Conditionnement et déshydratation de boues d'étangs aérés facultatifs à l'aide du gel – dégel naturel: résultats d'essais

1996 ◽  
Vol 23 (2) ◽  
pp. 323-339 ◽  
Author(s):  
Marc-André Desjardins ◽  
François G. Brière
Keyword(s):  
Suspended Solids ◽  
Winter Season ◽  
Oxygen Demand ◽  
Solid Content ◽  
Thin Layers ◽  
Freeze Thaw ◽  
Storage Basin ◽  
Low Levels ◽  
High Chemical Oxygen Demand ◽  
Chemical Sludge

This article presents the results of tests investigating the conditioning and dewatering of biological and chemical sludge (alum dephosphatation sludge) from facultative aerated lagoons using natural freeze–thaw. The results presented here highlight the excellent efficiency of this conditioning method used with drying beds. Following freeze–thaw, immediately after drainage, sludge presents little odor and has lost its liquid state since dry solid contents of more than 30% can be obtained with ease. Freeze–thaw also eliminates the gelatinous consistency of chemical sludge. The filtrates are clear and contain low levels of suspended solids but may have relatively high chemical oxygen demand. To maximize the depth of sludge that can be frozen, it is necessary to freeze the sludge in thin layers. This requires the pumping of sludge from a separate storage basin to a freezing bed for the duration of winter (separate basin–bed method). The storage basin may however be combined with the freezing bed provided the depth of the sole sludge layer does not exceed the maximum depth of sludge that can be frozen during the winter season (combined basin–bed method). Freeze–thaw is not affected by the initial dry solid content of the sludge. The grain size of the sludge can however have some influence, although quite marginal, and freeze–thaw is efficient for all types of aqueous sludge. Key words: conditioning, dewatering, sludge, facultative aerated lagoons, natural freeze–thaw, trials.

scholarly journals Opportunities and challenges for greywater treatment and reuse in Mongolia: lessons learnt from piloted systems

2014 ◽  
Vol 4 (3) ◽  
pp. 182-193 ◽  
Author(s):  
Sayed Mohammad Nazim Uddin ◽  
Zifu Li ◽  
Heinz-Peter Mang ◽  
André Schüßler ◽  
Tobias Ulbrich ◽  
...  
Keyword(s):  
Suspended Solids ◽  
Oxygen Demand ◽  
National Standards ◽  
Who Guidelines ◽  
High Chemical ◽  
Treatment Unit ◽  
User Training ◽  
Environment And Health ◽  
Business Opportunities ◽  
High Chemical Oxygen Demand

In Mongolia, as worldwide, communities are challenged by water scarcity, depletion and pollution. Greywater treatment and reuse could partially meet water demand and help protect the environment and health. In March 2010, greywater from six randomly sampled households in the Ger areas of Ulaanbaatar, Mongolia, was analyzed followed by the development of three innovative treatment systems: an underground (UG-), greenhouse (GH-) and ice-hole greywater treatment unit (IH-GWTU). The UG- and GH-GWTU were implemented to identify opportunities and challenges for future investments in greywater treatment and reuse. Users' and non-users' perceptions, and business opportunities, were assessed. Laboratory analysis showed a high chemical oxygen demand (6,072–12,144 mg/l), N-NH4+ (183.7–322.6 mg/l), PO4− (12.6–88.2 mg/l) and total suspended solids (880–3,200 mg/l) – values exceeding the WHO guidelines and much higher than in any other country: low water consumption combined with traditional diet might be major reasons. Odourless and colourless water after treatment in a UG-GWTU lead to more acceptance than a GH-GWTU. Business opportunities include the use of treated water for irrigation, considering WHO and national standards. Further research focuses on seasonality of installation, technical shortcomings, maintenance, biological quality control and user training.

scholarly journals Comparison of nutrient solubilisation and dewatering by freeze/thaw processing of sludge from Biological Nutrient Removal (BNR) and Non-BNR wastewater treatment plants.

2017 ◽  
pp. 6.1-6.8
Author(s):  
Mahrooz Sabri ◽  
Nazim Cicek ◽  
Qiuyan Yuan
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Low Cost ◽  
Oxygen Demand ◽  
Solid Content ◽  
Cold Climate ◽  
Wastewater Sludge ◽  
Biological Nutrient Removal ◽  
Climate Conditions ◽  
Freeze Thaw

Natural freeze/thaw processing is a simple, practical and low-cost solid-liquid separation method, which can effectively dewater wastewater sludge in Northern Canadian communities located in cold climate conditions. This method is especially effective when used in small treatment plants in remote and cold regions as typical dewatering methods require complex and expensive equipment, skilled operators and special maintenance. The objective of this research was to evaluate freeze/thaw processing as a method for dewatering, nutrient solubilisation and organics separation of wastewater sludge originating from two different wastewater treatment facilities: a Biological Nutrient Removal (BNR) plant and non-BNR plant. The results of experiments showed the effectiveness of this method for sludge dewatering and solubilisation of organics and nutrients. The sludge solid content increased approximately 10-fold after freeze/thaw processing. The treatment solubilised 15.2%, 33.5% and 21.5% of the initial total nitrogen, total phosphorus and total chemical oxygen demand, respectively for the non-BNR sludge. These values were 6.3%, 80.0% and 16.5%, respectively for the BNR sludge. The released phosphorus and nitrogen in the water can be recovered and used as fertilizer for agricultural purposes, supporting northern food production.

scholarly journals An integrated UMAS for POME treatment

2016 ◽  
Vol 8 (1) ◽  
pp. 68-75 ◽  
Author(s):  
N. H. Abdurahman ◽  
N. H. Azhari
Keyword(s):  
Suspended Solids ◽  
Kinetic Equations ◽  
Oxygen Demand ◽  
Growth Yield ◽  
Yield Coefficient ◽  
Mixed Liquor ◽  
Integrated Technology ◽  
Yield Production ◽  
High Chemical Oxygen Demand ◽  
Direct Discharge

Abstract The direct discharge of palm oil mill effluent (POME) wastewater causes serious environmental hazards due to its high chemical oxygen demand (COD) and biochemical oxygen demand. This paper proposes a new approach for integrated technology of ultrasonic membrane for a POME treatment. The paper evaluated the economic viability based on the changes of the new design of ultrasonic membrane anaerobic system (UMAS) when a POME introduces this approach. Six steady states were attained as a part of a kinetic study that considered concentration ranges of 13,800–22,600 mg/L for mixed liquor suspended solids and 10,400–17,350 mg/L for mixed liquor volatile suspended solids. Kinetic equations from Monod, Contois and Chen and Hashimoto were employed to describe the kinetics of POME treatment at organic loading rates ranging from 1 to 15 kg COD/m3/d. throughout the experiment, the removal efficiency of COD was from 92.8 to 98.3% with hydraulic retention time from 500.8 to 8.6 days. The growth yield coefficient, Y, was found to be 0.73 gVSS/g COD, the specific microorganism decay rate was 0.28 day–1 and the methane gas yield production rate was between 0.27 and 0.62 L/g COD/d.

APLIKASI PROSES DIGESTASI ANAEROBIK LUMPUR BIOLOGI INSTALASI PENGOLAHAN AIR LIMBAH INDUSTRI KERTAS

2014 ◽  
Vol 4 (02) ◽  
Author(s):  
Rina S. Soetopo ◽  
Sri Purwati ◽  
Henggar Hardiani ◽  
Mukharomah Nur Aini ◽  
Krisna Adhitya Wardhana
Keyword(s):  
Oxygen Demand ◽  
Total Solid ◽  
Pilot Scale ◽  
Organic Content ◽  
Solid Content ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Organic Loading ◽  
Total Solid Content ◽  
Average Value

A continuous pilot scale study has been conducted to investigate the effectiveness of anaerobic digestion of biological sludge. The sludge has a total solid content of 0.53% - 1.1%, pH of 7.20 to 7.32. Its organic content is about 97 %, The research were conducted in two stages, which are acidification (performed in 3 m3 the Continously Stirred Tank Reactor/CSTR at pH of 5.5 to 6.0) and methanation (performed in 5 m3 the Up Flow Anaerobic Sludge Blanket/UASB reactor at pH 6.5 to 7.0). The retention time (RT) was gradually shortened from 6 days to 1 day for acidification and from 8 days to 2 days for methanation. The results showed that operating the CSTR at the RT of 1 day and the organic loading of 8.23 g Volatile Solid (VS)/m3.day could produce Volatile Fatty Acid (VFA) at an average value of 17.3 g/kg VS.day. Operating the UASB reactor at the RT of 2 days and the organic loading (Chemical Oxygen Demand/COD) of 2.4 kg COD/m3.day could produce biogas at an average value of 66.3 L/day, with an average methane content of 69.9%, methane rate of 0.17 L CH4/g COD reduction or 19.06 L CH4/kg VS. Furthermore, methanation could reduce COD at an average value of 51.2 %, resulting in the effluent average value of COD filtrate and COD total of 210.1 mg/L and 375.2 mg /L, respectively.Keywords: acidification, methanation, CSTR, UASB, biogas ABSTRAKPercobaan digestasi anaerobik lumpur IPAL biologi industri kertas secara kontinyu skala pilot telah dilakukan di industri kertas dengan tujuan mengkaji efektivitas proses digestasi anaerobik dalam mengolah lumpur tersebut. Lumpur yang digunakan memiliki total solids sekitar 0,53% – 1,1%, pH netral (7,20 – 7,32) dengan komponen utama senyawa organik sekitar 97%. Percobaan dilakukan dalam dua tahap yaitu asidifikasi dalam reaktor CSTR berkapasitas 3 m3 pada pH 5,5 – 6,0 dan metanasi dalam reaktor UASB berkapasitas 5 m3 pada pH 6,5 – 7,0. Percobaan dilakukan dengan waktu retensi yang dipersingkat secara bertahap dari 6 hari ke 1 hari untuk proses asidifikasi dan dari 8 hari ke 2 hari untuk proses metanasi. Hasil percobaan menunjukkan bahwa pengoperasian reaktor CSTR dengan waktu retensi 1 hari dan beban organik 8,3 g VS/m3.hari dapat menghasilkan VFA rata-rata 17,3 g/kg VS.hari dengan kisaran 8,36 – 30,59 g/kg VS.hari, sedangkan pengoperasian reaktor UASB pada waktu retensi 2 hari dan beban organik 2,4 kg COD/m3.hari dapat menghasilkan biogas rata-rata 66,3 L/hari dengan kadar metana rata-rata 69,9% atau 0,17 L CH4/g COD reduksi atau 19,06 L CH4/kg VS. Selain itu proses metanasi dapat menurunkan COD terlarut rata-rata 51,2%, dengan konsentrasi efluen COD terlarut  rata-rata 210,1 mg/L dan COD total rata-rata 375,2 mg/L.Kata kunci: asidifikasi, metanasi, CSTR, UASB, biogas

Arsenic removal by MF membrane with chemical sludge adsorption and NF membrane equipped with vibratory shear enhanced process

2003 ◽  
Vol 3 (5-6) ◽  
pp. 303-310 ◽  
Author(s):  
S.-H. Yi ◽  
S. Ahmed ◽  
Y. Watanabe ◽  
K. Watari
Keyword(s):  
Arsenic Removal ◽  
Membrane Surface ◽  
Membrane Process ◽  
Low Concentrations ◽  
Strong Shear ◽  
Low Levels ◽  
Removal Processes ◽  
Removal Of Arsenic ◽  
Concentration Polarization Layer ◽  
Chemical Sludge

Conventional arsenic removal processes have difficulty removing low concentrations of arsenic ion from water. Therefore, it is very hard to comply with stringent low levels of arsenic, such as below 10 μg/L. So, we have developed two arsenic removal processes which are able to comply with more stringent arsenic regulations. They are the MF membrane process combined with chemical sludge adsorption and NF membrane process equipped with the vibratory shear enhanced process (VSEP). In this paper, we examine the performance of these new processes for the removal of arsenic ion of a low concentration from water. We found that chemical sludge produced in the conventional rapid sand filtration plants can effectively remove As (V) ions of H2AsO4- and HAsO42- through anion exchange reaction. The removal efficiency of MF membrane process combined with chemical sludge adsorption increased to about 36%, compared to MF membrane alone. The strong shear force on the NF membrane surface produced by vibration on the VSEP causes the concentration polarization layer to thin through increased back transport velocity of particles. So, it can remove even dissolved constituents effectively. Therefore, As (V) ions such as H2AsO4- and HAsO42- can be removed. The concentration of As (V) ions decreased from 50 μg/L to below 10 μg/L and condensation factor in recirculating water increased up to 7 times by using NF membrane equipped with VSEP.

Aeration and Water Hyacinths in Waste Stabilization Ponds

1987 ◽  
Vol 19 (12) ◽  
pp. 265-271
Author(s):  
P. R. Thomas ◽  
H. O. Phelps
Keyword(s):  
Biochemical Oxygen Demand ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Substantial Improvement ◽  
Additional Treatment ◽  
Coliform Bacteria ◽  
Effluent Quality ◽  
Stabilization Ponds ◽  
Water Hyacinths

The investigation was based on two facultative stabilization ponds initially designed to operate in parallel, and now receive wastewater in excess of their capacities from a fast expanding housing estate in the Caribbean Island of Trinidad. Because of the deterioration of the effluent quality relative to acceptable standards, an attempt was made to upgrade the ponds using water hyacinths at the early stages. However, from the results, it was clear that the introduction of water hyacinths in the test pond did not lead to any substantial improvement in the effluent because of the high loading on the pond. Therefore the ponds were modified to operate in series with surface aerators installed in the first pond. Initially, the effluent quality was monitored in terms of total suspended solids, volatile suspended solids, biochemical oxygen demand, faecal coliform bacteria, pH and dissolved oxygen with aeration in the first pond and no aquatic plants in the second pond. Although there was a significant improvement in the effluent quality, the values remained above the standards. As a result, water hyacinths were introduced in the second pond and the effluent quality monitored together with aeration in the first pond. The effluent quality improved with total suspended solids and biochemical oxygen demand values both as low as 10 mg/l in certain months, but additional treatment was needed to reduce faecal conforms.

Management of Dairy Waste in the Sonoran Desert Using Constructed Wetland Technology

1999 ◽  
Vol 40 (3) ◽  
pp. 57-65 ◽  
Author(s):  
Martin M. Karpiscak ◽  
Robert J. Freitas ◽  
Charles P. Gerba ◽  
Luis R. Sanchez ◽  
Eylon Shamir
Keyword(s):  
Sonoran Desert ◽  
Suspended Solids ◽  
Waste Treatment ◽  
Oxygen Demand ◽  
Dairy Wastewater ◽  
Chemical Parameters ◽  
Treatment Facility ◽  
Physical Chemical ◽  
Scirpus Validus ◽  
Surface Wetland

An integrated wastewater treatment facility, consisting of upper (solids separators, anaerobic lagoons, and aerobic ponds) and lower (wetland cells) subsystems, has been built to replace the lagoon at a dairy in Arizona, USA. The collection sump of the new waste treatment facility collects all dairy wastewater outflow. Wastewater is then pumped to solids separators, and flows by gravity to anaerobic ponds and aerobic ponds. The upper subsystem is expected to treat the water sufficiently so that the wetland cells may achieve further pollutant reductions. The lower subsystem, comprised of 8 surface wetland cells with an approximate surface area of 5,000 m2, receives outflow from the ponds. The cells are planted with cattail (Typha domingensis), soft-stem bulrush (Scirpus validus), and reed (Phragmites australis). After treatment is completed via the lagoons and ponds followed by the wetland cells, the wastewater can be reused to flush barns or to irrigate crops. Performance of the overall system is evaluated by measuring physical, chemical and biological parameters in water samples taken from selected locations along the treatment system. Chemical parameters studied include biochemical oxygen demand, pH, total suspended solids, nitrogen species. Biological monitoring included coliforms (total and fecal) and Listeria monocytogenes.

Evaluating the treatment performance of a full scale Activated Sludge Plant in Islamabad, Pakistan

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
S. S. Fatima ◽  
S. Jamal Khan
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Full Scale ◽  
Operational Parameter ◽  
Mixed Liquor ◽  
Treatment Performance

In this study, the performance of wastewater treatment plant located at sector I-9 Islamabad, Pakistan, was evaluated. This full scale domestic wastewater treatment plant is based on conventional activated sludge process. The parameters which were monitored regularly included total suspended solids (TSS), mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), biological oxygen demand (BOD), and chemical oxygen demand (COD). It was found that the biological degradation efficiency of the plant was below the desired levels in terms of COD and BOD. Also the plant operators were not maintaining consistent sludge retention time (SRT). Abrupt discharge of MLSS through the Surplus Activated sludge (SAS) pump was the main reason for the low MLSS in the aeration tank and consequently low treatment performance. In this study the SRT was optimized based on desired MLSS concentration between 3,000–3,500 mg/L and required performance in terms of BOD, COD and TSS. This study revealed that SRT is a very important operational parameter and its knowledge and correct implementation by the plant operators should be mandatory.

scholarly journals Treatment performances of French constructed wetlands: results from a database collected over the last 30 years

2015 ◽  
Vol 71 (9) ◽  
pp. 1333-1339 ◽  
Author(s):  
A. Morvannou ◽  
N. Forquet ◽  
S. Michel ◽  
S. Troesch ◽  
P. Molle
Keyword(s):  
Constructed Wetlands ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Vertical Flow ◽  
Removal Rates ◽  
Waste Stabilization Ponds ◽  
Small Communities ◽  
Technical Department ◽  
In Series ◽  
High Chemical Oxygen Demand

Approximately 3,500 constructed wetlands (CWs) provide raw wastewater treatment in France for small communities (<5,000 people equivalent). Built during the past 30 years, most consist of two vertical flow constructed wetlands (VFCWs) in series (stages). Many configurations exist, with systems associated with horizontal flow filters or waste stabilization ponds, vertical flow with recirculation, partially saturated systems, etc. A database analyzed 10 years earlier on the classical French system summarized the global performances data. This paper provides a similar analysis of performance data from 415 full-scale two-stage VFCWs from an improved database expanded by monitoring data available from Irstea and the French technical department. Trends presented in the first study are confirmed, exhibiting high chemical oxygen demand (COD), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN) removal rates (87%, 93% and 84%, respectively). Typical concentrations at the second-stage outlet are 74 mgCOD L−1, 17 mgTSS L−1 and 11 mgTKN L−1. Pollutant removal performances are summarized in relation to the loads applied at the first treatment stage. While COD and TSS removal rates remain stable over the range of applied loads, the spreading of TKN removal rates increases as applied loads increase.

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