This is another report which Dr. Arno shared last week about irrigation with not treated ,raw and hazard sewage in crops cultivation
www.huffingtonpost.com/entry/climate-was...3d27e4b005b0fdc96273
.I attached my article which published in September 2011 about irrigation with non treated sewage in Local Daily newspaper Khorasan I explain historical mismanagement in water safety and sanitation and I offered a proposal solutions , It was in Farsi and that time was informative article which made trigger some activity for safe management for hazard waste water.


Mohammad

Dear Dr. Arno,

This link (www.dw.com/en/wastewater-crop-irrigation...on-people/a-39538101) also carries the same story. It also gives a link to a study Environmental impacts of wastewater
from urban slums: case study - Old Fadama, Accra (attached). The abstract reads:

The burgeoning of slums in the developing world poses an urgent environmental threat due to insanitary conditions and rampant disposal of wastewater. To assess the potential environmental impacts, domestic wastewater from Ghana's biggest urban slum - Old Fadama was characterised throughout the dry and wet seasons. The study drew on a comprehensive assessment of the general sanitary conditions in the community to determine the sources of pollution and water quality monitoring. BOD5 levels of wastewater from the study area were 545.63±99.88mg/L and 645.94±331.43mg/L in the dry and wet seasons respectively whereas COD levels were 1100.45±167.16mg/L and 1415.12±722.83mg/L in the dry and wet seasons respectively. E-coli levels were 4±1x106CFU/100mL and 4200±2400 x106CFU/100mL in the dry and wet seasons respectively whereas total coliform levels also showed the same trend with 9±2106CFU/100mL and 16800±5100106CFU/100mL in the dry and wet seasons respectively. The study identifies that wastewater from this community has potential deleterious environmental implications due to high levels of nutrients, oxygen-demanding substances and faecal coliforms. Pollutants were identified to be emanating predominantly from open defecation and indiscriminate waste disposal. Efforts should thus be directed
towards improving sanitary conditions viz. access to toilet facilities, waste disposal mechanisms and best
management practices for wastewater.

Please note that this is Ghana's biggest urban slum, and the BOD value is 545 mg/L. The high BOD value is indicative of less availability of water (and hence the concentrated wastewater). This is also the case here in Karachi's peri-urban areas, where localities gets little water, and produce concentrated wastewater.

The paper rightly recommends improvement in sanitary conditions, access to toilet facilities, waste disposal facilities, and best practices for wastewater management.

Regards,

F H Mughal

For Elisabeth: The number 3 in above figures is at a lower level. Why it is so?

New Data on Untreated Wastewater Reuse in Agriculture – 50% higher than previous estimates

In a new paper by Thebo, Drechsel, Lambin and Nelson (Environ. Res. Lett. 12 (2017) 074008) (see attached) and covered by BBC July 5, 2017 www.bbc.com/news/science-environment-40494254 it is concluded that nearly 30 million hectares are now receiving untreated wastewater within 40km of an urban centre. Some 885 million people, including farmers, vendors and consumers are said to be exposed to serious health risks. China, India, Pakistan, Mexico and Iran account for most of the irrigated land and there are several smaller developing countries that contribute to the total.

This again reinforces the fact that most urbanites do not understand the risks surrounding wastewater reuse. Reuse of wastewater is an important and environment-friendly development on the increase but for this to work, the cities of the world need to treat their wastewater to reduce pathogens. Clandestine reuse of untreated wastewater in farming therefore requires much more attention. There is an acute need to treat the produce from these farms carefully to reduce exposure to fecal bacteria and make people aware that this is a necessity to reduce disease.