Effects Of Wastewater Discharges Research Articles

Wastewater discharges alter microbial community composition in surface waters of the canadian prairies

Microbial communities are an important component of freshwater biodiversity that is threatened by anthropogenic impacts. Wastewater discharges pose a particular concern by being major sources of anthropogenic contaminants and microorganisms that may influence the composition of natural microbial communities. Nevertheless, the effects of wastewater treatment plant (WWTP) effluents on microbial communities remain largely unexplored. In this study, the effects of wastewater discharges on microbial communities from five different WWTPs in Southern Saskatchewan were investigated using rRNA gene metabarcoding. In parallel, nutrient levels and the presence of environmentally relevant organic pollutants were analyzed. Higher nutrient loads and pollutant concentrations resulted in significant changes in microbial community composition. The greatest changes were observed in Wascana Creek (Regina), which was found to be heavily polluted by wastewater discharges. Several taxa occurred in greater relative abundance in the wastewater-influenced stream segments, indicating anthropogenic pollution and eutrophication, especially taxa belonging to Proteobacteria, Bacteroidota, and Chlorophyta. Strong decreases were measured within the taxa Ciliphora, Diatomea, Dinoflagellata, Nematozoa, Ochrophyta, Protalveolata, and Rotifera. Across all sample types, a significant decline in sulfur bacteria was measured, implying changes in functional biodiversity. In addition, downstream of the Regina WWTP, an increase in cyanotoxins was detected which was correlated with a significant change in cyanobacterial community composition. Overall, these data suggest a causal relationship between anthropogenic pollution and changes in microbial communities, possibly reflecting an impairment of ecosystem health.

Effects of Wastewater Discharge on Antibiotic Resistance Genes and Microbial Community in a Coastal Area

Wastewater treatment plants (WWTPs) are important sources of antibiotic resistance genes (ARGs) in aquatic environments. Mobile genetic elements (MGEs) and microbial communities are key factors that affect the proliferation of ARGs. To reveal the effects of WWTPs effluent discharge on the ARGs and microbial community in a coastal area, the structure and distribution of ARGs, MGEs, and microbial community in Shangyu (SY) and Jiaxing (JX) effluent receiving areas (ERAs) and the offshore area of Hangzhou Bay (HB) were investigated via high-throughput quantitative PCR and 16S rRNA high-throughput sequencing. The results showed that multidrug resistance genes were the most abundant ARGs across all the sampling sites. The diversity and abundance of ARGs and MGEs in the ERAs were much higher than those in the HB. Additionally, the diversities of the microbial community in the JX-ERA were higher than those in the SY-ERA and HB. PCoA showed that the distribution of ARGs, MGEs, and microbial communities in the ERAs and HB were significantly different, indicating that the long-term wastewater discharge could alter the distribution of ARGs, MGEs, and microbial communities in the coastal area. The co-occurrence pattern among ARGs, MGEs, and microbial communities revealed that 12 bacterial genera, such as Psychrobacter, Pseudomonas, Sulfitobacter, Pseudoalteromonas, and Bacillus, showed strong positive correlations with ARGs and MGEs. Most potential hosts carried multidrug and β-lactamase resistance genes.

Effect of Wastewater Discharge From Coffee Processing Plant on River Water Quality, Sidama Region, South Ethiopia.

In Ethiopia, most of the coffee processing plants are generating large amounts of wastewater with high pollutant concentrations and discharge directly into the water bodies untreated or partially treated. The main objective of this study was to assess the effects of coffee wastewater discharged to river water quality using physicochemical parameters and macro-invertebrate indices. This study was conducted from November to the end of December 2019. Ten wastewater and river water samples were taken from coffee the processing plant and river. The macro-invertebrate samples were collected by kick sampling technique using a standard hand net. Shannon and Simpson diversity indices were examined at 3 sampling stations. The Pielou evenness index was also determined. It was found that except for TDS all the parameters of the raw wastewater and river water did not comply with the international discharge limit. The mean concentration of Faro coffee processing plant wastewater were BOD5 (2409.6 ± 173.1 mg/L), COD (4302 ± 437 mg/L), TSS (2824.6 ± 428.4 mg/L), TDS (3226 ± 623.6 mg/L), and TS (4183.3 ± 432.9 mg/L). Whereas from Bokaso coffee processing plant were BOD5 (3770 ± 604.4 mg/L), COD (4082.6 ± 921.9 mg/L), TSS (2766 ± 501.7 mg/L), TDS (3017 ± 747.6 mg/L), and TS (3874 ± 471.1 mg/L). A total of 392 macroinvertebrates belonging to 24 families and 7 orders were collected. The benthos assemblage communities in this river were 40, 56, and 296 at downstream 1, downstream 2, and upstream respectively. The value of the Simpson diversity index varies from 0.4 to 0.75. In the same manner, the value of the Shannon diversity index also varied from 0.5 to 1.36. Most of the physicochemical parameters of the raw wastewater were beyond the national and international discharge limits. The quality of Orsha river water downstream was more adversely affected compared to upstream.

Acidity, Electric Conductivity, Dissolved Oxygen Total Dissolved Solid and Salinity Profiles of Marine Water in Gaza: Influence of Wastewater Discharge

Effects of wastewater discharge on the coastal area in Gaza strip Palestine are not fully investigated. This study investigated the effect wastewater discharge of the physical and chemical properties of marine water in the coastal area over a period of 2 year. Sea water and sediment samples were collected from about 20 different sites. The water and the sediments were collected wastewater/sea water mixing zone at depth 0, 2.5 and 5 m water column depth at a direct wastewater discharging pipe line from different location and similarly from other locations. Water temperature T, electric conductivity (EC), dissolved oxygen (DO), pH, total dissolved solid (TDS) and salinity were determined for water samples using field equipment such as pH-meter, DO meter, TDS-/ and EC-meter. On the other hand, NO3-, SO42-, PO43- were determined in the laboratory using chemical methods, details are described in materials and method section. Results showed average and standard deviation of T, EC, DO, pH, TDS and salinity were 22.02°C ± 4.1°C, EC: 58.41 ± 4.8 ms/cm; DO: 6.96 ± 1.8 mg/L; pH: 7.69 ± 0.37; TDS: 30.51 ± 3.29 and salinity 4.39 ± 0.12 (%); whereas, average and standard deviation of NO3-: were 299.8 ± 204.1 mg/L; SO42-, 5736.9 ± 817.1; and PO43-: 164.35 ± 120.7 mg/L. The measured values indicate significant differences due to high value of standard deviation of some measured parameters. This indicates the influence of wastewater discharge in sea water as shown inside the manuscript in the appropriate section. The study recommends efficient treatment of wastewater and reuses it for agricultural purposes instead of discharging it in sea.

Evidence that watershed nutrient management practices effectively reduce estrogens in environmental waters

We evaluate the impacts of different nutrient management strategies on the potential for co-managing estrogens and nutrients in environmental waters of the Potomac watershed of the Chesapeake Bay. These potential co-management approaches represent agricultural and urban runoff, wastewater treatment plant effluent, and combined sewer overflow replacements. Twelve estrogenic compounds and their metabolites were analysed by gas chromatography–mass spectrometry. Estrogenic activity (E2Eq) was measured by in vitro bioassay. We detected estrone E1 (0.05–6.97 ng L−1) and estriol E3 (below detection-8.13 ng L−1) and one conjugated estrogen (estrone-3-sulfate E1-3S; below detection-8.13 ng L−1). E1 was widely distributed and positively correlated with E2Eq, water temperature, and dissolved organic carbon (DOC). Among nonpoint sources, E2Eq, and concentrations of E1, soluble reactive phosphorus (SRP) and total dissolved nitrogen (TDN) decreased by 51–61%, 77–82%, 62–64%, 4–16% in restored urban and agricultural streams with best management practices (BMPs) relative to unrestored streams without BMPs. In a wastewater treatment plant (Blue Plains WWTP), >94% of E1, E1-3S, E3, E2Eq and TDN were removed while SRP increased by 305% during nitrification/denitrification as a part of advanced wastewater treatment. Consequently, E1 and TDN concentrations in WWTP effluents were comparable or even lower than those observed in the receiving stream or river waters, and the effects of wastewater discharges on downstream E1 and TDN concentrations were minor. Highest E2Eq value and concentrations of E1, E3, and TDN were detected in combined sewer overflow (CSO). This study suggests that WWTP upgrades with biological nutrient removal, CSO management, and certain agricultural and urban BMPs for nutrient controls have the potential to remove estrogens from point and nonpoint sources along with other contaminants in streams and rivers.

Effects of pollution on marine organisms.

This review covers selected 2019 articles on the biological effects of pollutants, including human physical disturbances, on marine and estuarine plants, animals, ecosystems, and habitats. The review, based largely on journal articles, covers field, and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing, and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, marine debris, dredging, and disposal. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico and proliferation of data on the assimilation and effects of marine debris microparticulates. Several topical areas reviewed in the past (e.g., mass mortalities ocean acidification) were dropped this year. The focus of this review is on effects, not on pollutant sources, chemistry, fate, or transport. There is considerable overlap across subject areas (e.g., some bioaccumulation data may be appeared in other topical categories such as effects of wastewater discharges, or biomarker studies appearing in oil toxicity literature). Therefore, we strongly urge readers to use keyword searching of the text and references to locate related but distributed information. Although nearly 400 papers are cited, these now represent a fraction of the literature on these subjects. Use this review mainly as a starting point. And please consult the original papers before citing them.

Effects of pollution on marine organisms.

This review covers selected 2018 articles on the biological effects of pollutants, including human physical disturbances, on marine and estuarine plants, animals, ecosystems, and habitats. The review, based largely on journal articles, covers field and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing, and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, marine debris, dredging, and disposal. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico and proliferation of data on the assimilation and effects of marine debris. Several topical areas reviewed in the past (e.g., mass mortalities ocean acidification) were dropped this year. The focus of this review is on effects, not on pollutant sources, chemistry, fate, or transport. There is considerable overlap across subject areas (e.g., some bioaccumulation data may be appear in other topical categories such as effects of wastewater discharges, or biomarker studies appearing in oil toxicity literature). Therefore, we strongly urge readers to use keyword searching of the text and references to locate related but distributed information. Although nearly 400 papers are cited, these now represent a fraction of the literature on these subjects. Use this review mainly as a starting point. And please consult the original papers before citing them.

Effects of Pollution on Marine Organisms.

This review covers selected 2017 articles on the biological effects of pollutants and human physical disturbances on marine and estuarine plants, animals, ecosystems and habitats. The review, based largely on journal articles, covers field and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, marine debris, dredging and disposal etc. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico and proliferation of data on the assimilation and effects of marine debris microparticulates. Several topical areas reviewed in the past (e.g.mass mortalities ocean acidification) were dropped this year. The focus of this review is on effects, not on pollutant sources, chemistry, fate or transport. There is considerable overlap across subject areas (e.g.some bioaccumulation data may be appear in other topical categories such as effects of wastewater discharges, or biomarker studies appearing in oil toxicity literature). Therefore, we strongly urge readers to use keyword searching of the text and references to locate related but distributed information. Although nearly 400 papers are cited, these now represent a fraction of the literature on these subjects. Use this review mainly as a starting point. And please consult the original papers before citing them.

Identification of significant pressures and assessment of wastewater discharge on Krivaja River water quality

One of the key stages of the process of preparing management plans for the river basin is the analysis of pressures and impacts, as well as the risk assessment of failing to achieve the environmental objectives. DPSIR framework (Driving Forces-Pressure-State-Impact-Response) was developed by the European Agency for the environmental protection, and makes the conceptual basis for the pressures and impacts analysis, taking into account the complexity of the interactions in the environment and represents the tool for their analysis. Impact assessment of the water body requires some quantitative information to describe the condition of the water body and/or the pressures that act on it. The aim of the study was to determine the effect of wastewater discharge on Krivaja watercourse. Impact assessment is carried out based on data of polluters? wastewater and monitoring information for water in Krivaja. For each site at which sampling was performed, the specific risk quotients for surface water were calculated, as the ratio of the each pollutant concentration in surface water at the sampling point and environmental quality standards for pollutants, as well as their sum that represents the risk index. In order to have the integrated perceive of processes in the Krivaja River, taking into account cumulative effects from point sources, the concept of total maximum daily load was applied, using which the pollution amount, that can be discharged daily in a water body without degrading his prescribed/required quality, was calculated. Comparison of emitted loads from pollution point sources with maximum allowable ones was performed. Wastewaters of different polluters located on Krivaja are, due to insufficient treatment, very loaded with organic matter and nutrients. Krivaja receives daily 1332 m3 of wastewater, 999 kg COD, 722 kg BOD, 144 kg of nitrogen, 4.3 kg of phosphorus and 627 kg of suspended solids. Of the total wastewater volume, the majority (69%) originates from municipal wastewater, 81% of the total amount of organic matter comes from the industry, while nutrients mostly originate from municipal wastewater. Loading of Krivaja with wastewater is major, uneven and unbalanced. Water quality of Krivaja is unsatisfactory. According to national legislation there is the exceedance of maximum permissible values for Class II for watercourse (good status) for most parameters, in all sampling locations and in both sampling periods. Parameters that exceeded the value for the Class II are dissolved oxygen, organic matter content, suspended solids, nutrients. Water flow in the river is not sufficient to receive the total amount of the pollutant load from point sources. Risk assessment, based on the monitoring results, indicates that the river Krivaja is possibly at risk of failing to meet the required water quality because the most of the values exceeded the limit values.

Assessment of environmental impacts of the semi-intensive tilapia culture system

O principal objetivo do presente estudo é avaliar as características físicas, químicas e bacteriológicas dos efluentes contínuos e da despesca de peixes como a tilápia (Oreochromis niloticus), analisar os possíveis impactos das descargas de águas residuais e propor alternativas para minimizar os seus efeitos. As amostras foram coletadas entre abril e outubro, abrangendo assim todo o ciclo de desenvolvimento de tilápia. A demanda de oxigênio dissolvido é a principal causa de problemas ambientais, mas o índice de eutrofização é baixo, apesar de apresentar consideráveis níveis de fósforo total em comparação com os padrões legais estabelecidos pela Resolução 357/05 do Conselho Nacional do Meio Ambiente do Brasil (CONAMA). O índice de pressão ambiental elevou-se a 2,47, o que reforça a necessidade de medidas que possam minimizar esse impacto. A utilização de águas residuais na irrigação é a melhor alternativa, resultando em uso racional da água, menores taxas de utilização de fertilizantes e redução da poluição hídrica.

Effect of wastewater discharge on Jiangsu coastal environment, China

ABSTRACT Ji, H., Pan, S. and Han, X., 2012. Effect of wastewater discharge on Jiangsu coastal environment, China To meet the needs of the rapid economic development in the coastal area of Qidong City in Jiangsu Province of China, a new wastewater treatment plant and a reclaimed water plant have been planned. The preliminarily treated wastewater will be discharged to the coastal area in the Yellow Sea near Dayang Port. Due to the complex tidal regime in the area, the impacts of the outfall from the treatment plant can be important for the surrounding marine environment. The present study aims to investigate the impacts of the discharge of the treated wastewater into the Yellow Sea under three operational conditions using the TELEMAC software. The computational domain covers a large coastal area (~2800 km2). TELEMAC2D is used to compute the depth-averaged currents, and the convection and diffusion of the pollutants, namely CODMn and Inorganic Nitrogen, which are treated as the neutral buoyancy tracers, but ...

Microcrustacean assemblages in a large river: on the importance of the flow regime

Microcrustacean plankton was sampled in the Danube River just upstream and downstream of Budapest, a large city with considerable industrial and municipal discharges. I addressed the questions of whether (i) there is any longitudinal variation in the densities and community attributes of microcrustaceans, and (ii) how these relate to river flow and nutrient discharges. Microcrustacean densities and diversities varied significantly between upstream and downstream sites as well as between different hydrological phases. Densities recorded in high water upstream were comparable to those recorded downstream, densities in low water, however, were considerably higher downstream. High water was associated with increased densities and diversities. The number and relative abundance of tychoplanktonic species considerably increased in high water. All those findings suggest the importance of downstream transport from adjacent water bodies. Diversities did not experience a downstream decline, and the effects of waste water discharges cannot be detected irrespective of the flow regime. The results indicate that effects of waste waters are embedded within the river flow effect in such a way that the latter appears to mask the impact of nutrient loads. This study provides further evidence for the flow regime as a major driver of biodiversity in floodplain rivers.

Effect of wastewater discharge on greenhouse gas fluxes from mangrove soils

Abstract The effects of wastewater on atmospheric fluxes of three greenhouse gases, nitrous oxide (N 2 O), methane (CH 4 ) and carbon dioxide (CO 2 ) from mangrove soils were investigated, and the differences among shrimp pond wastewater (SP), livestock wastewater (LS) and municipal (S) sewage were compared. The gas emissions from mangrove soils were significantly enhanced after wastewater irrigation and the highest emission of N 2 O and CO 2 were obtained from SP. High N 2 O emission was also found in S treatment, where fluxes varied from 13.42 to 16.78 μmol m −2 h −1 , but the CH 4 and CO 2 fluxes were as low as the control irrigated with tap water. Results of soil analyses indicated that the high N 2 O emissions from mangrove soils receiving SP and S treatments were attributed to the denitrification and nitrification processes, respectively. The highest CH 4 flux was recorded in LS treatment (186.14–762.40 μmol m −2 h −1 ), which also had the highest CO 2 flux. The fluxes measured during the non-irrigation period were lower than those measured 4 h after irrigation.

Effect of Wastewater Discharge on Root Anatomy and Radial Oxygen Loss (ROL) Patterns of Three Mangrove Species in Southern China

The effects of wastewater discharge on radial oxygen loss (ROL) and root anatomy varied among mangrove species. ROL of Bruguiera gymnorrhiza (L.) increased from 22.44 ng cm−2 min−1 in the control (just fresh water) to 31.09 ng cm−2 min−1 when received normal wastewater (NW) and to 44.22 ng cm−2 min−1 when treated with strong wastewater (10NW). However, discharge of both NW and 10NW caused 28% decreases of ROL in the root tip of Excoecaria agallocha L., and the decreases in Acanthus ilicifolius L. were even more significant, with 45% when treated by 10NW. The changes of ROL were related to the root anatomy. Among three species, A. ilicifolius had the highest proportional cross-sectional area of aerenchyma air spaces, suggesting that the internal oxygen transfer to root tip was the fastest. However, the area of aerenchyma air spaces in the root tip of 10NW treated A. ilicifolius was significantly reduced while area of epidermis and hypodermis (E+H) increased leading to less oxygen supply to root tip. Compared to B. gymnorrhiza and E. agallocha, the (E+H) layer of A. ilicifolius was the thinnest, and the cells without suberized walls were loosely packed in all three treatments. These results suggested that the root anatomy and ROL of B. gymnorrhiza was least affected by wastewater discharge, followed by E. agallocha, and A. ilicifolius was the most susceptible species thus was not suitable for treating strong wastewater.

The effects of wastewater discharges on the functioning of a small temporarily open/closed estuary

Wastewater discharges affect the functioning of small temporarily open/closed estuaries (TOCEs) through two main mechanisms: (1) they can significantly change the water balance by altering the quantity of water inflows, and (2) they can significantly change the nutrient balance and hence the water quality. This study investigated the bio-physical responses of a typical, small TOCE on the east coast of South Africa, the Mhlanga Estuary. This estuary receives significant inflows of treated effluent from upstream wastewater treatment works. Water and nutrient budgets were used together with biological sampling to investigate changes in the functioning of the system. The increase in inflows due to the effluent discharges has significantly increased the mouth breaching frequency. Furthermore, when the mouth closes, the accumulation of nutrients leads to eutrophication and algal blooms. A grey water index, namely the proportion of effluent in the estuary and an indicator of the additional nutrient inputs into the estuary, reached high values (≳50%) during low flow regimes and when the mouth was closed. In these hyper-eutrophic conditions (DIN and DIP concentrations up to 457 μM and 100 μM respectively), field measurements showed that algal blooms occurred within about 14 days following closure of the mouth (chlorophyll-a concentrations up to 375 mg chl-a m −3). Water and nutrient balance simulations for alternative scenarios suggest that further increases in wastewater discharges would result in more frequent breaching events and longer open mouth conditions, but the occurrence of hyper-eutrophic conditions would initially intensify despite more frequent openings. The study indicates how water and nutrient balance simulations can be used in the planning and impact assessment of wastewater treatment facilities.

Wastewater discharge degrades coastal waters and reef communities in southern Thailand

Runoff and sewage discharge from land developments can cause significant changes in water quality of coastal waters, resulting in coral degradation. Coastal waters around Phuket, Thailand are influenced by numerous sewage outfalls associated with rapid tourism development. Water quality and biological monitoring around the Phuket region was undertaken to quantify water quality and biotic characteristics at various distances from sewage outfalls. The surveys revealed strong gradients in water quality and biotic characteristics associated with tourism concentration levels as well as seasonal variability. Water and reef quality tended to decrease with increasing tourist intensity, but improved with increasing distance from sewage discharge within each of the three study locations. In addition, the effect of wastewater discharge was not localised around the source of pollution, but appeared to be transported to non-developed sites by currents, and exacerbated in the wet season.

Effects of wastewater discharge on formation of Fe plaque on root surface and radial oxygen loss of mangrove roots

Effects of wastewater discharge on radial oxygen loss (ROL), formation of iron (Fe) plaque on root surface, and their correlations in Bruguiera gymnorrhiza (L.) Poir and Excoecaria agallocha L. were investigated. ROL along a lateral root increased more rapidly in control than that in strong wastewater (with pollutant concentrations ten times of that in municipal sewage, 10NW) treatment, but less Fe plaque was formed in control for both plants. For B. gymnorrhiza receiving 10NW, Fe plaque formation was more at basal and mature zones than at root tip, while opposite trend was shown in E. agallocha. At day 0, the correlation between ROL and Fe plaque was insignificant, but negative and positive correlations were found in 10NW and control, respectively, at day 105, suggesting that more ROL was induced leading to more Fe plaque. However, excess Fe plaque also served as a ‘barrier’ to prevent excessive ROL in 10NW plants.

Municipal Wastewater Characteristics of Sylhet City, Bangladesh

Research Report: Municipal Wastewater Characteristics of Sylhet City in Bangladesh Raquibul Alam Mushtaq Ahmed Md. Aktarul Islam Chowdhury Shah Jalal University of Science & Technology, Sylhet, Bangladesh Suman Kanti Nath Dhaka, Bangladesh An understanding of the nature of wastewater is essential in the design and operation of collection, treatment, and disposal facilities and in the engineering management of environmental quality. Municipal wastewater of Sylhet city, divisional city of the northeastern region of Bangladesh, originates from different types of sources and then falls into the Surma River through different channels. Malni Chara, the largest channel falling into the Surma River originating from a hilly tea garden was selected for the study. In this study, physical parameters (total solids, dissolved solids, suspended solids, pH) and chemical parameters (BOD, alkalinity, DO, chlorides, nitrates, oil and grease) of wastewater were measured. Maximum value of total solids was found in the Stadium area (600mg/l). pH was found to be almost the same at every point (around 6.5). Maximum nitrates and chlorides were found in Subid Bazar (0.2 mg/L) and the Stadium area (42 mg/L) respectively. The findings of the study conclude that the quality of the wastewater of Sylhet city is medium for suspended solids, BOD 5 and chlorides, and strong for alkalinity. Introduction Sylhet city has been taken as our study area, which is an important divisional city located in the northeastern part of Bangladesh (Latitude: 24.85o N, Longitude: 91.80o E). Sylhet Municipality was established in 1878.The area of the town is 10.49 sq. km. It has a population of 285,308; density of population is 27,198 per sq km (Banglapedia, 2006). The city is situated beside the Surma River. The wastewater effluent from Sylhet city discharged to the Surma River is polluting the river water, as treatment facilities are not yet established in Sylhet. As the quality of wastewater is not satisfactory, problems like pollution of the Surma River and the streams, deterioration of the environment, and health sanitation have become serious. Obviously it is necessary to evaluate the wastewater discharge and disposal system in order to determine the effects of wastewater discharges on receiving water or the public sewer or on any proposed treatment process and to explore possible treatment process requirements to eliminate such

The effect of wastewater discharge on biomass production and nutrient content of Cyperus papyrus and Miscanthidium violaceum in the Nakivubo wetland, Kampala, Uganda

The nutrient content of representative plant parts and biomass production in the Nakivubo wetland, correlation of these with the wastewater flow patterns and determination of nutrient uptake, storage and biomass production of Cyperus papyrus (papyrus) and Miscanthidium violaceum was studied. On average papyrus vegetation under the influence of wastewater had higher nutrient content in the above ground biomass (1.6% N and 0.23% P on dry weight basis) than those not affected (0.98% N and 0.18% P). The biomass varied between 3,529-5,844 g/m2 and 883-1,156 g/m2 in the two respective sites. The juvenile plants of papyrus and Miscanthidium had higher concentrations of P and N in their organs compared to the mature ones. Considering the nutrients stored by the dominant vegetation and the current flow patterns of wastewater in the Nakivubo wetland, harvesting of the above ground biomass once a year, would remove 7.7% of the N input and 15.8% of the P input of the annual total load entering the wetland. However, if the wetland is bio-manipulated and the wastewater flow distributed over the whole wetland, up to 70% nitrogen and 76% phosphorus would be removed by harvesting above ground papyrus biomass.

Characterization of sediment biofilms in stressed sites in a lotic ecosystem in the Rift Valley Province, Kenya

The relationship between sediment biofilm components and anthropogenic activities in the Njoro River, a Kenyan Rift Valley stream, was elucidated by sampling three sites (Mugo, Egerton Bridge & Canning Factory). The concentrations of total organic carbon, total nitrogen, total proteins, total carbohydrates, colloidal carbohydrates and microbial exopolymer carbohydrates were higher in the sediments at Egerton Bridge than in the other sites. Variability of the concentrations of the biofilm components in the three sites was a result of different forms of pollution and natural inputs into the stream. Biofilm esterase activity, measured as fluoroscein diacetate (FDA) hydrolysis rate, was significantly different among the three sites. Post-hoc comparisons using Scheffe's multiple range test (α=0.05) indicated that the amounts of FDA in Canning Factory sediments were significantly lower than those of Egerton Bridge and Mugo. These data suggest that wastewater effluent enhanced biofilm development as evidenced by the high quantities of biofilm components at Egerton Bridge, a site previously exposed to wastewater discharge from nearby lagoons. We speculate that the high quantities of colloidal and exopolymeric substances in the Njoro River were as a result of the high nutrient loading. This ecological study is the first one for a Kenyan stream, and thus provides baseline data for interpreting related ecological studies. There is need for a long term study to elucidate fully the effects of wastewater discharge on biofilm development in streams.