Developing an Integrated "Regression-QMRA method" to Predict Public Health Risks of Low Impact Developments (LIDs) for Improved Planning.

Worldwide Low Impact Developments (LIDs) are used for sustainable stormwater management; however, both the stormwater and LIDs carry microbial pathogens. The widespread development of LIDs is likely to increase human exposure to pathogens and risk of infection, leading to unexpected disease outbreaks in urban communities. The risk of infection from exposure to LIDs has been assessed via Quantitative Microbial Risk Assessment (QMRA) during the operation of these infrastructures; no effort is made to evaluate these risks during the planning phase of LID treatment train in urban communities. We developed a new integrated "Regression-QMRA method" by examining the relationship between pathogens' concentration and environmental variables. Applying of this methodology to a planned LID train shows that the predicted disease burden of diarrhea from Campylobacter is highest (i.e. 16.902 DALYs/1000 persons/yr) during landscape irrigation and playing on the LID train, followed by Giardia, Cryptosporidium, and Norovirus. These results illustrate that the risk of microbial infection can be predicted during the planning phase of LID treatment train. These predictions are of great value to municipalities and decision-makers to make informed decisions and ensure risk-based planning of stormwater systems before their development.

Investigating the public health risks of low impact developments at residential, neighbourhood, and municipal levels.

Low Impact Developments (LIDs) employ a series of vegetative techniques to retain rainfall close to the site of origin. Although LIDs offer sustainable runoff management, these infrastructures can be considered a risk to public health due to the presence of pathogens in the runoff and human exposure to contaminated water held in and transported by LIDs. The objective of this study is to examine the disease burden of Gastrointestinal illness (GI) from exposure to LIDs at the residential, neighbourhood, and municipal levels. The authors conducted a meta-analysis of literature on three water features: (1) harvested rainwater obtained from LIDs, (2) surface water, and (3) floodwater. A set of 32 studies were systematically selected to collect values of risks of infection and expressed as the disease burden, i.e. disability adjusted life years (DALYs). The results showed that the percentage of GI illness exceeding the health guidelines were high for harvested rainwater, i.e. 22% of annual disease burden exceeded the WHO guidelines (0.001 DALYs/1000 persons), and 2% exceeded the US EPA guidelines (5.75 DALYs/1000 bathers). Among the six exposures for harvested rainwater, exposure to spray irrigation, exceeded US EPA guidelines whereas; five exposures, i.e. flushing, hosing, daily shower, spray irrigation, and children playing, surpassed the WHO guidelines. Considering LID treatment, the values of annual disease burden from all the selected barriers were below US EPA guidelines however, these values exceeded the WHO guidelines for three barriers i.e. water plaza, grass swale, and open storage ponds. These findings provide a broader perspective of the disease burden associated with LIDs and emphasise to consider the type of exposures and required treatment barriers for developing LID infrastructures in urban areas.

State of provincial regulations and guidelines to promote low impact development (LID) alternatives across Canada: Content analysis and comparative assessment.

The use of Low Impact Development (LID) alternatives requires the establishment of appropriate regulations and guidelines on acceptable practices and developing consensus among stakeholders, thus assuring the rights of all water-users and for conflict resolution. This content analysis aims to examine whether stormwater regulations and guidelines have addressed the use of LID alternatives in urban settings and compares the current state of regulations in the context of Canadian provinces and territories., A list of eight core criteria relevant to the implementation of LID has been identified and an ordinal scale ranging from 1 to 6 is proposed to track the progress towards LID-friendly regulations in each province. Furthermore, based on comparative assessment, Canadian provinces are categorized into three groups: 'highly, moderately, and slightly LID-friendly' to project a broad view of the current state of regulations required to promote LID alternatives. . Results show that LID has become the mainstream technology for stormwater management in Alberta, British Columbia, Ontario, and Quebec, which are categorized as 'highly LID-friendly' provinces. The provinces where LID alternatives have gained considerable acceptance are categorized as 'moderately LID-friendly', which include Manitoba, Newfoundland and Labrador, Nova Scotia, Prince Edward Island, and Saskatchewan. Lastly, the province of New Brunswick is categorized as 'slightly LID-friendly', because of very limited use of LID alternatives in the stormwater management regulations. These findings of this content analysis can be of significant value to strengthen provincial/territorial regulations and extend the benefits of LID in stormwater quality management and sustainable water management.

Chlorination and water quality monitoring within a public drinking water supply in Rawalpindi Cantt (Westridge and Tench) area, Pakistan.

Concern over the presence of fecal coliform in public drinking water supplies has been expressed in recent years in Pakistan since it has been regarded as pathogenic organism of prime importance in gastroenteritis. Two major drinking water distribution systems in the Cantt area of Rawalpindi district covering the Westridge and Tench areas was monitored over a 2-month period to determine the prevalence of fecal coliform and chlorine residual. The collected samples were examined for total chlorine, free chlorine residual, chloramines, total coliforms, fecal coliforms, and turbidity. The drinking water quality monitoring in the distribution network was performed by collecting samples from water source, overhead reservoir, and residential taps. In the Westridge area, total chlorine varied from the lowest value of 0.27 mg/L at Station # W-5 to the highest value of 0.42 mg/L at Station # W-2, total coliforms varied from 1.1 to 3.6 most probable number (MPN)/100 mL with presence of Escherichia coli in all samples, total dissolved solids (TDS) ranged from 199.5 to 205 mg/L, conductivity fluctuated between 399 and 411 microS/cm, and turbidity varied from 0.43 to 0.73 NTU. In the Tench area, the value of total chlorine ranged from 0.14 mg/L at Station # T-7 to 0.55 mg/L at Station # T-1. Total coliform varied from 3.6 to 5.1 MPN/100 mL and fecal coliform were detected at all the stations except at Station # T-1. TDS ranged from 201.4 to 257 mg/L, conductivity varied from 343 to 513 microS/cm, and turbidity ranged between 0.66 and 1.55 NTU. It is recommended to the respective agencies to ensure that the chlorine residual is available at consumer end.

Monitoring of Coliforms and chlorine residual in water distribution network of Rawalpindi, Pakistan.

The present study was undertaken to examine the drinking water quality of Rawal Treatment Plant, Rawalpindi and its distribution network by collecting samples from eight different locations. The aim was to determine potential relationship between the presence of microorganisms and chlorine residual in the distribution network. Quantification of chlorine residual, turbidity, standard plate count (SPC), fecal and total coliforms by Most Probable Number (MPN) was performed. Three different forms of chlorine were measured at each sampling station such as free chlorine, residual chlorine, chloramines and total chlorine residual. A critical evaluation of data presented indicated that pH generally ranged from 7.02-7.30; turbidity varied from 0.34-2.79 NTU; conductivity fluctuated from 359-374 microS/cm; and TDS values were found to be ranging between 180-187 mg/l. Station # 7 was found to be most contaminated. The value of total chlorine was found to be 0.86 to1.7 mg/l at Station # 3 and 6, respectively. Highest standard plate count was 62 CFU/ml at Station # 7. Total coliforms were less than 1.1 MPN/100 ml at almost most of the stations except at Station # 3 where it was found to be greater than 23.0 MPN /100 ml. Overall aim of this study is to create awareness about contamination of drinking water in the water distribution networks and to make recommendations to provincial agencies such as EPA, CDA and WASA that regular monitoring should be carried out to ensure that the chlorine residual is available at consumer end.

Simultaneous nitrification-denitrification in slow sand filters.

While the ability of slow sand filters to remove total suspended solids (SS), turbidity, and organics from wastewaters is well known, this study has demonstrated that they can also achieve simultaneous nitrification-denitrification, producing effluent total Kjedahl nitrogen (TKN) and total nitrogen (TN) concentrations as low as 0.6 and 1.5mg/l, respectively, utilizing particulate and slowly biodegradable COD in the process. The impact of filtration rates in the range of 0.15-0.38m/h, filter depth of 0.5-1.5m, and sand size 0.3-0.5mm on nitrogen removal processes at temperatures of 10-39 degrees C was assessed. Nitrification efficiency, denitrification efficiency, and total nitrogen removal efficiency correlated well with filtration rate and sand size only, with all three parameters inversely proportional to the square root of the aforementioned two process variables. Nitrification exhibited the most sensitivity to filtration rate and sand size. The filters produced effluent with turbidities of 0.1-0.5 NTU, SS concentrations of 3-6mg/l in the fine sand and 6-9mg/l in the coarse sand. Effluent BOD(5) and COD concentrations were mostly in the 0.8-2.6 and 15-34mg/l range, respectively.