Application of treated wastewater and digested sewage sludge to obtain biodiesel from Helianthus annuus L. seeds oil

Waste from wastewater treatment plants (WWTP) for Helianthus annuus L. production may be a viable solution to obtain biodiesel. This study achieved two objectives: assess the agronomical viability of waste (wastewater and sludge) from the Alcázar de San Juan WWTP in central Spain for H. annuus L. production; use H. annuus L. seeds grown in this way to obtain biodiesel. Five study plots, each measuring 6 m × 6 m (36 m²), were set up on the agricultural land near the Alcázar de San Juan WWTP. Five fertilizer treatment types were considered: drinking water, as the control; treated wastewater; 10 t ha^?1 of air-dried sewage sludge; 20 t ha^?1 of air-dried sewage sludge; 0.6 t ha^?1 of commercial inorganic fertilizer. Soil, irrigation water, sewage sludge, crop development and fatty acid composition in achenes oil were monitored. The 20 t ha^–1 dose of sewage sludge proved effective to grow H. annuus L. with similar results to those grown with a commercial fertilizer. However, precautions should be taken when irrigating with wastewater because of high salinity and nutrient deficiency. Sunflower oil was composed mostly of linoleic and oleic acid. The remaining fatty acids were linolenic, estearic, nervonic, palmitoleic, and palmitic.     

Production and characterization of biodiesel from Eriobotrya Japonica seed oil: an optimization study

Biodiesel is now-a-days recognized as a real potential alternative to petroleum-derived diesel fuel due to its number of desirable characteristics. However, its higher production cost resulting mainly due to use of costly food-grade vegetable oils as raw materials is the major barrier to its economic viability. Present work is an attempt to explore the potential of Eriobotrya japonica seed oil for the synthesis of biodiesel using alkali-catalyzed transesterification. Optimization of production parameters, namely molar ratio of alcohol to oil, amount of catalyst, reaction time and temperature, was carried out using Taguchi method. Fatty acid composition of both oil and biodiesel was determined using GC and H¹ NMR. Alcohol to oil molar ratio of 6:1, catalyst amount of 1% wt/wt, 2 h reaction time and 50 ^°C reaction temperature were found to be the optimum conditions for obtaining 94.52% biodiesel. Highest % contribution was shown by the ‘amount of catalyst’ (67.32%) followed by molar ratio of alcohol to oil (25.51%). Major fuel properties of E. japonica methyl esters produced under optimum conditions were found within the specified limits of ASTM D6751 for biodiesel, hence it may be considered a prospective substitute of petro-diesel.     

Prospect of castor oil biodiesel in Bangladesh: Process development and optimization study

In this study, castor oil (CO) has been investigated as a potential source for biodiesel production in Bangladesh. Castor oil has been extracted from the seeds by mechanical press and the Soxhlet extraction method. Maximum oil content of 55.7% has been found by the Soxhlet extraction method. The physicochemical properties such as free fatty acid (FFA) content, kinematic viscosity, saponification value, and density of the oil have been measured by different standard methods. The FFA content and viscosity have been found considerably higher such as 33.5% and 253 mm²/s, respectively. Biodiesel has been prepared using a three-step method comprising of saponification of oil followed by acidification of the soap and esterification of FFA. The overall yield of FFA from CO is found to be around 89.2%. The final step is esterification that produces fatty acid methyl ester (FAME) and a maximum 97.4% conversion of FFA to biodiesel has been observed. The effect of the oil to methanol molar ratio, catalyst concentration, reaction temperature, and time has been investigated for esterification reaction and optimized using the response surface methodology. ¹H NMR of crude castor oil and castor oil methyl ester (COME) was studied and analyzed that confirms the complete conversion of castor oil to biodiesel. Finally, the biodiesel, produced under optimum conditions, was characterized using the various standard method and found comparable with petro-diesel and biodiesel standard.     

Molasses-based growth and lipid production by Chlorella pyrenoidosa: A potential feedstock for biodiesel

Biodiesel provides a feasible solution to the twin crisis of energy security and environmental concerns prevalent today, and it can be extracted from conventional oil crops as well as microalgae. However, lipid productivity in case of microalgae is much higher and has several advantages as compared with crop plants, so it is a better feedstock for biodiesel. In case of Chlorella pyrenoidosa, the heterotrophic cultured cells were found to be better in terms of lipid production, and ultimately biodiesel production, but the bottleneck is that in this mode glucose is used to feed the cells, which amounts to almost 80% of the total cost of biodiesel production. The purpose of this study is to evaluate and highlight the feasibility of using the industrially cheap cane molasses as a carbon source in place of glucose for a large-scale, low-cost lipid production of Chlorella pyrenoidosa. When treated molasses was used as a carbon source instead of glucose, the biomass sharply increases from 0.89 to 1.22 g L^–1. On the other hand, the total lipid content increases from 0.27 to 0.66 g g^–1. The specific growth rate and yield was higher in treated molasses as compared with that in glucose-supplemented. A mathematical model was also developed based on logistic, Luedeking–Piret, and Luedeking-Piret-like equations. Model predictions were in satisfactory agreement with the measured data, and the mode of lipid production was growth-associated.     

高级催化氧化法处理高含盐废水研究

针对风城油田生产废水高盐、高温、高矿化度、可生化性差等水质特性,现场采用“混凝沉降+高级催化氧化”工艺,处理后出水达到《污水综合排放标准》GB8978中二级排放标准。混凝沉降阶段COD去除率为36~49%,挥发酚去除率为11~21%,石油类去除率为42~69%;催化氧化阶段COD去除率为20%~40%,挥发酚去除率为69%~73%,石油类去除率为16%~20%。     

Resource utilization of wasted black pulping liquor for biodiesel production by Scenedesmus obliquus

The possibility of application of black liquor for oil-riched algae cultivation is inspected. The results show that after ligin removal and enzymatic hydrolysis, the hydrolysate of black liquor contained 9.18 g L^?1 of reducing sugar. When the hydrolysate was used for Scenedesmus obliquus (S. obliquus) cultivation, a 1.23 g L^?1, 24.52%, and 23.20 mg L^?1d^?1 was obtained for growth yield, oil content, and the lipid productivity, seperately. The hemicellulose was extracted from black liquor and hydrolyzed. With addition of 3 g L^?1 yeast extract, the growth yield of S. obliquus in hemicellulose hydrolysate increased to 2.7 g L^?1, an increase of 26.8% than that of in glucose medium, oil content was 25.7% and the final lipid productivity reached 53.37 mg L^?1d^?1. The results indicate that black liquor can not be directly used by microalgae, but with approprate treatment, the carbohydrate of it could be recovered and uitilized for the oil production from microalgae.     

O2-Fenton试剂处理对氨基苯磺酸废水的探讨

利用由O2和Fenton试剂组成的类Fenton系统处理对氨基苯磺酸废水,取得了很好的降解效果.当FeSO4(10g/L)投加量为1.2mL、H2O2(3%)投加量为3mL时,COD去除率可达到70%.     

Production of soybean ethanol-based biodiesel using CaO heterogeneous catalysts promoted by Zn,K and Mg

This article focuses on the optimization of the production of fatty acid ethyl esters from soybean oil using CaO-based heterogeneous catalysts. Three different catalytic promoters were evaluated: Magnesium, zinc, and potassium. The reaction has evaluated the promoter content (promoter to calcium molar ratio), catalyst load, alcohol to oil molar ratio, and temperature. Response surface methodology (RSM) was used to evaluate the influence of each variable on the yield of biodiesel. The addition of K₂O or MgO in the catalyst has enhanced the yield in fatty acid ethyl esters, while the use of ZnO as a promoter was not successful.     

Removal of organic pollutants and nutrients from olive mill wastewater by a sand filter

The aim of this work was to examine the performance of a sand filter in treating modern olive mill (OMW) effluents after dilution with domestic wastewater on a one-to-one basis. The experimental pilot consisted of a column of opaque PVC, and the sand filter was filled with 50 cm of sand and 10 cm of gravel in the top and the bottom of the filter. The alimentation (4 cm/day) was done sequentially following a 1 day wet/3 days dry cycle. The OMW effluent was very acidic with a pH of 4.12, and had high concentrations of phenolic compounds (7.2 g/L) and total chemical oxygen demand (65 g/L). The percolation of the diluted OMW through the sand filters caused an increase in pH from 4.84 to 8.25 and a 90% removal of total suspended solids. The sand filter treatment also led to important reductions in organic matter (90% of total COD, 83% of dissolved COD and 92% of phenolic compounds) and nutrients (91% of Kjeldahl-nitrogen, 97% of ammonia-nitrogen, 99% of nitrate-nitrogen and 99% of phosphates). The flow rate became very low indicating clogging of the sand pores after 10 weeks. HPLC analysis of the diluted OMW before and after passage through the sand filter showed an important reduction in the toxic monomeric compounds after the treatment.     

A process model to estimate the cost of industrial scale biodiesel production from waste cooking oil by supercritical transesterification

This paper describes the conceptual design of a production process in which waste cooking oil is converted via supercritical transesterification with methanol to methyl esters (biodiesel).Since waste cooking oil contains water and free fatty acids, supercritical transesterification offers great advantage to eliminate the pre-treatment capital and operating cost.A supercritical transesterification process for biodiesel continuous production from waste cooking oil has been studied for three plant capacities (125,000; 80,000 and 8000 tonnes biodiesel/year). It can be concluded that biodiesel by supercritical transesterification can be scaled up resulting high purity of methyl esters (99.8%) and almost pure glycerol (96.4%) attained as by-product.The economic assessment of the biodiesel plant shows that biodiesel can be sold at US$ 0.17/l (125,000 tonnes/year), US$ 0.24/l (80,000 tonnes/year) and US$ 0.52/l for the smallest capacity (8000 tonnes/year).The sensitive key factors for the economic feasibility of the plant are: raw material price, plant capacity, glycerol price and capital cost.Overall conclusion is that the process can compete with the existing alkali and acid catalyzed processes.Especially for the conversion of waste cooking oil to biodiesel, the supercritical process is an interesting technical and economical alternative.     

Experimental evaluation of the catalytic efficiency of calcium based natural and modified catalyst for biodiesel synthesis

Transesterification of a mixture of vegetable oils with methanol using metal oxide catalysts derived from snail shell (SS) for biodiesel production was investigated. The metal oxides obtained from calcined snail shells in the temperature range of 650°–950 °C and modified by loading different potassium salts were used as a catalyst in the process. The catalysts were characterized by FT-IR, XRD, SEM-EDS, XPS and TGA. Catalytic activities of developed catalysts were also tested by Hammet indicator method and ion exchange method. The best calcination conditions were observed at 850°C for 4 hours based on biodiesel yield. The KF loaded snail shell gave highest biodiesel yield of 98 ± 1% in a batch reactor with highest basicity (15.9 mmoles/g) and basic strength measured by Hammet method. The optimized reaction conditions were: reaction temperature 65°C, reaction time 3 hours, methanol to oil molar ratio 9:1 and catalyst concentration 3wt%. Leaching and reusability tests confirm the stability of the catalyst as it encounters only 3% of leaching and small changes in catalytic activity up to five runs in terms of biodiesel yield.     

Investigation effect of hydrogen addition on the performance and exhaust emissions of Pongamia pinnata biodiesel fueled compression ignition engine

In the recent decades, the energy demand for transport and industrial sector has increased considerably. Fossil fuels which were the major fuel source for decades are no more sustainable. Biodiesel is an efficient alternative compared to depleting fossil fuels. The prospect of biodiesel as the best alternative fuel is a reliable source compared to depleting fossil fuels. Hydrogen is also considered as an attractive alternative fuel producing low emission with improved engine performance. This paper investigates the performance and emission characteristics of a single cylinder compression ignition engine using hydrogen as an inducted fuel and biodiesel, aka Pongamia pinnata as injected fuel. The experiments are conducted for different quantities of hydrogen induction through the intake manifold in order to improve the performance of the engine. The performance parameters such as brake thermal efficiency, brake specific fuel consumption, exhaust temperature and emission quantities like HC, NO_X, CO, CO₂ of biodiesel fueled CI engine with variable mass flow rate of hydrogen are investigated. The performances of biodiesel combined with hydrogen at varying mass flow rates are also compared. The 10 LPM hydrogen induction with biodiesel provided 0.33% increase of brake thermal efficiency compared with diesel and increase of 3.24% to biodiesel at 80% loading conditions. The emission of HC decreased by 13 ppm, CO decreased by 0.02% by volume and CO₂ decreased by 3.8% by volume for biodiesel with induction of hydrogen at 10 LPM to that of neat biodiesel for 80% load conditions.     

Preliminary study of physico-chemical treatment options for hospital wastewater

Hospital effluents are loaded with pathogenic microorganisms, partially metabolized pharmaceutical substances, radioactive elements, and other toxic substances. Such effluents if not treated properly can damage the natural environment and create a biological imbalance. This paper points out the areas of concern for hospital wastewater disposal and reports the findings of a limited physico-chemical study of treatment options for hospital effluents conducted at Christian Medical College and Hospital, Vellore, Tamil Nadu. The effluent collected was checked for conventional parameters and subjected to coagulation experiments. The raw and settled effluents were coagulated with FeCl(3), filtered and disinfected. Physico-chemical treatment seems to be an attractive option for the cost-effective disposal of hospital effluents. The results of this study call for further detailed study in this area.     

Ingestion and egestion of microplastic by aquatic insects in Egypt wastewater

Microplastics (MPs) are frequently regarded as environmental and biota contaminants. Yet, research on the accumulation of MPs in living entities, particularly aquatic insects that serve as food resources in the aquatic food chain, is limited. This study to investigate the accumulation of MPs in aquatic insects from water and sediment in an Egyptian wastewater basin. Four typical freshwater insect groups were used. The highest MP load per gram wet weight was reported by collector-gatherers (Chironomus sp. and Hydrophilus sp.), followed by collector-filterers (Culex sp.) with the second highest MP load. However, Predators (Aeshna sp.) had the lowest values. Also, the present results showed a reduction in the number of MPs in all insect taxa tested after a 24 h depuration time, with differences in the observed egestion ability. The mean number of MPs per individual significantly reduced after 24 h in both Chironomus sp. and Culex sp. larvae, where 53% and 40% of MPs particles were ejected from them, respectively. However, the ability of MP egestion decreases in Aeshna sp. nymph (25%), and the lowest proportion of ejection was observed in Hydrophilus sp. adults (9%). Polyethylene terephthalate fibers were the most abundant type of MP in both sediment and water, followed by fragments (polyethylene and polypropylene). Yet, only polyester fibers were detected in the various insect species. The average length of fibers in the various insects was somewhat shorter than in the surrounding environment. The current study reveals that MP ingestion by aquatic insects is not always related to levels of pollution in the environment, since other factors such as feeding strategies may play a role in MP ingestion. Based on these observations, further studies should be carried out on studies on toxicological impacts of MPs on freshwater/aquatic biota.     

Regeneration of industrial district wastewater using a combination of Fenton process and ion exchange—A case study

Regeneration studies of wastewater effluent from an organized industrial district (OID) for possible reuse in textile industry as process water was investigated. Advanced treatment methods including Fenton process, polyaluminium chloride (PAC) coagulation and ion exchange were applied on OID effluent. In Fenton process removal efficiencies for suspended solids (SS), chemical oxygen demand (COD), SAC₄₃₆ (spectral absorption coefficient), SAC₅₂₅ and SAC₆₂₀ were determined 61%, 36%, 35%, 49% and 67%, respectively. After Fenton process, wastewater samples were coagulated with PAC. Optimum removal efficiencies for SS, COD, Fe ion, SAC₄₃₆, SAC₅₂₅ and SAC₆₂₀ were determined 83%, 18%, 93%, 32%, 36% and 58%, respectively. Ion exchange experiments were conducted on chemically coagulated wastewater samples to improve the quality of wastewater. Optimum dosage of resins was determined. The experiments revealed that 1:1 resin ratio (20 mL H-type resin:20 mL OH-type resin) gave the best removal rates for the parameters considered in this study. Study results indicated that quality of the wastewater was suitable for the process water characteristics of textile industry and unit wastewater treatment cost was determined as 2.54 €/m³.     

A comparative analysis of methods to represent uncertainty in estimating the cost of constructing wastewater treatment plants

Prediction of construction cost of wastewater treatment facilities could be influential for the economic feasibility of various levels of water pollution control programs. However, construction cost estimation is difficult to precisely evaluate in an uncertain environment and measured quantities are always burdened with different types of cost structures. Therefore, an understanding of the previous development of wastewater treatment plants and of the related construction cost structures of those facilities becomes essential for dealing with an effective regional water pollution control program. But deviations between the observed values and the estimated values are supposed to be due to measurement errors only in the conventional regression models. The inherent uncertainties of the underlying cost structure, where the human estimation is influential, are rarely explored. This paper is designed to recast a well-known problem of construction cost estimation for both domestic and industrial wastewater treatment plants via a comparative framework. Comparisons were made for three technologies of regression analyses, including the conventional least squares regression method, the fuzzy linear regression method, and the newly derived fuzzy goal regression method. The case study, incorporating a complete database with 48 domestic wastewater treatment plants and 29 industrial wastewater treatment plants being collected in Taiwan, implements such a cost estimation procedure in an uncertain environment. Given that the fuzzy structure in regression estimation may account for the inherent human complexity in cost estimation, the fuzzy goal regression method does exhibit more robust results in terms of some criteria. Moderate economy of scale exists in constructing both the domestic and industrial wastewater treatment plants. Findings indicate that the optimal size of a domestic wastewater treatment plant is approximately equivalent to 15,000 m3/day (CMD) and higher in Taiwan. Yet the optimal size of an industrial wastewater treatment plant could fall in between 6000 CMD and 20,000 CMD.     

黄药废水处理的研究现状及展望

黄药是浮选金属硫化矿物应用最广、最有效的捕收剂,但其在选矿废水中的残留会对环境造成严重污染。黄药废水净化排放及回水利用不仅对环境有利,且符合选厂经济利益。本文主要介绍了近年来常用的黄药废水净化处理方法,并对未来黄药废水处理方向进行了展望,以其对黄药选矿废水的治理提供一定的参考价值。     

Total site: wastewater minimization: Wastewater reuse and regeneration reuse

Analysis of technological wastewater streams in a refinery and petrochemical complex was carried out. Wastewater flowrates, temperatures, pH and pollutant contents were measured. Regarding the characteristics of the individual waters, possible connections between water outflows from the processes or process units and potential water consumers were determined. Possibilities to reduce the flowrate of technological wastewater with wastewater reuse or preliminary regeneration and reuse were found. The consumption of fresh water could be lowered by 11.2 m³/h, reducing the treatment system load and prolonging its residence time by 7%. The payback period for the changes proposed in the petrochemical plants is 6 months with annual savings of US$27 630. The payback period for the changes proposed in the refinery is 11 days with annual savings of US$15 500.     

生物工程在废水净化中的应用及发展趋势

水污染问题是环境保护领域中重要的问题之一,如何高效的利用生物工程技术来解决这一问题已成为环保界普遍重视的问题。本文总结了近年来生物工程在废水净化中的应用现状,并对当前废水净化中生物工程的发展趋势进行了探讨。     

Treatment of domestic wastewater using an anaerobic baffled reactor followed by a duckweed pond for agricultural purposes

The treatment and reuse of domestic wastewater using an anaerobic baffled reactor (ABR) followed by a duckweed pond (DWP) were the main theme of the present study. The ABR was fed continuously with domestic wastewater at four HRTs ranging from 8 to 24 h and corresponds to organic loading rates ranging from 0.67 to 2.1 kg COD/m³/day. The ABR effluent was fed to a DWP operating at 10 and 15 days. The performance of the ABR at the four HRTs gave satisfactory results. Chemical oxygen demand (COD) removal was between 68 and 82%. Fecal coliform removal was between 1 to 2 logs. The 12- and 18-h hydraulic retention times (HRTs) gave close results, as indication of the possible selection of the 12-h HRT as the optimum operation for the ABR based on economic advantage. The ABR compartmentalized structure gave results higher than those produced by the one-stage digester and similar to those produced by the two-phase anaerobic digestion process. Duckweed ponds as post-treatment operated at 10 days and 15 days gave the best results at 15-day HRT, where it was possible to remove 73.4% of nitrogen and 65% of phosphorus and produce protein-rich dry duckweed of 105 kg/ha/day on average. The removal of fecal coliform (FC) in duckweed ponds was 3–4 logs. The final treated domestic sewage characteristics proved its compliance with the Egyptian standards for reuse in restricted irrigation.