Latex Factory Research Articles

Pyrolysis of Latex Sediment from Concentrated Latex Industry and Properties of Pyrolytic Products

Concentrated latex is an intermediate rubber product in Thailand. It is an important industry that generates income for the country and Its southern region. The main products of the latex factory were concentrated latex and skim blocks. The industrial waste from the concentrated latex factory is called latex sediment. It appears to be a white mixed light-yellow sludge or a dark brown color, contains magnesium compounds, and phosphorus is an important element. Therefore, finding appropriate measures for rubber production and environmentally friendly industrial waste management is important. Therefore, this study investigates the pyrolysis of latex sediment as an alternative to industrial waste management. Pyrolysis of 100 g of latex sediment was performed at 300 °C, 500 °C, and 700 °C. From the experiment, it was found that the properties of the liquid product from the pyrolysis process at 500 °C were alkaline, with a pH of 9.45. However, acetic acid was the highest amount of organic substance in the liquid product. Substances in the amine and amide groups were also observed, a base result for the liquid product exhibiting an alkaline value. The pH is an important factor in the decomposition of organic substances under anaerobic conditions. Therefore, a 1 wt% liquid product was used in a volume of 13.5 mL, which is the most appropriate amount because it uses the least amount of liquid product to adjust the alkalinity of the skim latex serum before entering the anaerobic fermentation system. Pyrolysis is an environmentally friendly option for managing factory latex sediments for sustainable production and creating a good image for the organization.

Desulfurization of H2S‐rich biogas using water scrubbing: Performance in pilot scale scrubber and scale‐up estimation for the concentrated latex factory

AbstractA high about 3% H2S concentration in the biogas produced from concentrated latex process wastewater needs to be removed before further utilization. Water scrubbing is appropriate for the latex factory having plenty of recycled water available. Effects of liquid to gas (L/G) ratios at 0.5–4.0 on H2S removal were tested at 0.06 m3/h biogas flow rate using a pilot scale scrubber. The experimental results were then simulated to validate the scale‐up for the factory, using the process simulation software Aspen HYSYS (HYSYS, Hyprotech and Systems). The highest 99.71% H2S removal was obtained by using L/G ratio 4.0. Interestingly, using L/G ratio 1.0 provided 96.01% H2S removal, which is slightly lower than on using L/G ratio 4.0, but is more practically appropriate for the real volumes of recycled water and biogas generated from the factory. The experimental data agree with the simulations well. The packed column diameter and height were estimated as 0.5 and 3 m for 40 m3/h biogas. Key characteristics of the scrubber effluent were analyzed for further discharge management. The scrubber effluent qualified for direct discharge to the post‐treatment ponds. This work shows that using recycled water for desulfurization of the H2S‐rich biogas is feasible at atmospheric pressure operation.

Using organosolv pretreatment with acid wastewater for enhanced fermentable sugar and ethanol production from rubberwood waste

The intensive utilization of water in the pretreatment of substrates for lignocellulosic ethanol production negatively impacts its economic feasibility. This study aimed to develop a method of pretreatment using acid wastewater to enhance the conversion of rubberwood waste into fermentable sugar and ethanol. The water was replaced with acid wastewater in hydrothermal pretreatments with and without alkaline post-treatment, and organosolv pretreatment (wastewater:ethanol 50:50). The organosolv pretreatment at 190 °C maximized the fermentable sugar concentration (43.60 g/L) and yield (301.0 ± 13.3 kg/ton rubberwood waste) because of partial delignification and physical redistribution of the rubberwood waste matrix. It also demonstrated markedly better reduction of water utilization, wastewater generation, and energy consumption than other pretreatments. In addition, the hydrolysate derived from the organosolv pretreatment was chosen for ethanol production. Saccharomyces cerevisiae showed better ethanol conversion rate than Kluyveromyces marxianus when the hydrolysate predominantly contained glucose, resulting in an ethanol production of 0.14 g/g rubberwood waste. The pretreatment and fermentation were effective and exhibited the potential to guide lignocellulosic ethanol production in collaboration with latex factories (acid wastewater sources) in future practical applications.

Sulfate removal using rubber wood ash to enhance biogas production from sulfate-rich wastewater generated from a concentrated latex factory

Skim latex serum (SLS) is high-strength wastewater generated from latex processing. Anaerobic treatment of SLS can be enhanced by reducing the sulfate content, which is an inhibitor in the biogas production system. This study investigates the effect of mixing time and rubber wood ash (RWA) loading on sulfate removal from SLS. The optimum sulfate removal efficiency of 42 % was achieved when 10 g/L of RWA was loaded for 10 min. The biogas production efficiency from both desulfated and raw SLS was investigated. The highest 306.36 m L-CH4/g-COD of methane production yield was achieved from desulfated SLS using RWA loading of 10 g/L (DSLS10), which is 16 % higher than the yield generated using raw SLS as a substrate. Moreover, hydrogen sulfide content in the biogas produced by desulfated SLS was two times lower than raw SLS. The results indicate removing sulfate from SLS using RWA before feeding to the anaerobic digestion enhanced biogas production yield and quality.

Cogeneration compressed air energy storage system for industrial steam supply

Factories in China are faced with peak-valley electricity prices and carbon reduction policies nowadays. As the adiabatic compressed air energy storage has a potential to store electricity and provide combined cooling, heating and power, in this paper, a cogeneration system based on it is first proposed to meet the comprehensive energy demands of a latex factory. A new assessment method based on daily energy cost savings is also proposed to evaluate its economic performance. Four novel energy supply strategies based on the cogeneration system and two contrast strategies were analyzed and compared. Results show the energy efficiency of the cogeneration system ranged from 89% to 95%. Besides, energy efficiency and exergy efficiency responded oppositely to the heat-to-electric ratio. In addition, the daily energy costs of the novel strategies were significantly lower than those of the contrast ones. Moreover, the air storage pressure affected the economy the most. Given the ceiling storage pressure of 10 MPa, the optimum floor storage pressure for the air storage was 4.5 MPa. Furthermore, when the cogeneration system provided electricity and dry steam only during the peak load period, its assumed internal return rate reached as high as 10.37%. Therefore, this energy supply strategy is suggested as the most promising choice for the latex factory.

Latex Factory Effluent Treatment Using Biomass Power Plant Fly Ash

This research aims to study Latex Factory Effluent Treatment Using Biomass from power plant fly ash. The purpose of the study is to compare treated latex factory effluent using fly ash from power plant with that of industrial effluent standard issued by Thailand’s Pollution Control Department. The experiments used Coagulation as chemical treatment method. The experiments were carried out using fly ash with 0, 2, 3, 4, 5 and 6 grams dry weight. The agitation times were 10, 30, 45 and 60 minutes, respectively with the settling time of 30 minutes. The treated water was analysed for the following parameters: pH, turbidity, turbidity, sulfate and conductivity, respectively. The results shown that the best experimental set is Experiment 6, with 6 g fly ash, 60 minutes stirring time and settling time of 30 minutes. The treated turbidity value is 456 NTU COD equivalent to 28000 mg/L, the sulfate content is 23100 mg / L, conductivity is 19590 μs / cm, respectively. The pH value is 5.47 in the experiment 6 with the highest corrected pH possible in this study by adding 6 grams of fly ash with stirring time of 60 minutes. However, other parameters of treated effluent still not meet with industrial effluent standards. Further study and improvement are needed.

Biochemical Methane Potential Assay Using Single Versus Dual Sludge Inocula and Gap in Energy Recovery from Napier Grass Digestion

Potential energy recovery from Napier grass biomass was evaluated in batch mode and later compared with different digestion techniques, i.e., theoretical calculation and anaerobic digester operations. In the first part, different anaerobic digester sludges from pig farm, palm oil mill, and concentrated rubber latex factory, designated as PIG, PALM, and RUB in order, were evaluated for their ability as inoculant for biochemical methane potential (BMP) study. Using the first-order and Gompertz models, PIG and RUB were found to possess highest hydrolysis and methanogenesis activities, respectively. Prior to full BMP test on real biomass, suitable inoculum to substrate ratio (ISR) was identified, where ISR ≥1 g VSinoculum per g VSsubstrate was found statistically equivalent for the Napier grass substrate. Results from a series of BMP assays revealed a far more superior digestibility performance of the dual sludge inoculum over the individual PIG and RUB at 32% and 49%, respectively. The protocol proposed in this study could be used as an evaluation and selection guideline for BMP inoculum. In the second part, these BMP results were compared and contrasted with the theoretical methane potential and methane yields from wet and dry Napier grass digester operations in reference to the recoverable energy of this biomass. Gap between different methods suggests rooms for improvement and utilization of the residue.

Integrative Effects of Sonication and Particle Size on Biomethanation of Tropical Grass Pennisetum purpureum Using Superior Diverse Inocula Cultures

Biogas from the fast growing crop, Pennisetum purpureum, has received considerable attention in Southeast Asia since wastewater and bio-waste materials are almost completely utilized. To overcome slow hydrolysis, a rate-limiting step in anaerobic digestion of lignocellulosic biomass, superior microorganism culture, size reduction, and sonication pretreatment were co-applied. In the first experiment, the selection of anaerobic microbial culture to be used in digestion, so-called inoculum, was carried out. Specific anaerobic activities for hydrolysis and methanogenesis of sludge from different sources, a slurry digester of cattle farm (CF) and a wastewater digester of rubber latex factory (RL) were assessed. Results revealed a remarkable synergistic capability in the combined sludge, adding 10% and 49% to the overall biomethanation efficiency over the individual CF and RL sludges. In the second part, interactive effects of size reduction and sonication intensity were studied. Biomethanation efficiency as methane yield increased by 62% by size and 115% by sonication variation, but when optimally combined an additional gain of 40% was recorded. The regression model generated could estimate the energy yield increase as a function of size and sonication intensity with a satisfactory statistical precision R2 of 0.945.

Teknologi Pembuatan Lateks Dadih Melalui Proses Penggetaran

Obstacles factor to get natural rubber raw materials is less efficient for latex processing into concentrated latex, because it need a long time that 2-3 weeks. Centrifugation method many used by concentrated latex factory because it can concentrate the latex with a short relatively time. While the weakness of the centrifugation method is more expensive if that compared with the curdling. With the weakness centrifugation method and curdling, in this research, making the concentrated latex are used vibration method, with the addition of curdle. The purpose of this research is to get the optimum vibrations speed for the concentrated latex manufactured, the speed of the vibrations are used 150 rpm, 175 rpm, 200 rpm, 225 rpm and 250 rpm. The design are used in this research is Randomized Block Design with 6 treatments was repeated 4 times, then obtained 24 units of the experiment, if there is a real difference, then used the BNT at the level of 5% and the data analysis process using Minitab version 16. the most optimum RPM are used in this research is 225 with a quality approaching the standard .

Preliminary Concentration of Skim Latex and Its Wastewater Use Plate Sheet Microfiltration

Skim latex is a by–product of the concentrated latex factory. In this study, plate sheet membrane and cross–flow microfiltration (MF) experiments on skim latex and its wastewater were carried out to initially identify the performance of membrane separation. The series of MF experiments were conducted by using a nitrocellulose plate sheet membrane with a pore size of 0.1 μm and 0.45 μm at the pressures driven at 0.5 and 1 bar. The skim latex, skim latex diluted with water and skim rubber wastewater were tested by membrane separation. Sodium dodecyl sulfate (SDS) and cationic polymer were also added to the skim latex and used to combine it with the membrane. The results implied that filtration of skim rubber wastewater with a 0.45 μm membrane at 1 bar pressure gave the highest flux of 152.6 l/m2–hr while the skim latex gave the highest flux of only 1.4 l/m2–hr. When SDS and cationic polymer at 8 mg/l were added to the skim latex and tested, the highest flux was observed to increase as 2.1 and 2.8 l/m2–hr, respectively. When skim latex diluted with 5 and 10 times the amount of water was tested, the highest flux was determined to be 13.9 and 20.8 l/m2–hr, respectively. Using MF to filtrate the skim latex gave 48% SCOD removal. This result reflects that the MF system might be an alternative technology applied in the concentrated latex factory, especially to the rubber skim process.

Investigation of Excess Sludge Generated from Activated Sludge Treatment Plant of Concentrated Latex Factories: An Investigative Case Study in Southern Thailand

Activated sludge technology has been employed for wastewater treatment in the concentrated latex factories in the south of Thailand. This paper highlights the survey results of the excess sludge generated from activated sludge treatment plants of the concentrated latex factories, including sludge generation rate, sludge characteristics, as well as sludge management and its problems. The total number of 11 factories was investigated. The findings showed that 20% of the investigated factories using activated sludge did not know how much the excess sludge generation rate was. With an in-depth investigation, the excess sludge generation rate was determined as for 28 kg/ton concentrated latex product or 10 kg/ton of field latex used in the concentrated latex factories. The excess sludge had a low C/N ratio with an average value of 4.7 and contained N, P, and K with the average of percentage values of 8.0, 2.0, and 1.0% dry basis, respectively. However, the excess sludge consisted of Zn with an average of 3.01% dry basis. 60% of the investigated factories using an activated sludge system had issues concerning the management of excess sludge. Moreover, various aspects of the excess sludge management were discussed and lessons were learned on the current excess sludge management of the concentrated latex industry in the south of Thailand.

Assessing ecological footprints of products from the rubber industry and palm oil mills in Thailand

Rubber and crude palm oil (CPO) are the major agricultural products of Thailand. This work aimed at evaluating the ecological footprint (EF) of ribbed smoked sheet (RSS) from cooperative rubber sheet factories, ribbed smoked sheet bale (RSSB) from large rubber sheet factories, Standard Thai Rubber (STR) from block rubber factories, concentrated latex from concentrated latex factories, and CPO of palm oil mills in Thailand. The system boundary of cradle to gate was set according to the life cycle assessment approach. The fresh latex and cup lump from rubber plantations and fresh fruit bunch from the oil palm plantations were the major inputs for the rubber factory and the palm oil mill, respectively. EFs of the selected products from high to low were STR 20 at 7.06 global hectares (gha)/tonne, RSSB at 6.87 gha/tonne, RSS at 6.78 gha/tonne, STR 5 at 6.68 gha/tonne, concentrated latex at 5.07 gha/tonne, and CPO at 4.34 gha/tonne, on average. The EF of forest for production of fresh latex, cup lump and unsmoked sheet, and fresh fruit bunch accounted for more than 92% of the total EF. The EF for processing was quite less for the products of both rubber factories and palm oil mills. The production of RSS had a high potential for reducing the EF, followed by that of concentrated latex and STR, respectively. In 2015, the total EF for the production of rubber products and CPO in Thailand was 35.2 and 30.5 million gha for the average and best observed scenarios, respectively. The alternative methods for reduction of EF should be emphasized. The policy makers should include the EF values as the indicator for supporting the expansion of rubber and oil palm industries.

GHG Emission as a Measure of Environmental Impacts in Producing Selected Natural Rubber Products

Rubber production has been taking place in Sri Lanka for more than 100 years. This study presents emission of green house gases (GHG) associated with the production of concentrated latex and crepe rubber in Sri Lanka. According to the extent of rubber plantation by districts of Sri Lanka, Kegalle, Kalutara, Ratnapura and Colombo are the major rubber growing districts. Out of these districts Kegalle, Kalutara and Colombo were selected for the study. List of rubber manufacturing industries were used to select industries. Those industries were categorised based on number of workers such as small scale, medium scale and large scale. Industries were selected from all categories proportionate to the total no of industries in the list. Based on the list of rubber factories belonging to plantation companies and three factories belonging to private companies in Sri Lanka were used to collect all activity data were collected for a year. From April 2010 to March 2011 (financial year). The agricultural activities in rubber plantation and fuel consumption for staff transportation were not taken to account. Emission of greenhouse gases associated with the production of primary rubber products (crepe rubber and centrifuge latex) are quantified as functions of activities and emission factors. Diesel uses in fresh latex transportation, electricity use, diesel use for self power generation, production of diesel for latex transportation and self power generation and waste water generation from concentrated and crepe factories were considered for GHG emission calculation. Other than that, ammonia production for concentrated latex factories and firewood use in crepe rubber factories were also considered. Total emission for the year 2010 from the production of concentrated latex is 1,339,663 Ton of CO2 Eq. and from the production of crepe rubber is 8,431,884.1 ton of CO2 Eq. The emission factors of the production of concentrated latex and crepe rubber was estimated as 55.016 and 138.123 ton CO2 Eq per ton of product respectively. Emissions are largely associated with waste water discharges and energy use. This study discusses to reduce GHG emissions from above two product production processes. Keywords: GHG, Emission, Concentrated latex, Crepe rubber

Evaluating sulfuric acid reduction, substitution, and recovery to improve environmental performance and biogas productivity in rubber latex industry

Sulfuric acid is heavily used in concentrated rubber latex factories to coagulate rubber particles in skim latex. The resulting sulfate-rich wastewater creates the onset of toxic H2S gas production in the wastewater holding ponds, causing severe corrosion to materials and community disturbance when dispersed to ambient air. This work identified and evaluated measures to reduce H2S production by minimizing sulfate concentration in the wastewater. Sulfuric acid use could be cut down by pre-removal of ammonia in the skim latex as well as a stricter manipulation of acid dosing. In search of a more benign chemical, a heat sensitive polymer was identified and tested as sulfuric acid substitute. The use of hydroxypropyl methylcellulose polymer (HPMC) changed wastewater characteristics and was found to increase biogas production approximately by 2.4 times in batch assay at the initial pH 7.0 and methane yield by 2.7 times in continuous digester operation at HRT 7 days. Finally, a resource recovery option was evaluated. The remaining H2S in the produced biogas was oxidized in the biotrickling filter to sulfuric acid that has a potential to partially supplement the fresh acid. This work demonstrated an integrated approach in waste management to improve environmental performance, safety and energy recovery in the concentrated latex industry.

Phytoremediation of Latex Effluent by Constructed Wetland Technology

The present study is an attempt to have a comparative assessment of the efficiency of aquatic weeds like<i> Typha latifolia, Eichhornia crassipes, </i><i>Pistia stratiotes</i> to treat the effluents from latex factory, in constructed wetlands. Ammonification of field latex, acid coagulation of skim latex and various chemical treatments during the production process of various products were found to be responsible for the high concentration of pollutants in this factory effluent. Phytoremediation for fifteen days by constructed wetland technology reduced the chemical oxygen demand, biochemical oxygen demand, pH, total solids of the effluent considerably.

An Application of Lean Supply Chain Management for Cost Reduction in Latex Industry

The objective of this research is to reduce the total systemwide cost of the latex industry supply chain, including three significant stakeholders, who are rubber plantation (farmer), latex factory, and glove factory. The lean concept is employed to investigate the wastes and to propose alternative methods for eliminating them. The value stream mapping technique (VSM) is used as a tool to identify non-value added activities in the supply chain. There are three main steps for this research, 1) create a supply chain model for latex industry, 2) assess the current state of the supply chain by evaluating value added (VA), non-value added (NVA) activities and the total supply chain cost, 3) move toward the future state by analyzing root causes and identifying countermeasures to eliminate wastes. The result indicates that the largest percentage of the total systemwide cost is the storage cost of raw materials and finished goods, which is accounted for 58.35%. The further research will be created forecasting technique and design collecting point field latex for reduce labor cost in supply chain. Keywords Lean Supply Chain Management, Latex Industry, Cost Reduction

Shortwave near Infrared Spectroscopy for Determination of Dry Rubber Content and Total Solids Content of Para Rubber (Hevea Brasiliensis) Latex

The objective of this research was to apply shortwave near infrared (NIR) (700–1100nm) spectroscopy to the evaluation of dry rubber content (DRC, %) and total solids content (TSC, %) in Para rubber field and concentrated latex. The spectra were obtained in transmission mode. There were 282 samples including field latex, concentrated latex and concentration adjusted concentrated latex of 171, 86 and 25 samples, respectively. The field latex had around 30% DRC and the concentrated latex had around 60% DRC. The concentration adjusted concentrated latex was in five levels which were 55%, 50%, 45%, 40% and 35% DRC. The calibration models were developed by original and pre-treated absorbance spectra using partial least square regression The pre-treatment methods were smoothing, normalisation, derivative, baseline offset, standard normal variate or multiple scatter correction. By statistical analysis, the model developed from smoothing and range normalisation pre-treated spectra in the wavelength range of 700–950 nm provided the best accuracy of prediction for DRC and the models using raw spectra in the same wavelength range gave the best results for TSC. The slope, offset, coefficient of determination ( r2), standard error of prediction ( SEP) and bias were 1.0154, −0.6286, 0.992, 1.1092% and 0.0321%, respectively, for the prediction of DRC and 1.0084, −0.2332, 0.991, 1.3611% and 0.1456%, respectively for the prediction of TSC. The best models were validated using new sets of 50 and 35 unknown samples for DRC and TSC, respectively. The models achieved an r2 of 0.988 and 0.974, SEP of 1.4296 and 2.1255, RPD of 10.0 and 6.2 and bias of −0.6191% and 0.5476% for DRC and TSC, respectively. This work showed the high accuracy of SW-NIR spectroscopy in the evaluation of TSC, the essential parameter for quality assurance and process control in the concentrated rubber latex factory. However, the accuracy for prediction of DRC was still not acceptable for the latex factory because a bias of more than 0.01% is not acceptable for it would affect the amount of money which the factory may lose or gain.

Alergia al látex. diagnóstico y aspectos terapéuticos

In the last two decades of the 20th century, latex allergy has reached epidemic proportions. Epidemiological studies demonstrate that 3-25 % of health personnel is allergic to latex. The main risk groups are health workers, machine operators in latex factories, and children with spina bifida and urogenital anomalies. From the allergenic point of view, latex contains 240 peptides but approximately 50 are able to react to IgE. Latex elongation factor Hevdl is the relevant allergen in patients with spina bifida. Prohevein (hev B6) behaves as a major allergen, since it reacts to IgE in most of the sera of patients with latex allergy. The nature of latex is complex; it is an allergenic mixture that depends on chemical, immunological and epidemiological variables. Latex proteins show strong cross reactivity with several proteins from fruit and vegetable grains such as avocado, potato, banana, tomato, chestnut, and kiwi. In vivo studies have shown that class I chitinase from avocado and chestnut behave as major allergens in allergic patients with latex-fruit syndrome. The clinical manifestations related to the use of latex products depend on the type of exposure, the amount of the allergen, and individual variability. The most useful diagnostic method is the skin prick test. Several perioperative guidelines are recommended in patients sensitized to latex as well as various alternatives to rubber gloves. An increasing number of studies describe the efficacy of etiological treatment (immunotherapy), using different guidelines and routes of administration. These preliminary data encourage the hope that in the near future immunomodulatory therapy will be available to mitigate against the latex allergy epidemic.

Recycling of natural rubber latex waste and its interaction in epoxidised natural rubber

The waste rubber formed in latex-based industries is around 10–15% of the rubber consumed. The formation of a higher percentage of waste latex rubber (WLR) in latex factories is due to the unstable nature of the latex compound and the strict specifications in the quality of latex products. These latex rejects contain about 95% rubber hydrocarbon of very high quality, which is only lightly cross-linked. These rejects, if not properly used, can create serious ecological and environmental problems. The authors have developed a cost-effective technique for the reuse of WLR in epoxidised natural rubber (ENR). The effect of powdered rejects on the curing behaviour, mechanical performance and swelling nature has been investigated. The cure characteristics such as optimum cure time, rheometric scorch time and induction time, are found to decrease with increasing concentration of latex waste filler. When the vulcanisation system is conventional, the finest size filler shows superior mechanical performance while the order of performance is reversed when the vulcanisation mode changes to efficient. The applications and limitations of several theoretical models in describing the tensile modulus of the samples have been demonstrated. A three-layer model has been used to study the migration of sulphur from ENR to the latex filler phase. The extent of sulphur migration in the case of different particle sizes of latex waste filler in two different vulcanisation systems has been analysed. The failure behaviour of the samples was analysed using scanning electron microscopy. The study shows that waste latex rubber can be used as filler in ENR economically.

Nitrogen removal in attached growth waste stabilization ponds of wastewater from a rubber factory

Nitrogen removal from wastewater from rubber factories using attached-growth waste stabilization ponds (AGWSP) was evaluated. Usually, wastewaters generated from rubber factories such as concentrated latex factories and rubber sheet factories contain a high amount of nitrogen originating from natural rubber and ammonia compounds added in the production processes. From an investigation of 3 rubber factories at Songkhla, Thailand, average concentrations of TKN, NH3-N and Org-N in raw factory wastewater were found to be 889, 578 and 311 mg/l respectively. Two series of laboratory waste treatment ponds, waste stabilization ponds (WSP) and attached-growth waste stabilization ponds were investigated to compare the efficiency of nitrogen removal from wastewater from a concentrated latex factory. The wastewater fed to the experimental units was collected from the effluent of the anaerobic treatment pond at the factory. The experiments were conducted with hydraulic retention times (HRT) of 40 and 20 days. Another experiment run with an HRT of 40 days together with 50% recirculating of effluent was also conducted. Finally, an experiment run at an HRT of 4 days was carried out in order to observe the effect of shock loading. The results revealed that TKN, NH3-N and BOD5 removal efficiencies in AGWSP were higher than in control ponds (WSP). Increased removal efficiencies were achieved which resulted from an increase in biomass on media in the pond water.