scholarly journals The efficacy of a recovered wash water plant in removing cyanobacteria cells and associated organic compounds

2020 ◽  
Vol 20 (5) ◽  
pp. 1776-1786
Author(s):  
S. Mkhonto ◽  
H. Ewerts ◽  
A. Swanepoel ◽  
G. C. Snow

Abstract The treatment works under investigation uses a recovered wash water plant (RWWP) to remove impurities prior to recycling filter backwash water. Filter backwash water (raw water) is characterized by high quantities of cyanobacteria cells and associated organic compounds; a potential threat when recovered water is recycled. The aim of this study is to identify the cyanobacteria cells and associated organic compounds in the filter backwash water and to subsequently evaluate the effectiveness of the RWWP in removing these organic impurities during the following periods; autumn-winter and spring-summer. Results showed that at least six major phytoplankton groups were present in the filter backwash water with turbidity levels (59 and 46 NTU; autumn-winter and spring-summer, respectively) being much higher than the drinking water productions standard of ≤5 NTU. Cyanobacteria were a dominant group (mean of 80% and above) in the total phytoplankton composition of the raw water and consisted of three genera (Anabaena sp., Microcystis sp. and Oscillatoria sp.), which were effectively removed by the RWWP (up to 99%). However, associated organic compounds such as geosmin, total organic carbon (TOC), dissolved organic carbon (DOC) and microcystin were not effectively removed during the different seasonal periods but were of such low concentrations that they posed no major risk to the drinking water quality, meeting the RWWP water quality standard.

2019 ◽  
Vol 118 ◽  
pp. 03023
Author(s):  
Shuo Zhang ◽  
Ruhua Wang

According to contaminated raw water and drinking water purification processes, volatile/semi-volatile organic compounds in water are determined by GC-MS. The changes of the organic along the process and water quality from unsafe to safe process were revealed. The results show that there are odorous substances such as heptanal in raw water, which are not detected after the filtration. The composition of volatile organic compounds changes a lot after the ozone activated carbon process, thus anthropogenic pollutants are no longer detected such as 5-ethyl-5-(3-hydroxy isopentyl)-barbituric acid. However, biological metabolites that are not present in raw water such as cedrenol appear. Except disinfection by-products after disinfection, there are a variety of halogenated compounds as 1-1-dichlorocyclobutane and 1-chloro-3, 3-dimethyl-butane. Some hydrocarbons and alcohols in the finished water have little impact on drinking water safety.


2016 ◽  
Vol 17 (2) ◽  
pp. 597-605
Author(s):  
Zhiquan Liu ◽  
Yongpeng Xu ◽  
Xuewei Yang ◽  
Rui Huang ◽  
Qihao Zhou ◽  
...  

The overall purpose was to assess the feasibilities of recycling filter backwash water (FBWW) and combined filter backwash water (CFBWW) in a drinking water treatment plant in south China. The variations of regular water-quality indexes, metal indexes (Al, Mn and Cd), polyacrylamide and disinfection by-product indexes (trihalomethanes and their formation potentials) along with the treatment and the recycling processes were monitored. Results showed the recycling procedure caused increases of turbidity, total solids, ammonia nitrogen (NH3-N), permanganate index (CODMn), and dissolved organic carbon, Al, Mn and Cd concentrations in a mixture of raw water and FBWW or CFBWW compared to those in raw water. However, the recycling procedure had negligible impacts on the qualities of settled water and filtered water because most of the contaminants could be effectively removed by the conventional water treatment process. Although recycling did cause slight increases of NH3-N and CODMn levels in settled water and filtered water, the quality of finished water always conformed to Chinese standards for drinking water quality according to the surveyed indexes in the present study. Thus, it is appropriate to recycle waste streams in water-stressed areas if the source water is well managed and the water treatment processes are carefully conducted.


2021 ◽  
Author(s):  
Katie Wampler ◽  
Kevin D. Bladon ◽  
Monireh Faramarzi

<p>Forested watersheds are critical sources of the majority of the world’s drinking water. Almost one-third of the world’s largest cities and two-thirds of cities in the United States (US) rely on forested watersheds for their water supply. These forested regions are vulnerable to the increasing incidence of large and severe wildfires due to increases in regional temperatures and greater accumulation of fuels. When wildfires occur, increases in suspended sediment and organic carbon can negatively affect aquatic ecosystem health and create many costly challenges to the drinking water treatment process. These effects are often largest in the first year following a wildfire. While past research has shown the likelihood of source water impacts from wildfire, the magnitude of effects remains uncertain in most regions. In our study, we will quantify the projected short-term effects of three large (>70,000 ha) wildfires on key water quality parameters (sediment and organic carbon) in two important forested source watersheds in the Cascade Range of Oregon, US. We calibrated and validated a modified Soil and Water Assessment Tool (SWAT) to simulate streamflow, sediment loads and transport, as well as in-stream organic carbon processes for a historical period prior to wildfire. The calibrated model parameters were then modified based on literature values and burn severity maps to represent post-fire conditions of the three large wildfires. The parameter adjustments for simulating wildfire will be validated with post-fire water quality field samples from the wildfires. We will present estimations of future water quality impacts in the burned watersheds under different precipitation conditions at a daily scale for the first year following the wildfires, which will provide testable hypotheses. Additionally, we will determine catchment characteristics most critical in determining the post-fire water quality response. This work will help predict the magnitude of effects from these historic wildfires, which can inform forest and drinking water management decision making.</p>


2007 ◽  
Vol 55 (5) ◽  
pp. 161-168 ◽  
Author(s):  
T.H. Heim ◽  
A.M. Dietrich

Pipe relining via in situ epoxy lining is used to remediate corroded plumbing or distribution systems. This investigation examined the effects on odour, TOC, THM formation and disinfectant demand in water exposed to epoxy-lined copper pipes used for home plumbing. The study was conducted in accordance with the Utility Quick Test, a migration/leaching method for utilities to conduct sensory analysis of materials in contact with drinking water. The test was performed using water with no disinfectant and levels of chlorine and monochloramines representative of those found in the distribution system. Panelists repeatedly and consistently described a “plastic/adhesive/putty” odour in the water from the pipes. The odour intensity remained relatively constant for each of two subsequent flushes. Water samples stored in the epoxy-lined pipes showed a significant increase in the leaching of organic compounds (as TOC), and this TOC was demonstrated to react with free chlorine to form trichloromethane. Water stored in the pipes also showed a marked increase in disinfectant demand relative to the water stored in glass control flasks. A study conducted at a full scale installation at an apartment demonstrated that after installation and regular use, the epoxy lining did not yield detectable differences in water quality.


2001 ◽  
Vol 1 (4) ◽  
pp. 237-245 ◽  
Author(s):  
V. Gauthier ◽  
B. Barbeau ◽  
R. Millette ◽  
J.-C. Block ◽  
M. Prévost

The concentrations of suspended particles were measured in the drinking water of two distribution systems, and the nature of these particles documented. The concentrations of particulate matter were invariably found to be small (maximum 350 μg/L). They are globally in the very low range in comparison with dissolved matter concentrations, which are measured in several hundreds of mg/L. Except during special water quality events, such as turnover of the raw water resource, results show that organic matter represents the most important fraction of suspended solids (from 40 to 76%) in treated and distributed water. Examination of the nature of the particles made it possible to develop several hypotheses about the type of particles penetrating Montreal's distribution system during the turnover period (algae skeleton, clays). These particles were found to have been transported throughout the distribution systems quite easily, and this could result in the accumulation of deposits if their surface charge were ever even slightly destabilised, or if the particles were to penetrate the laminar flow areas that are fairly typical of remote locations in distribution systems.


2013 ◽  
Vol 6 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
E. R. Cornelissen ◽  
L. C. Rietveld

Abstract. To guarantee a good water quality at the customers tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research was to improve the biological stability of the produced water by incorporating anion exchange (IEX) for NOM removal. Different placement positions of IEX in the treatment lane (IEX positioned before coagulation, before ozonation or after slow sand filtration) and two IEX configurations (MIEX® and fluidized IEX (FIX)) were compared on water quality as well as costs. For this purpose the pre-treatment plant at Loenderveen and production plant Weesperkarspel of Waternet were used as a case study. Both, MIEX® and FIX were able to remove NOM (mainly the HS fraction) to a high extent. NOM removal can be done efficiently before ozonation and after slow sand filtration. The biological stability, in terms of assimilable organic carbon, biofilm formation rate and dissolved organic carbon, was improved by incorporating IEX for NOM removal. The operational costs were assumed to be directly dependent of the NOM removal rate and determined the difference between the IEX positions. The total costs for IEX for the three positions were approximately equal (0.0631 € m−3), however the savings on following treatment processes caused a cost reduction for the IEX positions before coagulation and before ozonation compared to IEX positioned after slow sand filtration. IEX positioned before ozonation was most cost effective and improved the biological stability of the treated water.


2021 ◽  
Vol 277 ◽  
pp. 04003
Author(s):  
Ayu Widya Utami ◽  
Dwi Nowo Martono ◽  
Haruki Agustina

West Tarum Canal (WTC) is a canal that drains raw water from the Jatiluhur Dam. Nearly 81% of the raw water for drinking water used by Jakarta’s people comes from this canal. However, various land uses such as agriculture, industry, settlements, and infrastructure development impact WTC’s water quality. This research aims to assess WTC’s water quality in 2016-2020 based on water quality standards set by the Government and using the STORET method. The results of this research indicate that the concentrations of TDS (142-351 mg/L), Fe (0.1-0.15 mg/L), Mn (0.03-0.1 mg/L) are meet the standards, while DO (3.6-4.9 mg/L), BOD (4-10 mg/L), COD (13-30 mg/L) are not meet the standards. Almost all monitoring points have pH values between 5.75-7.68 that are meet the standards. The STORET score of WTC is from -26 to -38 with an average of -30, which indicates that WTC’s water quality is moderately polluted. Water contamination in WTC will burden the drinking water processing and ultimately affect the community’s ability to pay for drinking water. This research also shows the need for integrated management of WTC from upstream to downstream and the need to increase collaboration between stakeholders in carrying out this management.


2020 ◽  
Vol 20 (6) ◽  
pp. 2106-2118
Author(s):  
Kassim Chabi ◽  
Jie Zeng ◽  
Lizheng Guo ◽  
Xi Li ◽  
Chengsong Ye ◽  
...  

Abstract People in remote areas are still drinking surface water that may contain certain pollutants including harmful microorganisms and chemical compounds directly without any pretreatment. In this study, we have designed and operated a pilot-scale drinking water treatment unit as part of our aim to find an economic and easily operable technology for providing drinking water to people in those areas. Our small-scale treatment unit contains filtration and disinfection (UV–C irradiation) stages to remove pollutants from source water. The water quality index was determined based on various parameters such as pH, temperature, dissolved oxygen, nitrate, nitrite, ammonium, phosphorus, dissolved organic carbon and bacteria. Water and media samples after DNA extraction were sequenced using Illumina MiSeq throughput sequencing for the determination of bacterial community composition. After the raw water treatment, the reduction of bacteria concentration ranged from 1 to 2 log10. The average removal of the turbidity, ammonium, nitrite, phosphorus and dissolved organic carbon reached up to 95.33%, 85.71%, 100%, 28.57%, and 45%, respectively. In conclusion, multiple biological stages in our designed unit showed an improvement of the drinking water quality. The designed drinking treatment unit produces potable water meeting standards at a lower cost of operation and it can be used in remote areas.


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