scholarly journals Minimizing risks in wastewater reuse: proposed operational principles and guidelines for South Africa

2012 ◽  
Vol 2 (4) ◽  
pp. 227-238 ◽  
Author(s):  
J. R. Adewumi ◽  
A. A. Ilemobade ◽  
J. E. van Zyl

Treated wastewater represents a significant potential source of reclaimed water for some beneficial reuses. However, public concern over the risks/health-related hazards of wastewater reuse has limited the general acceptability of reuse systems in many countries. It is important to manage the operation of recycled water systems in such a way that it will not adversely affect public health and the environment. Management of recycled water involves process control and compliance monitoring. This paper presents proposed unit process monitoring guidelines to classify the performances of treatment units according to the pollutant removal efficiencies and frequency of sampling to test for effluent quality suitable for reuse. The paper also highlights the procedure for proper inspection of treatment facilities to ensure optimum performances. It proposes minimum quality requirements for different reuse activities in South Africa such as domestic (toilet flushing, watering private gardens), irrigation (crops, landscape, public parks and golf courses, cemeteries), industrial (system cooling and process water) and other activities (construction works, street cleaning, fire protection, groundwater recharge). By employing the wastewater treatment monitoring and sampling procedures proposed in this paper, health-related hazards can be minimized while public confidence in reuse schemes will be enhanced.

Author(s):  
S Mamane ◽  
A Abimbade ◽  
A Ilemobade

ABSTRACT Increasing scarcity of freshwater resources and growing environmental awareness have given rise to the use of treated wastewater as an additional source of water supply. However, the amount of wastewater that can be reclaimed for reuse is subject to many factors, ranging from technical to socio-economic, environmental and institutional. This paper presents two prediction models for wastewater reuse potential in South Africa. The proposed models, namely a Bayesian Network model and a Linear Regression model, were used as a platform for integrated analysis of features such as water use, and socio-demographic and environmental factors. A dataset from the sub-regions of the 19 water management areas in South Africa was employed as input into the models in order to analyse these features and to consequently predict water reuse potential. Keywords: water reuse, wastewater recycling, Bayesian network, linear regression


2013 ◽  
Vol 3 (4) ◽  
pp. 392-401 ◽  
Author(s):  
Nicholas Kathijotes ◽  
Charalambos Panayiotou

Climate change and the continuous population growth increase the demand for water, which in arid and semiarid regions, like the Mediterranean, is considered a limited resource. Future demands will not be met by traditional water resources like surface and groundwater. In order to handle increased water demand, the treated wastewater originating from municipal wastewater treatment plants is offered to farmers for agricultural irrigation. Over pumping of fresh groundwater creates seawater intrusion that causes various problems, besides others, to the quality of recycled water used for agricultural purposes. The effects on soils irrigated with saline water are investigated. Actual investigations were carried out in land irrigated with salinity-affected wastewater and non-irrigated land nearby. Soil profile analyses are demonstrated and compared, showing very interesting results and adverse effects on soil resources. Irrigation with saline waters even at slightly above recommended values can have severe effects on soil resources. Various remediation scenarios for preventing seawater intrusion, as well for mitigation or control of soil salinity problems, are also suggested in this study. This case study was carried in the Larnaca district in Cyprus.


2006 ◽  
Vol 54 (6-7) ◽  
pp. 423-430 ◽  
Author(s):  
E. Friedler ◽  
O. Lahav

Public support is crucial for successful implementation of wastewater reuse projects. This paper analyses the findings of a questionnaire-type survey (256 participants) conducted to determine the attitude of Israeli urban public towards possible urban reuse options. The paper summarises the support / objection to 13 reuse options and the correlation between support and environmental awareness and perceptions. Results show that a high proportion of the participants supported options perceived as low-contact, such as irrigation of public parks (96%), sidewalk landscaping (95%) and use in the construction industry (94%), while higher-contact reuse options found less support (e.g. commercial launderettes, 60%). No correlation was found between biographical characteristics and support (education, gender, income, age). Based on the results, public campaigns in Israel should focus on disseminating information regarding wastewater treatment technologies, discuss health related issues, highlight the positive economic impact of water reuse and generate a positive public opinion, as these factors tend to influence individuals to support reuse projects.


1995 ◽  
Vol 31 (5-6) ◽  
pp. 443-446 ◽  
Author(s):  
P. G. Gaspard ◽  
J. Schwartzbrod

In the framework of agricultural wastewater reuse, the W.H.O. has defined a parasitological quality for sewage with less than one nematode egg per liter. The purpose of this work is to define an effective method to detect helminth eggs in wastewater. Seven techniques have been applied to waste water analysis, with a comparison of their respective results, varying from 26 to 74 %. Be it in the framework of artificial contamination or on site, the best results were obtained with the diphasic technique perfected at the laboratory including a treatment with antiformine at 8 % + ethylacetate followed by a flotation with zinc sulphate at 55%. The validation in the laboratory of the methods performance on treated wastewater allowed us to show that the yield of the method is significantly independent of the egg concentration as well as giving good homogeneity of results with a concentration of 1 egg/litre.


1999 ◽  
Vol 40 (4-5) ◽  
pp. 43-50 ◽  
Author(s):  
Marcelo Juanico ◽  
Eran Friedler

Most of the water has been captured in the rivers of Israel and they have turned into dry river-beds which deliver only sporadic winter floods. In a semi-arid country where literally every drop of water is used, reclaimed wastewater is the most feasible water source for river recovery. Two topics are addressed in this paper: water quality management in rivers where most of the flowing water is treated wastewater, and the allocations of reclaimed wastewater required for the recovery of rivers and streams. Water quality management must consider that the main source of water to the river has a pollution loading which reduces its capability to absorb other pollution impacts. The allocation of treated wastewater for the revival of rivers may not affect negatively the water balance of the region; it may eventually improve it. An upstream bruto allocation of 122 MCM/year of wastewater for the recovery of 14 rivers in Israel may favor downstream reuse of this wastewater, resulting in a small neto allocation and in an increase of the water resources available to the country. The discharge of effluents upstream to revive the river followed by their re-capture downstream for irrigation, implies a further stage in the intensification of water reuse.


Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2004
Author(s):  
Aakash Dev ◽  
Timo C. Dilly ◽  
Amin E. Bakhshipour ◽  
Ulrich Dittmer ◽  
S. Murty Bhallamudi

A transition from conventional centralized to hybrid decentralized systems has been increasingly advised recently due to their capability to enhance the resilience and sustainability of urban water supply systems. Reusing treated wastewater for non-potable purposes is a promising opportunity toward the aforementioned resolutions. In this study, we present two optimization models for integrating reusing systems into existing sewerage systems to bridge the supply–demand gap in an existing water supply system. In Model-1, the supply–demand gap is bridged by introducing on-site graywater treatment and reuse, and in Model-2, the gap is bridged by decentralized wastewater treatment and reuse. The applicability of the proposed models is evaluated using two test cases: one a proof-of-concept hypothetical network and the other a near realistic network based on the sewerage network in Chennai, India. The results show that the proposed models outperform the existing approaches by achieving more than a 20% reduction in the cost of procuring water and more than a 36% reduction in the demand for freshwater through the implementation of local on-site graywater reuse for both test cases. These numbers are about 12% and 34% respectively for the implementation of decentralized wastewater treatment and reuse.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1527
Author(s):  
Mahmoud S. Hashem ◽  
Xue-Bin Qi

As the most important resource for life, water has been a central issue on the international agenda for several decades. Yet, the world’s supply of clean freshwater is steadily decreasing due to extensive agricultural demand for irrigated lands. Therefore, water resources should be used with greater efficiency, and the use of non-traditional water resources, such as Treated Wastewater (TW), should be increased. Reusing TW could be an alternative option to increase water resources. Thus, many countries have decided to turn wastewater into an irrigation resource to help meet urban demand and address water shortages. However, because of the nature of that water, there are potential problems associated with its use in irrigation. Some of the major concerns are health hazards, salinity build-up, and toxicity hazards. The objectives of this comprehensive literature review are to illuminate the importance of using TW in irrigation as an alternative freshwater source and to assess the effects of its use on soil fertility and other soil properties, plants, and public health. The literature review reveals that TW reuse has become part of the extension program for boosting water resource utilization. However, the uncontrolled application of such waters has many unfavorable effects on both soils and plants, especially in the long-term. To reduce these unfavorable effects when using TW in irrigation, proper guidelines for wastewater reuse and management should be followed to limit negative effects significantly.


2021 ◽  
Vol 11 (4) ◽  
pp. 1889 ◽  
Author(s):  
Agnieszka Micek ◽  
Krzysztof Jóźwiakowski ◽  
Michał Marzec ◽  
Agnieszka Listosz ◽  
Tadeusz Grabowski

The results of research on the efficiency and technological reliability of domestic wastewater purification in two household wastewater treatment plants (WWTPs) with activated sludge are presented in this paper. The studied facilities were located in the territory of the Roztocze National Park (Poland). The mean wastewater flow rate in the WWTPs was 1.0 and 1.6 m3/day. In 2017–2019, 20 series of analyses were done, and 40 wastewater samples were taken. On the basis of the received results, the efficiency of basic pollutant removal was determined. The technological reliability of the tested facilities was specified using the Weibull method. The average removal efficiencies for the biochemical oxygen demand in 5 days (BOD5) and chemical oxygen demand (COD) were 66–83% and 62–65%, respectively. Much lower effects were obtained for total suspended solids (TSS) and amounted to 17–48%, while the efficiency of total phosphorus (TP) and total nitrogen (TN) removal did not exceed 34%. The analyzed systems were characterized by the reliability of TSS, BOD5, and COD removal at the level of 76–96%. However, the reliability of TN and TP elimination was less than 5%. Thus, in the case of biogenic compounds, the analyzed systems did not guarantee that the quality of treated wastewater would meet the requirements of the Polish law during any period of operation. This disqualifies the discussed technological solution in terms of its wide application in protected areas and near lakes, where the requirements for nitrogen and phosphorus removal are high.


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