and 211 ± 220 mg/L during winter season. Studies also showed that septage was rich in nutrients such as total nitrogen (4-500 mg/L), ammoniacal nitrogen (2-129 mg/L), total phosphate (5-236 mg/L) and heavy metals such as copper, zinc, lead and manganese. Overall characterization indicates that the collected septage samples are highly variable in nature with respect to sources, season and locations of collection. As the septage is rich in organic matter and nutrients, it can be used as a resource like soil conditioner or as a substitute for chemical fertilizer in agriculture, after proper treatment, leading to a new evolution in sanitation. [ABSTRACT FROM AUTHOR]

Sanitation systems have vast differences among the countries as well as among different regions within the country. In Sri Lanka, over 90% of buildings rely upon onsite sanitation systems and most popularly with water sealed latrines connected to septic tanks or cesspits, however, the sanitizing the septage or nightsoil is required further treatment before disposing of or reuse. The filled cesspits/septic tanks are simply emptied using the suction trucks by the local authorities. Since the septage is removed from the site, the whole system can be named as partial onsite sanitation system (POSS). The practical problems that POSS may lead to are discussed throughout the paper using two case studies in Sri Lanka. Methodology follows both quantitative and qualitative social research techniques such as structured interviews with operators, downstream community, and health and sanitary workers, and collecting data on influent and effluent characteristics. Quantitative data were analyzed and interpreted using descriptive statistics. This paper provides a description of the complex issues that may stem out of POSS and possible factors for the sustainability of such systems. It is found that community participation, knowledge on sanitation, and institutional commitment were required to sustain the system which were lacking in two cases studied. It is advisable to develop programs and strategies to build up the capacity of local authorities to manage the sanitation systems and even to raise the awareness of community for good care of the onsite components. Key words: Nightsoil; Partially onsite sanitation system; Sanitation; Septage; Septic tanks.DOI: 10.4038/tar.v22i2.2823Tropical Agricultural Research Vol. 22 (2): 144-153 (2011)

To improve the performance efficiency of subsurface constructed wetlands (CWs), a variety of media have been tested. Recently, there has been a rising interest in biochar. This research aims to develop the effectiveness of sand media amended with biochar and two plants species ( Melaleuca quinquenervia and Cymbopogon citratus ) in removing phosphorus from sewage effluent in CWs. The experimental design consisted of vertical flow (VF) mesocosms with seven media treatments based on the proportions of biochar in the sand media which ranged from 0 to 25% by volume. During the first 8 months, the mesocosms were loaded with secondary clarified wastewater (SCW) then septage was used for the remaining 8 months. Inflow and outflow were monitored for total phosphorus (TP) and PO 4 -P. Plants were harvested at the end of the experiment and TP biomass was determined. Removal efficiencies of TP in the mesocosms loaded with SCW and septage ranged from 42 to 91% and 30 to 83%, respectively. Removal efficiencies of PO 4 -P ranged from 43 to − 92% and 35 to 85% for SCW and septage, respectively. The results revealed that the sand media performed better than the biochar-amended media; increasing the proportion of biochar in the media decreased removal efficiency of phosphorus. However, after flushing due to major rain event, there was no significant difference between sand and sand augmented with 20% biochar. Total plant P ranged from 1.75 g in the 20% biochar mesocosm to 2.10 g in the sand only mesocosm. Plant uptake of P, at least in part, may be accredited for the better P removal efficiency in the sand media compared to the biochar-amended media. [ABSTRACT FROM AUTHOR]

Individual septic tanks are the most common means of on-site sanitation in Malaysia, but they result in a significant volume of septage. A two-staged vertical flow constructed wetlands (VFCWs) system for the treatment of septage was constructed and studied in Sarawak, Malaysia. Raw septage was treated in the first stage wetlands, and the resulting percolate was fed onto the second stage wetlands for further treatment. Here, the effects of a batch loading regime on the contaminant removal efficiency at the second stage wetlands, which included palm kernel shell within their filter substrate, are presented. The batch loading regime with pond:rest (P:R) period of 1:1, 2:2 and 3:3 (day:day) was studied. The improvement of the effluent redox condition was evident with P:R = 3:3, resulting in excellent organic matters (chemical oxygen demand and biochemical oxygen demand) and nitrogen reduction. The bed operated with P:R = 1:1 experienced constant clogging, with a water layer observed on the bed surface. For the P:R = 3:3 regime, the dissolved oxygen profile was not found to decay drastically after 24 hours of ponding, suggesting that the biodegradation mainly occurred during the first day. The study results indicate that a suitable application regime with an adequate rest period is important in VFCWs to ensure efficient operation. [ABSTRACT FROM AUTHOR]

This study investigated the performance of sludge drying reed beds (SDRB) at full- and pilot-scale treating sludge from septic tanks in the city of Belo Horizonte, Brazil. The treatment units, planted with Cynodon spp., were based on an adaptation of the first-stage of the French vertical-flow constructed wetland, originally developed for treating sewage. Two different operational phases were investigated; in the first one, the full-scale unit was used together with six pilot-scale columns in order to test different feeding strategies. For the second phase, only the full-scale unit was used, including a recirculation of the filtered effluent (percolate) to one of the units of the French vertical wetland. Sludge application was done once a week emptying a full truck, during 25 weeks. The sludge was predominantly diluted, leading to low solids loading rates (median values of 18 kgTS m–2 year–1). Chemical oxygen demand removal efficiency in the full-scale unit was reasonable (median of 71%), but the total solids removal was only moderate (median of 44%) in the full-scale unit without recirculation. Recirculation did not bring substantial improvements in the overall performance. The other loading conditions implemented in the pilot columns also did not show statistically different performances. [ABSTRACT FROM AUTHOR]

The performance of duckweed and algal systems in removing fecal bacteria, organic matter, and nutrients was evaluated in three full-scale ponds operating in series. Trucks collected septage from holding tanks and discharged it into the system, daily. The inflow rates varied between the warm and the cold season. Duckweed and algae naturally colonized the ponds in two successive periods of 10 and 13 months, respectively. Environmental conditions were determined at various pond depths. Without harvesting, the duckweed system was neutral and anoxic. Alkaline and oversaturation conditions were observed in the algal system. The overall removals of 5-day biochemical oxygen demand, total suspended solids, total nitrogen removal, and orthophosphate (ortho-PO43-) ranged from 94 to 97, 62 to 84, 68 to 74, and 0 to 26%, respectively. The E. coli and enterococci reductions varied between 2.2 to 3.0 and 1.1 to 1.4 log units, respectively. The upper values were always associated with the algal system. [ABSTRACT FROM AUTHOR]

A two-staged engineered wetland-based system was designed and constructed to treat raw domestic septage. Hydraulic loading rates (HLRs) of 8.75 and 17.5 cm/d were studied with four and eight daily dosings at the second stage of the system to investigate the influence of the regimes on septage treatment. Removal of organic matter (OM) was found to be HLR dependent, where the results indicated that the increase of HLR from 8.75 to 17.5 cm/d impaired the overall level of treatment in the wetland units. Effluent of wetland fed at HLR 17.5 cm/d presented significantly lower oxygen reduction potential and dissolved oxygen values than wetland fed at 8.75 cm/d, indicative of the occurrence of less aerobic and reductive conditions in the bed. The reoxygenation capability of the wetland units was found to be heavily affected by the dosing frequency especially under high hydraulic load (17.5 cm/d). NH3-N degradation was found to decrease with statistical importance when the wetland was flushed two times more frequently with smaller batches of influent. The number of hydraulic load fractionings did not seem to affect the level of treatments of OM and ammonia for both the wetlands fed under the lower HLR of 8.75 cm/d. Prediction of hydraulic limits and management of the feeding strategies are important in the vertical type of engineered wetlands to guarantee the treatment performance and minimize the chances of filter clogging. [ABSTRACT FROM AUTHOR]

This paper presents a two-staged, pilot-scale vertical flow engineered wetland-based septage treatment system (VFEWs), which was designed and constructed in Curtin University Sarawak Campus to determine the system efficiency in treatment of septage. The treatment system consists of storage tanks, vertical flow wetlands, and a network of influent and effluent distribution pipes. The first stage of the VFEWs treatment system consists of three vertical flow wetlands placed in parallel to provide pre-treatment to raw septage to reduce solids and organic matters mainly by physical filtration and sedimentation processes. The percolate from the first stage is then further treated in the second stage, with four vertical flow wetlands, each with variation in operational regime and substrate (filter) type. The influences of various system and application-related parameters such as substrate material, presence of plants and plant types, and septage feeding practices (solid loading rate (SLR), batch and intermittent loading, and frequency of daily feeding) on pollutant removal efficiency were studied. Results from the first stage wetlands indicate that the removal of total solids and organic matter (BOD and COD) from the raw septage is promising (> 80%) at both SLR of 100 kg TS/m².yr and 250 kg TS/m².yr, respectively. However, a higher SLR decreased the average NH3-N removal efficiency. The findings on bed clogging assessment during the study period are also presented in this paper. Validation and expansion of these results are carried out with ongoing assessments on the system performance. [ABSTRACT FROM AUTHOR]

In constructed wetlands for wastewater treatment, plants contribute to nutrient removal. However, plant species differ in their ability to tolerate high nutrient loads and accumulate nutrients in biomass. Growth and nutrient accumulation were investigated in two subtropical/tropical plants: melaleuca trees (Melaleuca quinquenervia) and lemongrass (Cymbopogon citratus). These were planted in 240 L mesocosms containing sand media and biochar (0 to 25% by volume). The mesocosms were loaded with tertiary effluent for 4 months, secondary clarified wastewater (SCW) for 8 months and finally septage for 9 months, a total cumulative load of 1060gN m −2 and 320gP m −2. Plant growth, including stem height and girth for melaleuca and leaf regrowth for lemongrass were monitored. Growth rates were higher (0.48 cm/day stem height; 2.22 cm/day leaf regrowth) when irrigated with septage, compared to SCW (0.32 cm/day stem height; 1.14 cm/day leaf regrowth). Plants were harvested at the end of the experiment and the biomass and nutrient content in each part determined. Both melaleuca and lemongrass had very high N and P tissue content: melaleuca leaves 23 mg/gN, 2 mg/gP; roots15mg/gN, 2.1 mg/gP; lemongrass leaves 18 mg/gN,2.2gP; roots 9.5 mg/gN, 2 mg/gP. Annual biomass and nutrient accumulation per plant was 486 g; 5.72 gN; 0.89 gP for melaleuca trees and 180 g; 2.54 gN; 0.39gP for lemongrass, a total nutrient accumulation of 33 g m −2 N and 5 g m −2 P/annum. Plant uptake accounted for 8.6%TN and 4.5%TP of load retained. Biochar amendments did not enhance growth rate nor increase N and P biomass. We postulate that effluent nutrient loads provided adequate nutrients for plant growth even in pure sand media. • Melaleuca and lemongrass were able to tolerate high nutrient loads. • Both plants had high N and P plant tissue content maximising nutrient uptake. • As a woody plant Melaleuca had high biomass and nutrient bioaccumulation. • Plant biomass and nutrient bioaccumulation in lemongrass was low compared to other herbaceous species. • Biochar additions to sand media did not increase plant growth, nutrient content, nor N and P biomass. [ABSTRACT FROM AUTHOR]

A septage bioreactor landfill was constructed and operated at a publicly owned landfill in the U.S. state of Michigan. Residential septage was processed onsite and injected into municipal solid waste (MSW) using subsurface injection lines (for supernatant) and surface infiltration pits (for sludge) to accelerate the solid waste-decomposition process. For comparison, a leachate bioreactor landfill was also constructed and operated onsite. By comparing the system performance from both bioreactors, the impact of septage addition was identified. Extensive datasets consisting of parameters such as waste temperature, waste-moisture content, leachate quality, landfill gas generation, and waste settlement were systematically evaluated. The waste temperature in both bioreactors was in accordance with a similar trend. Using leachate addition, the waste-moisture content in the leachate bioreactor was controlled to maintain similar moisture content as the septage bioreactor. Using a first-order decay model, the gas-generation rate coefficients (first-order decay coefficient) were estimated at 0.296 and for the septage bioreactor and leachate bioreactor landfills, respectively. This project demonstrated that waste-decomposition rate can be accelerated by septage addition and septage can be processed and treated in the septage bioreactor safely and effectively. [ABSTRACT FROM AUTHOR]

Almost half of Indonesia's 238 million people live in urban areas, and most urban dwellers use on-site sanitation systems. Government policy recognizes the need for effective septage management systems but most existing septage treatment facilities are operating sub-optimally and less than 4 per cent of the faecal sludge generated is currently treated. This paper outlines the findings of field investigations of septage management in four cities undertaken by the World Bank's Water and Sanitation Program (WSP) as part of technical assistance to the Indonesian government. It summarizes the current faecal sludge management arrangements in the four cities, focusing particularly on the consequences of low demand for the financial viability of business models. Models based on 'on-demand' and scheduled tank desludging are explored in relation to their institutional and financial resource needs. The paper explores options for strengthening management systems and proposes an incremental approach to service improvement. [ABSTRACT FROM AUTHOR]

The use of raw sludge spread on land as conditioner and fertilizer has been practised over the years in urban agriculture. However, this raw sludge (biosolids) is associated with a potential health risk as a result of the pathogenic microorganisms it contains. The study considered the dewatering of faecal sludge (FS) mixed with sawdust to produce biosolids that can be applied as manure for agricultural use. It assessed the bacterial and helminth egg qualities of the biosolids produced from FS-sawdust mixture. Bench-scale unplanted filter beds were used for dewatering of ES mixed with different percentages of sawdust. The sludge consisted of public toilet sludge and septage in the ratio of 1:3. An analysis of variance of the completely randomized design was undertaken and a P-value below 0.05 was considered statistically significant. The sawdust-FS mixture analysed after complete dewatering showed significant reductior in microbial (bacteria) content (P < 0.05) and helminth eggs. making the biosolids produced safe for farmers and the environment. The bulking agent improved the quality of the biosolids, with greatest pathogen removal observed in the 150% sawdust whilst the least reduction was recorded in the 0% sawdust (control). [ABSTRACT FROM AUTHOR]

Abstract: This work was designed to study the hydraulic properties of sludge deposit, focusing on the impact of operating conditions (i.e. loads and feeding frequencies) on air entrance (aerobic mineralization optimization) into the sludge deposit. The studied sludge deposits came from six 2m2 pilot-scale SDRBs that had been in operation for 50months with three different loads of 30, 50, and 70kg of SSm−2 y−1. Two influents were assessed (i.e. activated sludge and septage) presenting different characteristics (i.e. pollutant contents, physical properties…). Two experimental approaches were employed based on establishing the water retention curve (capillary pressure versus volumetric water content) and the hydrotextural diagram to determine the hydraulic properties of sludge deposit. The study obtained valuable information for optimizing operating conditions, specifically for efficient management of loading frequency to optimize aerobic conditions within the sludge deposit. [Copyright &y& Elsevier]

Abstract: This paper focuses on the feasibility of septage treatment by sludge drying reed beds (SDRB). Different designs and operation conditions of SRDB pilot-scales were tested on system efficiencies such as the top filtration layer (sand or compost) and the organic load (30 and 50kg SSm−2 y−1). Results focus on the obtained performances considering sludge characteristics, filtration efficiencies, percolate qualities, and sludge deposit properties. Although results show better filtration efficiency for activated sludge (e.g. SS removal around 98.4%) than for septage (e.g. SS removal around 87.5%), the feasibility of septage treatment with SDRB has been demonstrated with, at 50kg SSm−2 y−1 sludge accumulation, and dry matter about 7.9cmy−1 and 70% (summer period), respectively. Further design and operation condition recommendations for SDRB treating septage are proposed. [Copyright &y& Elsevier]

Environmental conditions and wastewater treatment performance in a full-scale duckweed pond system are presented. The treatment system consisted of three stabilization ponds in series and was fed with septage. Vacuum trucks pumped the septage from residential holding tanks and discharged it to the system daily. The inflow rates averaged 36 m3 d-1 in the cold season and 60 m3 d-1 in the warm season. Duckweed (Lemna minor) colonized the ponds in the warm months and survived during the cold season. Because of the difficult process for harvesting the duckweed biomass, the investigation of the treatment efficiency was carried out without plant harvesting. Samples were collected from the vacuum trucks and from the exit of each pond and were analysed for physicochemical and microbiological parameters over a period of 12 months. The results showed that the duckweed mat suppressed algal biomass, which in turn led to anoxic and neutral pond conditions. On an annual basis, the duckweed system sufficiently removed BOD5 (94%), NH4+ (72%) and E. coli (99.65%), with lower removal of TSS (63%) and Enterococci (91.76%). A slight increase (1.1%) was recorded for o-PO43-. Between the two sampling seasons, BOD5 and TSS removal efficiencies were higher in the cold season with the longer retention time. Similar removal values in the warm and the cold season were found for nutrients and bacteria. These findings indicate that BOD5 and TSS removals are less temperature-dependent at higher retention times, while ammonia nitrogen and bacterial removals are substantially influenced by temperature as well as retention time. [ABSTRACT FROM AUTHOR]

Abstract: Fecal indicators such as Escherichia coli and enterococci are used as regulatory tools to monitor water with 24 h cultivation techniques for possible input of sewage or feces and presence of potential enteric pathogens yet their source (human or animal) cannot be determined with routine methods. This critical uncertainty has furthered water pollution science toward new molecular approaches. Members of Bacteroides genus, such as Bacteroides thetaiotaomicron are found to have features that allow their use as alternative fecal indicators and for Microbial Source Tracking (MST). The overall aim of this study was to evaluate the concentration and fate of B. thetaiotaomicron, throughout a wastewater treatment facility and septage treatment facility. A large number of samples were collected and tested for E. coli and enterococci by both cultivation and qPCR assays. B. thetaiotaomicron qPCR equivalent cells (mean: 1.8 × 107/100 mL) were present in significantly higher concentrations than E. coli or enterococci in raw sewage and at the same levels in raw septage. The removal of B. thetaiotaomicron target qPCR signals was similar to E. coli and enterococci DNA during the treatment of these wastes and ranged from 3 to 5 log10 for wastewater and was 7 log10 for the septage. A significant correlation was found between B. thetaiotaomicron marker and each of the conventional indicators throughout the waste treatment process for both raw sewage and septage. A greater variability was found with enterococci when compared to E. coli, and CFU and equivalent cells could be contrasted by various treatment processes to examine removal and inactivation via septage and wastewater treatment. These results are compared and contrasted with other qPCR studies and other targets in wastewater samples providing a view of DNA targets in such environments. [Copyright &y& Elsevier]

Composite samples of septage discharging at the Khirbit As-Samra municipal wastewater treatment plant were analyzed during the period from February to the end of October 2007. Septage showed difference in concentrations of pollutants between summer and winter. The average total chemical oxygen demand (COD) of 6,425 mg/L during summer was 2.16 times greater than that in winter, which is 2,969 mg/L. The total biochemical oxygen demand (5 d) represented 45% of total COD in both winter and summer. Anaerobic biodegradability was 75% after 81 d of digestion at 35°C with a biodegradation rate constant ( k) of 0.024 d, which was lower compared with 0.103 d calculated for wastewater with domestic origin in Jordan. Aerobic biodegradability for septage was 48%-COD basis-after 7 d of digestion at 35°C. The lower anaerobic biodegradation rate of septage compared with that of raw wastewater of domestic origin suggested that septage could have a negative effect on the performance of a domestic wastewater treatment plant if septage discharges are not taken into account in the original design of the treatment plant. [ABSTRACT FROM AUTHOR]

Abstract: In a pre-existing wastewater treatment pilot plant consisting of three interconnected waste stabilization ponds –a facultative pond followed by two maturation/aerobic ones – and located in Sindos near Thessalonica, Northern Greece, we introduced eight vertical flow constructed wetlands, identical in couples, that differ in substrate and plant presence and are fed from the outflow of the first maturation pond. This resulted in the creation of a combined waste stabilization ponds–constructed wetland system, which was being monitored systematically for 2 years in order to study its operation. The unit was fed with septage. The monitored parameters were BOD5, pH, conductivity and TSS. This article presents the results obtained from the aforementioned unit, which are juxtaposed to results recorded in the literature for systems with similar characteristics, before focusing on the differences recorded in the results due to the different characteristics of the wetlands (different substrates, presence or absence of plants). To evaluate the system efficiency, results obtained from the constructed wetlands are compared to respective results recorded from the second maturation pond located in the unit, the inflow of which is the same as that of the wetlands. The constructed wetlands that were left unplanted were the ones which exhibited the highest BOD5 and TSS removal and the lowest conductivities. [Copyright &y& Elsevier]