The objective of this paper is to present an overview of state regulations and guidelines for wastewater reuse for irrigation. Land application of wastewater in the U.S. began in the 19th century when it was considered the safest and best method for wastewater disposal. According to the Environmental Protection Agency (EPA), 27 states have regulations for wastewater reuse and 11 states have guidelines for reuse. Some states have no regulations or guidelines for wastewater reuse. For urban wastewater reuse for irrigation where public access is not restricted and for irrigation of food crops, many of the states require additional levels of treatment beyond secondary treatment, which may include oxidation, coagulation, and filtration and high levels of disinfection. California, Arizona, Texas, and Florida were the earliest states to establish water reuse programs and account for the majority of wastewater reuse for irrigation in the U.S. Several of the challenges to increase wastewater reuse are water rights in the western states and a lack of funding for new projects.

Municipal solid waste management in India is often one of the largest components of a municipality's budget. In India municipalities spend in the range of 20-50% of their budgets on the handling of municipal waste. Waste collection in cities is inefficient in more ways than one. The lack of garbage bins on city streets combined with carefree attitudes toward littering and weak enforcement of laws against littering result in unsightly streets. Landfills are located on the periphery of cities where many low-income communities reside. Subsequently some populations also relocate to areas surrounding landfills because picking apart recyclables from landfill garbage is a source of revenue for these urban poor. These populations are exposed to the first-hand effects of dangerous pollutants in the air, rivers, and streams that surround them. This paper will explore several technologies available for the reuse of waste and attempt to put forward policy recommendations for alleviation of the problems of waste in cities. Solid waste management in Prune and Bangalore are discussed as case studies. Solutions to municipal solid waste management in India include technical, economic, and social challenges.

Agriculture drainage increased from the early 1900s to the early 1980s. During the 1970s and 1980s increasing environmental concerns increasingly viewed agricultural drainage as being against the public’s best interests. The Clean Water Act amendments in 1977 and the Food Security Act of 1985 all had an effect on agricultural drainage. Water quality effects of agricultural drainage projects started to be reported in the literature in the 1970s and 1980s. There were a number of projects conducted in the Northeast. To address water quality concerns, some controlled drainage systems were installed on the Delmarva Peninsula in the 1990s. Research has shown subsurface drainage can transport large amounts of nitrogen to surface waters. New York has a large dairy population, so manure is the largest input of nitrogen to surface problems in a number of watersheds. Also of concern is the rapid transport of nitrates and bacteria by preferential flow to subsurface drains when liquid manure is spread on fields. On the Delmarva Peninsula poultry manure has been a great concern for many years of in the Chesapeake Bay and Inland Bays watersheds. With the release of the TMDL by EPA in 2010 for the Chesapeake Bay it has become more of a concern.

Wastewater reuse was stared in Delaware in the 1960s when the food processing companies Clifton Canning, Wheatley Foods, Cannon Foods, and American Original using spray irrigation. They all applied the wastewater to reed canary grass or other types of grasses. Cannon Foods pastured beef cattle on their site. In 1970s Townsend started using spray irrigation on corn for their wastewater from their poultry processing plant. The Townsend Company was sold in 2002 to Mountaire Farms. Today they apply wastewater to corn and soybeans on approximately 1,000 ac. Spray irrigation was proposed for the resort towns of Rehoboth Beach and Lewis in the 1970s and for the town of Bridgeville in the 1980s. Both proposed projects were abandoned because of strong public opposition. In the 1990s three systems in the Inland Bays watershed and Water Farm #1 were constructed and began operation. In 2002 the town of Middletown started using spray irrigation. Today there is a great interest in rapid infiltration systems (RIBs) in Delaware. The first wastewater reuse project in Maryland began the 1940s when millions of gallons treated water from Baltimore City's Back River wastewater treatment plant were diverted daily to the Bethlehem Steel plant to be reused for industrial purposes before being discharged into the Patapsco River. The three dominant types of reuse in Maryland today are for irrigation (55%), cooling water (34%), and groundwater recharge (13%).

Biosolids management can be a source of greenhouse gas emissions (GHG). Biosolids treatment and end use technologies can constitute up to 40 % of total emissions associated with wastewater treatment. Combustion and landfilling of biosolids are the main sources of emissions. The greenhouse gases that have the potential to be emitted from composting operations are CH₄ and N₂O. Composting is an aerobic operation, but since the environment is not uniform in a compost pile, anaerobic pockets may exist. If the C:N ratio is < 30 and the moisture content is < 55 % GHG emissions will not occur during the composting process itself. Land application of biosolids will add organic matter to the soil which will help sequester C. Biosolids also reduces the need for commercial fertilizers which also produces additional credits for GHG emissions. There is great uncertainity in N₂O emissions from land application.

Municipal wastewater treatment processes and operations at the wastewater treatment plants (WWTPs) include various solid-liquid separations, removal of organic and inorganic contaminants, and the environmentally safe disposal of treated wastewater final effluents and sludges (or biosolids, as applicable). Municipal wastewater treatment operations in the US have various applicable air, water, and waste control requirements under the local, state, and federal regulations. Current, wastewater treatment and water management practices need to be evaluated for effective ways to control energy requirements and promote energy recovery at the WWTPs and, the effluent reuse possibility. In addition to the environmental compliance requirements of wastewater treatment and management, the energy usage requirements at the WWTPs are critical in that the utility rates at a kilo-watt-hour (kWh) are significant since the wastewater treatment needs to be conducted as the sewage, infiltration/inflows (I/I), and wet-weather flows are received at the WWTPs. Authors are associated with several, performance based, wastewater treatment projects for guaranteed energy savings without compromising the environmental compliance requirements of the WWTP facilities. This paper included a review of typical municipal wastewater treatment train, environmental compliance requirements, energy usage and control, and energy recovery opportunities at the municipal WWTPs, including the buildings.