scholarly journals Greywater characterization and handling practices among urban households in Ghana: the case of three communities in Kumasi Metropolis

2017 ◽  
Vol 76 (4) ◽  
pp. 813-822 ◽  
Author(s):  
Bismark Dwumfour-Asare ◽  
Philomina Adantey ◽  
Kwabena Biritwum Nyarko ◽  
Eugene Appiah-Effah
Keyword(s):  
Oxygen Demand ◽  
Biological Processes ◽  
Organic Micropollutants ◽  
Salmonella Spp ◽  
Urban Households ◽  
Challenge And Threat ◽  
Average Water ◽  
Per Capita ◽  
Handling Practices ◽  
Greywater Reuse

Greywater management in Ghana receives little or no attention although untreated greywater is associated with environmental and public health risks. This paper assesses greywater characteristics and handling practices among urban households in three selected communities in Kumasi, the second largest city of Ghana. The study involved in-depth surveys (interviews and observations) with 90 households, and collection of 18 greywater samples from nine greywater sources for laboratory analysis. Average greywater generation is 43.36 ± 17 litres per capita per day, equivalent to 36% of average water consumption. Greywater is untreated before disposal (≈99%), and disposal is mainly (89%) into drains and onto streets. Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) levels are high but give very low BOD/COD ratios (0.20 ± 0.07) indicating a very low biodegradability potential. Nutrient levels are high: 12 times (P) and 30 times (N) in excess of standard discharge limits. Other contaminants detected are heavy metals (Fe, Pb, Zn and Cd), microbes (total coliforms, Escherichia coli and Salmonella spp.), and organic micropollutants – benzalkonium chloride, parabens (methyl and propyl), sodium benzoate and hypochlorite – and details of the levels are discussed in the paper. Greywater reuse could be useful for biomass production, but it also presents a challenge and threat to natural biological processes and water sources.

scholarly journals Will We Soon Run Out of Water?

2021 ◽  
pp. 1-7
Author(s):  
Ghislain de Marsily
Keyword(s):  
Food Habits ◽  
Food Production ◽  
Meat Consumption ◽  
Good Health ◽  
World Population ◽  
Total Food ◽  
Food Deficit ◽  
The World ◽  
Average Water ◽  
Per Capita

In 2000, the World population was 6.2 billion; it reached 7 billion in 2012 and should reach 9.5 billion (±0.4) in 2050 and 11 billion (±1.5) in 2100, according to UN projections. The trend after 2100 is still one of global demographic growth, but after 2060, Africa would be the only continent where the population would still increase. The amount of water consumed annually to produce the food necessary to meet the needs varies greatly between countries, from about 600 to 2,500 m<sup>3</sup>/year per capita, depending on their wealth, their food habits (particularly meat consumption), and the percentage of food waste they generate. In 2000, the total food production was on the order of 3,300 million tons (in cereal equivalents). In 2019, about 0.8 billion inhabitants of the planet still suffer from hunger and do not get the nutrition they need to be in good health or, in the case of children, to grow properly (both physically and intellectually). Assuming a World average water consumption for food of 1,300 m<sup>3</sup>/year per capita in 2000, 1,400 m<sup>3</sup>/year in 2050, and 1,500 m<sup>3</sup>/year in 2100, a volume of water of around 8,200 km<sup>3</sup>/year was needed in 2000, 13,000 km<sup>3</sup>/year will be needed in 2050, and 16,500 km<sup>3</sup>/year in 2100. Will that much water be available on earth? Can there be conflicts related to a food deficit? Some preliminary answers and scenarios for food production will be given from a hydrologist viewpoint.

High-strength wastewater treatment in a pure oxygen thermophilic process: 11-year operation and monitoring of different plant configurations

2015 ◽  
Vol 71 (4) ◽  
pp. 588-596 ◽  
Author(s):  
M. C. Collivignarelli ◽  
G. Bertanza ◽  
M. Sordi ◽  
R. Pedrazzani
Keyword(s):  
Performance Improvement ◽  
Oxygen Demand ◽  
High Strength ◽  
High Variability ◽  
Pure Oxygen ◽  
Biological Processes ◽  
Specific Biomass ◽  
Plant Monitoring ◽  
Nitrate And Nitrite ◽  
Biological Treatability

This research was carried out on a full-scale pure oxygen thermophilic plant, operated and monitored throughout a period of 11 years. The plant treats 60,000 t y−1 (year 2013) of high-strength industrial wastewaters deriving mainly from pharmaceuticals and detergents production and landfill leachate. Three different plant configurations were consecutively adopted: (1) biological reactor + final clarifier and sludge recirculation (2002–2005); (2) biological reactor + ultrafiltration: membrane biological reactor (MBR) (2006); and (3) MBR + nanofiltration (since 2007). Progressive plant upgrading yielded a performance improvement chemical oxygen demand (COD) removal efficiency was enhanced by 17% and 12% after the first and second plant modification, respectively. Moreover, COD abatement efficiency exhibited a greater stability, notwithstanding high variability of the influent load. In addition, the following relevant outcomes appeared from the plant monitoring (present configuration): up to 96% removal of nitrate and nitrite, due to denitrification; low-specific biomass production (0.092 kgVSS kgCODremoved−1), and biological treatability of residual COD under mesophilic conditions (BOD5/COD ratio = 0.25–0.50), thus showing the complementarity of the two biological processes.

scholarly journals Biofilm Forming Bacteria during Thermal Water Reinjection

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Máté Osvald ◽  
Gergely Maróti ◽  
Bernadett Pap ◽  
János Szanyi
Keyword(s):  
Thermal Water ◽  
Oxygen Demand ◽  
Geothermal System ◽  
Biological Processes ◽  
Geothermal Systems ◽  
The Past ◽  
Surface System ◽  
Buffer Tank ◽  
Physical And Chemical ◽  
Phenol Index

Reinjection of heat-depleted thermal water has long been in the center of scientific interest in Hungary regarding around 1000 operating thermal wells. While the physical and chemical aspects of reinjection have partly been answered in the past years, the effects of biological processes are still less known. We carried out our investigations in the surface elements of the Hódmezővásárhely geothermal system which is one of the oldest operating geothermal systems in Hungary. About one-third of the used geothermal water has been reinjected since 1998 by two reinjection wells at the end of the thermal loops. During the operation, plugging of the surface system was experienced within a few-day-long period, due to biological processes. The goal of our research was to find the dominant species of the microbial flora and to make a proposal to avoid further bacterial problems. We found that the reinjected, therefore the produced, water’s chemical oxygen demand, phenol index, and BTEX composition basically determine the appearing flora on the surface. When the concentration of these compounds in the thermal water is significant and residence time is long enough in the buffer tank, certain bacteria can be much more dominant than others, thus able to form a biofilm which plugs the surface equipment much more than it is expected.

scholarly journals The role of a chemical loop in removal of hazardous contaminants from coke oven wastewater during its treatment

2019 ◽  
Vol 17 (1) ◽  
pp. 1288-1300
Author(s):  
Anna Kwiecińska-Mydlak ◽  
Marcin Sajdak ◽  
Katarzyna Rychlewska ◽  
Jan Figa
Keyword(s):  
Chemical Treatment ◽  
Treatment Process ◽  
Oxygen Demand ◽  
Coke Oven ◽  
Main Role ◽  
Biological Processes ◽  
Coal Processing ◽  
Wastewater Treatment Process ◽  
Iron Based

AbstractCoke oven liquor is one of the most contaminated liquid streams generated by the coal processing industry, thus its proper treatment and utilization is crucial for sustainable and environmentally neutral plant operation. The conventional wastewater treatment process comprises of chemical and biological processes. Within the current research the detailed role of chemical treatment is described. Commercially available iron-based coagulants (PIX100, PIX100COP, PIX113, PIX116) were tested to understand their removal efficiency and impact on the stream parameters. The influence of iron dose in the range of 300-500 mgFe/L on the process performance was also examined.It was found that the main role of chemical treatment was to bind toxicants harmful to activated sludge microorganisms, i.e. free and complex cyanides and sulphides. Among the tested iron-based conventional coagulants ferrous salts were more efficient than ferric salts. It was also observed that efficiency of the process strongly depended on wastewater properties (especially in regard to pH, which should be in the range of 9-10) and the coagulant selection needed to be done individually for a given wastewater type. The removal rates of particular contaminants were diversified and for free cyanides, complex cyanides and sulphides they were in the range of 23-91%, -156-77% and -357-98%, respectively. The expected, simultaneous removal of chemical oxygen demand (COD) during the treatment was not observed and even the parameter value increased after the process due to probable formation of compounds less vulnerable to oxidation.

scholarly journals Food waste volume and composition in households in Greece

2019 ◽  
Keyword(s):  
Food Waste ◽  
Field Data ◽  
Food Item ◽  
Waste Generation ◽  
Waste Collection ◽  
Urban Households ◽  
Household Food ◽  
Actual Field ◽  
Capita Food ◽  
Per Capita

<p>The purpose of this paper is the presentation of the results compiled from self weighing of household food waste and self filling of waste collection diaries that took place in Greece. A diary was compiled and given to 101 urban households in various areas of the country. The participants were asked to weigh and write down in the diary every food item wasted in their households for two full weeks (i.e., 14 days). The total per capita food waste generation in Greece is estimated to be 76.1 (±68.3) kg/inh.y. This figure is divided into the avoided food waste fraction which equals to 25.9 (±34.9) kg/inh.y, and the unavoidable fraction which is estimated to be 50.2 (±47.1) kg/inh.y. The use of diaries for recording food that is thrown away from households is a methodology that underestimates the food wasted in households because households tend to be cautious when they know that they have to weigh and report the amount of food that they throw away. The current research is the first of its kind, presenting actual field data for food waste generation by households in Greece.</p>

Assessing the potential of a UV-based AOP for treating high-salinity municipal wastewater reverse osmosis concentrate

2013 ◽  
Vol 68 (9) ◽  
pp. 1994-1999 ◽  
Author(s):  
Muhammad Umar ◽  
Felicity Roddick ◽  
Linhua Fan
Keyword(s):  
Reverse Osmosis ◽  
Municipal Wastewater ◽  
High Salinity ◽  
Oxygen Demand ◽  
Process Efficiency ◽  
Secondary Effluent ◽  
Biological Processes ◽  
Fluorescence Excitation ◽  
H2o2 Treatment ◽  
Humic Compounds

The UVC/H2O2 process was studied at laboratory scale for the treatment of one moderate (conductivity ∼8 mS/cm) and two high salinity (∼23 mS/cm) municipal wastewater reverse osmosis concentrate (ROC) samples with varying organic and inorganic characteristics. The process efficiency was characterized in terms of reduction of dissolved organic carbon (DOC), chemical oxygen demand (COD), colour and absorbance at 254 nm (A254), and the improvement of biodegradability. The reduction of colour and A254 was significantly greater than for DOC and COD for all samples due to the greater breakdown of humic compounds, as confirmed by fluorescence excitation-emission matrix spectra. Fairly small differences in the reduction of DOC (26–38%) and COD (25–37%) were observed for all samples, suggesting that the salinity of the ROC did not have a significant impact on the UVC/H2O2 treatment under the test conditions. The biodegradability of the treated ROC samples improved markedly (approximately 2-fold) after 60 min UVC/H2O2 treatment. This study indicates the potential of UVC/H2O2 treatment followed by biological processes for treating high-salinity concentrate, and the robustness of the process where the characteristics of the secondary effluent (influent to RO) and thus resultant ROC vary significantly.

scholarly journals Evaluation Methods of Water Environment Safety and Their Application to the Three Northeast Provinces of China

2019 ◽  
Vol 11 (18) ◽  
pp. 5135 ◽  
Author(s):  
Li ◽  
Sun ◽  
Yuan ◽  
Liu
Keyword(s):  
Principal Component Analysis ◽  
Water Resources ◽  
Chemical Oxygen Demand ◽  
Water Environment ◽  
Oxygen Demand ◽  
Principal Component ◽  
Component Analysis ◽  
Analysis Method ◽  
Industry Output ◽  
Per Capita

Focusing on the topic of water environment safety of China, this paper has selected the three northeast provinces of China as the research object due to their representativeness in economic development and resource security. By using the Entropy Weight Method, the Grey Correlation Analysis Method, and the Principal Component Analysis Method, this paper has first constructed a water environment safety evaluation system with 17 indicators from the economic, environmental, and ecological aspects. Furthermore, this paper has screened the initially selected indicators by the Principal Component Analysis Method and finally determined 11 indicators as the evaluation indicators. After indicator screening, this paper has adopted the improved Fuzzy Comprehensive Evaluation Method to evaluate the water environment safety of the three northeast provinces of China and obtained the change in water environment safety of different provinces from 2009 to 2017. The results show that the overall water environment safety of the region had improved first but worsened afterward, and that in terms of water safety level, Jilin Province ranked first, followed by Heilongjiang Province and Liaoning Province. The three factors that have the greatest impact on the water environment safety of the three provinces are: Liaoning—Chemical Oxygen Demand (score: 17.10), Per Capita Disposable Income (score: 13.50), and Secondary Industry Output (score: 11.50); Heilongjiang—Chemical Oxygen Demand (score: 18.64), Per Capita Water Resources (score: 12.75), and Concentration of Inhalable Particles (score: 10.89); Jilin—Per Capita Water Resources (score: 15.75), Chemical Oxygen Demand (score: 14.87), and Service Industry Output (score: 11.55). Based on analysis of the evaluation results, this paper has proposed corresponding policy recommendations to improve the water environment safety and promote sustainable development in the northeast provinces of China.

Environmental performance of an integrated fixed-film activated sludge (IFAS) reactor treating actual municipal wastewater during start-up phase

2015 ◽  
Vol 72 (10) ◽  
pp. 1840-1850 ◽  
Author(s):  
Nitin Kumar Singh ◽  
Absar Ahmad Kazmi ◽  
Markus Starkl
Keyword(s):  
Activated Sludge ◽  
Pathogenic Bacteria ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Lessons Learned ◽  
Present System ◽  
Salmonella Spp ◽  
Start Up ◽  
Fixed Film

The present study summarizes the start-up performance and lessons learned during the start-up and optimization of a pilot-scale plant employing integrated fixed film activated sludge (IFAS) process treating actual municipal wastewater. A comprehensive start-up was tailored and implemented to cater for all the challenges and problems associated with start-up. After attaining desired suspended biomass (2,000–3,000 mg/L) and sludge age (∼7 days), the average biological oxygen demand (BOD) and chemical oxygen demand (COD) removals were observed as 77.3 and 70.9%, respectively, at optimized conditions, i.e. hydraulic retention time (HRT), 6.9 h; return sludge rate, 160%. The influent concentrations of COD, BOD, total suspended solids, NH3-N, total nitrogen and total phosphorus were found to be in the range of 157–476 mg/L, 115–283 mg/L, 152–428 mg/L, 23.2–49.3 mg/L, 30.1–52 mg/L and 3.6–7.8 mg/L, respectively, and the minimum effluent concentrations were achieved as ∼49 mg/L, 23 mg/L, 35 mg/L, 2.2 mg/L, 3.4 mg/L and 2.8 mg/L, respectively, at optimum state. The present system was found effective in the removal of pathogenic bacteria (Escherichia coli, 79%; Salmonella spp., 97.5%; Shigella spp., 92.9%) as well as coliforms (total coliforms, 97.65%; faecal coliforms, 80.35%) without any disinfection unit. Moreover it was observed that the time required for the stabilization of the plant was approximately 3 weeks if other parameters (sludge age, HRT and dissolved oxygen) are set to optimized values.

Bacteriological Analysis of Ready-to-eat Foods from Morogoro Municipal Market

2020 ◽  
Vol 37 ◽  
pp. 17-24
Author(s):  
J.N. Ndunguru ◽  
D.G. Ndossi
Keyword(s):  
Bacterial Contamination ◽  
Food Poisoning ◽  
Food Preparation ◽  
Salmonella Spp ◽  
Street Vendors ◽  
Bacteriological Analysis ◽  
Additional Information ◽  
Microbiological Methods ◽  
Handling Practices

Street vendors supply large quantities of food at affordable prices in many places especially in developing countries. Street foods are common sources of bacteriological contamination causing food poisoning, diarrhea, cholera and typhoid fever. This study analyzed the bacteriological quality of ready-to-eat foods vended in Morogoro Municipal Market. A total of 70 samples from different street foods were randomly collected from different vendors and transported in cool boxes to the laboratory for bacteriological analysis. Standard microbiological methods were used for isolation, enumeration and identification of bacteria. Additional information regarding food preparation, storage and handling practices observed by vendors was noted to correlate with the extent of bacterial contamination. Majority (67.1%) of the ready to eat foods were contaminated with bacteria. Vegetable salads and Potato fries showed highest bacterial contamination rates (78.6%). Escherichia coli (49.2%) was the major isolate in all food types. Other bacteria isolated were Bacillus cereus (19.7%), Staphylococcus aureus (14.8%), Klebsiella pneumoniae (14.8%) and Salmonella spp. (1.6%). E. coli was resistant to some antimicrobials (carbenicilin, clindamycin and tetracycline). High levels of bacterial contamination were associated with poor hygiene of vendors, unsafe food handling practices and use of contaminated water in food preparation.  Although the presence of the microorganisms is not necessarily a threat to human health, the fact that some microorganisms were resistant to some antibiotics is of concern. Provision of sanitation and hygiene education to vendors and regulations for implementation of good hygienic practices can improve quality of street foods

Study on Environmental Materials with Application of Ozone-Based Technologies in Removal of Characteristic Pollutants in Pulp and Paper Effluents

2013 ◽  
Vol 700 ◽  
pp. 35-40
Author(s):  
Li Rong Lei ◽  
You Ming Li
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Oxygen Demand ◽  
Development Trend ◽  
Research Process ◽  
Pulp And Paper ◽  
Biological Processes ◽  
High Concentration ◽  
Emission Standard ◽  
Environmental Materials ◽  
Organic Halogens

Due to the presence of recalcitrant organic compounds, the pulp and paper effluents after treatment by conventional biological processes still contain high concentration of chemical oxygen demand (COD) and colored substances and do not satisfy the national emission standard. The objectives of this work are to present the research process on environmental materials with application of ozone-based technologies in removal of characteristic pollutants in pulp and paper effluents and suggest the feasible development trend. In this work, basic mechanisms of degradation of organic pollutants by ozone-based technologies in the presence of environmental materials as catalyst are described. The removal efficiencies of characteristic pollutants commonly found in pulp and paper effluents, such as absorbable organic halogens (AOX), resin and fatty acids, phenolic compounds, lipophilic wood extractives and ethylenediaminetetraacetic acid (EDTA), are presented.

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