Low-quality Wastewater Research Articles

Impact of wastewaters on groundwater quality of Bani Al-Hareth and Arhab areas in northern Sana’a city, Yemen

The purpose of this research is to determine the impacts of wastewater effluents on groundwater quality of the northern su­­burbs of Sana’a city. Fourteen duplicate groundwater and wastewater samples were collected from the study area and analyzed. The groundwater samples were analyzed for major elements, and anionic and cationic groups using Atomic Absorption Spectrophotometer (AAS). The wastewater samples were analyzed for Total Coliform (TC), Fecal Coliform (FC), and oxygen demands. For characterizing the groundwater and wastewater qualities of the study area, analysis results were tabulated, statistically treated, and elements and ionic groups were graphically plotted on diagrams and on the Piper well known diagram. The analysis results had shown that some groundwater samples were chemically and biologically contaminated. Moreover, the effluent wastewater samples had shown that all samples contain greater Fecal Coliform (FC) bacteria count and high ammonia content. In addition, the effluent wastewaters are featured with high COD and BOD, reflecting low quality wastewater effluent for the WWTP. Sludge and wastewaters used by farmers, containing high pathogens and parasites, have created or will create significant environmental and health hazards. Similarly, land resources, infrastructure and groundwater quality of the areas are highly, if not already, jeopardized or polluted. Such findings require further detailed studies for monitoring development of pollution in the area.

Biotransformation of Low-Quality Wastewater into the Production of Water of Economic Value

In recent years, many countries, especially after the increase in population and agricultural land, suffered from a freshwater shortage. This research obtained the positive role of using biotransformation processes to treat contaminated water and reuse it in agriculture. The results indicated that bioremediation of wastewater by using "bacterial consortium” has a positive effect on reducing some biological and non-biological pollutants. There was excellent potential to decrease pathogenic microbes. In addition, the release of some important compounds during the growth of these bacteria in the developing environments, such as some enzymes, amino acids (1.74-fold), organic acids (20.16-fold), gibbrillic acid (2.5-fold), indole acetic acid (1.8-fold), total carbohydrates (10.8-fold), total lipids (18.3-fold) and total phenols (1.68-fold) compared with control.

Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters

Abstract. The supply of water is limited in some parts of the Mediterranean region, such as southeastern Spain. The use of treated wastewater for the irrigation of agricultural soils is an alternative to using better-quality water, especially in semi-arid regions. On the other hand, this practice can modify some soil properties, change their relationships and influence soil quality. In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. These indices represent the balance reached among properties in "steady state" soils. This study was carried out in four study sites from SE Spain irrigated with wastewater, including four study sites. The results showed slight changes in some soil properties as a consequence of irrigation with wastewater, the obtained levels not being dangerous for agricultural soils, and in some cases they could be considered as positive from an agronomical point of view. In one of the study sites, and as a consequence of the low quality wastewater used, a relevant increase in soil organic matter content was observed, as well as modifications in most of the soil properties. The application of soil quality indices indicated that all the soils of study sites are in a state of disequilibrium regarding the relationships between properties independent of the type of water used. However, there were no relevant differences in the soil quality indices between soils irrigated with wastewater with respect to their control sites for all except one of the sites, which corresponds to the site where low quality wastewater was used.

Estrogen mimicking effects of xenobiotics in fish

Sex hormones produced in humans and livestock are excreted in the urine. Naturally produced and synthetic contraceptive pill estrogens may pass low-quality waste water processing plants and feminize male fish in streams and coastal areas downstream such discharges [1,2]. High-quality processing of the wastewater with tertiary treatment, nutrient removal and sufficient water and sludge retention times basically removes the problem [3,4]. The feminization of male fish downstream waste water discharges has mainly been demonstrated by the presence of elevated levels of female yolk protein (vitellogenin) in the blood of male or juvenile fish or eggs (or oocytes) in the testes (intersex) [5]. Both of these phenomena are used as biomarkers for estrogenic effects and as always in the use of biomarkers, it is important to define the natural background level in an uncontaminated environment. The first investigations on intersex in roach showed that male fish in areas not directly affected by wastewater discharges had intersex percentages between 5 and 11% [1,6], suggesting that there might be a low, natural occurrence of this phenomenon. Recent investigations [7] in pristine areas do, however, show no intersex among the males, indicating that the natural background level of intersex roach may actually be zero. Plasma levels in male or juvenile fish have been used as an efficient biomarker to detect estrogenic contamina-tion in both freshwater and marine areas and a number of studies [e.g. [8,9]] have presented vitellogenin levels that are markedly and unambiguously elevated - maybe several orders of magnitude - compared to background levels. Less effort has been devoted to defining when less severe increases in plasma vitellogenin levels actually indicate a difference relative to unaffected background levels [10]. The occurrence of intersex in roach and elevated vitellogenin levels in areas not directly affected by discharges from sewage treatment plants suggests that there may be other inputs of estrogenic activity to the aquatic environment and, in fact, several possibilities – some of them associated with intensive, modern agriculture - exist. Estrogens have been found to leach to the water draining from fields treated with pig manure [11], which generally has a high content of especially estrone and estrogenic activity has been found in streams in connection with dairy cattle farms [12]. Leguminous plants - such as clover, peas, lupine and alfalfa used as nitrogen binding crop in e.g. organic farming - produce phytoestrogens which may leach to - and are detected in - the freshwater environment [13] – most often in the ng/l range. Some phytoestrogens induce vitellogenin synthesis in the low µg/l range [14]. Houses in the open land are not all connected to central sewage treatment plants and simple waste water processing measures such as septic tanks may be employed. Septic tanks do a very poor job removing estrogens from wastewater and estrogenic activities 20 times higher than needed to feminize brown trout have been detected in discharges from such systems [15]. Recently, exposure to 17β-estradiol and octylphenol has been shown to cause malformations in embryos of viviparous eelpout at fairly high – but still environmentally realistic concentrations [16].

Longevity of soil water repellency in a former wastewater disposal tree stand and potential amelioration

Previous studies have shown that long-term irrigation with wastewater can lead to the development of soil water repellency. Little is known about the longevity of this effect. Here we address this research gap by examining the effect of long-term (~ 20 years) use of low-quality wastewater for disposal purposes, followed by 6 years of ‘recovery’ with no irrigation, on the wettability of calcareous sandy soil (Xerofluvent) under a Populus alba tree stand used as a “green filter” in SE Spain. Water repellency (WR) and soil organic matter content (SOM) were determined for 120 air-dry samples from the plot and 80 control samples from adjacent and otherwise similar non-irrigated areas. To account for plot micro-topography 40 samples each were taken from ridges (R; 0–5 cm depth), furrows (F; 0–5 cm), and furrows at depth (FD; 5–10 cm). The controls included 40 samples each (0–5 cm depth) from unvegetated and unploughed soil, and from soil under the P. alba plantation. All control samples were non-repellent whereas at the irrigated plot, water repellency was present for 48, 95 and 93% of ridge, furrow and furrow-depth samples respectively. WR and SOM was strongly correlated within the whole sample population (R 2 = 0.623**) and within two sample groups (R: R 2 = 0.783**; FD: R 2 = 0.424**), but weakly within F samples (R 2 = 0.072 n.s.). The latter showed the highest frequency and persistence (WDPT) of WR, indicating that not only quantity of SOM is controlling WR. Exploratory kaolinite clay additions (0.5–8%) to samples substantially reduced WR even at the lowest concentration, indicating that this could be a promising amelioration treatment for the WR in the soils investigated here. We conclude that for the conditions studied here (i) long-term use with poor-quality wastewater for disposal had led to the development of soil WR, (ii) a 6-year period of ‘recovery’ (i.e. non-irrigation) was insufficient to eliminate the induced WR, and (iii) kaolinite addition could be a promising amelioration treatment for these sandy soils.

The Yuma desalting plant and Cienega de Santa Clara dispute: a case study review of a workgroup process

Despite progress in international water management in recent decades, innovative methods for ongoing collaborative decision making are still needed to resolve and avoid disputes over transboundary waters. One such conflict is over the operation of the Yuma Desalting Plant (YDP) in Arizona, which has implications for the Cienega de Santa Clara, a recently formed downstream wetland in Mexico. Although treaties have been negotiated in the past to govern the quantity and quality of Colorado River water entering Mexico from the USA, renewed interest in reclaiming low quality wastewater in the context of a long-run drought has sparked a new conflict over developing this water supply for human use or maintaining the flows for ecosystem protection. The formation of a problem-focused workgroup, unofficially representing a range of interested parties, is reviewed as a creative, complementary solution to address this dispute. Specific strengths and limitations of the approach are discussed within the broader context of managing international waters. While the workgroup shows innovation as a collaborative process for conflict resolution, the lack of an open, transparent process and the exclusion of Mexico threaten the successful resolution of the YDP dispute and potential future conflicts over transboundary waters.

Irrigation of olive groves in Southern Italy with treated municipal wastewater: Effects on microbiological quality of soil and fruits

The use of municipal wastewater in agriculture requires a careful monitoring of a range of hygiene parameters. Yearly hygienic impact assessments on soil and fruit were made between 2000 and 2006 in an olive ( Olea europaea L.) grove established near a municipal wastewater treatment plant in Southern Italy (Ferrandina–Basilicata region, 40°29′ N, 16°28′ E). The experimental grove was managed in two plots. The first plot, non-tilled, was drip irrigated daily with reclaimed wastewater. The second plot was unirrigated (i.e. rainfed) and subject to conventional management for the region. Samples of wetted soil from different depths and of treated wastewater were analysed for Escherichia coli, enterococci, sulphite-reducing Clostridium spores and Salmonella spp. Fruits were collected both from the canopy and from nets spread on the ground and analysed for faecal contamination. The average annual quantity of wastewater distributed was 293 mm. E. coli concentration in the wastewater varied considerably, being frequently above the stringent Italian mandatory limit of 10 CFU 100 mL −1 and also the WHO limit of 1000 MPN 100 mL −1. Salmonella was never detected in the wastewater, the soil or on the fruit samples. Slight increases in the other bacteria were observed in the wastewater-irrigated soil during the irrigation season and especially in the top 10 cm. Soil resilience and bacterial mortality/inactivation probably explains the seasonal decrease of soil bacteria content over the 7 years of the study. Because of their high resistance to disinfection treatments and to environmental conditions, the spores of the sulphite-reducing bacterium Clostridium could be useful as an indicator of contamination in future guidelines that might be enacted for the use of wastewater in agriculture. No significant microbial contamination was recorded on fruit harvested directly from the canopy of the wastewater-irrigated trees. Contaminations on fruits sampled from the ground in the wastewater-irrigated plot were always low and usually similar to, or lower than those observed on drupes collected from the rainfed plot. In the rainfed plot, the recorded occasional contaminations were probably due to a number of factors, such as grazing of farm stock, presence of wild animals and surface water runoff from adjacent agricultural areas. This work confirms that, under suitable conditions, low-quality wastewater can be useful as an additional water resource for olive irrigation in water-scarce Mediterranean environments.

Effect of Evapotranspiration on the Salinity of Wastewater Treated By Aquatic Plants

The shortage of good quality water resources is becoming an important issue in arid and semi-arid zones. Irrigation systems must be developed that are capable of delivering low quality wastewater while taking into account environmental and health requirements. For this reason, the availability of water resources of marginal quality, such as desalinated wastewater, can be a significant contribution to the water supply. We investigated changes in salinity, in conjunction with evaporation kinetics of treated wastewater by aquatic plants. These plants enhance the removal of pollutants by consuming them in the form of plant nutrients and through the microbial activity on their roots. In particular, this treatment applies to urban and agricultural sewage, where treatment units of different sizes can be applied at the pollution source while acting as green environments. In these treatment units, increased salinity due to effect of evapotranspiration (ET) must be managed. The rates of evaporation (E) from the free water surface and transpiration (T) from the plants were determined under field and laboratory conditions. To this end, batch experiments were performed with floating and emergent aquatic plants. After 4 days in the presence of floating plants, the biochemical oxygen demand (BOD) decreased from its 100-110 mg L(-1) initial value down to 30-40 mg L(-1) (65% to 70% removal), concurrent with a 2% to 5% increase in the chlorides level, and 5% to 8% in the electroconductivity. The ET rates were found to be a significant factor in the water balance governing the treatment process. The results of this work provide guidelines for recommended wastewater treatment times that safeguard against undesirable rises in salinity, yet with marginal change in parameters such as BOD. The change of salinity is shown to be relatively minor in the first days of treatment where the change in BOD is faster, whereas in the following days the picture is reversed. This result indicates the advantage of applying shorter treatment periods when the rise in salinity is avoided.

Low Quality Wastewater UV Disinfection at Sand Island WWTP Part 2 - Reactor Design, Pilot Testing, and Full Scale Performance Tests

Low Quality Wastewater UV Disinfection at Sand Island WWTP Part 2 - Reactor Design, Pilot Testing, and Full Scale Performance TestsUltraviolet (UV) light is used for disinfecting many types of waters including low quality waters like primary treated wastewaters and combined sewer overflows. Low quality waters are often thought to be challenging for UV because they have low UV transmittance (UVT), but with the proper reactor design, UV can be successfully applied. UV has now been installed at the Sand Island WWTP in Hawai'i,...Author(s)Brian PetriSourceProceedings of the Water Environment FederationSubjectSession 50: Validation of UV Reactors: New Approaches to Consistent UV DesignDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2008ISSN1938-6478SICI1938-6478(20080101)2008:13L.3865;1-DOI10.2175/193864708788733198Volume / Issue2008 / 13Content sourceWEFTECFirst / last page(s)3865 - 3868Copyright2008Word count172

Low-Quality Wastewater UV Disinfection at Sand Island WWTP Part 1 - Bench-Scale Evaluation and First-Year Operation

Low-Quality Wastewater UV Disinfection at Sand Island WWTP Part 1 - Bench-Scale Evaluation and First-Year Operation