Evaluation of the effect of parameters affecting biological and physicochemical phosphate removal from wastewaters in a Multi-Soil-Layering system

 L’évacuation des eaux usées est un problème qui s’aggrave dans certaines zones rurales marocaines. Des rejets de phosphore et d’azote élevés peuvent entraîner l’eutrophisation des eaux réceptrices. Le processus biologique est l’alternative la plus adaptée aux besoins de ces zones, comme le système des filtres imbriqués (FI). Le procédé d’épuration des eaux usées en milieu rural par FI, un système innovant utilisé pour la première fois au Maroc, a été étudié en modélisant les relations entre un ensemble de facteurs environnementaux et le phosphore total éliminé, sur la base de 153 échantillonnages. Trois modèles pilotes de FI,  construites dans trois boîtes en plastique de 36 cm x 30 cm × 65 cm , ont été alimentés en continu par des eaux usées domestiques, avec un taux de charge hydraulique (HLR) de 250, 500 et 1000 l / m2/ jour. Cette étude a pour but d’étudier et de quantifier l’effet des paramètres affectant l’élimination biologique et physico-chimique du phosphore des eaux usées dans ce système, à l’aide de réseaux neuronaux (NN) et d’analyses de régression multiple (ARM). Les résultats montrent l’influence de la charge hydraulique (HLR), du potentiel hydrogène (pH), de la charge de phosphore (PL), du nitrite (NO2--N), de l’oxygène dissous (OD), de la demande biochimique d’oxygène (DBO5) et du nitrate (NO3--N) dans l’élimination du phosphore avec une contribution de 36, 16, 15, 12, 9, 7 et 6 % respectivement. Mots clés: Analyse de régression multiple, filtres imbriqués, les réseaux de neurones, Phosphore.Wastewater disposal is a serious problem in Moroccan rural area. Discharged with high levels of phosphorus and nitrogen can result in eutrophication of receiving waters. Biological processes are the most adapted alternative to the needs of these areas, such as the Multi-Soil-Layering (MSL) system. The process of rural wastewater treatment by MSL, which is an innovative system used for the first time in Morocco, was studied by modelling the relationships between a set of environmental factors and total phosphorus removed, based upon 153 sampling. Three MSL pilot plants, constructed in three 36 cm × 30 cm × 65 cm plastic boxes, were continuously fed with domestic wastewater, with different hydraulic loading rate (HLR) of 250, 500 and 1000 l/m2/day. This study was to investigate and quantify the effect of parameters affecting biological and physico-chemical phosphate removal from wastewaters in this system, using neural networks (NNs) and multiple regression analysis (MRA). The results show the influence of the hydraulic loading rate (HLR), Hydrogen potential (pH), phosphorus load (PL), nitrite (NO2--N), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD5), and the Nitrate-nitrogen (NO3–-N) in the phosphorus removal with a contribution of 36, 16, 15, 12, 9, 7 and 6 % respectively. Keywords: Multiple regression analysis, multi-soil-layering, neural networks, phosphorus removal

Evaluation of the effect of parameters affecting biological and physicochemical phosphate removal from wastewaters in a Multi-Soil-Layering system

 L’évacuation des eaux usées est un problème qui s’aggrave dans certaines zones rurales marocaines. Des rejets de phosphore et d’azote élevés peuvent entraîner l’eutrophisation des eaux réceptrices. Le processus biologique est l’alternative la plus adaptée aux besoins de ces zones, comme le système des filtres imbriqués (FI). Le procédé d’épuration des eaux usées en milieu rural par FI, un système innovant utilisé pour la première fois au Maroc, a été étudié en modélisant les relations entre un ensemble de facteurs environnementaux et le phosphore total éliminé, sur la base de 153 échantillonnages. Trois modèles pilotes de FI,  construites dans trois boîtes en plastique de 36 cm x 30 cm × 65 cm , ont été alimentés en continu par des eaux usées domestiques, avec un taux de charge hydraulique (HLR) de 250, 500 et 1000 l / m2/ jour. Cette étude a pour but d’étudier et de quantifier l’effet des paramètres affectant l’élimination biologique et physico-chimique du phosphore des eaux usées dans ce système, à l’aide de réseaux neuronaux (NN) et d’analyses de régression multiple (ARM). Les résultats montrent l’influence de la charge hydraulique (HLR), du potentiel hydrogène (pH), de la charge de phosphore (PL), du nitrite (NO2--N), de l’oxygène dissous (OD), de la demande biochimique d’oxygène (DBO5) et du nitrate (NO3--N) dans l’élimination du phosphore avec une contribution de 36, 16, 15, 12, 9, 7 et 6 % respectivement. Mots clés: Analyse de régression multiple, filtres imbriqués, les réseaux de neurones, Phosphore.Wastewater disposal is a serious problem in Moroccan rural area. Discharged with high levels of phosphorus and nitrogen can result in eutrophication of receiving waters. Biological processes are the most adapted alternative to the needs of these areas, such as the Multi-Soil-Layering (MSL) system. The process of rural wastewater treatment by MSL, which is an innovative system used for the first time in Morocco, was studied by modelling the relationships between a set of environmental factors and total phosphorus removed, based upon 153 sampling. Three MSL pilot plants, constructed in three 36 cm × 30 cm × 65 cm plastic boxes, were continuously fed with domestic wastewater, with different hydraulic loading rate (HLR) of 250, 500 and 1000 l/m2/day. This study was to investigate and quantify the effect of parameters affecting biological and physico-chemical phosphate removal from wastewaters in this system, using neural networks (NNs) and multiple regression analysis (MRA). The results show the influence of the hydraulic loading rate (HLR), Hydrogen potential (pH), phosphorus load (PL), nitrite (NO2--N), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD5), and the Nitrate-nitrogen (NO3–-N) in the phosphorus removal with a contribution of 36, 16, 15, 12, 9, 7 and 6 % respectively. Keywords: Multiple regression analysis, multi-soil-layering, neural networks, phosphorus removal

Effect of increasing inoculum ratio on energy recovery from chicken manure for better use in Egyptian agricultural farms

Abstract Background Poultry production is one of the fastest growing agricultural activities in Egypt. This activity is delivering large quantities of chicken manure. This organic waste can have a negative impact on the environment and public health in the vicinity of the Egyptian agricultural farms. In this study, we treated this organic waste by anaerobic digestion for achieving the maximum production of biogas with a high percentage of methane. For this, we investigated the different ratio of bacterial inoculum and manure chicken content. Methods Seven anaerobic mixtures with different inoculums (1:1, 1:2, 1:3, 1:4, 1:5, 1:6 and 1:7) were tested. All digesters are placed in a constant temperature 35 °C. Biogas and methane production during 50 days of incubation. Results The best ratio in terms of biogas produce is the low ratio (1:7) with a production of 73.3 Nml/gVS. But from a qualitative point of view, the largest ratio (1:1) was delivering a biogas with the highest calorific value in terms of methane content with 69.9% of biogas. Conclusions The energy valorization of chicken manure depends on the waste/inoculum ratio. The maximum biogas produced is using the lowest ratio of waste and inoculum (1:7) but the highest methane percentage in the biogas is reached by the highest of ratio (1:1). Thus, from a qualitative point of view, the high percentage of methane is obtained for the highest ratio 1:1, however, from a quantitative point of view, the largest production is obtained from the lowest ratio 1:7

Quantitative evaluation of the effect of parameters affecting biological and physicochemical phosphate removal from wastewaters in a Multi-Soil-Layering system

Wastewater disposal is a serious problem in Moroccan rural area. Discharged with high levels of phosphorus and nitrogen can result in eutrophication of receiving waters. Biological processes are the most adapted alternative to the needs of these areas, such as the Multi-Soil-Layering (MSL) system. The process of rural wastewater treatment by MSL, which is an innovative system used for the first time in Morocco, was studied by modelling the relationships between a set of environmental factors and total phosphorus removed, based upon 153 sampling. Three MSL pilot plants, constructed in three 36 cm × 30 cm × 65 cm plastic boxes, were continuously fed with domestic wastewater, with different hydraulic loading rate (HLR) of 250, 500 and 1000 l/m2/day. This study was to investigate and quantify the effect of parameters affecting biological and physico-chemical phosphate removal from wastewaters in this system, using neural networks (NNs) and multiple regression analysis (MRA). The results show the influence of the hydraulic loading rate (HLR), Hydrogen potential (pH), phosphorus load (PL), nitrite (NO2--N), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD5), and the Nitrate-nitrogen (NO3–-N) in the phosphorus removal with a contribution of 36, 16, 15, 12, 9, 7 and 6% respectively

Improving the Imazapyr Degradation by Photocatalytic Ozonation: A Comparative Study with Different Oxidative Chemical Processes

The degradation of imazapyr (C13H15N3O3), an active element in the aqueous solution of commercial herbicide, was investigated. This study was the first to evaluate in a comprehensive manner the efficiency of advanced oxidation processes for imazapyr degradation. Results showed that Imazapyr degradation is significantly affected by operational conditions such as TiO2 concentration, ozone concentration, initial concentration of imazapyr and pH. The kinetics of Imazapyr consumption was the first order with respect to Imazapyr concentration and zero order with respect to ozone concentration with a constant rate of 0.247 min−1 and 0.128 min−1 for photocatalytic ozonation and heterogeneous photocatalysis, while it was the first order with respect to Imazapyr and the first order with respect to ozone concentrations when only ozone was used with a constant rate of 0.053 mol L−1 min−1 at pH 7. The results revealed that more than 90 percent of the removal efficiency representing the elimination of imazapyr was held up to 7 μM. Further increase in the concentration of imazapyr leads to a drop in the removal efficiency, however the total imazapyr degradation was reached in 20 min utilizing photocatalytic ozonation for 5 μM of Imazapyr in the presence of 100 mg L−1 of TiO2, 10 mg L−1 of ozone at pH 7. Photocatalytic ozonation and heterogeneous photocatalysis utilizing TiO2 as a semiconductor process appeared possible and well suited for the treatment of organic contaminants such as imazapyr herbicides, although at certain dosages of pH and common time for wastewater treatment, imazapyr was not degraded with ozonation on its own. The association of two oxidation processes, ozonation and photocatalysis, has improved oxidation efficiencies for water treatment under optimal conditions, leading to the development of non-selective hydroxyl and more reactive radicals in the oxidation medium, as well as the resulting synergistic effects between photocatalysis and ozonation that react more rapidly with imazapyr herbicide

Factors Influencing Imazapyr Herbicide Removal from Wastewater Using Photocatalytic Ozonation

This study investigates the degradation of imazapyr herbicide from wastewater by photocatalytic ozonation using TiO2 as a semiconductor. Effects of operational parameters on imazapyr removal efficiency including TiO2 dosing, initial herbicide concentration and pH were also studied. Obtained results showed that more than 90% of removal efficiency representing the disappearance of imazapyr was maintained until 7 mu M in the presence of 200 mgL(-1) of UV100-TiO2. Otherwise, the degradation of imazapyr followed the first-order kinetics with a photocatalytic rate constant of 0.247 min(-1), and complete degradation was achieved within 20 min using photocatalytic ozonation for 5 mu M of Imazapyr at pH 7