Drainage Wastewater Research Articles

Integration of Water Quality Indices and Multivariate Modeling for Assessing Surface Water Quality in Qaroun Lake, Egypt

Water quality has deteriorated in recent years as a result of rising population and unplanned development, impacting ecosystem health. The water quality parameters of Qaroun Lake are contaminated to varying degrees, particularly for aquatic life consumption. For that, the objective of this work is to improve the assessments of surface water quality and to determine the different geo-environmental parameters affecting the lake environmental system in Qaroun Lake utilizing the weighted arithmetic water quality index (WAWQI) and four pollution indices (heavy metal pollution index (HPI), metal index (MI), contamination index (Cd), and pollution index (PI), that are enhanced by multivariate analyses as cluster analysis (CA), principal component analysis (PCA), and support vector machine regression (SVMR). Surface water samples were collected at 16 different locations from the lake during years 2018 and 2019. Thirteen physiochemical parameters were measured and used to calculate water quality indices (WQIs). The WQIs of Qaroun Lake such WAWQI, HPI, MI, Cd, PI revealed a different degree of contamination, with respect to aquatic life utilization. The WQIs result revealed that surface water in the lake is unsuitable, high polluted, and seriously affected by pollution for an aquatic environment. The PI findings revealed that surface water samples of Qaroun Lake were significantly impacted by Al, moderately affected by Cd and Cu, and while slightly affected by Zn due to uncontrolled releases of domestic and industrial wastewater. Furthermore, increasing salinity accelerates the deterioration of the lake aquatic environment. Therefore, sewage and drainage wastewater should be treated before discharging into the lake. The SVMR models based on physiochemical parameters presented the highest performance as an alternative method to predict the WQIs. For example, the calibration (Val.) and the validation (Val.) models performed best in assessing the WQIs with R2 (0.99) and with R2 (0.97–0.99), respectively. Finally, a combination of WQIs, CA, PCA, and SVMR approaches could be employed to assess surface water quality in Qaroun Lake.

Purification of filtering drainage wastewater of solid waste landfills with modified coagulant solutions

Purification of filtering drainage wastewater of solid waste landfills with modified coagulant solutions

Steady-State Hydraulic Analysis of High-Rise Building Wastewater Drainage Networks: Modelling Basis

A model is presented which allows steady-state pressure profiles in high-rise wastewater drainage networks to be related to intake air flowrates and discharge water flowrates. This model is developed using data taken from academic literature, and is based on experimental observations which suggest that a vertical annular downflow develops over distance such that the pressure gradient in the wet stack may be expressed as the sum of junction components and developed flow components. The model is used to analyse a simplified ‘medium rise’ primary vented system of height 40 m, hosting two inflow junctions, crossvents and Air Admittance Valves (AAVs). The model illustrates how the air supply configuration affects the airflow rates within the stack and the vents, and how the configuration affects the steady-state hydraulic pressure profile. The model offers the possibility of an alternative approach to the design of high-rise wastewater drainage networks, compared to existing design codes. These codes generally do not explain the role that the air admitted into the network has upon its performance.

Molecular Phylogenetics and Population Genetics of the Dengue Vector Aedes aegypti From the Arabian Peninsula.

Aedes aegypti mosquito is the principal dengue vector in the Kingdom of Saudi Arabia (KSA); however, no study has addressed its ecology and population structure yet. Therefore, we report on Ae. aegypti phylo- and population genetics using three DNA markers: COI, ND4, and rDNA-ITS2. Sampling the immature stages of Ae. aegypti revealed that water storage tanks (34.3% of habitats) were the most productive and contained 33% of immatures stages. Other important habitats included containers for wastewater drainage (including air-conditioning and water cooler trays) and containers associated with ornamentation. Shallow water leakage spots (2.7% of habitats, 8% of immatures) can be considered rare-but-epidemiologically-important containers. Neighbor-joining (NJ) phylogenetic analysis of Ae. aegypti identified 8, 14, and 9 haplotypes of COI, ND4, and ITS2, respectively, and revealed high levels of genetic variation in Ae. aegypti populations of KSA. Global distribution of haplotypes also indicated multiple gene introductions into these populations, with high levels of intra-population genetic variation and continuous gene exchange. The neutrality values indicated a deficiency of alleles and suggested that the KSA Ae. aegypti loci tested did not follow a neutral model of molecular evolution. Fst values and AMOVA indicated that most of the genetic variation in the KSA Ae. aegypti populations is due to intra- rather than inter-population differences. This is the first comprehensive report on the phylo- and population genetics of Ae. aegypti from the Arabian Peninsula. This information expands our understanding of the ecology and population dynamics of this important arboviral vector for informed control efforts.

Klebsiella pneumoniae Carbapenemase (KPC)–Producing K. pneumoniae Contamination of an In-Room Sink in a New Bed Tower

Group Name: Duke Center for Antimicrobial Stewardship and Infection PreventionBackground: Wastewater drains in hospital patient rooms have been identified as environmental reservoirs for multidrug-resistant organisms, and they have been linked to outbreaks of carbapenem-resistant Enterobacteriaceae (CRE). We studied the colonization of wastewater drains in a new hospital bed tower. Methods: A patient care unit in a new bed tower opened on July 18, 2020. In-room sinks were located in each hospital room opposite the patient head wall. Patients admitted to this unit underwent weekly rectal cultures to survey for carbapenemase-producing CRE. Additionally, infection preventionists performed routine surveillance of all clinical cultures for CRE. Cultures were performed from all patient room sinks in this unit monthly beginning September 14, 2020. Samples were obtained from the drain cover, handles, and top of bowl using sponges soaked in neutralizing buffer and processed using the stomacher technique. The tail-pipe was sampled using a flocked mini-tip swab soaked in neutralizing buffer; the P-trap water was sampled with sterile tubing attached to a 50-mL syringe. All samples were plated on HARDYCHROM-ESBL and KPC Colorex media and were incubated at 37°C for 24 hours. Results: The first identified CRE-positive patient was admitted to the new unit on December 4, 2020; urine culture obtained at the time of admission grew KPC–producing Klebsiella pneumoniae (KPC-KP). The sink in this patient’s room had been sampled 3 prior times (most recently on November 9, 2020) and was negative for CRE. On December 7, 2020, KPC-KP was found on the drain cover (6,750 colony-forming units, CFU) and in the sink’s P-trap (1,840 CFU) of the index patient’s room during routine sink surveillance. Additional samples from other room surfaces were taken on December 9, 2020, and KPC-KP was recovered from the computer keyboard (452 CFU) and patient bedrails (880 CFU). The patient was discharged from this room December 13, 2020, and the room underwent enhanced terminal room cleaning including UV-C light. On the next routine sink sampling on January 4, 2021, KPC-KP was recovered again in the index room sink P-trap (9,800 CFU) but at no additional sites. MLST was performed, and all isolates were ST-258. Conclusions: In a new bed tower with no prior evidence of CRE-positive patients, the first identified case of a CRE (KPC-KP) in a patient resulted in widespread environmental contamination of the room after only 3 days of hospitalization and contamination of the in-room sink drain that persisted after 1 month. Given the ease with which CRE colonizes wastewater drains, new strategies are needed to mitigate drain colonization and to prevent CRE transmission to subsequent patients.Funding: NoDisclosures: None

Design of Sewer System for Holkarwadi Village by using Sewer GEMS Software

Globally there has been a massive increase in the population Numbers, especially in India the rate of Increase is on a higher side. To inculcate The rising population, cities expand giving Rise to urbanization. This calls for Provision of various basic public service Amenities such as water pipeline, drainage Pipeline, roads, street lights, etc. The Waste water collection/drainage system is One if the basic public service entities Needed to maintain proper hygiene in a Locality since sanitation is a primary Aspect of public health in a society. This Project aims at modelling a Geographical Information System (GIS) based waste Water drainage system using QGIS and Bentley SewerGEMS software. The Village situated in the southern eastern Region of the city of Pune, Holkarwadi was Selected as it has been recently included in City limits and therefore has a need of a Well-designed waste-water drainage System.

Performance of microbial community dominated by Bacillus spp. in acid mine drainage remediation systems: A focus on the high removal efficiency of SO42-, Al3+, Cd2+, Cu2+, Mn2+, Pb2+, and Sr2+

A consortium of microbial community was used for the treatment of acid mine drainage wastewater laden with sulphate and heavy metals. The wastewater was treated in an anaerobic continuously stirred tank bioreactor. The microbial community activity increased the pH from 5.6 to 6.5, and improved sulphate removal up to 85% from an initial sulphate concentration of 8080 mg SO42−/L in a continuous mode, following enrichment for 21 d. The maximum heavy metal removal percentage was observed for Cd (98%), Al (97%), Mn (95%), Pb (94%), Sr (94%) and Cu (91%). The microbial community showed synergy between strictly anaerobic and facultative Firmicutes sp., which were responsible for the bioreactor performance. The biochemical reaction indicated the microbial community has a wider range of substrates dominated by metallo-aminopeptidases.

Outbreak of OXA-48-producing Enterobacterales in a haematological ward associated with an uncommon environmental reservoir, France, 2016 to 2019.

The hospital water environment, including the wastewater drainage system, is increasingly reported as a potential reservoir for carbapenemase-producing Enterobacterales (CPE). We investigated a persistent outbreak of OXA-48 CPE (primarily Citrobacter freundii) in a haematological ward of a French teaching hospital by epidemiological, microbiological and environmental methods. Between January 2016 and June 2019, we detected 37 new OXA-48 CPE-colonised and/or ‑infected patients in the haematological ward. In October 2017, a unit dedicated to CPE-colonised and/or ‑infected patients was created. Eleven additional sporadic acquisitions were identified after this date without any obvious epidemiological link between patients, except in one case. Environmental investigations of the haematological ward (June–August 2018) identified seven of 74 toilets and one of 39 drains positive for OXA-48 CPE (seven C. freundii, one Enterobacter sakazakii, one Escherichia coli). Whole genome comparisons identified a clonal dissemination of OXA-48-producing C. freundii from the hospital environment to patients. In addition to strict routine infection control measures, an intensive cleaning programme was performed (descaling and bleaching) and all toilet bowls and tanks were changed. These additional measures helped to contain the outbreak. This study highlights that toilets can be a possible source of transmission of OXA-48 CPE.

Efficiency of Natural Clay Mineral Adsorbent Filtration Systems in Wastewater Treatment for Potential Irrigation Purposes

This project investigated the relative efficiencies of three pilot-scale constructed columns for enhancing drainage wastewater treatment processes to ensure compliance with Egyptian and international water quality criteria. In this investigation, basic materials (sand and gravel) and variable natural clay minerals zeolite (Z), diatomite (D) and bentonite (B) were utilized as packing materials to build up a Z column (ZC), D column (DC) and B column (BC), respectively. The three columns’ ability to remove pollutants from waste water for re-use in irrigation was investigated throughout one year (12 trials). The results revealed that the influent water had 211 mg/L total suspended solids, 6.09 mg/L total nitrogen, 36.67 mg/L biochemical oxygen demand, 56 mg/L chemical oxygen demand, 1700 mg/L total dissolved solids, 0.97 mg/L copper (Cu2+), 1.12 mg/L iron (Fe2+), 1.07 mg/L manganese (Mn2+), 1.02 mg/L lead (Pb2+), 1.05 mg/L zinc (Zn2+), and 46 × 103 CFU/mL fecal coliforms. These parameters were higher than the values permitted by Egyptian and international licenses. The range of removal efficiency of these pollutants by ZC was 96–21%, by BC was 99–29.8%, and by DC was 99–19.80%. Regeneration studies for the spent adsorbents demonstrated that the percentages of pollutant removal were sufficiently high. The treated effluent produced by the three columns was suitable for irrigation purposes, especially at a contact time of four hours, with the order for column treatment efficiency being BC ˃ DC ˃ ZC. Treated water was classified for irrigation suitability according to the Agrifood Water Quality Index (AFWQI) as marginal from the ZC, very good from the DC, and excellent from the BC. Treatment of such drainage water using the BC and DC appears feasible, because the process is easily operated and leads to final treated effluent of high quality for agricultural uses. The economic cost also confirms the feasibility of this treatment.

Comprehending the Causes of Presence of Copper and Common Heavy Metals in Sediments of Irrigation Canals in Taiwan

In 2019, Taiwan completed its first thorough heavy metal investigation of irrigation canal sediments by this study with the support of Taiwan Environmental Protection Administration. Box-and-whisker plots were used to analyze the sediment distribution and to define metal concentrations. Possible metal pollution sources, the polluted agricultural land, irrigation area, and water sources were also evaluated using spatial analysis to understand the possible causes of sediment pollution. Results showed that the main heavy metal in agricultural land was Cu, found in 77% of contaminated agricultural land sites. Most sites with Cu pollution in sediments were in Taoyuan City and Changhua County. The heavy metals present in the sediment pollution sites in Taoyuan were consistent with those of possible pollution sources upstream, namely, Cr, Cu, and Pb. The main heavy metals in sediment pollution sites in Changhua were Cr, Cu, Ni, Pb, and Zn, whereas those for the polluted agricultural land sites were Cr, Cu, Ni, and Zn, without Pb. The main irrigation water sources in Changhua include drainages and rivers, with some receiving most wastewater pollution mass of release of Changhua, and functions as an irrigation water source with a high release mass in Cr, Cu, Ni and Zn. These findings indicate that the sites of sediment pollution, sites of polluted agricultural land, and the sources of pollution share corresponding heavy metal characteristics. Therefore, in Changhua, the sediments were polluted mainly because (1) the irrigation canals received the highest masses of pollutant releases into drainage wastewater of the county; and (2) the return flow from irrigation and the illegal discharge of wastewater. The preliminary assessment results for sediment pollution in Taoyuan also suggest that the main causes may be irrigation by polluted rivers or drainages and return flows.

Assessment of Wastewater Quality of Paharang Drain and its Impact on the Ground Water Quality of Adjacent Areas

This study was conducted to assess the effect of wastewater quality of Paharang drain Faisalabad on ground water quality of adjacent areas. Ground water samples and drain water samples were collected and analyzed by using standard methods. Parameters of wastewater samples were compared with Pakistan National Environmental Quality Standards (NEQS). Results indicated that physico-chemical parameters including pH, total dissolved solids (TDS), chloride, fluoride and total hardness were found exceeding the permissible limits in wastewater samples. Similarly, few physicochemical parameters in groundwater were found within the permissible limit while electrical conductivity (EC), TDS, chlorides (Cl), fluoride (F), and total hardness in most of samples were found above the Pak EPA and WHO standard limits. Heavy metals like nickel (Ni), chromium (Cr), iron (Fe), lead (Pb), and arsenic (As) were found within the prescribed concentrations in drain and ground water samples. Statistical analysis showed significant effect of some drain wastewater parameters like conductivity, TDS, salt, temperature, and Cl on the corresponding ground water quality. A strong positive correlation between pH, EC, TDS, Salt, and Cl in drain wastewater and strong positive correlation between EC, TDS and Salt in ground water samples was observed. For improving the ground water quality in the adjacent areas textile wastewater treatment all factories is required, and a combined effluent treatment plant (CETP) at the Paharang drain is also recommended.

Year-long performance assessment of an on-site pilot scale (100 L) photobioreactor on nutrient recovery and pathogen removal from urban wastewater using native microalgal consortium

The study was carried out as part of the Indo-Dutch collaboration project to ascertain the efficacy of the algal system for the treatment of urban wastewater. The study was done at Barapullah drain in New Delhi, using a pilot-scale (100 L) bubble column microalgae photobioreactor (PBR). The year-long study was intended to find the impact of seasonality coupled with varying hydraulic retention times (HRTs) on the PBR performance in terms of nutrient recovery, microbial contamination reduction, biomass productivity, and theoretical biomethane potential.To begin with, native microalgae consortium was enriched and cultivated in PBR directly on the Barapullah drain wastewater at the drain site. After achieving maximum recovery of nutrients in the batch mode, the PBR was operated in continuous mode at HRTs ranging from 1 to 3 days during summer, while 2–3 days during monsoon, autumn, and winter. The maximum and minimum biomass productivity obtained was 260 mg L−1 d−1 at the HRT of 1 day during summer and 77 mg L−1 d−1 at the HRT of 2 days during winter. At peak overall PBR performance at HRT of 2 days, the nutrient removal rate was 37.2 ± 6.2 mgCOD L−1 d−1, 39.3 ± 6 mgN L−1 d−1, and 4.7 ± 0.7 mgP L−1 d−1. Nearly 5 log removal of total and faecal coliform was obtained during summer and monsoon. However, the overall performance reduced during winters. The natural sedimentation of grown biomass achieved 81–95% of biomass settling at different HRTs. The areal footprint of the PBR is 1.42 m2 KLD−1, which was significantly lower than other pilot-scale microalgal wastewater treatment technologies. The obtained results at this lower HRT (2 days) even under non-optimized process parameters represent vital improvements over earlier reports with significantly higher HRTs. Results thus highlight the feasibility and scalability of the technology.

Development of a domestic methodology for assessing the risks of acid effluent formation during storage and use of wastes from coal mining and processing

It is shown that the main ecologically significant characteristics of wastes from mining and processing of coal, which are considered when assessing their impact on the environment, are the indicators reflecting the risks of acidic water formation and leaching of macro- and microelements from rocks. A review of the methods used abroad to determine the risks of formation of acidic effluents during storage or use of wastes is carried out. It is shown that at present in the Russian Federation there is no regulatory support for assessing this indicator in wastes from mining, processing and combustion of coals. It is noted that for a preliminary assessment of the risks of acidic wastewater drainage, the most common method for determining the neutralization potential of waste is the so-called A. Sobek static test (ABA). The main stages of the development of the domestic method for determining the potential of neutralization in waste are presented and its approbation is carried out on existing research objects. The developed methodology takes into account the main provisions of the classical method for determining the neutralization potential of A. Sobek and makes additions to the procedure for testing of the samples, which makes it possible to increase the accuracy of the obtained results and extend the domestic methodology not only to wastes from mining and benefication of coals, but also to wastes from combustion and processing of coal, such as fly ash, slag and ash and slag wastes. The study was supported by the Russian Foundation for Basic Research, Grant No. 19-35-90117.

The formation of Fe colloids and layered double hydroxides as sequestration agents in the natural remediation of mine drainage

The increasing need to treat wastewater from mine effluents has drawn attention to passive treatment systems. Colloids are common in mine waters and are highly reactive, so their formation, characteristics, behavior, and the critical factors that affect them need to be understood for designing efficient treatment systems. An investigation was conducted at the abandoned Ainai mine drainage, Japan, where aeration is utilized to remove Fe, As, and Zn from circumneutral wastewater drainage, during rainy and dry seasons of 2016 and 2018 respectively, based on observations of physiochemical characteristics, elemental concentrations in dissolved and colloidal fractions, transmission electron microscopy, and synthetic experiments. In this circumneutral Fe-rich mine drainage, Fe2+ is oxidized to Fe3+, resulting in the formation of Fe colloids that incorporate As during their formation. Colloid formation increases turbidity, and, in the rainy season, increased colloidal interaction enhances their aggregation and higher flow rates lead to greater mobilization of the colloids. Zn-bearing colloids are rare in Ainai mine drainage because the Zn concentrations are low. However, Zn-Fe layered double hydroxide (LDH) was identified and confirmed by geochemical modelling and experiments. The Zn-Fe LDH was formed by isomorphous substitution of Zn into an Fe2+–Fe3+–CO32–LDH, at pH greater than 7.5, thereby achieving efficient natural remediation of Zn and As in the drainage.

Co-design of experimental nature-based solutions for decentralized dry-weather runoff treatment retrofitted in a densely urbanized area in Central America

The quality of water in many urban rivers in Latin America is increasingly degrading due to wastewater and runoff discharges from urban sprawl. Due to deficits in sanitary drainage systems, greywater is discharged to the stormwater drainage network generating a continuous dry-weather runoff that reaches rivers without treatment. One of the main challenges in the region is to achieve sustainable management of urban runoff for the recovery of rivers ecosystem integrity. However, retrofitting conventional centralized wastewater drainage networks into the existing urban grid represents important social, economic and technical challenges. This paper presents an alternative adaptive methodology for the design of Nature-based Solutions for decentralized urban runoff treatment. Through this study, technical solutions commonly used for stormwater management were adapted for dry-weather runoff treatment and co-designed for the particular conditions of a representative study area, considering space availability as the main constraining factor for retrofitting in urban areas. The application of a co-design process in a dense neighbourhood of the Great Metropolitan area of Costa Rica brought to light valuable insights about conditions that could be hindering the implementation of NBS infrastructures in Latin America.

ОПРЕДЕЛЕНИЕ ПЕРИОДА ГАРАНТИРОВАННОЙ БЕЗОТКАЗНОЙ РАБОТЫ ГИДРАВЛИЧЕСКОЙ СХЕМЫ НА ОСНОВЕ ЭКСПЛУАТАЦИОННЫХ ПОКАЗАТЕЛЕЙ НАДЕЖНОСТИ НАСОСНЫХ АГРЕГАТОВ

The article presents the values of the failure rate for modern types of pumps of four groups: submersible, designed for drainage and wastewater drainage; domestic; cantilever; submersible - for artesian water intake based on statistical data processing on their operation. The obtained values of the failure rate allow us to evaluate the reliability indicators of hydraulic circuits that use various types of pumping equipment. The article analyzes the failures of pumping equipment with their detailed description and presentation of practical photos accumulated at a specialized enterprise, whose activities are aimed at designing pumping stations, supply, installation and maintenance of pumping equipment on the territory of the Republic of Crimea.

ОЦІНКА АНТРОПОГЕННОГО НАВАНТАЖЕННЯ БІОГЕННИМИ ЕЛЕМЕНТАМИ ТА ОРГАНІЧНИМИ РЕЧОВИНАМИ У БАСЕЙНІ Р. ТЕТЕРІВ

Human economic activities carried out within river basins often lead to the deterioration of the general condition of water bodies. The main danger of excessive amounts of organic substances is the consumption of oxygen dissolved in water for their oxidation. As a result, conditions of oxygen deficiency occur in polluted waters until hypoxia processes. It leads to significant disruptions of biological groups, including the death of certain species. The entry of nutrients into surface water is the driving force of eutrophication. As a result, it leads to increasing in primary production and accumulation of organic substances in the water object. Phosphorus and nitrogen compounds play a dominant role among nutrients. According to the nature of the inflow of substances, point sources and diffuse sources are distinguished. The first one includes stationary water discharges. The second are represented by runoff from rural settlements and runoff from agricultural lands and built-up areas. The main ways of supply of biogenic elements and organic substances to the Teteriv basin are presented in the article. As point sources, the loads from communal services and industrial enterprises were determined separately. According to the reporting data of 2-TP Vodhosp, there are 13 industrial enterprises and 22 communal enterprises, the wastewater of which enters the Teteriv River. To analyze the diffuse inflow of nutrients the main ways of their inflow were used- from precipitation, water runoff from different types of cover (arable land, forests, meadows and pastures, settlements, rock outcrops, water surface), from the rural population. The Teteriv river is a right tributary of the Dnipro and the main source of water intake and drainage of municipal and industrial wastewater in Ukrainian Polissya. Zhytomyr city agglomeration with a total population of 587.2 thousand pers. with cities of regional significance Zhytomyr and Berdychiv are within the basin of the Teteriv. Reservoirs built in the basin create the necessary water reserves for the needs of the population and other facilities. It has been shown that among the point sources the main pollution is caused by the urban population. Significant pollution of the Teteriv River with organic substances and nutrients is caused by KP Zhytomyrvodokanal and Banknote Paper Factory (Malyn city). It is revealed that the main source of organic compounds is the households mostly of the rural population, which are not equipped with sewage. For nitrogen and phosphorus, the main source of emissions is an arable land.

Značaj postrojenja za prečišćavanje otpadnih voda za održivi razvoj

The concept of sustainable development has gained in its importance with the attempt to align the goals of economic development with the goals of preserving the quality of living environment. This paper explains the concept of sustainable development and its dimensions, emphasizing its connection with the communal activity of purification and drainage of atmospheric and wastewater. The evidence from the Republic of Serbia regarding wastewater treatment plants and environmental protection costs raises concerns about sustainability issues. Therefore, the aim of the paper is to point out the importance of increasing wastewater treatment plants' capacity and improving their operability, as well as to emphasize the necessity for structural changes of public utility companies to address the identified problems.

Сравнительный анализ расчетных зависимостей для гидравлического расчета самотечных сетей водоотведения

In this work, we carried out a comparative analysis of empirical dependences (A. Chézy and N.F. Fe-dorov formulas) for the hydraulic calculation of wastewater gravity flow networks. Using these formulas on a specific example, the hydraulic slope of a gravity pipeline was calculated and the error in the val-ues of the actual hydraulic potential characteristics of the pipes was determined. The data obtained showed that calculations using the Chézy formula ensure the highest accuracy. The A. Chézy formula was revised by introducing the concept of reduced pipe inner diameter. The dependency graph i = f (dpr) was plotted, indicating that the revised version of the A. Chézy formula gives more accurate re-sults than the classical one. The revised A. Chézy formula is recommended for the hydraulic calcula-tion of wastewater gravity flow networks. We proposed developing calculation tables for the hydraulic calculation of wastewater drainage flow networks with internal deposits.

Physicochemical and Bacteriological Quality of Groundwater, East of Nile Delta of Egypt

Groundwater is an important source of freshwater for drinking and irrigation purposes, and hence protecting it against depletion and deterioration is extremely required. Groundwater could get contaminated physically, chemically, or microbiologically. Each type of contamination is linked to different sources and in turn imposes different types of health problems and consequences. A water sample from Bahr Al-Baqar Wastewater drain and 13 groundwater samples were collected for physiochemical and bacteriological analyses to evaluate groundwater contamination in As-Salihiyyah and adjacent areas, east of Nile Delta of Egypt. Nitrate, COD, and BOD values collected from Bahr Al-Baqr drain and groundwater exceeded the Egyptian maximum permissible limit for drinking water (0.5, 6, 10, respectively). The total number of viable microorganisms (TVC) test for Bahr Al-Baqar drain was recorded as more than 300 CFU/mL, and the total coliform recorded 1100 MPN/100ml, indicating high level of contamination. The high count of the TVC (16-↑300 CFU/mL) for groundwater and the total coliform (3 - 1100 MPN/100ml) indicated that groundwater is contaminated and unsafe for drinking and might be affected by Bahr Al-Baqar wastewater drain.