On-site Treatment of Black Waste Water –An Overview

On-site Treatment of Black Waste Water –An Overview

M.AmuthaP.G Scholar, Anna University Tirunelveli

Tamil Nadu , [email protected]

Dr.S.Adish kumarProfessor, Anna University Tirunelveli

Tamil Nadu, India

Abstract—On-site wastewater treatment poses a challenging problem for engineers. It requires a balance of appropriate levels of technology and the operational complexity necessary to obtain high-quality effluent together with adequate reliability and simplicity to accommodate infrequent maintenance and monitoring. This review covers how these issues have been addressed in on-site wastewater treatment worldwide. This work presents the overview of online treatment of black waste water and its application in various perspectives. The different types of reactors used in water treatment are also reviewed in order.

Keywords Black Water , Reactor and Urine Treatement

I. INTRODUCTION

The primary purpose of a wastewater system is to provide a good sanitary environment in and around the home. This can be done in many different ways. A common solution for single-family homes outside urban areas has been to infiltrate the wastewater into the ground, after treatment in a septic tank. This is safe as long as the wastewater is discharged below the surface, and soil conditions and groundwater levels are appropriate. In the last decade, it has become more common to view wastewater as a resource. In the first place, water itself is regarded as a limited resource. Also, there is increased recognition that the nutrients in wastewater can be recycled through agriculture if the material can be properly disinfected. This has led to the development of new wastewater technologies, including source-separating systems in which either urine or blackwater (urine + feces) is collected separately. In this way, between 70 to 90% of all the nutrients in wastewater can be collected and used in agriculture.

The importance of urine separation is recognized but the effect on central treatment processes has not yet been quantified. Separate urine collection would not be worthwhile if it only had a marginal impact on central wastewater treatment systems. Improvement of the overall wastewater management system should be a stronger driving force than nutrient recovery alone. If it can be shown that advanced treatment processes would benefit from separate urine collection, then wastewater treatment in general would benefit form urine separation. Most advanced wastewater treatment works operate according to variants of the modified UCT process.

The different studied systems have been chosen to illustrate different strategies for nutrient recovery. All systems are assumed to achieve a high degree of removal of organic matter, phosphorus (> 90%), nitrogen (> 90%), and nutrient recovery.

II. LITERATURE REVIEW

A. Urine Treatment By Biological Purification

The amount of water consumed in space station operations is very large. In order to reduce the amount of water which must be resupplied from Earth, the space station needs to resolve the problems of water supply. For this reason, the recovery, regeneration and utilization of urine of astronauts are of key importance. This research [3] is based on biological absorption and, purification using UV photo catalytic oxidation techniques to achieve comprehensive treatment for urine. In the treatment apparatus we created, the urine solution is used as part of the nutrient solution for the biological components in our bio regenerative life support system. After being absorbed, the nutrients from the urine were then decomposed, metabolized and purified which creates a favorable condition for the follow-up oxidation treatment by UV photo catalytic oxidation. After these two processes, the treated urine solution reached national standards for drinking water quality .

The new urine purifying apparatus includes three parts: Part I is used for growing Azolla and accomplishes biological purification of the urine. Part II includes an absorbing and filtering column. Part III is a photocatalytic-oxidation reactorthat consists of a UV light lamp and TiO2 sheet .The urine solution is added from the top layer of multilayer Azolla growing pans (Part I). In this step, nutrient and potentially harmful ions are absorbed and enriched by Azolla, and then the treated solution is pumped by pressure into filtering column (Part II). In Part II, the suspended particles in the water–urine mixture are removed by the poly-pored filler. Then the solution goes to the photocatalytic- oxidation reactor (Part III). In Part III, the remaining harmful matter in the urine solution is removed under the combined reactions of UV rays and from the TiO2 sheet. The final product, the treated

13-14 May 2011 B.V.M. Engineering College, V.V.Nagar,Gujarat,India

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solution, reaches standards set for drinking water, and can be reused directly by astronauts. The layout of urine purification instruments is shown below.

This study tested a comprehensive treatment to urine solution with biological purification using Azolla and UV photocatalytic oxidation by TiO2. After these treatments, the urine solution reached the standards for drinking water quality, Table compares the urine solution and drinking water standards. This study shows a new method and valuable reference for achieving urine and sewage water treatment, especially for space life support application. In that context, the process also has potential to provide a supplementary O2 supply for the space station as a by-product of urine treatment and recycling for potable water production.

B. Electrochemical Treatment Of Human Urine

This work [4] proposed the electrochemical treatment of human urine to enable its storage without the accompanying unpleasant odor. This urine can then be reused as flush water in toilets as a means to tackle water shortage problems. In laboratory-scale experiments, the time-dependent variation in the pH of human urine, after the addition of urease, could be suppressed by chlorine produced via the electrochemical treatment of diluted human urine. Ureolysis was quantified by pH increase within 100 h. This suppression occurred as a result of an irreversible change in the conformation of urease that resulted in its inactivation at an oxidation-reduction potential (ORP) of ca. 240 mV or above. Due to the electrochemical inactivation of urease during the entire storage period of urine, the hydrolysis of urea in urine, which results in the production of the unpleasant odor due to ammonia

formation, can be avoided. Thus, the treatment enables the storage of urine for its reuse as flush water in toilets.

Dimensionally stable platinum–iridium (PtIr) electrodes #71 (150 mm×35 mm×1 mm) were obtained from Tanaka Kikinzoku (Osaka, Japan). A dimensionally stable platinum (Pt) electrode was purchased from Ishifuku (Tokyo, Japan). The Pt electrode was sandwiched between the PtIr electrodes with a distance of 5 mm to set up an electrode system (PtIr/Pt/PtIr). Then, 80 mL of urine solution was electrochemically treated at a constant current of 0.8 A (40 mA/cm2). All the treatment experiments were performed at room temperature. The first series of electrochemical treatment was performed for approximately 60 s by using a single urine sample at various dilutions (1/5–1/20) with the PtIr/Pt/ PtIr system where PtIr was operated as the anode. During the treatment, fractions of the solution were occasionally withdrawn and 2.2 μL of urease (1.0 g/L) was added to 1 mL of the solution; the pH of the solution was then monitored initially and after 100 h. The ORP (vs. Ag/AgCl in 3.33 mol/L KCl) and pH were measured with a portable multi-parameter meter (D- 50, HORIBA, Japan). ORP and pH were calibrated occasionally during measurements using standard solutions recommended by HORIBA. The total chlorine was measured as described above. A second series of repetitive electrochemical treatment was performed using the same electrode system by using a urine sample that was diluted 10 times first, with 300mMNaCl and then with the urine sample previously electrochemically treated for 5 s to 6 min, using a longer treatment time as the number of the repeated cycles increased. In this experiment, two urine samples were successively treated. This dilution was selected because it was considered to be acceptable on application to actual toilets, and foaming during the electrochemical treatment was negligible at this or higher dilution. The successive treatment was repeated 40 times. During each treatment, a fraction of the solution was added to urease, and the pH shift within 100 h was measured.

The variation in Trp fluorescence with the successive addition of 0.5% NaClO is shown in above Fig. As observed in the figure, chlorine (assumed to be free chlorine in this experiment because nothing that forms combined chlorine was included in the solution) was confirmed to be the cause of

urease inactivation as the △pH was constant at 3.0 mg/L of

total chlorine concentration—[t-Cl2].Concomitantly, the



intensity of Trp fluorescence decreased and remained constant.

Urea was electrochemically treated in order to suppress the emission of the unpleasant odor due to ammonia, which is an end product of the hydrolysis of urea in urine by urease. As a result of the electrochemical reaction, the reactivity of urease was found to be suppressed when the ORP (oxidation-reduction potential) was maintained at 240 mV or above. Thus, urine can be stored under continuous electrochemical treatment without emitting the unpleasant ammonia odor and thus serve as toilet flush ‘water’. When assuming a 20-L tank is employed (with the entire contents being used to flush the urine passed by one adult), the electricity cost is lower than the tap water charge until the treatment cycles reached 64. This means that only 20 L of water is necessary during 2 months of operation and therefore that the electrochemical storage system contributes to the conservation of a precious natural resource—water.

C. Autotrophic Nitrogen Removal From Black Water

Black (toilet) water [5] contains half of the organic load in the domestic wastewater, as well as the major fraction of the nutrients nitrogen and phosphorus. When collected with vacuum toilets, the black water is 25 times more concentrated than the total domestic wastewater stream, i.e. including grey water produced by laundry, showers etc. A two-stage nitritationean ammox process was successfully employed and removed 85%e89% of total nitrogen in anaerobically treated black water. The (free) calcium concentration in black water was too low (42 mg/L) to obtain sufficient granulation of anammox biomass. The granulation and retention of the biomass was improved considerably by the addition of 39 mg/L of extra calcium. This resulted in a volumetric nitrogen removal rate of 0.5 gN/L/d, irrespective of the two temperatures of 35 �C and 25 �C at which the anammox reactors were operated. Nitrous oxide, a very strong global warming gas, was produced in situations of an incomplete anammox conversion accompanied by elevated levels of nitrite.

In this study the two-stage nitritationeanammox process was applied to remove nitrogen from anaerobically treated source-separated black water, produced from vacuum toilets with a flushing volume of only 5 L/p/d (Meulman et al., 2008). This wastewater is about 25 times more concentrated, with respect to nitrogen, than the total wastewater stream from Dutch households, which includes grey water and flushing with conventional toilets (124 L/p/d (Kanne, 2005)). During anaerobic treatment, COD in this black water is reduced from 7.7 to 9.7 gCOD/L to 1.2e2.4 gCOD/L, but the liquid effluent still contains readily biodegradable organic material (0.48e0.87 g BOD5/L) for which aerobic post-treatment is required (de Graaff et al., 2010b). Nitrogen and COD concentrations (1e1.5 gN/L and 1.2e2.4 gCOD/L) are considerably higher compared to digested domestic sludge liquors (0.6e1 gN/L and 0.1e0.8 gCOD/L) (e.g. Hellinga et al., 1998; Caffaz et al., 2006). The two-stage nitritationeanammox process was chosen in this study to allow the independent study of the application of the separate processes (van der Star et al., 2007). Also, a separate reactor for partial nitritation may remove biodegradable organic material that otherwise could interfere negatively with the anammox process by stimulating

heterotrophic denitrification (Udert et al., 2008). The aerobic conditions in the partial nitritation reactor also may enhance (bio-)flocculation of organic and colloidal material (Wile´n et al., 2004), which therefore can easily be separated from the black water before it is treated in the anammox reactor. In a sequencing batch reactor (SBR) start up and stable operation of the anammox process was evaluated at 25 �C and 35 �C. In view of its environmental impact (Kampschreur et al., 2008), also the emission of greenhouse gas nitrous oxide (N2O) was included in this study. Emission of N2O from the new sanitation concept would have a negative impact on its sustainability and therefore should be avoided. Because of its low growth rate, excellent biomass retention is essential for anammox reactors, and the formation of granules therefore is desired (Strous et al., 1998). The presence of sufficient amounts of calcium stimulates granule formation and thus biomass retention. van der Star et al. (2008) reported growth of anammox in free cells rather than in granules at a calcium concentration of only 41 mg/L. In the anaerobically treated black water used in this research, calcium concentrations were similar to van der Star et al. (2008) (41e44 mg/L, results to be published). The effect of calcium concentration and the addition of calcium on granulation of anammox biomass were therefore also studied in this research.

The two-stage nitritationeanammox process removed 85%e89% of total nitrogen from anaerobically treated black water. The presence of calcium was crucial for granule formation to obtain high biomass retention and therefore an increasing removal of nitrogen in the reactors. The (free) calcium concentration in black water was too low (42 mg/L) to apply granular processes and addition of extra calcium was necessary to obtain a nitrogen removal of 0.5 gN/L/d both at 35 �C and 25 �C. The specific activity of anammox biomass was lower at 25 �C, but with an efficient biomass retention, operation at elevated temperatures (35 �C) is not necessary and energy for heating can be saved. � Nitrous oxide (N2O) was produced in both anammox SBRs, however only when the nitrite concentration increased because of an inefficient anammox conversion process. By preventing nitrite accumulation in the anammox reactor, N2O emissions can be prevented.

D. Black Water And The Emission Of Nitrous Oxide

Black water [6] (toilet water) contains half the load of organic material and the major fraction of the nutrients nitrogen and phosphorus in a household and is 25 times more concentrated,



when collected with a vacuum toilet, than the total wastewater stream from a Dutch household. This research focuses on the partial nitritation of anaerobically treated black water to produce an effluent suitable to feed to the anammox process. Successful partial nitritation was achieved at 34 �C and 25 �C and for a long period (almost 400 days in the second period at 25 �C) without strict process control a stable effluent at a ratio of 1.3 NO2-N/NH4-N was produced which is suitable to feed to the anammox process. Nitrite oxidizers were successfully outcompeted due to inhibition by free ammonia and nitrous acid and due to fluctuating conditions in SRT (1.0–17 days) and pH (from 6.3 to 7.7) in the reactor. Microbial analysis of the sludge confirmed the presence of mainly ammonium oxidizers. The emission of nitrous oxide (N2O) is of growing concern and it corresponded to 0.6–2.6% (average 1.9%) of the total nitrogen load. The partial nitritation reactor was a continuous reactor without intentional biomass retention. The reactor had a volume of 3.2 L, a HRT of 1.3 days and was operated at 34 �C for 231 days. Efficient mixing of reactor contents was provided by an air-lift and at the top the reactor was overflowing. Air was supplied at the bottom at a flow rate of 1.3 L/min, maintaining an oxygen concentration above 2 mg/L and checked daily offline with a portable Hach LDO HQ10 DO meter. Temperature in the water jacketed reactor was controlled by means of a thermo stated water bath (Haake DC10/K10). When the pH exceeded 7.7, automatic 0.1MHCl addition was applied until the pH reached a value of 7.5. Nitrifying sludge from the SHARON reactor at wastewater treatment plant Zwolle (NL) was used as inoculum (3 L, 0.5 gVSS/L). Because the inoculums was acclimated to lower ammonium concentrations (500 mgNH4-N/L, personal communication wastewater treatment plant Zwolle, June 2007), the UASB effluent initially was diluted with tap water to lower the ammonium concentration. The sludge immediately started to convert ammonium to nitrite and after a stable conversion for about a week, the ammonium concentration was increased in steps by decreasing the dilution of the UASB effluent by 3, 2, 1.5 times. From day 50 onward the UASB effluent was no longer diluted. At day 231 the reactor volume was increased to 6.1 L and the temperature was reduced in steps of 1–2 �C every 7 days from 34 �C to 25 �C. This caused an increase in pH and less ammonium conversion to nitrite. When the pH increased to values higher than 7.5, the HRT was increased by reducing the flowrate in steps of 0.14 L/d (0.1 mL/min).

Successful partial nitritation of the ammonium in anaerobically treated source-separated black water was achieved at 34 �C and 25 �C. For a long period (almost 400 days in the second period at 25 �C) a stable influent at a ratio of 1.3 NO2-N/NH4-N was produced and this is suitable to feed an anammox process. No significant nitrate formation was observed during the full period of operation and the nitrite oxidizers were successfully outcompeted due to inhibition by free ammonia and nitrous acid and due to the fluctuating conditions in SRT (from 1.0 to 17 days) and pH (from 6.3 to 7.7) in the reactor. Microbial analysis of the sludge by FISH technique confirmed the presence of mainly ammonium oxidizers. C The emission of nitrous oxide (N2O) corresponded to 0.6– 2.6% (average 1.9%) of the total nitrogen load to the reactor and is of growing concern. C For the application in new sanitation concepts there will be no need for strict process control and partial nitritation of anaerobically treated black water can be achieved easily .

E. Evaluation Of Source Separated Human Urine

G.Sridevi [7] done an attempt was made to study the evaluation of source separated human urine as a source of nutrients for banana cultivation and impact on quality parameter with the following objectives: To study the effect of application of human urine on growth and yield of banana and economics of cultivation; and to study the effect of application of human urine on quality parameters.The field experiment was conducted in the farmer’s field at Nagasandra village, Doddaballapura Taluk, Bangalore using banana (variety Elakki) as test crop with ten treatments and three replications in a randomized block design. The treatments tried were T1-Control,T2-Recommended Dose of Fertilizers (RDF), T3-Recommended Dose of Nitrogen (RDN) through human urine (Basal),T4- RDN through human urine (Basal) + gypsum, T5-RDN through human urine (After 30 days of planting), T6-RDN through human urine (After 30 days of planting) + gypsum, T7- 40% RDN through human urine (Basal) + 60% RDN through Urea, T8- 40% RDN through human urine (Basal) + 60% RDN through Urea + Gypsum, T9- 40% RDN Urea (Basal) + 60% RDN through human urine in 6 splits and



T10- 40% RDN Urea (Basal) + 60% RDN through human urine + gypsum in 6 splits .

Effect of human urine on banana yield (t ha-1

) and qualityA significant difference in length of fruit, diameter of fruit, number of hands per bunch, number of fingers per hand, bunch height and bunch weight of banana was observed due to treatments (Table-1). The highest value was registered under T6 treatment which received RDN through human urine (After 30 days of planting) + Gypsum when compared to RDF and control. This might be due to steady and increased availability of nutrients from human urine resulting in increased uptake by plants and rapid differentiation of the meristem into various floral primordial structures, that determine the future bunch size The different treatments tried in this experiment significantly influenced the banana yield. The highest banana yield (30.0 t ha-1) was recorded in T6 treatment which received RDN through human urine (After 30 days of planting) + Gypsum. But all the other treatments receiving urine with or with out fertilizers were significantly superior over absolute control. This might be due to the improved soil fertility caused by the application of human urine and satisfactory availability of nutrients and more enzymes activity. Another possible reason might be due to the improved soil fertility caused by the application of anthropogenic liquid waste and satisfactory availability of nutrients and more enzymes activity (Hoguland, 2001). Other possible reason is the increased bunch weight is due to a corresponding increase in length of bunch, number of hands, number of fingers length and weight. This is in confirmation with the findings of Ray et al. (1993).The other possible reason for the increased bunch weight is due to a corresponding increase in length of bunch, number of hands, number of fingers length and weight (Table-2).

F. Impact of separate urine collection on wastewater treatment systems

Wastewater treatment should not only be concerned with urban hygiene and environmental protection, but development of a sustainable society must also be considered. This implies a minimisation of the energy demand and potential recovery of finite minerals. Urine contains 80% of the nitrogen (N) and 45% of the phosphorus (P) in wastewater. Separate collection and treatment would improve effluent quality and save energy in centralised biological nutrient removal (BNR). BNR processes are not optimal to treat water with very low N concentration resulting from separate urine collection. Relying on nutrient removal through sludge production, methanation

of the sludge, subsequent nutrient removal from the digestion effluent results in optimised and more sustainable wastewater treatment. This work [8 ] quantitatively evaluates this option and discusses the potential.

A second set of simulations was done to evaluate a proposed system for treatment of separately collected urine and wastewater. Figure 2 presents a flow diagram for the integration of existing processes. Effluent concentrations and removal efficiencies for different process units were based on literature information. The aerobic reactor was simulated as described above. The sum of influent wastewater (Q1), the pre-thickener overflow (Q4) and effluent from the Sharon/Anammox process (Q10) gives the influent flow rate and concentrations (Q3) as shown in Figure 2. The aerobic reactor had a volume of 1000 m3 (hydraulic retention time of two hours). The volume of the clarifier’s sludge compartment was assumed 10% of the volume of the aerobic reactor.

Effect of urine separation on nutrient removal in a BCFS process

The effects of separate urine collection on an existing BCFS process with raw wastewater were simulated. The main results are shown in Figure . Due to a decrease in the number of autotrophic bacteria (nitrifiers), effluent ammonium concentration (NH4 +_eff) increases slightly with increasing urine separation. Effluent nitrate concentration (NO3_eff) decreases with increasing urine separation. The COD/TKN ratio increases with increasing urine separation and therefore the denitrification potential increases. Less nitrate is produced (less ammonium oxidation) while the capacity to reduce nitrate increases. While NO3_eff decreases non-linearly, the amount of nitrogen gas produced decreases linearly with increasing urine separation. Total N in the effluent (Ntot_eff) is the sum of ammonium, nitrate and nitrogen contained in suspended solids (not settled in the clarifier). The model predicts Ntot_eff = 3.2 g/m3 at 50% urine separation, which is the current effluent concentration at Hardenberg, at influent flow rate of 8,500 m3/d compared to 13,500 m3/d in the model simulations. The N removal capacity of a BCFS process can be increased by 60% with 50% urine separation. One observes a substantial decrease in Ntot_eff with urine separation up to 50%. The decrease is less obvious above 50% urine separation. Virtually all phosphate had already been removed in the case of zero urine separation and urine separation therefore had little effect on the P-removal efficiency.



G. Screening Test Battery For Pharmaceuticals In Urine And Wastewater

A test battery for identifying ecotoxicological hazards was applied to six pharmaceuticals (carbamazepine, diclofenac,ethinylestradiol, ibuprofen, propranolol, and sulfamethoxazole), to their mixtures, and to urine spiked with pharmaceuticals to test the suitability of biotests for screening urine and wastewater and for monitoring the efficiency of wastewater treatment.

The test battery comprised the bioluminescence inhibition test with Vibrio fischeri, the yeast estrogen screen, and a photosynthesis inhibition assay in algae based on chlorophyll fluorescence measurements. Mixture and additional experiments with a cocktail of pharmaceuticals added to urine confirmed the applicability of the test systems as an integrated measure of the overall micropollutant burden.Because the concentration of pharmaceuticals in wastewater is low and the nutrients and salts may have a negative impact on the bioassays, urine and wastewater samples were cleaned and concentrated by solid-phase extraction (SPE). The compounds of interest ranged from polar to nonplar and from positively charged to neutral and negatively charged. Consequently, the SPE method was optimized for universality rather than for specificity. Results [ ] of preliminary experiments with raw and treated urine and wastewater indicate the suitability of the proposed test battery for screening urine and wastewater.

The first aim of the present study was to evaluate the effects of six selected pharmaceuticals (carbamazepine, diclofenac,ethinylestradiol, ibuprofen, propranolol, and sulfamethoxazole), both alone and in a mixture. The mixture experiments were used to test the often-stated hypothesis that concentration addition is a realistic worst-case scenario for mixtures in the environment . The second aim of the present study was to test a cocktail of these pharmaceuticals in the presence of urine or wastewater, both to evaluate the matrix effects and to develop an appropriate sample preparation method based on solid-phase extraction (SPE). No cleanup procedure generally is used in whole-effluent toxicity testing when preparing the sample for the toxicity test [8,9]. However, the high concentrations of nutrients, salts, and colored molecules in urine and wastewater made it necessary to introduce such a step. The SPE method developed here also might serve as a cleanup or preconcentration step for more diluted samples, such as wastewater treatment plant effluents and receiving waters. Finally, we show some preliminary results regarding urine and wastewater before and after

treatment in a bioreactor and a wastewater treatment plant, respectively, to discuss the suitability of the proposed test battery for use in site-specific risk assessment and for monitoring the efficiency of wastewater treatment.The proposed screening test battery is suitable for assessing the cumulative impact of pharmaceuticals and other micropollutants in urine, wastewater, and environmental samples after a short cleanup and preconcentration step with SPE. Although whole-effluent toxicity testing usually avoids sample preparation, we showed that SPE was necessary for investigating difficult matrices, such as urine and raw wastewater, and for switching to an appropriate matrix. The latter point is important, because each test system requires a different technique and medium for sample addition. The samples also had to be preconcentrated for the treated urine and wastewater.After careful evaluation, we recommend using LiChrolut EN/ RP-C18 as the solid-phase material and performing the extraction at pH 3. We have already applied this test battery in the Novaquatis project to monitor the efficiency of urine treatment methods with respect to the removal of micropollutants. The first preliminary results are promising: The proposed test battery was successfully used to survey the degradation of selected pharmaceuticals added to urine during treatment with a urine batch bioreactor . In the latter study , a direct comparison with the results of chemical analysis was helpful in interpreting the results and as additional validation for the applicability of the test battery. In the future, we will run further application studies to evaluate the strength and limitations of the proposed test battery for screening of treatment efficiency and compare its performance, advantages, and disadvantages directly with chemical analytical methods.

III. CONCLUSION

Satisfying wastewater treatment needs through on-site treatment requires a multifaceted approach, incorporating technologies ranging from separate waste collection to membrane bioreactors. The feasibility and appropriate implementation of treatment varies greatly depending on location. The different processes involved in urine separation waste water were discussed in this paper. The different types of reactors involved in the black waste water treatment also discussed.

REFERENCES



[1] G. Sridevi, C. A. Srinivasamurthy, S. Bhaskar and S. Viswanath “Evaluation Of Source Separated Human Urine (Alw) As A Source Of Nutrients For Banana Cultivation And Impact On Quality Parameter” ARPN Journal of Agricultural and Biological Science ,VOL. 4, NO. 5, SEPTEMBER 2009

[2] J. Wilsenach and M. van Loosdrecht “ Impact of separate urine collection on wastewater treatment systems” , IWA Publishing Water Science and Technology 2003 ,Vol 48 No 1 pp 103–110.

[3] Xiaofeng Liu , Min Chen , Zuliang Bian , Chung-chu Liu ,” Studies on urine treatment by biological purification using Azolla and UV photocatalytic oxidation” Elsevier Advances in Space Research 41 (2008) 783–786

[4] Mineo Ikematsu , Kazuhiro Kaneda, Masahiro Iseki, Masashi Yasuda ,”Electrochemical treatment of human urine for its storage and reuse as flush water ” Elsevier Science of the Total Environment 382 (2007) 159–164.

[5] M.S. de Graaff , H. Temmink , G. Zeeman a, M.C.M. van Loosdrecht ,C.J.N. Buisman ,”Autotrophic nitrogen removal from black water: Calcium addition as a requirement for settleability” Elsevier Water Research 2010.

[6] B.I. Escher, N.Bramaz, M. Maurer, M.Richter, D. Sutter, C.Ka ̈Nel, and M.Zschokke “Screening Test Battery For Pharmaceuticals In Urine And Wastewater ” Environmental Toxicology and Chemistry, Vol. 24, No. 3, pp. 750–758, 2005

[7] Hernandez Leal, L.; Zeeman, G.; Temmink, H.; Buisman, C. Characterisation and biological treatment of greywater. Water Sci. Technol. 2007, 56, 193-200.

[8] Kujawa-Roeleveld, K.; Zeeman, G. Anaerobic treatment in decentralised and source-separationbased sanitation concepts. Rev. Environ. Sci. Bio/Technol. 2006, 5, 115-139.

[9] Rodríguez Couto S., Domínguez A., Sanromán Photocatalytic degradation of dyes in aqueous



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On-site Treatment of Black Waste Water –An Overview