A water quality analysis of rainwater collected from different roof catchments in rural, urban and industrial areas was conducted to determine its suitability for domestic purposes. Examination of the collected rainwater samples indicated that the bacterial quality was poor, and the physical and chemical qualities varied between each area and between each site. Rainwater from industrial area roof catchments had lead concentrations averaging two-fold higher than the WHO drinking water guidelines and also had high levels of turbidity, suspended solids and zinc. Water collected from rural area roof catchments had a higher concentration of nitrates and a slightly higher pH. Although lead was detected in urban area roof catchments, concentrations were not as high as the concentrations in the industrial area. The different roof types had an influence on the rainwater quality with zinc concentrations higher in galvanised iron roof catchments, while pH, conductivity and turbidity levels were higher in concrete tile roof catchments. The pollution of rainwater collected from roof catchments was mainly due to the diffused pollution from atmospheric deposition, and the number of dry days preceding a rainfall event affected the collected rainwater quality.
Pilot scale investigations were carried out to examine the pollutant removal efficiency of a constructed wetland receiving secondary treated sewage effluent. Four constructed wetland cells were established, three of them planted with either Schoenoplectus validus, Juncus ingens or both species of macrophytes, and the fourth serving as an unvegetated control cell. Although there was a significant improvement in the effluent quality during the initial ten month period of monitoring, results to date have not indicated any overall trend for pollutant removal by a particular plant species. Biochemical oxygen demand and chemical oxygen demand removals averaged between 71-75% while suspended solids removals were around 85% in the macrophyte cells. Ammonia reductions were in the range 17-24% but better nitrate reductions between 65-80% were obtained. Phosphorus removal has been low (13%) in all four of the wetland cells and bore hole samples have shown no groundwater contamination with nitrogen or phosphorus from the wetland system to date.
Domestic food waste disposers (FWDs) have recently come to prominence as a possible alternative for disposal of organic waste, to reduce the quantities of this type of waste sent to landfill. There has been little research undertaken on the potential effects of food waste on the wastewater system, and it is believed no previous practical studies have been undertaken in the United Kingdom. In this study, food waste was ground in an FWD and analysed for chemical oxygen demand (COD), biological oxygen demand (BOD), ammonia, total nitrogen, total phosphorus, total suspended solids and rapidly settleable solids to determine their effects on the wastewater system. The largest impacts were on COD, BOD and suspended solids, compared with the amounts of these determinands that currently arrive at sewage treatment works (STW). Experiments using settled samples showed that a relatively high proportion of nitrogen, phosphorus, COD and BOD would pass through to secondary treatment at the STW.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.