Decrease In COD Research Articles

Reduksi Cod Dan Bod Air Limbah Domestik dengan Konsep Taman Constructed Wetland

Domestic wastewater is wastewater that comes from the activities of human daily life related to water use. If the wastewater can polute the receiving water such as river, if it is not treated before being discharged. This study aimed to determine the effectiveness and effect of the retention time of the garden with the concept of constructed wetland on the reduction of BOD and COD in domestic wastewater in terms of removal efficiency. The plants selected in this study were Kana plants and Kayu Apu plants, with a continuous circulation system. The variable retention time of wastewater in a garden reactor are 1, 2, 3, 4, 5, 6 and 7 days. The decrease in COD and BOD concentrations was analyzed by comparing COD and BOD before and after the study, as well as the effect of retention time on the effectiveness of COD and BOD reduction in gardens. The residence time did not significantly affect the decrease in the concentration of COD and BOD parameters, where as the highest percentage of COD and BOD reduction efficiency occurred on day 1 of 86% for COD and 84% for BOD.

Experimental and kinetic studies on co-digestion of agrifood and sewage sludge for biogas production

The objective of the present work was to investigate the influence of co-digestion of agricultural waste, food and kitchen waste and municipal solid waste with animal manure for enhanced biogas production. Cow dung has been used for the generation of biogas, but complete depolymerization is not obtained till now. So, it is codigested with other substrates to increase the depolymerization of substrates. So, co-digestion of selected substrates withcow dung has been performed. Results show that co-digestion of cow-dung with lignocellulosic biomass is good for the enhancement of bio-energy production. This has been suggested by a decrease in COD is 42.66%, 28.42%, 41.46%, 52.74%, 65.21% and 21.09% for cow dung slurry, a combination of cow dung with vegetable waste, kitchen waste, rice straw, wheat straw and municipal waste, respectively. The maximum decrease in TOC of 51.28% and 41.18% in wheat straw and rice straw sample, respectively, suggests the highest biodegradability.

High-expression and characterization of a novel serine protease from Ornithinibacillus caprae L9T with eco-friendly applications.

In the current work, a novel thermophilic serine protease gene (P3862) from Ornithinibacillus caprae L9T was functionally expressed in Bacillus subtilis SCK6. The monomeric enzyme of about 29 kDa was purified to homogeneity with 43.91% of recovery and 2.81-folds of purification. Characterization of the purified protease revealed the optimum activity at pH 7 and 65 °C. The protease exhibited excellent activity and stability in the presence of Na+, Mg2+, Ca2+, ethanediol, n-hexane, Tween-20, Tween-80 and Triton X-100. P3862 displayed favorable caseinolytic activity, moderate keratinolytic activity but no collagenolytic activity. Besides, the homology model of P3862 possessed a globular configuration and characteristic of α/β hydrolase fold, and displayed stable interactions with casein, glycoprotein and keratin rather than collagen. Moreover, the crude enzyme could completely dehair goatskin within 6 h, resulting in decrease in BOD5, COD and TSS loads by 72.86, 74.07, and 73.79%, respectively, as compared with Na2S treatment. Biocatalytic applications revealed that it could effectively remove egg-stains from fabrics at 37 °C for 30 min with low supplementation (300 U/mL), and was able to degrade the feathers of duck and chicken. Overall, these outstanding properties make P3862 valuable in the development of environmentally friendly biotechnologies .

Effect of Dolomite Addition on Fly Ash Based Ceramic Membrane to Reduce COD and BOD of Liquid Waste

Ceramic membrane technology plays an essential role in separation fields such as wastewater treatment. Fly ash as a membrane material has proven to be very effective for many separation processes, including water and air purification, as well as industrial and environmental resource recovery. This study aims to develop a microfiltration ceramic membrane based on fly ash with the addition of dolomite. The synthesized ceramic membranes were then characterized using XRD, SEM, and TGA. Ceramic membranes are used to reduce COD and BOD levels in tofu industrial wastewater. The results showed that the value of membrane porosity tends to increase with the addition of dolomite 0% (D0) to 30% (D30). The increase in the porosity value in the membrane was followed by a decrease in the average pore size, namely 1.6994 m at D0 and 1.1730 m at D30. The membrane with 30% dolomite composition has the best mechanical properties with a compressive strength of 35.29 MPa and superior thermal resistance. This is very beneficial for the use of membranes in the long term. Meanwhile, the membrane filtration ability and the ability of the membrane to reduce COD and BOD levels of waste increased with the addition of dolomite from 0% to 30%. However, the decrease in COD and BOD was smaller in the membrane with 45% dolomite. D30 membrane can reduce COD 80% and BOD up to 71.44%. D30 membrane is the most effective fly ash and dolomite composition in forming pores on the membrane with the best COD and BOD reduction performance.

Pengaruh Berat Karbon Aktif Kulit Jagung terhadap Penurunan COD (Chemical Oxygen Demand) Limbah Cair Industri Batik

Background: The batik industry produces chemical waste with a COD value of 1918 mg/l; (above the safe threshold of 150 mg/l). One of the wastewater treatment methods is using activated carbon, including corn husks. This study aims to determine the effect of the weight of corn husk activated carbon on the reduction of COD in batik industrial wastewater. Methods: A quasi-experimental study with a non-randomized pretest-posttest control group design using liquid waste from one of the batik industries in Rejomulyo Village, East Semarang District. This experiment applied five weight variations of corn husk activated carbon, namely 10, 20, 30, 40 and 50 grams with 4 repetitions, and 4 control samples. The effect of the treatment was observed in 50 minutes. The observations were analyzed using the Kruskal-Wallis statistical test. Results: The range and mean COD values before and after treatment were 3174.32 -5136.43 mg/l, and 584.29 - 1049.20 mg/l, respectively. The decrease in COD according to treatment ranged from 80.83% to 84.76%, while in the control group it was only 2.90%. There was an effect of the weight of corn husk activated carbon to decrease COD of batik industrial wastewater (p = 0.015), and there was an effect of the weight of corn husk activated carbon to decrease COD of batik industrial wastewater between control group and treatment group (p = 0.021). Conclusion: Corn husk activated carbon has a high potential to reduce the COD of chemical waste in the batik industry.

Study of the oxidative degradation of industrial laundry effluent from jeans by chromatography

Textile industries activities can positively affect a city’s economy. However, those industries require a great deal of water and sheds high organic load into water bodies, causing a considerate environmental impact. As potential pollutant substances, the dye’s presence in textile effluents are recalcitrant and can change the chemical and physical properties. It also resists conventional treatments. The treatment based on advanced oxidation processes presents to be efficient on dye’s degradation, but it may generate secondary toxic compounds, therefore is necessary to use techniques to evaluate its toxicity after the treatment. This study evaluated a laundry effluent, both before and after the treatment using the photo - Fenton processes. Applying liquid chromatography, results have shown that the dye's degradation was higher than 90% and a COD decrease to 73%.

Pengaruh Kecepatan Pengadukan dan Jarak Elekroda terhadap Penurunan Kadar COD dan TSS pada Limbah Batik Menggunakan Metode Elektrokoagulasi

The existence of the textile industry, especially in batik production in the region, will certainly provide benefits to the area, because it can absorb labor from the area. However, where there are advantages, there will also be disadvantages, as is the case in this textile factory where the liquid waste produced has a negative impact on the environment. This liquid waste comes from the washing and coloring process which contains dyes, heavy metals, and high salt concentrations. This study examines batik waste from a textile factory using the electrocoagulation method with aluminum electrodes. Research on batik wastewater treatment has been carried out. The results of this study prove that the electrode distance and stirring speed variables affect the COD reduction efficiency and TSS reduction in batik waste. In general, the higher the stirring speed and the closer the electrode spacing, the higher the TSS and COD reduction efficiency. There is an optimal point for stirring speed, where the highest reduction in TSS and COD efficiency is obtained at a stirring speed of 200 rpm. From the variables studied, the optimal value for both variables was obtained, namely at the electrode distance of 1.6 and at a stirring speed of 200 rpm, with the result that the efficiency value obtained was a decrease in COD of 89.39% and a decrease in TSS of 90.45 %.

Pengaruh Kecepatan Pengadukan dan Jarak Elekroda terhadap Penurunan Kadar COD dan TSS pada Limbah Batik Menggunakan Metode Elektrokoagulasi

The existence of the textile industry, especially in batik production in the region, will certainly provide benefits to the area, because it can absorb labor from the area. However, where there are advantages, there will also be disadvantages, as is the case in this textile factory where the liquid waste produced has a negative impact on the environment. This liquid waste comes from the washing and coloring process which contains dyes, heavy metals, and high salt concentrations. This study examines batik waste from a textile factory using the electrocoagulation method with aluminum electrodes. Research on batik wastewater treatment has been carried out. The results of this study prove that the electrode distance and stirring speed variables affect the COD reduction efficiency and TSS reduction in batik waste. In general, the higher the stirring speed and the closer the electrode spacing, the higher the TSS and COD reduction efficiency. There is an optimal point for stirring speed, where the highest reduction in TSS and COD efficiency is obtained at a stirring speed of 200 rpm. From the variables studied, the optimal value for both variables was obtained, namely at the electrode distance of 1.6 and at a stirring speed of 200 rpm, with the result that the efficiency value obtained was a decrease in COD of 89.39% and a decrease in TSS of 90.45 %.

Comparison of wastewater treatment in oil and gas industry using conventional methods (chemical, physical and biological)

The oil and gas industry consumes tons of water, and the water produced from this industry contains harmful substances such as petroleum products and heavy metals that negatively affect humans and the environment. The objective of this research is to know the efficiency of the conventional wastewater treatment technologies (chemical by adding Alum, biological with aeration, and physical by filtration) to treat oily wastewater and the effect of the quantity of Alum on the treatment efficiency by using jar test and laboratory analysis beside modify the system to reuse the treated water in various activities. The treatment results showed a decrease of COD by 27%, BOD by 26.5%, oil and grease by 55%, and heavy metals by 95%, and the final results are compatible with the Egyptian standards. It is found that the optimum alum quantity that can be used is 15 mg/L which can remove 48% of oil and grease. Despite the simplicity and low cost of conventional methods for industrial wastewater treatment compared to advanced methods, they still give acceptable results. Reusing the treated water and sludge saves money, encouraging many industries to use it instead of discharging it.

Improving the ecological safety of potato chips production by devising a method for wastewater treatment and recycling

The study deals with determining the effectiveness of mechanical and physical and chemical methods for the treatment of wastewater of potato chips enterprises. It was established that the wastewater that is formed at different stages of production differ in composition. Wastewater after washing and peeling potatoes is contaminated mainly with suspended soil substances of about 500 mg/l, which are not settled, and also has soluble organic substances with a value of COD of about 1,000 mg/l. It was found that the use of coagulation-flocculation treatment makes it possible to get clear water suitable for reuse for washing potatoes. Coagulant – aluminum sulfate in the amount of 250 mg/l turned out to be effective to destroy the stability of the dispersed system. To intensify the sedimentation of coagulated flakes of suspended particles, non-ionogenic flocculant, which is recommended to be dosed after the introduction of coagulant in the amount of 2.5 ml/l, was selected. Analysis of clarified water indicates a decrease in the concentration of suspended particles up to 26 mg/l and a decrease in COD and BOD5 to values of 262 mg/l and 176 mg/l, respectively. The completed studies made it possible to propose a circuit of treatment of wastewater after washing potatoes, which consists of pre-filtering, reagent treatment, water clarification, and sediment dehydration. This circuit makes it possible to intensively clean the water to the standards of its discharge into the sewage network. However, additional disinfection of water with oxidizers, for example, ozone, was proposed for the reuse of clarified water to wash vegetables at an enterprise itself. The use of the proposed circuit of intensive water treatment will allow increasing the environmental safety of the production of potato chips by preventing environmental contamination through reducing the volume of tap water consumption

Engineering TiO2 supported CTAB modified bentonite for treatment of refinery wastewater through simultaneous photocatalytic oxidation and adsorption

This study reports the removal of hydrocarbon pollutants from petroleum refinery wastewater by simultaneous photo-catalytic oxidation and adsorption using TiO2 loaded on Cetyl-trimethyl Ammonium bromide modified Bentonite clay (TiO2/CTAB-Bt). The synthesized CTAB-Bt and hybrid TiO2/CTAB-Bt were characterized by XRD, SEM, EDX, and FTIR techniques. The adsorption efficiency of CTAB-Bt was investigated using model refinery wastewater containing phenol, benzene, toluene, and naphthalene (100 ppm each). Under the optimum conditions of 0.8 g/100 mL CTAB-Bt adsorbent dosage, 40 °C, and 120 min contact time, maximum adsorption of hydrocarbons (94%) was attained. The adsorption followed pseudo-first-order kinetics and best fitted with the Langmuir isotherm model. Enthalpy (ΔH°), Gibbs free energy (ΔG°) and entropy (ΔS°) data of the system revealed that the adsorption process was endothermic, spontaneous and feasible. Through simultaneous photocatalytic oxidation under UV light irradiation and adsorption using TiO2/CTAB-Bt, the maximum removal (93%) of hydrocarbons from the model wastewater was achieved under milder conditions of 1100 mg/500 mL of TiO2/CTAB-Bt, 30 °C temperature and 60 min contact time. In the case of real refinery wastewater, CTAB-Bt realized 92% decrease in the COD via adsorption at 40 °C in 120 min, while simultaneous photocatalytic oxidation and adsorption achieved 94% decrease in COD at 30 °C in 60 min. The reaction products of photocatalytic oxidation of refinery wastewater were analyzed by GC–MS analysis. This study reports a new and interesting strategy of photocatalytic oxidation and adsorption for the remediation of hydrocarbon pollutants from refinery wastewater using CTAB-Bt.

PEMANFAATAN ARANG AKTIF KULIT JENGKOL (Pithecellobium lobatum) SEBAGAI ADSORBEN DALAM MENYISIHKAN KADAR COD DAN TSS PADA LIMBAH CAIR TAHU

Tofu liquid waste comes from the washing process, boiling, and printing on tofu production. Tofu liquid waste is usually directly discharged into rivers or sewers which can have a negative impact on the environment. Tofu wastewater treatment with activated charcoal adsorption methods can reduce the concentration of pollutants contained in the waste. This research was conducted to determine the effect of variations in stirring speed in the removal of COD and TSS levels in tofu liquid waste. The adsorbent used in this study was activated charcoal from the skin of jengkol (Pithecellobium lobatum) carbonized at 350ºC which was then activated using 1M HCL. The adsorption process in this study used a mass of 2 g of activated charcoal; 4 g, 6 g and 8 g and stirring speed 60 rpm and 120 rpm. The initial concentrations of COD and TSS were 5140 mg/L and 605 mg/L. The results of the research that have been carried out show that the stirring speed and mass of the adsorbent affect the levels of COD and TSS as well as the effectiveness and adsorption capacity. A significant decrease in COD and TSS levels occurred in the treatment using 8 g of activated charcoal and a stirring speed of 120 rpm. The COD value obtained was 1137 mg/L, TSS was 103 mg/L and the efficiency value obtained was COD of 77.88% and TSS of 82.98%.

Integrated ecosystem impacts of climate change and eutrophication on main Baltic fishery resources

The Baltic Sea is a heavily impacted ecosystem with multiple pressures acting simultaneously. In order to quantify ecosystem impacts of integrated climate change and eutrophication pressures under constant high fishing pressure, and to support decision-making and policies in generating environmental and economic sustainable systems, the Baltic Atlantis holistic and mechanistic ecosystem model was applied. The overall aim was to run scenarios of separate and integrated impacts of climate and riverine nutrient load changes, taking into account the interactions of the full food web in the entire Baltic Sea. This was done to identify which of those two pressures will likely dominate the future of the Baltic Sea ecosystem, and to test effects of different riverine nutrient forcing sources as well as the Baltic Atlantis functions in relation to hydrographic spawning thresholds. By integrating the hydrography, the biology covering all trophic levels of the food web, and multiple pressures, i.e. eutrophication, climate change and fishery, we were able to evaluate relative impacts of 3 climate scenarios and 3 nutrient load scenarios, using two sources of nutrient forcing and predict likely trends in ecosystem effects. With focus on major fish stocks, our model, with its assumptions, indicated that nutrient loads are the main driver of the changes in the ecosystem as long as the hydrographic thresholds for spawning are not reached. If the thresholds are reached for the Baltic cod, climate change impact will become most important. Furthermore, higher nutrient loads resulted in cod decrease, and increase in sprat and herring. This effect is amplified by stronger climate change. Overall, it is of crucial importance for the future of the Baltic Sea fisheries and stocks that potential impacts are considered both separate and integrated in a dynamic ecosystem-based management approach.

Total and Metabolically Active Microbial Community of Aerobic Granular Sludge Systems Operated in Sequential Batch Reactors: Effect of Pharmaceutical Compounds.

Two aerobic granular sludge (AGS) sequential batch reactors were operated at a mild (15 °C) temperature for 180 days. One of those bioreactors was exposed to a mixture of diclofenac, naproxen, trimethoprim, and carbamazepine. The AGS system, operating under pressure from emerging contaminants, showed a decrease in COD, BOD5, and TN removal capacity, mainly observed during the first 100 days, in comparison with the removal ratios detected in the control bioreactor. After an acclimatisation period, the removal reached high-quality effluent for COD and TN, close to 95% and 90%, respectively. In the steady-state period, trimethoprim and diclofenac were successfully removed with values around 50%, while carbamazepine and naproxen were more recalcitrant. The dominant bacterial OTUs were affected by the presence of a mixture of pharmaceutical compounds, under which the dominant phylotypes changed to OTUs classified among the Pseudomonas, Gemmobacter, and Comamonadaceae. The RT-qPCR and qPCR results showed the deep effects of pharmaceutical compounds on the number of copies of target genes. Statistical analyses allowed for linking the total and active microbial communities with the physico-chemical performance, describing the effects of pharmaceutical compounds in pollution degradation, as well as the successful adaptation of the system to treat wastewater in the presence of toxic compounds.

Pengolahan Limbah Cair Industri Minyak Sawit Menggunakan Reaktor Listrik Plat Kolom Secara Kontinu serta dengan Penambahan PAC

Palm oil industrial waste contains various dissolved compounds in the form of short fibers, hemicellulose, and their derivatives, proteins, free organic acids, a mixture of minerals and organic pigments such as anthocyanins, carotenes, polyphenols, lignins and tannins. Organic compounds in this waste will cause problems such as an increase in TSS, COD values which can pollute the environment. The electrocoagulation method has the potential to reduce TSS, TDS, COD content and neutralize pH. The purpose of this study was to determine the effect and optimum conditions of the electrocoagulation process with variations in flow rate, voltage, spacing between plates and the addition of poly aluminum chloride (PAC) coagulants to decrease TSS, COD and pH parameters so that they meet the quality standards of waste in Permen LH. No. 5/2014. The method used is a continuous electrocoagulation process using an aluminum catalyst and the addition of PAC. The variables used in this study were the stress variable (24; 26; 28 V) and the variable flow rate velocity (0.3; 1,2; 2.5 L / min) and the variation of the spacing between the plates (2, 3, 4 cm). The results of this study found that the optimum conditions were obtained at a voltage of 28 volts and a flow rate of 0.3, and a distance between the plates of 2 cm and the addition of 400 ppm PAC with a percentage of TSS removal of 92.093% from 2150 mg / L to 170 mg / L, and a decrease in COD of 85.343% from 1310 mg / L to 192 mg / L. The results obtained show that it is in accordance with the standards of the Ministry of Environment and Forestry Regulation No.5 of 2014.

Effectiveness of Utilization Kerang Dara Shell’s (Andara Granosa) As A Coagulants in Industrial Waste Water Treatment Processing

Andara granosa shell is one of the bivalves that is found in Indonesia. The high level of andara granosa is meat consumption without being followed by right processing of the shells, makes andara granosa shells become a waste that distrupts the environment. Andara granosa is contain a lot of CaCO3 Andara granosa shells contain a lot of CaCO3 which makes it can be used as a coagulant. Shells containing CaCO3 are converted into CaO (Calcite) first by the process of calcination. In this study, calcite was obtained through the process of calcining of andara granosa shells at 800 °C for 4 hours, which was dried and destructed before. The calcite optimization test in andara granosa is done by analyzing the ratio of calcite concentration variation (600 ppm, 700 ppm, 800 ppm, 900 ppm, 1000 ppm) to the decrease in BOD, COD, and TSS values in industrial liquid waste. The test results show the optimal optimal decrease in BOD, COD, and TSS values is at a concentration of 900 ppm with an effectiveness of 80.53%. The relationship between the concentration of coagulant to decrease in BOD value is shown by the equation y = -6.7043x2-50.275x + 599.83 and R2 = 0.9356,% effectiveness of COD 81.16%. The relationship between the concentration of coagulant to decrease in COD value is shown by the equation y = -4.3214x2-130.15 x + 1033.4 and R2 = 0.9492,% effectiveness of TSS 96.10%. The relationship between coagulant concentrations and the decrease in TSS values is shown by the equation y = 32.611x2-304.24x + 697.95 and R2 = 0.9088. Thus calcite with raw material of blood shells can reduce the optimal BOD, COD, and TSS values at a concentration of 900ppm.

Purple phototrophic bacteria are outcompeted by aerobic heterotrophs in the presence of oxygen

There is an ongoing debate around the effect of microaerobic/aerobic conditions on the wastewater treatment performance and stability of enriched purple phototrophic bacteria (PPB) cultures. It is well known that oxygen-induced oxidative conditions inhibit the synthesis of light harvesting complexes, required for photoheterotrophy. However, in applied research, several publications have reported efficient wastewater treatment at high dissolved oxygen (DO) levels. This study evaluated the impact of different DO concentrations (0-0.25 mg·L−1, 0-0.5 mg·L−1 and 0-4.5 mg·L−1) on the COD, nitrogen and phosphorus removal performances, the biomass yields, and the final microbial communities of PPB-enriched cultures, treating real wastewaters (domestic and poultry processing wastewater). The results show that the presence of oxygen suppressed photoheterotrophic growth, which led to a complete pigment and colour loss in a matter of 20-30 h after starting the batch. Under aerobic conditions, chemoheterotrophy was the dominant catabolic pathway, with wastewater treatment performances similar to those achieved in common aerobic reactors, rather than those corresponding to phototrophic systems (i.e. considerable total COD decrease (45-57% aerobically vs. ± 10% anaerobically). This includes faster consumption of COD and nutrients, lower nutrient removal efficiencies (50-58% vs. 72-99% for NH4+-N), lower COD:N:P substrate ratios (100:4.5-5.0:0.4-0.8 vs. 100:6.7-12:0.9-1.2), and lower apparent biomass yields (0.15-0.31 vs. 0.8-1.2 g CODbiomass·g CODremoved−1)). The suppression of photoheterotrophy inevitably resulted in a reduction of the relative PPB abundances in all the aerated tests (below 20% at the end of the tests), as PPB lost their main competitive advantage against competing aerobic heterotrophic microbes. This was explained by the lower aerobic PPB growth rates (2.4 d−1 at 35 °C) when compared to common growth rates for aerobic heterotrophs (6.0 d−1 at 20 °C). Therefore, PPB effectively outcompete other microbes under illuminated-anaerobic conditions, but not under aerobic or even micro-aerobic conditions, as shown by continuously aerated tests controlled at undetectable DO levels. While their aerobic heterotrophic capabilities provide some resilience, at non-sterile conditions PPB cannot dominate when growing chemoheterotrophically, and will be outcompeted.

Potential and characterization biogas from tofu liquid waste with addition cow dung and effective microorganisms 4 as biocatalyst

Energy is a source that needed by human life and cannot be separated. Fossil fuel has historically been the world’s most used energy source. However, the source of energy from fossil fuels has decreased, so it necessary to develop alternative energy sources. One of the energy sources that can be used is biogas. Organic wastes such as tofu liquid waste (TLW) and cow dung can be used as a source of biogas energy, because these organic wastes are known to have high methane gas content. The purpose of this research is to determine the optimum temperature and pH during the process fermentation of biogas, the content of biogas compounds analyse, the theoretical calorific value of biogas, as well as the BOD, COD, and TSS content of organic waste before and after fermentation process. The biogas production takes place through anaerobic digestion for about 35 days. From the results of this study, the highest CH4 gas content was 90.351%. The result of theoretical biogas calorific value was 50148.932 kJ/kg for HHV and 46908.932 kJ/kg for LHV, temperature conditions in range of 25–30 °C and a pH value in the range of 7.0 to 8.0. Besides producing energy, the organic waste fermentation process can also reduce levels of organic pollutants BOD, COD, and TSS in the liquid waste used. The highest decrease in BOD, COD, and TSS levels were 97.52%; 91.12%; and 91.22%.

Study on the model of domestic sewage resource utilization

In recent years, with the degree of urban-rural integration, the economic level of rural areas and the improvement of residents’ health awareness, the water quality pollution of rural domestic sewage has increased year by year, and the problem of rural sewage discharge has become increasingly prominent. In order to improve the rural water environment and solve the problem of random discharge of sewage, this paper takes the rural domestic sewage as the research object, and takes the natural sedimentation and anaerobic fermentation as the main means to study the on-site resource utilization technology of sewage. It was found that after 3 hours of sewage sedimentation, organic suspended solids settled naturally, resulting in a significant decrease of COD in the upper sewage to 93.29 mg/L. Because of the special bimolecular structure of LAS, the concentration of LAS in surface sewage increased sharply to 7.68mg/L, but it was lower than 10mg/L, which met the irrigation water standard.

Enhancing algal biomass production and nutrients removal from municipal wastewater via a novel mini photocavity bioreactor

This study presents the use of a novel photocavity reactor in order to intensify the growth rate, biomass and lipid productivity in microalgae. The reactor offers an aseptic approach for better control on growth rate in microalgae.The Absorption Factor (AF), Attenuation Factor (AtF), Modified Fluence Rate (MFR) and water factor of the photo reactor were recorded to be 1.581, 0.267, 0.347 mW/cm2 and 2.072 respectively. The maximum growth rate recorded was 310 mg L−1 inphotocavity reactor. The results clearly indicate that using the stainless steel visible photoreactor can lead to a significant increase in the growth rate (43.3%), productivity of biomass (27-33%) and lipid content (6-8%) in comparison to microalgae cultivated in glass conical flasks (control). COD, total nitrogen, phosphate and bacterial load (colony-forming unit- CFU) were determined in this study. A decrease in COD (180 to 19 mg/l) and CFU (57×109 to 5×101) of wastewater was also recorded in this study.